What is the “highest” HP someone has put into a Kitfox?

[Rik]

So I’m curious as to how much hp is to much, meaning the plane will hit a wall and not go any faster due to the drag, and any more hp will just get the plane up and into the air but have little effect on the top end speed.

I know the planes not going to ever be a “fast” plane but reading most owners performance evaluation, 90 mph is to slow to get to an area to enjoy the planes other attributes.

I have a vision, but of course I know it’s stupid but never hurts to ponder.

TIA

[airlina]

I would say that generally around 120 MPH TAS is the sweet spot for my 125 HP Series 5 (Continental IO-240) . I can go a tad faster with higher power settings but everything is smoother at the 120 MPH setting which is about 65 % power. Others will chime in here ,but I suspect you will find 120 MPH to be the majic number at least on the well powered later model Kitfoxes. Bruce N199CL

[Dave S]

Although I have "only" 100 hp up front, I have come to the conclusion that the current wing design works great up to about 120 MPH.


I recall doing VNE testing to 140 and it took some coordination between power (to keep from redlining the engine) and pitching down to get to 140 - felt like the aircraft was fighting a lot of rapidly increasing drag getting to the target speed for the purpose.


An airplane is designed around the wing and I doubt that superpowering a kitfox would result in balanced performance. It's a kitfox, not the space shuttle and I love it for what it was designed to do:). I guess I never got a kitfox to find out how fast I could get out of the sky and back on the ground:rolleyes:


IMHO - 120 MPH is a reasonable max cruise for the design. I normally run 110-115 MPH cruise with 100 HP.

[Rik]

Thanks, I’m pleased that the planes can reach 120 as nearly every review claims 90-100 max and that’s mph not knots they say.

Hard to do any STOL when you have to spend all day getting to an area then all day getting back.

Now with sufficient power, can an S7 be competitive at the stol drags???

[Slyfox]

I am thinking at this point of a few people that have the high HP kitfox's, called I believe the Cub Killer. I think the main purpose in their mind is to get off the ground faster and climb somewhat straight up. what their top speed really doesn't matter to them.

I personally have the 4 with the uls 100hp engine. along with the adjustable prop in flight and the fact that it is light, 650 dry. I can get some great take off's. Ya nothing like that 140+ wonder out there I'm sure, but it is fun and the aircraft handles very light with the power to weight ratio. Oh and I can fly 102kts all day long. My smooth ride is at 84kts which I do a lot for fun flying. 102kts I do to get to my play area faster. speed is important only because I have a busy schedule in my life and I only have so much time for play. can I put more horsepower on my plane, sure, but more HP cost money. sure I can do it, but I love the way it is now and I'm just going to leave it. I'm more interested in TBO at this point and I know the stock 912uls has a good one. I vote on my plane to leave it be and enjoy what I have.

[aviator79]

Now with sufficient power, can an S7 be competitive at the stol drags???

Trent answered this definitively, didn't he? In case you didn't follow the results, he and his much upgraded KF5 placed 2nd to Draco.

If you want to squeeze more speed out of a Kitfox so you can cover more ground more quickly, consider a turbo instead of just a bigger engine with higher nominal HP. Brandon had the STi doing 140 mph GS at 17999 on the way to OSH. Full disclosure: he had a tailwind, and did not have a readily available TAS figure. Still, being able to get into rarified air, and being able to select an altitude with favorable winds is a big plus.

[Rik]

At 17,999' I'm sure he has a turbo as there's not much air up there to run an engine. 140 gs is good but as you noted tailwind. At those elevations it's not uncommon to see 50 knot tailwinds.

It's hard to get one plane fulfill multiple missions I see.

Just wondering if there were any S7's with the same Lycoming that the Carbon Cubs are using that are tweaked to 200 hp

[jiott]

There is an Avid Magnum in my area that has 180 hp Lyc I believe.

[Dorsal]

Not sure where you are getting the 90-100 mph figure from, mine is a pretty standard 7 with 100 ponies and does 120 fairly comfortably.

[DesertFox4]

Lots of misconceptions circulating yet about cruise speeds and adverse yaw.
I ran into those questions at the Kitfox booth at Oshkosh yet this year.

Most attributable to the Models 1,2 & 3’s. Of course the adverse yaw issue was solved with the model 4’s and newer model’s redesigned control mixer along with larger tail control surfaces.

The speed questions likely relate back to earlier models and some early model 4’s equipped with 2 stroke engines. If you are not cruising at 105 to 110 mph or better in a model 4 with a Rotax 80 hp and up, something is amiss.

[Rik]

Thanks, I was thinking of building/acquiring a S7 STi and they don't seem that fast with the big tires and I don't know how much of this is the tires and how much of this is the wing.

Just watching YT Video's such as Trent's and others with a 100 hp (minimum) engine and they are cruising in the 90-100 range and odds are more often closer to the 90 than the 100.

I do not care about meeting the LSA requirements if this matters. I see a lot of comments on this site in reference to the LSA rules but I don't have a sport pilots license so I don't really care. I'm out for fun not a loop hole to allow it.

I'm still in the planning stage and I don't even know if a KF is the best option for me. I want a STOL plane and I have a distaste for a tandem setup so side by side options tend to be between the KF and the JUST.

[Slyfox]

you got to understand, those guys don't give a care about what their top speed is. they want off fast. climb out is their game. basically. I do believe the sti wing is a low stall not so fast wing. that's what I heard anyway. you need to figure out your mission. the standard super sport in my opinion would cover 90% of what a person in reality would want and need. I know trent is getting everybody a hard on for the STOL flying that he and his friends are doing. You just need to figure out if it's what you want. like I said the standard super sport is a great airplane on it's own. best thing it will go 120 with the 912uls. still land short and have a ton of fun.

[Rik]

This is kinda why I am asking. The 120 to get there and then the fun once you can get to a place to have fun. Not exactly a plane to travel 350 miles with but 100'sh seems ok and then the HP concern was that I could use that to get the plane to climb to compensate for the faster wing, ad VG's and such and be a decent compromise.

I have a crazy engine plan but who knows

[Slyfox]

I think there is at least some things to think about for fun. Do you want to go out and lets say fly 20 off and zip around trees and play in the canyons. Do you want to go out and have fun landing and taking off in areas that have nothing but your guts to regulate where you land. Do you want to go out and land at grass fields in the back country and be satisfied with those type of landing areas with a seldom spot like a river bed. The middle one is extreeeem flying and can bite you real quick, the other two not so much. The first one you will do believe it or not just because you will be in the back country and it will happen. landing in the grass fields is really fun and you can do that with a standard kitfox along with the first example. now the middle one, not so much, like I said it can bite you. Now you need the freedom Fox type of machine. with some balls to go with it.

[Rik]

The canyon flying seems like fun but I think more people get killed doing that as there's typically little speed involved, most of these planes have little hp to spare, and if the terrain closes in on you your done. This happend to ICON at Lake Berryessa. Couldn't get out of the way of the terrain.

There are no rivers near me so it'd probably be more of landing in the desert areas after a sweep run to be honest. Stopping in 10-100' is bragging but not important, to me. Climbing like a rocket would be more fun too so that's why I asked about the hp.

I'm new to these forums but it's easy to get confused as KF makes/made several versions and the forums are all inclusive of a K1 to k7 and people are coming from their experiences with different planes so it takes a while to get a grip on what a K3 is vs a k5 and so forth. I say S7 as it's what's made today.

[896tr]

So Rik, you could put a stock Subaru WRX-STI motor in a plane and have 300 horse power with 6 cylinders, great for a dune buggy (I had one) but more horse power will always mean more weight. Not great for a stol plane. Don't forget what vne means, velocity never exceed speed. Isn't the series 7 vne around 140 or 150 mph? you can call John or Debra at Kitfox and ask them for their recommendations based on your skill level and objectives they will always give you an honest answer, why would they want jeopardize their reputation and company with false or bad information. Better yet, make an appointment with Stick & Rudder for some instruction then make a decision on what you need. You could be in for a surprise when you actually have real time in a Kitfox. I have never read about or heard anyone complain that their Kitfox is a disappointment.

[Rik]

I'm sure they are great planes. I'm not going to be considering a car engine in a plane like this. Very counter productive, yet I see they are putting a Yamaha Snowmobile engine in a Highlander, I have more exotic plans

[DesertFox4]

The STi wing is a higher lift wing so that makes it slower than the standard wing by about 20 mph or so using the same engine in each for comparison. It does come with a lower stall speed.
The standard wing is what Stick & Rudder uses on their training Kitfox’ and Stick & Rudder is the gold standard for back country flight instruction in some of the most challenging fields in Idaho. One has the 914 turbo and the other is a 912 fuel injected 100 hp.

The vne speed is 140.

[TY2068]

I'm going to blow your minds. I fly ALL the time (last 20 years) with just 19hp and it's an absolute blast. I fly more than anything in my area. I say just get out there and get GOOD at flying with whatever you have.... 80,100,115, 500hp who cares...HP is not going to make you a better pilot.

https://m.youtube.com/watch?v=JvkTn8YGDaU

[Rik]

The STi wing is a higher lift wing so that makes it slower than the standard wing by about 20 mph or so using the same engine in each for comparison. It does come with a lower stall speed.
The standard wing is what Stick & Rudder uses on their training Kitfox’ and Stick & Rudder is the gold standard for back country flight instruction in some of the most challenging fields in Idaho. One has the 914 turbo and the other is a 912 fuel injected 100 hp.

The vne speed is 140.

Yea, I was reading the VNE is 140, but VA is not listed which is more important.

[Slyfox]

ya, the 140 really doesn't mean anything other than don't point the nose down and let her go. I don't think you are going to get that really, level flight. yes I have had to watch the vne in my 4. Like I said the ss model is a great airplane if your looking for a new one or newer model. The sti sounds good, but I think it would be limiting too much. when it comes to performance, don't think Cessna in the back country, these little planes really do perform. I have no problem with mine even if I ended up in a closed canyon. I know my airplane can do a turn around in the closest area. not going to say anything more, of course there is always the hammer head wing over, which is real fun also. these things are some of the things you learn for back country. of course, don't just go back there, get training, there is a bunch of options for that. I think for the first time flyer or low time pilot the model 4 -7 would be more than enough for a real good time and you don't have to learn all the fun stuff right away, you will learn with a life time of experiences that will go on like the energizer bunny.

[efwd]

Man, Slyfox is a wise fox for owning a Kitfox. :rolleyes: I agree with all that you have said here. I was extremely taken back at the information overload I got from Paul at S&R as he introduced me to backcountry landing.

[Rik]

ya, the 140 really doesn't mean anything other than don't point the nose down and let her go. I don't think you are going to get that really, level flight. yes I have had to watch the vne in my 4. Like I said the ss model is a great airplane if your looking for a new one or newer model. The sti sounds good, but I think it would be limiting too much. when it comes to performance, don't think Cessna in the back country, these little planes really do perform. I have no problem with mine even if I ended up in a closed canyon. I know my airplane can do a turn around in the closest area. not going to say anything more, of course there is always the hammer head wing over, which is real fun also. these things are some of the things you learn for back country. of course, don't just go back there, get training, there is a bunch of options for that. I think for the first time flyer or low time pilot the model 4 -7 would be more than enough for a real good time and you don't have to learn all the fun stuff right away, you will learn with a life time of experiences that will go on like the energizer bunny.

Is the “hammerhead wing over” a stall?

[mscotter]

No, it's a turning maneuver for reversing course in smallest possible area. If you've ever seen an acro performance you've likely seen a hammerhead demonstrated. In the hands of the right pilot, it's quite impressive.

[Rik]

That’s pushing it. These things aren’t acrobatics raterd are they?

[aviator79]

Yea, I was reading the VNE is 140, but VA is not listed which is more important.

Vno might be more applicable than Va. Va would be an extremely conservative cruise speed in most airplanes. Incidentally, does anyone know what Vno and Va are published as for the SLSAs?

(Edit: I just remembered that I programmed this into my EFIS already: Vno is 139, so basically, you're good all the way up to Vne.)

If you're concerned at all about cruise speed, you want the standard wing. I agree with Slyfox. STOL is en vogue right now, and a lot of people are going for the STi wing. But the standard wing on the Kitfox hits a pretty nice sweet spot, and still gets you into and out of just about everywhere you've seen Trent land.

I'll bite. What are your more exotic engine plans?

[aviator79]

That’s pushing it. These things aren’t acrobatics raterd are they?

Check this out. Probably won't do this with the STi wing.

https://www.youtube.com/watch?v=mFwPlP4CZ6o

[Slyfox]

Vno might be more applicable than Va. Va would be an extremely conservative cruise speed in most airplanes.
I'm pretty sure there are things that Trent and the cowboys are doing that will never be put into vids. with my little 4 I can come in and land and use 300ft. that's pretty short, not for competition standards, but who cares in my opinion. Most pilots I'm going out and say 95%, will never use what the sti has to offer. Most those pilots will be doing an airline approach and landing. I never do a landing that isn't a short, most are radical shorts. That's with my 4. I have no plans on the sti wing, don't know if it can go on my fox, I'm sure it could be done. I love my 120mph too much. I do believe my landing speed is right at 35mph in ground effect. that's good enough for me. I know I can bring my fox in and land it where I want it and do a good short, better than 95% of the pilots out there. something to think about. :)

[Slyfox]

One more thing to put into the fire. I would really like to do more with my kitfox but I feel limited. Why? there is nobody in my area that likes to fly like me. LOW AND SLOW. What you say, yup, most people want to go up to 2k above ground. no fun up there. I like to fly in the boonies and fly low and canyon run. haven't found anybody that likes that here. So you may aspire to fly like trent, but having a wing man I feel is very important. why? if there is trouble, there is a person to cover your back. I fly to small airports in the mountains, but I don't really like it by myself. wish I had a wing man.

[jiott]

Regarding Kitfox "acro" rating, yes the factory says not rated for aerobatics, but the SS7 IS rated for +4, -2 g's. So if you keep it within these limits the airplane doesn't know or care whether you are doing "acro" or not.

[kitfoxjim]

This summer I installed an O-360 J2A heli engine in my standard wing model 5. It's equipped with SDS ignition and fuel injection. I could very well be the high HP winner! It replaced my previous O-235 because I got a deal that I couldn't refuse. Depending on who you talk to this 360 is from 25 to 40 lbs. lighter than the standard aircraft 360.
I'm still in the experimental stage and I don't feel the 72" prop I am currently using gives me maximum performance. Having said that, it is easy to get up to Vne in level flight if you don't care about fuel consumption. This does present problems during the break-in phase where you want to run the engine hard!
Performance wise I see about 1700 fpm at 80mph and take off in about 350 ft.
My empty weight is 1010 lbs.

[jmodguy]

I have a KF5 with an an IO-340 and the FlyEFII system, cold air sump and a Whirlwind GA-200 STOL prop. Hope to fly in the spring... yeah right...
I'll be staying with the standard wing. I am considering fenced wingtips and a fence on the wing like the STi. I have the winter to get my composite work done.


Would like to hear more performance specs from Kitfoxjim!

[Rik]

Vno might be more applicable than Va. Va would be an extremely conservative cruise speed in most airplanes. Incidentally, does anyone know what Vno and Va are published as for the SLSAs?

(Edit: I just remembered that I programmed this into my EFIS already: Vno is 139, so basically, you're good all the way up to Vne.)

If you're concerned at all about cruise speed, you want the standard wing. I agree with Slyfox. STOL is en vogue right now, and a lot of people are going for the STi wing. But the standard wing on the Kitfox hits a pretty nice sweet spot, and still gets you into and out of just about everywhere you've seen Trent land.

I'll bite. What are your more exotic engine plans?

I have one so I was considering to do something with it, an Allison C250

[aviator79]

That would be quite a conversation starter. I'm guessing that engine burns in the neighborhood of 20 gph in cruise. You'd want to add some fuel capacity I would imagine.

[Rik]

Yea, hence the need for some speed as the fuel mileage gets better the faster one goes.

The standard wing on the K5 is kinda scary as it’s what Nick had and we can see he did a stall and... So some of these comments about low, slow and steep turns scare me. Everyone is cooking with the same recipe expecting different results..

[Av8r3400]

The standard wing on the K5 is kinda scary as it’s what Nick had and we can see he did a stall and... So some of these comments about low, slow and steep turns scare me. Everyone is cooking with the same recipe expecting different results..

There is nothing "scary" about the standard Kitfox wing. There are thousands of them flying and doing incredible back country and STOL operations. Any wing will stall when put into the proper situation.

[airlina]

Yea, hence the need for some speed as the fuel mileage gets better the faster one goes.

The standard wing on the K5 is kinda scary as it’s what Nick had and we can see he did a stall and... So some of these comments about low, slow and steep turns scare me. Everyone is cooking with the same recipe expecting different results..

There is an old wise saying that goes "a piper cub can barely kill you!" I have 900hrs on my Series 5 wings, and there is nothing scary about it. As I have stated before a pilot has to know his equipment and limitations. This comes from proficiency and practice and challenging oneself to become better on every flight. Bruce N199CL

[896tr]

I think my 300 horse power auto motor post was misunderstood. Won't horse power get to the point where it is a useless waste of fuel and weight for the task at hand? The Kitfox is what is, a low and slow FUN to fly airplane with very few accidents or incidents caused by design. Yes modifications can be made but how far from original design is asking for failure. And will insurance pay for any private or sport pilot when they have a controlled or uncontrolled flight into terrain as a test pilot. Just my rambling thoughts.

[Rik]

There is nothing "scary" about the standard Kitfox wing. There are thousands of them flying and doing incredible back country and STOL operations. Any wing will stall when put into the proper situation.

Apparently you missed my point. Everyone is bragging about low, slow and in close encounters with terrain doing hammerhead maneuvers, and other risky flying. The wing is not the problem, rather it’s the nut holding onto the stick that is the problem.

To site a hard fact, look no further than the Trent and Nick filming day. One wing allowed the maneuver and one didn’t.

[Rik]

I think my 300 horse power auto motor post was misunderstood. Won't horse power get to the point where it is a useless waste of fuel and weight

Yes, you will hit a wall where fuel burn starts to burn your wallet, and the incremental increase in speed is minute to the amount of fuel burn. Look no further than Mike Patey’s wilga. He has over twice the hp of a normal wilga and he’s still operating within the same VNE.

Yet the hp can get that heavy bird up and down faster than a Kitfox can in the same distance.

Hence the STOL drag results and my thoughts. The beauty of an Allison is that I can merely replace the compressor with one from a C18 and loose 100 hp and the fuel burn and then when wanted swap back.

[jiott]

I think we are doing a disservice to Nik and the rest of us by a few folks assuming he stalled in his tight turn close to the ground. That is not necessarily true. As I posted several weeks ago, I have done some tests with my SS7 standard wing to explore this exact scenario but I was at 5000' for safety. Quoting my post:

"I have tried speeds from very slow to 90 mph and then suddenly pull hard elevator in a steep, 60 to 70 degrees, turn. I could not get it to do an accelerated stall. It would always whip around very quickly and lose speed quickly while the nose would drop and put me into a fairly steep spiral dive. Nothing I could do with elevator or rudder would keep the nose even close to level. It would spiral down, NOT stalled, and could be easily flown out of the spiral at any time. Now I am no test pilot and maybe there are ways to stall it in this kind of maneuver, but I could not do it. Bottom line to me, it seems like an extremely safe aircraft that wants to naturally keep itself flying. But I got to thinking about Nik's accident, where he appeared to make a very steep abrupt turn low to the ground. In this condition your nose WILL go down even if you are NOT stalled, and there may not be enough altitude to recover."

Let's wait for more info before we jump to conclusions.

[Av8r3400]

To site a hard fact, look no further than the Trent and Nick filming day. One wing allowed the maneuver and one didn’t.


I don't know what "hard fact" you are referring to. Nothing has been stated about the cause of Nikk's incident. We do not know what maneuver was being performed by Nikk or if is was similar to something that Trent did with his plane.

Again, you are making an inference that Nikk's wing or aircraft was somehow not capable of a maneuver that Trent's aircraft had just performed. There is not enough information to make this statement, much less calling it a hard fact.

No one will argue that the STi wing will out STOL the standard wing. However, stating that the standard wing is "Scary", unsafe or incapable of amazing STOL performance is not accurate.

[Rik]

I think we are doing a disservice to Nik and the rest of us by a few folks assuming he stalled in his tight turn close to the ground. That is not necessarily true.

I’m absolutely not knocking Nick. The faa report points to a stalled spin doesn’t it?

Discussion away from Nick.. For those non pilots out there watching the YT videos and listening to certain narrators, one can get the impression that these these are the perfect planes. They stall at 35 mph, can land in 100’ and according to the videos can put put down onto any surface that’s not vertical.

They show pilots doing rolls and very steep turns down low. Then a lot of owners on here back up that pilotage with their own comments/experience of similar behavior.

I’ve got my own minimums and yes this seems exciting and roll a coaster fun but I have in the back of my mind all the time that that ground and me in this plane do not need to meet unless I say so and I act accordingly.

Back to Nick, being he’s one of the cowboys, trents friend and the fact that he seems like a real nice guy, everyone is putting gloves on and I understand that but we have to realize we are all human and **** happens. Down draft, wind shift and who knows what else but we cannot ignore the severity nor safety this stuff involves.

[Rik]

I don't know what "hard fact" you are referring to. Nothing has been stated about the cause of Nikk's incident. We do not know what maneuver was being performed by Nikk or if is was similar to something that Trent did with his plane.

Again, you are making an inference that Nikk's wing or aircraft was somehow not capable of a maneuver that Trent's aircraft had just performed. There is not enough information to make this statement, much less calling it a hard fact.

No one will argue that the STi wing will out STOL the standard wing. However, stating that the standard wing is "Scary", unsafe or incapable of amazing STOL performance is not accurate.

Your RUNNING with your own thoughts here I feel. I’m not saying the wing is unsafe at all. I’m saying for the slow, steep stuff the STI wing on trents plane is better than his old wing in Nicks plane.

Please don’t read into it what I’m not saying.

[Slyfox]

OK, I'm writing this to make sure nobody thinks I'm careless and reckless. years ago I did a huge back country flying class. I rented a Cessna 172 and the instructor had over 20000hrs. we went into the cascades and had people flying over the top of us as a command post. there were several airplanes participating. He was teaching me a bunch of great stuff. things like run along the right side of the lanes in the mountains we called it on the right side. that way as we wanted to make a left turn we could see into the area before turning into it and it would allow us to get out if needed, more room to turn. we stayed within 20 ft of the sides of the canyons with many feet below us. read that up off the ground several feet but close to the canyons. he demonstrated and I did what he called a hammerhead wing over, with a Cessna . read that Cessna, that was for when we did get in a bad situation you pull up and use aileron and rudder away from the cliff, it was amazing how quick you could turn back with hardly any reduction in airspeed and come out at the same altitude. very safe. better than plowing into the ground by far. don't think I do anything unsafe. not what I was saying. above all, get some training in the back country. don't go back there and teach yourself. I also got a bunch of ground school with this class. good , day.

[Rik]

I agree with everything your saying. We all have our personal minimums and fly accordingly.

As of yet, I’m not a bush pilot, just conveying my observations of the sport and admiration for the flying it requires. It goes against all teachings to a degree and as your the first to point out, get training.

My mission, yet undefined 100%, is not cast in stone. I need some speed to get to some place whereby if I wanted to follow your flying environment, I then need a plane that can handle the mission while I’m having said fun, then I need some speed to get back home.

150’ takeoffs and landings are not required for this mission, however, building a STOL drag plane they would be. Then again since it’s only aspirations and wishes at this point maybe having two sets of wings would accomplish this goal too.

I’m merely doing my due diligence at this point. My goal would be to get/modify/build an S7 or S7STi and use a more than adequate power plant to achieve this goal. With my resources I can do things slightly differently than or different than others have considered.

As I’ve stated, a KF might not be the plane but one has to do their research.

[DesertFox4]

Sounds like good training Steve. Mountain and back country flying takes a set of skills not taught in most flight schools.

[Av8r3400]

I'll second that, Steve. My time spent with Paul at Stick and Rudder was invaluable. I am hardly a "mountain" bush pilot, I have barely scratched that itch, but Paul's teaching has allowed me to safely experience the element and begin to learn.

I hope to do more this summer...

[DesertFox4]

Hope you can Larry. I’ve flown with Paul several times adding up to 10 or 12 hours now and learn something substantial every time.

[Slyfox]

one thing I did last night, I looked at my kitfox log books. In the front it said model 4 STOL aircraft. Yes the standard kitfox is classified as a STOL aircraft according to my log book. I personally believe that as well.

[DesertFox4]

Every Kitfox produced from 1984 until now is a STOL aircraft with only one exception. :) Come to think of it, it was pretty darn capable too although, not sand bar capable maybe.

16606

[aviator79]

Every Kitfox produced from 1984 until now is a STOL aircraft with only one exception. :) Come to think of it, it was pretty darn capable too although, not sand bar capable maybe.

16606

I see where you are going with this. Why choose between standard and STi, when you can have both?

[Rik]

How many of you have wheel pants?

[kitfoxjim]

Rik, with that engine are you perhaps plotting a Draco killer? With the right prop that can provide some braking, it might be possible!!

[Rik]

That’s very optimistic as they have literally thousands of hours ahead of me so that’s fantasy for me. It would be honorable just to qualify.

I have an Allison C250. Essentially look at any bell jet ranger and you’ve seen one in action. They make about 420 and I’m making like 450ish.

I can change the compressor down to a c18’s and loose 100 hp and the corresponding fuel burn.

[Flyboy66]

Yea, hence the need for some speed as the fuel mileage gets better the faster one goes.

The standard wing on the K5 is kinda scary as it’s what Nick had and we can see he did a stall and... So some of these comments about low, slow and steep turns scare me. Everyone is cooking with the same recipe expecting different results..


I am not familiar with the C-250, so I don’t understand your comment about fuel mileage improving with speed. My aviation experience is based a model that states drag increases exponentially with increase in speed. So, the only way to make an aircraft go faster without increasing fuel consumption is to reduce drag by changing the airframe.

I did look to see what a C-250 is and saw that there are many variations, and I have no idea how much power you have available.

I think that you would experience many problems with any engine that has significantly more than 200 horsepower. First is fuel burn as others have stated. Draco is a flying fuel tank after being modified. The Kitfox only has 27 gallons, which with any turbine engine, goes very fast (example: BD5-J, tiny engine, huge fuel flow).
Even if it had 50 gallons, it is unlikely you could get very far and still have fuel to play with.

The Kitfox was designed for about 100 hp. If you strap on 300 hp and cob the power, I am not sure if it has enough control authority at low speeds to keep you from doing an aileron roll during a go around.

Next: weight. Turbine engines are more efficient (power to weight ratio) than piston engines, but your engine is probably pretty heavy. And with that much power, it will also need a fairly heavy propeller system to absorb the power, so it probably going to need ballast in the tail to keep it in limits. It also looks longer than a Rotax, so the weight would likely be much further forward further aggravating the CG issue. Will you even have available payload to have someone in the other seat?

Edit: just thought if another potential problem with the C-250. Does that engine have a gas generator and power turbine like the PT-6, or is it a single shaft engine with direct drive off of the gear reduction (like a Garett TPE-331)? If it is a single shaft setup like a Garett engine, you will most likely need a prop that stays in flat pitch during start up, and I don’t know where you can source one in the diameter that would be appropriate for a Kitfox.

If you can get around the 1550 lb gross weight, I think the other issues can be solved by limiting the power and adding fuel capacity. The airframe can only be dragged through the air up to Vne. But, with a turbine, you get much better economy with altitude, and the TAS increases relative to the IAS, which would be you limiting factor (Vne.)

[Rik]

With any turbine your going to be sucking fuel regardless of output rpm the variance between the extremes is far less than what one would expect. Example, if your fuel burn is 18 gal/hr at 80 mph but only 20 gal/hr at 120 then its a no brainer to run at 120 instead of 80. Your running it to the lean extremes so to speak as the faster you go the law of % makes you more efficient. Fuel capacity is a concern for any distance however. Max fuel burn is about 24 gph worst case but that on a 5 minute take off rating.

Your backwards on your power to weight ratio. reciprocating engines grow in weight faster than a turbine. My TF50 is only 628 lbs, my T58’s are 328 lbs and so on. I’m far from a novice when it comes to turbines. The Allison is about 158 lbs.

I’m more concerned about a steep full power climb out and having aileron authority to keep it from doing a spiral climb. In a turn there’s no reason to be at full power to have that as a concern.

[Flyboy66]

If you are correct about your fuel burn assumptions, then your statement would be correct. However, your speed increase is 50% in your example, so your drag would increase 225% which would require more than twice the power. Although engines have a sweet spot that they were designed to operate in, I don’t know of any that would give a 225% increase in power on a 11% increase in fuel burn. The fuel flow vs power curve would tell you the optimum power output of the engine.

By the way, the speed of these kits is dependent on configuration (not insulting your intelligence). The guys getting 95 mph are running Cabane gear (more draggy than Grove spring gear) and are also sporting 26” or 29” tires.

Who has wheel pants on their planes? Only those with the 600 x 6 tires.

[Rik]

If 100 hp rotax will get the plane to 120 mph then your assumptions of power needs are off dramatically as the 100 up rotax only produces about 75-80 hp in cruise which is no where near 225% increases you speculate about that would be need to reach the top speed from 100 to 120. Your assumptions would equate to 180hp to reach 120.

However, the fuel burn in turbine is not necessarily a power rating as it is the crappy efficiency at non full power. The turbine will idle at about 13 gph and I don’t think my assumptions are that far off.

[Flyboy66]

Ask the guys with the 912uls what they are getting. I think I just saw a guy post that he got 120mph with Grove gear and a 912 uls. Good luck with your project. It sounds like you have thought it out.

[kitfoxjim]

It's fun to think about what it might take to beat Draco in the STOL Drag races.
Rik's turbine with that weight has a superior power to weight ratio.
Standard wing KF is faster than Trent's. With the available power, acceleration to Vne will be quick. Beta prop deceleration at the line could be the deal breaker. Again there is plenty of power with timing being everything.

The overall power to weight ratio compared to Draco should be a distinct advantage.
Big tires would enable a larger diameter prop, but might require some positive thrust angle to counteract drag, but this would also help during heavy deceleration!
The airplane would be pretty much a purpose built machine, maybe not practical for everyday use, but I think a capable competitor!

[Rik]

Thanks.. a purpose built plane is just that, purpose built.

I’m thinking outside what some would think is normal and an even further outside would be having the ability to reconfigure the plane for certain missions.

Small wheels and fairings for travel, large wheels for other missions, smaller motor when power is not needed and of course the big one when power is needed. These are all bolt on and take off things. Some work involved yes but the attraction to the “Experimental” is this ability to make changes. Some ideas I don’t want to even mention as I don’t need to have people stand upon their soap box and preach just because they do not have the knowledge/experience/desire to achieve certain things.

Seriously, my only reservations about a Rotax are that the new turbo one is going to be a $50k item in the plane if not more. I think it’s an absurd amount of money plain and simple for what your getting. If I’m going to spend that then I can spend x instead and have something for the cost.

[aviator79]

I don't think any comments you have gotten here come from a lack of knowledge, experience, or desire. All I see is frank discussion of the topics you asked about.

Get on it. I'm sure we'll all be interested to see how it turns out.

[Rik]

Thanks, but I still haven’t decided on a plane yet..

I need to do a lot more research first.

[Clark in AZ]

Maybe take a look at the Bearhawk Patrol? VNE 165, cruises at 150+, lands at ~35, holds 55gals of fuel. Might be a good fit for your engine?



https://bearhawkaircraft.com/patrol-specifications/


Clark

[Esser]

I think a regular bearhawk is the ticket. I would only do what you want to do on a Kitfox if you stretched the fuselage an extra two feet. You’d need a large fuel tank behind the pilot seat for an extra 30 gallons.

I don’t think the Kitfox is the plane for a turbine. Sorry to be a kill joy.

Anytime you do something like change an engine, you are supposed to put it back in he flight test phase.

[Flyboy66]

I am not sure if you were referring to me with the soapbox comment, but I don’t think I ever told you it wouldn’t work. I was only stating the problems that I thought you might encounter with your project if you decided to move forward with it. We obviously disagree on your power, speed and fuel flow statements, but I haven’t operated your type of engine, and you haven’t built the plane, so we don’t know if either of us is right or wrong.


I am not the most experienced guy on this forum, but my comments weren’t made without some life experience. I am familiar with turbine engines. I have over 4000 hours behind TPE331’s, 1200 with PT6’s, 500 with PW119’s, 975 with JT8-D’s, 11000 with CFM56’s and similar with IAE V2527’s.

If you want to refute or explain why the things I said were invalid or that you have a “work around” for them, then I am sure it would be interesting reading for everyone. Draco is a prime example of what creative problem solving can accomplish. The beauty of experimental aircraft is that you can make them what you want them to be.

I believe that the recommendation from the others regarding the Bearhawk is spot on for what you are trying to do, and that it would have far fewer snags than the Kitfox would have.

Whatever you decide, I would love to follow your progress, so keep us posted.


Steve

[Slyfox]

since it appears you have unlimited money. maybe. Why not build two airplanes, one just for the turbine and for competition. the other for fun flying into the back country. I have two. one for cross country and one for back country.

[redbowen]

Rik, your original question is about how much HP can a Kitfox handle, assuming a model 5-7. It has options from the factory, tested up to 180hp with the Titan 340 install. As others have stated, hp above the standard 100-110hp is not going to help much with cruise speed because of the drag characteristics of the airframe, but the HP will help you accelerate and climb. Adding weight to gain HP is definently a trade off. I run a Lycoming O290 130hp, but weigh about 80lbs more than a Rotax install. I love it, especially at sea level, but at high DA I cn feel the weight as the power drops off. This is the main reason that I am doing a Yamaha conversion in the future. At 150hp, without a turbo, and only 5-10lbs more than a Rotax 912, it is a great solution that has been proven to be reliable in other airframes. The new Yamaha Sidewinder with a factory Turbo that is cable of 220hp in its stock configuration would be more HP than the Kitfox can really utilize other than in a STOL Drag or STOL T/O application. So, 400+hp I don't see how you can utilize the power.

The STI wing vs standard wing: First off, you know nothing about Nikk's situation and drawing a conclusion on the cause and making a ridiculous statement about the standard wing being scary just shows how much you don't know about the Kitfox. I actually take offense to you referring to this accident to support your statement, considering Nikk is a friend of mine. The standard wing, which has a fantastic safety record and is very predictable, is on the vast majority of all Kitfox 5-7, has a stall speed around 40mph. This will vary based on weight, installation/rigging and VG's. The standard wing will cruise nicely at 110-120 and is capable of 140mph. With the STI wing you can expect a slower stall speed by around 10mph and you can expect a loss of 10-20mph in cruise speed. You will also loose some of the snappy response that the standard wing has, the STI is slower in roll response. I fly often with an STI equipped Kitfox and can definitely see the difference in STOL performance compared to my standard wing, making it the better choice for off airport short operations.

STOL Drag: Before you build a purpose built STOL drag aircraft to compete with Draco, you may want to come out and compete to see how you do. Bring whatever you fly now, assuming you do. It is a lot more about the pilot than the aircraft than you think. Especially getting into the top 16 for the finals. In the finals HP and aircraft becomes a bigger factor. If you look at the times in the finals you will see that the top two times were the best power to weight ratio aircraft, Draco and Steve's Yamaha Highlander. Trent out performed the carbon cubs and again he had a better power to weight ratio with the Turbo powered 915. The key to do well is Pilot skill, light weight, and high horse power, in that order. The turbo powered piston engines will be the future of this race at least until purpose built electric airplanes are built. That is because of the elevation that the race is conducted at. You loose 2-3% hp per 1000' of altitude, so the NA guys are loosing HP but still weigh the same. The Rotax 915 still retains its sea level horse power and that's why it does so well against the Carbon Cubs. I think a Turbo Yamaha powered light weight set up can compete with Draco. The big advantage Mike has is the beta prop. Steve Henry is going to show up next year with a 300hp Yamaha Highlander and it will make for a good race.

A turbine in a Kitfox is something a lot of us have talked about and unfortunately the fuel burn and fuel storage is going to be your limiting factor. I am unhappy with my range at 3.5 hours running the Lycoming O290, so a 1.3 hour range would be impractical for an airplane you actually plan on going out and flying anywhere. There was a guy that put turbine in a Zenith https://www.youtube.com/watch?v=w5zpjQ1lmo4 and the limited flight time made it a huge disappointment. Now you could increase the fuel storage, but now you are changing the airframe design and load distribution. It can be done right, but like others have suggested, with the type of HP you are talking about, a larger airframe would better utilize that power. Bearhawk, Backcountry Cub, Sherpa, Murphy.

If you can be mindful that you are on a forum of people that have vast experience and love for the Kitfox. They are providing you helpful information based on that experience. Some of your responses seem not to acknowledge this and can rub people the wrong way. We don't know your background, so when you draw conclusions about the design without ever owning or flying one, it lowers your credibility. That being said if there is information that we can contribute to what you are trying to accomplish than I for one am happy to do so as long as you are respectful. Experimental Aircraft are just that, experimental, I am all for trying something other than a standard Rotax 912 install.

[GMKman]

Well put Bryan!!
I love and trust the standard wing a lot especially after putting vg’s the same place you did in your video. Very docile and predictable. I personally like the faster cruise speeds of the standard wing and it lands plenty short enough for my flying taste aka dirt roads, playas, and ultralight strips.
I’ll definitely be following your Apex build intently as I’m very interested in a lighter/ economical/ more powerful engine. Win/win/win. In my book.

[Rik]

Mr. Bryan first, I want to thank you for taking the time to respond to my questions.

How this conversation gets turned around and into you, and others, believing that I am bashing on Nick is beyond my comprehension. I read about the accident and someone on here posted the FAA report. http://www.teamkitfox.com/Forums/showthread.php?t=9300&page=5. It clearly states that two planes were performing maneuvers showing the differences. i.e., Nick and Trent flying showing how one plane performs vs the other and one of the key things in my 16 yr old mind is that unfortunately Nicks plane has a different wing than Trents plane does and the results make me believe that Nicks wing might not be as good for the low and slow stuff as Trents wing is. Nothing more, nothing less.

If I’m saying something wrong, or misunderstood what is stated in the report then I sincerely apologize. I personally don’t want to meet the ground unless it’s under my control. This is why I, can only speak for my own concerns, brought this up in the first place. If one was to build a new Kitfox which wing would one want? Which one is safer for slow, low and at times steeply banked?

Now as far as the drags and some dream plan to go head to head with Draco and thinks it’s a walk in the park??? I think your running this in your mind far more than I am in my mind. I’m curious not boisterous at all. I believe in doing some due diligence if one has a thought about anything. This is the Kitfox forums so what better place to ask a question than from those with a Kitfox was my thoughts? Was I wrong there too?

I had no plans to go into details about what stupid ideas I have until someone asked.

Then I got comments and a lot of private messages about how stupid I was. “don't you know how much fuel those things burn?” and “what kinda rich F’ are you?” “your going to loose airleron control with that much power in he turns.” And several more about how wealthy I must be.. Sorry I ****ing asked.

All this from a simple question about how much power can one put in a plane.

As I’ve previously stated, the Rotax 915is just seems like a lot of coin. Nearly $50K of them in reality. I searched for answers/results about the 180 hp engine in the silver K7 but there are no results listed anywhere that I could find at least. The Rotax is a more expensive route to go so I’m curious as to what “viable” options exist out there. I’ve got a few turbines and the smallest one is the 250 which can be downsized to a C18 in 20 minutes but I digress.

One of the things that attracted me to the KF and the Just is the side by side seating. I’m just not a fan of a tandem setup. The other planes are mostly tandem seating so they are not my first preference is all and they are significantly more coin too.

I think I’ll just stick to reading instead of asking questions if it means everybody is going to take offense to my questions/ideas. Look forward to watching your videos and your conversion project.

[efwd]

Rik, don't run off so quickly. As one who communicates rather curtly, and as a result, often misunderstood, I recommend you take the suggestions and simply adjust. You must recognize that there is a significant gap in age here if your 16. There is bound to be friction, especially considering that written text often leaves out the intonation and inflections. As you have said, you have had a number of personal replies. Sit back, reflect, take another approach and acknowledge that the comments on Nikks situation fell on some raw nerves being that these are Nikks friends here. Even in light of this conversation these gentleman are still offering to answer your questions and assist you in realizing a dream. They have only requested something that certainly can be delivered on. I've been there (more than I care to be). Hang in there.

[aviator79]

Rik, if you're interested in building a plane, Kitfox or otherwise, you won't find a better group of people than you'll find on these forums.

Eddie has nailed it that it's difficult to interpret tone on a written forum. I'll say that I have interpreted your tone here as a bit brash, arrogant, and condescending, while at times demonstrating sizable gaps in your own understanding of flying, experimental aviation, and the engineering effort required to do what you suggest. Maybe I've misread you entirely.


...just because they do not have the knowledge/experience/desire to achieve certain things

Comments like this directed at people who have been engineering, building, and flying airplanes far longer than you've been alive are not helpful in generating constructive dialog about your ideas. Keep your own tone in check, and you'll find the people here are more than willing to help. Comments like "Don't you know how much fuel those things burn", and "you're going to loose aileron control with that much power in the turns." aren't personal attacks. They are comments and questions of a technical nature that directly address valid issues with the project you're proposing. Not all ideas are good ones, and if someone thinks what you're doing is a bad idea, they would do you a disservice by not telling you so. Assuming your age is not a typo, you're not even old enough to hold a Private Pilot certificate for airplanes. Consider that the people on this forum have a lot of knowledge and experience that you do not. You can choose to benefit from their experience, or you can write them off as naysayers. That's up to you, but don't lob underhanded insults.

As to the cost of the 915iS? I agree that the install is too expensive to be worthwhile for most builders. However, I think if you go ahead with your turbine project, your total cost will not be dramatically less. Developing your own firewall forward from scratch will be expensive and time consuming.

[NinerBikes]

Rik,

I am in "Theory" mode here, just studying for a Sport Pilot license.

I also am probably undiagnosed Asperger's, or high functioning Autistic, so, I too, may come across as opinionated, brash and or arrogant, despite it never being my intent.

Sit back, slow down, if you are only 16... get some real world experience under your belt, as soon as you are able to, before you start contemplating maximum limits on a KitFox build.

It's always a good idea to learn to crawl, before you learn to walk, let alone run at top speed, at the max engineering limits. In due time.... In due time.

I, myself, am thankful there is a BB to participate in here, to learn from the masters of Experimental builds. Someday, who knows, I may get to fly with one of them.

Perception is everything with the folks here... many nuances are missing both texting and emailing, as well as posting here, vs face to face talk. I've not mastered it, so I try to tread veeerrrry carefully.

It's OK to ask questions, always. But.... you must sit back, listen, and keep an open mind, not anticipate the answers you expect to hear.

Good luck in your quest for knowledge, there's many wise old owls here... try respecting your elders, it will take you a lot farther, if you choose to do so. Practice patience.

No one knows what Nikk did, unless you were there, and you saw what happened. Trent didn't even see what happened.

I can look at trend analysis.... I can say that Nikk likes to do steep, tight turns, at least when the camera was running on him, for video's. I can tell you that no matter how much lift your wings generate, the steeper the bank, past 45 degrees, the amount of lift you get from any pair of wings gets reduced exponentially, that, unless offset by corresponding thrust, that's not going to happen in a KitFox powered plane, but might happen in a fighter jet, you are going to lose altitude fast in that steep, tight turn. Can't break Newtons Laws of apples, and gravity.

But that's the theory.... No one here actually saw what Nikk actually did. So speculation is greatly not appreciated by his friends here, because no one really knows what happened. Other than looking at photo's and angle of impact, we have no facts. Without facts, it's all speculation. I choose not to speculate. I'll read the NTSB report, maybe the final FAA report, because those folks are the experts that can measure everything, and they WERE there for the aftermath.

[redbowen]

Rik, no worries, didn't want to discourage you from asking questions here.

You did strike a chord with talk about Nikk's accident, but I will leave that up to Nikk to share when and if he feels like it. I will say that Trent was landed on the ground at the time so there was no maneuver that Nikk was trying to do that Trent had done, and I only mention this because I don't want you to make a conclusion about one wing vs the other based on the FAA report. Both wings are exceptional.

You really just need to decide where you want the compromise. Usually the best way to decide is to look at what 90% of your flying will be, STOL or cruise, ect. For me my mission has changes many times over the 12 years that I have had my fox and the wonderful thing about Kitfox is that it can be modified as your mission modifies. I spend 80% of the time solo doing off airport flying and the other 20% I take one of my kids or a friend and do 3 or so long x-country trips a year. On x-country flights I love the standard wing and 110mph with bushwheeels, but on short final to a 200' gravel bar or a mountain top at 9000'msl I am wishing I had the STI wing. Aeronautical design is all about compromise. Then along comes a project like Draco that makes you think there are ways to have the best of both, but it takes an amazing designer (Mike) and some substantial funds.

Having an idea is the start to all innovation, so run with it. But during your design planning you might run into a hurdle that can't be overcome. These hurdles sometimes lead to new and better ideas. For you to be dreaming up these projects at your age is fantastic. I don't know what your source is for your turbines, but check out the Solar turbine, it is an APU unit that has been adapted to the Helicycle mostly, put the power to weight ratio is awesome and the size would work great in a Kitfox. You still have the fuel burn issue.

If you want more info and specs on the 180hp Titan engine set up, you should call John at Kitfox. They really haven't promoted it much and I think it is because the Rotax 915 is just a much better fit. I agree that it is just too much money. That is why I like the Yamaha option.

Find someone local with a Kitfox and see if you can get a ride.

[Slyfox]

Rik, wow 16 years old. All I can say is, reverse that and you have my age. OMG I let out my age, oh boy:eek:

[NinerBikes]

As an aside, has anyone yet put in a Yamaha Apex1 FI motor from a snowmobile into a Kitfox? Supposedly 150 HP easy, with reasonable cost, compared to a 914T or 915, or even a 912 ULS.

Steve Henry does run one in his Highlander, and did do quite well with it, time wise, in the STOL drag races at Dead Cow STOL drag races in 2018.

Thoughts?

[Esser]

Search YouTube apex Kitfox. My friend rick has one in his modified STi. He’s waiting for his final inspection so it hasn’t flown yet.

[brjohnso]

Lots of people have put more horsepower on a Kitfox, including the factory, but none of those options has every become popular, and for good reason.

The 100hp rotax is incredibly light, efficient, and reliable, and provides all the performance needed by 90 percent of the people out there. For the remaining 9.9%, an Airmaster prop, and/or a 914 Turbo provides almost more power than you can use on the Kitfox Airframe.

More power won't make a Kitfox go faster. Vne is 140mph, which I believe is about the limit of the fabric on the wing. Vno (bottom of the yellow arc) is 108 I believe. Climb rate might improve, but it will definitely reduce useful load, range, and fuel economy. Climb angle is actually more important, and the increased weight of a bigger engine will reduce the potential benefit of the increased power.

If you want more horsepower, I think you should look at the Rans S-21 or S-20 with the 141 all-metal wing. It's a much better fit for that class of engine. It has a much higher Vne and will cruse at 155 all day with a 915 or a titan. Fuel capacity is also much greater so it can feed that bigger engine.

[jmodguy]

If you want to be like everyone else then by all means stick a Rotax on the front and call it good. If you want to be different and/or have the skill to tackle a complex project then do something different!
Range is not a concern for 99% because our bladder or butt won’t sit that long.
Going faster is not the issue. Everyone knows what the airframe limitations are.
It’s all about performance.... Yes some of us want to hot rod our Kitfox!
Build it, document your performance and let the group know what you found. The purpose of experimental aviation is to learn something. Kinda hard to do if you repeat what everyone else does...

[jiott]

Jeff, I agree with all that you said; however I would like to point out that probably 95+% of us on this forum are not really the kind of "experimenter" that you are referring to. Most of us just want a well engineered, safe, good performing, efficient, reliable, easy to build airplane. We have found that in the mainly standard Kitfox, and it so happens that it is designated "experimental". We like that because it allows us to make more or less minor changes to personalize our aircraft. Because of this you must forgive our comments and advice that appears to you and a few others as stodgy and not very cutting edge. We are just speaking to the majority of folks who follow this forum. Don't get me wrong, I enjoy hearing from those who are truly pushing the limits and adding to the knowledge base for all of us. :)

[NinerBikes]

Vne is expressed in mph, not kts?

[NinerBikes]

If you want to be like everyone else then by all means stick a Rotax on the front and call it good. If you want to be different and/or have the skill to tackle a complex project then do something different!
Range is not a concern for 99% because our bladder or butt won’t sit that long.
Going faster is not the issue. Everyone knows what the airframe limitations are.
It’s all about performance.... Yes some of us want to hot rod our Kitfox!
Build it, document your performance and let the group know what you found. The purpose of experimental aviation is to learn something. Kinda hard to do if you repeat what everyone else does...

I would suggest, also, that Experimental is a way to keep your expenses down while being able to afford to fly... by doing your own maintenance, checks, 100 hours, annuals, whatever. Everyone's needs and missions are different. I'd be happy as a clam in a used SS5, 6 or 7 with trike landing gear. Who knows, maybe even in a Van's RV-12, too.

[brjohnso]

What are you trying to accomplish? Significant improvement in performance (beyond what others have already done) is probably going to require changing more than just the engine. Other components will probably have to be changed to take full advantage of that horsepower.

[Esser]

Yes, for some reason the experimental crowd loves mph instead of kts.

Fabric isn’t the limiting factor for the Vne. It’s flutter on a pretty flexible wing.

I don’t have much time on my plane but at 75% power I’m cruising at 128mph. 914 with fuel injection and CS prop.

[jiott]

Not having been a pilot previously, when I started flying my Kitfox with a Dynon Skyview panel I went back and forth with setting speeds and distances in knots or mph (the settings are easily changed). I finally chose the mph since that was what I was familiar with. I guess I'm not a "real" pilot, but at least I can relate to it.

[rv9ralph]

I have been associated with experimental aviation since the 90's. I have found that most that have tried engine conversions (those that have not been extensively engineered for aviation) spend most of their time working on engine issues and not flying.
The other thing...

Fabric isn’t the limiting factor for the Vne. It’s flutter on a pretty flexible wing.
Fabric was used on many aircraft of WWII. i.e control surfaces on F4U Corsairs capable of 400+ mph.

Ralph

[Slyfox]

kts is what ATC uses. My gps in each airplane is set up for KTS because of this. makes understanding tower and such easier. I use KTS for the rv on all accounts. the Kitfox on the instrumentation is mph. It actually makes sense. On final and up to landing with the rv in kts it backs off the reading in reality to the kitfox 15%. so going back and forth in aircraft I'm a little closer in my reading coming in to land. you may not understand, but it really does work. if I hit 70 in either airplane on final, I'm pretty close no matter which one I fly. over the numbers I want 62kts in the rv, 50mph in the kitfox. works for me. but the gps having Kts on both really works, that's what atc goes by. also, both aircraft has the steam gauges for airspeed. so, I just glance and see a pointer in the right area mainly. works for me. Oh I have the dynon d180 in the rv. I never use it to land. hate it. steam all the way.

[Av8r3400]

Vne is expressed in mph, not kts?

Yes. It's an airplane, not a boat. :D

[Rik]

I would suggest, also, that Experimental is a way to keep your expenses down while being able to afford to fly... by doing your own maintenance, checks, 100 hours, annuals, whatever. Everyone's needs and missions are different. I'd be happy as a clam in a used SS5, 6 or 7 with trike landing gear. Who knows, maybe even in a Van's RV-12, too.

You will like the RV12. I have about 60 hrs in one. Super easy to fly, super easy to land can handle a decent cross wind.

[Slyfox]

this is my opinion and also I am biased. but if you want a bad boy that can land in some good cross wind you build an rv7. If you want a slow airplane to have a bunch of back country fun you build a kitfox. there you have it. I have 1300 hrs in the rv7 and about 2000 in the kitfox. no way I would do an rv12, my choice is the kitfox.

[Rik]

Agree but I’m not certain he has a license yet and the 12 is a very easy plane to fly and possibly even learn in with their SLSA model.

They’re a lot better than a piper 140. Guess if he’s going for a Sport license then the 12 can fulfill that too.

[NinerBikes]

Yes, the Sport License now is what I am studying for... ground school, first. Not too easy to find a Kitfox to get a ride along in, here in Southern CA. RV-12s,, probably a lot easier to find a ride along in.

It's a height thing, I am 6'5" tall. Got to fit in it comfortably, for a few hours perhaps.

[Rik]

Well your flying lessons will have to be in an SLSA at the minimum. Kitfox builds them but as you’ve stated finding a KF at a school will be hard unfortunately.

You can fit in a 12 I believe. They are super easy to fly and most all of them have a glass panel which I feel is a plus.

[aviator79]

this is my opinion and also I am biased. but if you want a bad boy that can land in some good cross wind you build an rv7. If you want a slow airplane to have a bunch of back country fun you build a kitfox. there you have it. I have 1300 hrs in the rv7 and about 2000 in the kitfox. no way I would do an rv12, my choice is the kitfox.

I agree with rhis. The RV-12 is too easy to outgrow. There was an article by the owner of Van's Air Force recently where he was trying to make the case for a "Van's super cub". He talked about flying over spots where he'd see high-wing taildraggers camping, and longed to be able to do that. The choice between an RV-7/9/14 and a Kitfox is about whether or not you want a cross-country machine, or a backcountry plane. But what's the mission of a 12?

The RV-12 is just a slow RV. Our Kitfoxes are slow, but we trade that speed for backcountry capability, amazing cockpit views, and a really fun airplane. I get that NinerBikes wants to keep it LSA, so it's a no-brainer in my opinion. He'll quickly get bored of the RV-12. In terms of a school that flies Kitfoxes, that's easy-peasy. Look in the adveriser's pane over there. <------.

S&R will do an accelerated course. Well worth it IMO.

[jiott]

Regarding crosswind landing capability, don't sell the Kitfox short. I took my training for Sport Pilot with S&R in Boise, which can be a windy place. Early in my training I was up with Paul Leadabrand in the SS7 and when we were done the wind had picked up considerably- about 30 mph mostly crosswind. I was not ready for this so Paul landed it in that crosswind forward/side slipping it and touching down on one main and the tailwheel easy as pie. His comment was he would never attempt that in a super cub (which he teaches in occasionally) but the Kitfox can handle it "if the pilot is capable". The 18 mph crosswind limit given in the Kitfox SLSA POH is VERY conservative according to both Paul and John M.

[Dave S]

Jim,


Your story is what I understand to be true about the KFs XW landing capability. :)



A person considers that we have a lot of roll authority with the long flaperons and a darn good rudder. Most of us trained on aircraft with simple alierons which get pretty soft at landing speeds on most aircraft.



Couple the roll and yaw authority of a KF with its high wing configuration makes it an airplane that can be pretty controllable in a straight crosswind.



I think the greater issue most of us run into is a strong XW is often very gusty too.



Pilot limitations/experience/confidence factor into what a person wants to try CX with a KF - the aircraft is very capable.

[Slyfox]

I have no problem landing with a strong cross with a kitfox. harder with my 4 I'm sure because it's up to 300lbs lighter than the newer kitfox. but the taxi back to the hangar is the *****. now with the rv, I never do a wing high landing, always a crab like the big boys. on landing I use rudder to straighten and I've done this with over 25k direct cross with a bunch of gust. the kitfox, ha, I've always went cross runway and into a taxiway off the runway, but like I said. a ***** to taxi to the hangar. :eek:

[Esser]

I concur. I’ve been landing in 15Kts gusting 20 or so. Landing is no issue but taxiing is

[Slyfox]

I look back at all these things that came up in this thread. Big engine, type of plane, cross winds, training. you name it. but one things that has not been brought up, "PILOT SKILL". Doesn't matter what you put into that plane or what plane. That PILOT SKILL is the most important. Building that super plane ain't gonna cut it if you don't have PILOT SKILL.

[airlina]

AMEN Brother! Bruce N199CL