Making my series 5 into my dream plane

[trentp]

Hey guys, I recently (5 months ago) purchased a series 5 kitfox as my first airplane. I was (am) a low hour pilot with no tailwheel experience at the time, but after tons of researching and reading I knew a Kitfox was the plane for me. I found the plane on barnstormers and was instantly attracted to its equipment list. It was powered by the 912ul with Xtra High Compression pistons so we think it was right around 90-95hp. It had the IVO in flight adjustable prop with constant speed controller so the airplane was a real performer at sea level. Unfortunately for me my field elevation is over 5000ft and hot in the summer so its not uncommon to see density altitudes well over 8000. I quickly got the itch to start upgrading the plane and am now well under way.

Here I am, the proud new owner of what I am calling the FreedomFox
http://www.teamkitfox.com/Forums/picture.php?albumid=440&pictureid=5370

All fueled up and ready for the 23 hour flight home from Memphis to Reno
http://www.teamkitfox.com/Forums/picture.php?albumid=440&pictureid=5371


The first thing I ended up changing was the prop. Although I loved the performance of the IVO, it always had vibrations and the wiring wasn't perfect so I ended up with a fixed pitch much of the time (found the wiring issues upon removal of the prop... figures). I swapped to a whirlwind GA-70RW, I knew it was a little too much prop for the plane but planned on adding horsepower so I figured it was better to get the wide chord over the razor version. We pitched the prop for takeoff so I ended up losing a good 15-20mph in cruise, but man, this prop was SMOOTH!!!

This whirlwind prop is just beautiful!
http://www.teamkitfox.com/Forums/picture.php?albumid=440&pictureid=5360

The next thing that had been bugging me was the panel. It had tons of gauges which is nice but also had a Dynon D-6 which was a 6 in 1, so many of my gauges were redundant. Also, I was using an iPad Mini for navigation and where the mount was for the iPad had it covering much of my engine monitor gauges and breakers, which wasn't ideal. Luckily I have a good friend with a CNC router so I ordered some carbon fiber plate and got on my computer and started drawing. I ended up using a flypad mount on the left side to hold my iPad mini, and mounted my steam airspeed indicator in the back of the mount (iPad covers it but in the event of a power loss or if the Dynon dies I will still have airspeed).

The old panel
http://www.teamkitfox.com/Forums/picture.php?albumid=440&pictureid=5357

As you can see with the iPad mounted it turned into a vary clustered panel
http://www.teamkitfox.com/Forums/picture.php?albumid=440&pictureid=5359

Out with the old
http://www.teamkitfox.com/Forums/picture.php?albumid=440&pictureid=5361

The old panel cutouts helped for measuring all the holes to be cut in the carbon
http://www.teamkitfox.com/Forums/picture.php?albumid=440&pictureid=5363

Ready to cut!
http://www.teamkitfox.com/Forums/picture.php?albumid=440&pictureid=5362

Faces mounted up and ready to go in the plane, rim painted black
http://www.teamkitfox.com/Forums/picture.php?albumid=440&pictureid=5364

New panel is in! Here you can see where I put the airspeed indicator incase of a power out
http://www.teamkitfox.com/Forums/picture.php?albumid=440&pictureid=5365

With iPad mounted
http://www.teamkitfox.com/Forums/picture.php?albumid=440&pictureid=5356


While saving for more upgrades I decided to sell my other toy, my 2014 polaris RZR XP1000 which I had dumped way too much money into. By selling it I was able to get on the fast track to building my plane into my dream plane.

First thing I did was get on the phone with Hal and Jay with Zipper Big Bores and did a high compression big bore kit and slipper clutch. The plane already had a skytec starter so the slipper clutch was the only thing I needed to add aside from the big bore kit. Right away the performance was impressive. We had to add 2 degrees to the prop to keep it from over speeding, so I got back about 12mph in cruise. Also my ground roll was noticeably shorter and my climb was about 500fpm more :) I have been getting about 1000fpm with two guys and full tanks at a density altitude of 7000ft

The new cylinders have a lot more fins giving better cooling properties
http://www.teamkitfox.com/Forums/picture.php?albumid=440&pictureid=5367

Size comparison from the original 80hp bore to the new bore
http://www.teamkitfox.com/Forums/picture.php?albumid=440&pictureid=5368

Pistons and cylinders mounted on the case
http://www.teamkitfox.com/Forums/picture.php?albumid=440&pictureid=5369

The next step was getting some cruise speed back without losing my climb performance, so the best answer was to go with an Airmaster propeller system with the whirlwind STOL blades on it (the first prop I bought was the speed cut). So before I knew it I had just dumped another $8k into a prop! :eek: The Airmaster systems are all custom built per order so it took about 2 weeks for them to build my system and then another week to ship from New Zealand. Which was actually nice because it gave me some time to get a feel for the performance with the big bore before adding the air master.

Out getting my tires dirty
http://www.teamkitfox.com/Forums/picture.php?albumid=440&pictureid=5375

The Airmaster arrived last week and I was finally able to find time to install it yesterday. I am going to have it weighed for a new W&B. I figured there has been so much done to this plane since the last time it was weighed that now is probably a good time to do so, especially since I am adding 18lbs to the nose. The install went very smooth, I am absolutely blown away by the quality of the Airmaster, especially after having dealt with the IVO constant speed setup, this was the real deal.

Constant speed hub
http://www.teamkitfox.com/Forums/picture.php?albumid=440&pictureid=5372

The air master really looks good on there
http://www.teamkitfox.com/Forums/picture.php?albumid=440&pictureid=5373

Fully feathered
http://www.teamkitfox.com/Forums/picture.php?albumid=440&pictureid=5374

At the time of writing this I am waiting to get the plane in to get weighed before I go fly it. I am very excited to see the results. I will be sure to post my thoughts after I get it flying.

Next thing on my list is 26in bushwheels!

[offroute]

Really nice Trent. I'm jealous that the S-LSA status prevents me from doing the Airmaster...

[rosslr]

Hi Tent - Great post! And you have been busy in 5 months! I looks like you are achieving your dream of the dream plane! I have just mounted the Airmaster also and have the same impression of the quality of this gear - it will be a little longer until I try it out though so I'm really looking forward to your posts re performance. Great job on your panel - While love the quirkiness of the 'hidden ASI (a bit like a hidden spare key), I am a little baffled as to why you didn't mount in permanent view? Love to hear your thinking on that one.

Thanks for a great story so far - you certainly don't appear to be daunted by any of the 'big' tasks! Hope the W&B goes well and look forward to more stories.

cheers

r

[HighWing]

Trent,
I like your planning and work. I learned about the Airmaster several years ago and if it was in the budget and if I was still Class IIId, I would have one for sure. The Zipper? Seriously thinking about it as well, but age and some physical issues makes me wonder how long it would be in my own hangar.

we are almost neighbors, but I am on the wrong side of the big hills.

Thanks for the posts and pictures. Looking forward to updates as well.
Lowell

[trentp]

Thanks for the compliments guys! I was able to weigh the plane today and it weighed in just 6lbs over the original certified weight, must be the weight saved from getting rid of some gauges and the lithium battery. I did a quick test flight today, I still have a bit of adjusting to do on the Airmaster but my immediate opinion is that this prop is amazing! I put it in cruise and with the throttle about 2in out from full I was indicating 100mph, and the density altitude was at 8000ft today. I have never seen my airspeed that high!


Hi Tent - Great post! And you have been busy in 5 months! I looks like you are achieving your dream of the dream plane...

The dynon has airspeed, altitude, heading, turn coordinator, vertical speed as well as artificial horizon, so I use that as my primary gauge for airspeed ;)

[GuppyWN]

A plane that nice with all those upgrades needs................ bigger feet!

[trentp]

I know... I know... I'm saving my pennies! That's the next thing for sure

[trentp]

Got my bushwheels in! I decided that the 26" airstreaks were the perfect match. So far I am super happy with them, about 7.5lbs heavier per side than the aero classic 21" tires that I had on.

Right away I can tell you that these tires are amazing! First two landings were on pavement just to get a baseline last night after I installed them. I could tell they were softer and I could definitely tell that the handling was a little different due to the extra clearance and the softer tires. Then this morning my wife and I flew up to a nearby reservoir and did the first off field landing with them followed by a nice little hike to enjoy our day off on the 4th of July. All I can say is wow... I see why there is so much hype bout the alaskan bushwheels, they soak up the bumps so nicely and roll over anything in their way. I can only imagine how smooth this thing would be on 29s! (I didn't want to carry the extra weight or lose the cruise speed otherwise I would be on 29s right now).

The plane is pretty much just what I would ask for, I am battling some high oil temps right now during climb out so my next step is moving the oil cooler or possibly going with a larger one. Then it time to go see where this plane can take me! :D

Quite a bit of difference in size, the "21s" were actually about 19" when I measured, compared to the true 26" bushwheel
http://www.teamkitfox.com/Forums/picture.php?albumid=440&pictureid=5385

http://www.teamkitfox.com/Forums/picture.php?albumid=440&pictureid=5380

Much better proportions
http://www.teamkitfox.com/Forums/picture.php?albumid=440&pictureid=5382

First time landing off field, WOW they are worlds smoother, just suck up all the bumps
http://www.teamkitfox.com/Forums/picture.php?albumid=440&pictureid=5381

My wife enjoying the cool weather after our 4th of July hike
http://www.teamkitfox.com/Forums/picture.php?albumid=440&pictureid=5378

[Slyfox]

nice looking airplane. did you loose any top end speed with the bigger tires?

[trentp]

I did, not as much as I would have expected though, it looks like I lost about 5-7mph.

[GuppyWN]

Perfect!!!

[3 tracks]

Good job Trent
Did you have high oil temps before you installed the 26 Bushwheels? The reason I asked is because I had the same problem. My plane had the 26s installed new just before I bought it. I flew it for a couple of weeks before the weather started getting hot and there was no problem. As the weather warmed up so did the oil temp. I bought the bigger oil cooler and relocated it in front of the coolant radiator. Dropped the oil temp at least 30 deg. The CHT came up a little but there is a 1 in. gap between the bottom of the coolant radiator and the cowl. I stuck weather stripping to the bottom of the coolant radiator to fill the gap. Haven't tried it out yet.
John

[trentp]

The oil temps came up with the extra power from the big bore, the tires didn't help. I spoke with John from Kitfox this morning and unfortunately there isn't an easy fix on the round cowl. I am going to try putting a second oil cooler above the gearbox which has a little more airflow so I am hoping that will fix my problem. I am wondering if blocking that air will affect my CHTs though... I will know more tomorrow.

[Esser]

Well I personally think the smooth cowl makes the kitfox look like a much better plane...and then you would need to paint your dream custom paint job....but that's just me.

Looks like you are having lots of fun with the plane. Keep the pictures coming.

[trentp]

I agree, that was one of the options I looked into, unfortunately it's not as easy as just getting a new cowl... I would need a whole new firewall forward!

[Slyfox]

looking at the front of your plane, half the oil cooler is blocked. my answer is what I did with mine. cut the opening to give full flow threw the oil cooler. I did that with mine and did wonders. just cut the cowl. smooth the edges. it will do the oil good. also get extra air in there for the heads.

[Slyfox]

I took a quick pic, sorry for being so bad. but it will give you an idea how I did mine. gets lots of air now. http://www.teamkitfox.com/Forums/album.php?albumid=441&pictureid=5386

[3 tracks]

Sure looks like that would be a easier fix than adding another oil cooler , cheaper to.

[HighWing]

The oil temps came up with the extra power from the big bore, the tires didn't help....

I have a IV with a round cowl. Personally I like the looks better, but that is another story. I am attaching a picture of what I did for a not so effective heater in my first IV - for efficiency heater air needs to be recirculated. I think the first thing I would do if I was in your shoes is to make a scoop feeding a plenum that faced a second oil cooler similar to what I used, but as large as I could fit over the top of the spinner. Discussions on cooling when I was helping in a Lancair IV often talked about air velocity as it passes through the cooler. Conventional wisdom suggested that slower moving air picked up more heat than faster moving air. With that in mind, creating a scoop that fit fairly snugly to the top of the cowl opening then increased gradually in size until it fit snugly in front of an internally mounted oil cooler would be my first choice. it would require some fiberglass work but not impossible. I would use urethane foam to make the pattern from the cowl opening to the mounted oil cooler then covering that with several layers of epoxy wetted cloth. When that is cured, dig out the foam from the inside. It would take some time, but I thing it would look nice and be very efficient.

[Slyfox]

but his oil cooler is right up front under the gear box. having the cowl go half way over the cooler is like putting tape over the cooler. remove the obstruction and walla, cooler oil temps. simple fix.

[trentp]

Hey guys, after speaking with John from kitfox it was pretty clear that I needed to not just get more air to the cooler but I would need a larger one, since I had the smaller cooler for the 80hp engine. So I decided to try to avoid cutting into my cowl if I didn't have to and go with a larger oil cooler in a location that would get more air.

The new oil cooler is about 3 inches longer than my old one, which still wasn't very large so I decided to try running dual oil coolers. A friend of mine who is a welder came and helped me build a bracket to hold the new cooler above the gearbox. It took about an hour or so but fits nice and snug in there.

I went ahead and did a test flight (it was about 90 degrees out at the time) and found that I couldn't get my oil temps above 150, so I dropped 100 degrees by adding the additional cooler. A definite improvement but this was obviously too much so I went ahead and got rid of my original cooler, and went with only the larger one. I did another test flight and my temps jumped back up to about 180-190, still a little low but I think I would rather be too cool than too hot, now I can just work on blocking off sections of the new cooler until I get in the correct range. I was worried that I might end up blocking too much air coming into the cowl by mounting it above the gearbox like that and would see a rise in my CHTs but that wasn't the case, they held steady at 200.

So for now I am going to run it with the larger cooler mounted above the gearbox and see how it does. I am considering moving the larger one back below the gearbox and trying to make room for it but I am not sure if there is any real need to. Does anyone know if there is any reason not to run the cooler where I have it? (see photos below)

This is with both coolers, a little overkill
http://www.teamkitfox.com/Forums/picture.php?albumid=440&pictureid=5389

Here is where the new cooler is mounted, if I decide to leave it there I will get the brackets powder coated black to match the old ones. Is there any reason to avoid running it above the gearbox like this?
http://www.teamkitfox.com/Forums/picture.php?albumid=440&pictureid=5388

[Dusty]

Just. Thought !
Above the gearbox may give better airflow at high angle of attack on climbe out when I is most needed,under may be slightly blanked ?

[Av8r3400]

My plan is something like this...

[Slyfox]

absolutely, that's how mine is. except I need to finish off the cut. I haven't got around to it yet. that's how mine is going to end up when I get to it. that does work the best.

[Esser]

Trent, you waste no time that's for sure. All I would say about on top of the gear box is that if you ever want to install an external alternator, it will be in the way. Other than that I think it would be fine if you left it up there.

[Slyfox]

I installed my oil thermostat on top of the gear box. I really like the location there. to each there own. I know looks is very important to you, so I guess a double cooler is in line. should work out.

[trentp]

Hey guys, its been a while but I have been slowly chipping away with the kitfox upgrades. The latest addition, the shock monster gear from Kitfox!! :D

I figured I would post some pics of my work I did covering them before getting into my thoughts on the gear itself, it was my first time ever doing any fabric work and was far from perfect, but I figure since it will be dragging through bushes it is probably ok.

I liked the way the silver STi kitfox has its gear covered with the fairings on the actual tubes so I went the same route:

Fairings cut and set in place with Hysol:
http://www.teamkitfox.com/Forums/picture.php?albumid=440&pictureid=5775

SuperFil on the fairings to smooth the edges into the tubes on the gear legs:
http://www.teamkitfox.com/Forums/picture.php?albumid=440&pictureid=5782

Poly brush on the newly covered legs:
http://www.teamkitfox.com/Forums/picture.php?albumid=440&pictureid=5770

Painted gear!:
http://www.teamkitfox.com/Forums/picture.php?albumid=440&pictureid=5780

For the shocks I ended up with a new size that TK1 just started making, previously they recommended either a 1.5in shock or 2in shock depending on how heavy your plane is but inevitably the 1.5 was a little too soft and the 2in was a little too stiff, so they now are selling a 1.75in which is what I got.

Install was pretty straight forward, which was impressive since the series 5 does have different gear mounting points than the super sport so I was impressed that the gear legs fit perfectly.

Look ma! No gear!:
http://www.teamkitfox.com/Forums/picture.php?albumid=440&pictureid=5781

And Finally the finished product:
http://www.teamkitfox.com/Forums/picture.php?albumid=440&pictureid=5769

http://www.teamkitfox.com/Forums/picture.php?albumid=440&pictureid=5774

http://www.teamkitfox.com/Forums/picture.php?albumid=440&pictureid=5772

FLIGHT REPORT:

Ok, so now for the important part, how do the new gear perform and how they compare to the spring gear?

The bush gear sits 4 inches taller than the spring gear so any chance I had at seeing over the panel in a 3 point is gone, but the added height is great for keeping the prop out of harms way, especially in the sand and long grass/weeds. As far as the way they feel compared to the spring gear it really is a completely different beast. The spring gear is great in the way it absorbs impact, I don't know if any of you have watched someone come in and hit hard with the spring gear but the spring really does a good job of taking the hit, if I had to estimate I would say the spring gear has about 6in of travel at the wheels. The downside is that with the spring gear it takes a good portion of that energy of the impact and shoots it right back at you causing a bounce, this is where the shock monster gear is different. The actual impact will feel firm but then no bounce, even on harder landings it just sort of smacks down and is done, that, in addition to the bushwheels makes the plane a walk in the park to land, even if your flare isnt timed perfectly. Enough so that even the first real time I took out the kitfox flying with the new gear I went and landed on a hillside that I wouldn't have felt comfortable enough to land on with the spring gear just due to the fact that I didn't have the room to risk giving up to a bounce (the useable area on the hillside was about 300ft, and because of the uphill is plenty long, could still be short if you factor in a bounce or two). With the bush gear I was able to come in with confidence that I wouldn't bounce and also wasn't as concerned with the slightly rough surface of the hill.

The gear really does make bumps and rocks feel a lot less jarring, its hard to explain aside from just a complete different feel, no more bouncing and bobbing, just planted. I am completely sold on them for the type of flying I do.

The main downside I have found is the drag, I did lose 8-10mph with the gear alone :( For bush/off field flying they really do make a world of difference though, so I am willing to give up some speed to help protect the prop and the airframe when landing in the rough spots. I am going to put some fairings on the bottom of the shock tubes as well as on the "V" portion of the cabane to hopefully help reduce a little of the drag.

Some pics out in the bush with the new gear:
http://www.teamkitfox.com/Forums/picture.php?albumid=440&pictureid=5743

(that feeling you get when you can land but your friends have to circle overhead and watch):
http://www.teamkitfox.com/Forums/picture.php?albumid=440&pictureid=5766

Don't try this at home ;)
http://www.teamkitfox.com/Forums/picture.php?albumid=440&pictureid=5742

You may have noticed that my "big" 26in tires don't look so big anymore with the bush gear, so it was time to upgrade. Unfortunately my single puck Cleveland brakes were barely cut it with the 26s so I knew I would have to upgrade to something with some more stopping power to try to stop the next size up (being 29in Airstreaks). John at kitfox helped me source the best set of wheels and brakes for my application and special ordered them for me from Grove. I just received the wheels and brakes on tuesday so I went out and installed them on wednesday. I was only able to make a short test flight with the 29s but I was surprised that they didn't knock my cruise by much at all. Must be because I already slowed it down with the gear ;)

Size difference from 26in ABW Airstreaks to the 29in ABW Airstreaks:
http://www.teamkitfox.com/Forums/picture.php?albumid=440&pictureid=5785

Looks much better proportioned with the 29s:
http://www.teamkitfox.com/Forums/picture.php?albumid=440&pictureid=5784

And finally the very happy pilot (me) standing next to a kitfox with a newly improved ramp presence:
http://www.teamkitfox.com/Forums/picture.php?albumid=440&pictureid=5783

[trentp]

Next is the STi wing! :D:D:D

[DesertFox4]

Thanks for taking us all through the mod with a great write up Trent. Sounds like the combination you needed. Now a big bore engine upgrade along with the STi wing and look out back country. Looks great.

[trentp]

Thanks for taking us all through the mod with a great write up Trent. Sounds like the combination you needed. Now a big bore engine upgrade along with the STi wing and look out back country. Looks great.

Already have the big bore! So all I need is the STi wing now ;)

[jmodguy]

Trent
Thanks for the posts. Good to hear someone is doing something a little different!
I picked up a 5 project last year and am making it "my own". Fun and interesting project. Engine parts coming Tuesday...
Looking forward to your next mod/upgrade!

[AirFox]

Very nice write up Trent. I enjoyed the read and all the detailed information.

Scott

[av8rps]

EXCELLENT THREAD! Thanks for taking the time to fill all of us in on all you've done to your Kitfox 5. That is a pretty amazing conversion. Oh, and I loved the pictures flying it in the bush. What a great Kitfox.

[dholly]

Great job Trent, thanks for the update and all the super pics/vids. Right about now I'm guessing 'your' dream plane is looking a whole lot like what many of 'us' dream of too! Will be interested to hear your pirep for the STi wing.

P.S. - My wife thanks you for the new dog walking umbrellas. :)

[SSFoxBuilder]

Awesome job, Trent!

[PNWJARED]

Trent,

Really Nice write up! Thanks for sharing..

[trentp]

Hey guys, I have been doing a bunch of little tweaks and mods as of lately but wanted to update on the biggest upgrade I had done, the STi Wing!!! And then the other changes I have done since.

***I do plan on doing a review type video on the STi package but for now I figured I should update this thread.

We actually installed the wing a little over 2 months ago but I have been spending most of my time getting used to it and tweaking things to try to get the absolute most out of it, and because of that I havent posted much about it yet. I now have about 50hrs on it and I can say full heartedly that I LOVE it! It truly changes the performance of the airplane into a whole different animal, but it still maintains the Kitfox feel and is still faster than a super cub. It is a little heavier on roll at high speeds but feels just as light when you are below 80mph or so, and that's where this wing shines, it is incredibly stable at lower speeds and it definitely takes off and lands slower/shorter and the climb rate is noticably better.

When we first installed the wing I still had the stock series 5 elevator on my plane, which is a lot smaller than the series 7, so I was having trouble getting the plane to stall. Whenever I would go to stall the plane (or on landing) the tail would stall before the wing and the tail would lift so I couldnt get the wing any slower, it felt as if it was really nose heavy although the scales didnt agree with that idea. Going to the larger elevator helped a lot with getting the tail down and getting to a higher AOA for landing although I still needed to use a bit of power to get it really slow.

The next was VGs. I know that VGs dont do much on the standard kitfox wing but the guys at Kitfox Aircraft said they did get a decent improvement from VGs on the STi wing. I went with STOLspeed VGs, which I like because they are clear and go on with tape so in the event you dont like the placement you can move them or remove them all together without any real headaches. I copied what I saw a lot of my friends doing with their cubs which was placing the VGs very far forward on the wing, the theory being that they are less likely to become blanketed under the separated airflow at stall AOA. Right away I noticed that my climb rate went up and my stalls were a lot less abrupt, just a smooth break with no wing drops. With the VGs the wing is incredibly stable down almost to stall speed.

The latest change, which was the hardest one for me to swallow, was removing my 75in Airmaster proppeller and installing a 80in Prince P Tip. I have been feeling that the airmaster, as amazing of a prop as it is, isn't as well suited for the strictly STOL application as a large 2 blade. Also, since I have added so much drag, I didn't feel like I was taking advantage of the constant speed setup. So I ended up getting a second hand 80x42 prince off of Steve Henry to try out. The prince is about 15lbs lighter than the airmaster, which ended up helping a ton with me getting my elevator authority back, I can now flare to an extremely high AOA and get the plane very slow on landing because of the weight loss (maybe it was nose heavy afterall). I also lost a few MPH in stall speed with the CG shift:D . I did have to change out the gear ratio in my engine since I still had the 2.27:1 ratio that came with my 80hp 912, so I flew back out to see Hal Stockman, who makes the Zipper Big Bore kit I am running, and he installed the new 2.43:1 ratio gears that come in the 100hp. The gear change got me to the perfect RPM of about 5300 static and now this prop pulls like I have never felt. I did lose a little cruise compared to the airmaster but not a ton which is interesting, again I attribute that to having so much drag that I wasnt going to go much faster than 105mph without adding some serious power to my motor.

I am still doing my testing and getting numbers on the Prince prop but if I keep seeing the performance I have been seeing then I think I may be selling my airmaster and sticking with the prince full time.

The last of the list of changes is the T3 tailwheel shock, I have broken my tailwheel spring in the past as well as the bolts that hold the leaf spring on so I was definitely due for an upgrade in the tailwheel department. The T3 is great! Absorbs bumps really well, feels like it should handle the beating and it protects the airframe from the harsh bumps.

Onto the performance and speeds...

The interesting thing was I didnt seem to lose much cruise speed going with the STi wing, mind you I had already lost most of my cruise when I went with the bush gear and 29s. Overall I lost about 5mph or so in cruise, which put me at about 100-105mph in cruise, although I could get up to 112mph or so if I wanted to put all the power in. Compared to when I had spring gear, the standard wing and 26in tires I lost about 10-15mph all said and done with the whole STi wing and gear package.

Stall speed has been a little confusing, mainly because we changed out my whole pitot tube and hose and I am now indicating completely different speeds than before (actually indicating 10mph faster in cruise than with the old wing even though GPS says otherwise), so my indicated speeds from the old setup seem to have been low across the board including stall. I now indicate 40mph power off and 35mph power on, although when I fly in slow flight next to another plane I always seem to indicate higher than they do even when we are pacing eachother. (for example when a friends plane is indicating 40 I will be indicating 43 or 44 while we are flying at the same speed). So as much as I was hoping to have solid numbers to compare I really dont have very precise ones. What I do have is my seat of the pants feel and landing/take off distances which all say that I am stalling a good bit slower than before.

The standard kitfox wing performs amazingly well which you all know, its only when you are trying to get into the really short stuff or fly at high altitudes or heavy weight that it leaves you wanting more. My goal going into the STi upgrade was to be able to go places in the summer on a hot day that I would have previously only gone on a cold winter day, or be able to take passengers to places that I would only be comfortable solo before. I can say that I have definitely achieved that goal. The larger wing doesnt seem to care nearly as much about high density altitudes, or adding an extra person. It still feels it, but its not nearly as much as the standard wing. The way it handles at all speeds feels more locked in than the standard wing, probably due to being a larger wing, also I have noticed that the STi wing planes out much easier, so transitioning from a climb to level flight the wing just jumps onto step and is off to the races, where the standard wing would sometimes feel like it wouldnt get up on "step". The lift on it is pretty impressive. I am consistently seeing numbers of sub 200ft for take off or landing, even when the density altitude well over 7000ft. Today I did a drag race takeoff with a friend who has a backcountry super cub, which is a 200hp, constant speed equipped, super cub with extended wings and leading edge slats. Basically a $300k super cub with every mod known to man on it. When we went full throttle we both accelerated about the same off the line but I actually ended up pulling away, I took off slightly shorter than he did and then completely out climbed him. It was a good example of why a lighter weight aircraft is often the better performing one, and it definitely made me feel like I had spent my money on the right airplane, especially when I still out cruise him any day of the week while sipping 1/3 the fuel :D:D

To sum it up I am in love with the STi wing and landing gear. I have gone places with my plane that I didnt think you could land any plane at, let alone a Kitfox. It truely has turned into my dream plane.

Sorry for such a long write up, heres the fun part; pictures!

For those wondering the difference between the standard wing and the STi wing, here is a photo of a standard rib next to the STi rib. You can see the STi is thicker, longer and it does have a little extra camber to the underside of the airfoil.
http://www.teamkitfox.com/Forums/picture.php?albumid=487&pictureid=6063

Here's a while back during the initial fitting and rigging phase:
http://www.teamkitfox.com/Forums/picture.php?albumid=487&pictureid=6051

Setting the sweep:
http://www.teamkitfox.com/Forums/picture.php?albumid=487&pictureid=6050

Fairing the new struts:
http://www.teamkitfox.com/Forums/picture.php?albumid=487&pictureid=6060

Wings done with paint and fitting the wing tips:
http://www.teamkitfox.com/Forums/picture.php?albumid=487&pictureid=6065

AND... Wings on, ready for first test flight:
http://www.teamkitfox.com/Forums/picture.php?albumid=487&pictureid=6057

Comparison between the series 5 elevator and the 7:
http://www.teamkitfox.com/Forums/picture.php?albumid=487&pictureid=6067
http://www.teamkitfox.com/Forums/picture.php?albumid=487&pictureid=6066

Wings stil fold for anyone wondering:
http://www.teamkitfox.com/Forums/picture.php?albumid=487&pictureid=6058

New empty weight with the airmaster on still:
http://www.teamkitfox.com/Forums/picture.php?albumid=487&pictureid=6061

Prince P Tip prop:
http://www.teamkitfox.com/Forums/picture.php?albumid=487&pictureid=6068

And just some pics of out having fun:
http://www.teamkitfox.com/Forums/picture.php?albumid=487&pictureid=6054
http://www.teamkitfox.com/Forums/picture.php?albumid=487&pictureid=6053
http://www.teamkitfox.com/Forums/picture.php?albumid=487&pictureid=6052
http://www.teamkitfox.com/Forums/picture.php?albumid=487&pictureid=6069

Here's a video of a takeoff and landing at 5000ft with a 5-10mph wind: https://www.youtube.com/watch?v=NUeXpANxUvM

[rv9ralph]

Trent,
Great write-up. It looks like you are getting close to your dream plane.

It also looks like you did the final assembly at Kitfox Aircraft facility.

Looks good.

Ralph

[DesertFox4]

Excellent post Trent. Sounds like the STI delivers exactly as advertised.

[efwd]

Thats so cool Trent. Wonder when I will buy mine. To be honest though, seeing that pic of the sweep set up brought back some anxiety that I was experiencing back at that stage. Not sure Im ready to do that again just yet.

[David47]

Great description of what you're up to Trent. Looks like you have an excellent performer there. Well thought out and well done.

[av8rps]

Fantastic info Trent! I am very impressed.

And as well as that wing works to improve STOL performance, what I'm reading and seeing of your results, that STI wing looks like it would make one heck of a Kitfox float plane. And while the original Kitfox wing works well for that, the STI results you posted indicate it would provide a significant improvement when on floats. The added lift would help a lot to offset the added weight of the floats, which is like carrying a third person in your Kitfox for those of you that aren't familiar with amphib floats (exchange weight typically is 200 -250 lbs).

Your highly modified Model 5 is becoming one of the poster childs representing the Kitfox brand. And it certainly does a great job. I can see why it is your dream plane :)

[PNWJARED]

Trent,

This is awesome! This is my favorite thread. I love seeing the purpose driven experimentation and the data behind each change. Look foreward to reading your updates.

I am currently a tri gear looking at converting to tail wheel this winter. I changed the panel and installed a new motor last winter. It's a fun ride learning this aircraft.

Keep it up!

Jared,

[trentp]

Fantastic info Trent! I am very impressed.

And as well as that wing works to improve STOL performance, what I'm reading and seeing of your results, that STI wing looks like it would make one heck of a Kitfox float plane. And while the original Kitfox wing works well for that, the STI results you posted indicate it would provide a significant improvement when on floats. The added lift would help a lot to offset the added weight of the floats, which is like carrying a third person in your Kitfox for those of you that aren't familiar with amphib floats (exchange weight typically is 200 -250 lbs).

Your highly modified Model 5 is becoming one of the poster childs representing the Kitfox brand. And it certainly does a great job. I can see why it is your dream plane :)

The STi would be perfect on a float plane, tons of lift and it gets off so much faster which I would imagine would be beneficial on a float plane.

[Esser]

Nice write up Trent. Every time I see your posts I have a feeling in my gut that my traditional wing's days are numbered...I'll fly it for a few years before I do anything drastic...

[dholly]

Very good Trent. Glad to see some in depth commentary on this wing, sure reads well. Are the flaperons interchangeable between wings or longer flaperon push/pull control tubes necessary?

[trentp]

Thanks Doug!

The flaperons are interchangeable I believe although we did new ones. It does take different length control tubes going to the flaperons though.

[herman pahls]

Trent
Do you have an idea how much heavier the STI wings and new elevator are over stock?
Good to see the STI wings allow the wings to fold.
Any idea what the new width is?
Will the STI wings fit a model 4?
Thanks for sharing
Herman

[trentp]

Trent
Do you have an idea how much heavier the STI wings and new elevator are over stock?
Good to see the STI wings allow the wings to fold.
Any idea what the new width is?
Will the STI wings fit a model 4?
Thanks for sharing
Herman

The new wing added 38lbs to my plane.
I didn't happen to measure the new width :( I would think it would be 6-8in wider at the tail end when folded.
In theory the STI wing will fit the model 4 I would think but the question is how moving the flaperon attach points will work. It isn't something anyone has tried yet but I would think it should be possible.

[hamer]

So glad I found this thread. Been following you on IG and YouTube for a while now and was looking for more detail. Definitely taking notes over here, I’m hoping to build a similar setup someday, soon hopefully!

[PNWJARED]

Trent,

was just curious how you are liking the two blade. I saw some feedback, think you have been flying it a while. Wanted to hear if you had anything further to add.

Jared,

[Av8r3400]

I have a similar Prince prop to trents. Mine is a 78x48" and his is an 80x42". We both have fantastic low end pull from the props with some trade off in top speed loss.

My Mangy Fox will max out, wide open throttle, at about 120 mph. My old IV-1050 with the 68" 3-blade warp taper and 80 hp would do an honest 125 mph cruise all day long. But I can sustain 2000 fpm climb on my 105 hp zipper.