Kitfox vs highlander stol performance

[Dead Roman]

So, Im still shopping for a kit to buy. I have been on the kitfox bandwagon for sometime now and have just been trying to find a used project fox at the right price. I know the kitfox supersport has a 1500lb gross weight which definately appeals to me. The highlander on the other hand only has a 1300lb gross, but the STOL performance is out of this world. I plan to fly my plane to my parents hometown and the landing strip there is a 700ft grass strip for rc planes(abt 40ft wide). From videos I have seen the highlander can land and takeoff from that with room to spare. How would the supersport fare on a strip like that? While I like the highlander for STOL performance I like the kitfox for its sleek looks and high gross. Although the fact that the kitfox kit is roughly 10k cheaper is also a big factor.Either airframe I go with will be powered by a corvair with 120-130HP available for takeoff. A model 4 is also in running in spite of the low gross weight, having seen kits going in the 8k range on barnstormers its very tempting



I apologize if bringing the highlander up on the kitfox site is sacrelige lol

[HighWing]

Roman,

I have a friend that had a 1000 ft. strip at his place until he measured it. It was 700 ft. He was in and out often, mostly daily, in his 604 lb. Model IV with 80 hp. He had the same wing the 7 has. Taking off I doubt would be the problem. HP won't help land short, unless you are comfortble flying final behind the power curve. Heavier usually means faster on final. Also consider the elevation. My friend's place was at about 130 ft.

The 7 is a great airplane and has some features I will be without in my present project, but considering the mission, as you are doing, is very prudent. Have you considered the IV? That's what's working for me.

Lowell

[Dead Roman]

I am actually considering the IV as well. The price I see unfinished kits going for seems almost too good to be true. Im also considering scratch building my own aircraft. If I was gonna buy a kit right now I would most likely go for the SS/7. The 1200lb gross weight on the IV is the one major thing holding me back on it. I plan to use a corvair powerplant and the added gross weight of the SS sure would be nice.

[Dead Roman]

Im comparing 3 planes and I dont see how it is apples to oranges. All three planes are kit-builts of the same construction, use the same powerplants, and are spec'd at nearly identical empty weights. This is CLEARLY and apples to apples comparison.

[Av8r3400]

No, you are not comparing apples to apples.

The STOL performance of the Highlander with the same engine will be far superior to the Kitfox due to the wing design. The Highlander uses Dean Wilson's Avid (and I-III Kitfox) undercambered airfoil. It has much higher lift profile at low speed, compared to the Model IV and later Kitfox wing.

Not only is weight important, but wing design is, too.

One of these 900# fat Supersports is not going to come anywhere near as good as a 550# Model IV, or better yet a Highlander, in STOL performance.

At speed, the Kitfox (even a heavy one) will kick butt, though. The Kitfox is a good plane for STOL performance, but the Avids and Highlanders are better, due to their wing design. Sorry.

[Slyfox]

C5engineer that was great, thanks for posting.

[Dead Roman]

C5 i apologise if i came off as over aggrssive.

Thank you av8r i was unaware of the difference in airfoils.




Could a model iv be made to perform similarly or would it be better to just go with the highlander?

[Av8r3400]

The only chance to make a model IV STOL with a Highlander or Avid is to make it SUPER-SUPER light. That means a light weight engine like a Rotax 582 is mandatory.

My IV is 630# empty. It falls short (by a lot) to the STOL performance of a Highlander.

[HighWing]

My take on this is to go with the SS if the Corvair engine is etched in stone. Comparing a 600 lb. Model IV or Highlander with a ULS to a 750 lb. or more IV or Highlander is definitely apples and oranges. There is just too much experience out there to suggest that keeping any auto conversion close to the low 600 lb empty weights is simply not possible. I know this last statement is not popular position with a lot of folks, but all the argument so far that it can be done comes from hopefulls with calculators. As far as landing at your parent's place, that would depend on your piloting skills. I'd just go with the plan and have your folks pick you up at the local airport. Then again if lots of off airport work is in your plans, I would seriously reconsider the Corvair - Sorry.

[Newkid]

My dad used to fly our Model IV Speedster with a 912UL out of our 600ft strip with a house and trees at one end and a fence and hill at the other. It did fine, probably could have even done it with two people. This was in the summer and at 2,400 ft. Just build the plane as light as possible and it should be a performer, that Speedster only weighed 604lbs. You can make a Model IV come close to a Highlander, but it probably won't do quite as well, but in cruise a Kitfox will beat a Highlander. Just what I have noticed over the years.

[Slyfox]

Just remember one thing, you can have the best airplane, but it takes a good pilot to make that airplane perform.

[horsepower]

Im with you Slyfox, I would have to have a lot of hours and shortfield time before attempting to do what the guy in video does.I saw the dead stick takeoff that Joey is talking about, if I ever did that with my wife in there she would club me over the head.Plus not to sure I would want to pound on my airplane like that, although it did look like a kick in the butt.
Randy

[jonbakerok]

Pick a mission. You can't have it all. You said you want a cheap plane that can use a 500' field.

But you also want:
-- 1500 pound gross
-- Corvair power
-- Usable cross-country performance

If you really want the first, forget other three. Look for a used Kitfox 3 with a 582 rotax. I see them all the time on Barnstormers under $20K. Otherwise, pick the latest Kitfox you can afford and practice your short field technique. Any of them will technically land in 500' (for that matter, so will an RV!), but nothing over 1200 pounds with a decent cruise is really going to be SAFE on that short of a field unless you're a helluva pilot. When you can routinely land in 250 feet, then you're ready for a 500 ft runway.

[Dead Roman]

I reckon ill end up going with a mod IV or higher then. I dont wanna run a 2 stroke if i dont have to and the corvair is pretty much set in stone. I suppose useable cross country performance is more important than short field performance. I just want to be able to get in and out of grass strips easily. I suppose i could get the local runway extended to abt 1000ft. I reckon it just depends on which kit comes up on barnstormers. I sure would like to get an unfinished 5 or higher. Than you everyone for your insights.

[Av8r3400]

If the Corvair is set in stone, be prepared for lead in the tail to get it close on the CG envelope.

These motors, like the Subaru weigh 220+ pounds installed. That's a lot for the nose of a IV. One of my chapter mates has a Suby on a IV. Between the weight of the motor and the lead in the tail, it is now for all intents, a single seat plane...

[Dead Roman]

I should be able to get the corvair down to 200 flat without electric start(which is the plan). The rest of the aircraft will be built ultralight. Basic panel... No frills at all. But ideally an un started/un finished 5+ is what im looking for.

[Dead Roman]

1. The corvair has been flying for over 30 year in pietenpols and is currently flying in many different airframes. It has a proven track record and is proving to be a great aircraft engine. I would be willing to bet that the corvair engines rate of completion is close to any other powerplants. William wynne has developed the corvair into a fine aircraft engine. If you do the research on this powerplant as I have you would know this.

2. People have been hand propping aircraft for YEARS, many still do. Sure electric start is alot more convenient, but i can build without and add later if i dont like hand propping. It not like no-electric start is set in stone.

3. I just wanted to compare the stol performance of the 2 airframes. STOL isnt the only criteria.


If you want to discuss, MY thought process further feel free to PM me. But next time please consider what your are typing before you post. I dont

[Av8r3400]

It is obvious that you have some investment to the Corvair engine. I'm sure that this engine could be made into a viable aircraft engine. In the application you are looking for, why not go with a proven combination and build a Piet or one of the other "common" installations for your Corvair. Something designed for a 250# engine, not a 150# Rotax.

The Kitfox (and Highlander, Avid, SkyRaider, etc.) need a powerful and LIGHTWEIGHT engine to balance and perform they way they were intended. The Corvair engine just does not fit this application very well.

Can it work? Sure. There are Subarus, Lycomings, Continentals, Rotecs and other heavy engines flying in these planes. It this optimum? Light weight is the key to performance in these planes, so probably not.

Also, for the record, have you ever hand propped a 130 hp 6-cylinder engine? I would not suggest you do this with an engine like a C145 in a 170 or 172. Can it be done? Again, yes it can. Is it foolish? ---

Food for thought...

[av8rps]

Kitfox vs Highlander....hmmmmmmmm? I have time in both Highlanders and Kitfoxes, so let's see if I can help.

Lets start by comparing a Model IV Kitfox to the Highlander.

The Highlander uses a modified Avid Flyer airfoil which is world famous for its exceptional STOL characteristics. The airfoil makes gobs of lift at very low speeds, giving the Highlander (and the Avid) a very short takeoff at very slow speeds. But all that lift also creates gobs of drag. Fortunately that drag is useful in making incredibly steep descents at very slow speeds. So the Highlander lands as short as it takes off, just like the early Avid Flyers did.

But what a lot of people don't know is that todays Kitfox started with essentially the same airfoil. Consequently the Kitfox enjoys SUPER STOL capabilities as well. But people wanted better cross country capabilities. So Kitfox hired a famous airfoil engineer by the name of Riblett to further refine the airfoil design. That resulted in a wing that kept most all the SUPER STOL characteristics while reducing the overall drag profile, which provided a significantly improved cruise speed. The new wing worked so well that Kitfox made this new wing the standard on every Kitfox starting with the Model IV. This new wing represents the largest difference between the Kitfox and the Highlander.

All that said, the Highlander will still have a slight advantage in the bush. That old airfoil is pretty hard, if not impossible to beat in that environment. But if you want to still be able to do that STOL stuff, AND fly much faster and efficiently, the Kitfox has the distinct advantage. The Kitfox is also much more nimble to fly. Not that the Highlander is heavy on controls, but by comparison to the light super nimble characteristics of the Kitfox the Highlander feels much more "Cub like".

I believe in the extreme off airport operations the difference between the Highlander and the Kitfox will be more limited by the pilot than the airplane as both designs are exceptional. It's kind of funny how we don't see the extreme videos featuring Kitfoxes, but I'm convinced there's no reason they can't do it if they want to. But hey to each their own.

Fwiw, I just spoke with a gentleman last night flying a Model IV Kitfox with a 912uls and an IVO IFA prop. He operates regularly out of a 900 ft strip with powerlines at each end. And his field elevation is 3,000 ft. So that should tell you something. Oh yeah, he has large tires and minimal streamling on his plane and he admits that he has concerns about overspeeding his Fox, as he can easily redline it straight and level. I think his comments are a good represenatation of what a Kitfox can do. As i said earlier, it is probably more about the pilot.

New Kitfoxes? The new Kitfoxes are much more refined than the IV's are, and appear almost "cushy" by comparison. that also makes alot of people think that makes them pavement-type aircraft. But that couldn't be further from the truth. They are every bit as capable in the bush as most anything you could buy anywhere. So just like the IV's, they are still probably one of the most versatile and capable aircraft out there. I really like Highlanders and would love to own one one day. But I wouldn't sell my Kitfox to do so.

Speaking of STOL, check out this fun youtube clip of an early Avid Flyer demonstrating its SUPER STOL capabilities. Oh yeah, and when watching it remember that it takes a normal seaplane 2 to 3 times the lenghth of a land plane to take off...

The seminal design of our modern day Kitfoxes and Highlanders all started with the Avid Flyer...Imho they redefined the term STOL.

http://www.youtube.com/watch?v=qjDSatUSoCY