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

[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.