Decision time

[herman pahls]

I need this forums help with engine choice for my Model 2 Kitfox (520#'s empty , 950#'s gross , 15 gallon fuel and 100 MPH never exceed).
I flew this evening in perfect calm and really enjoyed my 80 HP Jabiru (production # 267).
It is every thing I want in an engine except I want better high altitude (6000-9000 feet) climb performance.
I have not tried the HacMan yet.
I know the tail feathers and CG can be modified to make a Rotax 912 viable but not sure I want to give up the useful load and alter the airframe.
I am convinced that the Rotax 670 will give the performance I want but the 300 hours TBO bothers me. Do I want to carry 2 cycle mix oil?
I flew this Kitfox for 12 great years with a Rotax 532.
I hear the newer 85 HP Jabiru has significantly better climb and cruise over the 80 HP.
The HKS turbo may be the best 4 stroke power / weight performance.
The 670 would be the least expensive and probably give the best climb.
Thanks Herman Oregon 541 404 6464

[av8rps]

I need this forums help with engine choice for my Model 2 Kitfox (520#'s empty , 950#'s gross , 15 gallon fuel and 100 MPH never exceed).
I flew this evening in perfect calm and really enjoyed my 80 HP Jabiru (production # 267).
It is every thing I want in an engine except I want better high altitude (6000-9000 feet) climb performance.
I have not tried the HacMan yet.
I know the tail feathers and CG can be modified to make a Rotax 912 viable but not sure I want to give up the useful load and alter the airframe.
I am convinced that the Rotax 670 will give the performance I want but the 300 hours TBO bothers me. Do I want to carry 2 cycle mix oil?
I flew this Kitfox for 12 great years with a Rotax 532.
I hear the newer 85 HP Jabiru has significantly better climb and cruise over the 80 HP.
The HKS turbo may be the best 4 stroke power / weight performance.
The 670 would be the least expensive and probably give the best climb.
Thanks Herman Oregon 541 404 6464

I'd put a 912 in it. If you put a 100 hp 912 in it, you'd have the performance you'd want I'm certain. And if you don't want to spend that much, pick up a used 912ul and put high compression pistons in it. The Jabirus are nice engines, but they need longer props for a STOL aircraft to perform well. The 912 excels in that area because of the slow turning, ultra efficient prop they run, using every ounce of horsepower to it's max. And fwiw, I'm quite certain the first Kitfox powered by a 912 was a Model 2, so that shouldn't be an issue.

[SkySteve]

" And fwiw, I'm quite certain the first Kitfox powered by a 912 was a Model 2, so that shouldn't be an issue."

I wouldn't be so certain about that. My model I has a 912A. Serial number 42.

[herman pahls]

Steve
Do you mind telling me again the mods required to get the 912 to balance and fly well in your model 1. Model 4 tailfeathers?
I assume your gross weight is between 850-950 #'s.
What is you empty weight and how does it fly.
Would you do this again or hold out for a longer model 4 fuslage next time?
thanks Herman

[SkySteve]

Herman,
My model I is a unique ship. One of the reasons I bought it was because it is the first real factory demo/show plane. Here is the history on my Model I:
http://teamkitfox.com/Forums/showthread.php?t=114]

My ship has an adjustable stack of lead in the tail to offset the weight of the 912A 80 HP. Empty weight is 660#; gross weight 1050#; VNE 100 mph IAS; she flys great and has taken me everywhere I have asked her to go. However, at this year's factory fly out to the Idaho backcountry there did seem to be a lot of radio chatter asking if the "ONE" was keeping up. My hangar partner has a model IV speedster. Much of our flying together is formation flying. In order to accommodate me he has done everything possible to slow his plane. We often joke that I have the fastest model I ever built and he has the slowest model IV Speedster ever built.

I love this ship and have spent way more money on mods and upgrades than I could ever possibly hope to recover if I sold it. It'ts been a great plane. Would I buy it again with what I know now? Probably not. If I were buying a Kitfox today, without question I would choose the 7 Light Sport with the 912S.