Kitfox Lite gets a Hirth engine — New engine on an old lite

Terry Alley’s Kitfox Lite … now has a Hirth F23 installed!

From Terry Alley, published on SkyStarKitfoxLite forum and republished here —


I just finished the installation of a Hirth F23 on my Lite. I bought Serial #001 [Kitfox Lite] from Earl Downs in Cushing, Ok a few years ago and began flying it with the old 2 SI.

A little over a year ago, I decided I wanted to try a 1/2 VW in the plane even though I was advised it would not have adequate climb performance. Well they were right. I loved it in the air with a cruise of about 62 to 65 mph indicated and a fuel burn of only 1 1/2 gal. per hour. What I hated was wondering if I was going to clear the trees ahead on a hot day. At best on a cool day I might get 200 to 250 FPM climb. So about a month ago I let James Wiebe of (www.beliteaircraft.com) talk me into flying his Superlite with the F23 engine installed. That is all it took.

I removed the VW and purchased a Hirth F23 from Belite Aircraft and had them make the motor mount for the Lite. Since they are building the Belite from the Kit Fox Lite tooling, the motor mount and engine went on like a plug and play accessory. My only real challenge was building the exhaust to keep the desired length of pipe and still hang it effectively under the engine.

Thursday evening, I finally completed everything and took the plane form my shop to Belite for final carb tuning. When all was satisfactory I decided to take it around the patch and see how it performed. I only had a gallon of fuel so it had to be short. WOW!!! This thing has never climbed like this even after a dive to build speed. After two touch n goes I landed and let James take it around to see if it felt like his new Superlite. He concluded that the feel is the same only his plane is much lighter.

Today, I had the chance to burn a tank of fuel through it and really test it out. Since I haven’t been flying for the last month the pasture I fly from was not mowed. Even with morning dew and a foot tall grass the plane leaped from the earth like never before. I climbed and before I reached the end of the 1700′ strip I was around 400′ in the air. Once at 1000′ I leveled off and at about 75% power my indicated was airspeed was close to 75. I am registared Expermential so the extra speed is OK. As I advance the throttle forward I watched the airspeed go to 80 and past. Since VNE is 80 I backed off at about 82 mph. My CHT held steady at 400 to 450 and EGT ran at 1050 to 1100 at cruise. (75% power) I flew south into the wind indicating about 75 mph and a GPS reading of 63 to 65. When I turn north, my ground speed jumped well over 80 and I was still at 75% or less on the power.

If any of you own a Lite and are considering a new engine, contact James Wiebe of Belite Aircraft. He can build the motor mount and set you up with a F23 which will make a whole new plane and do it without adding any more weight than the old 2 SI. The F23 with elect start weigh’s under 80 including starter and exhaust. Remove the Starter and save even more. James Superlite is strictly ultralight and he has to put in a mechanical throttle stop to keep the speeds legal. Obviously, I did not.

Terry Alley
Augusta, Ks

2 thoughts on “Kitfox Lite gets a Hirth engine — New engine on an old lite

  1. I recently acquired a kitfox lite with the original 2Si 460F-35. Have not yet flow but have considered upgrading due to our altitude at 4500asl. Am wondering what the estimated total investment might be to have the mount/Hirth power plant on my kitfox. Any other input and discussion would also be appreciated. Darrel McKay, Fruita, CO. 970.216.7706 cell

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