Friday, May 28, 2010

Belite Pilot Operating Handbook

Pilot’s Operating Handbook - Belite 254 / Taildragger / Trike

This is not an FAA approved document.

1. Safe operation.

The pilot is responsible for verifying that the Belite is in a safe condition for flight. This responsibility is only that of the pilot, not of any other individual or company.

2. Limitations.

2.1 The Belite’s maximum gross weight is 550 pounds. Do not exceed this weight under any circumstance.
2.2 Under no circumstances exceed 80mph CAS. Do not exceed 80mph under any circumstance.
2.3 Do not use flaps unless speed is 62mph or less.
2.4 Do not taxi in more than 12 knots of wind.
2.5 Demonstrated crosswind component is 6 knots.
2.6 Never takeoff or land with a tailwind.
2.7 Always ensure that sufficient runway is available for takeoff and landing.
2.8 Pilot weight must not exceed 270 pounds.
2.9 All aerobatic maneuvers, including spins, are prohibited.
2.10 Do not exceed 2 Gs of wing loading (positive) or 0 Gs of wing loading (negative). (The carbon fiber wing has been static tested to approximately 3.8Gs positive and -2Gs negative, but this has never been demonstrated in flight.)
2.11 In order to maintain FAR 103 legal flight, ensure that empty weight does not exceed 254 pounds (without parachute) or 278 pounds (with parachute). Also ensure that level flight does not exceed 62mph under full power. (Utilize a ground adjustable throttle stop as necessary, or change propeller pitch.) Compliance is the responsibility of the pilot.
2.12 In order to maintain FAR 103 legal flight, stall speed must be 28mph or less under specified conditions. The wing design used in the Belite design is very heavily undercambered and is an excellent choice for slow stalls and slow flight. It must be possible to demonstrate a stall at 28mph when Belite weight is 254 pounds or less, pilot weight is 170 pounds, and fuel weight is 30 pounds. Compliance is the responsibility of the pilot.
2.13 In order to maintain FAR 103 legal flight, usable gasoline capacity must not exceed 5 gallons (30 pounds). Compliance is the responsibility of the pilot.
2.14 In order to maintain FAR 103 legal flight, cruise speed must be limited to 62mph or less. This may be achieved by engine selection, propeller selection, or by throttle stop. Compliance is the responsibility of the pilot.

3. Demonstrated takeoff performance.

The Belite has demonstrated a ground roll of 330 feet in medium grass and no wind, with a density altitude of 2600 feet. This was achieved with approximately 37 horsepower. Additional horsepower will substantially shorten takeoff roll. Conversely, reduced horsepower will substantially lengthen takeoff roll. At sea level, we estimate that a takeoff roll of 200 feet will be required with 37 horsepower (dry pavement, no grass, no headwind, standard conditions). Takeoff rolls of less than 100 feet have been observed under conditions of increased power and/or headwinds.

Wednesday, May 26, 2010

An independent comment on our plane & instruments

From Terry Alley:

I went to BeLite's shop last friday to visit with James Wiebe about changing the engine in my Kit Fox Lite to the Hirth F23 like the one he has in his new Superlite. While discussing the performance of his plane, James had a slip of the tongue and said "you ought to fly that and see what it feels like", I thought he would never ask.

After sliding into the cockpit I took a little time to familiarize myself with his new LED Panel. At first I thought it would be a little confusing trying to read all the lights but once I became familiar with their location, they were quite easy to read and seemed very accurate. I especially liked the Inclinometer and the Turn Rate indicator. Those two may have to find a way into my panel. The altimeter is zero'd before taking off and is only a AGL instrument, but what else would you want in a ultralight. I made several turns into and away from the sun and the LED's stayed visible reguardless of direction and lighting.

Now for my comparison between the original Kit Fox Lite which I have the new BeLite Superlite.

Cosmetically they look the same with the exception of mine having a full covered fuse. The interior, again no changes, other than the panel already mentioned. The only noticable difference in feel was the rudder. Belite has improved their design to use push/pull cables to the rudder. While they make the rudder feel a little stiff, the contol was very positive. Everything else felt the same excpet the power.

My Lite has a 37 hp 1/2 VW which I really love except for takeoff performance. On a hot day it will make you pucker up if you have to climb over some trees on takeoff. But the cruise is a nice 65 once you get there. The Belite had the new Hirth F23 opposed twin 50 hp. When I lined up on the runway and added power before I could look down to see what the RPM was, I was airborne. Not only airborn but I continued to climb at 50 mph and at a pretty steep angle of attack. Needless to say I was impressed.

After making some steep turns and doing a couple of stalls I concluded this new bird has the same great flying characteristics as the original Kit Fox Lite (when I say original that is what I mean as mine is serial #001). I decided to test the new spring shocks that James had just added to the gear that day. This a great replacement for the bungees (which I have had one failure on). I came in across the fence at 50 and let the speed bleed off until a did a nice wheel landing at about 35 to 40 mph. At that point, I added power without letting the tail come down and almost instantly I was off the ground again. The next approach I added one notch flaps and crossed the fence a little less than 50 but holding a little more rpm. The speed bled off and I held it off until the airspeed dropped to just below 35 and it settled on all three wheels for a short rollout. The new spring shocks worked great in softening the touchdown with no bounce at all. I thought it was my landing skill but James assured me it was the new gear.

Conclusion: The Superlite is a great little airplane especially with the F-23 in the nose. If you are looking for a safe reliable plane that is a blast to fly, give James a call. And for all the Kit Fox Lite flyers out there, be thankful James picked this plane up and put it back in production. Any part you might need for your plane just became available plus many upgrades.

Terry Alley
Kit Fox Lite

Tuesday, May 25, 2010

Analysis of the Belite airfoil

Hi everyone,

A Belite follower (Theodore Fails) wanted to analyze our airfoil, so I sent him a CAD drawing of a rib cross section. Ted did a very able job of tracking down the likely origin of our airfoil. It's fascinating stuff. I thought of summarizing it, but Ted's letter to me is well written and is a good aeronautical detective story. With Ted's permission, here is his analysis. Enjoy!!

-- James Wiebe


Here is progress report on analysis of the Belite airfoil:

1) It is clearly a Riblett airfoil, but it is outside of the matrix of airfoils covered in the book "GA Airfoils." From personal discussion and correspondence with Mr. Riblett, I was able to extrapolate from his data and closely duplicate the Belite airfoil. (Mr. Riblett, at age 80 was delightfully cogent on the subject, though he could not recall if he had in fact designed an airfoil for Kitfox. He did have some suggestions for Ultralight wings which I will cover below.)

2) The Belite airfoil has a built in 2.37 degree angle of incidence, giving some nominal lift at zero angle of attack.

3) The actual designation of the foil, using Riblett's method of nomenclature is GA30-8M12. "GA" means it is a Riblett foil using his method of direct addition of form ordinates to camber ordinates. "30" means that maximum foil thickness occurs at 30% of chord. "-8M" means that the camber is a slight modification from Riblett's camber level -8. Perhaps "-8.16" would be a better description, since the Belite foil is about 16% more cambered than Riblett's -8 camber. "12" means that the maximum foil thickness is 12% of chord. Maybe GA30-(8.16)12, whatever.

4) In my talks and correspondence with Mr. Riblett he suggested that for Ultralight foils, that a good choice would be a GA25-815 foil. It would be thicker overall and thicker at the leading edge, allowing a larger spar. Whether it would be worth the cost of the change or not is an open question, or even if it would improve performance at all.

5) See attached jpeg showing the Belite foil overlaid on the GA30-812 foil. The GA30-812 is closest foil that falls within the span of Riblett's data. As per 3) above, the Belite foil is more cambered than any of Riblett's standard foils. (His book covers four camber levels, -2, -3, -4, and -6. He sent me some unpublished data adding camber level -8.)

6) The small amount of washout in the Belite wing is also in accordance with Riblett design parameters. This allows a lower stall with good control and pays a lower price in drag a cruise speeds. Good stuff.

Sorry it took so long, but after I got a copy of the Riblett book and your foil did not match any of his, I naturally assumed it was something entirely different, so off I went on a wild goose chase. After learning a LOT about a LOT of other foils, I decided to just give Harry a call. The Belite just Looked like a Riblett foil.

The next step for me is to do some computational fluids testing of some foils that I am interested in. I like your airfoil ... very much. I will include it in my test matrix, and let you know the results if you have any interest.

Lastly, I am curious about the bracket drawings that you sent. Being a manufacturing engineer in my day job, I wonder how you actually make these things. Hog-out? Weldment? Sheet metal fabrication? What sort of quantities do you buy in? FYI, I have a Haas VF-3 and I know how to use it! If I get a moment I may examine these items for structural optimization, you may be able to save some mass or cost or both.

Anyway, sorry for the delay, and again, let me tell you how much I admire what you are doing in the Ultralight market. Keep up the great work.