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Re: Mono wheel vs. Tri-Gear debate

Subject: Re: Mono wheel vs. Tri-Gear debate
From: Graham Singleton <grasingleton@avnet.co.uk>
Date: Fri, 10 May 2002 01:21:39
>One of my dreams is to fly to fairly high altitude Idaho grass forest 
>strips to do some camping and fishing.  I believe the Tri Gear is a better 
>choice because it can get off the ground easier because you don't have the 
>drag of the flaps being down like you do on the Mono wheel.

My humble opinion,
I don't know of a like for like comparison of the performance differences , 
except for the UK Orkney Island Mono that was converted. Top speed was not 
very different, but if it's take off that's important, the Mono is better, 
everything else being equal. ie weight , power and prop performance.

Early on in the roll wheel drag is the problem, mono will be less. Around 
20 knots mono will be even better, the ground effect of the wings and flaps 
will produce a lot of lift and not too much drag reducing rolling 
resistance even more. (there's no induced drag in ground effect) The drag 
of the flaps will not be a problem until up to flying speed, you are off 
the ground so as soon as positive climb is established you can unlock the 
gear, raise the flaps a little then slowly ease them up. This is easy to do 
because the flap will stay more or less where it is placed, there is almost 
no lever load at any flap position because the flap is pivoted in line with 
its center of pressure.

The big advantage of the tri is landing. If a short landing is needed the 
tri wins every time, (apart from ploughed fields etc.) because firm braking 
can be used as soon as the wheels are on the ground. On wet grass using 
brake on the mono will have you off the runway in no time. (bin there) 
Steering is lost if the main wheel locks up, which it will if you panic or 
forget what your right hand is doing. On dry grass or hard you risk dinging 
the prop

If I was a bit younger I would be very tempted to try a bicycle 
undercarriage (like the B47, Harrier AV8 B52.) Best of both worlds, easy 
retraction so less drag. It was disappointing to realise that the mono was 
not as low drag as we all hoped, maybe the outriggers were the reason, or 
the big hole around the wheel. I would love to have a brainstorm with a few 
of the fast guys like Kim Prout, Peter Kember and the rest with Don Dykins 
as chairman. That would be a good party.

The other thing I would want to do would be to increase the wing span a few 
feet but keeping the same wing loading . Glasair did that with the Glasair 
1 to improve the climb and low speed handling. They also got a bonus, it 
went faster.

Graham



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