I found a site with specs for wheel friction:

http://personal.eunet.fi/pp/davinci/osa2.html

and for drag in general:

http://en.wikipedia.org/wiki/Drag_coefficient

It is important to have minimum friction at the wheel while taking off..because the most power is needed to get airborn.

I was using the thrustHP calculator and seems that taking of with 22 hp is a challenge with Max II...Cri Cri was able to do it with 18 hp like DA-11 and prototype of Quickie ( by Burt Rutan ).

Maybe I will istall also a nitrous injection device to get 35 hp for the take off and the speed dash ?

Here in english the friction coefficients: http://www.legslarry.beerdrinkers.co.uk/tech/JL.htm

See how little thrust the 22 hp delivers:

Cri Cri jet has 36 kg of thrust and flies well on one engine ( 100 mph ).

http://www.amtjets.com/gallery_real_plain.html

Drag will also be increased by little things like pitot tube that measures the speed:

http://fi.wikipedia.org/wiki/Pitot-putki

AR-5 story they talk about 0.0037 drag coefficient: http://ar-5.com/kitcarm93.html

According to this data and known dimensions i get drag force of 3,2 kg for the fuse of Max 3 at take off speed of 100 km/h.

Tailfeathers and wing has even less, but gear extented gives a sizeable increase compared to AR-5 gear. Gear drag is 14.2 kg at 100 km/h.

## 2009-02-21

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