http://www.youtube.com/watch?v=H_xaXVyw9jE&feature=player_embedded#at=355
This is much of a 'Tamasha' plane, without any aerodynamics. Why not put a 'Shakira' instead of a mock plane body!... It would not fare well on scale factor as dreaded 'Reynolds Numbers' would make such design practically impossible. Good on small foamies only.
Quote from: ujjwaana on May 19, 2011, 09:38:02 PM
Why not put a 'Shakira' instead of a mock plane body!...
ha ha ha! funny video and hilarious comment :giggle:
Whats so funny about it?? This guy has got skills most of us can only dream of... and he's got the right equipment for it. :thumbsup:
Hmm..wonder how many here could do this :headscratch:
Well I for sure, cannot do it, dont want to. I am only interested in planes :thumbsup:
how come it can go backwards?
It has a Variable Pitch Prop (VPP) setup. Hence it can go backwards....
Read up on "Variable Pitch Propellers" (VPP). It is the same reason why RC helis can hover inverted.
The concept is there in almost all real life aeroplane with a prop. whether reciprocating engine or a turpoprop engine, the concept in these aeroplanes is, the RPM is nearly constant , what changes the thrust is the variable pitch, as you increase the pitch the torque increases the RPM tends to drop and the fuel flow to the engine increases and the RPM is once again maintained constant.
now on landing, these propellers are withdrawn for reverse thrust, in fact some of these aeroplanes can even taxy rearwards, (Of course with a severe restriction on speed). These foamie RC aeroplanes are following the same principle, RPM is near constant and the pitch is varied for forward and rear thrust. the weight is so less that it near instantly travels rearwards. when it does the control inputs are reversed like you control a tail-slide, tailsliding aerodynamics is very complicated and control is difficult because a rear traveling aeroplane is inherently unstable
ufff (So much after two day sabbatical)