-we have only 3+2 prototypesHow much is the gear unit?
A single prop swirls the air. Any swirl is a power loss. A correctly designed contra prop spits out unswirled air. The rear prop unswirls the air from the front prop.Contra-rotating propellers obviously work or they wouldn't be used but I've never understood how immediately reversing a mass of air - the second prop hitting an accelerated air mass going 180 degrees from the direction of the second prop, makes any sense. Common sense (mine anyway) would say there would be a huge loss of energy in the rear prop dealing with the air mass developed by the front prop. Can anyone explain to a simple mind like mine why there wouldn't be bucket loads of drag developed in this configuration? Seeing contra-rotating props always leaves me wondering in my head how they work.
Checking the loop feature of you tube, when copy and pasted.I think I understand how it works. If right hand shaft is connected to motor and you put equal loading on output shaft and hub (propellers) then the left hand output shaft will turn the opposite direction as motor and the hub will turn in same direction but with both outputs rotating at half the input speed.
So for motor you get reduction box and extra thrust from 2 propellers and the propellers cancel out the gyroscopic precession.Link to files .https://grabcad.com/david.menashe-1
Edited I had it the wrong way round.
=iff both propellers have the same drag momentum,but with both outputs rotating at half the input speed.
A second advantage for the contra-rotating props is influx of fresh air caused by first prop slipstream contraction, but that is happening at low speeds or static condition; that's why some helicopters have a coaxial rotor. At higher speeds practically all air goes trough both propellers and as swirl is low anyway, there is not too much point for using contra-props. The single reason why high powered aircraft uses it, is because it enables much more power to be absorbed by a lower diameter propeller.A single prop swirls the air. Any swirl is a power loss. A correctly designed contra prop spits out unswirled air. The rear prop unswirls the air from the front prop.
>30 % moore thrust...(at equal diameter !)Your "experience "with contra rotating propellers and "straitening vanes" is what exactly?
=is it possible to made quastion more understand-able for me ?was dissing"dusan" for
claims of "experience" of "straitening vanes" vs contra rotating propellers.