DJI S800 prop pitch

[FerdinandK]

@DennyR
Here in this forum, it is a bit difficult to argument, so yes you are the expert, so most likely you will be right. The only thing I can add is, that SR are different (very) from MR, a "blade-stall" depends on the angle of attack and the profile used, and the Reynolds number, and that I must have done something totally wrong in here:

65min flight:
https://vimeo.com/38908434
21:30 min flight with a Zenmuse and Retracts (2,5kg payload) at 30km/h forward speed
https://vimeo.com/61296767
All done with 14x8 Props.
I am also sure that I am able to fly at high altitude (3000m+) but I have to video for this yet.

The stability of an SR also increases with the "energy" stored in the main rotor, which is e.g. a major difference to MR.

But as I said above you are the expert you are most likely right. Sorry for my comments.

best regards

Ferdinand

 

[gtranquilla]

Incidentally Howard Hughes aeronautical engineers developed in the 40's or 50's a plan with paired counter-rotating props that was deemed to be more efficient than using for separately located motors/props.... but then he crashed the plane and moved on to other things. Apparently there is an optimum pitch for each pair of counter-rotating props that is advantageous over same pitch pairs.......

I guess what we really need from the MR perspective is a variable pitch prop and control system as well as reducing the number of props/motor down to three so that there is also some stability benefit from prop momentum, i.e., potential energy....... or keep it simple and stick with SRs!

@DennyR
Here in this forum, it is a bit difficult to argument, so yes you are the expert, so most likely you will be right. The only thing I can add is, that SR are different (very) from MR, a "blade-stall" depends on the angle of attack and the profile used, and the Reynolds number, and that I must have done something totally wrong in here:

65min flight:
https://vimeo.com/38908434
21:30 min flight with a Zenmuse and Retracts (2,5kg payload) at 30km/h forward speed
https://vimeo.com/61296767
All done with 14x8 Props.
I am also sure that I am able to fly at high altitude (3000m+) but I have to video for this yet.

The stability of an SR also increases with the "energy" stored in the main rotor, which is e.g. a major difference to MR.

But as I said above you are the expert you are most likely right. Sorry for my comments.

best regards

Ferdinand