Head in the clouds
Well-Known Member
Structures I can do but aerodynamics is not my strong point so I would appreciate any help HBAers can offer.
The project is what is represented by my avatar - almost - there are some fundamental differences which will reveal themselves as the design process firms up. Essentially the intention is to keep it as close as possible to what is portrayed but the final version will be a roadable 'flying car' or 'flying 3 wheeled motorcycle' to be more precise.
I have the wing folding sorted, it folds into a quite attractive package (well it won't get the nickname 'fugly' anyway) 7ft 6in wide and 6ft high.
As with all aircraft there are compromises of course and adding the driveable aspect threatens to increase the number of them. I need to determine which of them could be most detrimental. The primary focus at this stage is to evaluate the result of the form changes I need to make in the wing shape, to permit the best arrangement when folded.
It is intended to build the prototype incorporating the wing folding system only, but with provision to add the road transmission and steering when the flight characteristics have been proven.
I'll post each subject into different threads as some of them may prove to be a useful resource for others in the future.
1. Aspect Ratio - (NOTE - for this example the wing is parallel and unswept)
From an earlier thread I understand that the stall AoA is affected by the Aspect Ratio of the wing. It would be a help to know something of the real value of that stall angle change with change of AR.
So - for those of you with aerodynamics training, foil software and/or too much time on your hands -
a. Are tip effects the only cause of stall AoA change with change of AR?
b. The discussion in that previous thread led me to understand that the change of stall AoA is non-linear with change of AR i.e. as AR becomes very low the stall AoA increases even more rapidly. Is that correct?
c. Can someone provide a graph or table to show the rate of those changes for the following example - a simple wing with two ends (tips), no fuselage involved in the example, 4ft chord with ARs of 12 down to 1? Any common section will do - say Clark Y? Assume no winglets/fences etc.
Thanks, Alan
The project is what is represented by my avatar - almost - there are some fundamental differences which will reveal themselves as the design process firms up. Essentially the intention is to keep it as close as possible to what is portrayed but the final version will be a roadable 'flying car' or 'flying 3 wheeled motorcycle' to be more precise.
I have the wing folding sorted, it folds into a quite attractive package (well it won't get the nickname 'fugly' anyway) 7ft 6in wide and 6ft high.
As with all aircraft there are compromises of course and adding the driveable aspect threatens to increase the number of them. I need to determine which of them could be most detrimental. The primary focus at this stage is to evaluate the result of the form changes I need to make in the wing shape, to permit the best arrangement when folded.
It is intended to build the prototype incorporating the wing folding system only, but with provision to add the road transmission and steering when the flight characteristics have been proven.
I'll post each subject into different threads as some of them may prove to be a useful resource for others in the future.
1. Aspect Ratio - (NOTE - for this example the wing is parallel and unswept)
From an earlier thread I understand that the stall AoA is affected by the Aspect Ratio of the wing. It would be a help to know something of the real value of that stall angle change with change of AR.
So - for those of you with aerodynamics training, foil software and/or too much time on your hands -
a. Are tip effects the only cause of stall AoA change with change of AR?
b. The discussion in that previous thread led me to understand that the change of stall AoA is non-linear with change of AR i.e. as AR becomes very low the stall AoA increases even more rapidly. Is that correct?
c. Can someone provide a graph or table to show the rate of those changes for the following example - a simple wing with two ends (tips), no fuselage involved in the example, 4ft chord with ARs of 12 down to 1? Any common section will do - say Clark Y? Assume no winglets/fences etc.
Thanks, Alan
