this is a polar cord file of three different airfoils , SD6062 7.5%,RG15 7% and FX791217operating with a 7.5 in cord at 300mphthe FX is the clear winner
Don't forget the following in developing your ac:
Elliptical platform (or ideal taper)
High aspect ratio Properly constructed wing-tip devices. It shouldn't look like a boeing, and will require quite some testing.
wing-body blending.
Area rule your fuselage.
Remember that all these apply to your control surfaces too.
size your control surfaces for min required control power
use weight and balance to generate the required 'g' in the shallower part of the turn. But don't do any of the above if it will add an unacceptable amount of weight. What is unacceptable? The only real way to find out is wind-tunnel testing...
Have you thought of coupling the DS airframe with some variation on the current UAV autopilots so that it flies perfect elipses on the slope....something like a small 6 waypoint track. Would probably require DGPS so it would be accurate enough to not drift into the hill accidentally.
Ive added a slightly modified section that traded 4-5 drag counts at High CL for a loss of 13-14 drag counts at low CL's.
If you look at the difference between the RG-15 and the new AQ, for the same alpha that the RG gets a CL of 0.800, the new AQ section produces a CL of 0.901, so then your able to scale back your wing area by 12-13%. This will offset the drag difference at low CL's, plus the lower CM will enable you to downsize the tailplane as well if its on the same arm length...this again reduces drag, plus the tailplane trim drag is likely to be smaller for the same reasons.
Done correctly, you should go through this loop a few times to figure out the speed increase, which would then allow you to downsize the wing and tailplane even further...taken to it's conclusion you should be looking speed increases that approach double the 15% I mentioned earlier.
awsome . the next question is how ever do the gains in Cd performance in the corner over come the poor Cd performance at low Cl ? the rg-15 clearly has a huge advantage @ low Cl.thanks foir the 'foil , very interesting you can see the same kind of design phillosophy but the AQ is much more refined , i also like the lower Cm . what program are you using?hopefully in a month or so i should have a bird in the air i think i will try the AQ first . thanks for the help.
This is a hacked around FX section. The original wasn't a very good section and really required to be cleaned up. The original RG-15 at the design CL of 0.80 had 88 drag counts, The FX was at about 70 drag counts in the same condition and I got the new AQ section down to 48 drag counts. With luck and the right trim, that should up your speeds by at least 15% if not more.
this might be a bit better, comparison against the RG-15 section found in the UICC database scaled to 7%, couldn't find the FX section you mentioned, would be nice if you posted it here so I could play with it. Have attached the dat file for the AQ08 07-300 section
Comments
Elliptical platform (or ideal taper)
High aspect ratio
Properly constructed wing-tip devices. It shouldn't look like a boeing, and will require quite some testing.
wing-body blending.
Area rule your fuselage.
Remember that all these apply to your control surfaces too.
size your control surfaces for min required control power
use weight and balance to generate the required 'g' in the shallower part of the turn.
But don't do any of the above if it will add an unacceptable amount of weight. What is unacceptable? The only real way to find out is wind-tunnel testing...
If you look at the difference between the RG-15 and the new AQ, for the same alpha that the RG gets a CL of 0.800, the new AQ section produces a CL of 0.901, so then your able to scale back your wing area by 12-13%. This will offset the drag difference at low CL's, plus the lower CM will enable you to downsize the tailplane as well if its on the same arm length...this again reduces drag, plus the tailplane trim drag is likely to be smaller for the same reasons.
Done correctly, you should go through this loop a few times to figure out the speed increase, which would then allow you to downsize the wing and tailplane even further...taken to it's conclusion you should be looking speed increases that approach double the 15% I mentioned earlier.
Perf Graph
AQ08H 1160-243 @ CL 0.80
AQ08H 1160-243.dat
Perf Graph
RG-15 @ CL 0.80
FX91217 @ CL 0.80
AQ08H 1189-344 @ CL 0.80
AQ08H 1189-344.datcool stuff , although i cant read the numbers .
AQ08 07-300.dat-
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