comanche180
Member
I?m sure this has been asked..... but is the only difference between the -7A and -9A being the -7A is aerobatic and the engine you can install?
Another question can you put 500lbs of people and some bags in a 7 or 9?
My 9a came out empty at 1031, gross is 1750.
So answer is YES, depends on bag weight but may or may not have full fuel.
Van likes the -9 better.
Scott is right, the -9's ailerons do get stiff; however, the -9 has better balanced controls than the short wing RV's.
BTW, the 9/9A doesn't float any more than any of the other models will unless it is not on the proper speed for landing (and that can be said for all the models)
Scott is the expert but I will say this. The high-aspect wing on the -9 does not, in my free opinion, retain the energy that the wing on the -3 thru -8. What I could do in the -3,-4,-6,-7,-8 as far as loading the during the landing phase will not work with the -9 as the accelerated stall characteristics are different. Yes the -9 will land slower, but that will will bite if you load it up. Same with the other models but they seem to be a little bit more forgiving. Just my opinion and I?m not taking anything away from the -9 as I agree with many people that the -9 is the best kept secret in the Vans stable.
My point is that even though it can be a floater due to its efficiency, and even though it’s got a great low stall speed, it doesn’t carry the energy when loaded like the others (1g or whatever). Aeronautical engineers know this as common knowledge concerning the high aspect wings.
Something I've never seen addressed is crosswind handling. Does the longer wing and smaller aileron on the -9 make it less crosswind-capable? The -7 is one of the best crosswind airplanes I've ever flown.
Actually, the opposite is true.
It's not so much "loading it up" but rather L/D at higher angles of attack. And, all else being equal, higher aspect ratio wings will have *less* drag (specifically, lift-induced drag) at high AoA than will lower aspect ratio wings. But all else is not equal here; there is a different airfoil present on the 9 and it's almost certainly not optimized for high alpha manuvering given the stated mission of the design. Perhaps that factors in - but it's certainly not aspect ratio that would be causing the behavior you describe.
For all its other virtues, I think the -9/A is satisfactory in crosswinds, but not great. Then again, there's lots and lots of control authority in the flare in all three axes, and that helps.
Something I've never seen addressed is crosswind handling. Does the longer wing and smaller aileron on the -9 make it less crosswind-capable? The -7 is one of the best crosswind airplanes I've ever flown.
Something I've never seen addressed is crosswind handling. Does the longer wing and smaller aileron on the -9 make it less crosswind-capable? The -7 is one of the best crosswind airplanes I've ever flown.
Basically, yes, but not for the reason you stated, if I've got my facts straight. One problem is that, in general, the slower the landing speed, the less crosswind capability the plane has. (Crosswind capability = sin (sideslip angle) * speed. So the slower landing speed of the -9/A doesn't help in that regard.
The other problem is that if you try to add speed for the wind like you do in other airplanes, the -9/A will float in the flare till it finally settles down. I haven't measured it since I added the constant speed prop, but with the fixed pitch prop, 5 knots extra would be good for two seconds more float.
And then there's weathervaning tendency as you slow down. I don't have and don't want experience with this phenomenon in really strong crosswinds, but I don't think the -9/A would be any worse than the -7/A. I know that when I had the AirCam, it was a real pain to taxi when the winds got over 10 mph because the vertical fin was so big. It had to be that big to let you keep control of the airplane, single engine, at all flying speeds. Differential thrust helped only a little....
For all its other virtues, I think the -9/A is satisfactory in crosswinds, but not great. Then again, there's lots and lots of control authority in the flare in all three axes, and that helps.
Absolutely correct.
If there is one attribute of the early short wing RV models that takes some pilots a while to get used to is the strong influence of high induced drag at higher angles of attack.
As angle of attack increases, induced drag goes up dramatically. This is what has caused damage of quite a few short wing RV's over the years.
With the fantastic control response that RV's have, pilots can be lulled into feeling comfortable on approach at a speed that they feel fully in control (because the airplanes still have great control response even at very low airspeed) but is way too low to have enough energy to arrest the higher than normal rate of decent. The result is usually damaged landing gear or worse. This happens because there is no reserve energy for the round-out / flare, and as soon as the AOA is increased, what small amount of reserve energy/airspeed is left, goes away very quickly.
This is also the reason that short wing RV's don't do as well as they could in a race situation like Reno. The wing is constantly "loaded up" with G's (needing to fly at a higher AOA) and having a resultant higher induced drag than would be the case in un-accelerated flight. (this is likely the primary reason for the work being done by some to develop a tapered higher aspect ration wing).
The RV-9 has a much higher aspect ration wing so it has less of a tendency for the induced drag to increase with AOA. This is likely what makes it seem to some pilots that it will float forever compared to the short wing models.
If the amount of over speed on an aproach is the same for an RV-6A and an RV-9A... say 10 knots.... I guess the 9a would be perceived to float longer (its lower induced drag increase will make it take longer for the speed to be scrubbed off). I think this is what makes people think it is more of a floater than the short wing airplanes
But, since the stall speed is lower on the 9A, if an RV-6A and an RV-9A were fast by the same percentage, I feel that the amount of float would feel to be about the same.
Regardless, the important thing to make proper landings is to be on the proper airspeed. If that is followed, long floaty landings should never be a problem.
My comment about the-9 handling better than the short wing RV's has to do with control balance, not overall lightness. The short wing RV's tend to be overly pitch sensitive in relation to the roll axis.
It probably is slightly less capable when compared to an RV-7, but still way more capable than most of the certificated airplanes that most people are accustomed to flying.