eric_marsh
Well Known Member
I have been thinking of building a RV-7 but the more I look at the 9 the more attractive it looks. I realize that it is not designed for areobatics but is it suitable for some occasional less intense loops and things?
I have been thinking of building a RV-7 but the more I look at the 9 the more attractive it looks. I realize that it is not designed for areobatics but is it suitable for some occasional less intense loops and things?
Fuel efficiency. My 6A with it's 0360 can do just as well as a 9A with it's 0320, if we both fly at conservative airspeeds. This is kind of a surprise, but is factual, as I've compared with several "well built" 9's. However, as said before, I can still climb and out run the 9, if desired.
"...and is slower on the top end".
Is that true at altitude as well? I would have thought the "9A" would allow it cruise faster at altitude than a "6" or "7" due it it's higher aspect ration wing at simliar power setting...is that not true?
If you compare an exact same engine / prop combination installed on an RV-9A and an RV-7A with the airplanes finished to an equal level of quality and with the same empty weight, The RV-9A will take off and land shorter, will climb initially climb about the same but then do better than the 7 at higher altitudes. At high cruising altitudes (above 8500') the 9 will be as fast or slightly faster (depending on how high you go). The RV-7A will be slightly faster (about 3 MPH) if comparing top speeds at lower altitudes.
Keep in mind that it is really no surprise that an RV-6A with an O-360 will out climb and out run an RV-9A with an O-320.
I would like to see a comparison between mine and an 0360 equipped 9, but we'd both have to have C/S props.
L.Adamson --- RV6A
Yes and no... If you're comparing full-throttle operation, then yes, the comparison is moot. But if you're comparing fuel flow at equal airspeeds, or have a way to determine that you're both at the same output power when flying side-by-side, then the comparison is totally relevant. If you're flying a 180HP RV-6 throttled back to 150HP, and a 150HP RV-9 wide open, you've got a fair comparison (assuming the same pitch and diameter of prop). The only difference is that the -6 is carrying an extra XX pounds due to the slightly heavier engine.In my mind, it is not even relevant to say that "my 6A can out run an RV-9A" when comparing performance of the different models, if they do not have the same engine / prop. combination.
That is not much different than saying my 180 HP RV-6A can outrun a 160 HP RV-6A. Something to be expected I think.
If you're flying a 180HP RV-6 throttled back to 150HP, and a 150HP RV-9 wide open, you've got a fair comparison (assuming the same pitch and diameter of prop).
Eric,I have been thinking of building a RV-7 but the more I look at the 9 the more attractive it looks. I realize that it is not designed for areobatics but is it suitable for some occasional less intense loops and things?
In my mind, it is not even relevant to say that "my 6A can out run an RV-9A" when comparing performance of the different models, if they do not have the same engine / prop. combination.
That is not much different than saying my 180 HP RV-6A can outrun a 160 HP RV-6A. Something to be expected I think.
That really isn't the point, though. I have the reserve power to outclimb and outrun the 9 with it's 160, yet I can throttle back & still be as stingy on fuel.
We're also carrying near identical loads. That makes my performance overall.........the better.
L.Adamson --- RV6A
Scott,It will still be a few months before my new RV-9A with a 260 HP fuel injected Lyc IO-540 is flying, but once it is I am sure I will be able out climb and out run you but I will still be able to throttle back and match your fuel economy; and the extra power will easily offset the extra weight...
Climb rate and speed are indeed two aspects of performance, but "overall" there are many others....I have the reserve power to outclimb and outrun the 9 with it's 160, yet I can throttle back & still be as stingy on fuel.
We're also carrying near identical loads. That makes my performance overall.........the better.
L.Adamson --- RV6A
It will still be a few months before my new RV-9A with a 260 HP fuel injected Lyc IO-540 is flying, but once it is I am sure I will be able out climb and out run you but I will still be able to throttle back and match your fuel economy; and the extra power will easily offset the extra weight...
I realize that the RV9 was not "designed" for aerobatics however the RV9 and the RV6 both have a max Utility category weight of 1600 lb.(+4.4G/-1.75G), which means they can both take the Utility category G loads at 1600 lb. So why is it OK to have an approved aerobatic weight of 1375 lb for the RV6 but no similar approved aerobatic weight for the RV9. If they can both handle the same G loads at 1600 lb why can't they both handle the same G loads at 1375 lb.
Fin
9A
Any thoughts on this question?
The leaner mixture settings up there and the smoother ride are what the Roncz airfoil wings are all about.
Well, apart from the other issues, some simple maths would show:I realize that the RV9 was not "designed" for aerobatics however the RV9 and the RV6 both have a max Utility category weight of 1600 lb.(+4.4G/-1.75G), which means they can both take the Utility category G loads at 1600 lb. So why is it OK to have an approved aerobatic weight of 1375 lb for the RV6 but no similar approved aerobatic weight for the RV9. If they can both handle the same G loads at 1600 lb why can't they both handle the same G loads at 1375 lb
the answer is they cannot handle the same at 1600lbs, the RV-6 can handle more. Just there is not a "category" for +5.16g. so it is downgraded to the Utility limits...If they can both handle the same G loads at 1600 lb why can't they both handle the same G loads at 1375 lb
Thanks for the reply. Sounds like the RV-7 may be my best choice. I was attracted to the idea of greater fuel efficiency but you seem to have more or less negated that.
My gut feeling is that 90% of the time or more the RV-9 would be a fine choice, but if I do want to explore the world of aerobatics somewhere down the road it would eliminate that possibility.