RV7-RV9

[RVbySDI]

Originally Posted by workky

I apologize for kicking off a firestorm here. I was just curious what made it stronger.

There is that statement from you again. That is what is "kicking off a firestorm"! To say that the 7 is "stronger" is just not the appropriate way to think about the two planes.

Originally Posted by workky

I really like the fact the 7 is faster and appears to have more useful load, but it might be twitchy on the stick, which I guess is something you get use to.

The useful load of the 9 is not necessarily different from the 7. I carry just as much in my 9 as does a 7. There are other weight considerations in addition to useful load to consider also. The CG can potentially be different for the two airplanes. A 7 (or a 9) can end up with CG issues that can affect the useful load of the plane.

As for speed, well, I would expect a 7 with constant speed will out climb my 9 with fixed pitch but as far as standard cruise speed, I fly just as fast in cruise as my 7 buddies and burn less fuel doing it.

Originally Posted by workky

All though aerobatics are not very appealing to me right now, one day with the proper training it might be fun to roll, and loop. And I could see that happening

If that is what your mission is then that should drive your decision and that decision would take you to the 7. I think you will be very happy with whatever you choose.

[Vansconvert]

From what I saw on the display board at Oshkosh the seven has a considerably faster rate of climb than the 9.

[Kyle Boatright]

Originally Posted by Vansconvert

From what I saw on the display board at Oshkosh the seven has a considerably faster rate of climb than the 9.

With its reduced span loading, a -9 will outclimb a -7 if the aircraft have the same firewall forward package and are at similar weights.

[PilotjohnS]

Well most 7s have an 360 and CS in the nose and most 9s a 320.

In my opinion, the longer wings make for slower landing speds and more fuel efficient high altitude cruising. Inwould expect the 7 to be faster down low, higher climb rate and acro.

Pick what you want accordingly.

[RVbySDI]

As I already stated earlier, I fly with several buddies that have RV7's. Several with constant speeds and IO-360 setups. One with O-360 and fixed pitch Catto. Climb equally with the fixed pitched 7, although he sometimes has cooling issues where I don't. No question the constant speed guys out climb me. However, when we level out in cruise we will all see similar cruise speeds. When doing same speeds I will end up burning less fuel. They can go faster than I if they increase power and burn more fuel, but then so can I. If we get above 10.5 or especially 12.5 I think I can begin to outpace their speed also. However that has never been put to the test. Truth is the 7 does have a higher top speed than a 9 but not sure how that top speed fairs up high compared to a 9.

Flying back from OSH yesterday with 7 buddy with IO-360 constant speed prop we were side by side for 3 hours. The first half of our flight to our fuel stop at 6500, the rest of the way at 8500 before landing for fuel. Identical speeds the entire way. I burned 21 gallons, he burned 25 gallons.

P.S. Just in case readers have not noted my 9A configuration. I have an IO-340 with Catto fixed pitch 3-blade (68 X 74) prop. Slick mag on left, Lightspeed Plasma II on right; forward facing cold air induction; Vetterman 4 straight pipes.

[Caveman]

Originally Posted by RVbySDI

Flying back from OSH yesterday with 7 buddy with IO-360 constant speed prop we were side by side for 3 hours. The first half of our flight to our fuel stop at 6500, the rest of the way at 8500 before landing for fuel. Identical speeds the entire way. I burned 21 gallons, he burned 25 gallons.[/i]

Not quite Steve. Remember I didn't fill to the top at Oshkosh due to trying to keep fuel from venting overboard in the heat, but I did at K81. There is no doubt I used more fuel but it wasn't that dramatic. In years past it was more in line with a few tenths per fuel stop. There is no way I burned 4 gallons more in a 3 hour flight. I'd be surprised if it was a gallon.

[RVbySDI]

Ok. I stand corrected on yesterday's flight. However in past flights, not necessarily with you, the differences have been more than a few tenths of a gallon. The point I have wanted to get across on this thread is that if someone is looking to build a 9 they can build it to the point where they can fly cross country with 7's and not be left behind in the dust. I still think the fuel burn for the 9 is less than the 7 given comperable flight parameters, however slight they may be. I wish I had a constant speed. Then we could do closer comparisons.

All in all, everyone ends up building what they think works best for them. I don't think anyone looking for cross country flying is going to go wrong with either plane.

[Snowflake]

Originally Posted by RVbySDI

There is that statement from you again. That is what is "kicking off a firestorm"! To say that the 7 is "stronger" is just not the appropriate way to think about the two planes.

Even if it's correct? Structurally, it is definitely stronger. The gross weight and G loading limits show that to be true.

[MercFE]

Could sell you a lead weight.

Structurally, it would be stronger... But, you probably wouldn't be able to fly it very well.