weight and balance ?

[Mark Browning]

I am about to order my finishing kit and engine.
I have decided to install a 180hp IO- 360 with a fixed pitch prop.
A guy i know who flys a RV7 says that the center of gravity is way back on his airplane, he has 180hp IO- 360 with a three blade hartzell c/s prop.
Has any one heard of this problem with c/g position ?

[jim_geo]

Good choice on the engine prop combo. I'm doing the same. There are few parts not needed because of the fixed pitch prop that I think lead to some confusion on the part of the person pulling the parts at Van's. When I started using the parts from the firewall foreward kit I found they had sent me a bag of hardware for an O-360. Even during an inventory of parts this may not be obvious until you actually start using the parts. Both parts lists come with the large bag of hardware and depending upon which engine chose, you choose the list.

[svanarts]

This is exactly why I'm going with a Constant Speed prop on my RV-7. I've heard the RV-7 can be a smidgen tail heavy. I haven't gathered too much data on this because doing weight and balance is way in the future for me. I fly an RV-4 right now and I'm tired of the tail heavy problem. It's only an issue in the -4 when carrying heavy passengers. In the RV-7 it will only be an issue carrying baggage.

My RV-4 has an O320 and a wood prop. I installed a Landoll Harmonic Dampener. This adds 12 lbs right on the nose almost as far forward as you can get which helped my CG a bit. You might consider that. If you are going with a metal prop that will help a bit too.

[captain_john]

The -7 is tail heavy.

Check out:

http://www.rvproject.com/wab/

for some really good W&B info.

CJ

[Mark Browning]

I am about to order my finishing kit and engine.
I have decided to install a 180hp IO- 360 with a fixed pitch prop.
A guy i know who flys a RV7 says that the center of gravity is way back on his airplane, he has 180hp IO- 360 with a three blade hartzell c/s prop.
Has any one heard of this problem with c/g position ?

Hi Guys
Bruce at Vans gave me some info regarding this issue here is his comments :-
Since the 160 weighs less than the 180, we made the engine
mount 2" longer to compensate. So in the end I don't think there is
any real difference in CG. We built our RV-7 that's used for
transition training with a 160 and FP prop and since we didn't have
a 160 mount available, we put a 180 mount on the plane. Even
though it is 2" short, it seems to do OK although is is a little tail
heavy and Mike has to be careful with the weight and balance when
packing for long trips. Many -7's have been built with the 180 and a
FP wood prop and they do just fine. What ever fits your budget is
the way to go. The 180 with a FP metal prop will not be tail heavy.

[svanarts]

Good info. Thanks for posting that.