[Rick6a]

As I complete final assemby work on the RV-8 project, I enjoy the uncommon luxury of constantly making side by side comparisons with "Darla!" my RV-6A parked just feet away. Last week, as I walked past her hand carrying an -8 aileron unloaded from my truck, I couldn't help but notice a size difference. As a data point, the wing span on the -6 series is 23', an -8 comes in at 24 feet. I laid the aileron atop the wing. Sure enough, the -8 aileron is 6" longer. I love the quick responsiveness of the ailerons on "Darla!" and would never want to go back to anything less. If anything, I would desire even more. So I address this question to the experienced RV driver who has personally compared the two in flight.....can I anticipate the increased length of the -8 aileron will translate into an even faster roll rate?

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[Andy Hill]

I was teaching a -6 driver formation last weekend... and it developed a problem. So put him in the back of our -8 and did it that way.

Lots of over-controlling in roll, and comments that it was "much more sensitive".

Also heard comments that roll rate etc. in the -8 is better than the -7... despite same ailerons.

So I think you will be pleasantly surprised

Andy
http://www.g-hilz.co.uk

 

[flyeyes]

RV driver who has personally compared the two in flight.....can I anticipate the increased length of the -8 aileron will translate into an even faster roll rate?

Short answer is "not really."

I have an -8 with an angle-valve IO-360 and a CS prop. I've flown an -8A with a parallel-valve 360/CS.

Every -6 or -6A I've flown has had an O-320/FP setup. The only -4 I've flown had an O-320 with a wood prop.

The differences in handling between all the RVs I've flown are tiny, but consistent. The -8s feel slightly more "substantial" and have slightly higher control forces. I suspect this is largely because they have bigger motors and heavier props. They also tend to have a more forward CG which makes them a little more stable.

I think the taller vertical stab on the -8 (and -7) tends to lower the roll rate a little, but improves directional stability and the ride in turbulence. The -8s don't have any of the "Dutch roll" tail waggle that some -6s have in chop.

Ultimately, you really have to be looking for control feel differences to even notice them--we're talking tiny shades of difference here.

 

[Ironflight]

I have been swapping back and forth between the Val (-8) and Mikey (-6) for the past year, and while I haven't measured absolute roll rate, the -6 always just feels a bit "lighter" - so I think I agree with James - the -8 just feels more substantial. Now I did fly Jay Pratt's -8 last fall, and for some reason, it felt lighter in roll than my -8, and I think that Danny King noticed the same thing when he compared it to his. I'm still not sure why that would be the case, but it will be interesting to hear your own comparisons when you fly it Rick!

Paul

 

[osxuser]

I don't know if this has any bearing on the -8, but someone on the boards mentioned that Van's changed the ratio of the bellcrank movement for the ailerons on the -7 to make them more sensitive. Could this be the difference between the different -8's too?

 

[jthocker]

roll rate

I think the differences in roll rates, or "lightness" might be attributable to different trailing edge radius's of the ailerons.
I had the chance to fly a friends RV4 today.(12 years since I flew my last RV4). We were troubleshooting a heavy wing on his recently purchased RV4. After checking the rigging with an old fashioned airfoil template, we found some minor twisting of flaps and ailerons but no mis-mounting of the ailerons. I decided it would be best for me to fly it to decide if some aileron squeezing might be of some benefit.

We traded planes and went flying, the really cool thing about this was;
He showed me how to start his plane and then we went over and I showed him how to start mine. There was no talk about insurance, liability, etc.
2 professional aviators respecting and trusting each others abilities to just figure things out.

We flew, and to me the 4 did not feel any more nimble than the 8.
I wonder when someone says that a certain model is lighter in roll than another,
that it could possibly be that the "lighter" one had fatter trailing edges than the other one.