RV-7A Aerobatics

[danielhv]

Saw this video on youtube... thought it was kinda neat:

http://www.youtube.com/watch?v=gVNFfTSbwAs

Now for my question... at the 2:12 mark... is he intentionally keeping the nose high? Looks kinda awkward...

[msturgis]

Looks like he is doing snap rolls.

[Low Pass]

Like Matt said, it looks like he's trying to snap the plane by looking at the rudder and elevator deflection. One thing that would make it a little more crisp and snappy would be less or even opposite aileron.

Nice video of a fun flight. But there looks like a lot of corkscrew aileron rolls. Just a personal thing.

[sandifer]

Originally Posted by Low Pass

One thing that would make it a little more crisp and snappy would be less or even opposite aileron.

No...it's in-snap aileron that helps speed up the rotation a bit. For planes like RV's and Pitts' with partial-span ailerons, half deflection or so works well. Full deflection adds too much drag. Monoplanes with full-span ailerons work well using about 1/4 deflection.

Mostly what makes a snap really go is unloading the elevator to around neutral immediately after it breaks. Watch the snap starting at 2:08 in the video - the elevator is held most of the way around. In competition, this would be called a "buried" snap. Cool video and nice air-to-air work.

[Low Pass]

Originally Posted by sandifer

No...it's in-snap aileron that helps speed up the rotation a bit. For planes like RV's and Pitts' with partial-span ailerons, half deflection or so works well. Full deflection adds too much drag. Monoplanes with full-span ailerons work well using about 1/4 deflection.

My defintion of a snap is a roll done with one wing stalled. What I saw was a tight spiraling roll.

I know without a doubt the spins tighten from a spiral to a spin with opposite aileron in the -8. As for the snap roll, I'll make a point to actually follow through on the inputs next time I'm out.

[sandifer]

Originally Posted by Low Pass

I know without a doubt the spins tighten from a spiral to a spin with opposite aileron in the -8.

Very true about spins, but spins and snaps are different animals. The reality is good snaps are typically flown with a bit of in-snap aileron.

Check out this video from Ty Frisby, an acro instructor with Sunrise Aviation who has competed in the Unlimited category. You'll see a bit of in-snap aileron.

www.youtube.com/watch?v=Gu3BfXKstJ4&feature=related

Also check out Alan Cassidy's book 'Better Aerobatics' - which is THE best acro book available, with incredibly detailed descriptions of the maneuvers.

[Low Pass]

Originally Posted by sandifer

Very true about spins, but spins and snaps are different animals. The reality is good snaps are typically flown with a bit of in-snap aileron.

Check out this video from Ty Frisby, an acro instructor with Sunrise Aviation who has competed in the Unlimited category. You'll see a bit of in-snap aileron.

www.youtube.com/watch?v=Gu3BfXKstJ4&feature=related

Also check out Alan Cassidy's book 'Better Aerobatics' - which is THE best acro book available, with incredibly detailed descriptions of the maneuvers.

And check out the French Connection's Daniel H?ligoin's Snap Roll. No aileron input. Rudder and elevator alone. Forcing the horizontal spin.

http://www.youtube.com/watch?v=6ETc1mNNQg8

[sandifer]

Originally Posted by Low Pass

No aileron input. Rudder and elevator alone.

Holy cow...that's exactly how I snap my Pitts! S-1's snap so fast, aileron doesn't have a lot of effect, so I don't bother. Never said a snap REQUIRED aileron, just that in most planes it helps a bit. But you had said OPPOSITE snap aileron helps speed the rotation, which it does not. If it does, you are clued into something world aerobatic champions are not.

Originally Posted by Low Pass

Forcing the horizontal spin.

"Horizontal spin" simply gives something for folks to relate to. Many disagree that this is an accurate description, since with a spin, BOTH wings are stalled (and stay stalled) and THEN autorotation is started by inducing yaw. Rotation occurs (much more slowly than a snap) because of the difference in DEPTH of stall between the wings.

In a proper snap roll, neither wing is stalled before the yaw is induced, but the resulting yaw quickly stalls one wing only. Because one wing is still flying, this is why in-snap aileron helps a bit...and again why it's not a true spin. However, too much aileron could unstall the down-going wing and slow the snap into a spiral. The objective of the snap is to get through it as fast as possible, with as little energy loss as possible.

Sorry, I just love talking acro.

[sandifer]

Speaking of snaps, check out this classic acro video from '86 by the late, great Bob Herendeen flying a Pitts S-1S. Most people like the tumbles and inverted flat spins - heck anybody can do a flat spin, but I like the knife-edge to knife-edge snaps. Bob was one of the best at snapping a Pitts. Wish I could do it like him...

http://airpigz.com/blog/2010/2/17/lo...ob-herend.html

[ao.frog]

Really really cool video!

Superb flying! That guy really knows his stuff! And professional made video too! Nice with timed split-screen and everything! One of the best RV-acro videos I've seen!
Anyone knows who this guy is? An ex-fighter jock maybe? Or a display pilot?

Thanks alot for sharing!