Posted Wednesday, July 7, 2010 @ 07:02 AM  

You/we have to be very careful here, because the Avalanche incorporates a snap/flick roll, and these are expressly forbidden in Fourniers, even in an RF4.

However, we do know (because we have film evidence) that RF4s and RF5s (but not RF5Bs) have been flick-rolled /snap-rolled for over forty years.

First, make sure all your fin, stabilizer, elevator, wing, and rudder attachments are secure, not only to one another, but also to the wood within the structure. DO NOT SKIP THIS STEP. Snaps may only register 3.5g or so, but they impose huge torsional stresses on the airframe.

Rene's test pilot Bernard Cheauvreau told us, "Never snap roll above 120kph" Work this out for yourself, but I seem to remember that 120 kph is around 65 knots or 75 mph BUT CHECK THIS VERY CAREFULLY.

I tried many level snap rolls, starting at maybe ten knots slower and working upwards to that kick speed.

I found that the stick wants to move sideways in your hand, and that letting it do so improves the snap.

I found that if you 'unload' the snap stops immediately.

I found that if your nose is at all above the horizon the snap will stop before a 360-degree rotation.

I found it snaps better to the right than to the left (although it can sometimes be more erluctant to recover).

I found that, to initiate the snap, you need simultaneous full back stick, full right rudder and full right aileron.

I found that, to stop the snap, you need simultaneous full left rudder, some left aileron and nearly full forward stick.

I found that sometimes, for no apparent reason, the snap will continue rotating into a full-blown spin and turn through another 180 to 360 degrees (with consequent height loss) before stopping. I don't know why, it doesn't often happen, but it's scary when it does.

I fly a tight loop from 130 mph, pulling quite hard all the way around, so that the nose is just coming down towards the horizon as the speed gets to snapping speed. Then I hit the 'initiate' inputs at precisely that speed and no higher.

A second or so later, just before 270 degrees of rotation, I hit the 'recover' inputs.

This is not a proper Avalanche, because the snap is not symmetrically disposed around the top of the loop, but rather starts at the top and finishes in a vertical nose-down attitude 3/4 the way around the loop (and nearly stationary in the air). However, to fly a better one I would need to snap at a higher airspeed, and that would be madness in a 43-year-old airframe.

That's all I can say Sam, except 'Don't do it'.

I am an old guy, I've raised my kids and had lots of fun in my life, so if my airplane flies to pieces under me, I've only got myself to blame and I was having fun.

If your airplane flies apart, your folks, your buddies and lots of other people, myself included, would be horrified and apalled.

Take care, think very hard about this, and talk it through with your folks before trying an Avalanche.

Posted Tuesday, July 13, 2010 @ 04:38 PM  

All went well (As the late Pete Goldin said "-It's one strong Airy!" but I haven´t tried it consciously since. As Bob's description hints I think you have to work your way up to it methodically and feel confidently proficient in the aerobatic basics first.

May the 4's be with you/ Jörgen

Posted Saturday, July 24, 2010 @ 12:21 PM  

That's great. Well done.

Have you seen Bob Hart's composite footage of my Red Bull flying in May?

http://www.youtube.com/watch?v=pVHX0kJxGjU

It is very low resolution, but you can kinda see both my control inputs and the external result.

I will try your technique tomorrow, on my way to the Windermere display.
Washed out today, because I could not get over the hills because of low cloud and drizzle -- typical British summer weather!

Enjoy, but remember that 120kph maximum flick speed (and if you're doing them on a down-line, you want to be even slower for the kick).
And I use ten knots slower for the half-flick to the inverted, because that's all you need.

Have fun and stay safe.