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Old Oct 22, 2002, 12:07 PM
Mitch G's Avatar
Naperville, IL USA
Joined Nov 2000
1,886 Posts
How to do an avalanche?

I have a plane that does a pretty nice snap roll. So, I want to try performing an avalanche.

I know that an avalanche is a loop with a snap roll at the top of the loop. But, what is done to actually cause the snap roll?

Do I just input right or left rudder at the top of the loop? Or, do I need to apply more elevator as well as rudder - as in a "normal" snap roll?

Are there any tricks-of-the-trade I should know about (other than being 18 mistakes high )?

Thanks,


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Old Oct 22, 2002, 01:17 PM
Purple power
gregg f's Avatar
shadow hills,ca
Joined Apr 2000
6,593 Posts
Mitch: it's a normal snap. the part that takes a bit of timing is stopping it while inverted to continue the loop. usually some down elev is needed after the snap to keep you in a nice line.

after you perfect it, try four of them in the loop. at 1/4,top,3/4 and exit.

then try it while doing an outside loop. more difficult though......gregg
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Old Oct 22, 2002, 10:52 PM
Mitch G's Avatar
Naperville, IL USA
Joined Nov 2000
1,886 Posts
By "normal snap," I assume you mean I should work both the elevator and rudder as necessary to induce the snap.

Although, I'll try various combinations and amounts of rudder and elevator, but I want to know the generally right way so that if it's not working I know it's not because I'm doing something intrinsically wrong.


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Old Oct 23, 2002, 01:52 AM
Purple power
gregg f's Avatar
shadow hills,ca
Joined Apr 2000
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yes, i tend to snap left for example my sticks would be buried in the left bottom corner..............
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Old Oct 23, 2002, 09:37 AM
Mitch G's Avatar
Naperville, IL USA
Joined Nov 2000
1,886 Posts
Thanks.


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Old Nov 07, 2002, 09:31 AM
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Alan W's Avatar
NY
Joined May 2000
2,233 Posts
Quote:
Originally posted by gregg f
yes, i tend to snap left for example my sticks would be buried in the left bottom corner..............
That includes aileron too.....!!!

Full Up, Full Left Rudder/Aileron

Some planes snap better than others....some enter the snap quiker, some take longer to exit. Playing with the CG can help this to some degree......

I've had planes that took another 1-2 revs to exit the snap once controls were released.

The key to a good avalanche is knowing your plane. Practice flying straight and level, pull up on a 45, and then bang the stix and release as soon as the snap initiates. add/subtract stick deflection time as required to exit flying straight and level.....once you have the feel for the timing on the stix, then execute it ontop of a loop

I had a plane that snapped twice before recovering.....instead of fighting it, I just did two snaps at the top of the loop


Hope this helps

Alan W
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Old Nov 07, 2002, 05:41 PM
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Gordon's Avatar
Joined Aug 2000
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It would help to know which plane you're flying, Mitch. For instance, my Tiger Moth snaps very nicely, but as it's a slow flier, it soon loses forward momentum with all the drag built up in the snap, so soon begins to fall downwards.

In an avalanche, this can make the plane enter the second half of the loop pointing downwards more steeply than it should, spoiling the roundness of the figure. That being the case, I centralise the elevator as soon as the plane begins the snap, and that helps to reduce drag, and keep the model flying a more round loop. To stop the snap I centralise the rudder.

To do 2 snaps in the avalanche, I push full down elevator as soon as the plane snaps. This down elevator removes some aerodynamic blanking from the rudder, which becomes more effective, and hence the 2 or 3 snaps.

A high-speed bipe or monoplane will behave as Alan described, and adding the down elevator during the cascade of snaps can make the subsequent snaps really violent. My heavy 20-cell Ky CAP 232 is one such.

What are you flying?

Gordon
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Old Nov 09, 2002, 09:55 AM
Mitch G's Avatar
Naperville, IL USA
Joined Nov 2000
1,886 Posts
Thanks for the extra tips. The plane in question is my Bridi Warlord 20 (Mega 22/30/3, 10x5 APC-E prop, 10x2400). I've only practiced snaps a few times. I really have to spend some quality time with the plane and learn the straight and level snap before going with the avalanche. (The last time I flew it was probably 5 weeks ago now. )

But, I appreciate the information about removing or reversing elevator input during the maneuver. Since I'm still learning the basic snap maneuver, I'm sure that I'm holding elevator until the roll is completed. I know at the end of the maneuver I've lost pretty much all my forward movement and I have to muscle the plane back into flying mode. So, I'm going to try releasing elevator at different points in the maneuver to see how that plays out. Then I'll see what kind of trouble I can get into during a loop.


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Old Nov 18, 2002, 11:54 AM
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rclark's Avatar
Butte, MT
Joined Sep 2001
7,073 Posts
You can also cheat a bit and just do a standard aileron roll (inverted to inverted) at the top of your loop which when beginning is challenging enough -- at least for me it was .
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Old Nov 20, 2002, 07:09 AM
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Mr. Wiz's Avatar
United States, MI, Fenton
Joined Jan 2000
8,542 Posts
Next time you have a plane that stalls deeply in a snap roll....as in it takes two rolls to recover.... try using less elevator to induce the snap and/or backing off the elevator completely after the roll is initiated.

A overly rearward CG can also cause a plane to bury the snaps.
Of course, I know some planes are just that way, but many times they aren't and the pilot just isn't aware of the real issue.

Wiz
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