Displacement during snap rolls (was Why is it so quiet?)

[Dean Pappas]

Jerry,
I have no problem with a dead slow snap, as long as all the elements are there.
An outside snap at the top of an inside loop may be very slow, if the plane is decellerated to near the level flight stall speed, at the top.
If you do a snap at just above landing speed, how fast is the rotation? Relatively slow, I'll bet.
 
Not zeroed, but downgraded. 1 point per 15 for the extra yaw, and a downgrade for loss of smoothness/gracefulness.
The snap itself may be violent, but the approach and departure should be graceful.
Regards,
 

Dean Pappas 
Sr. Design Engineer 
Kodeos Communications 
111 Corporate Blvd. 
South Plainfield, N.J. 07080 
(908) 222-7817 phone 
(908) 222-2392 fax 
d.pappas at kodeos.com 

-----Original Message-----
From: discussion-request at nsrca.org [mailto:discussion-request at nsrca.org]On Behalf Of Jerry Voth
Sent: Wednesday, December 29, 2004 4:21 PM
To: discussion at nsrca.org
Subject: Re: Displacement during snap rolls (was Why is it so quiet?)


How would you judge a snap that meets all the criteria that has been mentioned in this thread that constitutes a good snap but takes almost a full second to complete?
 
I also was at the T.O.C. when the guy that won used opposite rudder just prior to his vertical snaps-as I recall it was a very quick move. Wouldn't they be zeroed using the current thinking because the initial break was sideways before the up break?
 
kJerry

----- Original Message ----- 
From: Dean  <mailto:d.pappas at kodeos.com> Pappas 
To: discussion at nsrca.org 
Sent: Wednesday, December 29, 2004 3:10 PM
Subject: RE: Displacement during snap rolls (was Why is it so quiet?)

After re-reading the post, it occurred to me I should clarify:
I was writing about what I thought a good standard might be.
For right now, the book is it, and as Bob pointed out, there is no specific track downgrade.
Anyone have an IAC judges' guide handy? I'm curious.
By the way, the full scale guys do horrible things to snaps, including completely unstalling the plane (particularly during consecutive snaps).
That don't make it right!
Archie has a good point, not only does the standard need to be better nailed down, but some people may never be trained to "see fast". 
Add in some "tired from 4 hours in the chair" and you have mush.
 
This is a good discussion!
 
 
Dean Pappas 
Sr. Design Engineer 
Kodeos Communications 
111 Corporate Blvd. 
South Plainfield, N.J. 07080 
(908) 222-7817 phone 
(908) 222-2392 fax 
d.pappas at kodeos.com 

-----Original Message-----
From: discussion-request at nsrca.org [mailto:discussion-request at nsrca.org]On Behalf Of Dean Pappas
Sent: Wednesday, December 29, 2004 1:15 PM
To: discussion at nsrca.org
Subject: RE: Displacement during snap rolls (was Why is it so quiet?)


Hi All,
before I crawl back to the lab ... and see what's on the slab ...
 
While I agree that some displacement is inevitable, I wouldn't want to see a rule that says that if you don't see any, then it's not a snap.
The very best high energy snaps will displace so little that it will be really hard to say that it's there.
 
1) My guess would be that most really good snaps probably displace about 1/2 wingspan, both up and to the side.
Gravity will possibly kill any evidence of the UP part. Try doing an inside snap from inverted, or try a snap from knife edge. You'll see the UP displacement! 
2) As the elevator throw is reduced, from that needed to do a good snap, the airplane displaces worse and worse, as it takes longer for the plane to stall deeply enough, to make little enough lift to continue changing the airplane's course appreciably.
3) If the elevator throw is further reduced, the displacement goes away! Hmm.
4) Leading the elevator reduces the necessary amount of throw, for a good snap. 
 
Here's the aesthetic question behind the argument:
Do we all agree that when you see a snap with an "in your face" break that it really is a thing of beauty?
Or do some of us think it's untidy, and not"on a line"? I had a judge ask me (back in '91) "What's with the twitch before the snap?"
 
I'm as confused as anybody. I guess that's as good a way to start the new year as any.
 

Dean Pappas 
Sr. Design Engineer 
Kodeos Communications 
111 Corporate Blvd. 
South Plainfield, N.J. 07080 
(908) 222-7817 phone 
(908) 222-2392 fax 
d.pappas at kodeos.com 

 

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