[NSRCA-discussion] F17 barrel roll

[chuenkan at comcast.net]

If FAI/NSCRA have come up with a new definition of a barrel roll, then I can't be of any help. However, to do a "regular" old barrel roll, just do what my aerobatics student does: He is trying to learn to do 3 Horizontal Rolls (the "3 horribles). He can do one axial roll beautifully; he can often get 2 pretty good ones; but 3??? He gets the elevator miss-timed and does a very good barrel roll. So, the idea of adding elevator (plus maybe some rudder) should produce a barrel roll -- but I don't know if it would fit the NSRCA definition if said roll. From the posts, I can't tell what is required. Ah, yes, I love teaching -- that's why I gave up college tenure and went to do laboratory research. lol 

Phil Spelt, KCRC Emeritus, Secretary 
AMA 1294, Scientific Leader Member 
SPA L-18, Board Member 
(865) 435-1476v (865) 604-0541c 


----- Original Message -----

From: "Ed Alt via NSRCA-discussion" <nsrca-discussion at lists.nsrca.org> 
To: "NSRCA List" <nsrca-discussion at lists.nsrca.org> 
Sent: Sunday, August 23, 2015 8:35:05 AM 
Subject: Re: [NSRCA-discussion] F17 barrel roll 

I'm not sure , but a fter 100 years or so, it seems that the barrel roll may have a new definition. This appears to require that the model skid around the entire rotation, which is not really how a barrel roll is typically done as far as I know. I believe that you would normally do one mainly with simultaneous pitch and roll inputs, and maybe touches of rudder to keep that coordinated, in much the same way as a coordinated turn would be done in a full scale aircraft to keep the turn & bank indicator's ball centered. As a result, it would present itself as if the aircraft were traveling along the inside of a cylinder with both of it's main gear wheels always in contact with its inner surface, hence the name barrel roll. Executed this way, you could do that Bob Hoover demonstration of keeping a glass of some liquid perfectly still, resting on top of the instrument panel. 

This definition seems to be more of a variation on an integrated roll, and as a result you would expect to see the tail pointed at perhaps a 45 deg yaw angle at one point (when roll angle = 90 deg), and the nose yawed at you 45 deg at another (when roll angle = 180 deg). And I think that as a result it would also mean that the wing tip in the direction of the roll would always be in contact with the inner surface of the imaginary cylinder, instead of both wheels. Am I visualizing that correctly? It seems like it would be tricky to judge accurately. 

Ed 


Date: Sat, 22 Aug 2015 23:10:49 -0700 
To: underdw at gmail.com; nsrca-discussion at lists.nsrca.org 
Subject: Re: [NSRCA-discussion] F17 barrel roll 
From: nsrca-discussion at lists.nsrca.org 

Hopefully this helps… 





From: NSRCA-discussion on behalf of NSRCA List 
Reply-To: Daniel Underkofler, NSRCA List 
Date: Saturday, August 22, 2015 at 6:21 PM 
To: NSRCA List 
Subject: [NSRCA-discussion] F17 barrel roll 

In F17 there is a cryptic aresti symbol that is described in the figure description as a barrel roll. Will somebody please describe this in more detail and what control inputs will obtain the required result? 

Thanks, Dan 
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