[NSRCA-discussion] Rudder mix instead of right thrust?

[Dean Pappas]

Hello Vicente,
The trimming adjustment procedure for right rudder with throttle couple I will describe was developed with the Excelleron that I reviewed for Model Aviation. I synthesized this method, based on the several different methods I heard described. As Jason said, some of them did not fly right. The Excelleron is a very good flier, and with a dependable muffled 120 two-stroke I would use it a low-hassle practice ship. Like most airplanes, it required about 2-3/4" of right thrust and a small amount of right rudder to make the plane trim normally. The predictable unwanted effects in spin entries and loops (especially the outsides) were present but not unusually bad.
 
So what I did was 
1) Set the rudder dead straight and not touch the rudder trim lever again.
Confirm that this is really the middle with repeated upright and inverted stalls/spin entries, to make suer the plane does not have a bias to either side.
2) reduce the right thrust to a "guess" setting that is enough for whatever throttle setting and speed you fly your normal level lines.
You test this with shallow climbs at 2/3 throttle,  and small loops at that same throttle. I ended up with about 1-3/4 degrees. 
3) Set up a throttle into rudder curve mix and keep the percentages at zero from idle up to 2/3 throttle. Then add a slop from there to full throttle,
and adjust those upper coupling ratios to get a straight vertical line.
 
 
Limitations: 
Never fly above 2/3 throttle in level flight.
Never push the throttle up too soon before pulling or pushing to a vertical.
Avoid sudden throttle changes
 
In other words, this is not appropriate if you have not mastered purposeful throttle management.
 
Hope this helps,
Dean P.
 
 

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: vicenterc at comcast.net [mailto:vicenterc at comcast.net]
Sent: Monday, February 20, 2006 4:58 PM
To: NSRCA Mailing List; NSRCA Mailing List
Cc: Dean Pappas
Subject: Re: [NSRCA-discussion] Rudder mix instead of right thrust?


Dean,
 
Could you paste the article here?
 
Thanks,
 
Vicente Bortone
 

-------------- Original message -------------- 
From: "Dean Pappas" <d.pappas at kodeos.com> 

> I wrote about the throttle-rudder couple trimming procedure in FM about nine 
> months ago. 
> I also described the shortcomings for those pilots still learning optimal 
> throttle use. 
> Dean Pappas 
> 
> -----Original Message----- 
> From: nsrca-discussion-bounces at lists.nsrca.org on behalf of George 
> Miller 
> Sent: Sun 2/19/2006 11:08 AM 
> To: NSRCA Mailing List 
> Cc: 
> Subject: [NSRCA-discussion] Rudder mix instead of right thrust? 
> 
> 
> Somewhere I've seen a description of Jason's technique to set up rudder 
> mix instead of right engine thrust, but I can't find it. Could someone please 
> re-post this or re-iterate it. I can't believe I didn't save the message!-DOH! 
> 
> I can set up the mix in the transmitter...what I really want to know is 
> what starting percentages are reasonable, and how to fine tune the mix. 
> 
> thanks, 
> 
> George 
> 

-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://lists.nsrca.org/pipermail/nsrca-discussion/attachments/20060221/a4e7f7b9/attachment-0001.html