Throt/ Rud

[Jim Ivey]

 Guys
 In this months Model Aviation (page98)Radio Control Scale Aerobatics, Peter Goldsmith has a informative article about trimming a plane and thrust. He explains that the thrust angle needed is  dependant on the airspeed and that there is a range of flight parameters that only relate to our needs so far as trimming is concerned.He has some excellant ideas here that may further tell us what we need to know, with respect to trimming thrust line and rudder trim.
It's obvious that Chips ideas work for him and Peters ideas work for him.
Grab your AMA mag. and read.

Jim Ivey 
> 
> From: "Ed Hartley" <roho2 at rcpattern.com>
> Date: 2005/01/26 Wed PM 10:34:52 EST
> To: <discussion at nsrca.org>
> Subject: Re: Throt/ Rud
> 
> Think about having the trim and thrust where you don't have to do either?????
> 
> Ed
> 
>   ----- Original Message ----- 
>   From: John Pavlick 
>   To: discussion at nsrca.org 
>   Sent: Wednesday, January 26, 2005 10:13 PM
>   Subject: RE: Throt/ Rud
> 
> 
>   Ed,
>    Don't think about inverted / upright / right / left like that. It's all the same to the airplane. Upright the slip stream hits the left side of the fin causing Left yaw. For sake of argument: Right thrust will be used to counteract this. Inverted, the SAME THING happens. Don't think right / left in reference to YOU, think left / right in reference to the AIRPLANE. When inverted the slip stream hits the left side (still) of the fin - unless the motor suddenly starts turning the opposite way. Same thrust offset ("Right") required unless the slip stream goes away in a push. Now if there's right thrust, you need left rudder to offset the right thrust which is trying to make the airplane yaw right in the absence of the slip stream air on the fin. If you still want to think about it the "other" way, remember "left" rudder when inverted will make the plane yaw to the "right" (in reference to YOU standing there watching the plane). Now I'm getting confused.
>    If you think about what Chip described: Trim for straight flight at full throttle, mix left at idle. Another way would be trim straight at idle, mix right at full throttle. That's what I've been doing. Same difference. 
>   John Pavlick
>   http://www.idseng.com
>     
> 
>     -----Original Message-----
>     From: discussion-request at nsrca.org [mailto:discussion-request at nsrca.org]On Behalf Of Edward Skorepa
>     Sent: Wednesday, January 26, 2005 8:15 PM
>     To: discussion at nsrca.org
>     Subject: Re: Throt/ Rud
> 
> 
>     I'm confused too. I know, I know I shouldn't argue with someone like chip but I believe the main reason we're putting right thrust is an asymmetric vertical fin. On most conventional airplanes the area above thrust line is much greater then area below. So, the spiraling slip stream  will hit the top portion of the vertical fin from the left pushing tail to the right thus right thrust. When inverted, the spiraling slip stream will hit vertical fin from the right because fin is now on the opposite side and  pushes tail to the left. To straighten the flight path, we need now the left thrust which is already there. During inverted push ups, why do we need to use left rudder? The spiraling slip stream misses completely vertical fin and the right (left when inverted) thrust is causing airplane to yaw left. If you have a big gasser, turn on smoke, do inverted push up and watch where the smoke goes. However, Chip's approach of fixing the inverted push ups problem is quite interesting and I'll try it on my new bird I'm working on right now.
>     ed
>       ----- Original Message ----- 
>       From: Nat Penton 
>       To: discussion at nsrca.org 
>       Sent: Wednesday, January 26, 2005 11:32 AM
>       Subject: Throt/ Rud
> 
> 
>       Cameron Smith relayed comments from Chip ( from RCU ) relating to how he uses a mix to eliminate the need for right thrust. I know Chip knows but he left me confused. Could someone clarify what he said?
> 
> 
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