YA P-47 Trim  
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All Forums >> RC Airplanes >> RC Warbirds and Warplanes >> YA P-47 Trim
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YA P-47 Trim - 6/11/2003 11:56:31 PM   
edp



Posts: 126
Joined: 11/4/2002
From: N. Canton, OH, USA
Status: offline 		I have been flying a YA P-47 with a G-38 and have had no trim problems in pitch. We now have gone to a G-45 and the trim is all over the place. The model is balance as before the engine swap. I am adding almost full down trim for level flight at full throttle. Take-offs and landings are horrible with the down trim, with the tail coming up or not setteling down.
We have checked the balance and thrust angles. We added a 1/16" down thrust on the engine and that helped a little, but I am still adding a lot of trim. One thought is to mix throttle and down trim together and put it on a mix switch. Off during gear down (take-offs and landings) and on during gear up flight.
Any other ideas? The bird is 23#(full blown scale) and flew decent with the G-38, but better with the G-45. What are the guys with the G-62s doing? Any help or advise will be appreciated.
       Post #: 1

YA P-47 - 6/12/2003 12:00:12 AM   
BobH


 

Posts: 4418
Joined: 4/1/2003
From: Springfield, VA,
Status: offline 		Ed, I too have heard about trim probs with that plane. I dont have an answer but I await an explaination.. I plan on putting a 3.2 in mine very soon.. I suspect it will be in the 23-24 lb range also.. BobH.

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       Post #: 2

YA P-47 Trim - 6/12/2003 12:08:06 AM   
edp



Posts: 126
Joined: 11/4/2002
From: N. Canton, OH, USA
Status: offline 		If you haven't mounted the wings and stab yet double check the incedence, it may lie there. Ours are solidley set and cannot be changed.

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       Post #: 3

YA P-47 Trim - 6/12/2003 12:17:09 AM   
Ham639



Posts: 230
Joined: 2/22/2002
From: Buchanan, MI, USA
Status: offline 		edp,
I too have been flying a YP-47 now for about 4 years with a G-45 swinging a 22x6-10 prop. I have no pitch changes at all! I balanced mine slightly nose heavy (it only took 6 oz. do do this). I do have about 1/8" of down thrust in mine, no right thrust. I hope this helps. Let me know how it goes, I think we can get this thing ironed out for you.
Chuck

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       Post #: 4

YA P-47 Trim - 6/12/2003 12:19:18 AM   
Ham639



Posts: 230
Joined: 2/22/2002
From: Buchanan, MI, USA
Status: offline 		edp,
just a thought, is your elevator push rod flexing with the extra power?
Chuck

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       Post #: 5

YA P-47 Trim - 6/12/2003 12:29:18 AM   
AirRayInc



Posts: 922
Joined: 12/30/2001
From: San Pedro, CA, USA
Status: offline 		G-62 for me, 3.2 for friend, 4.2 for a customer and a upcoming 4.2 for me. No pitch changes. Thats tough one, without seeing or flying the airplane. Flex in the elevator rod as mentioned, or a major change in the engine thurst angle.

Weird man,
Ray

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       Post #: 6

YA P-47 Trim - 6/12/2003 1:19:08 AM   
edp



Posts: 126
Joined: 11/4/2002
From: N. Canton, OH, USA
Status: offline 		We checked the arrowshaft pushrods and they are tight with no flex. My first thought was 1/8". We would have to do some serious rework of the cowl due to the dummy engine to get it. We are using a 22x6-10 prop it pulls great. We also have added 8oz. of lead to the front lip of the cowl. I fly mostly pattern birds, so flying is easy but trimming is an art!
Thanks guys,
Ed

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       Post #: 7

YA P-47 Trim - 6/12/2003 1:32:52 AM   
edp



Posts: 126
Joined: 11/4/2002
From: N. Canton, OH, USA
Status: offline 		Here are a couple shots of the P-47 and Harvard

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       Post #: 8

YA P-47 Trim - 6/12/2003 1:33:49 AM   
edp



Posts: 126
Joined: 11/4/2002
From: N. Canton, OH, USA
Status: offline 		close up

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       Post #: 9

YA P-47 Trim - 6/12/2003 1:34:45 AM   
edp



Posts: 126
Joined: 11/4/2002
From: N. Canton, OH, USA
Status: offline 		Harvard at rest

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       Post #: 10

YA P-47 Trim - 6/12/2003 1:35:21 AM   
edp



Posts: 126
Joined: 11/4/2002
From: N. Canton, OH, USA
Status: offline 		and at play

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       Post #: 11

YA P-47 Trim - 6/12/2003 2:28:54 AM   
paladin


 

Posts: 1656
Joined: 2/13/2002
From: Vestal, NY, USA
Status: offline 		Ed, do you work the throttle while flying? I'm assuming with the extra power you were flying at less than full throttle? If so in loops and other maneuvers you are working the throttle. If that sounds right, do the trim changes come with the change in throttle setting? If this sounds about right it is leading to Engine thrust angle.

There is a test to check for engine thrust angle. Trim the plane for full throttle (if you can) then set up a level full power pass at about 1.5 mistake hight. When the plane is right in front of you bring the throttle to idle and watch what the plane does. It should gently settle as the speed bleeds off. If it veers up or down the engine pitch has to be moved in the direction it veers.

I hope this helps
Joe

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       Post #: 12

YA P-47 Trim - 6/12/2003 2:59:27 AM   
edp



Posts: 126
Joined: 11/4/2002
From: N. Canton, OH, USA
Status: offline 		It drops quickly and I almost run out of elevator during landing. The engine is new and I don't have a good midrange yet. My goal is to be able to do the scale figure 8 without worry at half throttle and half flap. I still jocky the throttle during approach to maintain a flat sink rate (too many years of pattern flying). As speed bleeds off, I'm pulling up to slow the bird down. With the down trim in it, I run almost out of elevator. This is why I'm thinking if mixing.

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       Post #: 13

jug - 6/12/2003 7:17:47 AM   
fw190d9



Posts: 507
Joined: 12/15/2001
From: Seguin, TX, USA
Status: offline 		Ed, The yellow jug wing develops a TON of lift. The extra power from your G-45 neccesitates an elevator neutral point change. I had one with a G-62 and my neutral point had the bottom surface of the elevators level with the bottom of the horiz stab. Put your transmitter trim at neutral and set the elevator( by adjusting the pushrod length) so that at its neutral point it equals what you used to have trimmed in. Make sure you compensate and add more throw to equal what it was previously at max elevator throw. Some may disagree with this but its easier than changing the incidence on your stabilzer.
Evan Q.

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       Post #: 14

YA P-47 Trim - 6/13/2003 12:57:09 AM   
edp



Posts: 126
Joined: 11/4/2002
From: N. Canton, OH, USA
Status: offline 		FW190-D9
If I do this, will I not be carring down trim during take-off resulting in a nose-over?

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       Post #: 15

YA P-47 Trim - 6/13/2003 1:56:10 AM   
paladin


 

Posts: 1656
Joined: 2/13/2002
From: Vestal, NY, USA
Status: offline 		Ed, you said that you pattern fly, do you have any of the pattern trim charts? I'd start there, with every new plane and it can take quite a few flights to get it right. But from what you described I would look at engine thrust angle (ETA) first. If our ETA is not c