Trim

Post-War Aeronca Champ airplanes
sparky66
Posts: 22
Joined: Wed Aug 04, 2010 18:35
Contact:

Re: Trim

Post by sparky66 »

We adjusted all travels at last annual according to specs(Lasher C-85 STC), and there is still not enough trim when solo in front seat. This appears to be normal. It is not uncomfortable, or too heavy, but it is not trimmed.

CF-KYE
Posts: 44
Joined: Sat Sep 17, 2005 09:43
Location: Lacombe, Alberta, Canada
Contact:

Re: Trim

Post by CF-KYE »

My 7CCM is the same, but I'm on the big side, too. Plus I have a 7EC engine mount (almost 2" longer than the original), starter, alternator, battery, Hanlon Wilson exhaust... it all adds up. Solo from the back seat or with a 180lb passenger I can trim for 65 mph. At least all my gas is in the wings. My buddy's 7BCM is the very same. I might go back to the short engine mount one of these days, but I need to figure out if everything will still fit first.

jc pacquin
Posts: 530
Joined: Wed Jan 11, 2006 21:12
Location: baltimore, md.
Contact:

Re: Trim

Post by jc pacquin »

I had 2 Cessna 140's and a 7BCM with starter, generator, metal prop. Alot of the time, alone, I would forget to trim on downwind and land with trim in neutral on all three aircraft. I flew all three the same, 70 in the pattern, 60-65 on final to a three point. stick or wheel all the way back, full stall, plop onto runway or grass. I was landing on 2200 feet so I had plenty of room. There never seemed to be a problem. I very rarely trimned any of them full nose up. JP

MikeB
Posts: 3255
Joined: Wed Nov 17, 2004 17:07
Location: Western Wisconsin
Contact:

Re: Trim

Post by MikeB »

During a gusty wind over the trees and my head 'somewhere dark' a few days ago, I was still floating down our 2100' runway and decided I needed to go around (never be too proud to go around). Trim was all the way back or full nose up, such as it is, and it was just a matter of full power, move the stick forward to pick up speed and then sliding the trim forward once the angle is established but it took no effort unlike what I remember of the Cessna 150 or my 140 Piper with the crank on the ceiling where you had to fight the trim until things got cleared up.

Mostly with the nose heavy L16 it seems I just have to concentrate more on maintaining an approach speed of around 60 but because it's often necessary to slip over the wires and trees while loosing altitude it's real easy to pick up speed and go floating down the runway.

MikeB

gusc
Posts: 590
Joined: Tue Jan 31, 2006 01:16
Location: Ash Flat, AR
Contact:

Re: Trim

Post by gusc »

Flaps make the difference. Almost any airplane with full landing flaps will require mucho muscle forward pressure in a full throttle go-around. Small Cessnas won't climb with full flaps and full power.

We don't have that problem in Champs even with full 65 hp!
Gus Causbie
Ash Flat, AR
N83564, 7AC-2235, A65-8

Bo Grave
Posts: 23
Joined: Wed Jul 07, 2010 09:06
Location: Spencer IN
Contact:

Re: Trim

Post by Bo Grave »

Hi,

My 7BCM with a C85-8 Stroker. will trim to 55 but i'm about 260lbs also with passenger don't need to use the trim much. I would also recommend you check the rigging of your trim tab.

Eugene (Bo)
N1663E
Eugene ( Bo ) Grave
A&P, IA, R&E
CHAMP
CHIEF
BONANZA

MikeB
Posts: 3255
Joined: Wed Nov 17, 2004 17:07
Location: Western Wisconsin
Contact:

Re: Trim

Post by MikeB »

It does seem like all the Champs I've flown have been a bit nose heavy. My 65 horse 7AC trimmed out better than my L16 with the starter and 0200 engine. The "L" is pretty much forward CG even with a 25# battery behind the rear seat and I'm a light guy at the about 160#. Both had the trims set to specs. No problem trimming to 55-60 with a rear seat passenger, though. I think it's just the 'nature of the beast' and just keeps you on your toes on approach. If I'm a little fast at touch down the 'no bounce' covers up my sins :oops: .

Mike

7ECjim
Posts: 84
Joined: Mon Mar 27, 2006 22:27
Location: North West
Contact:

Re: Trim

Post by 7ECjim »

Slowing to 55 should not be a problem for the champ when they are flying at a slow pace of 80-85.
I never touched the trim. Set it neutral at take off and it stayed there. 850# empty 0-200 with stock engine mount, y pipe exhaust,light weight starter only,bendix mags,gill 25 behind the rear seat,scott 2000 TW. Very well balanced set up and very light on the stick no need to trim. You could set the trim if you wanted but it was not needed. If you are having a heavy stick I would look into changing things around to balance it out.

MikeB
Posts: 3255
Joined: Wed Nov 17, 2004 17:07
Location: Western Wisconsin
Contact:

Re: Trim

Post by MikeB »

I'm heavier at about 950# which might be part of the problem but I'd say most of the weight is over the CG. Metal prop and mufflers also add to the nose heavy condition and of course, the 13 gallon nose tank. As I previously posted it seems those with the 13 gallon wing tanks and nose tank seem to 'balance out' better. I can't think of anything else that I haven't mentioned that would add to the forward CG. Having said that it's not a real problem just takes a bit more concentration.

Mike

CF-KYE
Posts: 44
Joined: Sat Sep 17, 2005 09:43
Location: Lacombe, Alberta, Canada
Contact:

Re: Trim

Post by CF-KYE »

I did a little experimenting tonight with my 7CCM (converted to a 7EC, more or less). I flew it for the first time yesterday in better than a year, did one circuit and wasn't certain that I had the tailwheel on the ground when I three pointed it. In the past I'd always landed it with a little bit of power on, mostly just playing and keeping the engine warm, and usually three pointing it , but tonight I did three power off three-point landings and not only do I run out of trim but at just below 60 mph I run out of elevator! I'm certain that the rigging is wrong and am going to check that very carefully next weekend. I'm also maybe a touch heavier than I was last year - maybe 265 lbs. But the pilot's seat has a positive arm of around 11". I was also fairly light on fuel (no nose tank, two wing tanks, 39 USG total). My question is this though: will a Champ trim out properly for a little pilot but not for a "pork chop" like me? I know she used to when I was a kid, but that was a whole rebuild ago.

Dan

User avatar
hangerash
Posts: 654
Joined: Fri Nov 02, 2012 06:12
Location: Montezuma, OH (CQA)
Contact:

Re: Trim

Post by hangerash »

Dan,

Good question. I have a 7CCM I just recovered and there was 8 lbs of lead at the tail post. I also have a Scott 3200 tail wheel. The AP/IA I am working with said he didn't think I would need the 8 lbs with the Scott tail wheel, yet I continue to follow these discussions about running out of elevator trim. I'm anxious to read the replies to your question.

Richard in OH
Richard

Paul Agaliotis
Posts: 2554
Joined: Wed Dec 08, 2004 18:49
Location: San Martin, California
Contact:

Re: Trim

Post by Paul Agaliotis »

These little planes will get nose heavy real quick. Everyone wants a starter, radio stack and an aluminum prop. All of this stuff heavy and most of it is forward of the datum. If you don't want to reduce the equipment you need to add weight to the tail or a tab on the right elevator.
Paul
Mailing Adress : Paul Agaliotis 2060 E. San Martin, San Martin,Calif. 95046

Holcombe
Posts: 196
Joined: Thu Oct 16, 2008 20:28
Location: Florence, Oregom
Contact:

Re: Trim

Post by Holcombe »

My 7-CCM solo won't trim below about 65/70 mph. Got used to it.
With a passenger I can trim much slower, but then I get that tail sinking feeling. Never get used to that.
Tail winds are a "Good Thing"

User avatar
rkittine
Posts: 912
Joined: Mon Sep 13, 2010 13:48
Contact:

Re: Trim

Post by rkittine »

Full aft trim in my 7CCM takes a LITTLE back pressure off how much you need to hold when landing. When I have new tailwheel student though I impress upon them the inadequacy of the trim even with me in the back seat and I make sure they do at least one lesson with the trim set full aft for the full time and then one with it set full forward. Breaks them from over relying on trim!
Robert P. Kittine, Jr.WA2YDV
West Nyack Aviation, L.L.C.
New York, New York 631-374-9652
rkittine@aol.com

vintageair
Posts: 47
Joined: Wed Aug 05, 2009 14:56
Contact:

Re: Trim

Post by vintageair »

A feature of a servo tab elevator trim that many people are not aware of is that as you trim full nose up you are also reducing the effective elevator surface which then reduces the maximum elevator authority. This is why, if you have pushed the trim all the way back you may run out of elevator in the flair.

Post Reply