310 trim indicator and throttle

Topper

Topper

Pre-takeoff checklist
Joined
Nov 18, 2012
Messages
416
Location
Benton
Display Name
Display name:
Topper
I have a new to us 1956 310a. During the first annual they replaced the trim wheel on the side of the throttle quadrant. The back (or inside) of the trim wheel is like a record and as the trim is adjusted, the indicator rides in the groove and indicates the position of the trim tab. When flying the other day, the indicator got all out of whack and I could not get the trim tab to move level or below the elevator. The shop loosened the trim wheel and repositioned the indicator. They thought that I must have hit it or my instructor did when pulling power. Flew it today and we were very careful to not hit the indicator. I got out of whack again. Any ideas what may be causing this.

The other problem (at least annoyance) it the throttles. The right engine is more sensitive than the right. Let me give an example. Assume I keep both levers right next to each other and advance throttle. If the right engine is at 2000 rpm, the left engine will be at about 1500. Now if I pull them both back, still next to each other until the left engine is at 1200, the right engine will be at 1000 rpm. I think I will get used to it, but it would be nice to fix. It is like moving the levers the same amount, moves the right engine more than the left.

I do plan to measure the distance that moving the levers moves the throttle body to make sure that it is something with the linkage and not the throttle body.

FYI, this plane has had the engines replaced with fuel injected engines.

Thanks,

Jim
 
Topper said:
I have a new to us 1956 310a. During the first annual they replaced the trim wheel on the side of the throttle quadrant. The back (or inside) of the trim wheel is like a record and as the trim is adjusted, the indicator rides in the groove and indicates the position of the trim tab. When flying the other day, the indicator got all out of whack and I could not get the trim tab to move level or below the elevator. The shop loosened the trim wheel and repositioned the indicator. They thought that I must have hit it or my instructor did when pulling power. Flew it today and we were very careful to not hit the indicator. I got out of whack again. Any ideas what may be causing this.

The other problem (at least annoyance) it the throttles. The right engine is more sensitive than the right. Let me give an example. Assume I keep both levers right next to each other and advance throttle. If the right engine is at 2000 rpm, the left engine will be at about 1500. Now if I pull them both back, still next to each other until the left engine is at 1200, the right engine will be at 1000 rpm. I think I will get used to it, but it would be nice to fix. It is like moving the levers the same amount, moves the right engine more than the left.

I do plan to measure the distance that moving the levers moves the throttle body to make sure that it is something with the linkage and not the throttle body.

FYI, this plane has had the engines replaced with fuel injected engines.

Thanks,

Jim
Click to expand...

Find a mechanic that knows how to work on these. It's in the Maintenance Manual how to rig the engine controls, takes time but is worth it.
 
Topper said:
I have a new to us 1956 310a. During the first annual they replaced the trim wheel on the side of the throttle quadrant. The back (or inside) of the trim wheel is like a record and as the trim is adjusted, the indicator rides in the groove and indicates the position of the trim tab. When flying the other day, the indicator got all out of whack and I could not get the trim tab to move level or below the elevator. The shop loosened the trim wheel and repositioned the indicator. They thought that I must have hit it or my instructor did when pulling power. Flew it today and we were very careful to not hit the indicator. I got out of whack again. Any ideas what may be causing this.

The other problem (at least annoyance) it the throttles. The right engine is more sensitive than the right. Let me give an example. Assume I keep both levers right next to each other and advance throttle. If the right engine is at 2000 rpm, the left engine will be at about 1500. Now if I pull them both back, still next to each other until the left engine is at 1200, the right engine will be at 1000 rpm. I think I will get used to it, but it would be nice to fix. It is like moving the levers the same amount, moves the right engine more than the left.

I do plan to measure the distance that moving the levers moves the throttle body to make sure that it is something with the linkage and not the throttle body.

FYI, this plane has had the engines replaced with fuel injected engines.

Thanks,

Jim
Click to expand...

There are two possibilities with the the throttle, and the likelihood is that it's some of both. First is the physical rigging of the throttle cables. It's kind of a PITA, but straight forward and pretty simple. The second is the injector pump pressure setting. This is another somewhat involved procedure that takes a secondary measuring probe plugged into the system for accurate pressure monitoring. To get both of the systems correct figure a day's shop labor.

It is worth it to have everything correct and the handles evened up (even if you do advance the left one first) as you now have an early indicator of things not being right with an engine when things are split.
 
Thanks for the responses.

Jim
 
FYI, I figured out the trim indicator problem. My right knee hits the bottom of the trim wheel enough to flex the top out to allow the indicator to fall out of position. Seems like there should be a block of something behind the wheel to keep this from happening. Maybe once I get the instructor out of the plane and not pulling power on hype left engine the problem will disappear.
 
How is your seat positioned that your knee is displacing the trim wheel that bad?
 
The seat position is good in relation to the pedals, yoke, etc. it must be a comfort thing for me to put some pressure with my right knee. Flew the 182 today and did not put pressure on anything with my knee. I bet if I could fly without the instructor always pullin power, I wouldn't have the problem. Fly the 310 tomorrow, will see if I can keep my leg off. BTW it does not take much pressure, I can push it with one finger hard enough for the indicator to slip.

Jim
 
Topper said:
The seat position is good in relation to the pedals, yoke, etc. it must be a comfort thing for me to put some pressure with my right knee. Flew the 182 today and did not put pressure on anything with my knee. I bet if I could fly without the instructor always pullin power, I wouldn't have the problem. Fly the 310 tomorrow, will see if I can keep my leg off. BTW it does not take much pressure, I can push it with one finger hard enough for the indicator to slip.

Jim
Click to expand...

It doesn't sound like the trim mechanism/mounting is in proper condition, mine was quite sturdy and my hand rests on the trim unless it needs to be elsewhere. I never noticed any flexibility or had the indicator pin skip the groove in the wheel.
 
You must log in or register to reply here.
Back
Top