What's new
Van's Air Force

Don't miss anything! Register now for full access to the definitive RV support community.

Electric trim? Thrashed through old threads yet questions remain.

J

jj_jetmech

Well Known Member
With Dynon skyview / 2 axes auto pilot, well for this matter any other AP brand used in an RV, what capability will be lost with manual trim? Any? Sounds like the electric trim sensitivity , if a problem can be fixed... So how many trim run aways or stop failures have there been? I like the idea of a secondary switch maybe on the panel in addition to the yoke hat switches.... (I was working on my friends 4 recently he has E flaps on yoke hat switches and flaps were intermittent due to one of the yoke switches being gunked up.... Probably from his ham fisted kung foo death grip,,,, Don!) Anyway I see that as a week link...... One could wire the panel switch to have priority... That would resolve that and provide switch redundancy... Thinking manual aile trim and elec. elev trim.... Love the idea of just a thumb bump to neutral trim....
Please comment further... Thanks!
 
I have Dynon SkyView and 2-axis autopilot and manual trim. No capability is lost with manual trim. The autopilot does not work through the trim system but a separate servo. I have an autopilot disconnect switch on the panel plus toggle switches on the power supply to each of the autopilot servos so if one runs away I can hit the disconnect switch and if that fails I can flip the toggle switches and cut off power.

SkyView lets me know when I need to trim up/down a little while on autopilot. Great system. Perhaps some systems include auto-trim but to the best of my knowledge SkyView does not, although I don't think that is any big deal.

I don't see any need for aileron trim of any kind. If the plane is built straight and control surfaces adjusted right it should fly pretty straight except for fuel burn. If you have roll autopilot then I really don't see a need for aileron trim. I flew my -8 for about 370 hours without any autopilot and a lot of that was long trips. It really did not take much to keep it headed in the right direction.

You don't say if you are building a side-by-side model or tandem like an -8 or a -4. I have an -8 and the one reason I wish I had electric elevator trim is for the back seater to be able to trim the elevator if I became incapacitated. That and a throttle in the back seat would give them a chance.
 
Bubblehead said:
I have Dynon SkyView and 2-axis autopilot and manual trim. No capability is lost with manual trim. The autopilot does not work through the trim system but a separate servo. I have an autopilot disconnect switch on the panel plus toggle switches on the power supply to each of the autopilot servos so if one runs away I can hit the disconnect switch and if that fails I can flip the toggle switches and cut off power.

SkyView lets me know when I need to trim up/down a little while on autopilot. Great system. Perhaps some systems include auto-trim but to the best of my knowledge SkyView does not, although I don't think that is any big deal.

I don't see any need for aileron trim of any kind. If the plane is built straight and control surfaces adjusted right it should fly pretty straight except for fuel burn. If you have roll autopilot then I really don't see a need for aileron trim. I flew my -8 for about 370 hours without any autopilot and a lot of that was long trips. It really did not take much to keep it headed in the right direction.

You don't say if you are building a side-by-side model or tandem like an -8 or a -4. I have an -8 and the one reason I wish I had electric elevator trim is for the back seater to be able to trim the elevator if I became incapacitated. That and a throttle in the back seat would give them a chance.
Click to expand...

My "ex" 6 is a side by side. I installed the Van's aileron trim, that uses the small servo operated tab. I just don't like "bias springs". Being a side by side, I like the perfect trim, that can be done with the tab. This way, an auto-pilot isn't engaged to level the wings. Mine was electric, with a four way hat switch on the stick for pitch & roll. Very convienient. I'd also get comments on how well the plane trimmed. No speed controllers either.
 
Bubblehead said:
I have Dynon SkyView and 2-axis autopilot and manual trim. No capability is lost with manual trim. The autopilot does not work through the trim system but a separate servo. I have an autopilot disconnect switch on the panel plus toggle switches on the power supply to each of the autopilot servos so if one runs away I can hit the disconnect switch and if that fails I can flip the toggle switches and cut off power.

SkyView lets me know when I need to trim up/down a little while on autopilot. Great system. Perhaps some systems include auto-trim but to the best of my knowledge SkyView does not, although I don't think that is any big deal.

I don't see any need for aileron trim of any kind. If the plane is built straight and control surfaces adjusted right it should fly pretty straight except for fuel burn. If you have roll autopilot then I really don't see a need for aileron trim. I flew my -8 for about 370 hours without any autopilot and a lot of that was long trips. It really did not take much to keep it headed in the right direction.

You don't say if you are building a side-by-side model or tandem like an -8 or a -4. I have an -8 and the one reason I wish I had electric elevator trim is for the back seater to be able to trim the elevator if I became incapacitated. That and a throttle in the back seat would give them a chance.
Click to expand...

Building a 7 .....
 
TCW Safety Trim

jj_jetmech said:
With Dynon skyview / 2 axes auto pilot, well for this matter any other AP brand used in an RV, what capability will be lost with manual trim? Any? Sounds like the electric trim sensitivity , if a problem can be fixed... So how many trim run aways or stop failures have there been? I like the idea of a secondary switch maybe on the panel in addition to the yoke hat switches.... (I was working on my friends 4 recently he has E flaps on yoke hat switches and flaps were intermittent due to one of the yoke switches being gunked up.... Probably from his ham fisted kung foo death grip,,,, Don!) Anyway I see that as a week link...... One could wire the panel switch to have priority... That would resolve that and provide switch redundancy... Thinking manual aile trim and elec. elev trim.... Love the idea of just a thumb bump to neutral trim....
Please comment further... Thanks!
Click to expand...

Installed this and never looked back:
http://www.tcwtech.com/Safety-Trim%20Page.htm
Never had to adjust it. It just works. I'd do it again...check it out.
 
Bubblehead said:
I have Dynon SkyView and 2-axis autopilot and manual trim. No capability is lost with manual trim. ...
Click to expand...
Ditto!

When I was building my goal was build a light, simple, and safe airplane.

Thus I have the manual trim for both pitch and roll. (L.Adamson's comments regarding the springs if for roll only, not pitch.)

I find nothing objectionable in the manual roll or pitch trim. About the only drawback to the manual trim is the cable just about fills up one of the limited number of pass throughs to the tail section.

Other than that minor nit, I am very happy with the manual trim.
 
You must log in or register to reply here.
Back
Top