Van's Air Force
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MAC / Ray Allen Servos
- Thread starter rv8or
- Start date
HFS
Well Known Member
From The "Wayback" Machine ...
If, for some reason, you have a "mature" avionics package (nee - sans electronic "marvels") you can wire the servo to two parallel circuits.
In cruise, you would like to slow down the servo speed so as not to "overshoot" trim tab movement each time you "blip" the switch.
In the pattern, you would like to have the trim "reaction" be as quick as the servo 's op speed.
In simpler terms - the faster you are going (cruise), the slower you would like the trim input reaction to be; and, the slower you are going (pattern/landing) the faster you would like to input reaction to be.
The circuit for "cruise" is wired through a speed controller, so that op speed can be controlled to your liking.
The circuit for "pattern/landing" is wired (at full speed) through a micro switch activated by the initiation of flap movement.
Two parallel circuits for a mechanical solution - simple, but (very) basic compared to the electronic options available to new builds now.
YMMV - but this has worked for me for more than 20 + years.
HFS
HRII S/N 002
If, for some reason, you have a "mature" avionics package (nee - sans electronic "marvels") you can wire the servo to two parallel circuits.
In cruise, you would like to slow down the servo speed so as not to "overshoot" trim tab movement each time you "blip" the switch.
In the pattern, you would like to have the trim "reaction" be as quick as the servo 's op speed.
In simpler terms - the faster you are going (cruise), the slower you would like the trim input reaction to be; and, the slower you are going (pattern/landing) the faster you would like to input reaction to be.
The circuit for "cruise" is wired through a speed controller, so that op speed can be controlled to your liking.
The circuit for "pattern/landing" is wired (at full speed) through a micro switch activated by the initiation of flap movement.
Two parallel circuits for a mechanical solution - simple, but (very) basic compared to the electronic options available to new builds now.
YMMV - but this has worked for me for more than 20 + years.
HFS
HRII S/N 002
Mike S
Senior Curmudgeon
I installed one of these in the RV 10.
https://www.tcwtech.com/product/safety-trim-intelligent-servo-controller/
I used one of these in the new plane.
In both cases, well worth the time and cost to install.
http://www.matronics.com/governor/index.htm
https://www.tcwtech.com/product/safety-trim-intelligent-servo-controller/
I used one of these in the new plane.
In both cases, well worth the time and cost to install.
http://www.matronics.com/governor/index.htm
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We’ve got a couple of airplanes with controllers that select “high” or “low” for trim speed, and a couple that don’t. Having built my RV-8 back twenty years ago, it has just one speed, and I’ve never felt I needed anything else. Our RV-6 had one speed, and it was a bear to get it trimmed out perfectly at cruise - until we installed a two-speed controller. But…. When I fly it these days, I am pretty much engaging the autopilot in cruise and letting it deal with a slightly out of trim condition if it must….so I rarely remember to set trim speed switch in flight - I just use what’s there. The RV-3 has one speed, and it is to slow….but since it is using full voltage, there’s no way to speed it up without changing servos or the mechanical advantage setup.
Bottom line - it works OK either way, and you’ll get used to what you have…. Probably …
Bottom line - it works OK either way, and you’ll get used to what you have…. Probably …
RV8JD
Well Known Member
My two RV-8s do not have trim speed controllers and that works fine. It's fairly easy to get a good pitch trim even in cruise. Sometimes it's necessary to 'blip' the pitch trim coolie hat switch on the stick to get perfect pitch trim, but I've never found it objectionable.
Having a trim speed controller might be a convenience, but not necessary in the -8.
YMMV of course!
Having a trim speed controller might be a convenience, but not necessary in the -8.
YMMV of course!
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Trim speed
Thanks for the replies, I was a little unsure wether it was worth running it through the G3X, I like to keep things simple.
My RV3’s trim mirrors yours Paul and I have seen that pitch trim in RV6’s need fine adjustment. Reason for the question was that I have no experience of flying RV8’s.
Happy RV filled New Year
Best regards and thanks,
Rob
Thanks for the replies, I was a little unsure wether it was worth running it through the G3X, I like to keep things simple.
My RV3’s trim mirrors yours Paul and I have seen that pitch trim in RV6’s need fine adjustment. Reason for the question was that I have no experience of flying RV8’s.
Happy RV filled New Year
Best regards and thanks,
Rob
