Pitch trim tab actuation. Thoughts?

[Freemasm]

Not sure where this questions goes but,

Built an RV4 emp per (old) plans. No mentor or builders at my airport. The trim tab is intended to be actuated "remotely" vs having the actuator installed in the elevator like newer models. So now my conundrum.

I have to reskin the elevators anyway and have the kit for the later installation plan. What are the pros/cons to the different ways to actuate/placement of the actuators? I assume Vans changed it for a reason. Your help and thoughts would be appreciated.

Edit = For an F4, four cylinder Rocket. Not an RV4

 

[Ironflight]

On our RV-3, we created a short Bowden cable, mounted the servo on the deck under the vertical stab, and ran the Bowden cable out to the tab - lightweight, compact, doesn’t mess up the elevator balance….. and far easier to connect and maintain the servo if you have to work on it.

 

[Mel]

On our RV-3, we created a short Bowden cable, mounted the servo on the deck under the vertical stab, and ran the Bowden cable out to the tab - lightweight, compact, doesn’t mess up the elevator balance….. and far easier to connect and maintain the servo if you have to work on it.

Agree with Paul. I like this method better than having the servo in the elevator.

 

[fixnflyguy]

I have the "per plans" actuator in the elevator. I bought my tail kit unfinished and it had the manual trim cut-outs already done, but I simply modified the shape of the mounting plate. The servo is actually attached to a removable skin piece. I think its simple, and elegant, removes easy for maintenance. I made my own style control horn that's part of the close-out rib on the tab. I ran a bundle ( In the sheath I plan to send you) of the wires to the control stick and have my trim for elevator and ailerons on the stick. the servo is well forward and affects the balancing minimally. If I had an original manual trim that I converted to electric, I would probably have done the short teleflex and servo under the fairing.

 

[Little Al]

Not sure where this questions goes but,

Built an RV4 emp per (old) plans. No mentor or builders at my airport. The trim tab is intended to be actuated "remotely" vs having the actuator installed in the elevator like newer models. So now my conundrum.

I have to reskin the elevators anyway and have the kit for the later installation plan. What are the pros/cons to the different ways to actuate/placement of the actuators? I assume Vans changed it for a reason. Your help and thoughts would be appreciated.

Edit = For an F4, four cylinder Rocket. Not an RV4

For a Rocket. Not trim motor related but trim tab related. I would consider modification to the trim tab actuator arm. The three little pop rivets that hold that arm on need some upgrading. I know of at least one Rocket that had one pull loose in flight. By the grace of God the Amazing pilot got it back on the ground safe. The Elevator got peeled open like a tuna can as a result.

 

[fixnflyguy]

For a Rocket. Not trim motor related but trim tab related. I would consider modification to the trim tab actuator arm. The three little pop rivets that hold that arm on need some upgrading. I know of at least one Rocket that had one pull loose in flight. By the grace of God the Amazing pilot got it back on the ground safe. The Elevator got peeled open like a tuna can as a result.

Take a look at my pic in my above post. On my RV-4, I riveted my DIY arm to the tab end rib with 5 Cherrymax rivets. Its robust and isn't going anywhere.