Lucky Dog

My Feedback: (1)

Exactly. On a split elevator, it's easy to set-up. A full flying elevator (like on a scale Eindecker), a bit more of a challenge.

abufletcher

You're right that I hadn't thought of mounting dual elevators up front (with dual cable systems). That could, indeed, be a handy solution on some WWI models, for example, on types that had an external control horn in the front, like the DH1a.

abufletcher

Stegl, it's also interesting to see your servos mounted in the stab halves themselves. Never seen that before. I suppose on most models adding weight in that location makes that impractical.

abufletcher

Not least of which because you'd have to cut the central "spar" in half so that each half could rotating independently. I have to admit that idea raises my scale hackles.

thailazer

I put dual elevator servos in my Super Scout. Just used a Y harness on them and used the opposite side of a control horn on one side. Only thing you have to watch out for is that the angle of the control linkage rod is such that the travel will be the same on both sides, although I doubt a mm of difference would be cause for concern. Keep it simple!

radfordc

My Feedback: (14)

Here is a way to have the redundancy of dual servos while driving only one link to the tail.

rcguy59

My Feedback: (8)

Reminds me of the old mechanical v-tail and elevon mixers.

stegl

By using the right servo with low weight this is very practical. The cost was higher but by running each servo wire into a separate receiver port kinda makes for a bit of redundancy in case one should pack it in. Not that I was concerned in that area as the servos used are pretty high quality. Application outweighs the cost for me.
The took the weight of the added weight in the tail and subtracted the weight of a metal cross link and a pushrod and added weight was not a whole lot more...

Lucky Dog

My Feedback: (1)

I may be wrong, but if one servo stalls, it's not going to help correct?

radfordc

My Feedback: (14)

Depends on where the failed servo stops. If it stops a center the other servo will provide about 1/2 the normal control movement. If it stops at the end of its travel the other servo can only counteract the problem by maintaining the control surface in it's neutral position.

stegl

I guess we could put it this way..... if using only one servo you are totally hooped; if using two independent servos you may only be half hooped or you may have a chance that survival may work and if we look at all the negatives then better to hang up our hobby and spend all our time on the internet with all our what-if's ....

Boomerang1

And, that's what counts!

Servos rarely fail anyway but when I had an aileron servo fail on a dual servo setup it was enough to save the model.
It took full opposite aileron on the good servo to maintain control & get the model safely down.

Radfordc's linkage method results in reduced movement evenly to both elevators. One drawback of dual servo to elevator
halves is unwanted roll when one fails, not too big a problem with many models but a real problem on some. - John.

wattsup

My Feedback: (1)

Just thought I would get someone to help me with setting up 4 aileron servos on a biplane. I do not want to use Y's. I am using an Airtronics SD-10G transmitter. I tried to use the "Procedure to obtain DUAL AILERONS in each wing of a BIPLANE" originally written by Jack R Albrecht, Airtronics Technical Su[pport and revised on 29 June 2010. Everything Jack wrote about this procedure worked up to the point of activating the Snap Roll Function. At that point, only the lower wing aileron servos worked while performing a snap roll. I have tried just about everything I know to do to get ALL 4 wing servos to activate in the performance of a snap roll and so far have not been successful. Failing to get helpful information, my next step will be to use 2 Smart-Fly Equalizer II units. Any suggestions would be appreciated. Thanks in advance.