Timthetoolman1

My Feedback: (6)

Has anyone lost a warbird that had dual digital metal gear servos on the elevator, one on each half, from a failure of one of these servos?

I know there are a lot of people out there against it but I want to know if there is any validity. I want to hear from someone that has used the system and experienced a failure.

Tim

giddyuperic

Did you use a servo reverser? Or put each servo on it own channel?

STUKA BARRY

I do this all the time. I either use a Y extention (old school) or dual receivers. I cant answer your failure question, as knock on balsa, I've never had a failure. Only speculation here, but if a servo does fail, the wind should allow the flight control to neutralize and allow for the other half to get you on the ground. If the servo locks up in an up or down deflection, some over compensation with the ailerons should get you on the ground. You do this with the ailerons, it should be the same principal, granted if an aileron locks up, your in deep kimshi, again only speculation on my part.

Gremlin Castle

My Feedback: (14)

Just experienced a failure of an aileron servo at the Rally of Giants this past week. Metal gears are fine but something in the electronic/electrical components went south. Fortunately it showed up during the preflight but had to have happened sometime during the previous flight.
That being said, I have lost very few full size servos in the last 40 years. I did go through a bunch of minature servos trying to use them as throttle servos but that was me being dumb trying to save an insignificant amount of weight.

Texastbird

I had one of the elevator servos quit on me just last week. I was able to nurse it around the pattern and set up a pretty good landing. If I had been running one servo, it would have been curtains for sure. I have several planes set up with dual elevators and this is the first time I had any kind of problem.

Boomerang1

Standard practice for me on big models. One thing to watch for is not having the elevator halves linked together by a cross bar. This can lead to each servo fighting each other to establish the required control deflection. This can, I have heard, be avoided by adjusting the deadband on programmable servos. - John.

beepee

Not a war-bird, but I have saved an airplane with a lost servo on a dual elevator arrangement. It was the linkage that failed. I noted major loss of elev authority and brought it in. Nice to have such a failure and still have an airplane afterwards!

Bedford

Firebar

My Feedback: (3)

A few years ago I had a Midwest Extra 300 with two metal gear elevator servos. The plane was over powered with a G-62 on it. At the bottom of a loop something flew off of the plane. I throttled back and made an un-eventful landing. As I taxied back I saw that half of the elevator was gone. Having separate elevator controls saved the plane.

Another experience that might help someone...
I was flying the same plane a few months later. I used a short Y connector from the receiver to the wing extension wires and had both ailerons on the same channel. I plugged in the wing servos, pre-flighted the plane, checked the controls and took off. After a few minutes the plane went erratic. I would have control one moment and then lose it then get it back again. After the plane crashed I found that one of the three wires in the aileron Y connector had pushed back into the connector. When it made contact everything was normal when it vibrated open the aileron channel would jam the ailerons full one way. I now use separate channels for each aileron and each elevator half.

Charlie

CLBAKER

I HAD an Extra 300 1/4 scale with two 645 HiTec servos and had one fail pulling out of a Cuba 8. The servo that failed was locked in an up position so when I slowed the plane down she snapped and went in hard. I also found a gear tooth missing in the other servo. It was a bad day for servos.

wind junkie

My Feedback: (1)

I'm not sure what you're asking. If you only had one servo for both elevator halves, and it failed, you'd obviously lose the plane. Having two of them gives you a fighting chance to bring the plane back even if one failed at an extreme position.

Connecting the servos with redundant wire harnesses gives the least chance for failure (due to unplugging). You have to inspect and judge your installation yourself to see how likely it would be for something to come loose, fray, get caught in a linkage or other moving part, etc.

I've landed planes with one aileron a few times. Mostly due to mechanical failure due to flutter or bad linkages.