daveopam

My Feedback: (9)

"Are you sure it's not rf coming down the metal pushrod? Are you on 2.4
A nyrod will stop vibrations as well so I would use that."

Never really thought about RF noise. The ball link ends are plastic and the pushrod does not touch anything metal. It may touch the firewall under vibration but that's all. I also assumed it wasn't RF noise since it only effected one servo. For some reason I thought RF noise caused interference in the RX and would effect all the servos. In my case all the other servos function normally. This is a 2.4 FASST RX. The throttle servo is close to the LiPo RX battery but not close to the NiCad IGN battery. I may push my luck a little and change to Nyrod before changing the servo. (not advising anyone else to do the same) This should tell me if it is vibration or RF noise. If I still have issues than I would assume the servo is bad from being vibrated. If this cures the problem then it's most likely it was RF noise.

David

Bob Pastorello

My Feedback: (198)

David - do you have an electronic kill switch on board? If so, how close is it to that servo?

BTW - love your signature line....great RC perspective, too!

thepamster

I don't understand why some here are talking about rf interference damaging a servo. Interfere yes, damage no. At least not electronically.
How about that servo operating off of Lipo power and burning it out due to high voltage. You didn't describe the rest of your setup as in regs, power boxes or the like.
Just wondering.

thepamster

I reread his original post again and had forgot about the blipping of the servo. Though that sounds like interference I don't think that would damage it unless it stalled it out and broke some gears.
Still curious about high voltage to a S3004. I operate them at 6.6v ok but 7.4.....

kerwin50

Better put that spring back on the throttle arm. With out that spring it will wear out that carb where the shaft goes through the carb.
For throttle servos on my gassers I've been using the solar D770's. They work very well and center very well. If a throttle servo does not center well it's hard to get a the same rpm at an Idle.
I personally like metal gears on gasser throttles as I have a couple of failures over the years. But then again I've been flying since the wright brothers. LOL

hsukaria

Great point!!! The servos have to be high voltage rated if you are going over 6 volts (6.x). So, I would look there first. If the OP is running 7.4V and all his radio is set up for high voltage except the throttle servo, that is where it will fail. The Rx can handle the higher voltage, but the servos are the limiting factor.

Bob Pastorello

My Feedback: (198)

I missed that part in the OP....and agree...that spring holds the butterfly centered in the venturi, and prevents it wearing grooves/gaps in the venturi and on the butterfly. Un-hooking the spring from the return arm is done frequently, but I don't think very many experienced guys remove the spring, except maybe the first time before they found out how come that's a bad idea. Erratic running, poor idle, inconsistent throttle all can occur within a short time of having that spring totally removed.

If anyone wants a "war story" about how I learned it, let me know, although it isn't very exciting.

daveopam

My Feedback: (9)

Bob, I do not have a kill switch at all. Yes I know it's a good idea but was talked out of it by the owner of the LHS. I will hook the return spring back up while I have the cowl off.

Pam, I have a Flight Power reg on this plane. I have it adjusted to 6V. Was a good thought though, thanks.

david

kerwin50

Have you tried operating your throttle with out the servo? Is it fairly easy with no binding?
I once went through a couple of rudder servos due to excess drag.

Bob Pastorello

My Feedback: (198)

So you did not "remove" the spring from the shaft, you just "unhooked" it from the return arm? If so, that is very common practice, although some debate whether needed or not, I don't like to full-time load the servo by leaving it hooked onto the return arm. Frankly, cannot imagine a LHS talking anyone out of an on-board engine kill mechanism, whether electrical or mechanical, but it isn't "required" yet by anyone other than IMAA and then only for events. Psychologically, I like knowing I can stop that thing if something goes amiss in flight. Seeing a 100cc powered aerobat get "stuck" at nearly full throttle once was all I needed to ever become a believer in it.

drac1

My Feedback: (4)

JR DS362 on my glow engines with a 1/32" piano wire push rod inside a nylon tube. Dubro 1/16" nylon ball link (snap on) on the throttle arm.

JR DS8231 on my 33% Edge 540, DA100. Hangar 9 Pro Link for pushrod with Dubro ball links (nylon outer with brass ball) on each end.

Li Ions with no reg.

Never had any issues with these set ups.

3136

If you keep it above the strip in a safe dead stick landing area that would be a great test.

PS you already know this, but test with lots of height.

mike31

My Feedback: (67)

HS-81. Not a lot of force required to move a throttle arm!

daveopam

My Feedback: (9)

Bob you know the man that said I did not need a kill switch. His place is on North May. He said it was just something else that could go wrong. Not bad mouthing him it all. He has been a lot of help to me over the last 20+ years. But he did talk me out of it on my first gasser.

Yes the spring is just unhooked not removed for the throttle arm. Like you I could not see the plus side to having a load on the servo at all times. If it helps center the shaft than so be it. Not much of a load anyway.

David

Bob Pastorello

My Feedback: (198)

there is no icon for speechless

kmeyers

Like I said I have had the same problem twice.

Once it was the ignition module itself. replaced the module problem solved. again the servo thought to be bad tested good.

Second time it was the power wiring touching the throttle linkage ( all plastic nyrod) changing the wiring a couple of inches fixed the problem.

If you had a switch on your ignition power wire it would be a very simple test to try the servo with the ignition off.

Mly vote is servos are still good and you are getting RF noise.

daveopam

My Feedback: (9)

Thanks, Got the day off Tuesday and going to work on it. Don't know when I will get the OKLA wind to lay down for a test flight.

david

av8tor1977

My Feedback: (6)

I once flew an ultralight airplane with an ultralight dealer in northern Oklahoma. Wind was about 20 gusting to 30. He said "We don't know how to fly when the wind doesn't blow here."

AV8TOR

daveopam

My Feedback: (9)

That's true av8tor. We have a 45'x500' runway at our site. When it's calm we roll off the end of the runway on landing

duber3

Yep they are gaz powered plane, the corsair have a Evolution 58GX2 and the mustang have an DA50, the Corsair is 8 years old, still the same servo for the throttle
It's not only for the throttle, thay are in both plane for the ailerons

duber3

If I remember right, the problem with the DS821, was that people had put Loctite on the screw, really bad idea!!!!, I'm sure that I can still find the bulletin from horizon, sure horizon recommend 60-90 planes but a warbird have little ailerons, so the DS821 is plenty strong for a warbird
as for vibration, my corsair and mustang don't that much compare to my little H9 mustang with a saito 100 in it

3136

Hi Dave, just curious, did you fix it?

dirtybird

My Feedback: (5)

I think your problem is simple. You had two bad servos.

daveopam

My Feedback: (9)

I have worked it guys, but the Oklahoma weather has been unkind this year. I have been getting my one flight a month to maintain my all season flyer. But didn't think it was a great idea to fly one that might dead stick on a windy day.

Davif

Bob Pastorello

My Feedback: (198)

"OK wx has been un-kind" - what a diplomat!!!!
I'm not one to complain - usually - but this winter/spring has had nothing flyable by my standards AT ALL !!!
But - looks like next week we jump into summer scorched-earth heat, so that means the summer High will sustain the terrible winds we've had so far.
It's gotta break sometime....