Engine Interference
 

Hi,
I have just bought a Super Tiger GS-45 ABC engine and it is interfering with my radio. I have a trainer plane that I took the engine out of to put in another plane. I am replacing that engine with this Super Tiger so I can use both planes. The radio and receiver are the same ones that were always in the trainer plane and never have a problem. The receiver works fine with the engine is off, there is no servo twitching. When you start the engine the servos go crazy, making the plane uncontrollable. The servos will move about half of their range of movement back & forth. If you shut the engine down the receiver is fine again (no interference). This never happened before with the other engine. Can anyone help me with this problem?
Thanks, Matt

RE: Engine Interference
 

That sounds like a vibration problem. Some engines are worse than others. Did you balance the prop. Is there plenty of foam around the reciever?

RE: Engine Interference
 

That sounds like a vibration problem. Some engines are worse than others. Did you balance the prop. Is there plenty of foam around the reciever? Also be sure there is no metal to metal in your throttle linkage.

RE: Engine Interference
 

I only have foam mounting tape under the receiver, I will put some foam under it. I will also check to see if the prop is still balance, I did it when I put it on but the prop is known to scuff the ground ever so often

RE: Engine Interference
 

A Super Tigre .45 is an excellent & powerful engine. There is no way it should cause radio interference unless you have some problem in the receiver. I would have your receiver checked for vibration.

I would also make sure there is no metal-to-metal connection that can be vibrated causing the interferences.

RE: Engine Interference
 

I was just going to ask if you used a wire cable or wire pushrod to the throttle. That could very well be the problem.
Dennis-

RE: Engine Interference
 

Make sure the muffler is tight.

Any metal to metal contact should be investigated.

Even a loose engine mounting bolt or a metal to metal contact of a throttle control to carb connection.

Loose parts inside the receiver could cause a problem.

Intermittant wiring connections could be a problem.

RE: Engine Interference
 

Pull out the Rx and tap on it with something and see if that could be it. May be a board or crystal problem that vibration is adding to.

RE: Engine Interference
 

are you using a metal clevis at the engine control arm that is also metal? That could be your problem.
try a plastic one.

Also balance your prop, check every inch of the plane for metal to metal contact.

How old is the battery, I've seen old batteries cuase interferance just before the solder came loose in them and failed

I've seen metal pins used to attach the reciver antenna cause interferance.

I've seen tailwheel set up that have cause interferance when slighly loose.

I've also seen long servo connections, thoe as long as the reiciver anntena tpo be specific cause interferance. This is usually only a problem with large gliders though and can be remidied by putting a 3" extension on or a servo filter in line witht he long servo lead.

RE: Engine Interference
 

Thanks for all the info. I have plastic clevis and pushrods. I put more foam under the receiver and gave a extra tweak on all the screws. I did tap on the receiver with radio on but it did not cause any interference. I am going to start it up tonight and see what happens.
Thank,
Matt

RE: Engine Interference
 

I asked the question below and it is posted now. Here is a great response recieved. Might help.

I started to read Dan Williams article, “Broadband Over Power Lines”, from April’s Model Aviation with great interest. In the article, Dan mentions interference from metal-to-metal noise from linkages. I want to present this topic at a technical / detailed level at a club meeting and would like to understand it fully. Can anyone either fill me in or provide where to find?

John 373786

Given that 99% of interference emanates from within our own models, I'll provide the following explanation-

There are two primary sources of interference, ignition and metal to metal. Ignition noise (relates to gas engines of course) is broad spectrum RFI radiated from the ignition system when the plug fires. This is a no brainer. Nothing more need be said about this form.

The second form is a result of two similar, or worse yet, dissimilar metals abrading. This source is caused by Thermo Electric emc’s. When there is a difference in temperature between two dissimilar metals, a current flows. The friction and vibration provide for that temperature difference. These currents can be quite large depending upon the frequency, or rather the magnitude of make/break contact of the two metals. The magnitude of the make/break is provided by the vibration of the models engine.

The currents generate and radiate RFI in a similar manner the ignition circuitry. Due to slight differences in the metalurgy of same type metals, these currents also flow in similar metals but at a lesser magnitude.

Interference from other sources such as automated machinery, remote controlled cranes, etc. are very rare. These are the items that make use of frequencies between ours. Unless you’re flying from the parking lot of one these facilities or construction sites, the likely hood of be interfered with is negligible.

You stand more of a chance being shot down by your buddy at the field switching on by accident.

There’s a third source of interference we experience as a result of conductive emi, and associated anomalies due to high transient currents and supply distribution within the model. This however is controllable through methods such as separating batteries for servo and receiver. This type of emi interference has little to do with this topic, though.