Fuel or electric

[PurpleHaze]

I ventured out into the modelshop few days ago and ran into someone that came in to buy a new plane. He (experienced pilot) crashed his plane because of the electromagnetic field of the engine (at least that's what I have been told). He trew the plane into a curve and when the engine alligned with the receiver and the transmitter (thus being in the middle exactly) he lost control. Just for a second but long enough for his plane to turn into a submarine. He told me glow engines never have this problem but he experienced it with (big) electric engines several times.

So now I'm working on an uav platform (mainly for video) and I'm still wondering what would be the best solution for an engine. It's a 108" wingspan .60 model.

I already noticed that these BIG electro engines are more expensive then fuel ones (incl the speedcontroller).

In addition it will be a video platform with a downlink, probably 2 receivers and other electronics. So relatively sensitive to interference.

On the other hand, it will be an uav that might crash, fuel engines carry fuel that pose additional hazard when going down. Electro is "less" dangerous. Then again, if the above matches reality, chances of "problems" are fewer with glow engines.

I guess the military shows which choice is best (most military UAV's run on fuel).

Or am I wrong? Is it a known "feature" that big electro engines could cause interference when conditions are met?

[Miami Mike]

I think you need to consider showing a little skepticism here. Even if that story of his about electromagnetic fields was true, how could he possibly know that it was the real reason for his crash?

Receivers typically have antennas about one meter long. There's no way that an electric motor or a glow plug engine can completely block the signal from any angle.

(With a 2.4 Ghz spread spectrum system, it may be possible.)

[PurpleHaze]

I think you need to consider showing a little skepticism here. Even if that story of his about electromagnetic fields was true, how could he possibly know that it was the real reason for his crash?

Receivers typically have antennas about one meter long. There's no way that an electric motor or a glow plug engine can completely block the signal from any angle.

(With a 2.4 Ghz spread spectrum system, it may be possible.)

Thanks Mike, that's why I asked. But it sounded plausible at that stage really. Then again the radiosystem uses hf emf and the engine would normally cause lf emf. Not sure if they can cause eachother trouble but I dont think so. The engine however might be capable of generating an emf frequency in range of the radio signal (dont ask me how, maybe speed/voltage related) that could disturb things?

He told me it happend few times before, everytime when the plane was facing him. Don't know, could be a clue, could be not. That's why I asked if someone else suspects this kind of behaviour or better experienced it.

Don't know what kind of radio he used to be honest. Could be a spectrum as they also sell them in that store.

[PurpleHaze]

So I guess everyone agrees that electric is as fault proof as glow engines? I'm working on an UAV so it's very, very, important that it doesn't come down and I pick the right engine.

Thank you!

[vintage1]

Purple Haze? a strange name...

Nothing is foolproof and nothing is reliable.

Electric motors and controllers produce a steady rasp of interference. Glo motors pack up and dead stick.

Electric motors can be stopped and restarted for vibration free pictures. Glo motors mostly cannot.

In the end you pick the best staring point and work on the bugaboos till they are 'good enough'.

A decent brushless setup at least eliminates brush spark noise. If you take care with the installation most of the other noise will be well below the noise floor of the electronics anyway.

Making an earthed brass box for your receiver will help with out of band interference. I am plagued by a microwave tower that pumps tens of watts at 35Ghz in a tight focussed set of beams..fly across one of those, and I lose signal

That isn't a crash tho. The motor just 'misfires' a bit and the occasional twitch happens.

You can add toroids to all leads as well, and buy a good quality receiver..or if you can accept the slightly reduced range go to the 2.4GHz band.


Ensure no metal to metal vibrating linkages - especially brass to steel..either insulate them of connect firmly using a flexible braid..

Do all that and you will have a rock solid model..until someone else switches on a transmitter on the same channel :D

[PurpleHaze]

Purple Haze? a strange name...

Nothing is foolproof and nothing is reliable.

Electric motors and controllers produce a steady rasp of interference. Glo motors pack up and dead stick.

It's a Jimmy Hendrix song and the color of my "slow poke" (the latter is a plain and is no way related to the warrior that carries the same colours) :D

I'll go for fuel just to make sure. The current plans incorporate quite some electronics. Don't want the engine to pull to much from the lipos and I really have to avoid interference.