flystright

My Feedback: (13)

Hi, Installing a G20 on a F6F Hellcat 60. Was told that when using gas engines that you could have radio interference problems. Also that the G20 is power hungry. Here is a photo of the system I would like to use. Question is. How good is this setup.

Thanks for the Help

MinnFlyer

My Feedback: (4)

You do not want to power your Rx with the same battery you're using for the engine ignition.

Think about it: If the engine burns up its power, it will loose RPM or quit - bit as long as it is using its own battery, you'll still have control. If they share a battery, you may lose control before the engine quits.

sandal

Is there anything in his setup suggesting that he is going to use the same battery...? I believe he has only mentioned the ignition system. OTOH, keeping them separated is definitely good advice.

MinnFlyer

My Feedback: (4)

Yes, look at the setup - one battery is powering both

sandal

Sorry if I'm slow, but I can't see a receiver at all in his drawings. The only thing I can see that has anything to do with his receiver/servo circuit, is the connector from the optical kill switch to the Rx, but this doesn't cause any interference.

flystright

My Feedback: (13)

The RX system will be separate from the engine system I will be using two batteries.
Batt #1 RX 5cell 2000mah
Batt #2 eng. 4Cell 2700mah

This is what I came up with in doing research on the G20 in the Hellcat. Just won't to make sure.

Thanks the advice.

MinnFlyer

My Feedback: (4)

Ok, I read it wrong

flystright

My Feedback: (13)

Could have been how I stated. Making dwg in Microsoft Paint for whole system will post for input. I work for a electrical outfit, This is what I like to do.

flystright

My Feedback: (13)

Here is the DWG that I just finished. Please give me your inputs on this layout.

Thanks.

jrcaster

The electrical hookup looks ok. The only thing that doesn't show up in diagrams is that I beleive that you need to have a metalic surface on your firewall. Something like copper or aluminum foil epoxied to the front. Also you don't want a metal clevis or pushrod going to the throttle. Last point I beleive the fiberoptic sender goes in the fuselage with the receiver, and the kill switch goes in front of the firewall with the engine ignition battery and ignition.

One last thing, you didn't mention what radio you are using. 2.4Ghz are not as sensitive as the 72Mhz systems for interference from the engine.

flystright

My Feedback: (13)

Thanks for looking. What is the copper or aluminum for, is it heat or interference or both. I was going to use a fiber rod easy to get around gas tank. As far as the receiver will the heat bother it, also need to place where their will be no kinks in fiber line, any idea's? I have been doing a lot of home work on this setup, would like to have all my "T's" crossed and "i's" doted before I begin building. (Vibration of from engine.) What would be the best way to mount?


Thanks for the help

MinnFlyer

My Feedback: (4)

Metal on the Firewall is not really necessary, but a non-metalic throttle pushrod is.

flystright

My Feedback: (13)

Question what servo size do I need for the throttle. Here are some picts on how to mount the G20 and the type of servo's I will be using. If you see something that will not work please speekup. When I finish doing my home work on this plane I will be posting my first build on line.

Thanks for the input.

MinnFlyer

My Feedback: (4)

Any servo will work for throttle

jrcaster

A standard servo should work for the throttle. What radio are you using for the plane? From what I have read you need to set up a failsafefor gasoline engines. That would mean a PCM for 72Mhz or about any 2.4Ghz. The copper or aluminum on the firewall is for interference. Minnflyer knows a lot more about running gasoline engines than I do, so it may not be necessary. Just do a range check both without the engine running and with, and if you get interference with the metal shield would be necessary.

If that is your version of a vibration mount in post #13 you will also need rubber bushings behind the firewall under the flat washers. Also make sure to use nylox nuts so they won't vibrate loose, because with the rubber vibration damping you don't want to tighten the bolts down much more than snug.

When you hook up the kill switch with two modules the kill switch goes in front of the firewall, and the sender goes behind the firewall. They are linked through fiberoptic cable which will not transfer interference.

Crash Campbell

Hi,

I agree with what you have been told thus far but would add that in my experience wrapping the ignition unit in aluminium foil to make a Farady cage is useful to reduce RF interference. This was the only way I could remove it from a twin cylinder ignition unit at WOT.

It is also prudent to have the Rx electronics and battery as far away as possible from the ignition unit and battery, at least 6"min. I would also suggest that as well as having a manual switch for the ignition it is a good idea to have an optical kill switch activated by the throttle kill on your TX.

You will also probably find that the throttle arm on the carby is very short necessitating either a bell crank system or replacement with a larger arm or simply brasing on an extension.

Petrol engines are different to set up but well worth the trouble.

Cheers,

Colin

Crash Campbell

Sorry[]

Now with my glasses I can read that you have a fibre optic kill switch.

Cheers,

Colin

2slow2matter

My Feedback: (1)

absolutely do not put metal on the firewall. Especially if you are using 2.4 ghz. If the plane is flying straight at you, and your signal is trying to go through the firewall to the receiver, you will have a huge shadow, and may lose signal. All of the metal on the engine is bad enough, but there are still exposed "holes" for your signal to travel through. Now if you cover the firewall with a metal foil, you might as well forget it if you ever point the nose of the plane directly at you. Not necessary and asking for trouble. I have several gassers, as do my dad and brother. All you need to worry about is isolating the power (which you have...the fiber optic is the best way to go) and isolating the servo from the engine with a nylon pushrod...as has already been stated.

flystright

My Feedback: (13)

Hi, Thanks Never used bell crank system before do you have some pict's. that I can look at or some links.


Greg

flystright

My Feedback: (13)

This dwg's was made possible from all the great support on RCU.

Hookup DWG's for G20 gas engine. To help reduce Radio Interference and vibration.




Thanks to all for all the help and support.