I recently bought a nexstar 46 RTF. Can someone please tell me what the reason is for wrapping the Rx (and Rx battery for that matter) in foam? The only reason I ask is because i've been running 1/5 scale onroads, offroads, and boats all with gas engines with the Rx's fastened by double sided tape and the Rx batteries by velcro straps. I have never had any problems. One time, the Rx in the boat actually fell off the tape while running and was bouncing around inside the radio box and still not a problem. Now all of these vibrate a lot when running. Im sure a plane doesn't vibrate any more than my other r/c's. So whats up with the foam then?

It is to protect them from vibration. If the crystal breaks in the rx or a contact breaks in the battery, you are going to lose the plane. Not necessary so with a boat or car. Note that the new 2.4Ghz receivers to not have crystals and therefore the need to wrap them in foam is not really necessary.

Br;uce

Generally the foam is there to help with vibration and I suppose it could help a little with rough landings and minor crash impact in some cases as well. I have seen people fly without wrapping batteries and receivers but I prefer to play it safe. At the very least I have a layer of foam underneath if it is not wrapped completely.

Hey thanks Bruce. I was just reading on another site a whole article on 2.4g Rx's. They are not affected by vibration like the old stuff is. Iguess I should have done a more thorough search before making a new post.

Chuck, yeah that sounds like a good idea. One layer of say 1/2 inch foam then mount the battery and Rx on top.

Foam is cheap and light. You can't go wrong with a thin (perhaps 1/4 - 1/2 inch of foam) at least on the bottom of the receiver. I use something like this:

http://www3.towerhobbies.com/cgi-bin...?&I=LXMRC7&P=7

and then tie-wrap the receiver to the mounting platform under the wing. I don't wrap it in foam, just sandwich the foam with the receiver on top, the foam in the middle, and of course, the mounting platform on the bottom and then I put a couple of tie wraps around to hold it in place. Since I've move pretty much over to 2.4 GHz operation, this works fine.

One big advantage to this method is that you don't foam completely wrapping the receiver so you have direct access to all the servo connectors, the battery connector, and of course, the binding slot for the binding plug.

CGr.

Why is that, Bruce? If it's 72 MHz, you still have a crystal. And you still have vibaration caused by the glow powered engine as well as vibration from driving on land or of boating over the water.

CGr.

Careful with 2.4....it's best not to wrap the receiver in foam...instead place foam at the corners of the receiver to allow cooling air to circulate around the receiver

True. Futaba says the same thing.

Yeah......we were talking about this the other day. I just mount foam on the airframe with double sided mounting tape and then mount the receiver on the foam with double sided mounting tape. I have this in several models and it works great with plenty of air being able to get to the receiver.

Does the double sided tape keep the Rx stuck to the foam by itself, or do you use a zip tie on it as well?

CGr....When a RX stops working in boat, your dead in the water. When a RX stops working in a car your dead on the track. Either way you just go and retrieve your boat or car. When a RX stops working in a plane, you go and retrieve the pieces.

Tom

I think I understand that part of flying RC.. you see, I've done it for quite some time now.

I'm not sure that's what Bruce meant. But if his comment was that simple, then I can accept that. MY point is that vibration is vibration and causes the same problems with receivers no matter what they are installed on.

CGr.

CGR, good question and I don't know the answer. But I have noticed that the majority of car/boat people do not use foam around the receiver. Could be they are not as concerned about the consequences of losing the radio because it does not always mean the total destruction of the vehicle.

I should have added to my post the fact that I do mount my 2.4 Ghz receivers on a pad of foam using tie wraps or velcro unlike my 72 Mhz receivers which I wrap in foam.

Bruce

Folks,

Here is what Ifound for my Spektrum AR7000 RX from the manual at link

"Receiver Installation
In gas and glow aircraft install the main receiver using the same method you would use to install a conventional receiver in your aircraft. Typically, wrap the main receiver in protective foam and fasten it in place using rubber bands or hook and loop straps.
Alternately, in electric airplanes or helicopters, it’s acceptable to use thick double-sided foam tape to fasten the main receiver in place.
Mounting the remote receiver in a slightly different location, even just inches away from the primary receiver, gives tremendous improvements in path diversity. Essentially, each receiver sees a different RF environment and this is key to maintaining a solid RF link, even in aircraft that have substantial conductive materials (e.g. larger gas engines, carbon fiber, pipes, etc.), which can weaken the signal."

Yes the tape itself holds the Rx just fine. The tape I am referring to is servo mounting tape and it sticks really well. I have had to take out an Rx once or twice and it ripped up the foam and was somewhat challenging to get off of the Tx but with a small amount of Goo Gone it came off the Tx just fine. If you are nervous you could also use a zip tie but I don't and have not had a problem.