How to mount Radial motor in FT Explorer

Battenkill

New member
Hey,
My son and I are working on our first build, FT Explorer, and all is going well. We are following the assembly video closely and have run into a question that has probably been covered on here before (I tried searching for info, no joy); we are using a Power Pack C and ready to mount the Radial engine. However, the C engine used in the video is different. Can anyone provide a link showing how to assemble the Radial motor to the Explorer's engine mount? Thanks.
 

BATTLEAXE

Legendary member
Welcome to the forums, great choice on the Explorer, great plane. As far as your issue goes I am guessing you got the C pack Radial and the build vid uses the old Emax. I think the old Emax mounts inside the nacelle with the shaft poking out. You can mount yours on the outside, won't make a difference
 

Battenkill

New member
Thanks for the response. That makes sense. Let me ask some more assembly questions, if you don’t mind: I think this would be the most sturdy way to mount the motor to the nacelle: (option A) machine screws through the firewall into the back of the motor. However, that makes for a tight squeeze on the bottom where the wires run over the corner and then under the wooden nacelle.

9B510DC1-22DA-437A-8E31-9F1F61FFC10E.jpeg


(Option B) I can alleviate that by using this spacer, but that requires me to mount the motor to the spacer and then lag the spacer to the wooden firewall. Kind of awkward and seems destined to vibrate loose. Then again, I am the king of over engineering (if it’s worth doing, it’s worth over-doing).

D4BBC2FF-999A-47E5-AC54-8813EB0AC6AB.jpeg


Lastly, the prop just slides on (lettering facing the direction of flight) and comes to a snug fit on that shaft, with no bushing needed, and then that lock nut to hold it all in place. Is that the correct procedure?

Thanks again. I don’t mind learning from my mistakes, but would rather learn from other’s.
 

BATTLEAXE

Legendary member
There is a way to do this, and it's a little of option A and a little of option B. If you have any small washers, 8 of them actually, you could double washer each machine screw between the motor and the firewall. That would fir out the motor enough from the firewall to get clearance for the wires you are looking for. But really the motor is designed to fit right up to the firewall and those wires coming out can really take some abuse, mostly from crashes. They are designed strong enough at the motor housing that you can form them to fit on the firewall flat. They are always kinda stiff to move when they are new but they do fit better after a few hits lol
 

Battenkill

New member
Haha... I hear you about the crashes. I see many in our future! Thanks for the explanation. All makes sense. I think just working through this has helped, as I see that I can get that motor right up to the fire wall w a little effort. No need for spacers. Good to hear the wires are tough. Didn’t want to force it.
 

quorneng

Master member
Might I suggest that you place a washer, preferably the diameter of the prop hub, both behind and in front of the prop.
This will ensure you can tighten the nut without damaging the much softer plastic hub. Remember it is the hub that stops the prop blades from becoming "flying knives". :eek:
 

Battenkill

New member
Might I suggest that you place a washer, preferably the diameter of the prop hub, both behind and in front of the prop.
This will ensure you can tighten the nut without damaging the much softer plastic hub. Remember it is the hub that stops the prop blades from becoming "flying knives". :eek:


Great point. Flying knives = bad... unless they are flying on purpose.
 

PookaHat

New member
My first ft build. The first motor I tried was pre-fried so I had to scrounge around.
After the first attempt I used an out runner 480 that I salvaged from a Horizon BNF Valiant. It took awhile to open up the holes in the mount but it’s in there.
I found that I had to glue it in about 1/2” higher in the pod. The wind has been in the 20 mph area all week so there hasn’t been a maiden crash yet.