I am building a 4*60 arf. The manual is not real clear as how far the prop should be out in front of the fuselage when mounting the engine. Is there a standard for this?
Need some help.

thanks

Hi you diden't mention what engine you are using. I just mounted a saito 91 on mine. I is mounted all the way out on the end of the beams. I still had to add 1.5 oz of lead to balance. Also the battery is pushed all the way to the firewall under the tank.

Yea, I guess that would make a difference. I am using a Irvine 72. It sort of sounds like
the balance of the plane is a main consideration when mounting the engine.

I have a TT .91 in mine. The TT is a really heavy engine, but I was able to move the servo tray around to help with the balance. Don't know if you can do this with the ARF or not. With the Irvine, you'll probably end up tail-heavy, so moving it forward as much as possible would probably be best.

Camtek, I put a .91 Saito in mine also. ( It was also tail heavy.) Instead of adding nose weight, I made two steel flatbar extensions that bolted to the engine mount rails and let me go way out with the engine. A Cline System was just enough weight to finish balancing it.

i just flew mine for the first time today. i have a super tigre 75 on it, it is mounted pretty far forward with the prop about 6 inches forward of the firewall ( engine and mount came off another plane where this was required) this makes the plane nose heavy so the batt. and reciever are both mounted at the rear of the radio compartment as are the servos. flies awsome tho.

I am currently finishing a 4 * 60 kit, just need to cover it now. The manual with it states to mount the engine so that the prop clears the cheeks by 1/8 to 1/4 of an inch. With 0 degrees of Horizontal thrust, and 2 degrees of down thrust. Regardless as too what engine you are using.

On my ARF I mounted a OS91 Surpass by making sure I had enough room for the fuel and muffler pressure lines and in front of the cheeks like 'The_Matrix" said. However, if I had it to do over again, I would have moved it further forward. I ended up putting a lot of weight on the nose. Also, not sure if you will experience this problem or not, but watch the cheeks when your engine is running. Mine had a lot of vibration and the left fuse cheek began to pull apart from the side of the fuse on the bottom. I fixed this problem by taking a dowel and running across in front of the engine and drilling holes through the fuse sides and into the dowel. Then I screwed in a couple of Cowl screws with washers. No other problems with the vibration since then.

Have a OS61 fx. I taped the engine in place, balanced the plane while moving the engine back and forth. When I got the balance correct, I marked the holes in the mount. Turned out the engine is pretty far forward. I did not have to add any weight. flys great.

Michael

Hello,

This is only my second plane, but here is what I did. With the electronics installed and the wing attached, I balanced the plane by moving my Saito 100 to the correct location on the mounting beams. Voila! Perhaps the same technique would work for you?

Good luck!

Travis

I have a 4 Star 60 (ARF) with an OS 61, the trailing edge of the prop is 1/2 an inch from the front tip of the fuselage sides, that's 5 inches from the bulkhead to the trailing edge of the prop,,, the plane balanced prefect, no need for extra weight...


jim

I measured mine with a Saito .91. It measures 1 7/8" from rear of prop to front of fuse. No weight added.