Hi all. Return to hobby after decade and converting Funtana90 to electric. Haven’t had any success researching mounting it, I’m sure just randomly drilling new holes in firewall is good way kill performance of airframe or worse. Is there a formula for this? Like to be as close to the money as possible and not just eyeball it with cowl or old glow mount. Any help or reads I’ve missed would be greatly appreciated.

Nick, welcome back. There are many variables that need to be accounted for before anyone can offer accurate advise. Knowing if the motor is set up to be rear mounted or front mounted would be the first thing to know. I'm going to assume that the cowl has been previously mounted. This should actually be a help. My suggestion would be to first determine if the firewall has any offset for right thrust or not. Some models will have it built into the firewall. If yours does not I highly suggest you add it. This will make takeoffs much easier. This can be done by just shimming one side of the motor mount with some nylon washers. Once you have determined how far the motor needs to sit off the firewall, add the appropriate length stand offs. To figure out standoff length, mount cowl and measure the distance from firewall to where you want the prop drive washer. Suppose that dimension is 7". Now measure the distance from the back edge of the mount to the face of the prop drive washer. Suppose that dimension is 4", then your standoffs need to be 3". You can fine tune with washers. To get the proper mounting hole location, stand the fuselage vertical, place the motor on the firewall and mount the cowl. Position the motor so the shaft is centered in the nose ring and then mark the firewall where the standoffs or mount contact the firewall. Don't forget the right thrust, that will require you to move the motor off center slightly.

Thanks. It’s front mounted and has right thrust built in(funtana 90) about cowl for help with motor alignment sadly I’ve lost original cowl and plan on making one after motor install. Should motor be perfectly centered or inline wth center axis, wing? Old glow mount holes still are there. Thanks for any advice. I have lot to catch up with especially with electric move.

The vertical position won't matter much unless you are talking several inches. The main thing is no down thrust and a couple degrees of right thrust.

What are you using for a motor, ESC and battery on that Funtana 90. I have one that I was considering electrifying.

Thanks for good info! I’m using a Dualsky 5322 380Kv motor on 6S with 120a yep esc,first prop I will be testing is 18x8e app, not thrilled will 8 pitch on this airframe(seems little hot for F90) originally powered it with saito 125 on 17x4 prop but it has been recommended more than once and using eCal pitch is how to enter power band on these electrics. The saito was bit underpowered for pullout so really hoping this power system will get the job done.

Been almost decade since I’ve flown besides a buddy’s trainer plane couple weeks back so spending lot of time on simulator and found by 3D stick skills are still there but just flying around I’m jumpy and will scare other pilots so no hurry to put her up.