Hi All,

I am new to the R/C'ing and I have a trainer 40, however a friend of mine is building an old Thunderbug 40 from Balsa USA. His instructions do not tell him how to mount the servos on the plane and since it is a low wing plane I am guessing he would have to mount the servo's upside down. Am I correct on this? Also on that specific plane what is the distance that the engine should be from the firewall as the instruction or manual doesn't say anything about either one.


Thanks very much in advance,

Wrong,on the first question,doesn't matter on the second question,can move it to help the c/g but it doesn,t help that much.

The servos do get mounted upside down with a low wing plane as compared to the way one would install servos in a typical high wing plane. Have your friend carefully study the layout of the inside of the fuse as to where to mount a couple of simple rails running from one side of the fuse to the other. The servos will mount onto these rails 3 abreast=elevator, rudder and throttle. I assume that a servo in the center of the wing controls ailerons so don't mount the servos in such a way as to interfere with the aileron torque rods. Set your motor on the mount and position forward enough to have the prop hub clear the front of the fuse nose by an eight of an inch or so. If you go to a flying club ask some of the guys there for help. Most fliers are more than delighted to share.

Where are you located in PA? Just curious. Big state and wanted to know where.

Servos will mount upside down with the plane in proper orientation. If you look on the plans the mount location should be on the drawing of the firewall. I built a Balsa USA Thundebug 60 for a friend of mine this past spring. The instruction book was lousy but the plans showed most of what you need. This is a relativly easy kit to build but with the instructions as they are it was helpful to have some prior building experience.

It gets a little confusing. Does this help?

Ok his plans shows the Servo section, but not the way the servos are to be set up or anything. I do agree on the instruction book as it only has about 6 - 8 pages total. This is his first plane that he has built from scratch so he is kinda in the dark and it is all new to him. He is also at a loss on how to build the pushrods. Does he need to use 1/4" dowel rods to use to build the pushrods or does he just use the metal all the way through?

Thanks for the very helpful info.

Yes it does help tremoundously. Thanks very much. I will pass the info on to him. I just sent him the link to this forum so hopefully he will join here as well too.

Thanks again,

I just wanted to THANK all of you for your help. It will be applied.

Again Thanks all.

PS. Wish I had of known about this forum and posted here before attempting to take my Trainer up the second time. Maybe my trainer would be in one piece now, :disappoin , LOL.