I have ordered a GP Revolver... I don't think they give me an option to add my servos to the rear, only the center... but my engine the Rossi 65 weighs in at 700g as suppose to the recommended engines at 550g or so... so I am just guessing that I will need to cut out spaces in the tail to add servos... what do I need to get to cut out neatly? or what do you guys normally use?

I'm gonna be moving the servos back on my extra eventually and I plan on using a dremel with a cut off wheel. Be sure to add some light ply to the mounting area where the screws will go through.

that was a quick reply... thanks man... will do...

NP, I just happen to jump on right after you posted it and you were first in line.

sweet... I hope there is enough balsa in the rear of the Revolver... I have not received it yet so I don't know...

Probably so, being made by Great Planes means it will be well constructed.

then it shouldn't be a problem... they do construct well and that's the cost I had to pay... its the only plane fitting the profile that I wanted... but it was pricey... well in SA money R1000 more than say a Hangar 9 Sundowner which is in its class of size... bad thing is I am off to Germany for 5months... she is staying behind... have to go work up there...

you shouldnt even need a dremmel, a exacto knife will do just fine for cutting out a hole for a servo, then a couple of small pieces of light ply or hard balsa will do for the mounting screws, just harden the screw holes with thin CA and your set.

I did the same to my gizmo kit for balance since I was using a engine at the top of the range for it, having servos in the rear also makes your control surfaces more responsive a bonus.

cool man... yeah I will check what will be fastest and easiest... but I definitely need to have them servos in rear...

Due to the torque you will need for both the rudder and elevator, I would make darned sure you attach the servo mounts to a hard point, not just skin balsa back there. Perhaps the light ply between two formers and a piece of 1/4" square hardwood on both ends where the servo mounting screws hold the servo in place (behind the balsa and CA'ed in place). Just attaching it to balsa, especially the thin skin balsa, is not a good hardpoint at all for holding in and securing servos.

CGr.

for sure... I was planning on adding supports on the inside... will use ply wood probably or as you suggested hardwood...

I was going to post these photos last night, but when I did they were giant on the page.

here is the plane I was refering to,my Gizmo sport plane, oversized barn door ailerons, rudder,and elevator, the fuse sides are 1/8" balsa sheets, and the screw holes are strengthened by some small pieces of 3/16" balsa stock the holes are hardened by the thin CA like I mentioned in my earlier post.

there surprisingly strong, really no need to go overboard with making servo mounts overly heavy, strong yes of course, but adding exessive wood is really not necessary, as long as the structure is sound at the mounting area, and the hole is the exact size of the servo body this helps counteract the torque of the servo, the screws really just hold the servo in place.

a pre crash photo, and its new red color scheme, had to rebuild the front of the fuse and recover the wings after a little mishap all good now

good to hear, hopefully the tail area is nice and strong already... cause I will have a hard time getting extra supports in there...

Yeah, with ply for fuse back there you really are good to go. I would still put a piece of 1/4" square stock back there for the servo screws to grab into, which you might have done, bigtim. I put that little addition on every servo I install. It just adds that little bit of strength to help hold the servo steady.

CGr.

I did, after I cut the holes, and fit the servo so it slipped in nice and tight,I pulled the servo and impaled a piece of wood cut to fit with a exacto knife at a slight angle, with some med CA I slipped it into position on each side where the screw holes were.

after putting the screws in a couple of times to open the holes, I used the thin CA to harden the wood, pretty standard stuff for the exierienced builder, but sometimes overlooked by the beginner builder( why I mentioned it )

if you don't harden those screw holes in balsa, and light ply, the screws will almost always loosen up and can really cause problems, like servos coming loose and your plane crashing, light ply is really weak in the center of it, after a couple of drops of CA in a screw hole it strengthens up alot

I checked my kit last nite, the tail is pretty thick from ply... I don't think it will be necessary to add supports else I would have to get longer threaded screws...

Yeah, BigTim.. I forgot to mention that, so thanks for doing so. I always hit a drop into each hole. I put the screw through to establish a thread then hit it with CA and blow into the hole to make sure it doesn't set up into a glob but gets into the threads, then let it set up for a while. Then I carefully chase the screws through and set them in snugly. It's always worked fine for me and I too have never had a problem with that. Often, the CA may be somewhat "wet" in places which really sets up with the servo screw and forms a bond which will come apart, but is tight and secure.

A good reminder for sure, and a good practice.

CGr.