I am finishing my Super Reaper and am trying to decide if I wan't to cover it with Monokote or Glass it and paint it. What do most of you Reaper pilots think? Which did you do? Also, The vertical fins seem kind of soft and I think that it will help to glass them. Did any of you beef up the balsa parts like the fins or stab? It will have a Ram 750 on it.


Thanks!

Gene

I'm finishing my Reaper as well. I chose to cover it with Utracote because I heard that it worked better with obechi. This is the first time that I have used it and I think that it's great. As far as the obechi, I wish that the wings were sheeted with balsa. The skins have cracks running parallel to the leading edge. The skins were sanded as mush as I felt was prudent without compromising the strength and the cracks show through the covering...maybe resin and glass would be better.

As far as the fins go, let's just say that the British either hit it (Spitfrire) or they don't (Fairey Swordfish). I redesigned the fins to make them more palatable IMHO. They seem to be stronger as well (see below).

I read comments that the aircraft would "run out of elevator" on landing, so I enlarged the elevators. This lead my to think that the stabs could be a little weak, so I added .007" by .500" carbon strips top and bottom to the stabs.

And here's a pic of the stab with the carbon. I basically added 1.5" to the root of the elevator and tapered it toward the tip. This made the elevator trailing edge straight rather than swept

Hi Gene,

I think it all comes down to how you want it to look and how much effort you want to put in to the finish. There's a lot of wing to sand. In retrospect , I would have covered it with Ultracote but I wanted to experiment with certain finishing techniques. The weight difference between the two isn't such a big deal. I'm flying mine on a slightly anemic MW54 that's only putting out 10 lbs and it flys just fine with a top speed of 120 mph.
DO make sure that your stabs are well attached. I fell prey to the "good enoughs" and almost lost it on the first flight when I got severe stab flutter.
Check out my gallery for a pic.

Hey don't blame "Gene" for my comments....that's not me. .

Anyway, thanks for the caution. I added .750" hardwood dowels to the fuselage to mount the blind nuts for the stab screws. Sorry for the poor quality of the pic. I think that you can make out what I'm talking about. I put large aluminum washers under the heads of the mounting screws as well. My reaper will be powered by a JDE 54 and I hope to have it at MESA in a couple weeks...

With Marc's advice, my buddy and I strengthened the base of the fin where the bolts go through by inserting 3/8" dowels through the balsa, and a wedge shaped piece of spruce inside the fuse so the blind nuts will sit at right angles to the bolt.
Because we are using a heavier engine, and seem to be adding weight behind the cg, we are going to epoxy the fins on, using the bolts as clamps. When dry, we will pop the bolts and blind nuts out, and epoxy carbon fiber shaft to fill the holes. Hopefully, at that point we can remove some of the added spruce wedge as well

The wings and fuselage will be covered in Ultracote, and we may possibly do the stabs and fin with glass - but that hasn't been finalized yet...

The repear has been discussed pretty well, check out old postings..

I used Monokote for everything. The small checking in the obechi is not too noticeable on mine, but monokote is fairly "heavy" and covers them well.

I ended up glueing on my stabs and canards for safety. I did use bolts with washers too. No chance of them coming off, and I did never have a flutter issue. I am using digital seros and very stiff links (carbon fibre) with sealed surfaces.

As for running out of elevator, if you balance at the 530mm point as recommended you will NOT have a lack of elevator even without elevon mix. Trust me!

Good luck, its a great flying plane. Super smooth and aerobatic too!

Andrew Coholic