boisebiker

Have an Austars-model Edge 540 that I picked up with a Supertigre 3000 in it. Can't get it to run consistent, too many dead sticks, and I have MLD28 sitting in the box. So I need some help. How do I fill the holes in the cowl that were cut for the 3000? The pics show MLD mounted temp, holes in the cowl, and a look at the plane.
I have many weights and weaves of fibreglass, enough epoxy to do many jobs and a little experience. I tried to contact the company to order a new cowl but have never heard back. Also any tips on modifying the plane for gas would be great. Need to add 1/2" to get the engine at the right location for the prop to meet the cowl, what is the best way? MLD comes with short standoffs, might get 1/2" longer ones. Just finished fixing up a Wild Stik with a RCGF 26cc, had to push firewall back 2" and move tank to CG.

Thanks for any help,
Boisebiker

PS I know it is dusty, been in storage for a while. Will post more pics if needed.

aussiesteve

Easiest way to cover the holes in the cowl is to put some masking tape on the cowl around the hole then tape some cardboard over the outside of the hole and give it 2 layers of 4 or 6 oz cloth . Remove the cardboard once the resin has set sand the surface down and, mix some microballons with epoxy and fill in the low points then sand and paint.

It is also possible that you can get another cowl from another source. Most ARF manufacturers by their cowls in from other companies so it is quite likely that a cowl from another brand will fit.

For spacing the engie forward, a little longer on the standoffs should work fine.

For your Wildstick - watch out - they are a blast to fly and you will get addicted pretty easily. I have a similar setup to what you have described on yours (different engine) and it is a lot of fun for sure. I also shortened the nose and moved the tank on mine.

boisebiker

I have heard of the micro ballons but have never seen them, do they disolve in the epoxy or just add body? How do I keep the epoxy from sticking to the cardboard, thought I might use some clear wrap or wax paper from the kitchen? Most of the holes are on curved surfaces and I think I may need some type of molds.
Any sugestion on how to look for a cowl that might fit this plane?

aussiesteve

The original microballons are a coated phenolic bubble, nowadays there are also glass bubbles (hollow sheres) available from some manufacturers. They add body and viscosity but also give good sanding properties. You can also use a good quality lightweight automotive body filler if you don't want to go that route. Speak to your local fibreglass materials supplier to see what is readily available.

In the method I offered, you don't worry about the epoxy sticking to the cardboard, you just sand off the excess cardborad during the finishing process (Sanding and filling). Wax paper will work as will clear wrap.

If you want to make a mold, you could use plaster of paris, sand it and varnish it but by the time you have done that, you may as well have done the repair "freehand".

boisebiker

Will probably freehand the glass layup, now just need to figure out how to match the paint scheme.

boisebiker

Finished the glass work but have issues. I cut some card stock just larger that the opening. Taped the card to the cowl opening with aluminum foil tape(love it). 3/4 oz of resin, 3/4 oz of hardner, 1/4 oz of denatured alcohol. 3 layers on the small holes, 4 layers on the large holes. I used very light glass for the first 2 layers trying to get it into the edges and last layer was thick glass. Had a small amount of epoxy run under the card, not bad will need a little sanding. Problem is that the new glass and epoxy is rubbery. The original cowl is hard, the filled holes are soft. Why did the epoxy stay soft? Mixture issues? Let it cure in the basement where it has been a little cool. I will add that the ratio of epoxy to glass was not ideal, way more epoxy than fiberglass.
Other than the softness the shape came out excelent. All of the curve were maintained. I may put another layer on the outside and sand it down. Some paint and it will look like there were never any holes in it. Will post pics tonight.

boisebiker

Pics with the glass complete. You can see the image on the card stock transfered to the cowl. Still need to sand the outside and possible add another layer to clean up the bubbles that were in the glass.
I think the shape came out really well, just need to figure out why the glass/epoxy same out rubbery.

RTK

My Feedback: (1)

The epoxy should cure to a nice hard consistency given time and/or a warmer environment

boisebiker

I messed up!!! I got impatient. I thought I needed another layer of glass to help stiffen up the repaired areas and fill the small voids left in the repair. So I put another layer over the top/outside. The original fix did harden up after some time but now I have to deal with the extra layer of glass instead of using some gap filler/bondo. Now I have a lot of sanding to do and will probably still need the bondo. Oh well live and learn. Now I am trying to figure out why the MLD28 won't run smoothly. It seems to cut out a lot in the higher rpm until it has warmed up a lot then will peak out. Can't tell if it is needle settings or the ignition. Needles are very hard to adjust on the test stand, will need to fix that.
Also been playing with water bottle tanks. I have tried bulkhead fittings and gas stopper. Both seem to work but right now I feel more confident in the stopper than in the bulkhead fittings. In the smaller bottles the wall thickness is so thin I am afraid the bulkhead fittings will pull through. I have 10oz bottle in my Wild Stik for testing with bulkhead fittings, one in the cap and one in the side of the bottle(pics to come).

boisebiker

Getting closer, just 2 more colors to paint. I have to say this painting stuff sucks.

Also remounted the MLD28 inverted on the engine stand and the high rpm miss went away. Now I have to test different props and see wht rpm I can get and choose one best suited to the airframe.