I have bought a Phoenix Decathlon used about a month ago...

A great plane and a very gentle and forgiving flyer (or so I thought)...I had an unfortunate midair encounter however with a low wing racer (how unfortunate is that?!) which cut my wing in half and the poor decathlon met with the ground abruptly!

As you can imagine I am not an experienced builder, so would appreciate any help in rebuilding this...

I have an extra wing (the guy that sold it to me had it), so the wing is not a problem, however the fuselage needs a new firewall and have no idea how to built one with no plans, from what material I should built it from and most importantly how to secure it on the fuselage!!

I am attaching some pictures and any help/tips from experienced builders out there would be appreciated!

Many thanks and beware of low wing racers sneaking behind you (I beleive the Japanese called them Stukas!!),

Dimitris.

Well, luckily, it's only balsa and plywood! The firewall is most likely 1/4" aircraft plywood, available from the LHS. To get the correct pattern you could (A) piece together the crashed one and copy it, (B) find someone that has the kit and copy theirs, or (C) order a new one from the manufacturer. Most firewalls are glued to the fuse sides, top and bottom (inset into the fuse) and supported on the inside with triangular balsa stock. You may want to look at somebody's kit built plane that has not been covered yet. (Ask around at local clubs), to see how the firewall is built in. Most any type plane would do as an example here, they are all similar. Hope this helps.

Sorry for your loss, Dimitris. I saw a similar mid-air several years ago at the local field. A large Waco was doing a low fly-by and pulled up in front of a VERY FAST-moving Sig Kobra coming up behind him. The Kobra center-punched the Waco's right wing panels. The Kobra's spinner chopped the wings in half, with the expected results. The Kobra landed safely with only minor damage to one wing and the spinner cone. The Waco was totalled.

That's bad damage, but it's fixable. Strip ALL the equipment and hardware out of it. Lay the fuse on the workbench. Note what wood is used and where it's used and go buy the same stuff from your LHS. Use the old firewall to make a pattern. Even if it's in several pieces, you should be able to piece it back together enough to get a useable pattern from. Strip off all the covering from the damaged areas. Some pieces are broken but still attached to the rest of the fuselage. Work these back into place and start gluing, using thin CA. Begin fitting new pieces into place. Glue then in, working from the back to front. Use splices, reinforcements, and thin CA. When you get to a piece like the landing gear plate or firewall, clean up the places where it goes with a #11 and sandpaper and fit a new piece. Use thin CA first, and reinforce with tri stock. After the thin CA soaks in and saturates the joint, run a little thick along the seam. Use reinforcing strips wherever you join two broken pieces or add a new piece. Work slowly and think a step through before you do it. Dry-fit everything before you hit it with the CA. Finally, fill and sand the exterior and recover. Reinstall all the equipment. If you're a not very experienced pilot, I'd advise having a helper with you when you test fly it, and I'd also advise not test flying it when spectators are present. The trim may have changed a LOT from before the midair.

Good luck with it, and keep us posted to the progress.

Here are a couple of pictures of a similar repair I did several years ago. After the repair, the plane flew just as before and had a long life.

Dr.1

Am I not seeing something? It looks to me like that old firewall will just epoxy back in place. Yes, no?

Mike,
You're not seeing things because I see the same thing. Epoxy the firewall back in place. You can add some strength to the firewall repair by drilling and pinning the firewall. It's really easy to do and will add a lot of strength the the repair. Drill into the firewall from the side, squirt a little bit of white glue into the hole, and then tap a dowel rod into the hole. See diagram.

Hope this helps

Ken

From the pictures it looks like to me that the firewall broke into two pieces. About 1/4 of it still attached to the fuse and the rest to the engine. Look at the blind nuts relative to the edge of the piece left.

I would make a new firewall using the two old pieces as a template.

-tychoc

Thanks a lot for all the answers. The more I look at it and the more I read your answers the more I think I should give it a try. I was ready to scrap the plane and get a new model.

I was a bit sceptical of epoxying things together as I do not know if they are going to hold. I am attaching some more photos for your consideration.

The firewall is broken into 3 pieces, so I guess it would be safer to try and rebuilt this. Now mounting the firewall, the fuselage is broken where the firewall was mounted as well as where the support behind the firewall is (shown in the photos) The fuselage is also broken where the landing gear mounts whith the plate detached and still attached to the landing gear.

Would just epoxying all this together, together with some supports be enough?

Sorry if I am repeating my self its just that I have no real experience in building/repairing a plane (actually I once built a pt-40 12 years ago just before exiting the hobby to go to university).

Once again thanks for all the answers, it really helps and it quickly builts up experience for us newbies!

Dimitris.

DO NOT USE EPOXY! Why? It's heavy. It takes a long time to cure. Unless you use really a slow-set (read 24 hours) type and thin it a little, you can't be sure of woodgrain penetration. You'll have a surface bond that will pull off under load. Use thin and thick CA. It will wick into every woodgrain within 1/2" in all directions from the spot you apply it. It's lighter and stronger than epoxy, too.

Dr.1

I'm not going to get into this repair as the others have you on the right path. What I want to say is for future reference. ANY time you crash --- pick up ALL the pieces, take them home and just let them sit for awhile. You will be surprised how much you can glue back togeather, put in a couple extra braces / supports or what ever and end up with a great flier.
There are a lot of folks out there that fly some pretty great planes that came out of trash cans and went back togeather to fly another day or so . Just take your time and think about what you are doing. ENJOY !!! RED

Hi!
It's an easy fix.
Just cut away the remains of the old fierwall and make a new firewall from 6mm plywood (if it's a .40-.60 model).
Do use Ca glue (thin and medium and of course acellerator) not Epoxy which is heavy and slow to use and doesn't bind to an oily surface that well.

Regards!
Jan K
Sweden

No one seems to mention anything about the fuselage damage? Would gluing a balsa strip to the side next to the break be enough? or should I build the whole side from scratch?