Rebuild Thread - EF 104 Extra

Been working on this for a few weeks but not got round to posting anything, should make a change form build and ARTF assembly treads hopefully.

Last Summer my Extra went in for still unexplained reasons 2 fields away at the far side of a rolling circle during IMAC practice. It has been sitting in the garage looking sad for a while but repairs are now underway.

This is what it looked like after recovery, front end destroyed left wing badly damaged and right wing minor damage.

I have ordered and received a new cowl and wing tube but other parts were either not available or to expensive to be worthwhile.

So starting with the fuselage, the engine box was destroyed and cowl mount bulkhead (F2) badly damaged, I removed the damaged engine box and cut right back to the undamaged ply far enough back that I felt confident of getting a secure fixing fro the new engine box. Thanks to typical ARTF construction using hot glue, it was reasonably easy to break the joints and leave the original ply tabs on the internal formers.

Next job, which took an age, using a combination of a reciprocating saw, chain drilling and many scalpel blades, I remade the damaged parts using 2mm birch ply, 2 layers laminated for the sides, top and bottom of the engine box and 3 layers for the front bulkhead.

I used the original damaged parts reassembled jigsaw style as far as possible and checking with dimensions supplied by a friend who also has one, very time consuming, but the results were very good.

After many hours, I ended up with a full set of parts, originals and new photos below

Then the parts assembly, as I had managed to preserve the locating tabs in the existing parts and cut tabs and slots in the new parts as the original design, it all locked together really well, it took a fair amount of trimming and filing but I am really pleased with the result, even when test assembled without glue it felt really strong.

Sides going in, when laminating the 2 layers I created an overlap at the joint between old and new parts to ensure it maintained the original integrity.

Sides and F2 installed

Then the rest of the parts are added

You have certainly done some time consuming work. I believe you need to have certain mind set before you start a major fiddle-ass job. so easy to say "can't be arsed". Well done Jon.

Finally, I added lots of balsa triangular stock to reinforce.

Just need to fuel proof and this is now finished, next job is to strip the bottom covering off and check that all if the other joints are secure and to add glue or reinforcement as necessary, then on to the wings.

I will try to keep updating as I go from now on.

PhilF51 wrote: You have certainly done some time consuming work. I believe you need to have certain mind set before you start a major fiddle-ass job. so easy to say "can't be arsed". Well done Jon.

Thanks Phil

To be honest, it has given me something to do on these terrible wet and windy weekends!!

Great job! Well impressed!