Nexa Twin Otter Rebuild

The Twin Otter has been out of stock for sometime so when I was aware of someone selling one built but unflown I went for it. However, on collecting it I was wondering whether to take it or not as it had a fair bit of hangar rash and did appear not to be assembled very well. Sometimes being a bit "dumb" I bought it anyway as a project rather than walk away or insulting the really nice old feller who had been through some recent bad medical times. Although this maybe the second time I have made a dumb decision and bought a model and had to rebuild it. A Carl Goldberg Super Chipmunk back in 2012 comes to mind and it ended up in the back of the garage for another 6 years. It did fly well in the end after a revamp until a mid air with Simon O's foamy Wot 4.

Right let's get down to it - The fuselage was not badly put together but the control rods for the elevator and rudder could do with being re-routed. The wings though were something else. :ohmy: The Turngiy 85 amp Plush ESCs were taped into the nacelle with a bit of insulating tape. The motors were those heavy in-runners usually fitted in EDFs. They were mounted to some 3mm ply that was epoxied into the cowls (see image). The cowls are secured by tiny little black screws as would be expected. The motors would have probably have pulled the cowls straight off on first throttle. Oh dear! The firewalls had been hacked to death to clear the back end of the motor..

Re-make these firewalls and clean up the cowls? Motion RC had the cowls in-stock but no firewalls. Oh, well I will take the cowls and sort out the firewalls myself - maybe...The firewall assemblies appeared to have been inserted and well glued in, so my only option was to cut the motor mounting away from the firewall assembly. First job was to get a template of the motor mounting. Using my Parkside disc cutter alongside each of the insert lugs and picking away at any white "glue" found and gradually levered the mountings away.

Using the template and the bits of mounting I copied the shape four times on to 3mm ply. I cut and sanded the ply into the oval shape until all four pieces were indentical. I used one of the cowls to assist in getting the right shape and that the cowls actually will now slide over the mounts. With the four pieces I glued them together to make two 6mm mounting.On Sunday with no rain forecast I was back out in the drive and recreated "some" of the slots to refit the mountings to the firewall assemblies. Where some lugs could not be made I would use fillets on the inner sides. The 5 minute epoxy in the temperatures we have had present meant I had to work real fast to fit the mounts after the normal dry fit check.:lol: With that done I will wait till the new cowls arrive today or tomorrow via FedEx to verify if they slide over nicely the mounts or may need a bit more sanding. Then clean up the front faces and repaint the mounts in matt black

Can't be easy with so little of the original ply parts remaining, the firewalls and formers looked as thought they'd been attacked by some wood eating creature.
Looking forward to the next bit, want to see how you align the motor mounts.

Brian Jackson wrote:

Can't be easy with so little of the original ply parts remaining, the firewalls and formers looked as thought they'd been attacked by some wood eating creature.
.

No Brian its an DHC Otter not a Beaver :woohoo:

Brian, most of the lugs I managed to keep intact so therefore the firewall mounting when up tight against them would enable re-alignment. Thanks FedEX, did not turn up yesterday with the Cowls. I thought it was too good to be true because tracking said they were in Roissy, Paris.
The wood eating creature was human which is very concerning for those of us with wooden aircraft. :ohmy:

Oh god what have I let myself in for? The covering on the wings has to come off due to random holes made by wood eater. I assume to pull servo leads through although totally unnecessary. None of the servos were identical.:huh: and were old Futaba stuff, well the ones I can see the label on. The printed covering I found out is self adhesive (wtf) which is why on doing a test shrink earlier it did not shrink tight.

Took a while to strip it off, the inner side had loads of bits of balsa and other foreign objects stuck to the sticky surface too. I reckon on two rolls of the nearest yellow will be Oracover Cadmium Yellow. Here is the worst bit! Price gone up from £18.50 when I last bought some to £26.75.:huh: This is getting an expensive rebuild. One of the wing ailerons is not fitted correctly so this means cutting the mylar hinges and replacing with Robart flat pin hinges. At least with the ailerons off it will be easier to re-cover the wings.

Ding dong. FedEx at door with the cowls. Merci beaucoup!

Have a look at the covering offered by 4Max Phil. Under £20 for 5 metres. I feel your pain with the "Blue Peter Sticky Backed Plastic". I had a Seagull low wing model covered in what seemed to be very thin lino. Wouldn't shrink, split at the drop of a (very light) hat, and weighed a ton due to the generous coating of Oriental Evo-Stik. Ghastly stuff.

I think Rapid RC sell a lot of H/King stuff including their covering film which one avid WMAC builder has used with good results

www.rapidrcmodels.com/rapid-rc-cover-film-282-c.asp

I have ordered two rolls of Macgregor covering for the price of one Oracover. A member says their stuff is good. Will soon find out.

No work today on the Twotter as Cashmoor beckoned. Waiting on covering. Firewalls were sanded last night a bit more to ensure the cowls are a sliding fit over the nacelle covers. Slightly off subject but two members have recently bought a Focke Wolf and P51B from same manufacturer of the Twotter, VQ aka Nexus and others. They look nice with all the details (printed) but God help them if they have to repair them. They are sticky back too apparently.