c182
Leading Aircraftman
Posts: 4
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Post by c182 on Aug 19, 2016 8:37:31 GMT 12
Craig, talk to Pete, he has a fluting machine at Phoenix
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Post by baronbeeza on Aug 19, 2016 10:03:10 GMT 12
I haven't tried rolling flutes into 2024 but at T3 it is difficult to work. I assumed the rolling would be done in 'O' state and then heat treated back to strength. Some of those flutes had compound curves also so that is going to complicate things. 2024-T3 is not going to be malleable like perhaps aluminium or mild steel. Safe would have the capability but for local manufacture there are going to be a number of requirements that will need to be met. Having the material spec and thickness will be essential and by having samples you should be ok there also.  |
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Post by Mustang51 on Aug 19, 2016 11:27:49 GMT 12
Trying to work in T3 not so good.......... "O" condition the only way to go and heat treatment to T3 should be available over there. I did manufactured some bulkhead parts for my Birdog in "O" and had QANTAS do the heat treatment for me. Perhaps Air NZ have a facility?
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Post by craig on Aug 19, 2016 11:50:39 GMT 12
Craig, talk to Pete, he has a fluting machine at Phoenix That would be too easy! unfortunately not the correct shape. The flutes along the front terminate before the edge and the skin is then able to lap under the leading edge skin. Visible in the far right end of photo. |
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gtw
Flight Lieutenant
Posts: 85
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Post by gtw on Aug 19, 2016 12:28:50 GMT 12
Hi Craig. It was 1970 when I had a cropmaster / I seem to remember being told to look after the tail plane as the skins came from the rudder/fin of a piper. Hard to get 2nd hand.
Have fun George
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Post by lowandslow on Aug 19, 2016 19:05:02 GMT 12
Heat Treatments in AA harden 2024. Trevor Parkers grand champion homebuilt Pazmany PL2 was all done in T0 then hardened at Heat Treatments I believe. I am a toolmaker and a simple form tool could easily form these skins in T0. They will distort a little bit but running through the form tool again should straighten them out.
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Post by madmax on Aug 21, 2016 16:58:34 GMT 12
The empennage of the first five YA-1 Cropmasters were wooden units from original CA-6 Wackett trainers however the Australian DCA banned them when it was discovered that agricultural chemicals were affecting the glued joints. The metal "stabilator" fitted to later Cropmasters were copied from the Piper Comanche, however while their dimensions were identical to those of the Comanche their construction was much simplified. I'm unsure it the fin and rudder were Comanche copies.
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Post by craig on Sept 20, 2016 10:27:17 GMT 12
Have started on the RH fuel tank. Made of fibreglass they essentially hang off a panel which inserts into the top of the wing. This is one of the components which is taken directly off the Wackett. So at best new sometime in the early 40"s   The supporting panel which forms part of the top wing skin consists of two skins. The outer flat skin and a ribbed support skin below. The 2 skins are riveted together to form one unit.  Saddles are attached to the inner skin to support the top of the tank which is in turn held in place with straps. As you can see one of the saddles is beyond repair. Fortunately I have a number of spare panels in varying degrees of disrepair and I was able to salvage a replacement. Everything is deriveted for cleaning and repair. The tank itself is constructed from fibreglass (suprising for 1940's technology?) and has 3 openings. Fuel gauge (direct reading), filler and outlet. All these need removed, cleaned and prepared for reassembly.    The screws holding these fittings in place are 2BA for the filler and gauge and 1/4 BSF for the outlet. The 1/4 BSF are proving to be hard to obtain in Cheese head with lock wire holes drilled. I have got some allen type heads ordered which will require lock wire holes drilled. Alternatively could clean the originals and have them recoated. |
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Post by craig on Sept 20, 2016 13:07:49 GMT 12
Photo of cleaned fittings  |
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Post by Mustang51 on Sept 20, 2016 13:08:21 GMT 12
Clean the originals. I've done that many times with the Birdog although that hardware is far, far easier to find.
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Post by isc on Sept 20, 2016 22:15:43 GMT 12
At least with the Birdog it uses AN fittings, why on earth did the Aussies go with BA and BSF. I suppose there would be heaps of red tape to change threads from the original specs. isc
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Post by craig on Sept 21, 2016 6:33:11 GMT 12
The backing plates which go inside the tank are cast alloy (there are a couple visible in that last photo) so changing to UNF would require adjustments. 2BA are still fairly available and even the BSF is OK in the common head types, just not cheese head especially drilled.
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Post by craig on Sept 23, 2016 7:16:32 GMT 12
Flaps complete  |
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Post by isc on Sept 23, 2016 22:36:01 GMT 12
From what I'v seen, the museum at Wigram has about the biggest collection of BA fittings, nuts bolts, turnbuckles, although I imagine they have used a good many since I last looked.
If you need BA taps, and dies, or BA bolts(not spec), you can get them at Drills Taps & Dies, Unit 2 25 Green Lane Sockburn Chch. Not cheap, needed some 7BA for a Stuart Turner S9 steam engine that I built the other year. isc
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Post by Mustang51 on Sept 26, 2016 10:45:42 GMT 12
Why did we Aussies go the BA route............... It's British Sir ! And isn't BA based on a French thread? Thought I read that somewhere.... early pioneering days of aviation and all that.
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Post by isc on Sept 26, 2016 20:50:15 GMT 12
BA is based on Thury a Swiss instrument makers thread, I think the biggest users are model engineers working to British model plans, many of which are quite old. Done (and do) a bit of it myself, but usually steer clear of BA, unless I'm restoring an old model, for example a Stuart Turner S9 steam engine. isc
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Post by baronbeeza on Sept 26, 2016 21:11:42 GMT 12
I have struck BA screws in common usage in electrical equipment and I recall them on the Tiger Moth also. While I didn't see any personally at Ohakea I know of an individual that went by the nickname 12BA, something to do with the smallest screw on Base. From my experience I would have thought something around 2BA being the more common size. en.wikipedia.org/wiki/British_Association_screw_threads |
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Post by craig on Nov 2, 2016 5:33:55 GMT 12
Final fix leading edge  |
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Post by Mustang51 on Nov 2, 2016 7:48:36 GMT 12
Looking good. That is a mammoth task. Now to do that on my Birdog port wing!
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Post by craig on Nov 9, 2016 21:06:09 GMT 12
LH flap attached and fits perfectly.  |
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