Nov 10, 2012, 03:09 PM
Entropy is happening!
Jim.Thompson's Avatar

Work re-commenced at last!

I have finally got back to the Wompoo project!
The first thing I had to do, was clear my bench which was cluttered from weeks of neglect and small maintenance jobs etc. The first pic reveals the mess. Twenty minutes later, and it was clear and I was ready to start work on the cores for the tail plugs.
Pictures will tell much of the story. The masonite templates for the tip curves ensure a fairly smooth curve. These have the wing tip curves on one corner and the tail tip curves on the opposite ones. I use this little hot wire bow for the cutting, which was made up from a mini-hacksaw frame and some short left over stainless fishing trace.
After the hot wire cutting, some light sanding is required to smooth them out.
Then I mark the extent that the tip sanding should go to. Needless to say, the tips are thinned progressively as the effective chord diminishes towards the tip.
The CNC cutting experts will probably blanch at this handwork which is done only by eye and judgement, but I figure it will be fairly good. I hold the tip up to the light and rotate it to check the profile and sand as necessary. Then I hold each one up tip to tip and rotate and check for any visually obvious lack of symmetry. More sanding as required etc.

I have cut the glass required for vacuum bagging and plan to do that today.


edit: The titles to each picture did not show. I don't know why? Anyone know?
Last edited by Jim.Thompson; Nov 10, 2012 at 03:11 PM. Reason: see edit.
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Nov 10, 2012, 04:22 PM
Auzzie built planks
timbuck's Avatar
Glad to see your over the dreaded lurgy.. Mate. AND if you call first pic a mess...
Your not trying hard enough.

Latest blog entry: More colours
Nov 10, 2012, 05:42 PM
Entropy is happening!
Jim.Thompson's Avatar

Root Ribs.

Thanks Tim!

I was just about to layup some glass cloth to make some 3mm thick flat glass/epoxy stock to make the root ribs for the tail plugs when I realised that the 3mm thick laminating bench top plastic that I have in stock just might do the job.
So I have done a little adhesion test with some epoxy. If it sticks ok, it will do the job nicely.
I plan to glue on onto the foam cores before bagging to provide a nice flat and square root and to control any tendency the foam might otherwise have to crush slightly at the root.
Two other root ribs will be cut to make stubs to glue to the fuse plug onto which a small fairing will be shaped. I have to take care with the fairing on the top side of these stubs to avoid negative draft angle in the moulds! In other words, to ensure that the plugs will actually come out of the mould.


I just remembered that I have used this laminate with epoxy before, so I can go ahead! Getting old and forgetfull!
Nov 12, 2012, 12:26 AM
Entropy is happening!
Jim.Thompson's Avatar

Glass/epoxy tubes.

I had to make up some new tubes to suit the 3 mm carbon rod that I plan to use to retain the tail surfaces.
Also, I had to cut some new root ribs due to a slight stuff up. The joiners and tubes have to be staggered to fit in the fuselage. ie.: one pair slightly forward of the other pair (two for each tail surface). I spaced them apart without the tubes included, which mean they then would be too close. So I'm making two more, and will space the holes to take into account the mating tubes.

I made up the tube by first of all waxing the 3 mm carbon rod. Then I cut some drop sheet plastic into a long strip about 20mm wide. This was taped on one end of the rod with a tiny piece of tape and then spiral wound onto the length of the rod required. Then I passed some 1/4 inch glass biaxial sleeving (from Soller Composites - very nice, but costly!), over the rod. It was tensioned up and then wet out.
The next day, I slid the rod out and carefully removed the tape at the starting point, and then twisted and pulled it out.
It worked very well, however, the clearance is a bit large. Perhaps I can brush the rod with epoxy to enlarge it slightly, or pull something through the tube to wet out the inside of it to reduce it. Probably safer to do the former.
Any suggestions?

Nov 12, 2012, 03:21 AM
chetosmachine's Avatar
Originally Posted by Jimbello View Post
edit: The titles to each picture did not show. I don't know why? Anyone know?
They do show when you click them and see fullsize
Nov 12, 2012, 04:25 AM
I'm All Thumbs
AirBornOne's Avatar
Originally Posted by Jimbello View Post
I have finally got back to the Wompoo project!

edit: The titles to each picture did not show. I don't know why? Anyone know?
Forgot to save changes?
Nov 12, 2012, 02:36 PM
Entropy is happening!
Jim.Thompson's Avatar
Originally Posted by AirBornOne View Post
Forgot to save changes?
Ahh! Very likely.


They don't show on my computer? Mysterious.
Nov 12, 2012, 03:11 PM
Entropy is happening!
Jim.Thompson's Avatar

Root ribs.

I've printed out some more root rib profiles on my computer using Profili2 and pasted on some laminate ready for cutting out.

(I have saved changes this time).
Nov 12, 2012, 08:29 PM
Entropy is happening!
Jim.Thompson's Avatar
I have decided to have another go at making a tighter fitting glass tube.
I will also put some resin through the one I've already made.

Meanwhile, I'm cutting out the root ribs this afternoon. It's such a relief and pleasure to get back to work on this after such a long delay!!
Nov 15, 2012, 10:57 PM
Entropy is happening!
Jim.Thompson's Avatar


I did some final work on the decalage correction and now have it as I want it.
I was not happy with it the way it was. I'm content now to continue on with the fuselage finishing.
To correct the angle, I used my jig saw to cut slots along the fuselage and down the front of the wing. This allowed the wing with the fillets included, to be raised at the LE compared to the TE. I can explain this more later, if this is not clear.
All that remained was to glue and reinforce the joins again. I did this first with CA and then reinforced it inside to as far aft as I could gain access. To do this, I cut a square section out of the fuse just in front of the wing. After some glass joiner "tape" was applied inside, I simply glued an new piece of pre-made fibreglass over the removed section. Next step with this is to begin splooge filling, shaping and sanding. Then primer etc. etc.

My second attempt at making some glass tube (2.5mm, not 3.0mm as previously posted), was much more successful. It was a bit harder to remove off the mandrel, but is a close clearance fit. This time I wound the drop sheet plastic sheet tighter and also stretched the biaxial wet out glass sleaving by hanging a weight on one end and taping the other to the mandrel. I have made sleeves of several sizes and can much recommend the ready made sleeving for this job.

I also have the root ribs glued on with spray adhesive, then a thin cardboard strip, and finally the part ribs that will form the basis of the fuselage to tail surface fairing. The plan is that the cardboad will assist me to cut through it with a hacksaw between the two plastic laminate ribs to achieve a nice flat/square pair of surfaces when the one piece plug is cut up into five separate pieces.

Last edited by Jim.Thompson; Nov 15, 2012 at 11:00 PM. Reason: grammar/syntax correction.
Nov 16, 2012, 05:47 PM
608 km/h!
josh18's Avatar
Nice one Jim, glad to see youre back at it. I reckon that fuse would look just right with a small cockpit bulge just over the wing.
Cheers mate
Nov 18, 2012, 06:12 PM
Entropy is happening!
Jim.Thompson's Avatar
Thanks for the encouragement and the suggestion for the cockpit Josh. It may look ok, but I'm going to stick with the purist "freestyle" look this time.

I have bagged the tails at last and pulled them out of the mylars this morning. They look good. Vastly superior to the first ones.

I've also been working on the fuse/wing assembly, particularly the fillets. To give the reader and impression of the size of the wing fillets, I am using the top of a rattle paint can as my guide and splooge screed. They are coming up quite good and will require some more filling and sanding of course.

I am almost ready to set up my old "V" tail alignment jig and drill some holes to take the pins and tubes for the tails, then fit them.

Progress happens!
Nov 21, 2012, 09:45 PM
Entropy is happening!
Jim.Thompson's Avatar

Final prep for tails.

I've been fitting the 4x2.5mm tubes to the tail surfaces. They have to stagger of course, and I made up a simple jig to ensure that each pair would clear the pair on the opposite side when inserted into the fuse plug.
While the glue was curing I set up my old "V" tail jig. See pics.

Ready now to drill holes in the fuse to take the alignment tubes and pins.

Nov 22, 2012, 02:18 AM
Entropy is happening!
Jim.Thompson's Avatar

Tails fitted!

Tails are now glued to the fuse.
Nov 22, 2012, 09:04 AM
Registered User
Nice jig!

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