Avro 504 N/O 1/20th scale electric

[g_kandylakis]

Thanks Jeremy, Stephen.

I hope the delay in continuing posting only helped build up some more anticipation 

So, what comes next after covering? Why, stitching and rib tapes, of course...

For the stiching I built a simple balsa frame and glues a piec of tissue. Shrunk and doped, then thread was passed over it in parallel passes, the distance between passes defined by two rows of pins. In each row the pins are about 2,5mm apart from each other = the distance between individual stiches on the real plane divided by the scale.

With the thread ends secured, the thread passes were glued to the tissue, using white glue. Enough passes to make sure a strong bond has been achieved, this is most important to avoid dissappointments later on. White glue was chosen because it is not affected by dope and thinners that come later.

Mike ZK-AUD has suggested in the old HPA to attach the tissue to a cylinder and wrap the thread passes over the tissue, with the obvious advantage that the thread would be tight on th tissue and would be easier to glue. I agree, alothough I did not try it, so I am mentioning it here as an alternative.

Nest step is to slice the released tissue-thread  part in thin strips. I use my small micrometer adjustable base. The width correspond to the rib thickness, more or less. The Avro had ribs of various thicknesses, so these were cut. Plenty of them given it is a biplane with many ribs...

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lots of strips...

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Next comes the first fun part.

Glueing individual strips onto the ribs. Glue one end first, let dry and then pull and glue all along the strip. When dry, cut off the excess ends.

Continue to the next rib, then to the other side, then to the other wings...

Great fun 

I use thinner for attaching, it softens the dope on the wing covering (did I mention int already had two coats of dope? no I didn't) and the dope on the strip.

And here is the first test of how strongly the thread was glued to the base tissue. There is nothing worse than tiny 0,7mm long thread pieces suddenly flying away from the glued strip.

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stabiliser halfs and rudder being shrunk and then doped. Fixed on the board while drying

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So, at some points all the parts have their rib tape strips glued on.

I chose yellow for the tissue on purpose, to contrast with the white covering while gkueing, for easier alignment. The strip should sit over the rib, of course...

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Rib tapes are next.

Again, a simple piece of tissue, not doped this time is cut in 3mm strips, using the same micrometer adjustable cutting base.

Fun part #2.
Each rib tape is given a coat of dope, then placed over the rib stich strips and some thinner with a thin paintbrush.

The secret here is to press the rib tape onto the wing so that there are no "air pockets" or gaps between them. For best results I use a block of very soft balsa, to press the rib tape. The balsa is soft enough for each protruding rib stich to push through and allow the rest of the tape to be pressured.

I hope my description on that is adequate.

And that is that! An extra coat of thinned dope can be given, to seal everything together.

[gravitywell]

Simply amazing!  My eyes would be bugged out of my sockets trying to do that kind of work!

[g_kandylakis]

Thanks Glenn,

to be clear, of course I use a large magnifying lamp while building. Impossible to do otherwise.

Back  to the struts, the end plates have been bent and glued to each strut, doublechecking the type and orientation. In the end all 12 of them are different.

Thin paper was rolled at the strut ends to simulate the socket

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Three light coats of wood exterior varnish brushed on, give a very nice finish

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Tailskid, made of thin brass tubing.

Not the lightest choice for the rear section, but the only way to arrive at a delicate, yet strong enough, scale like structure.

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Tail section showing the spring for the tail skid suspension.

And start of the fuselage covering, top curved deckings first

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After the top decking was covered, it was time to add the cockpit coaming. Made of pink foam, roughly shaped first and then glued on with white glue.

The groove is for proper positioning on the top decking and to hide the balsa ends afterwards

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to achieve a uniform overhang distance from the top decking, a balsa spacer was used to trim/sand the excess foam.

Next it was sanded round and pressed where the coaming stitching would be.

Finally it was sealed with thinned down white glue to a smooth finish for painting.

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Open cockpit means the wood structure is visible through the cockpits, so this area was given some brown varnish too.

Next came the covering of the sides, the rear top fuselage and the bottom

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So, that would mean the fuselage is finished. Normally. But there is some debate as to what normal is. Or how normal the builder was when he was building this...

Another surface texture detail that stuck to my head was the fuselage lacing. Having a clear 3D texture, I was not satisfied with simply simulating it by paint or leaving it out altogether.

So (the madness begins) first I measured from photogrqaphs the aproximate pitch of the lacing pins and drew the lacing paterns.