Fokker F.VIIa

[marcin_pl]

What is a thickness of the LE sheeting?

Marcin

[Stunthenk]

About 0,6 mm. I started with a 1 mm sheet that weighed 9 grams (standard size, 1 meter by 10 cm. so a density of 0,9). After applying the sheeting I did some more carefull sanding at the spar and the LE so now it is anybody's guess!

[OZPAF]

Nice work Stunthenk! Your use of bamboo is interesting.

John

[Stunthenk]

With a model like the F.VII construction goes along fine, untill you get to the dreaded exposed engine. Then all momentum disappears.... That's the reason why this update took a while. First you have to design your model engine. In this case the engine is a Bristol Jupiter VIIIF, a 9 cylinder single row radial engine with a front exhaust collector / silencer. According to my enlarged 3-view the diameter should be approx. 36 mm. I therefore decided the diameter of the crankcase to be 18 mm, leaving 9 mm for each cylinder assembly. Perhaps scalewise the crankcase should be smaller. But in the model it is also the noseblock so it needs to be sufficiently sized. The cylinders have a part with slightly larger cooling fins under the head. The cylinder head has exposed rocker arms and valves. Each cylinder has two exhaust ports, with a Y shaped pipe connecting to the exhaust collector. The collector has two exhaust pipes going to the rear of the motor.
In the first picture you see the noseblock / crankcase in he model, a test cylinder and 9 cylinder stubs on a stick board between two supporting sticks to be sanded down to the correct size. Nine thinner, larger diameter stubs are wainting their turn on the sticky board to be sanded; and 9 3 mm balsa oblongs are waiting to be turned into cylinder heads.
In the second picture you see 9 cylinders under construction, the exhaust collector and the test cylinder.

[dputt7]

Great to see this amount of detail. Good luck with the rest.

[TheLurker]

With a model like the F.VII construction goes along fine, untill you get to the dreaded exposed engine. Then all momentum disappears....

Aye.  You have my heartfelt sympathy.

However, I'm in complete agreement with Dave; the level of detail is very impressive.

[Stunthenk]

Thank you very much, kind gentlemen, but in my opinion this is simple balsa bashing and not comparable to the efforts of the real experts. Just look at pictures from Walsall and Wychen models and you know what I mean! And I still try to figure out how to do the Y shaped exhaust pipes? (And of course, I HAD to do an airplane flown BEFORE the introduction of NACA style cowlings....)

[TheLurker]

...still try to figure out how to do the Y shaped exhaust pipes?

Henk, if the exhaust stubs aren't too small to work with might something like the sketch below work?  Make the Y joint in basswood/bamboo and then paper tube extensions into the Townend ring and the cylinders.