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Top Flite SchoolMaster Scratch Build: Log

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Old 08-12-2013, 07:25 AM
  #1
yashodhanp
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Default Top Flite SchoolMaster Scratch Build: Log

Hey guys, i started work on a Top Flite SchoolMaster. I decided to use only Japonica aka Japanese Cedar because of its low cost on ready availability in India.
Japonica is around 1.5 - 2 times heavier than balsa and slightly brittle.
It can be cut using a 'Box Cutter' or a fine tooth 'Hack Saw'.( Hobby Knife NOT recommended)
I spent around INR 500 ( $ 8-9 ) on the wood for the entire model.


I made a few modifications to the actual plans:
1. D - Tube Construction instead of a Fully Sheeted wing
2. Addition of two Spars to the ribs to impart a bit more strength.
3. Conversion to electric
4. Using solid Japonica for the Horizontal Stabilizer instead of a sheeted construction.


Build Log :-


Fuselage.
Started of by sticking additional strips of japonica to the main sheets to get the correct width of the fuselage.



Rough cut the fuselage sides using a hacksaw for sanding into shape





Added a template cut from plans to the pinned together sides for final sanding of the Fuse



Thought of cutting out lightening holes but didnt proceed with it


Final Result of the sides



Sorry no pictures of the actual fuselage build. Was too engrossed in building the fuselage and forgot about pictures
Applying top and bottom sheeting (Had to apply Elastic Bands to hold the sheets in place due to the low flexibility of Japonica



Final pics of the fuselage (Currently fit with an E Max 2215/09 Motor with 10 x 4.7 Prop)



Wing:
The Wing was where the most number of changes were made because it was fully sheeted,which I converted to a D Tube style construction.

Basic assembly (Sorry For the Poor Quality of the Pics)


After Application of the Sheeting and Cap Strips


I shall be using 4mm Carbon Fiber tubes Epoxied into place as the wing joiners. (6mm x 6mm Spars were used)

and covering of the model shall be done using Polyester Film that is adhered onto the wood using contact adhesive and shrunk using a normal household Iron.

The Covering Material I shall be using. Will paint over it using Enamel Paints to a Nice Colour Scheme after the first test flight.\

Horizontal and Vertical Stabilizers coming soon

Pls. feel free to comment on the Model, and how the build is coming along. I am open to suggestion, criticism etc.
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Old 08-13-2013, 03:30 AM
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Old 09-02-2013, 06:25 PM
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Old 09-08-2013, 04:12 PM
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Old 11-21-2013, 02:14 PM
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John in Boston
 
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Hi there! Interesting to see this now-classic Ken Willard design under construction in 2013!
The Schoolmaster was one of my first truly "big and complex" model kits I built as a youngster in the 1960's.... unfortunately my memories are dim about it ... I am not even sure if I ever finished building the kit.

How is your progress? The use of Japanese cedar as a low-cost and available alternative is interesting. Best wishes to you.
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Old 11-22-2013, 05:04 PM
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I taught myself to fly with a Schoolmaster and liked it so well I scratch built another one. The second weighed only 16 oz complete with .049 and radio and was amazing in flight. But the heavier one flew very well too.

Very interesting to use a different wood. Hope it works well for you. Jim
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Old 11-23-2013, 07:59 AM
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John in Boston
 
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Yashodhan, one suggestion: Watch the weight!

If the Japanese Cedar is THAT much heavier than balsa, be careful. The Schoolmaster is a small model, so you need to be especially vigilant about her weight.

Do everything you can to reduce her wing loading, so the model (and you) will not suffer when she is trying to fly!

Avoid "over-engineering" and "over-building" the remaining structures; do not paint the model; use lightweight landing gear and wheels (or none, at least for the test flights?); use the lightest radio components and motor; ...what else am I not thinking of here?

As my father always lectured us: "Weight is the enemy of all flying things!"

Last edited by John in Boston; 11-23-2013 at 08:23 AM.
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