|Mar 06, 2010, 11:37 AM|
I decided to build a smaller and modified version of Guppy model, for the slopes.
It is GUPPY MicroSloper
Wing span: 120cm (~47")
Wing area: 13,4 dm2 (~207 sq")
Length: 69 cm (~27")
Controls: aileron, elevator
Description of construction:
Wing will be made from balsa. First third of the chord will be carved from solid hard balsa and rest is allmost "normal" design... fat ribs, rear "spar" and solid balsa triangular section balsa ailerons.
Wing with shallow dihedral, maintained with plywood inserts at root.
Fuselage is of "pod and boom" type. Boom is ordinary carbon tube 6/4mm.
Pod is a plywood structure. It takes all the beating, while outer skin made from wacuum baged plastic is just for the shape.
Vertical tail is a strong structure, made from thin plywood skin and some plywood internals. There is a bracket inside the fin at its rood, that helps tto transfer elevator servo pushrods movements upright to the elevator itself.
As model is rather small, simple bended pushrod ( as found on older Guppy and Guppy 2) will produce excesive friction and allow some freeplay on teh elevator. We dont want freeplay on the fast flying slope glider.
Horizontal tail is made from solid balsa sheet. It concict some parts with different grain orientation in order to be stiff in torsion..warping free elevator.
O.K., enough of talking, let see the building of the model!
Computer rendering of the initial design.
Computer rendering, shown basic parts of the glider.
Testing the solid balsa carving:
Initial test...not yet the proper foil section....
Result of testing proper tool. Upper surface made by a tool, bottom surface sanded by hand.
Fuselage basic structure assembly...
Fuselage sides glued to the rear part and main former.
Front end formers...belly up view.
Tail boom placement (temporary inserted.. it will be glued later in the assembly process)
Basic fuselage structure finished. Testing of the RC equipment to fit....
Front fuselage part plug.. making :
Hardwood blanks with a fuselage template.
Cutting on the bandsaw.
Smoothing out on the bandsander.
Bandsawing the sides of the plug.
Sanded on all four surfaces.
Rounded edges, and sanded.
The canopy cover and side fuselage shells will be vacuum baged, but as I have not yet made wacbag box, I decided to test my plug using well prooven plastic bottlemethod for making test parts.
First I made a blue canopy:
Test canopy made.
Then I made a piece of side shell. It came out shorter, as the bottle was not large enough. But for the test of plug and test fit of the shell to the basic fuselage structure, it was enough.
Fuselage shell. Fits well.
Well, so much for my first post in this new story.
|Mar 06, 2010, 07:32 PM|
Looks like something from a bygone era........long long ago when people actually LIKED building planes!
still likes building...
|Mar 07, 2010, 07:46 AM|
The problem is, that model is designed in such way, that needs some unique DIY tools and accessories to build, that`s why it is a little unsuitable for the pure scratchbuilders. So, no use of offering plans.
This way of design allow me to build fast and acurate (hopefuly ) using adapted tools, jigs and so on...
Today I recieved 3 heaters (300W each) from my friend, so I can start thinking of a vacuum baging machine.
I am also starting wit assembly of the firm bench for a router tool for carving the leading edge of the wing.
Tomorrow I will probably purchase some plastic sheet to have something to play with..
|Mar 07, 2010, 09:50 AM|
Thats going to be a nice little plane Mitja.
I'm interested in how you're making the fuz, you've made a plug and you mention vac bagging, are you planning on making two halves and then joining?
|Mar 07, 2010, 01:07 PM|
|Mar 07, 2010, 02:30 PM|
Should be a fun plane. I built an original version of the motor glider Guppy and enjoyed flying it until a radio glitch took it into the Pacific. Amazing how fast a LiPo get hot in salt water!
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