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Sabre F-86A (FlyFly kit) video

Test flight of my F-86A Sabre equipped with EPF Hobby electric retractable landing gear
The model is built from a Fly Fly foam  kit that I covered with glass cloth and epoxy resin for a better finish and durability (at the cost of a higher weight in flight).
As the airframe is made of polystyrene foam, it was out of question to use solvent based paints. So I used Tamiya paint to finish the model. I especially like the rendering of aluminum Tamiya gives, although it is sometimes difficult to get a smooth finish when it's airbrushed. but smoothing each coat with 400 grit  sandpaper provides a realistic and convincing surface finsih.
I used the booklet "Walk Around n ° 21 F86 Sabre" published by Squadron Signal to make the paint scheme. It contains several interesting profile views for anyone who wants to make a custom paint scheme for his/her model.
The FlyFly air retracts caused me a lot of trouble.They are  spring air  single action type. This means that the air pressure keeps the landing gear up and a spring provokes the descent of the gears when there is no more air pressure into the cylinders. This system is reliable and efficient if it's well built. Unfortunately the FlyFly retracts leak, the springs are too soft to ensure reliable locking aso. Finally the thread that held the air cylinder on the nose retract  snapped on the first landing!
Tired of battling with this thing, I decided to mount EPF Hobby electric retracts.The installation of this retracts does not pose any particular problem, with the exception of the front wheel. You must indeed be a bit inventive to accommodate the steering servo forward!
The video presented here shows the first flight of the Sabre with its new retracts.  It weighs 3kg AUW which is heavier than if you fly the crude polystyrene model out of its box!
Yet given the size of this plane, 3kg is very reasonable. The Wemotec Midifan running on 6S takes it all in without any problem, at low speed the Sabre floats in the air and landing is just a piece of cake.


Full article on the construction of the Fly Fly F-86 Sabre

 
CNC - Introduction Print E-mail

CNC What does it means?

cnc_vue_01.jpgCNC is an acronym for "Computer Numerical Control". It means that a machine tool like a lathe or a milling machine for example, is controlled by a computer to perform a series of operations. If this kind of equipement is quite common in the industry, it was highly unthinkable to build or buy such a machine for hobby usage just a few years ago. Then a handful of ingenious guys started to play around and made the path easier for everybody.

A CNC to do what?

Before I build a new model, I always draw the plans in a CAD program.

It's relly good to use the precision of a computerized drawing. But why bother with computers if you then cut the pieces with a jig-saw or by hand? The CNC milling machine is the solution. Directly controlled by the computer, you get a stunningly precise result, and you can reproduce the same piece over and over again. Say goodbye to the cutter, blocks of ribs and badly cut pieces using the jig-saw.

Models and site references:

I did not invent anything (or not too much anyway) to build my machine. You find lots of information and amateur creations on the Internet. Most of them are inspired by the model done by Guillaume Coquery. He's found simple and workable solutions which doesn't cost a fortune. These solutions let you build a machine with almost professional performance. He has also written a very good software to control the milling machine. If you want to build your own cnc milling machine, a visit to his site is a must http://g.coquery.free.fr
The aeromaniacs site and the cnc25 mailing list are very useful when you start such a project. The members on the mailing list answered many of the questions that came up during the design and construction of my machine. The machines made by Thierry Monnot and Jean-François Delhove are also really good creations that are worth studying before starting.

Technical specifications of the model presented:

Size:

1210 x 765 mm

Vue perspective de la machine cnc

Working area (mm):

800 (X axis) x 350 (Y axis) x 80 (Z axis)

Stepper motors:

Sanyo Denki. 5 volts 1 amp/phase unipolar 200 steps/round

Power supply:

13.8 volts 20 ampères

Driving system:

T type Belt 5 mm pitch

Theoretical precision:

0.05 mm using 1/2 step mode

Spindle motor:

Proxxon IB/E milling drilling tool

Control board:

CNC 3AX

 
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