Hollydays arrive fast, and like every year my major problem is : to bring my plane with me or carry the scuba-diving equipment or the body-boards of my children ? ... So, hurry up, I must build a little thing , very robust, flat enougth, with good flight performances ... so was born the BOOT wing !
It' a small one meter rectangular shaped flying wing, weighting less than 500 g, made of white expanded polystyrene (the one with small balls), corrugated polypropylene and glass fibered adhesive tape. In other words, you just need 15 Euro to buid three or four of them !
The wing is hot-wire cut in a single pass. It can be done eother with the help of a CNC machine (see CNC découpe ) if you've already build one, or with more traditional technics.
The leading edge is enforced with a 4 mm barbon tube (kite shops !). To cut the shape of this tube, if you have a CNC, the shape is included in the profile, otherwise, you just need to slowly put the hot wire in contact with the leading edge of the wing to dig a circular hole. Just train on a spare piece of polystyrene !
The wing profile is a classical self stable EPPLER 186. The chord measures 25 cm, the .cut file for CNC is provided here boot.cut and boot.cnc (without leading edge)
The trailing egde is then removed with a cutter knife. Stick the trailing edge with epoxy glue, paint the wing with blow pen, then cover the wing with the glass fibered adhesive tape. Elevons are made of balsa sticks thinned, covered with plastic tape and fixed with BLENDERM adhesive tape.
trimmings are :
- depth : +15mm/-10mm wrt neutral
- direction : +15mm/-10mm wrt neutral
- a 50% depth/direction mixage is needed. can be acheived with mixer électronique aeropic ...
Now, you need a body or a nose for the animal ; it's made of 5 cm polystyrene. It's used to receive the battery and the receiver. With 4 standart 500 mA to 700mA cells the center of gravity is well located when the following gauge is used :
The center of gravity is located between 4,5 and 4,7 cm from the leading edge. If you have modified the wing dimensions, you can use the excel page to compute the CDG position : aile_boot.xls .
I've equiped this with with two Hitec micro servos, but stabdard servos may be used successfully . Holes are digged in the wing so that servos are strongly fastened .
The two servos are fixed together with a glass fibered adhesive tape strip before being inserted into the hole, then they are maintained in the right position again with glass fibered adhesive tape. A small triangular piece of polystyrne will replace the lmissing part of profile behind the servos.
The nose, cut to receive the battery, is covered with glass fibered adhesive tape, and then stuck under the wing with double sided adhesive tape.
It is then wrapped with a plastic strip (holes are perpendicular to the body) stuck with double sided tape including the servos : it's like concrete !
Then stick the two lateral body profiles, and the work is over ...
You may or may not take time to decorate the body ...
fix the piano wires controls to the servos and control horns, and go to the slope !
STOP, wait a little bit, you need two winglets made of the same polypropylene or better 6mm depron . They are stuck with double sided tape at the ends of the wing, fixation is ensured with an adhesive tape wrapping the winglet and the bootom of the wing. You will never loose you winglet even after a strong touch during a combat...
Now, go to the slope and enjoy the BOOT wing ;-)
flight :
The wing has been tested in Bretagne at Menez Hom among plenty nice planes ... The BOOT flyes like a bird from very light wind up to 50 Km/h tempest !
With small wind, don't think you can shake it and do 3D voltige ... you can just do quiet and efficient thermal flight.
Whn the wind grows, just put 50 to 80g lead mass fixed one centimeter in front of the gravity center. Trim it down and the wing is really nice. Curves can be very fast and elegant .
Barrels can be done, obviously with some height lost ... Loopings are somewhat hazardous,, in the best condition, thet finish in a nice " , ", the wing turns on itself at the top of the loop, otherwise, it refuses .... Back flight is a piece of cake, half barrel, push the depth and that is !
The wing is chock-proof and chock qualified ! After 15 days of flights, several touch and no go during combats, hard retruns to the ground ... it's still alive and even the winglets !
Have fun, bring it everywhere, it has been designed for this ;-)
Please, if you decide to build one, send me a picture !