Catapulte simple

avec pédale de déclenchement sur la rampe

PRINCIPE

Catapulte avec pédale de déclenchement sur la rampe
et
écartement non ajustable

fabrication en bois
Vue de l'arrière

Je ne l'ai pas construite, je vous donne les caractéristiques tel quelles ont été décrite
dans la revue S&E Modeler

Cette rampe est construite à l'aide de 4 planches identiques
de 16cm de large et 2,5cm d'épaisseur
de 90cm de long pour petit avion, de 120cm pour plus grand

En fait, choisissez en fonction de la taille de votre coffre voiture

Vue de face

A la construction faire un écartement entre les deux planches horizontales de 2cm

Ces deux planches sont exactement de même largeur
une rondelle fine de chaque coté du pivot suffira à l'écartement pour basculer
un simple clou comme pivot est suffisant
(c'est pas moi qui le dit, c'est l'article).
Vue de coté

A droite le boulon de 15cm est pour tenir dans le sol
personnellement je pense que cette solution donne une gêne pour le transport
je préfére avoir une planche du fond 5cm plus longue
avec deux trous
pour passer des piquets
de toute manière il faudra emporter le marteau.

A gauche, le boulon, qui retient l'anneau, sera limé, pour faciliter le décrochage de l'anneau

Notons, enfin, qu'il n'y a pas d'angle de décollage
cela n'est pas prévu dans leur plan
néanmoins
Rien ne vous empêche d'en mettre un
Article décrivant la construction
dans S&E Modeler numéro V4N5 Septembre 1999
plan #137 coût $12
coût fabrication $70
PO Box 4250 W. Richland WA 99353
(866) 627 0456
Partie du texte de l'article d'écrivant la construction.

A lire pour votre plaisir uniquement. J'ai mis toutes les informations pertinantes en Français sous les photos.

Assuming you have the four 1x 6x 36-inch boards cut to length, take two of thern and clamp them together one on top of the other. Measure 2 1/16 inches from one end and drill a 3/8-inch hole through the center of the boards. Now, take the clamps off of the boards and enlarge the 3/8-inch hole in» one of the boards to 3/4-inch and setId aside. At the opposite end of the board that has the 3/8-inch hole, center drill a 1/4-inch hole set in 1 inch. Next, using the board that has the 3/8-inch hole at one end and the 1/4-inch hole at the opposite end as the bottom of the launcher, take the two remaining boards and make a three sided box or a channel out of them. This means you will have a bottom and two sides. Make sure the bottom board has the 3/8-inch and 1/4-inch holes in it. Secure the sides to the bottom board using the finishing nails. Refer to the drawing.

Next take the 3/8- x 4-inch bolt an ut the 1 -inch of thread off using hack saw. Place one of the 3/8-inc washers over the 3/8-inch bolt an using 5 minute epoxy, glue the bolt int the 3/8-inch hole that was drilled in th bottom board. Make sure the bolt is sticking up into the box and not sticl ing out the bottom. Now locate th 1/4- x 5-1/2-inch bolt with nut an washer. Place this bolt through the 1/4 inch hole that was drilled into the bo tom board so that it sticks out the bo tom of the board. Secure the bolt i place using the washer and nut.

Next, you will need to make two shims that measure 3/4 inch in heigh Place one at each end of the bottor board. Now place the board that ha the enlarged hole to 3/4 inch on to the shims so that the 3/4 inch hol over the 3/8-inch bolt. Hold the bo in place using masking tape at the e Lay the box on it's side and meas from end to end to the center mark. Now measure from the bottqn up 1-7/8 inches and mark. Do this fo both sides.

Once marked, use a hammer an the two galvanized nails to secure th center board in place. Now you ca remove the masking tape and the tw 3/4-inch shims. If done correctly, th center board should rock from one sid to the other. If the center board is to tight, simply take a screw driver an( pry the sides slightly away from th center board. The use of a 3/8-incl washer on each side of the center board at the nail locations will also allow the center board te move more freely.

Locate the 2-5/8- x 36- or 48-inch polyethylene foam pipe insulation pieces and open up the pre-cut side and slip them over the top edges of the sides of the box. You may want to use some House Hold Goop' to secure them in place. At this point, you need to set up the hi-start tubing. At both ends of the tubing, you need to secure a metal split-ring. One split-ring is used to stake the tubing into the ground and the other is attached to the airplane's towhook. Attach each split-ring by feeding the tubing through the splitring and folding the tubing over onto itself Use a strong kite string to wrap around the tubing and then use thin Cyanocrylate glue (CA) to secure the string in place. On the end that will attach to the plane, tie an 8-inch piece of nylon string to the split-ring


UP