Speedwagon 20 (oz16678)

About this Plan

Speedwagon 20. Control line speed model. Wingspan 12 in, for class A engines.

Quote: "INTRODUCTION: In all fairness to the model builder we believe that he should be told in advance that this is an extremely high speed model of the most advanced type. As such it is not intended for the uninitiated modeller, but rather it is intended for the builder who wishes the finest that is to be had regardless of whether it might be an 'own design' or another kit model.

DMECO has spent considerable time and effort in the development of this design until you can be assured that every flight will be at near record speeds. In order to do this we ask that you adhere to the plans closely and follow the instructions for building and flying to the best of your ability, this will not be -found hard to do as it is of the simplest possible type of construction and flies very definitely in the 'groove.'

Following is a step-by-step description of how to do it. If you will use this in conjunction with the drawings we believe that you will find the Speedwagon 20 to be a joy to build and a dream to fly!

CONSTRUCTION: ENGINE CRUTCH: The- engine mount for your Speedwagon 20 comes ready made and should require only a slight amount of fitting to your own particular engine. In fitting the mount to the engine be sure to do the same for the tank, as it will help in mounting your tank later on. After fitting the engine the holes should be drilled for the motor bolts. Make them a bit undersized and screw the bolts into them. They are kept from turning by a small piece of piano wire soldered in the slots.

MOUNTING THE CRUTCH: This is quite important as it determines the amount of offset thrust you will have, which in turn keeps your model flying around the circle. First determine the centre line of your fuselage bottom after which you can strike another line 2 degrees to the right as shown. The centre line of your crutch is lined up with this 2 degree line on the fuselage bottom which becomes the thrust line of the model. A line is drawn around the outline of your crutch so that you can set the crutch very neatly into the fuselage bottom. When this has been done you may roughly hollow the bottom out and cement the crutch in place. After this has dried mount your engine in place temporarily.

COWL CONSTRUCTION: The first step is to hollow the inside of the top fuse-lage half just enough so that it will fit tightly down and around your engine which has been mounted on the bottom half. When this has been done lightly cement the top half in place.

Now take the precut cowl sides and fit them to your own engine so that about 1/32 clearance is present between the cowl sides and the cylinder fins. The cowl sides are lined up on the thrust line so that the forward opening is 1/4 in wide and the rear opening is 3/16 wide at the cylinder fins, these measurements are quite important and should be held to a close tolerance. The top of the cowl is now fitted around the Glow Plug and cemented in place also.

When this has dried the entire fuselage is trimmed down to its final size and sanded to a smooth finish. It might be wise to say that the better the finish you have on the inside of your cowl, the more efficient this unit will work, so make an effort to build your cowl as the plans show and give it a good finish inside and outside.

When completed, split the two halves apart and finish hollowing the inside to about 1/4 in wall thickness after which the shear dowels and the hardwood tail block may be installed. The 1/4 in dowels for the tie down bolts and screws are now installed using plenty of cement.

WING: The simplest way to build this wing is in the inverted position as this gives you a straight edge to work with. To start it you may cut out the ribs to outline shape for the wing recommended for your model. The leading edge is already notched to suit your wing and the ribs can be cemented in place, aligning them with blocks of scrap balsa. When this is dry the top wing sheeting and the aluminium tubing may be installed followed by the bottom sheeting.

Now the pivot bolt is placed in position on the ply-wood control mount which is in turn cemented in position on the bottom of the leading edge. After drying, the wing is carved and sanded to shape keeping the airfoil as true to the original as possible..."

Direct submission to Outerzone.

Quote: "Hi Steve, Attached are scans of the iconic Speedwagon, this the "20" or Class A version. Some points:
- the model is intended for clockwise CL operation, since the usual ACW rotating (when viewed from the front) propeller gives some benefit to a speed model that is circling clockwise.
- the model incorporates a 'circular' flight fuselage where the centerline of the fuselage matches the flight radius.
- this is a version that was sold (and produced?) by Mercury for the UK market.
Since by the 1950's, most flyers had settled on anticlockwise rotation, I imagine quite a few of these may have been constructed for anticlockwise rotation - resulting in a model with a fuselage banana'd the wrong way.
regards, Richard"

Supplementary file notes

Instructions.

Corrections?

Did we get something wrong with these details about this plan (especially the datafile)? That happens sometimes. You can help us fix it.
Add a correction