• Peter's plan and article (below) were first published in 1983 and the plan has been updated and re-published in the new August 2013 issue of RCM&E alongside Nigel Hawes' electrification project article. 

 

The Volksplane must be just about the simplest possible aircraft, especially from the scale modeller’s point of view. This model of the Evans VP-1 Volksplane was designed and built in two weeks, ‘though it must be admitted that the designer was off work at the time. The model is an ideal first scale subject and would be quite reasonable as a first low wing model. It is simple to build and is capable of most aerobatics. The all moving tail surfaces present no real problems in building or flying. My original example was powered by a G-Mark 30 twin, but any engine from 0.25cu.in to 0.30cu.in would be suitable or a four-stroke in the 0.30 to 0.35cu.in. range which would even sound like the real thing. 

The fuselage is a simple box. Cut out the sides from 3/32in. sheet, add the 0.8mm ply doublers, remembering to chamfer the ends, and then fit the 3/16in.sq longerons and up-rights. Join the sides with formers F1-2 and 4. When this assembly is dry, fit F5 making sure that the sides curve equally. This is very important. Next fit the cross braces, holding the sides in with elastic bands or clamps. Now fit the rudder bearing blocks and drill them for the brass tube bushes making sure that the drill is vertical. Epoxy the tubes into place allowing 1/16in. to stand proud above and below the fuselage. It is advisable to fit the rubber tube into the bushes whilst the glue is drying, but be careful not to get any glue on this tube, a smear of oil will help here.

The wing seat ‘treblers’ can now be fitted and the ply plate that holds the wing hold down nut, which can be slotted onto the treblers or additional supports glued in. the next stage is to fit the 1/16 in. sheeting from F2 aft and on the bottom from F4 back as far as the rudder bearing block. Fit the under-carriage mounting block and the 1.5mm ply tankbay floor. Drill F1 for a radial engine mount and bolt this into place. If using the G-Mark 30 drill the former and insert mounting bolts from inside and epoxy the heads to the former. Drill the holes for the tank plumbing and the throttle control rod and fir the tank. I stick the tank to the fuselage side with contact adhesive. The top of the tank bay can now be covered with rolled sheet. The two ¼ in.sq. supports help at this stage.

The back-rest block can be carved and hollowed now, but do not fit it at this stage if iron on film is covering is to be used.

The cowling is made up from 1/2in sheet. Cowlings vary from ‘VP’to ‘VP’ so check on the particular version that you are modelling. Mine is G-BDAH which is covered in great detail in the book, “Build and Fly Your Own Aeroplane,” by Robert Lowe, a book that is well worth reading for its amusing account of the author’s successful efforts to build his own aircraft. It also provides plenty of photos of the VP.1 and its structure and detail, also General Arrangement drawings and cutaways.

It is possible that some silencers may not fit the cowling as shown, in this case cut away F-! to clear the silencer and build a channel or duct to allow the exhaust to pass out at the bottom of the fuselage.

TAIL SURFACES
The rudder is built by slipping the ribs over the tube, gluing on the LE and TE over the plan and then firmly epoxying the tube to the ribs. Next, file a flat on the tube below the area that will be covered by the top bush. The horn is cut from a suitable steerable nose leg horn, or it can be made by soldering a strip if metal to a wheel collet. A piece of tube has a washer soldered to the end or, if a steerable tail wheel is to be fitted, a strip of metal with holes drilled in the ends can be used. When the covering is complete, the rudder tube is slipped through the top bush, the horn and bottom bush and the inner tube is epoxied into the rubber tube, the horn is located with the screw pointing to the rear so that it can be tightened through the hatch, if suitable spacers are used, it would be quite satisfactory to use the horn to retain the rudder and this set up would allow easy removal of the rudder.

The tailplane or as it is known these days, the stabiliser is perfectly straightforward in construction. The anti-balance tab is shown fully-working and while this is operational I believe that its incorporation is the reason why no trace of flutter has shown up on the tailplane. It is top hinged to the tailplane with the covering film and has a travel of about 1/8in in relation to the tailplane in the same direction.
The main hinge is a 1in brass butt hinge. Make sure that it is a good solid one as some of these are a bit on the ‘tinny’ side. The hinge is screwed in place with the wood screws after covering.

The control horn is the longest available. True, one could use an inner hole on the servo output arm, but by using a long horn and the outer hole at the servo, lost motion is reduced to a minimum. Some play will develop on the hinge, just how far this can be allowed to go is not yet certain, 1/8in fore and aft movement at the T/P tip has shown no ill effects so far and replacement is easy.

COVERING
The model can be covered in any iron-on heat-shrink film or fabric such as Solartex and film used for the trim. The back rest should be covered before gluing down. The ailerons and trim tab are hinged with film, the cockpit area is covered with matt black ‘stikartrim’ and the trim cut away to glue the pilot down, a 1/5th scale pilot is about right, though I must confess that I salvaged a 1/6th scale pilot from another model and he does not look too small. I just tell people that he is a jockey!

RADIO
I used 35MHz FM equipment and there is plenty of room for it. The battery pack will have to go as far forward as possible and the receiver can fit in the same bay if the oval slant-front Sullivan tank is used. The servos can then be placed to bring the C of G to the correct position which should be 21/8in back from the LE. With the G-Mark 30 this was no problem, the servos are well back in the servo bay. With a lighter engine, the servos will have to be further forward and care must be taken that they do not foul the aileron servo. I mounted them on their servo rails, put a bit of scrap 1/16in sheet under them and stuck the servo rails in with suitable supports and then removed the scrap sheet.

Push rods are made from ¼ in. balsa and a little fiddling may be needed to get the elevator pushrod past the rudder post without any binding. The rudder pushrod has a clevis at the horn which can take some juggling with a couple of small screwdrivers to engage. Adjustment is eased by removing the servo disc and rotating the whole rod.
The throttle run will depend on the engine used, wire snakes are probably the best system.

FLYING
Check the C of G again, check that the control movements are as specified on the plan, and particularly that the elevator movement is correct. The ailerons are effective, the rudder is not very effective but the elevator is very effective.
The model is stable, and once trimmed out, will fly hands off for some time. Once it deviates from its path, correction must be made but there is plenty of time. For this reason it is ideal as a first low wing model. Take offs are no problem, plenty of ‘up’ elevator until she is rolling, then ease off till the tail comes up. Be ready to feed in some right rudder, then a touch of ‘up’ elevator and she’s away.

Flying at all throttle settings is steady, but if the engine stops she will put her nose down in a steep fast glide. It is for this reason that I recommend that the trim lever be towards the ‘down’ end of its travel when the model is trimmed-out as it gives a steadier pull out by feeding in up trim. NOTE - this is not a problem, just a flight characteristic to be ready for.

The full size Volksplane is capable of loops, barrel rolls and stall turns, the model is far more aerobatic. Loops are easy, rolls are nice in both directions, positive and negative flick (or snap) rolls are good but need ailerons to help. Inverted flight is easy but, due to the flat bottomed wings, needs lots of ‘down’ held in. Spins are entered easily and recovery is instant. When spinning, if the rudder and elevator are reversed she will instantly go into an inverted spin but again recovery is instant on centralising the controls.
Landings are easy but good landings take practice due to the very effective elevators, one occasion when dual rates would be a great help.

To sum up, a scale model that is easier to build than the average trainer, is docile to fly for a first low winger and yet agile enough to prevent boredom from setting in and, a big point, very cheap to build. 

LINKS
Evans website (for variants, colour schemes).

Airliners.net (for more schemes and variants).