De Havilland Mk IV Mosquito (oz5482)

About this Plan

Mosquito. Free flight scale model twin.

Here is Richard Metlen's DeHavilland Mk IV Mosquito from RCM magazine issue 11-78. Uses foam construction.

Quote: "If you've been afraid of scale - particularly multi-engine scale designs - the deHavilland MK IV Bomber is what you've been waiting for. Combining all the assets of the full-scale aircraft in speed and maneuverability it can easily be trimmed to be as docile as a low wing trainer.

It never ceases to amaze me, how a small event will mushroom into a project that will take months to complete. On one lazy Saturday (I do most of my flying on Sunday afternoons) I was propped up in one of my favorite positions, looking between my shoes at the television set, watching an English World War II movie. The story line concerned an underground German factory that had to be destroyed, and every attempt that had been made, failed because of its access. The final solution to the problem was to fly some fast and very maneuverable bombers between the cliffs guarding the factory, and bomb the wall of the stone cliff above the factory, therby effectively burying it.

The plane they used was the DeHavilland Mosquito MK IV Bomber. I was really fascinated by the plane. It was apparently highly maneuverable (although that could have been camera technique), fast, and they kept referring to it as the 'Wooden Wonder'. After enjoying the movie, the thought of the plane wouldn't leave me, so I proceeded to get some more information on it and, besides, whoever heard of a wooden WW II aircraft?

Like the history of many of our best planes, the P-38 and the B-17 among them, the Mosquito had a tough start. The concept of a bomber that carried no defensive weapons, but relied on its speed as a defensive weapon (and made of wood in an age of aluminum) didn't sit very well with the British Air Ministry. The factors that saved the plane was the sure shortage of aluminum that would be experienced in a war, the use of existing furniture manufacturing shops where it could be built, and the success that the DeHavilland Company had experienced with wooden planes in the previous decade.

All arguments and doubts came to an end, when the Wooden Wonder showed its capabilities. With a top speed of 380 mph, a cruise speed of 265 mph, a ceiling of 34,000 feet, and a range of over 2,000 miles while carrying a bomb load of 2,000 pounds, the Mosquito became one of the outstanding aircraft of the war. This information really wetted my appetite. I had two Enya .40 engines sitting in my 'Clipped Wing P-38' (a long story all by itself), and if the wing span of the Mosquito was set at about 65 in and I could keep the wing loading at a reasonable figure, I could have a very exciting model.

The next step was to purchase a plastic model of the Mosquito and start drawing plans. Fortunately, Revell had such a model in its catalogue. Unfortunatety, Revell is no longer manufacturing the kit in the United States. Fortunately, my younger brother is the Executive Vice President of Revell, so I called him, apologized for the time when he was three years old and I told him the can of Boraxo was the can of tooth powder, and requested his help in locating a kit. He really came through, and the next day I was in possession of a very dusty, but complete Mosquito kit. The story of his foray into the kit morgue will most certainly be told at office Christmas parties for years to come.

About the same time, I became acquainted with a material called polyurethane foam, and I was using it to make and repair wing tips. I seem to be able to damage wing tips even on a high wing plane with a trike gear. Polyurethane has several real advantages over the polystyrene foam that we have become used to. Since the polyurethane foam has no texture, it is very easy to sand and cut. I have used everything from a jig saw to a bread knife on it and it doesn't rip, gouge or tear. I use coarse garnet sandpaper to get the bulk down and the results look as smooth as if I used fine sandpaper on it.

Another nice feature is that unlike polystyrene, any glue adhesive, or resin, can be used on it and the foam is not affected. As if this isn't enough to have you running out to get it, it's also fuel proof, and is about the times lighter than balsa blocks. The material I used is rated at two pounds per cubic foot. Need more? How about low cost. A 2 ft x 4 ft slab is less than $10.00 and is sufficient for the entire project If the polyurethane foam is not available in your area, you can order it C.O.D, from Hastings PlaStics, 1704 Colorado Ave, Santa MoniCa, Calif. 90404, attention Mr Tolliver.

The thought struck me that with the use of Sig Ply-lite and the polyurethane foam, the entire fuselage could be built for less than $8.00, and we are talking about a fuselage that has a length in excess of 49 in and is as much as 6 in wide in some places. The construction time would also be dramatically reduced, because of the ease of handling the foam.

Since you probably have not used polyurethane foam before, let me take a few minutes to describe how it handles, and some do's and don'ts.

The foam has no texture. This means that the finished product will be just as smooth if you use coarse garnet sandpaper or fine finishing sandpaper on it. The difference of sandpaper grit is the speed at which the material is reduced lo the desired shape. I found the best way to handle the blocks of foam is to take the majority of material off with a knife, use coarse garnet to get you almost where you want to be, and finish with 100 grit sandpaper. You have to be very careful not to over-finish the foam. The material reduces very easily and it's very easy to take off too much.

Try to approximate where the finished blocks will be (after sanding) when gluing the foam blocks together, and do not go beyond that area with the glue. If you do, you will notice that the foam will sand away leaving the glue flash behind. This glue flash cannot be sanded away without further reducing the foam (the foam being so much softer) and you will have to get rid of it with cuticle scissors, which is a time consuming job and gives disappointing results.

The foam is fairly easy to dent before the glass cloth and finishing resin are applied so be careful where you lay it and how you handle it.

Two ounce glass cloth is needed to give the foam a durable finish. The 2 ounce cloth is used throughout the model except on the cowls and tank access hatch areas where 8 ounce cloth will be used, and will be described in greater detail later..."

Direct submission to Outerzone.

Supplementary file notes

Article pages.

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