Dornier Do 28 Skyservant (oz6575)

About this Plan

Dornier Do 28 Skyservant. Radio control scale twin, for 2x .15-.21 glow engines.

Quote: "Twin engined sport scale model of the German Dornier Do28 D-1 STOL aircraft curently in use by the Luftwaffe, by Colonel John H Wormley, USA.

When one's reflexes slow to the point where Quarter Midgets seem to be getting too fast and you have a pair of good .15's, what choices are left? Not being ready to become an editor or helicopter pilot ('copters fly slow, don't they?) I decided to build that multi-engine plane I have always dreamed about.

Fortunately, when I left for a tour of duty in Germany three years ago, I took with me a large supply of balsa, anticipating some long winters for building. So when the idea for the twin struck, I was ready. The STOL type of aircraft seemed a good choice for a beginner's project. The Islander and Twin Otter were being considered when I saw the Matchbox 1/72 scale Dornier Skyservant kit. Not only was this a different plane, but one that I felt I could design, build and fly - two QM's attached to a box with wings!

Every aviation enthusiast knows that Dornier has, over the years, designed many strange and wonderful multi's with from two to twelve engines in all imaginable positions. The Do 28 is no exception. It is in current use by the Luftwaffe and in 26 other nations throughout the world.

It is a simple, sturdy aircraft, these being good basic concepts for both full scale and model planes. The Skyservant has been in service since 1968 and in 1972, it set six FAI world records for it's class.

It is powered by two 380 by Lycoming engines, has a span of 51 ft and a length of 37.4 ft. Maximum weight is 8516 pounds. Take-off run is 920 ft. Maximum speed is 199 mph. There are transport, survey, ambulance and passenger versions. Dropping parachutists or cargo along with STOL operation are model possibilities as are numerous military and civilian finishes.

Although I have been building model airplanes for over 35 years, I have never built one I designed. Therefore, as an Army dentist, my qualifications are like those of the aviation pioneers, ie if it looks right, it should fly right. Well, it looked okay to me.

The wing, uncluttered by engine nacelles, has more usable surface. allowing a shorter span. The engines mounted farther forward and close in should lessen the 'P' factor effect should one engine quit. I chose to enlarge the Matchbox model eight times, making mine 1/9 scale. (I found the plastic model parts are easier to measure unassembled if you ever go this route.)

The main deviations from scale on this model are:

(1) a shorter, wider flying stab is used to minimize flexing,
(2) the engines are closer together for less vib-ration,
(3) the wing slot design is for building ease and
(4) in place of ailerons are full span flaps.

The results are simplicity, but with the intended scale-like appearance. The RCM Britten-Norman Islander 2 influenced me to go without ailerons as the Do has a very large rudder. This allows realistic STOL operation with only four channels. A fifth channel could give flaperon operation. Scale area ailerons and flaps would complicate wing construction.

Before starting construction, the serious builder should have the Matchbox kit and obtain Skyservant literature from Dornier. As you will be cutting your own parts, the scale details can be done to your desires.

I dislike building wings because most of them are supposed to look straight. Therefore, I started with the expensive part, the fuselage, where all the balsa went. I knew then I would have to finish the project. Having built numerous planes from kits and plans, I found sometimes parts do not fit, so please measure and fit carefully before applying the glue.

Cut the fuselage sides from 3/32 balsa. To obtain appropriate width sheets, butt glue several lengths of stock material with Titebond. (Titebond is used throughout except where noted.) Be sure both sides are identical and use a straight-edge to assist with the long cuts. Do not cut openings until the ply doublers are fitted. Cut the doublers with all openings from 1/8 aircraft plywood. The critical part is locating and cutting to the same size, both openings for the motor nacelle strut..."

Submitted by Scott Hinckley, Utah, USA.

Direct submmission to Outerzone.

Supplementary file notes

Article pages, text and pics, thanks to jmorin12.

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