DeHavilland DHC-6 Twin Otter (oz14003)

About this Plan

DeHavilland DHC-6 Twin Otter. Radio control scale model twin, for 2x OS 30 engines. Wingspan 86-2/3 in. Scale is 1/9.

Note this plan is stamped: "Restored by great_plans 2007".

Quote: "DHC-6 Twin Otter. By Roy Scott and Bill Northrop. Here is twin engine sound and performance without the hazards of single engine emergencies.

This R/C construction article is quite apart from the usual, for two reasons. The first reason, to be absolutely truthful, is that the article we expected did not come through in time. It is very comforting to have articles stockpiled so that, in an emergency, you can dust one off and publish it. Several magazines do this. We, on the other hand, prefer to live dangerously, and try to survive from month-to-month with fresh material - of course, you can't win 'em all .

The second reason for this article being different is an off-shoot of the first - we had the plans, and the makings of a text, but no photos!

An acquaintance of ours, dating back to around 1967-68, with whom we have lost contact (if you're out there, Robin Lehman, please get in touch), commissioned Roy Scott, of England, to create the design. The model was built and flown with outstanding success, and was subsequently published in the great Japanese magazine 'R/C Technique'.

By now, we had lost track of Robin, but had gained a new acquaintance in Japan, Yoshiro Sato. He in turn, obtained permission from R/C Technique's Editor, Mr Tadokoro, for us to reproduce the article in Model Builder, and even provided us with a paraphrased translation of the text!

Meanwhile, Mr Tadokoro had loaned the original drawings, with English call-outs, to Larry Hoffman, who lives in Japan. Fortunately, Frank Schwartz, who was our R/C editor at the time, went to Japan on a buying trip for his women's fashion store business back in Nashville, Tennessee, and while there, picked up the plans from Larry, and delivered them to us in Santa Ana. And you think TV soap operas are complicated!

The momentum behind all this effort, we must confess, was not so much to treat our readers with an interesting R/C scale twin, as it was to satisfy our own desire to build this model. It was our idea to build one and use it for model photos with the article. Unfortunately, we have been forced to put the cart before the horse!

However, perhaps it's all for the best. Each day, as we drive to MB's office, we pass the US's busiest airport (by statistics), Orange County. And almost every day, we see an Air West Twin Otter on its way to or from Los Angeles International. A brief detour on a recent mid-morning, netted the photos on these pages. Why build from someone's scale model - here's the real thing!

Although OC officials wouldn't allow us on the ramp, the Otter parked very close to the fence, and we could shoot through the mesh at close range without blurring the image. Twin Otters are used as feeder liners in many parts of the country, but if you're building this model, need some details, and can't find an Otter, let us know what you want and we'll shoot it for you!

While giving credits, we'd also like to mention Dave Allen, of Ontario, Canada who wrote us about his Twin Otter model which was displayed at the 1974 Toledo Trade Show, and was featured in a photo published in the May 1974 issue of MB. Several of his ideas have been incorporated into the drawings we have presented.

Aconstruction project of this magnitude is not aimed at the 'but the spars are an inch too long' kit assembler. However, a genuine MB model builder will find it to be quite basic - the wood bill may be a little high.

If you've ever wanted to build, fly, and especially listen to a twin engine airplane, but were turned off by what you've seen or heard regarding the usually fatal flight characteristics of a twin that suddenly becomes a 'single', the Otter may be your answer.

We think the best way to convince you of the Otter's recommendations is to go through its flight instructions first. It should make a believer of you. Incidentally, remember that the original model was built to fly as close to scale speed as possible. It was powered by 0.5. Max 30 engines, and was not intended to be a 'bi-motor bomb.' Don't put larger than sporty-forty engines in it.

Incidentally, the following flight instructions and building suggestions are based on information from Roy Scott, who designed and built the prototype model.

1. Run in both motors before installation in the model. A sick or badly tuned engine can only lead to trouble.

2. When both engines are happy, through a full range of speed, they're ready to go!

3. Tune each motor for maximum power. If they don't synchronize at full power, do not tune down the faster revving motor, as the power loss could be critical (remember, this is in reference to .30 cu in engines). Instead, trim the rudder in the direction of the faster engine.

4. When motors are running at optimum power, hold the models nose-high for at least 20 seconds. If either engine slows down, it's too Jean. Open the needle until the engine will hold power while pointed up.

5. As two motors cause much more vibration than one, check servos for good operation with both engines going full bore. The best check is to suspend the model in the air using two helpers..."

Direct submisison to Outerzone.

Supplementary file notes

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