Druine Turbulent (oz8223)

About this Plan

Druine Turbulent. Radio control scale model. Wingspan 60in, wing area 640 sq in, for 30 - .40 power. Fox 40 shown.

Quote: "This is one of those rare aircraft that just fly with natural grace. A joy to build, devoid of evil habits. A Stand-Off Scale R/C Druine Turbulent, by Doc Mathews.

Certain full scale aircraft possess qualities so ideal for scale models that they are developed again and again. Such classic aircraft as the Piper J-3 Cub, the Volksplane and the P-51 are selected as subjects for scale models of every size and variety ranging from Peanuts to Quarter Scale. The Dniine Turbulent is one of these repeatedly selected subjects; due in large part to it's delightful appearance and relatively simple to duplicate lines. The undeniable fact that Druines invariably result in fine flying models also contribute to this popularity.

Why then would I choose to develop a Turbulent, knowing full well that several have been published as R/C models overthe years? Simply because I like it's looks, and was challenged to design a model of it with super simple construction and near trainer-like stability. The resultant model looks surprisingly close to exact scale (though it certainly is Only Stand-Off) and flies exceptionally well.

Using several of my pet construction techniques I have built three models in this series, each incorporating needed improvements in mechanics and strength dis-covered in flying the previous model for numerous hours. The #1 prototype featured wings held on with dowels and elastics, and used scale-like ailerons. It flew well, but the wing was constantly displaced during touch and goes. The 'barn door' ailerons were felt to be an unnecessary complexity and were abandoned on subsequent models.

The second prototype used strip ailerons and nylon bolt wing hold-downs. It was a highly satisfactory model, but was destroyed in a transmitter battery failure. It flew free-flight in slowly tightening right turns for several minutes before impacting, exhibit-ing excellent inherent stability.

Number three, as presented in this article was then developed incorporating some wing saddle and tank plumbing lessons learned, plus a shortening of the tail moment for improved looping. That this final model has attractive esthetics is apparent in the photos. What is not visible is the superb flvability. I would recommend this Turbulent to any flier who can handle an H-Ray (oz658) or Kadet (oz2950) and feels ready to move on to the Sunday fun type flyer.

Anyone who has built a Kadet will quickly recognize the wing construction as coming straight out of Montezuma, Iowa. I certainly offer no apology as the Kadet wing is almost impossible to build incorrectly. It is light, but strong, and after all who am I to try to outdo the crew at SIG?

The fuselage frame is unlike prevelant contemporary technique in that it uses full length sheet siding for several reasons. Foremost is a much higher strength to weight ratio, second is cost and thirdly, alignment control. I would suggest to any-one who feels uneasy about this construction method that he take a look at the roof trusses in his home or the girders in a bridge or high-rise structure..."

Direct submission to Outerzone.

Update 5/12/2016: added article, thanks to RFJ.

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