Tempest 370 (oz5740)


Tempest 370 - plan thumbnail image

About this Plan

Tempest 270. Simple 1/2A free flight power contest model.

Quote: "Good answer for the contest-concious junior who is not certain he is ready for the high performance of free flight models. Tempest 370, by Frank Heeb.

When our author submitted his article, he accompanied it with a letter that should be read by all who are interested in the Junior situation. To us, this represents the best and simplest approach to the Junior - design for him, work with him, accept him and the problem is no longer there. We are taking the liberty of publishing it in toto.

I have built free-flight contest models since 1940 and won 2 firsts at the Nats; one, of my rubber jobs was published in MAN, 7/54. The model presented here is an enlarged and simplified version of a Hornet job built and flown in 1960-61. This design is based on:

1. Ease of construction, standard sizes of wood, can be built fast.
2. High strength, low weight. 370 sq in wing with 7.2 oz gross weight.
3. Simple design, constant chord surfaces, square fuselage, pylon.
4. Aerodynamically average, no extremes of aspect ratio, moment arm, dihedral, areas, etc.
5. Very easy to adjust and fly, large enough to handle TD power.
6. Very good performance, fast spiral climb, extremely good glide.

All these features can be seen by reviewing the plans. Although most of the parts are used in the structure, nothing is complex except gluing the parts together. Accurate ribs, made from a template require only assembly to spars and leading and trailing edges with little or no sanding.

I designed the model about a year ago, and my son, 8 years old at the time, decided to build his with mine. I made metal rib templates, told him what wood to use and 'forced' him to use sandpaper more than he wanted to! (This was the only help given to him.) It was his second paper-covered gas model and went together quite easily for him. In fact, the larger size 1/2 A makes construction easy, since the parts are large enough to be handled.

I built 2 models along with his one, and they all flew alike. Slight wash-in on the right wing and stab tilt were the only adjustments required.

This model should appeal to the youngsters starting out and is certainly recommended over the small poor flying .020 model currently designed for beginners. .049 size engines start and run so much better, and such engines in a large easy-to-fly free-flight are a more sensible approach. And if my 8-year-old can build and fly this model, with just a little encouragement and advice, any of the Juniors can.

As MAN well knows, getting the Juniors started is a problem. The juniors are not replacing the seniors and open; this was very evident at the Nats last year. An easy to build and fly contest model as this one should appeal to the youngsters and help get them started. Thus, I purposely left myself out of the photos.

Tempest 370 is not the ultimate prod-uct of a series of contest-winning de-signs developed during the last several years. Rather, it is the second model of a design that originated in 1961. After building free-flight models of all sizes and shapes with high and low aspect ratios, thrust lines, CG locations, etc., with mediocre contest success, I decided to build an average contest model. I reviewed drawings of the Ramrod (oz6344), Spacer (oz6593), Starduster (oz2098), Zeek (oz5040), and other well-known winning designs of the past ten years. The Tempest id the result, its design featurtes from the old winners are readily apparent.

Multispar wing and stab with medium aspect ratio and square tips are used for high strength and rigidity with low weight. Flat bottomed sections..."

Direct submission to Outerzone.

Update 21/10/2018: Added article, thanks to RFJ.

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