Flattop (oz13210)

 

Flattop (oz13210) by Dave Hewitt from Model Builder 1992 - plan thumbnail

About this Plan

Flattop. Free flight power model. For 1/2A engines.

Quote: "Dave Hewitt was a successful free flight competitor from the Portland area in the 1950s. This model, the Flattop, at one time held the National 1/2A AMA Gas Record. What is especially unusual for this design is that its center of gravity is located 2-1/2 to 3 inches behind thetrailing edge of the wing. The model is built to be very light, so that the climb is improved even with the rather tepid engines used during the early 1950s.

A couple of tips about the model - just in case you decide to build one. Choose the very lightest wood you can for construction. The original designs weighed in at 4 oz. Second, trim the model so that it has a tight right turn in the power phase - it should spiral in the climb. Finally, the glideturn also should be very tight. Circles of 50 to 100 feet are the goal. The object of a tight circle in the glide is to eliminate any tendency to stall, which could be disastrous in a free flight with such an aft CG.

So, if you are looking for an unusual 1/2A design, check out this three-view, look over the 1953 Zaic Yearbook (if you can locate one) and consider building the Flattop. I am."

Direct submission to Outerzone.

Update 12/08/2021: Added pdf with original 1953 drawing from Zaic Yearbook, thanks to RFJ.

Supplementary file notes

Article.
Zaic drawing.

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Flattop (oz13210) by Dave Hewitt from Model Builder 1992 - model pic

Datafile:
  • (oz13210)
    Flattop
    by Dave Hewitt
    from Model Builder
    April 1992 
    38in span
    IC F/F Pylon
    all formers complete :)
    got article :)
  • Submitted: 12/07/2021
    Filesize: 1380KB
    Format: • PDFbitmap
    Credit*: MB2020

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Flattop (oz13210) by Dave Hewitt from Model Builder 1992 - pic 004.jpg
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Flattop (oz13210) by Dave Hewitt from Model Builder 1992 - pic 005.jpg
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Flattop (oz13210) by Dave Hewitt from Model Builder 1992 - pic 006.jpg
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Flattop (oz13210) by Dave Hewitt from Model Builder 1992 - pic 007.jpg
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Flattop (oz13210) by Dave Hewitt from Model Builder 1992 - pic 008.jpg
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Flattop (oz13210) by Dave Hewitt from Model Builder 1992 - pic 009.jpg
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User comments

Hi, I am sending photos [main pic, 003-008] of the Flattop models that we operate successfully in the Czech Republic in Pilsen. Motor MP JET 040 PB
Martin Kresadlo - 11/08/2021
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Notes

* Credit field

The Credit field in the Outerzone database is designed to recognise and credit the hard work done in scanning and digitally cleaning these vintage and old timer model aircraft plans to get them into a usable format. Currently, it is also used to credit people simply for uploading the plan to a forum on the internet. Which is not quite the same thing. This will change soon. Probably.

Scaling

This model plan (like all plans on Outerzone) is supposedly scaled correctly and supposedly will print out nicely at the right size. But that doesn't always happen. If you are about to start building a model plane using this free plan, you are strongly advised to check the scaling very, very carefully before cutting any balsa wood.

 

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