Double Feature (oz14030)
About this Plan
Double Feature. Free flight power model.
Quote: "Double Feature, by John Sprague. Designed especially for the Anderson .065 this fine gliding pylon doubles in Classes AA, A by interchanging with .049 Cubs, Torps, Wasps, etc.
A seldom seen two-class combination free flight is the A and AA model. The reason is that the difference in power between the smallest and the largest Class A motors is so tremendous that such a combination would seem to have small chance, at least against the 400-500 square inch jobs. Yet any combination is worth working out and the A-AA ship is not as hopeless as might be supposed.
For one thing, a good AA model can give any free flight a tussle in any but sufficiently windy conditions that would cause the smaller plane to get out of sight minutes before a maximum flight for the day might be obtained.
The Double Feature interchanges an Anderson .065 with an .049 Torp or Wasp. Its area is approximately 200 square inches. The rather thick wing, combining the Clark Y top and the RAF 32 bottom, permits control with the bigger engine and has a glide that compensates for reduction in climb ability as an AA. The glide is the secret of this airplane. It will outglide the average model and has some rare good traits in adjusting for soaring.
It has great resistance to a stall when gliding and can be slowed up far below the speed for best glide - if you want to. The glide circle is extremely tight and, in fact, the Double Feature bobs around in tight circles like many a hand-launched glider. The first test model was lost on entering a thermal 25 feet Off the runway. Once in the air, it will pick up anything and is a threat as long as 20 feet remain between it and the ground.
The fuselage is a crutch of 1/8 x 1/4 members with a diamond cross section; top and bottom corners also are 1/8 x 1/4. The laminated pylon of 3/32 sheet mounts on the crutch and is gusseted with 1/16 sheet triangles. The front of the fuselage is sheeted as shown, The bottom, forward is 1/8 sheet. Cross pieces aft are 1/8 square. All details will be found on the plan.
The stab is conventional and is 1/2 thick to compensate for the great lift of the wing. Spars are 3/32 square. The trailing edge should be hard TE stock 1/2 in wide. Tip fins are laminated from 1/32 sheet. Ribs are 1/20 sheet or 1/16 if you can't get the thinner material. Finished stab is arranged to pop up for dethermalizing. The fin is 1/16" sheet assembled as shown and is coated with well plasticized dope to prevent warps.
The wing is unusual in that spars run through the ribs in order not to disturb the surfaces and spoil the glide. Front spar is 1/8 x 1/4, the rear ones 1/16 x 1/4. Use hard wood for them and the 3/4 trailing edge triangle stock. Ribs are 1/16, leading edge 3/16 square. Assemble four panels, then incorporate dihedral, using joiners at the joints of spars..."
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(oz14030)
Double Feature
by John Sprague
from Model Airplane News
February 1952
39in span
IC F/F Pylon
clean :)
all formers complete :)
got article :) -
Submitted: 27/07/2022
Filesize: 836KB
Format: • PDFbitmap
Credit*: Pilgrim
Downloads: 194
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User comments
John Sprague was an alias for Bill Winter. He was a long time editor for Model Airplane News, maybe he didn't want to be accused of publishing his own designs. That picture doesn't look like Bill.Doug Smith - 25/08/2022
Several prolific designers used alias’s so as not to flood the magazines all the time with their name on every article. Sprague was Winter’s mother in law’s surname.
Jim Polles - 01/09/2022
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- Double Feature (oz14030)
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- Supplement Filesize: 1401KB Filename: Double_Feature_oz14030_article.pdf
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