Help identifying a book on CL models
04-17-2016, 07:24 PM
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Help identifying a book on CL models
As I was digging through my plans collection I found this photocopy I made from a book years ago of the generically named "Control Line Stunter". I also photocopied the pages that had the plans on them. That's all I have, and I was wondering if anyone knew which book this came from? I can't remember, and there isn't much identifying information on the couple pages that I did scan. Anyone know which book it came from? I might build it someday, and it would be great to remember which book this came out of. Thanks!
Last edited by Heartland; 04-17-2016 at 07:28 PM.
05-20-2016, 12:47 AM
#2
Heartland,
I almost recognize the model - but not quite... I might have that book in my "archives" but no guarantee.
There've been several digest size books on CL and other forms of model flying. The phrasing suggests it was a US book - from spelling and usage. The clean, pleasant side view and color lines suggest something within the past 10 to 20 years. The straight leading edge wing may indicate somewhere toward the older end of that range. Tapered planforms are little harder to build and have definite advantages.
NOTE: Simplest way to convert to a tapered planform? Keep the quarter-chord line straight from tip to tip... that is, one quarter of the chord back from the leading edge at all points across the span.)
Since it is the quarter-chord line, move the root leading edge forward some, and the tip leading edge back the same distance. Not much...:
Then increase the root chord by moving the root trailing edge back three times as much as the root LE was moved forward. Then move the tip trailing edge forward that same distance
EXAMPLE: 10" chord rectangular wing...
Quarter-chord line is 2.5" aft of leading edge from tip to tip.
Move the root LE 0.5" forward and the tip TE 0.5" back. (area forward of the quarter chord line remains the same)(One quarter the taper.)
Move the root TE back 1.5" and the tip TE forward 1.5" (area aft of the quarter chord line remains the same)(Three quarters of the taper.)
your wing now has a root chord of 12" and a tip chord of 8". (Taper ratio - tip chord / root chord - is 0.666... slightly greater than 0.7.)
The quarter chord line is at 3" aft of the root LE (AND at 2" aft of tip LE.)
There's NO sweep, back or forward, because sweep is defined as AT the quarter chord line. These tapers are similar to those used on the F-51 Mustang, which does NOT have a swept wing!
The model in the your book's sketch HAS quarter-chord sweep: - slight FORWARD sweep as only the TE is tapered, and that forward!
For simplicity, keep a flap hinge line straight across, perpendicular to the fuselage axis. easy enough to do once you decide what % of wing area you'll use as flaps. Flaps need not be full span, and it is usually easier to get substantial flap surface chord if their outer ends are NOT full panel span. (It's hard to get solid hinge mountings into the tip end unless the flap chord is wide enough to secure the hinge.)
Tuning and trimming:- Remember, the wing is now - in effect - still that same rectangular shape, just prettier. Figure CG in terms of the average chord - that same 10" in this example! If you want the CG at "18%," and want to check it at the wing root, remember the root LE is 0.5" forward of the mean (average) chord. 18% of 10" is 1.8", a bit over 1 3/4"; add that 1/2" that the root LE is forward, and check CG at 2 1/4". aft.
It IS worth playing with these thoughts! YOU know what's involved and correctly applied. Others see a prettier, out of the ordinary model, and it will fly just as well as a plank planform, even better in sharp wind!
I almost recognize the model - but not quite... I might have that book in my "archives" but no guarantee.
There've been several digest size books on CL and other forms of model flying. The phrasing suggests it was a US book - from spelling and usage. The clean, pleasant side view and color lines suggest something within the past 10 to 20 years. The straight leading edge wing may indicate somewhere toward the older end of that range. Tapered planforms are little harder to build and have definite advantages.
NOTE: Simplest way to convert to a tapered planform? Keep the quarter-chord line straight from tip to tip... that is, one quarter of the chord back from the leading edge at all points across the span.)
Since it is the quarter-chord line, move the root leading edge forward some, and the tip leading edge back the same distance. Not much...:
Then increase the root chord by moving the root trailing edge back three times as much as the root LE was moved forward. Then move the tip trailing edge forward that same distance
EXAMPLE: 10" chord rectangular wing...
Quarter-chord line is 2.5" aft of leading edge from tip to tip.
Move the root LE 0.5" forward and the tip TE 0.5" back. (area forward of the quarter chord line remains the same)(One quarter the taper.)
Move the root TE back 1.5" and the tip TE forward 1.5" (area aft of the quarter chord line remains the same)(Three quarters of the taper.)
your wing now has a root chord of 12" and a tip chord of 8". (Taper ratio - tip chord / root chord - is 0.666... slightly greater than 0.7.)
The quarter chord line is at 3" aft of the root LE (AND at 2" aft of tip LE.)
There's NO sweep, back or forward, because sweep is defined as AT the quarter chord line. These tapers are similar to those used on the F-51 Mustang, which does NOT have a swept wing!
The model in the your book's sketch HAS quarter-chord sweep: - slight FORWARD sweep as only the TE is tapered, and that forward!
For simplicity, keep a flap hinge line straight across, perpendicular to the fuselage axis. easy enough to do once you decide what % of wing area you'll use as flaps. Flaps need not be full span, and it is usually easier to get substantial flap surface chord if their outer ends are NOT full panel span. (It's hard to get solid hinge mountings into the tip end unless the flap chord is wide enough to secure the hinge.)
Tuning and trimming:- Remember, the wing is now - in effect - still that same rectangular shape, just prettier. Figure CG in terms of the average chord - that same 10" in this example! If you want the CG at "18%," and want to check it at the wing root, remember the root LE is 0.5" forward of the mean (average) chord. 18% of 10" is 1.8", a bit over 1 3/4"; add that 1/2" that the root LE is forward, and check CG at 2 1/4". aft.
It IS worth playing with these thoughts! YOU know what's involved and correctly applied. Others see a prettier, out of the ordinary model, and it will fly just as well as a plank planform, even better in sharp wind!
05-21-2016, 07:20 PM
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Hi Lou, and thanks for all the insight! Before I get to this model, I have a 50% scaled-up Flea Whiz from Keith Laumer's book on model airplanes which I built long ago, and it needs to get finished up first. I had photocopied those plans from a book at my grade school library, but I still can't recall where these plans came from. I have carried these photocopies around in my stack of plans for years now.
I was able to find the plans page that I scanned for this model.
[ATTACH]2163559[/IMG]
I was able to find the plans page that I scanned for this model.
[ATTACH]2163559[/IMG]
10-07-2016, 06:16 PM
#4
When I look at that first attachment, it looks so familiar of a book that I used to study in the library when I was in grade school, about 1967. 629.13 was the Dewey Decimal number for the books I liked. I'm pretty sure that book illustrated how to build and fly different model airplanes. Included I think were building techniques. I was just fascinated by that book with it's technical information that was included.
