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Jan 30, 2019, 07:18 AM
A Day @ a Time - Matt. 6:25-34
ruff1's Avatar
Quote:
Originally Posted by Whiskers
A blast from the past there. Faint echoes of a bygone era.
The Bullet is a pretty little thing,
https://outerzone.co.uk/plan_details.asp?ID=4379
Good one Whiskers... I absolutely love the color scheme.
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Jan 30, 2019, 07:25 AM
A Day @ a Time - Matt. 6:25-34
ruff1's Avatar
Vtdiy, these look like flat plate flying surfaces, is that correct? How did they make them strong enough? Was it just the fact they were CL and only dealing with a certain limit of forces?

These look like they could be shipped out pretty quick.
Jan 30, 2019, 08:12 AM
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vtdiy's Avatar
Thread OP
Actually nuff1 they were very solidly built. The wing was solid balsa, 1/4" thick. And the fuselage was a solid block of balsa with a long routed slot in the bottom that stopped well before the 1/8" birch plywood firewall.

Take a 3" wide x 1/4" thick 18" long piece of medium weight balsa, and an equal size piece of paper covered DT foam. Set them on a table overhanging the edge by half, and start bending til they break. Judge for youself which has more initial stiffness, and which folds first.

A 1/2A control line plane probably has more centrifugal forces applied to its wing than any R/C plane of the same weight and dimensions. Especially with us kids trying 25 foot radius wing-overs, and the "landings" we put these poor little planes through. They were built tough! Not to mention what they had to endure from the vibration of the motor.

btw, as I remember it the wings weren't exactly flat plate. The leading edge was rounded over, and the trailing edge had about a 1" wide bevel down from the top surface to leave about a 3/32 trailing edge. About 5 minutes with a sanding block would get you there today. But maybe that machine shaping was my imagination -- I haven't seen one in 53 years!
Last edited by vtdiy; Jan 30, 2019 at 08:18 AM.
Jan 30, 2019, 08:15 AM
Build straight - Fly twisty
Whiskers's Avatar
A solid sheet balsa wing had ample strength for these small models.
Never had a problem with them, even though the models I built way back then were larger than these ones.
Jan 30, 2019, 09:46 AM
Registered User
Captain Dunsel's Avatar
Some had the machined airfoiled wing (flat bottomed, thick TE and rounded LE), whilst others had built-up wings. I remember the F6F I built had a built-up wing, covered with Silkspan and doped with good old Pactra Aerogloss.

Some of the fuselages were more than a hollowed block, too. I seem to recall the Stunt Trainer had a built-up one, for example (I did the one I built as a Junkers D1--all red, of course ).

They were rugged!

As to a flat plate airfoil, those were common in Sterling's 1/2A series (but not all -- I think the Baby RIngmaster had an airfoiled wing). I recall the F84 was flat plate, as was the Ringmaster Bipe 1/2A.

BTW, Scientific also did a large, built-up rubber job (but that would be no challenge ;-)).

CD
Jan 30, 2019, 10:05 AM
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vtdiy's Avatar
Thread OP
Yes Cap, I was just looking at some of the 18" solid wing log fuselage C/L plans in detail, and some had absolutely flat plate wings, some had shaped (foil) flat plate wings.

Some were single piece, wings, and some had an added "flap" piece of thinner balsa to give the wing more chord and shape.

I was looking on Outerzone for the Scientific 's Mr. Mulligan, but sad to report, it isn't included in the available plans. That was the first plane I ever built.
Jan 30, 2019, 10:11 AM
treefinder
springer's Avatar
I have been following this thread with minimal interest, since the plane sizes are a bit small for my flying area (get lost too soon when I am watching them fly away!). But today, while checking in again, it dawned on me that I actually have some Scientific kits that were left over from the time in the 50's when I was in Sky Pilots, back in Ft. Wayne, IN. I find I have two of the Piper Sea Scouts and half of the 2 in 1 kit. They are the block fuse and 1/4" balsa wing type. Wow, what a flash back!
Jan 30, 2019, 10:12 AM
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vtdiy's Avatar
Thread OP
P40 kit, from Outerzone:

Jan 30, 2019, 10:14 AM
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vtdiy's Avatar
Thread OP
Hey, nice Springer -- especially the view of the log fuselage and aluminum cowl! Brings back memories for sure.
Jan 30, 2019, 10:17 AM
treefinder
springer's Avatar
Ha! I'd rather have the P40! Amazing how they all survived just sitting in attics. The only thing that might not looks like the decals, all rolled up like a drinking straw!
Jan 30, 2019, 10:49 AM
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vtdiy's Avatar
Thread OP
I wonder if putting near a humidifier, or some steaming might relax them? Well, probably shouldn't unless you were building one -- it's an antique, now!
Jan 30, 2019, 11:27 AM
treefinder
springer's Avatar
yup!
Jan 30, 2019, 04:41 PM
A Day @ a Time - Matt. 6:25-34
ruff1's Avatar
Wow, that is cool... only to find a half-dozen of these in an estate sale so we could build some!
Jan 30, 2019, 06:21 PM
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vtdiy's Avatar
Thread OP
How about building one now?

I had some free time between snow plowing sessions, and decided to draw up the Thunderbird as a 22" span size (originally 15") that would probably do well with the 4 -5 oz AUW gear I mentioned earlier.

I had to reconstruct the wing and H-stab from the tiny dwg in the upper right hand corner of the original plans, but luckily, those plans are very well drafted and the proportions were right in that small illustration.

Most of these Scientific plans are not going to show the wing, so we do have to re-construct. But most are so simple that shouldn't be impossible.

I arranged the parts on legal size paper, which most small printers can handle, and I did that so there's no need to tile or tape together sheets. Just print the 3 pages straight. You can cut out the drawn parts with scissors as patterns and apply them to whatever material you'll be using as guides to initially shape them.

Block the fuselage out in side and top views, then round the corners with a sanding block and 80 grit paper. I use an old dull hacksaw blade to rough shape block foam. It cuts like butter, and the saw easily follows curves.

I suggest a 2" thick foam block for the fuselage -- hollowed out, or even better, 1-1/2" foam cut out for gear, and then laminated to two 1/4" cheek pieces -- "Monoblock" style.

The original kit had a block of balsa routed out from the bottom, and then the lower wing covered part of that, the rest of the bottom was covered by 1/8" balsa sheet.

I didn't try to draw any particular wing cross section in -- the original 15" span plane had 1/8" thick balsa wings. You can choose whatever wing material, thickness or foil type you want to experiment with (flat plate, KFM, UC) -- the patterns I show simply are the original plan scaled up. The wings are shown flat, therefore, and about 3/16" thick. You'll have to cut the fuselage wing mount locations to fit your wing type, if different, but that's not a big deal.

The wings have 160 sq in total, and the stab was plenty big for that. No need to change. The rudder is okay, too. I'd add maybe 3" total dihedral (1-1'2") per side) as a guess.

Be sure to download the original plans from Outerzone for reference when putting it together. I didn't show ply firewall or landing gear, but you can wing that from the fuselage and plans.

So have at it if you want. Maybe I'll join you, when I get a few other projects done....
Last edited by vtdiy; Jan 30, 2019 at 07:02 PM.
Jan 30, 2019, 07:04 PM
A Day @ a Time - Matt. 6:25-34
ruff1's Avatar
Very tempting. I probably should get some other things done.


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