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Jan 02, 2020, 04:07 PM
Alpha Whisky
AlphaWhisky's Avatar
Hey Footrrot,

Love that Tui Glider. That was my first model too. My dad gave me one for my birthday in November 1949, and then I was most impressed that Santa was smart enough to give me another for Xmas same year....

That got me started on all this and now seventy years later I`m still going at it......

Alan W
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Jan 02, 2020, 05:38 PM
Registered User
Love the discussion on the control surfaces of the Twin Fin Pusher!

Bruce, your arguments sound very reasonable. There's just one point that steers me towards elevator on the rear wing. The CG is given at the trailing edge of the front wing, so the lever arm for pitch changes would be very short.

I guess, I better start a thread of it's own soon.
Jan 02, 2020, 09:08 PM
B for Bruce
BMatthews's Avatar
Thread OP
I'm getting the urge to build a Delanne style test model. I have to admit to my own curiosity.

Keep in mind that the control surfaces are part of the fixed portion they are attached onto. The forward wing/surface "flaps" might be right at the balance point but they overall wing surface applies the forces up through the 25% mac point of the wing. And that is well forward of the CG.

But on the other hand it is fairly short coupled... Which is why it would be fun to build a quickie Delanne or "Kwiklanne"...
Jan 03, 2020, 02:28 AM
Registered User
mhodgson's Avatar
Interestingly this design used rear ailerons only, but suggests both front and rear surfaces were used for pitch (though it doesn't say how), while the front ones could be used as flaps as well.
https://en.m.wikipedia.org/wiki/Mauboussin_Hémiptère
Jan 03, 2020, 11:50 AM
Registered User
Bruce - thanks again for starting the Double Vision 2020 build off, exactly what I needed to motivate me to build one off my list to start the new year.

Wing build method for my Little Red Twin, funny that you mentioned, questioned, suggested on build method for the wings. I enjoy and prefer the traditional built up wings (D-tube construction) but have always wanted sheet wing(s) a try. I checked out Ken Willard’s wing construction on his Good Neighbor per your suggestion. https://outerzone.co.uk/plan_details.asp?ID=7262. I trust Ken - a very prolific designer / builder.

I also know from my friend, Joe Wagner, that he used a sheet wing in many of his models such as the Dakota. I just read through his Osprey article / plans which describes his steam / mold technique: https://outerzone.co.uk/plan_details.asp?ID=7191

Joe also recommended using the Jedelsky (or KF- Line-Fogleman) airfoil on balsa sheet wings. The benefits being added strength and better stall characteristics. This is just a simple step on the leading edge that created a vortice / camber effect. Larry Kruse used a combination of Ken’s and Joe’s styles in his Old School design from his May 2018 Model Aviation article:http://www.modelaviationdigital.com/...ticleId1381975.

I am leaning towards Larry’s method of sheet wing with Jedelsky airfoil and a few ribs - should be fairly simple to achieve.

Starting build thread, my top thing “to do” for today!

Brian
Jan 03, 2020, 01:58 PM
B for Bruce
BMatthews's Avatar
Thread OP
Brian, you brought up a lot of other worthy options there. Any of them would work well.

Weight wise I think the 1/32 upper and lower sheet Willard style has the nod. But the others are going to be more durable if you stay faithful to the fairly thin airfoil. The Willard style needs a fairly good amount of thickness to get the arching of the top sheet to keep it from bowing inwards. So not so good an option for a thin airfoil... unless you opt for some spacers masking as "spars" inside to better support the upper sheeting.

All in all though I think I'd go with your idea of a Jedelsky, Wagner & Kruse inspired method.... Geez, that sort of makes them sound like a law firm, eh?
Jan 03, 2020, 10:29 PM
AndyKunz's Avatar
I was showing Matt Andren the drawings at work today, and told him about this thread and how "2" is so important.

He suggested a real challenge: https://en.wikipedia.org/wiki/Kamov_Ka-26

2 engines
2 rotors
2 front wheels
2 rear wheels
2 booms
2 fins
2 crew
2 passengers

Build it, and you'll probably get second place!

Andy
Jan 03, 2020, 11:14 PM
Registered User
Andy - Tell your friend he needs to enter the DV build!

Had me laughing trying to imagine what this flying machine looked like before hitting the link.

Now where are the plans for it pre-1970?

Brian
Jan 07, 2020, 08:55 PM
Intermediate Multi
Trisquire's Avatar
Quote:
Originally Posted by AndyKunz
I was showing Matt Andren the drawings at work today, and told him about this thread and how "2" is so important.

He suggested a real challenge: https://en.wikipedia.org/wiki/Kamov_Ka-26

2 engines
2 rotors
2 front wheels
2 rear wheels
2 booms
2 fins
2 crew
2 passengers

Build it, and you'll probably get second place!

Andy
It should be easy enough to kitbash a cheap electric coaxial. They're a dime a dozen these days.
Jan 08, 2020, 12:44 AM
B for Bruce
BMatthews's Avatar
Thread OP
BUT..... Not 50 year old plans I daresay..... This is still the "Vintage & Old-Timer Designs" forum after all.

I'm not sure but I think the first single rotor helicopters were just beginning to appear in 1970. never mind any fancy stuff.
Jan 08, 2020, 08:52 AM
AndyKunz's Avatar
Yeah, I think the only place you'd find 50 year old plans is a dusty old vault in Russia.

Andy
Jan 08, 2020, 01:33 PM
B for Bruce
BMatthews's Avatar
Thread OP
And those would be for the full size. Not a model size.
Jan 08, 2020, 02:19 PM
AndyKunz's Avatar
But if you mistake the cm for mm, you get a perfect 1:10 scale model

Andy
Jan 08, 2020, 05:55 PM
'Douglas' to his friends.
On the other hand, mistaking mm for cm ...

...

Jan 14, 2020, 06:57 AM
Alpha Whisky
AlphaWhisky's Avatar
OK Bruce,

I went on record a short time ago that I could not partake here this time round owing to other pertinent, hopefully short-term, pressures. However, I just can`t keep away from this fascinating hobby and so wandered a little and got involved in a rather simple project, partly because my modelling mates have decided to dabble with some controlline flying and partly because it is apparent that I just don`t seem to be able to keep away from carving up balsa.....

Result is I found an incredibly beat-up and almost illegible old Aeromodeller 'Peacemaker' plan. Couldn`t build direct from this mess, but have kept close to the original intent and my CL version is currently well underway. Wingspan increased a little to 40" to make best use of 36" balsa (plus 2 x 2" wing tips). Chord, fuselage length, and stab area all increased a little (disproportionally) partly because my plan is so bad and partly because I am a hopeless meddler anyway... Engine for this will be an old AM 25 diesel,

While doing all this I got to thinking about your 'Double Vision' thing ..... Next part of my project is to have 'two of something other than the usual stuff'... I`m about to start carving more balsa from the same basic plan and produce a twin to this, but this time round a (3 function?) R/C version. The original plan is dated 1957. Engine for this one either an SC 12 or a Magnum 15 glow ....

I reckon my approach here complies with all your specs listed hereunder....

Buy it and I`m in .....?

Cheers,

Alan W


[QUOTE=BMatthews;43381173]OK, it's time for the next Vintage Forum build project.

This time around the theme is "Double Vision" to go along with the palindromic quality of the year number 2020. You're looking for model designs that originated up to and including 1970 (50+ years old). Plans, kits or if you're old enough your own designs that date from that time.

Designs should have two of something other than the usual stuff. So biplanes, twin fins, twin tails, twin motors, twin fuselages or something that fits with the "Double Vision" theme that factors strongly into the structure. Along with this theme factor the following basic Vintage Forum Build selection guidelines rules apply as well;

Standard Rules for Vintage Forum Theme Builds-
  1. Models must be built from model plans that are dated no newer than the year indicated by the build coordinator in the Topic Thread.
  2. Plans can be scaled.
  3. Power sources can be modified. So rubber or glow to electric if desired. Or gliders may be converted to some manner of power source.
  4. Controls can be added or modified. So free flight designs can be converted to RC. And simple RC models can have controls added. For example a rudder only design given elevator and throttle controls.
  5. Scaled up model structure should follow the spirit of the original plan. So adding formers, uprights, ribs and such as needed to produce a durable structure is allowed. But the nature of the structure should be maintained. So no conversion of sheeted surfaces to built up surfaces. Or of open and covered structures over to all sheet.


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