Tandem Wing Pusher

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Starman

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May 16, 2009
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High in the Andes Mountains


Really cool graphic Starman. You've got a good eye no doubt.
Yes, a good eye, for health and nice curves. I camped in the spot in this picture, it's in Volcanoland (Washington) which has the steepest mountains in the world. That spot is quite high altitude for around here, it took two days of walking ten miles a day with a lot of altitude gain each day. All the most beautiful places are at least two days walk away, so day hikers never get there so there is a lot of solitude.

I camped at the edge you see there, where there is a huge droppoff of a mile or so with one of the biggest lakes in the Alpine Lake region of the Cascades between the edge and the mountains in the distance. Off to the leftt there is a shallow high altitude lake. While I was setting up camp a hawk kept swooping down low right around me.

There's an invitational backpacking trip early next fall, when the Larches turn golden, with my group. If you want to take a long walk in the woods with some ninjas then come along. Ninja uniforms are not allowed.
 

Mac790

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Starman

Well-Known Member
Joined
May 16, 2009
Messages
2,011
Location
High in the Andes Mountains
One MUST have a young leggy girl to pose for the press at the unveiling of a prototype, mustn't one?:ponder:.
Good idea, that's why I decided to make the cockpit side by side seating, so we can hold hands on the way over there.

Evidently the previous fuselage wasn't so locked after all :gig:

This is what I came up with so far, with some minor changes and still being a sailplane type front, but copying the S-10 drive system, I come up with something like this.

It's for potentially heavy engines and it (the fuselage) is to be able to take more than 1000hp, and 10 Gs. Like the one shown with a cast iron Hemi with a supercharger and a PSRU, I have a PSRU design already picked out that can handle the power reliably and it's a secret :) If it's cruised a lot at over 500hp it would need to have the gears changed a bit more often is all.

... that's just a maxed out scenario, for someone who wants to spend $ and go fast. It can carry a truck diesel V8, or an aluminum V8 mounted a little further back, which is what I'll use for starters.

I want it to stall at 55 knots or less so it needs slotted leading edge flaps in addition to the regular slotted flaps, with wing loading at around 30psf. Showing that wing, but first i might make a bigger rectangular or lightly tapered wing to use while I work on the high speed wing and engine.
 

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Starman

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May 16, 2009
Messages
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Location
High in the Andes Mountains
Mechanically challenging maybe but I do actually like what you're sketching. Although more conservative than the tandem wing with you started with, this has an interesting appeal.
Thanks, it still is a tandem wing in a way, but with 80 - 90% on the front depending on loading and Cl. With a mid engine you can have it look 'standard' yet still be tandem, I guess. If you have so much % weight on the front wing would you call it a tandem wing or a standard with a lifting tail?
If you have a lifting tail then most likely you have an unstable airplane. Yes, there is a very narrow margin where conventional configurations can have a small amount of positive lift on the horizontal tail but this is an extreme exception that is stable only over a narrow range of attitudes (and is usually a function of the tail's incidence). For all practical purposes, the configuration you define is most probably unstable. But a simple stability solution will tell you that fairly quickly.
I know lifting tails on conventional planes are to be avoided, although I wonder if the pitch control was on the front if it would help the stability.

In any case I was only wondering earlier if you have an 80/20 plane if you still call it a tandem or could call it conventional - I think tandem.

I think of it as a tandem wing plane with a heavier loaded front end than a Dragonfly or Q-200. Think of a Dragonfly with a couple of lead bricks in the footwells, it would probably still fly well enough and the Dragonfly is a 60/40 F/R loaded tandem.

I was hoping to have the front wing carry more than the Dragonfly, Nominally an 80/20 weight distribution. It seems to me it would still be stable if you allowed for the differences.

For example, lightly loaded, if there was no passenger and the pilot was a naked Japanese midget flying at sea level on almost empty tanks but at high speed (Low Cl) then the rear wing might be lifting as much as 25%; but if you had to fly Aunt Bertha across the country, so full tanks, and she brought her big bags with everything including her cast iron chastity belt and two .45 cal six shooters in addition to her ten ton camping boots then during takeoff with a large flap (elevator) deflection the rear wing might only be lifting 10% of the weight and the front wing 90.

If for some reason this forward loading isn't stable then it is possible to juggle the engine and wing locations enough to get it to 60/40.

The reason this design looks like a conventional plane while still being a tandem is because of the rear engine and front cockpit I think.

Thanks for your input.
 

aboazeaz

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Apr 15, 2014
Messages
94
Location
Sana'a
Hi guysI like the tandem design for short wingspan, i need both wings to make same lift .and here is my diagram handmade and I need to ask if it is OK.Where would be CG, and where the controling ailerons and flaps, do I need rudder and stabilizer for such design.Your help is of great appreciation.
 

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