Tandem wings (Yes, again.... Sorry!)

HomeBuiltAirplanes.com

Help Support HomeBuiltAirplanes.com:

Tiger Tim

Well-Known Member
Joined
Apr 26, 2013
Messages
3,083
Location
Thunder Bay
I still haven't figured it out.
If expressed as a fraction (which I guess it isn't in reality) you'd get L/D but expressed as a ratio the forum software sees a colon and an upper case D and turns the latter two thirds of L : D into a smiling face... I assume.

:D
 

Swampyankee

Well-Known Member
Joined
Dec 25, 2015
Messages
1,416
Location
Earth USA East Coast
If expressed as a fraction (which I guess it isn't in reality) you'd get L/D but expressed as a ratio the forum software sees a colon and an upper case D and turns the latter two thirds of L : D into a smiling face... I assume.

:D
Exactly true. Other forums using the same or similar software have the same problem. You can turn off smilies, but, as far as I know, only for the entire post.
 

Aesquire

Well-Known Member
Joined
Jul 28, 2014
Messages
2,402
Location
Rochester, NY, USA
Once upon a time there was a popular hang glider kit called the Easy Riser. A biplane, swept flying wing with "normal" stagger . A refinement of Taras Kiceniuk, Jr.'s Icarus 2.

The rear ( bottom ) wing was at a lower angle of attack than the front ( top ) wing and thus was essentially an overlapping tandem wing.

Quite stable, and one of the more successful early powered ultralights. Handy structure to mount an engine with a thrust line close to the vertical c.g.

https://en.wikipedia.org/wiki/Taras_Kiceniuk,_Jr.

http://www.pioneerflyer.com/Easyriser.html

http://www.bydanjohnson.com/?b=1&m=3&i=25

Camels didn't do too bad off a carrier.

However when the casualties in WW1 in training flying the Camel were nearly as many as were shot down by enemy action, not to bad is a bit subjective.
 

bmcj

Well-Known Member
HBA Supporter
Joined
Apr 10, 2007
Messages
13,302
Location
Fresno, California
Doesn't do well from carriers.
Then build a plane for a carrier, you can't handicap a design with carrier or VTOL capabilities and still call it an air superiority fighter. The whole one-size-fits-all approach is misguided. [/RANT] [/THREAD DRIFT]
 
  • Like
Reactions: BJC

BJC

Well-Known Member
HBA Supporter
Joined
Oct 7, 2013
Messages
10,807
Location
97FL, Florida, USA
Then build a plane for a carrier, you can't handicap a design with carrier or VTOL capabilities and still call it an air superiority fighter. The whole one-size-fits-all approach is misguided. [/RANT] [/THREAD DRIFT]
bmcj:

You are being too kind to refer to it as misguided; it is more like insane, Robert McNamara style.

wrt thred drift: https://m.youtube.com/watch?v=5_H-LY4Jb2M


BJC
 

rtfm

Well-Known Member
Joined
Jan 3, 2008
Messages
3,195
Location
Brisbane, Australia
Then build a plane for a carrier, you can't handicap a design with carrier or VTOL capabilities and still call it an air superiority fighter. The whole one-size-fits-all approach is misguided. [/RANT] [/THREAD DRIFT]
Hey bmcj - it was a joke...
 

rbrochey

Well-Known Member
Joined
Oct 17, 2010
Messages
1,503
Location
Gallup, New Mexico USA
I was around carriers a lot when in the South China Sea in the early 70's, and I know for a fact that the Flying Flea (the thread here I think) could easily take off from the Hancock (CV 12)... JMHO
 

Aesquire

Well-Known Member
Joined
Jul 28, 2014
Messages
2,402
Location
Rochester, NY, USA
Just be glad McNamara knew nothing of the Flying Flea or the entire fleet would have been tandem wing.

There's a rumor that the reason the U.S. military changed all the airplane designations was because McNamara could never grasp the U.S. Navy system of type/model/manufacturer. I believe it.

The Flying Flea variants tend to be quite good at short fields. A Q2 or Dragonfly is not, because of the reasons noted above.

I wonder if the difference is simply wing loading?
 

Norman

Well-Known Member
Joined
Nov 28, 2003
Messages
2,934
Location
Grand Junction, Colorado
I wonder if the difference is simply wing loading?
I think so. On any multiple winged airplane the farthest aft wing is the horizontal stabilizer. On a tandem AKA "equal area canard" the H-stab is simply much larger than it needs to be. Since to be stable the aft surface must operate at a lower coefficient of lift than the forward surface there's a lot of wasted area in a tandem.
 

Jay Kempf

Curmudgeon in Training (CIT)
Lifetime Supporter
Joined
Apr 13, 2009
Messages
3,866
Location
Warren, VT USA
What if you had a long fuselage with an entire airplane at each end. That means a wing and tail at equilibrium (trim). If you had that as a tandem you could basically load the fuselage anyway you wanted and you could control the lift at each end and each end could be kept trim and not stalling. So what I am talking about is basically a freewing setup at each end. That could allow a HUGE range of CG locations for the payload and it would allow flaps on each wing. It would take a computer or another trim control to manage the AOA of the fuselage I would think.
 

jedi

Well-Known Member
Joined
Aug 8, 2009
Messages
1,980
Location
Sahuarita Arizona, Renton Washington, USA
What if you had a long fuselage with an entire airplane at each end. That means a wing and tail at equilibrium (trim). If you had that as a tandem you could basically load the fuselage anyway you wanted and you could control the lift at each end and each end could be kept trim and not stalling. So what I am talking about is basically a freewing setup at each end. That could allow a HUGE range of CG locations for the payload and it would allow flaps on each wing. It would take a computer or another trim control to manage the AOA of the fuselage I would think.
OK, so load the aft aircraft heavier than the front one and then slow to minimum control speed. The aft aircraft will stall before the forward one and upset the apple cart. In physics, there is no free lunch. One technique that is typical is to make the system so complex that it is difficult to understand and figure out what is happening. Go back to the basics to determine if the proposal can work.

The joined aircraft will will always be limited to the performance of the least performing aircraft speed wise as they must fly at the same speed. Performance wise power may be transferred thru the mechanical linkage. You could put the engine in the front or rear plane or one in each. You could also transfer fuel back and forth to control the CG and then operate at the most efficient trim. You can do that in the typical aircraft also if provisions are made to shift the load (or wing) for trim.

The introduction of the free wing concept could prevent the stall but each wing must be trimmed for the existing weight distribution. The heavy wing would control the minimum speed.
 
Last edited:

Sockmonkey

Well-Known Member
Joined
Apr 24, 2014
Messages
1,752
Location
Flint, Mi, USA
If only the aft wing on a tandem was a freewing, could you get away with loading them equally so as not to waste wing area?
 

Norman

Well-Known Member
Joined
Nov 28, 2003
Messages
2,934
Location
Grand Junction, Colorado
If only the aft wing on a tandem was a freewing, could you get away with loading them equally so as not to waste wing area?
Since the aft wing is fulfilling the function of the H-stab letting it float freely would have the same effect as letting the tail of a conventional float, would it not?
 
2
Top