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Discussion in 'Aircraft Design / Aerodynamics / New Technology' started by FritzW, Oct 26, 2015.
Nothing I just wanted to get that Banana Nut Bread recipe.
if it's okay with speedboat I'd like to talk about the Piojo a little more...
Coming up with a mixer and a pivot is all doable. My question is, is a split wing the best choice considering the extra weight, complication and hassle?
(theoretical vs. practical) In theory a split wing would be very effective but in practice would it be more effective than simple ailerons (or elevons) on the rear wing?
Ok...could the strut have a pivoting point where it meets the wing...and inside of it a linkage to turn the wing half ?
Here is lithuanian way .
For the French bespoken.
The split wing would be less complicated that elevons on the rear wing.
I disagree with that.
This right here is the flea development community in a nutshell, at least from what I’ve seen.
(Nothing against VB, he just happens to be the one who said it)
a pure marvel..I watched this ...SOOO many years ago, on french tv. still very good!
We're looking at two configurations for a three axis Piojo (I say Piojo instead of Flea because the narrow fuselage is a real factor).
1) a regular one piece flea front wing (pitch) with a fixed rear wing with ailerons (roll) and a rudder (yaw).
2) a split front wing (roll and pitch) and a *rudder (yaw).
*I know Sockmonkey says you wouldn't need a rudder with option #2 but then it wouldn't be three axis.
#1 would just use standard controls, no mixers. A linkage for pitch and 4 pulleys for the ailerons. Pretty simple and easy to stuff into a narrow fuselage.
#2 would require a mixer that would fit in a very narrow fuselage and a wing pivot mechanism that really made sense (handled drag/anti-drag loads and had the same stick force in both directions, the one in the Spraat patent drawing wouldn't)
And I don't see how a UFO/Horton ML stick mixer would work on a Piojo.
It's easy to get seduced by the coolness of a split wing but in reality I think it would be a complex PITA to make happen.
Please stay on-topic for the thread.
IMHO, do a traditional Mignet-formula "flea" and add ailerons to the rear wing. Simple, full-three-axis, and utterly familiar to any pilot.
Don't actually call it a "flea", and the Mignet purists will be happy-ish.
If this chair wasn't stuck to my butt I'd go carve a 1/4 scale Piojo out of foam and see what happens. I'm sure I've got enough RC stuff laying around.
Lost the prank war, eh?
A traditional pitch control flea fore wing already has 90% of the bits you need to make it a split wing. Now, I wouldn't make the wing try to do yaw control as well because that would make it too complex. For full three axis I would use the standard pedals and rudder setup.
In fact, the Horten Mixer would also work in the Piojo Fuselage, the arms would only be about 3-5“ long from the Stick.
They could even be installed on top.
What's the benefit of a split wing over ailerons? I can see three significant down sides to a split wing with no real benefit.
1) the mixer would be more complicated and heavier
2) the pivot would be complicated and heavy and a real opportunity for a single point failure
3) there's a gap, right where you don't want one, with no practical way to seal it.
For the added complexity, weight, cost and build time there'd have to be a very significant benefit.
The mixer need not be any heavier than any other mixer, but if you don't need a mixer it would be heavier than discrete controls.
If you are going to use a Cosandey flap on the rear wing than traditional ailerons would be the logical choice.
The leverage and precision would have to be above average to split the wing. Just like the aoa for the front wing going negative pinning the control, you want to introduce the same action to roll? Also zero play in the action. You will have a wing fluttering with any play in the system. With that, the spar has to have bearings. They have to rotate under G load and not have play. You probably need a hydraulic system to guarantee control.
Roll for a flea, I think, would best be on the rear wing allowing only up movement. Like a flipper. No adverse yaw and with the rudder at the same spot you could not counter it much anyway. You are not going to make a fighter plane out of a flea. It’s meant to be Simple Stupid. Without that one key point, it can’t be a flea.
While we all want to eliminate adverse yaw, up-only "ailerons" on a flea would be problematic in practice. A "flea" is a subset of the larger class of tandem-wing airplanes, where the CG is somewhere between the fore- and aft-wings (but usually closer to the forward wing, for stability reasons). As such, since "up only" ailerons reduce the total lift from a wing when they are deflected, this would result in a pitch-up with every roll command: Lift from the rear wing is reduced, and lift from the forward wing is not.
Best to have conventional "up/down" ailerons, just like the Quickie, Q2, Q-200, and Dragonfly tandem-wing airplanes.
See? Not complicated.
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