Modern day "motorcycle of the air" aircraft class?

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nestofdragons

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Did the designer crash?

I’ve heard of one gentleman crashing it, but according the designer , the builder and pilot integrated non approved modifications to his build , which led to the crash.

The later, I’ve only the designers point of view.

But the overall concept remains intriguing, but I’d add a ruder to it like the ULX from Argentina.
If my memory serves well, it was the designer/builder who crashed it and had a very long recovery in hospital.
 
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but the design, what is wrong with that or not?!
To start with it doesn't follow the Sprat formula. Take a look at the 1968 Spratt Patent and compare that with the control of the Sprat103.
From there there are structural features that only a 'designer' rather than a qualified engineer would use.
The designer was described as having a rather big ego.
That is being very kind. ;)
at least momentarily, when the front wing stalls.
That is the whole point of the Spratt - the wings should never stall - either one. Unlike the Flea formula the pilot has no direct control of the AOA on a true Spratt. If the forces are handled properly then for other than inverted flight :eek: a Spratt should be self-correcting

Decade old Sprat103 thread here on HBA:
 

Sockmonkey

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There is a lot of myth and hyperbole surrounding freewing designs and a lot of people who see one or another approach as the magic bullet. There is no reason that the Spratt controlwing couldn't work as a simple two-axis aircraft as long as the CG was placed such that the tail was lifting and the wing loading substantially higher on the front wing than on the back wing. The problem I see with the Spratt design is that you lose control in both axes, at least momentarily, when the front wing stalls.

For that reason I prefer the Mignet approach, which is not a true freewing because the incidence of the front wing is set by the position of the stick or yoke, though it approaches it (and Mignet claimed some alleviation of the rough ride in turbulence) if the pilot keeps a light hand and allows the wing to absorb the buffeting. The advantage of the Mignet approach is that the separate rudder (whether actuated by stick or yoke or pedals) provides directional/lateral control regardless of the front wing's state and you are unlikely to get a wildly asymmetric stall of the front wing since it's all one piece with no control surfaces.
That's something I hadn't thought of when messing with my 2-axis Spratt/Flea hybrid.
A fully controlled split wing means pilot error could cause asymmetric stall on the front wing which would be very bad.
The fore wing would have to be fixed and use elevons on either the fore or aft wing for pitch and roll control.
The upside is that sticking them on the aft wing would make the fixed one-piece fore wing easy to rotate or remove for trailering.
Having the elevons on the fixed fore wing would let you unplug the whole back half of the fuselage.
 

cluttonfred

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There are examples of conventional aircraft with spilt, variable incidence wings for roll control such as Daniel Darby’s non-Mignet “-chel/-chelle” designs: Cubchel, Scoutchel, Demoichelle, etc. They all have pivoting wings for roll control and I have never heard of any strange or dangerous behavior, but the approach hasn’t really caught on either.

 
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Could always use forearm rests and the wrist controller NASA used for the Mercury capsules...

View attachment 127173
Much more realistic Motorcycle of the air concept (mine, TYVM)...

View attachment 127170
I really like what Frusha's got going here. Had been considering that for my amphib but wasn't sure if I'd like being committed to the cafe racer position for the duration of a flight.
 

nestofdragons

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There are examples of conventional aircraft with spilt, variable incidence wings for roll control such as Daniel Darby’s non-Mignet “-chel/-chelle” designs: Cubchel, Scoutchel, Demoichelle, etc. They all have pivoting wings for roll control and au have never heard of any strange or dangerous behavior, but the approach hasn’t really caught on either.


Fred, to my knowledge the designs of Daniel Dalby have not independant rotating front wings. The Flying Fleas by his hand have a normal totally front wing rotating. This Cubchel has a fixed front wing.

But there was indeed a flying flea which had independant front wings. GB-10 "Pou-Push" by Briffaud. I once had this designer at the phone. He mentioned it is a very easy to steer airplane. He was not happy with the mixer he designed. Too complex. I made him a draft of a easier system and he was pleased to see it could be done more easy.
a04_05.jpg a04_3-vues.png
You can read more about it at Suggestion 4: Briffaud GB-10 "Pou-Push"

Other builders made a variant on the HM380 by adding spoilers on the front wing to create some roll control in the front wing.

All sad to see because ... the flying flea does not need any roll devise like this. All the control you need for crosswind landings are the easy to install Cousandy flaps. I explain here about them.
 

nestofdragons

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Fred, to my knowledge the designs of Daniel Dalby have not independant rotating front wings. The Flying Fleas by his hand have a normal totally front wing rotating. This Cubchel has a fixed front wing.
I need to correct myself. ****, yes, it has independant rotating front wing halves. +2 to -4 degree rotation possible. Sooooorry Cluttonfred. 🙈
 

cluttonfred

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I need to correct myself. ****, yes, it has independant rotating front wing halves. +2 to -4 degree rotation possible. Sooooorry Cluttonfred. 🙈

Not at all, nothing to apologize for, it was not obvious from the video clip. When you think about it, all ailerons are effectively changing the wing incidence by changing the airfoil. If the degree of motion is limited (and it doesn't have to be much when the whole wing is changing incidence) it shouldn't impact stall behavior any more than ailerons do. It's just seems odd compared to more conventional designs.
 
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nestofdragons

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The video Flying Flea lesson 8 mentioned :
"... flew a figure 8 above an American football
field without crossing the lines .
Try that in another airplane !... "


I can do that , with my Paraglider ; does it count ? :)

Bille
Hihi. I didn't expect that answer. 😆 Ok, i need to adjust my telling. Can any other rigid wing airplane do this? Euh ... i guess now a helicopter pilot will reply with "did you know that helicopters have rigid wings too." 🙈 ;) 🤣🤣🤣
 
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