Decalage angle

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poormansairforce

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How do you think they would look on top of a wing? Its hard to see the front tuffs but most look like they are in turbulent air. Being on the bottom I would expect them to lay down better. I had mentioned VGs earlier to check this but thats a fantastic shot. Look at some tuft videos and see if the rear ones look better or worse than yours.
The rear ones on the flat underside remind me of a wing approaching stall.
 
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poormansairforce

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https://drive.google.com/file/d/1SBT3HYy2c8acvrJgGEhIgfO0R7bWxiO6/view?usp=sharing

So, ideal aircraft should have all tufts attached to the surface? Top and bottom, sides?
Thats not good either.

If the forward fuselage is creating nose down lift, maybe that lift could be "spoiled".
If its lift then yes but then would we be creating outright drag and is that better? There is turbulence so it might already be drag.? Tough situation to deal with. I wonder if VGs would show which direction to go?
 

BBerson

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VGs improve the lift with energy input. The spoiler is opposite. About a 1" high spoiler might work without much drag (from my glider experience). But this is all WAG*. :eek:

*Wild Ass Guess (aerodynamic term)
 

poormansairforce

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I guess what I was asking is that if we spoil the lift will it make the entire curve a drag section vs getting some airflow around the curve and dealing with the lift created? It would be easy to test a spoiler as well.
 

BBerson

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I think a proper design would reset the fuselage incidence for zero fuselage lift at cruise.
That requires setting the wing incidence more negative in this case. That would bring the nose up in cruise.
The horizontal would also need to be reset more negative to follow almost the same decalage.
Another idea is reshaping the fuselage nose to provide more normal positive camber. Sort of a drooped snoot adds positive camber.
Probably should do all this with a 1/4 scale RC model.
 

AdvenJack

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May 10, 2019
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Florida - Between St. Pete & Weeki Wachee
Eugene, I truly applaud your motivation to experiment on your airplane.
We all see your determination to achieve your performance and efficiency
goals. I just wonder how much time and money you're willing to put into
your present airplane, to make what seem to be the necessary changes,
in order to hit the marks that you've decided on. I refer you to the below
attachments, that you've in essence said, you really favor. Would you see
yourself making such significant changes to your airplane, that it ends up
looking like the below? I'm just curious is all. I appreciate very much what
you've tried thus far. BELIEVE ME!!!

Sure, a guy can make enough changes to a Volkswagen Beetle made in 1965
to get it to perform like a Porsche 911. But the number of parts changed,
the time, effort and money expended, to get such performance is just not a
fair trade off. A guy might instead, just build a performance car from a raw
chassis and still be able to "experiment" along the way to great satisfaction! AirplaneDrawn Unique.png 1TwinBoom HighHorizntl.png 2TwimBoom HighHorizntl.png
 

Eugene

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May 26, 2017
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Merrill, Wisconsin, USA
As always, time and money is my limitation as well. To me Skyboy is affordable 15-25K project were I did learn so many things and tried many things relatively inexpensive. That is priceless to me. I can pretend to be one of them without spending 200K - 2Mil.

Big surprise was to find out that nobody have 100% answer for my question. I send picture of this twin boom reed airplane to Russian designer, who designed and build aircrafts below, as potential perfect pusher design. He replied to me, that he spend a lot of time trying to design similar aircraft. But decided not to do it, because at high AOA horizontal tail not getting airflow , and this is when you need it the most = at low speed. So, there is no "perfect" airplane out there.
fullsizeoutput_1470.jpeg fullsizeoutput_148e.jpeg 31288520_328347941026741_3178055063490789376_o.jpg
 

Doggzilla

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But with pusher props I wonder if that's still such an issue, as the airflow during a stall will clearly be different with propwash back there.
 
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