What do you think about "e-soaring"?

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peter hudson

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I'm still thinking about one vs two motor pods. With one (my current plan), I need (analytically) over 5 degrees of elevator to trim out the forward pitching moment (plus a couple of degrees of rudder). That extra trim drag could be avoided/reduced with two motor pods, but then I get more intersections and surface area for the pods. (and twice the parts). It would allow for a half power cruise setting that still had fixed/optimized props by only running one side. I plan to spend most of the time with power off, so it may still make sense to stick with one pod for better soaring performance. I guess I'll have to do a more detailed drag build up and trade climb performance vs glide performance, but I feel like the level of detail needed to differentiate them is beyond Hoerner or panel methods.

So any other compelling arguments between them?
 

WonderousMountain

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I feel like the level of detail needed to differentiate them is beyond Hoerner or panel methods.

So any other compelling arguments between them?
Beyond that your motor nacelle drag will be ever so small.

My low weighted vote is for two motors, mounted Directly
Aft the D cell, whatever sizing it has gotten. The diagonal
plyon thing is fine for airliners; looks like weight in waiting.

Self launchers do the pop up motor, but they also stow it.
Tucking behind the spar is a better permanent placement.
 

blane.c

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I'm still thinking about one vs two motor pods. With one (my current plan), I need (analytically) over 5 degrees of elevator to trim out the forward pitching moment (plus a couple of degrees of rudder). That extra trim drag could be avoided/reduced with two motor pods, but then I get more intersections and surface area for the pods. (and twice the parts). It would allow for a half power cruise setting that still had fixed/optimized props by only running one side. I plan to spend most of the time with power off, so it may still make sense to stick with one pod for better soaring performance. I guess I'll have to do a more detailed drag build up and trade climb performance vs glide performance, but I feel like the level of detail needed to differentiate them is beyond Hoerner or panel methods.

So any other compelling arguments between them?

58 minutes into video, he talks about perfect motor placement.


Use two electric motors, rear motor has hollow shaft of sufficient diameter to allow a hollow carbon fiber rod to pass thru and support forward motor from vertical stabilizer. So both motors mounted on vertical stabilizer basically on same horizontal shaft. Tada, two motors with counter rotating propellers in perfect place.
 

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henryk

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58 minutes into video, he talks about perfect motor placement.


Use two electric motors, rear motor has hollow shaft of sufficient diameter to allow a hollow carbon fiber rod to pass thru and support forward motor from vertical stabilizer. So both motors mounted on vertical stabilizer basically on same horizontal shaft. Tada, two motors with counter rotating propellers in perfect place.

=CRFLIGHT =+50 % !
 

peter hudson

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58 minutes into video, he talks about perfect motor placement.
That was a nice video to watch...It seems he wasn't concerned about the trim drag of the high mounted prop, but just the airflow at the prop. Maybe I shouldn't care so much and press on.
 

blane.c

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That was a nice video to watch...It seems he wasn't concerned about the trim drag of the high mounted prop, but just the airflow at the prop. Maybe I shouldn't care so much and press on.

Also he cared about CG, with the motors mounted on and forward of the vertical stabilizer you can have a slightly smaller horizontal tail maybe and not have the wings forward swept while still enjoying a spectacular view.

Experimentation may prove that using an inverted Nenadovic' wing for the horizontal tail will reduce the area by another 15% and the drag reduced 25% compared to a conventional tail of equal area. Using symmetrical airfoils for both.

Of course you may want tail area to mount solar cells, but will the extra volume and drag be more or less equal to the additional amount of kw produced?
 
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blane.c

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=stator drive one propeller,supply current via sliding contacts (two or thri phases)
rotor rotate second propeller in opposite direction...


Contacts bad, very bad. Better two motors.

Use two electric motors, rear motor has hollow shaft of sufficient diameter to allow a hollow carbon fiber rod to pass thru and support forward motor from vertical stabilizer. So both motors mounted on vertical stabilizer basically on same horizontal shaft. Tada, two motors with counter rotating propellers in perfect place.
 

henryk

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Contacts bad, very bad.

+ DC LEMKO LEM 200 motor...(NO controller loses !)

or double BLDC +controllers...(for GYRODYNE).

PS= CRFLIGHT= better stator cooling, motor RPM circa twice propellers RPMs !

+artifical TORNADO !!!
 

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Exian

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I am still moving and do not have much time for clarity but this may be better than what you are presently thinking ... which is rather ugly, ... shame on you.

A quick and dirty sketch of the wings, try to imagine they are on a glider fuselage with an extra section of length to support the second wing.


TOP VIEW

View attachment 126877
END VIEWView attachment 126878

REAR VIEW
View attachment 126879

FRONT VIEWView attachment 126882

FRONT VIEW ISOView attachment 126884


So again quick and dirty but I think even this crude much more elegant than whatever was going on in your head.

So about 13.5m span each wing (less on bottom more on top) 2.9m chord each wing. EDIT; 0.884 m (2.9 feet) chord.


I have been toying around with idea of symmetrical airfoil in lower/aft wing and it is exaggerated.

Obviously wing tips need cleaned up but should get the general idea across.

I will have more time soon relatively speaking, a couple of months more.
There is a variation of the nenadovich biplane called the "COLAB".

This configuration was tested on a 1/2 scale Edelweiss glider. The guy also has the same Edelweiss in standard configuration (7,5 meters span).
The closed wing and V tail make it quite unusual, but it seemed to fly well (I have seen both flying).
Not sure it was better than the original, but it didn't appear to perform less. Manoeuvrability was very good.
 

blane.c

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There is a variation of the nenadovich biplane called the "COLAB".

This configuration was tested on a 1/2 scale Edelweiss glider. The guy also has the same Edelweiss in standard configuration (7,5 meters span).
The closed wing and V tail make it quite unusual, but it seemed to fly well (I have seen both flying).
Not sure it was better than the original, but it didn't appear to perform less. Manoeuvrability was very good.
It is interesting, and like you said it is a variation.

Nenadovic' wings are spaced vertically 1/3 chord apart. The spacing of those COLAB wings is much greater at the fuselage and joined at the tips. With hershey bar shaped wings the 1/3 chord vertical separation would be the same for the entire span on a Nenadovic'. Also the upper wing trailing edge and lower wing leading edge would be in plane vertically also the entire span and the lower wing 6 degrees more incidence than the forward wing on the Nenadovic'.

That is the most obvious variation.
 

EzyBuildWing

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eTractor....and it is intelligent! Coming soon to a farm near you?..............40HP..........8 hours range,..........drives itself, and can be set to follow you around the farm.
More awesome eTechnology....
 

blane.c

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There is a variation of the nenadovich biplane called the "COLAB".

This configuration was tested on a 1/2 scale Edelweiss glider. The guy also has the same Edelweiss in standard configuration (7,5 meters span).
The closed wing and V tail make it quite unusual, but it seemed to fly well (I have seen both flying).
Not sure it was better than the original, but it didn't appear to perform less. Manoeuvrability was very good.

Also a brief discussion on "V" tails beginning 1:00:45 into video.

eric raymond glider - Bing video
 

blane.c

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John.Roo

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There is a variation of the nenadovich biplane called the "COLAB".

This configuration was tested on a 1/2 scale Edelweiss glider. The guy also has the same Edelweiss in standard configuration (7,5 meters span).
The closed wing and V tail make it quite unusual, but it seemed to fly well (I have seen both flying).
Not sure it was better than the original, but it didn't appear to perform less. Manoeuvrability was very good.
Very interesting - thanks ;)
 
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