What do you think about "e-soaring"?

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John.Roo

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One of reasons why makes sense to work on "e-sponzored L/D" concept is simplicity.
Look to this video where are pilots testing ETA glider. Amazing wing deflections (imagine how looks control lines system in wings) 👍
ETA is a unique glider project - shows how can look result of "never ending fight" for super high L/D performance. Nothing against - this is one of ways...
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Just....
"We anticipate that the ETA will be for sale at a price range between €550.000 and €580.000."

What to say?
To approach to "normal glider pilots world" we need to think about:
- reasonable price
- easy manipulation / hangaring possibility (dismantling should be easily done by one man with jigs)
- simple propulsion system
- simple and "forgiving" handling characteristics etc.

Performance is important, but not the most important requirement ;)
 
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John.Roo

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John.Roo

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If you follow this thread you know that I am not real fan of flying wings.
However SB-13 Arcus has been really amazing project....
You can see also not really succesfull test of winch start...
...or very interesting spin test.

Performance has been interesting, but not outstanding so it is no surprise that we don´t see more "tail less" gliders in the air.

"Despite the modifications made to remove the handling problems predicted by the model, the full scale SB-13 still "pecked" and spun readily; when the standard spin correction procedure was applied, a new spin started in the opposite direction. Over the next few years several aerodynamic devices were tried, some of which at least improved the behaviour of the Arcus; one longer-lasting outcome from the project was the start of an investigation into whole aircraft rescue parachutes. The competition performance of the Arcus was on a par with that of other 15 m gliders of the time but it did not offer the great improvement over them which might have justified even more effort to improve the handling."
 

henryk

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Performance has been interesting, but not outstanding so it is no surprise that we don´t see more "tail less" gliders in the air.
-everything can be dan good or bad...

f.e.=BEKAS-N (AR=15, L/D=44...)

=BKB1-A (AR=10 , L/D=29.... "A"=Aerobatic !


=STATIC stability !!!

or SWIFT LIGHT (AERIANE)...
 
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John.Roo

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You are right - BEKAS-N....
... and BKB1-A...
... are also intereasting projects 👍

Seems that most succesfull is Swift.
And I agree that Switf 3 looks impressive ;)

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1635740229015.png
"Swift 3 has 1 meter more span, less wing area, and all new airfoils with increased laminar flow and more lift capability. There are also other changes to the sweep, taper, twist and control surface geometry. That is how we were able to increase the L/D from 27:1 to 35:1.
The new airfoil was developed using Xfoil inverse design methods and an iteration on prescribed pressure distributions. It has higher thickness percentage than the original Swift airfoil but with the smaller chord the absolute thickness is lower in some regions. The pressure recovery is not as steep as the original and the laminar run has been increased. The lift capability is insensitive to rain and bugs (already flight tested in rain) and the pitch moment is low and slightly negative (nose down). Sweep and twist provide the trim moment just like all Swift style designs.
The Swift 3 has been flight tested to 100 mph without any flutter or other issues. The Vne speed is around 93 mph.
"
 

John.Roo

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-why the fuselage nase part is "swift" like,not a "sb-13" like ?

or BKB1-"A" ... (arobatic)
I don´t know exactly...
I would also prefer to have better "upwards" vissibility.
However main reason are probably certification requests.
Swift is certified as "foot launch" glider and "foot launch" category has lower certification requirements than "gliders" = cheaper development / certification costs.

If they woudl sell a KIT than may would is possible to use tested and approved wings and make different cockpit design ;)
 
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