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patrickrio

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Aug 15, 2020
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282
Converted for the USA

Sagitta

Wing Area?
Minimum Sink ? @ ?
Climb rate ?
Empty Weight 135 kg / 298 lbs
Gross Weight 235 kg / 518 lbs
Power 15 kW / 20 hp
Wingspan 11 m / 36 ft
Length 5.8 m / 19 ft
Best L/D 31/1 @ 90 kph / @ 56 mph
Stall 45 kph / 28 mph
VNE 150kph / 93 mph
V Turbulence 120kph / 75mph
 
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patrickrio

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Aug 15, 2020
Messages
282
What is the wing/spar construction & material on this? Material for rest of airframe?

It must be substantially different construction than the VSO 10 to have that large of a weight reduction......
 

patrickrio

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Aug 15, 2020
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282
Gekon

airframe only weight 69 kg / 152 lb without motor or battery
empty weight 85 kg / 187 lb
Gross Weight 200kg / 441 lb
wingspan 13.5 m / 44.3 ft
length 5.85 m / 19.2 ft
wing area 8.8 m square / 95 square ft

no performance stats available on website
 

John.Roo

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Joined
Oct 8, 2013
Messages
772
Location
Letohrad / Czech Republic
Converted for the USA

Sagitta

Wing Area?
Minimum Sink ? @ ?
Climb rate ?
Empty Weight 135 kg / 298 lbs
Gross Weight 235 kg / 518 lbs
Power 15 kW / 20 hp
Wingspan 11 m / 36 ft
Length 5.8 m / 19 ft
Best L/D 31/1 @ 90 kph / @ 56 mph
Stall 45 kph / 28 mph
VNE 150kph / 93 mph
V Turbulence 120kph / 75mph
I asked for more info so missing points added.

Wing Area 7,7 m2 / 83 sqft
Wing aspect ratio 15,7
Minimum Sink 0,75 m/s / 147 ft/min
Climb rate... 2,5 m/s / 492 ft/min
Empty Weight 135 kg / 298 lbs
Gross Weight 235 kg / 518 lbs
Power 15 kW / 20 hp
Wingspan 11 m / 36 ft
Length 5.8 m / 19 ft
Best L/D 31/1 @ 90 kph / @ 56 mph
Stall 45 kmph / 28 mph
VNE 150 kmph / 93 mph
Max. speed in turbulence 120 kmph / 75 mph

Climb rate *
I flown only few flights with electric propulsion....
As with every new electric airplane I was carefully watching propulsion parameters (temp, current etc.) so I don´t know climb ratio at max power because I reduced power shortly after lift-off. 2,5 m/s was easy achieve with no rising motor temperature. At full power I would expect 3 m/s plus.
 

John.Roo

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Joined
Oct 8, 2013
Messages
772
Location
Letohrad / Czech Republic
What is the wing/spar construction & material on this? Material for rest of airframe?

It must be substantially different construction than the VSO 10 to have that large of a weight reduction......
You are right - wing has only VSO-10 shape - definitelly not construction :)
Construction is typical "Schemp Hirth" system.
Carbon spare caps - top and bottom, carbon "I" main spare, glass sandwich skin... nothing really special (no pre-preg etc.).

What I would improve...
- I would definitelly use "Schempp Hirth" airbrakes like we use on Phoenix
Airbrakes.jpg
- prototype has "side stick"... not bad (my first experience with this version of control) but central stick is central stick :) however I have to admit that control lines are really simple for production.
- some small no that important design details (different instrument panel etc.)

And... wing span :)
I was OK with 11 m, but could be possible to use system of different wing extensions like we typically use on Phoenix. Maybe 13 m version... 15 m... :) But it also means more complicated construction and higher weight... so I have to think about this :)

Generally....
Fun to fly. With this weight is possible to use small motor and small battery.
Low weight = easy certification / registration.
So most important is.... (what a surprice)... "affordable" final price :)
Similar planes (Silent, GP, Apis...) have higher performance and also high price (from my personal point of view).
With "right" price I could imagine this plane as interesting entry level electric self launch glider.
 

patrickrio

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Aug 15, 2020
Messages
282
So, for the wing shape, he used molds off of the VSO-10 and cut the wing skin shape short at the roots??
 

John.Roo

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Joined
Oct 8, 2013
Messages
772
Location
Letohrad / Czech Republic
So, for the wing shape, he used molds off of the VSO-10 and cut the wing skin shape short at the roots??
Yes, he used wing of VSO-10 to make a simple moulds.
Moulds are "original" size and idea was to to have possibility to increase wing span in case is requested.
UL/LSA rules changed a lot in EU. Now we can make even one seater with MTOM 600 kg. However in this case was a goal to achieve low EW without expensive technology and materials. And I agree - German 120 kg EW class or UK deregulated one seater class are small but interesting markets.
 

ypsilon

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Mar 1, 2016
Messages
291
Location
Austria
Gekon

airframe only weight 69 kg / 152 lb without motor or battery
empty weight 85 kg / 187 lb
Gross Weight 200kg / 441 lb
wingspan 13.5 m / 44.3 ft
length 5.85 m / 19.2 ft
wing area 8.8 m square / 95 square ft

no performance stats available on website
Darek quotes an L/D of about 30. Vne is 160 km/h.
 

John.Roo

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Oct 8, 2013
Messages
772
Location
Letohrad / Czech Republic
I don´t know exact rules for UL airplanes in Poland, but I suppose they are similar with CR so Darek did a good think to don´t set Vne too high.
In CR is actually most important to achieve lowest possible stall speed.
If you stay under 65 kmph at MTOM 300-315 kg you can stay with Vne below 200 kmph = no required flutter test.

Theoretically we can go much higher with MTOM (max. 600 kg) and also with stall speed (max. 83 kmph with flaps). But than you are facing higher certification requirements.
 

patrickrio

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Aug 15, 2020
Messages
282
I suspect that the Sagitta stall speed might have been measured on the glider, not the motorglider version, and that it was measured with a very light pilot.

And/or it has some really effective airfoils and flaps.

45 kph / 28 mph stall with 7.7 sq m / 83 sq ft wing area and 235 kg / 518lb gross wieght would be a very spectacular result, far from normally achieved.
 

John.Roo

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Joined
Oct 8, 2013
Messages
772
Location
Letohrad / Czech Republic
I suspect that the Sagitta stall speed might have been measured on the glider, not the motorglider version, and that it was measured with a very light pilot.

And/or it has some really effective airfoils and flaps.

45 kph / 28 mph stall with 7.7 sq m / 83 sq ft wing area and 235 kg / 518lb gross wieght would be a very spectacular result, far from normally achieved.
I totally agree.
I would prefere to declare that is below 65 kmph :)
 
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