What do you think about "e-soaring"?

Homebuilt Aircraft & Kit Plane Forum

Help Support Homebuilt Aircraft & Kit Plane Forum:

John.Roo

Well-Known Member
Joined
Oct 8, 2013
Messages
768
Location
Letohrad / Czech Republic
Sometimes I have opportunity to test-fly also private electric airplane projects :cool:

This is Sagitta - very light and small glider with retractable electric motor.
20201118_124120.jpg
Small means wing span of 11 m and MTOM 235 kg (max. pilot weight is 100 kg).
Battery has capacity of 6 kWh, motor has 15 kW max. power.

It was real fun to fly - like with RC model when you control it from inside :)
Sorry for not not so good video quality (especially during Take-Off) - used camera was cheap (80,-EUR) with no stabilization. Also... I didn´t used full power at the beginning of Take-Off because it was a crosswind and I never flown this plane before so I was more carefull :)
 

patrickrio

Well-Known Member
Joined
Aug 15, 2020
Messages
278
This Sagitta... by private, do you mean that a person built a single, custom design 135kg empty glider here?
 

John.Roo

Well-Known Member
Joined
Oct 8, 2013
Messages
768
Location
Letohrad / Czech Republic
This Sagitta... by private, do you mean that a person built a single, custom design 135kg empty glider here?
Practically yes.
He made his own fuselage and tail surfaces. Wing mould is very simple made as a copy of wing of old Czech glider VSO-10. In wing mould is possible to make wing with larger wing span.

Some flight tests were also done with this plane a pure glider (no propulsion)
DSCN0036.JPG
And also with engine installed on the fin
DSCN0493.JPG
DSCN0437.JPG
Interesting "toy" built by enthusiast :)
 

patrickrio

Well-Known Member
Joined
Aug 15, 2020
Messages
278
Practically yes.
He made his own fuselage and tail surfaces. Wing mould is very simple made as a copy of wing of old Czech glider VSO-10. In wing mould is possible to make wing with larger wing span.......Interesting "toy" built by enthusiast :)
Do you have physical and performance specifications? It would be interesting to see those....
 

John.Roo

Well-Known Member
Joined
Oct 8, 2013
Messages
768
Location
Letohrad / Czech Republic
Do you have physical and performance specifications? It would be interesting to see those....
I have some info :)
Dimensions are on drawing:
Sagitta 3view with engine.jpg

This is info about performance I received before test flying:
- best L/D is 1:31 at 90 kmph (valid for retractable propulsion system)
- Vne 150 kmph
- stall speed 45 kmph
- max. speed in turbulence 120 kmph

Airframe seems to be designed for higher speeds, and higher MTOM (arround 300 kg). So I suppose that reason for this numbers was simple certification :)
Aiframe and control lines are really simple - obviously was the goal to achieve low production costs.
 

John.Roo

Well-Known Member
Joined
Oct 8, 2013
Messages
768
Location
Letohrad / Czech Republic
Just say no to any type of motor glider. Flying on tow or winch is more fun.
It is about the freedom of choice.
This small glider has tow hook so you can go up to the air behind a tow plane.
I just don´t think so it was tested also for a winch start.

During working days is not always easy to find out some tow plane pilot and is practically impossible to get enough people to make a winch start.
At least in my aeroclub.
So if you can use self launch possibility you can fly when you want.
And if there is tow plane and tow pilot available you can use propulsion to get back home "in case of...".
As I wrote - is not bad to have freedom of choice :)

In case you are sure you definitelly don´t want to have self launch possibilities than you can use only small 5 kW electric motor in front (like "FES") and small folding prop as "sustainer".
Or no propulsion at all... as real "hardcore glider pilot" :cool:

DSCN0049.JPG
 

proppastie

Well-Known Member
Log Member
Joined
Feb 19, 2012
Messages
5,107
Location
NJ

noticed the elevator was not straight .....is that a weight and balance problem? probably detracts from his performance
 

964SS

Member
HBA Supporter
Joined
Feb 13, 2014
Messages
17
Location
Horton, MI, USA
It is about the freedom of choice.
This small glider has tow hook so you can go up to the air behind a tow plane.
I just don´t think so it was tested also for a winch start.

During working days is not always easy to find out some tow plane pilot and is practically impossible to get enough people to make a winch start.
At least in my aeroclub.
So if you can use self launch possibility you can fly when you want.
And if there is tow plane and tow pilot available you can use propulsion to get back home "in case of...".
As I wrote - is not bad to have freedom of choice :)

In case you are sure you definitelly don´t want to have self launch possibilities than you can use only small 5 kW electric motor in front (like "FES") and small folding prop as "sustainer".
Or no propulsion at all... as real "hardcore glider pilot" :cool:

View attachment 110496
It is about the freedom of choice.
This small glider has tow hook so you can go up to the air behind a tow plane.
I just don´t think so it was tested also for a winch start.

During working days is not always easy to find out some tow plane pilot and is practically impossible to get enough people to make a winch start.
At least in my aeroclub.
So if you can use self launch possibility you can fly when you want.
And if there is tow plane and tow pilot available you can use propulsion to get back home "in case of...".
As I wrote - is not bad to have freedom of choice :)

In case you are sure you definitelly don´t want to have self launch possibilities than you can use only small 5 kW electric motor in front (like "FES") and small folding prop as "sustainer".
Or no propulsion at all... as real "hardcore glider pilot" :cool:

View attachment 110496
I get it. Still feels like cheating when I’m flying one that has a windmill. Half the adventure is the possibility of landing out
 

John.Roo

Well-Known Member
Joined
Oct 8, 2013
Messages
768
Location
Letohrad / Czech Republic
(valid for retractable propulsion system) ?
45 kmph... well I suppose that they told me "calculated stall speed".
I personally don´t beleive so much in that slow speed (definitelly not with my weight) ;)
But I had no feeling of some "sharp" or "dangerous" flight characteristics at low speeds so for me was OK.
 

John.Roo

Well-Known Member
Joined
Oct 8, 2013
Messages
768
Location
Letohrad / Czech Republic
I get it. Still feels like cheating when I’m flying one that has a windmill. Half the adventure is the possibility of landing out
No problem :)
No propulsion = lower production cost and lower weight.
Than would be maybe not bad to add some small water balast tanks.

I definitelly prefere to have self launch.... and I am bit thinking to build one for me - just for fun.
But true is that with our 100 hp Phoenix I could tow two Sagittas at the same time ;)
 
Top