FES climb rate question.

You'll get at least 2m/s dry. But like PF says, better to take a tow to 400m and use the FES straight and level until you find a thermal. It's much more efficient in level flight than climbing.

On the Shark, based on a test flight I think that you will get less than 2m/s as it is a heavier glider than Matthew's Diana 2 :-).

From the FES manual:
5.3.4.1 Rate of climb
The maximum rate of climb is available only for a few minutes with fully charged battery packs. As battery voltage is reduced, the maximum achievable climb rate is lower. The average rate of climb depends mostly on the type of sailplane and its take-off weight. Maximum attainable altitude gain that in standard atmosphere conditions depends on the type of sailplane, its weight and aerodynamic qualities. To achieve the maximum altitude gain, use about 15kW of power. Do not use full power as the efficiency of the system is lower. Usually, 80-85 km/h is best for the climb with positive flap setting (the same setting as used while thermaling). Here are rough numbers:
•1600 m (5200 ft) for UL sailplanes at 300kg take-off weight, i.e. Silent 2 Electro
•1400 m (4500 ft) for the 18m class sailplanes at 400kg take-off weight (without water ballast), i.e.LAK17A FES
•1200 m (3900 ft) for the 18m class sailplanes at 450kg take-off weight (without water ballast); LAK17B FES, Ventus 2cxa FES, Discus 2c FES, HPH 304ES

On Thursday, October 8, 2020 at 1:14:30 PM UTC-7, Mana wrote:
You'll get at least 2m/s dry. But like PF says, better to take a tow to 400m and use the FES straight and level until you find a thermal. It's much more efficient in level flight than climbing.

On the Shark, based on a test flight I think that you will get less than 2m/s as it is a heavier glider than Matthew's Diana 2 :-).

From the FES manual:
5.3.4.1 Rate of climb
The maximum rate of climb is available only for a few minutes with fully charged battery packs. As battery voltage is reduced, the maximum achievable climb rate is lower. The average rate of climb depends mostly on the type of sailplane and its take-off weight. Maximum attainable altitude gain that in standard atmosphere conditions depends on the type of sailplane, its weight and aerodynamic qualities. To achieve the maximum altitude gain, use about 15kW of power. Do not use full power as the efficiency of the system is lower. Usually, 80-85 km/h is best for the climb with positive flap setting (the same setting as used while thermaling). Here are rough numbers:
•1600 m (5200 ft) for UL sailplanes at 300kg take-off weight, i.e.. Silent 2 Electro
•1400 m (4500 ft) for the 18m class sailplanes at 400kg take-off weight (without water ballast), i.e.LAK17A FES
•1200 m (3900 ft) for the 18m class sailplanes at 450kg take-off weight (without water ballast); LAK17B FES, Ventus 2cxa FES, Discus 2c FES, HPH 304ES

Sounds like a very marginal self-launch system and is really just a decent self-retrieve (turbo) setup.

Tom

Dne pátek 9. Å™Ã*jna 2020Â*vÂ*2:54:13 UTC+2 uživatel 2G napsal:
On Thursday, October 8, 2020 at 1:14:30 PM UTC-7, Mana wrote:
You'll get at least 2m/s dry. But like PF says, better to take a tow to 400m and use the FES straight and level until you find a thermal. It's much more efficient in level flight than climbing.

On the Shark, based on a test flight I think that you will get less than 2m/s as it is a heavier glider than Matthew's Diana 2 :-).

From the FES manual:
5.3.4.1 Rate of climb
The maximum rate of climb is available only for a few minutes with fully charged battery packs. As battery voltage is reduced, the maximum achievable climb rate is lower. The average rate of climb depends mostly on the type of sailplane and its take-off weight. Maximum attainable altitude gain that in standard atmosphere conditions depends on the type of sailplane, its weight and aerodynamic qualities. To achieve the maximum altitude gain, use about 15kW of power. Do not use full power as the efficiency of the system is lower. Usually, 80-85 km/h is best for the climb with positive flap setting (the same setting as used while thermaling). Here are rough numbers:
•1600 m (5200 ft) for UL sailplanes at 300kg take-off weight, i..e. Silent 2 Electro
•1400 m (4500 ft) for the 18m class sailplanes at 400kg take-off weight (without water ballast), i.e.LAK17A FES
•1200 m (3900 ft) for the 18m class sailplanes at 450kg take-off weight (without water ballast); LAK17B FES, Ventus 2cxa FES, Discus 2c FES, HPH 304ES
Sounds like a very marginal self-launch system and is really just a decent self-retrieve (turbo) setup.

Tom
HI
stefan langer discus capabilities of Shark FES in some of his videos, I dont remenber exact number but you can try wach it.
https://www.youtube.com/user/SLSoaring

On 10/8/20 6:54 PM, 2G wrote:
On Thursday, October 8, 2020 at 1:14:30 PM UTC-7, Mana wrote:
You'll get at least 2m/s dry. But like PF says, better to take a tow to 400m and use the FES straight and level until you find a thermal. It's much more efficient in level flight than climbing.

On the Shark, based on a test flight I think that you will get less than 2m/s as it is a heavier glider than Matthew's Diana 2 :-).

From the FES manual:
5.3.4.1 Rate of climb
The maximum rate of climb is available only for a few minutes with fully charged battery packs. As battery voltage is reduced, the maximum achievable climb rate is lower. The average rate of climb depends mostly on the type of sailplane and its take-off weight. Maximum attainable altitude gain that in standard atmosphere conditions depends on the type of sailplane, its weight and aerodynamic qualities. To achieve the maximum altitude gain, use about 15kW of power. Do not use full power as the efficiency of the system is lower. Usually, 80-85 km/h is best for the climb with positive flap setting (the same setting as used while thermaling). Here are rough numbers:
•1600 m (5200 ft) for UL sailplanes at 300kg take-off weight, i.e. Silent 2 Electro
•1400 m (4500 ft) for the 18m class sailplanes at 400kg take-off weight (without water ballast), i.e.LAK17A FES
•1200 m (3900 ft) for the 18m class sailplanes at 450kg take-off weight (without water ballast); LAK17B FES, Ventus 2cxa FES, Discus 2c FES, HPH 304ES

Sounds like a very marginal self-launch system and is really just a decent self-retrieve (turbo) setup.

Tom


These gliders are sustainers only.

On 10/12/20 8:46 AM, kinsell wrote:
On 10/8/20 6:54 PM, 2G wrote:
On Thursday, October 8, 2020 at 1:14:30 PM UTC-7, Mana wrote:
You'll get at least 2m/s dry. But like PF says, better to take a tow
to 400m and use the FES straight and level until you find a thermal.
It's much more efficient in level flight than climbing.

On the Shark, based on a test flight I think that you will get less
than 2m/s as it is a heavier glider than Matthew's Diana 2 :-).

Â*From the FES manual:
5.3.4.1 Rate of climb
TheÂ* maximum rateÂ* of climbÂ* isÂ* availableÂ* onlyÂ* forÂ* aÂ* few
minutesÂ* withÂ* fullyÂ* charged battery packs. As battery voltage is
reduced, the maximum achievable climb rate is lower. The average rate
of climb depends mostly on the type of sailplane and its take-off
weight. Maximum attainable altitude gain that in standard atmosphere
conditions depends on the typeÂ* ofÂ* sailplane,Â* itsÂ* weightÂ* and
aerodynamicÂ* qualities.Â* To achieve the maximum altitudeÂ* gain, use
aboutÂ* 15kWÂ* ofÂ* power. DoÂ* notÂ* useÂ* fullÂ* powerÂ* asÂ* the
efficiencyÂ* ofÂ* the systemÂ* isÂ* lower. Usually, 80-85Â* km/h isÂ* best
for theÂ* climb with positive flapÂ* setting (the same setting as used
while thermaling). Here are rough numbers:
•1600 m (5200 ft) for UL sailplanes at 300kg take-off weight, i.e.
Silent 2 Electro
•1400Â* m (4500Â* ft)Â* forÂ* theÂ* 18mÂ* classÂ* sailplanesÂ* atÂ* 400kg
take-off weightÂ* (without water ballast), i.e.LAK17A FES
•1200Â* mÂ* (3900Â* ft) forÂ* theÂ* 18mÂ* classÂ* sailplanesÂ* atÂ* 450kg
take-off weightÂ* (without water ballast); LAK17B FES, Ventus 2cxa
FES, Discus 2c FES, HPH 304ES

Sounds like a very marginal self-launch system and is really just a
decent self-retrieve (turbo) setup.

Tom


These gliders are sustainers only.

Looks like the Silent 2 is rated for self-launch.

kinsell wrote on 10/12/2020 11:40 AM:
On 10/12/20 8:46 AM, kinsell wrote:
On 10/8/20 6:54 PM, 2G wrote:
On Thursday, October 8, 2020 at 1:14:30 PM UTC-7, Mana wrote:
You'll get at least 2m/s dry. But like PF says, better to take a tow to 400m and use the
FES straight and level until you find a thermal. It's much more efficient in level flight
than climbing.

On the Shark, based on a test flight I think that you will get less than 2m/s as it is a
heavier glider than Matthew's Diana 2 :-).

*From the FES manual:
5.3.4.1 Rate of climb
The* maximum rate* of climb* is* available* only* for* a* few minutes* with* fully* charged
battery packs. As battery voltage is reduced, the maximum achievable climb rate is lower.
The average rate of climb depends mostly on the type of sailplane and its take-off weight.
Maximum attainable altitude gain that in standard atmosphere conditions depends on the
type* of* sailplane,* its* weight* and aerodynamic* qualities.* To achieve the maximum
altitude* gain, use about* 15kW* of* power. Do* not* use* full* power* as* the efficiency
of* the system* is* lower. Usually, 80-85* km/h is* best for the* climb with positive flap
setting (the same setting as used while thermaling). Here are rough numbers:
•1600 m (5200 ft) for UL sailplanes at 300kg take-off weight, i.e. Silent 2 Electro
•1400* m (4500* ft)* for* the* 18m* class* sailplanes* at* 400kg take-off weight* (without
water ballast), i.e.LAK17A FES
•1200* m* (3900* ft) for* the* 18m* class* sailplanes* at* 450kg take-off weight* (without
water ballast); LAK17B FES, Ventus 2cxa FES, Discus 2c FES, HPH 304ES

Sounds like a very marginal self-launch system and is really just a decent self-retrieve
(turbo) setup.

Tom


These gliders are sustainers only.

Looks like the Silent 2 is rated for self-launch.

As is the miniLak FES, also a 13.5M glider. It works well for them because they are lighter
than the 18M gliders.

--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
- "A Guide to Self-Launching Sailplane Operation"
https://sites.google.com/site/motorg...ad-the-guide-1

As is the new LAK 17c FES https://www.youtube.com/watch?v=rxe6DIfPKb4

More prop clearance, 16s batteries and higher max RPM for 2.5 m/s climb rate. The angle of attack of the wing is smaller, back to what it was on the 17a (vs the 17b that was based on the fuselage of the LAK 19)

These gliders are sustainers only.

Looks like the Silent 2 is rated for self-launch.
As is the miniLak FES, also a 13.5M glider. It works well for them because they are lighter
than the 18M gliders.

--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)

On Monday, October 12, 2020 at 3:18:05 PM UTC-5, Mana wrote:
As is the new LAK 17c FES https://www.youtube.com/watch?v=rxe6DIfPKb4

More prop clearance,

Looks like keeping the tail down is interesting at 1:30 in the video.
What does the POH ask you to do with the stick?

If you use it to hold down the tail and hit a bump, then how high can the tail bounce before entering lawn mower mode?

Technically self launch, but with grass or tiger country, the tow line didn't look all that long and having the batteries full seems wise.

Take-off performance looks impressive. I was surprised by the amount of noise - sounded not unlike a petrol engined aircraft as it passed the camera, although presumably it is actually much less loud.

Any idea what the endurance is of that aircraft?

As the owner of a petrol self-launcher, I like to know that I have enough endurance for a launch to 2,100 feet (700 m), a relight if necessary, and a reasonable self-retrieve later if necessary. I will stick to petrol until batteries can cope with at least that.