JS-1 Handling Bad?

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Lenticular
Posts: 140
Joined: Tue Aug 01, 2017 7:29 am

JS-1 Handling Bad?

Post by Lenticular » Sat Jun 19, 2021 5:20 am

Hi,

Is there an issue with the JS-1 flight model?

I find it quite unstable, prone to stalling, and generally rather awkward at low speed.

I keep flying it back-to-back with the Antares, Diana2, and Cirrus, and all the others, while obviously different, are much better behaved than either of the JS-1.

As I write this, I did remember that I set slightly aft CoG (-1.2).

Is the JS-1 known to be unstable with ANY aft CoG?

Despite this, it still doesn't like low speed generally, and is quite difficult to maintain a constant low speed (e.g. when thermalling).

The 21m seems worse than the 18m, and both seem worse than the Antares.
G-ZULU /// LTN
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wickid
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Re: JS-1 Handling Bad?

Post by wickid » Sat Jun 19, 2021 8:26 am

What speed are you trying to fly? With some bank and full water 110 kph is really about the minimum speed it still flies.
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Lenticular
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Re: JS-1 Handling Bad?

Post by Lenticular » Sat Jun 19, 2021 11:37 am

No ballast. I was attempting to maintain 45 kts (min sink speed) in stable ridge lift.

There was "light turbulence" but otherwise nothing too extreme (wind speed/direction was constant and the ridge line fairly straight in the area it was having problems).

I think I may be under-estimating the (dynamic) stability of the flight model. Reading some information earlier on the use of flaps, it apparently makes some gliders very prone to low speed (not stall) wing drop.

Some more experimentation is required.

I had flap 5 set...
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Bre901
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Re: JS-1 Handling Bad?

Post by Bre901 » Sat Jun 19, 2021 1:40 pm

Do you have a force-feedback joystick ?
The last (and only) person I heard having low-speed handling issues with the JS1 had not.
CN: MPT — CondorUTill webpage: https://condorutill.fr/

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