Jonker JS4 Details

Paul T

unread,

Oct 18, 2019, 12:30:06 AM10/18/19

to

https://jonkersailplanes.co.za/js4/

Paul T

unread,

Oct 18, 2019, 12:30:06 AM10/18/19

to

https://jonkersailplanes.co.za/js4/

JS

unread,

Oct 18, 2019, 1:05:51 AM10/18/19

to

On Thursday, October 17, 2019 at 9:30:06 PM UTC-7, Paul T wrote:
> https://jonkersailplanes.co.za/js4/

What happened to the self-launching 18m/21m JS2?
Jim

Paul T

unread,

Oct 18, 2019, 1:30:05 AM10/18/19

to

https://jonkersailplanes.co.za/js2/ and
https://jonkersailplanes.co.za/2019/08/16/the-js2-sl-project-update/

krasw

unread,

Oct 18, 2019, 4:40:17 AM10/18/19

to

Looks like AS34Me competitor with 20 years more recent aerodynamics, interesting. Lets see the weight the thing, especially SL electric version (not that JS would tell that, though).

Andy Blackburn

unread,

Oct 18, 2019, 5:32:56 AM10/18/19

to

JS4 has a retractable electric motor instead of FES and it can self launch.

“The JS4 will be available with the jet sustainer system as well as the new electric self-launch motor option which retracts into the fuselage for low-drag ultimate performance.“

Getting some extra mileage out of all that fuselage and wing work on the JS3. I’m guessing the electric motor might go in the JS3 as well unless the flap mixer gets in the way since it’s otherwise the same fuselage. They had been talking FES previously as an option for the JS3.

All that leaves is a high-performance two-seater - unless they want to try to crack the trainer market.

Admirable efforts.

Andy Blackburn

Paul T

unread,

Oct 18, 2019, 6:15:05 AM10/18/19

to

At 09:32 18 October 2019, Andy Blackburn wrote:
>JS4 has a retractable electric motor instead of FES and it can self
launch.
>

>=E2=80=9CThe JS4 will be available with the jet sustainer system
as well
>as=

> the new electric self-launch motor option which retracts into the

>fuselage=
> for low-drag ultimate performance.=E2=80=9C

>
>Getting some extra mileage out of all that fuselage and wing work
on the

>JS=
>3. I=E2=80=99m guessing the electric motor might go in the JS3
as well
>unle=
>ss the flap mixer gets in the way since it=E2=80=99s otherwise
the same
>fus=

>elage. They had been talking FES previously as an option for the

JS3.=20

>
>All that leaves is a high-performance two-seater - unless they want
to try

>=

>to crack the trainer market.
>
>Admirable efforts.
>
>Andy Blackburn

A JS5 is listed as a product coming in 2024?????

uneekc...@gmail.com

unread,

Oct 18, 2019, 10:41:30 AM10/18/19

to

What do they have for 13.5 M ?

Jonathan St. Cloud

unread,

Oct 18, 2019, 10:47:10 AM10/18/19

to

I would love to see Jonker's original thought on high performance two place. And if you haven't shared a flight in a high performance two place you should put that on your list. My funnest flights have been in one hole of an open two holer.

Tony

unread,

Oct 18, 2019, 11:01:57 AM10/18/19

to

Cool how long before it's in the club class range?

Dave Nadler

unread,

Oct 18, 2019, 11:04:20 AM10/18/19

to

On Friday, October 18, 2019 at 10:47:10 AM UTC-4, Jonathan St. Cloud wrote:
> My funnest flights have been in one hole of an open two holer.

Yea, I used to fly my RHJ-8 open-canopy too...

Steve Leonard

unread,

Oct 18, 2019, 1:59:47 PM10/18/19

to

The RHJ-9 flew open canopy once, too. The flight before I got it. Needed some repairs. But, that was because it started the flight with the canopy on in the normal position, and ended the flight with the canopy "on" but in a not at all normal position (stuck to the tail).

Steve Leonard

Matt McBee

unread,

Oct 19, 2019, 12:33:32 PM10/19/19

to

The JS4 website says "performance polar standard class", but then under SAFETY describes automatic control hookups for flaperons.

So... what type of sailplane is this, and how is it different from the JS3? Does it have flaps or not?

Matt

jpg...@gmail.com

unread,

Oct 19, 2019, 1:08:01 PM10/19/19

to

Differences from the JS3 - the obvious ones on the link are larger wing area and different plan-form, poorer high speed performance and no flaps on the 3 view

Paul T

unread,

Oct 20, 2019, 4:30:05 AM10/20/19

to

Errors whilst updating the website - a lot of things where different
yesterday i.e. 'open class polar' - looked like things had been copied
and pasted over from other descriptions -some links are still not
working correctly etc., the JS4 is definitely a std class machine by all
accounts.