JS3 spins

[Jonathan St. Cloud]

https://www.youtube.com/watch?v=NACTj3A6-l0&fbclid=IwAR1F7UbdlNKesXWXo9vghaM7xdMtjWjRyEhPMT26U 9R2lgPoDgVInNY1mcE

Interesting that on the second turn the glider gets nose high. I have spun 2-32, K-21, ASW-24, North American SNJ-5, Ventus 2c, Nimbus 4 (quarter turn only), citabria, champ, Decathlon, maybe something else but I have never had the nose go above horizon. Can anyone tell of their experiences in a spin like this. The two most interring things I have had happen was one particular 2-32 would do an over the top spin enter from a deep slip and another would go from spin to spiral by itself.

[Jonathan St. Cloud]

On Saturday, October 26, 2019 at 10:50:26 AM UTC-7, Jonathan St. Cloud wrote:
> https://www.youtube.com/watch?v=NACTj3A6-l0&fbclid=IwAR1F7UbdlNKesXWXo9vghaM7xdMtjWjRyEhPMT26U 9R2lgPoDgVInNY1mcE
>
> Interesting that on the second turn the glider gets nose high. I have spun 2-32, K-21, ASW-24, North American SNJ-5, Ventus 2c, Nimbus 4 (quarter turn only), citabria, champ, Decathlon, maybe something else but I have never had the nose go above horizon. Can anyone tell of their experiences in a spin like this. The two most interring things I have had happen was one particular 2-32 would do an over the top spin enter from a deep slip and another would go from spin to spiral by itself.

Piper Super Cub was the other aircraft I had spun without ever having the nose point above horizon. I have had oscillations but nothing like the second turn of the JS3. Would like to understand a bit more about this an if there are techniques to keep the nose from going high other than recover sooner. Any shared experiences or comments welcomed.

[James Ewence]

I understand a number of high performance gliders show this
characteristic.

I have personally observed the DG1000 which spins like this very
prominently with the nose oscillating above and below the horizon,
inputting the recovery actions when the nose is above the horizon
seems to delay the recovery.





At 17:55 26 October 2019, Jonathan St. Cloud wrote:
>On Saturday, October 26, 2019 at 10:50:26 AM UTC-7, Jonathan
St. Cloud
>wrot=
>e:
>>
>https://www.youtube.com/watch?v=3DNACTj3A6-
l0&fbclid=3DIwAR1F7UbdlNKesXWX=
>o9vghaM7xdMtjWjRyEhPMT26U9R2lgPoDgVInNY1mcE
>>=20
>> Interesting that on the second turn the glider gets nose high. I
have
>sp=
>un 2-32, K-21, ASW-24, North American SNJ-5, Ventus 2c, Nimbus
4 (quarter
>t=
>urn only), citabria, champ, Decathlon, maybe something else but I
have
>neve=
>r had the nose go above horizon. Can anyone tell of their
experiences in
>a=
> spin like this. The two most interring things I have had happen
was one
>p=
>articular 2-32 would do an over the top spin enter from a deep slip
and
>ano=
>ther would go from spin to spiral by itself.
>
>Piper Super Cub was the other aircraft I had spun without ever
having the
>n=
>ose point above horizon. I have had oscillations but nothing like
the
>seco=
>nd turn of the JS3. Would like to understand a bit more about this
an if
>t=
>here are techniques to keep the nose from going high other than
recover
>soo=
>ner. Any shared experiences or comments welcomed.
>

[[email protected]]

On Saturday, October 26, 2019 at 6:55:34 PM UTC+1, Jonathan St. Cloud wrote:
> On Saturday, October 26, 2019 at 10:50:26 AM UTC-7, Jonathan St. Cloud wrote:
> > https://www.youtube.com/watch?v=NACTj3A6-l0&fbclid=IwAR1F7UbdlNKesXWXo9vghaM7xdMtjWjRyEhPMT26U 9R2lgPoDgVInNY1mcE
> >
> > Interesting that on the second turn the glider gets nose high. I have spun 2-32, K-21, ASW-24, North American SNJ-5, Ventus 2c, Nimbus 4 (quarter turn only), citabria, champ, Decathlon, maybe something else but I have never had the nose go above horizon. Can anyone tell of their experiences in a spin like this. The two most interring things I have had happen was one particular 2-32 would do an over the top spin enter from a deep slip and another would go from spin to spiral by itself.
>
> Piper Super Cub was the other aircraft I had spun without ever having the nose point above horizon. I have had oscillations but nothing like the second turn of the JS3. Would like to understand a bit more about this an if there are techniques to keep the nose from going high other than recover sooner. Any shared experiences or comments welcomed.

Its the same with the JS1. I doubt that you can prevent that by anything you do from inside the cockpit and it doesn't affect the conventional spin recovery. As two types have completely different fuselages and wing mounting positions I guess it is a characteristic of the shared T12 airfoil and the very similar planforms (the JS3 wing being derived from the outer almost 9m of the JS1c 21 wing).

[Andy Blackburn[_3_]]

Think of the aircraft spinning about its velocity vector in a bending corkscrew kind of motion as the velocity vector transitions from horizontal to vertical. I would expect that the higher performance gliders will take longer for the velocity vector to arc over and so the change in orientation of the nose relative to the horizon will be more extreme - depending on a whole host of factors - starting velocity, c.g., etc.

My ASW-27 definitely oscillates relative to the horizon on the first turn, but the nose doesn't get above the horizon like the JS3. Good thing to know.. You don't want to get disoriented in the recovery. Here's a look, the first spin shows the nose approaching, but not going above the horizon.

https://youtu.be/9aDJLDQ-5QU

Andy Blackburn
9B

On Saturday, October 26, 2019 at 10:55:34 AM UTC-7, Jonathan St. Cloud wrote:
> On Saturday, October 26, 2019 at 10:50:26 AM UTC-7, Jonathan St. Cloud wrote:
> > https://www.youtube.com/watch?v=NACTj3A6-l0&fbclid=IwAR1F7UbdlNKesXWXo9vghaM7xdMtjWjRyEhPMT26U 9R2lgPoDgVInNY1mcE
> >
> > Interesting that on the second turn the glider gets nose high. I have spun 2-32, K-21, ASW-24, North American SNJ-5, Ventus 2c, Nimbus 4 (quarter turn only), citabria, champ, Decathlon, maybe something else but I have never had the nose go above horizon. Can anyone tell of their experiences in a spin like this. The two most interring things I have had happen was one particular 2-32 would do an over the top spin enter from a deep slip and another would go from spin to spiral by itself.
>
> Piper Super Cub was the other aircraft I had spun without ever having the nose point above horizon. I have had oscillations but nothing like the second turn of the JS3. Would like to understand a bit more about this an if there are techniques to keep the nose from going high other than recover sooner. Any shared experiences or comments welcomed.

[[email protected]]

Nice video, I miss minden. You probably need to hold her in that spin a little longer, another turn to see if the oscillations set up with a nose high pitch. I know when I had the 2-32, if I had someone of lighter weight in the front seat, the spin would oscillate pretty markedly after the first rotation. Prob due to a more rearward cg.

Incidentely, she would snap into an over the top spin readily even from a strong slip if she was aggravated into it.

[Richard DalCanto]

On Saturday, October 26, 2019 at 11:50:26 AM UTC-6, Jonathan St. Cloud wrote:
> https://www.youtube.com/watch?v=NACTj3A6-l0&fbclid=IwAR1F7UbdlNKesXWXo9vghaM7xdMtjWjRyEhPMT26U 9R2lgPoDgVInNY1mcE
>
> Interesting that on the second turn the glider gets nose high. I have spun 2-32, K-21, ASW-24, North American SNJ-5, Ventus 2c, Nimbus 4 (quarter turn only), citabria, champ, Decathlon, maybe something else but I have never had the nose go above horizon. Can anyone tell of their experiences in a spin like this. The two most interring things I have had happen was one particular 2-32 would do an over the top spin enter from a deep slip and another would go from spin to spiral by itself.

I wonder if it is has anything to do with the fact that he is keeping the stick all the way back into the second turn. In real life, you would release back pressure as soon as the spin started to recover as soon as possible.

[Charlie Quebec]

I’ve had the nose oscillate up and down in a spin in a DG 1000, as the nose comes up, the rate of rotation slows, then speeds up again as the nose drops.
Conventional wisdom is the T tail is going in and out of the wing wake causes this.

[[email protected]]

Remember, the glider is flying level before the rotation starts. Books show aircraft descending vertically at departure but in reality the rotation starts along the original flight path. This is why from the cockpit it appears to be a nose high oscillation. Once the glider loses it's forward momentum it descends vertically and the view from the cockpit becomes normal without the apparent oscillation.

[Tango Whisky]

No. A Discus b would keep this oscillation with the nose coming up above the horizon all the way down to impact.

[[email protected]]

On Saturday, October 26, 2019 at 7:38:31 PM UTC-4, Richard DalCanto wrote:
> On Saturday, October 26, 2019 at 11:50:26 AM UTC-6, Jonathan St. Cloud wrote:
> > https://www.youtube.com/watch?v=NACTj3A6-l0&fbclid=IwAR1F7UbdlNKesXWXo9vghaM7xdMtjWjRyEhPMT26U 9R2lgPoDgVInNY1mcE
> >
> > Interesting that on the second turn the glider gets nose high. I have spun 2-32, K-21, ASW-24, North American SNJ-5, Ventus 2c, Nimbus 4 (quarter turn only), citabria, champ, Decathlon, maybe something else but I have never had the nose go above horizon. Can anyone tell of their experiences in a spin like this. The two most interring things I have had happen was one particular 2-32 would do an over the top spin enter from a deep slip and another would go from spin to spiral by itself.
>
> I wonder if it is has anything to do with the fact that he is keeping the stick all the way back into the second turn. In real life, you would release back pressure as soon as the spin started to recover as soon as possible.

This is not "real life". Certification testing is trying to determine if the aircraft will recover conventionally from a fully developed(multi turn) spin.
UH

[[email protected]]

On Sunday, October 27, 2019 at 1:23:11 AM UTC, wrote:
> Remember, the glider is flying level before the rotation starts. Books show aircraft descending vertically at departure but in reality the rotation starts along the original flight path. This is why from the cockpit it appears to be a nose high oscillation. Once the glider loses it's forward momentum it descends vertically and the view from the cockpit becomes normal without the apparent oscillation.

That is not true in theory nor is it what the video shows in practice. Look at the external view starting at 1:24. As the JS3 auto-rotates the it also yaws down to the vertical then the nose rises to above the horizontal after 360 degrees of spin rotation.

[John Seaborn (A8)]

What Hank said, its certification test flying. I have purpose spun my JS3 several times with aft CG and it never exhibited the pitching action shown in the video. It spins beautifully and immediately recovers with the normal recovery control inputs. I applaud the factory for making these videos available as they give some insight into the handling and testing of the glider and they are fun to watch - full spoiler at redline. Ouch.
A8

[Tango Whisky]

By definition, you can enter a spin, and you can exit a spin.
You can't control what happens inbetween.