ASK21 Glider aerobatics

[clearfinalsno1]

Hi

Does anyone know what if any limitations there are on doing aerobatics in an ASK21 (Alexander Schleicher K21) glider? I believe it is ok to do loops but I thought I had seen a manufacturer placard that aileron roles and other manoeuvers are prohibited? That said, I have seen many videos of (very good) aero displays in the said glider:

e.g. ASK 21 aeros video on youtube

Finally, I expect I am not the first to ask why is there no section on PPRUNE dedicated to gliding?

Thanks

CFN1

[vihai]

As far as I remember from the POH, the ASK21, once registered in A (Aerobatic) catogory, provided with 5-point seat belts, pedals straps and a g-meter, is cleared for most aerobatic maneuvers, excluding inverted loops, tail slides and snap rolls.

It is cleared for sure for loop, fiesler, airleon roll, lazy eight, chandelle, inverted flight.

It is cleared for intentional spin even in "U" (utility) category.

I routinely flight on a aerobatic ASK-21, but I'm not (yet ) rated for aerobatic manouvers

[ProfChrisReed]

The ASK21 is cleared for spins, but in unmodified configuration is unlikely to spin unless the CG is unusually far aft - this tends to mean pilots right on the minimum weight limit. For most pilot configurations, it will only drop a wing and then fall into a spiral dive. I only know one person who claims to have spun an unmodified ASK21, but many (including me) who have tried and failed.

For intentional spinning Schleicher offer a spin kit which, as I understand it, is some carefully calculated lead bolted to the tail. With that kit, again not from personal experience, I read that prolonged spins tend to flatten into an oscillatory mode, and that recovery at the nose high position can be slow.

I have experienced ASK21 aerobatics as P2, not handling pilot, and it appeared to me to be capable of quite a wide range of ways of connecting my earlobes with my hips.

I don't know if aerobatic manoeuvres other than spins are permitted with the spin kit fitted. The aircraft was designed as a spin-resistant trainer.

[tigerbatics]

Have a look at the BAeA web site and the Dan Smith Trophy sequences. This is a glider aerobatic competition which is flown in the K21. No other types are permitted. All the standard level figures are ok although a slow roll is also permitted but this is an intermediate level figure in a glider.

[clearfinalsno1]

Thanks for that guys - interesting stuff.

Sorry for another dumb question, but in the video I posted above, what is the manoever he is doing from about 2:05 to 2:20 ? It starts from inverted flight, but it looks like he is then going backwards but its not a tailslide!

[astir 8]

Re the other opening question - why is there no separate gliding-only section on PPrune?

As a glider pilot I find that the interraction between gliding and light power flying which arises in "Private Flying" can be very informative for both sets of pilots. Separation is really the last thing required. There are already dedicated websites such as gliderpilot.net

[tigerbatics]

At the point you mention in the video the glider is doing an outside turn. Same as a normal turn but with the glider inverted. He is using left aileron and right rudder.

[Rocket2]

K21 is stressed to +6 -3g as far as I recall (waiting for flack) - I regularly aerobat them & they are cleared for most manouvres including inverted manouvres. Spinning is not possible in most cases - however the Oxford University K21 (GAM) at Bicester will (or used to before I stopped flying there) with a light pilot or two in it, quite impressive but it went flat quickly & I never pushed it further than a couple of turns.
I suspect though that even a stock K21 will spin if you try it at 300ft
Safe flying
R2

[larssnowpharter]

Again, from memory, K21 will do areos but is pretty heavy with a slow roll rate.

Never did get one to spin.

I suspect though that even a stock K21 will spin if you try it at 300ft

Once demonstrated to a prospective instructor that you could fly a K21 in what was a stalled condition for a full circuit just easing the stick forward for landing because of the huge rate of sink. More like parachuting than gliding.

Keep a K13 or K7 in the club for teaching spin recovery.

[Mark1234]

Or better still, a puchacz - that spins properly.

K21's are very strong, and as noted a little lacking in control area.. they have a high Vne (151kts from memory) and a draggy wing that makes keeping the speed down quite reasonable. It's quite a decent thing to learn aeros in. My introduction was in a K13. Never felt truly comfortable about that.

The puch on the other hand has lots of control surface, is cleared for flicking but is rather slippery and has a low vne, making speed control rather important..

[Rocket2]

Hi Mark
"Or better still, a puchacz - that spins properly"
If you want to try a real spinner PM me for a go in a DG1000 - fun or what It flicks rather impressively too in small wing mode.
PS I agree about the Putch tho - have many hours in them.
Blue skies
R2

[GliderJ15]

R2

Are your bits realinged or are you still in the Wilthsire home for the bewildered?

Lots of love from the Ministry Roof

[Rocket2]

Still there J15