ASW 20 Handling Issues?

The ASW 20 seems to have a reputation for bad behavior in some configurations. Is this reputation deserved or overblown? What has been the experience of those who have owned and flown the glider? Are some variants of the 20 better or worse in terms of handling characteristics?

Tom A

I used to fly an ASW20C (15 m, no winglets) with an aft CoG, and it would spin without any warning. Mowing the CoG forward removed this behavior.
Lateron I owned an ASW20 (A-model with winglets) wich I flew with a 1/3 aft position, and it was completely harmless.

Bert TW

On Sat, 04 Nov 2017 22:55:39 -0700, anklam2 wrote:

The ASW 20 seems to have a reputation for bad behavior in some
configurations. Is this reputation deserved or overblown? What has
been the experience of those who have owned and flown the glider? Are
some variants of the 20 better or worse in terms of handling
characteristics?

I had an early ASW-20 (s/n 34), the so-called A series, with the two
stage landing flap. Twice it departed in a thermal turn without any
warning, zero flap (position 3) 40-45 degree bank, flying at 45 kts. Both
times It recovered after a 1/4 turn, though 300 ft lower and now at 80
kts. The second time it happened I tried to reproduce the same behaviour
after arriving back home in late afternoon with plenty of height in hand,
but was unable to get it to spin similar from turns at the same or a
slightly lower airspeed. I was forced to conclude that this was either
idiosyncratic behaviour of my particular ASW-20 or it had something to do
with micro-turbulence in the thermal.

Apart from that I had no issues with its handling once I'd learnt to fly
a flapped glider properly and not to add 5 kts to approach speed for luck
since that made it want to float into the next county after rounding out.


--
martin@ | Martin Gregorie
gregorie. | Essex, UK
org |

On Sunday, November 5, 2017 at 1:55:40 AM UTC-4, wrote:
The ASW 20 seems to have a reputation for bad behavior in some configurations. Is this reputation deserved or overblown? What has been the experience of those who have owned and flown the glider? Are some variants of the 20 better or worse in terms of handling characteristics?

Tom A

The '20 got a poor early reputation due to it's spin characteristics when flown with aft CG. When it came out it was very common for pilots to fly with far aft CG to try to get more performance.
I have extensive experience in A and C versions. Something around 1200 hrs or so. When flown at, or aft of the manufacturer's aft CG point they both depart and spin quite quickly. A pilot can be easily surprised by this.
That characteristic does not surface, from my experience, with the CG forward of the 80% point. It will still spin, but doesn't snap the same way. Flown well behind manufacturer's limit, is, in my opinion, very dangerous.
There is negligible performance lost at 75-80% and interestingly enough, the trimmer isn't even needed. I flew my 20C with the trimmer taped off the entire time I owned it.
I also found that external seals, in addition to the usual internal seals, seems to make the tendency to drop a wing at high angles of attack less. I'm pretty sure this is due to spanwise flow in the trailing edge cove that gets trapped by the seals.
Winglets, again from my experience, make the stall and wing drop more docile, but make the spin, as it develops, more abrupt.
There is a reason these ships have remained popular and desirable.
FWIW
UH

On Sat, 4 Nov 2017 22:55:39 -0700 (PDT), wrote:

The ASW 20 seems to have a reputation for bad behavior in some configurations. Is this reputation deserved or overblown? What has been the experience of those who have owned and flown the glider? Are some variants of the 20 better or worse in terms of handling characteristics?


I've got extensive experience in the ASW-20L and a little in an
ASW-20C.

My club's 20L was ok before it got a refinishing which resultetd in a
slioghtly sharper leading edge of the wing (and significantly
increased performance).
Before the refinishing, it would slightly drop a wing but that wasn't
worse than in any other glider of that time. After that, it could
enter a spin if stalled in flaps 4 and a slightly aft CG if you didn't
catch the dropping wing immediately.

Not visious, but it needed a little attention.

On the other hand, I've also flown a privately owned ASW-20C that was
extremely harmless and could be thermalled at less than 80 kp/h
without the slightest tendency to drop a wing.

In my opinion the flight characteristics of the ASW-20 are mostly
definied by the form of the leading edge of the wing and reports about
bad reputation are grossly overblown. In the 600 hrs I have on the 20
I had no a single unexpected departure.

My club operated the ASW-20L for 15 years where any pilot with more
than 100 hrs total flight time could fly it, and to my knowledge there
was never a serious spin incident. We sold it accident-free.

Disclaimer:
Of the 60+ different glider types I have flown so far, to me the 20
still has best flying characteristics.

On Saturday, November 4, 2017 at 10:55:40 PM UTC-7, wrote:
The ASW 20 seems to have a reputation for bad behavior in some configurations. Is this reputation deserved or overblown? What has been the experience of those who have owned and flown the glider? Are some variants of the 20 better or worse in terms of handling characteristics?

Tom A

Thanks for all the responses; very helpful.
Tom A

On Sunday, November 5, 2017 at 12:55:40 AM UTC-5, wrote:
The ASW 20 seems to have a reputation for bad behavior in some configurations. Is this reputation deserved or overblown? What has been the experience of those who have owned and flown the glider? Are some variants of the 20 better or worse in terms of handling characteristics?

Tom A

Second what the others have said about spins with the CG too far back. I have 20a serial #18. With full thermalling flap (actually hardly ever needed).. Mine will drop a wing upon stall. Just a normal wing drop that can be countered with forward stick and a bit of opposite rudder. Essentially identical behavior to my 301 Libelle with full positive flap. So, nothing abnormal for early high performance gliders.

After slipping my 301 to landings for the last 20 years, I love the 20's glide path control. Full landing flaps and full divebrakes make for parachute steep landings. However, landing flaps on the 20a can lead to trouble for the incautious. One has to be absolutely sure of having the landing site made, especially in full landing flap. Not advisable to move the landing flap handle once established on short final. Coming out of full flap will cause the glider to drop in hard, or worse, lead to a stall/spin if one pulls back to try to stop the fall.

Interesting thoughts about a glider that has been around--and much loved--since the late 1970s. I have less than 10 hours in two ASW 20s (a very early one and a later A) so I can't speak from experience. When it began to develop a bit of a reputation back in the 1980s, I heard a story/rumor/speculation that the fabric tape used to cover the flap/wing joint might be to blame if it bulged out into the airflow during slow flight and triggered separation. No idea if that was true but subsequent models used Mylar seals (and/or beryllium copper for at least one ASW 20B) and I suspect most early models have been fitted with Mylar. If I were buying a '20, I'd look at the seals--and CG--closely just to be careful.

Chip Bearden

On Sunday, November 5, 2017 at 2:23:24 PM UTC-5, wrote:
...I heard a story/rumor/speculation that the fabric tape used to cover
the flap/wing joint might be to blame if it bulged out into the airflow
during slow flight and triggered separation.

IIRC that tape bulging caused aileron flutter, but not other problems.
Regardless, the tape should have been replaced with mylar on all 20's.
Hank???

On Sunday, November 5, 2017 at 2:44:28 PM UTC-5, Dave Nadler wrote:
On Sunday, November 5, 2017 at 2:23:24 PM UTC-5, wrote:
...I heard a story/rumor/speculation that the fabric tape used to cover
the flap/wing joint might be to blame if it bulged out into the airflow
during slow flight and triggered separation.

IIRC that tape bulging caused aileron flutter, but not other problems.
Regardless, the tape should have been replaced with mylar on all 20's.
Hank???

Flutter was associated with seal tapes. Flaps fluttered more than ailerons if I remember correctly. Mylar is a good improvement and was standard on B and C. Flaps on A go down far enough to be tough on Mylar on bottom when in full landing flap.
UH