Stall spin during aero tow? Std cirrus

Make sure when your briefing the tuggie that you speaking the same language ie. KNOTS or MPH. There a fair difference between 60 mph and 60 knots. If the tuggie isnt on the same page with you, you might end up in the sagebrush at the end of the runway.

On Wednesday, August 8, 2018 at 1:18:26 PM UTC+1, PGS wrote:
On Tuesday, August 7, 2018 at 10:45:24 AM UTC-4, Steve Koerner wrote:
This subject comes up every few years on RAS and that's a very good thing. Long ago there was a death on tow with a heavily watered ship that I'm pretty sure was caused by this.

I have already posted a couple times in the past about my own near death experiences I have had dangling from a slow towplane at a remarkably low stalled tow position while slamming the stick back and forth against the stops in Ventus 1 and in ASW27. When this is happening at a very low altitude (as it was), then releasing is not an option.

Several have pointed up the necessity of communicating with the tow pilot. I think it preferable to communicate in writing. Except at contests, I always make sure that the tow pilot has been handed my written towing instruction when I have water ballast. Here's a link to my little towing instruction sheet: https://goo.gl/PwVu71

Steve, you should not assume the tow planes airspeed indicator is calibrated or accurate. You might consider modifying your note to say "minimum" or "at least" and once safely on tow ask to slow down if need be.

Even if the tug ASI is properly calibrated by ground testing it may not read accurately in flight because of very poor static inputs or the use of cockpit static. As an ex JS1c 21m owner I got into the habit of not only telling tow pilots the speed I wanted (absolute minimum of 70 knots as read by the glider ASI) but also exchanging ASI readings with them on tow. Every Pawnees I was towed by had an ASI that over-read by 5-7 knots compared to my reading. The same was found using other types of glider behind Pawnees. The Eurofox tugs that are getting popular in the UK has similar errors.

I think that this may be a significant safety issue.

Although perhaps not widely used in the US, Chipmunks and Robins seemed to me to have much more accurate ASI systems.

I tell our newer towpilots that with the big gliders and gliders with water, it is almost impossible to tow them too fast and way better to be on the fast side than the slow side.

This of course is the opposite from towing slow speed trainers which are much happier slower than faster. These are what our towpilots usually tow, so when the Nimbus 3 full of water is pulled out to the line, they need to shift from a slow bias to a fast bias.

On Wednesday, August 8, 2018 at 5:18:26 AM UTC-7, PGS wrote:
On Tuesday, August 7, 2018 at 10:45:24 AM UTC-4, Steve Koerner wrote:
This subject comes up every few years on RAS and that's a very good thing. Long ago there was a death on tow with a heavily watered ship that I'm pretty sure was caused by this.

I have already posted a couple times in the past about my own near death experiences I have had dangling from a slow towplane at a remarkably low stalled tow position while slamming the stick back and forth against the stops in Ventus 1 and in ASW27. When this is happening at a very low altitude (as it was), then releasing is not an option.

Several have pointed up the necessity of communicating with the tow pilot. I think it preferable to communicate in writing. Except at contests, I always make sure that the tow pilot has been handed my written towing instruction when I have water ballast. Here's a link to my little towing instruction sheet: https://goo.gl/PwVu71

Steve, you should not assume the tow planes airspeed indicator is calibrated or accurate. You might consider modifying your note to say "minimum" or "at least" and once safely on tow ask to slow down if need be.

Another way to calibrate the speed, tell the tug to tow you as he would tow the operation's SGS 2-32.

On Wednesday, August 8, 2018 at 10:12:15 AM UTC-4, Jonathan St. Cloud wrote:
Another way to calibrate the speed, tell the tug to tow you as he
would tow the operation's SGS 2-32.

Just last week somebody reminded me of a 2-32 stall-spin off tow
near here (several decades ago).

That is why all the operators will make sure the tow pilots know it is important tow the 2-32 at the correct speed. “Tow me at the same speed as you tow the 2-32�. If anything you will ask the tug to slow down

On Wednesday, August 8, 2018 at 2:42:39 PM UTC-5, Jonathan St. Cloud wrote:
That is why all the operators will make sure the tow pilots know it is important tow the 2-32 at the correct speed. “Tow me at the same speed as you tow the 2-32�. If anything you will ask the tug to slow down

Not too many 2-32s outside the USA (too bad - love that glider). As far as Pawnees, expect (again, in the US) it to have an airspeed indicator in MPH (or perhaps a dual-scale ASI), so give him your tow speed in MPH, regardless of what you have in your glider. Better for him to tow you in MPH numbers on a Knots ASI than the reverse!

And if the Pawnee about to tow you in your 11 psf waterlogged glass ship has one notch of flaps down - don't hook up until he brings them up! That's only needed for 1-26s and K-13s (lets a Pawnee tow nicely at 65-70 mph) and a possible sign that the tuggie is not quite on the ball...

Pawnee statics = cockpit static, usually. Airspeed a bit lower and altitude a bit higher in my experience, but not by much (5 mph / 100 ft)

Kirk