A aviation & planes forum. AviationBanter

If this is your first visit, be sure to check out the FAQ by clicking the link above. You may have to register before you can post: click the register link above to proceed. To start viewing messages, select the forum that you want to visit from the selection below.

Go Back   Home » AviationBanter forum » rec.aviation newsgroups » Soaring
Site Map Home Register Authors List Search Today's Posts Mark Forums Read Web Partners

Stall spin during aero tow? Std cirrus



 
 
Thread Tools Display Modes
  #41  
Old August 8th 18, 03:04 PM posted to rec.aviation.soaring
Dave Nadler
external usenet poster
 
Posts: 1,300
Default Stall spin during aero tow? Std cirrus

On Tuesday, August 7, 2018 at 9:34:10 PM UTC-4, Tom BravoMike wrote:
On Tuesday, August 7, 2018 at 8:42:40 PM UTC-4, Dave Nadler wrote:
On Tuesday, August 7, 2018 at 7:01:38 PM UTC-4, Tom BravoMike wrote:
How come nobody mentions positive faps in this discussion?
Am I missing sth? Are they useless in situations when the tug is too slow?
If so, why? Please illuminate me.


Flaps add a lot of drag. The first time I had a stall on tow,
I pulled down landing flaps, which recovered the stall and
almost put the towplane in the trees. I eased off the flap
and somehow he sped up without hitting anything.
Please do not try this at home.

Be safe out there,
Best Regards, Dave

PS: I think flaps do have the benefit of improving the lift
distribution on tow, which slightly compensates for the bad effects.


OK, so we are talking here 'nothing or everything'. Landing flaps are
on the extreme end. The Ventus manual tells you to go from '0' to '+1'
on take off if necessary (eg. with water). And yes, it does depend how
much extra power the tow plane has. The golden middle rule applies...


I was already at flaps +2 due to inadequate tow speed, L is next step...
Certainly not "all or nothing"...
Ads
  #42  
Old August 8th 18, 03:12 PM posted to rec.aviation.soaring
Jonathan St. Cloud
external usenet poster
 
Posts: 1,027
Default Stall spin during aero tow? Std cirrus

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.
  #43  
Old August 8th 18, 06:37 PM posted to rec.aviation.soaring
Dave Nadler
external usenet poster
 
Posts: 1,300
Default Stall spin during aero tow? Std cirrus

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).
  #44  
Old August 8th 18, 08:42 PM posted to rec.aviation.soaring
Jonathan St. Cloud
external usenet poster
 
Posts: 1,027
Default Stall spin during aero tow? Std cirrus

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
  #45  
Old August 8th 18, 09:24 PM posted to rec.aviation.soaring
kirk.stant
external usenet poster
 
Posts: 1,230
Default Stall spin during aero tow? Std cirrus

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
  #46  
Old August 8th 18, 10:11 PM posted to rec.aviation.soaring
Charlie M. (UH & 002 owner/pilot)
external usenet poster
 
Posts: 1,017
Default Stall spin during aero tow? Std cirrus

General comment, not totally related to this post.........
Most of our tug pilots are also glider pilots, tug pilot is sorta secondary.
We usually fly dry, but if we fly wet, we (glider pilot) instruct wing runner to flag tuggie that we are wet and need more speed.
I have flown out of our field heavy (ASW-20 a and c, thus 9lbs......) before with no issues.
Don't know if our field has EVER had a 2-32, I have flown a lot of ships, a 2-32 is not on the list.

Yes, a wee bit fast is better than a wee bit slow. I am a light pilot and have done XC tows from home to HHSC in a 1-26 (something like 120 air miles), yep, things got a wee bit too fast, but we were racing November weather to destination.

If you bend/break something, have a good reason when the FAA comes calling.
Hopefully you are around to chat with them.
Radios can fail or get stepped on.

Flapped ships have some options, but not unlimited.
Nonflapped have few options.
Time for go/no go is limited. When in doubt, bail out.
  #47  
Old August 9th 18, 05:17 AM posted to rec.aviation.soaring
GliderCZ
external usenet poster
 
Posts: 1
Default Stall spin during aero tow? Std cirrus


Hi sorry for the thread creep
I have just Changed to a Ventus 2c after 1500 without flaps.
As briefed I roll in negative flap and change to +2 when I am sure that I
have aileron control.The tug pilot knows all this and tows me at 70+knts.
Am I now at the flap limit for positive flaps?
Last flight I was happy up to 70 but above I chose to go to 0.
Jon


Limit for any positive flap setting on V2C is 86 knots, Vfe per flight manual. Typical takeoff starts at -1, going to 0 as you get aileron authority, then +1 as you approach takeoff and throughout the tow. That's always worked for me. Takeoff and tow at+2 always required too much forward stick for me. YMMV. I think you'll enjoy the V2C. Great xc ship!

  #48  
Old August 9th 18, 08:11 AM posted to rec.aviation.soaring
Jonathon May[_2_]
external usenet poster
 
Posts: 88
Default Stall spin during aero tow? Std cirrus

At 04:17 09 August 2018, GliderCZ wrote:

Hi sorry for the thread creep
I have just Changed to a Ventus 2c after 1500 without flaps.
As briefed I roll in negative flap and change to +2 when I am

sure that I
have aileron control.The tug pilot knows all this and tows me at

70+knts.
Am I now at the flap limit for positive flaps?
Last flight I was happy up to 70 but above I chose to go to 0.
Jon


Limit for any positive flap setting on V2C is 86 knots, Vfe per flight
manu=
al. Typical takeoff starts at -1, going to 0 as you get aileron

authority,
=
then +1 as you approach takeoff and throughout the tow. That's

always
worke=
d for me. Takeoff and tow at+2 always required too much forward

stick for
m=
e. YMMV. I think you'll enjoy the V2C. Great xc ship!

Thanks that helps.


  #49  
Old August 22nd 18, 02:22 PM posted to rec.aviation.soaring
FranCP
external usenet poster
 
Posts: 5
Default Stall spin during aero tow? Std cirrus

El domingo, 5 de agosto de 2018, 22:49:48 (UTC-4), escribió:
Have there been stall spins during an aero tow?

Today, I had a very scary aero retrieve. From being towed to fast to-to slow. Anyways the scaries part was when, the tow plane started to climb and to slow. The indicated speed on the glider was 50 knots and decreasing. The glider kept slowing down and sinking under the tow plane into the wake. By this time the glider felt extremely sloopy and it felt like it was ready to drop into stall. Fortunately as I felt the wing wanting to drop, the tug leveld some and got back to a decent speed.

Yes I did radio the pilot askig for 20 indicated more. And I was attempting to release when I hit the wake, but the release on the standard cirrus is far, and my extention had moved from my legs.


I did several hours in my club's std cirry, and lot's of scarry tows on heavy turbulence... It was a Grob std cirrus, all flying tailplane, no winglets and CG hook. It was tail heavy due to a tail boom repair. Not the best combination at all, and get's worse if you have a tow at 2pm midsummer 35°C here in the Andes.

Remember that the glider stabilizes at different attitudes during tow because of the traction of the rope, so probably stall speed is different (maybe higher?) than in free flight. In this glider was obvious that the eccentricity of the CG hook affected heavily. The glider started to felt "uncomfortable" at 90 km/h, like trying to drop a wing.
Also, during aerotow in turbulence we experienced horizontal tail stalls if the towplane went below 100 km/h... full forward stick while the glider still pitching up and a buzz on the stick, reeaaally scary the first times. It recovered control if you centered a little the stick, which in this glider = lowering tail's AoA. Then we got used to go softer on the movements, even if you didn't follow the plane exactly, so no heavy changes on the tail's AoA are induced.
Of course, the glider flew much better when we started to add nose ballast to get the CG out of the back-limit region (it always flew in between the correct limits although).

Anyways, it was by far my favorite so far, a real joy to fly in the ridge. Still has a huge place in my heart.

By the other hand, i had a very similar event to yours, but in a Libelle (H301, flapped)...
Changed the tow plane that day from a 150 supercub to a Stearman, everything’s cool up to there. We were leaving the airstrip during takeoff at about 150~200 ft, and a little uncomfortably slow when suddenly i saw (and i swear it was scarry) the towplane's tail moving up and the plane abruptly changing it's attitude and climbing... first, there was no way to follow the plane in climbing, then i got into the massive rotor of the biplane and dropped a wing. Full opposite rudder and then dropped the other wing, again full rudder when the plane stabilized at a safer speed.
2 remarks:
- Towplane pilot had few hours on the plane and saw the speed way up while leaving the runway, so immediately tried to slow down. Then checked instruments and the plane marked higher IAS.
- when you get checked on a plane like a Stearman, you also need to get a master on radio com decoding... full throttle on that engine plus the wind hitting on your head & headphones, then its real challenging to understand radio talks. So, communication during aerotow is an issue. How can you tell the tow pilot to speed up, without having the risk of him understanding the opposite?

Francisco
  #50  
Old August 23rd 18, 07:35 PM posted to rec.aviation.soaring
[email protected]
external usenet poster
 
Posts: 2
Default Stall spin during aero tow? Std cirrus

I fly unflapped standard ships.
I used to fly a DG300 mainly dry. Tow in 110km/h range is not a problem.
This year I switch to a Discus 2. It has a big AoA also when on the ground and
it need about 130km/h dry to have and more speed when it is wet.

Both ship dry has the same weight and the almost the same surface. I think the main factor is the AoA. The differences are in the AoA and also in the tow hook position (baricentral for DG300 and on the nose for Discus 2) who main influence the stability on tow. When on tow we fly at relative low speed at high AoA fly in an uncommon attitude for the glider.

I always say my load and the desired speed at tow pilot befor take off.
ciao,
giovanni


 




Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Stall/spin and ground reference maneuvers Bill D Soaring 55 March 11th 14 04:35 PM
Improved shear/stall-spin alarms KiloKilo[_2_] Soaring 23 June 11th 13 11:55 PM
Another stall spin Jp Stewart Soaring 153 September 14th 12 07:25 PM
Stall/ Spin testing the RV-12 cavelamb himself[_4_] Home Built 3 May 14th 08 07:01 PM
Glider Stall Spin Video on YouTube ContestID67 Soaring 13 July 5th 07 08:56 AM


All times are GMT +1. The time now is 07:04 PM.


Powered by vBulletin® Version 3.6.4
Copyright ©2000 - 2018, Jelsoft Enterprises Ltd.
Copyright 2004-2018 AviationBanter.
The comments are property of their posters.