Tow plane types/mods for high density altitude glider towing

On Friday, August 23, 2019 at 9:30:29 AM UTC-7, son_of_flubber wrote:
On Thursday, August 22, 2019 at 11:50:40 AM UTC-4, 2G wrote:

I only consume 1/2 gallon to launch my ASH31Mi motorglider to 3kft (the same was true for the 26e and DG400, and most every other self-launcher that I can think of, well maybe not the Space Shuttle). So, for a 4 hour flight my "burn rate" is 1 pint per hour.

Self-launch gliders are obviously appealing, but I'm curious about their limitations wrt density altitude and turbulence.

What is your climb rate in your typical density altitude?

Do you ever launch in turbulent conditions with lots of sink?

What density altitude leads you to cancel your flight?

What is the highest density altitude that you have launched in?

My ASH26Mi climbs at about 450 ft/m at 9000 ft density altitude. A little better than a Pawnee towing me. At sea level it is close to 900 ft/min. I routinely launch at 9000 density (typical for a noon launch at Truckee) and have done as high as 9999 (that's the limit of the electronic sign at the end of Runway 20).

ASH26Mi. “But there is no such thing� :-)

On Monday, August 26, 2019 at 12:36:49 PM UTC-7, Darryl Ramm wrote:
ASH26Mi. “But there is no such thing� :-)

There is ONE such thing. Would have been two if I hadn't run out of money.
Jim

John’s ASH26Mi is a thing of beauty. Having asked Schleicher about a 26E to Mi conversion a long time ago I was blown away by the amount of work this took.

Best tow plane ( well helicopter) was a Hughes 500 D at the Warbirds airshow in NZ and the opening of the world gliding champs.
Take-off roll was about 60m and it went up at 1600ft per min.
The trick at the top was slowing the helicopter down till the glider stalled and hung on the belly hook.
Need to get the videos of this uploaded sometime. Make for great viewing

Ah but can you hand hold a tow rope behind a 500D? :-)

On Monday, August 26, 2019 at 1:53:15 PM UTC-7, Ross wrote:
Best tow plane ( well helicopter) was a Hughes 500 D at the Warbirds airshow in NZ and the opening of the world gliding champs.
Take-off roll was about 60m and it went up at 1600ft per min.
The trick at the top was slowing the helicopter down till the glider stalled and hung on the belly hook.
Need to get the videos of this uploaded sometime. Make for great viewing

1600 ft/m bet the helicopter pilot could have pulled more torque. The 500 I was flying would do 2200 fpm with a load all day

On Monday, August 26, 2019 at 1:53:15 PM UTC-7, Ross wrote:
Best tow plane ( well helicopter) was a Hughes 500 D at the Warbirds airshow in NZ and the opening of the world gliding champs.
Take-off roll was about 60m and it went up at 1600ft per min.
The trick at the top was slowing the helicopter down till the glider stalled and hung on the belly hook.
Need to get the videos of this uploaded sometime. Make for great viewing

I believe it was also used for at least one outlanding from a very small flat area in a river bed. The chopper didn't need a ground roll, and the glider didn't need much of one.

On Monday, August 26, 2019 at 10:17:29 AM UTC-7, jfitch wrote:
On Friday, August 23, 2019 at 9:30:29 AM UTC-7, son_of_flubber wrote:
On Thursday, August 22, 2019 at 11:50:40 AM UTC-4, 2G wrote:

I only consume 1/2 gallon to launch my ASH31Mi motorglider to 3kft (the same was true for the 26e and DG400, and most every other self-launcher that I can think of, well maybe not the Space Shuttle). So, for a 4 hour flight my "burn rate" is 1 pint per hour.

Self-launch gliders are obviously appealing, but I'm curious about their limitations wrt density altitude and turbulence.

What is your climb rate in your typical density altitude?

Do you ever launch in turbulent conditions with lots of sink?

What density altitude leads you to cancel your flight?

What is the highest density altitude that you have launched in?

My ASH26Mi climbs at about 450 ft/m at 9000 ft density altitude. A little better than a Pawnee towing me. At sea level it is close to 900 ft/min. I routinely launch at 9000 density (typical for a noon launch at Truckee) and have done as high as 9999 (that's the limit of the electronic sign at the end of Runway 20).

Sounds good: do you post your flights on OLC? My numbers are based on actual flights that you can view on OLC. I really wish my climbs were that good, but they aren't, and that is flying with 21m tips.

Tom

On Monday, August 26, 2019 at 7:24:32 PM UTC-7, 2G wrote:
On Monday, August 26, 2019 at 10:17:29 AM UTC-7, jfitch wrote:
On Friday, August 23, 2019 at 9:30:29 AM UTC-7, son_of_flubber wrote:
On Thursday, August 22, 2019 at 11:50:40 AM UTC-4, 2G wrote:

I only consume 1/2 gallon to launch my ASH31Mi motorglider to 3kft (the same was true for the 26e and DG400, and most every other self-launcher that I can think of, well maybe not the Space Shuttle). So, for a 4 hour flight my "burn rate" is 1 pint per hour.

Self-launch gliders are obviously appealing, but I'm curious about their limitations wrt density altitude and turbulence.

What is your climb rate in your typical density altitude?

Do you ever launch in turbulent conditions with lots of sink?

What density altitude leads you to cancel your flight?

What is the highest density altitude that you have launched in?

My ASH26Mi climbs at about 450 ft/m at 9000 ft density altitude. A little better than a Pawnee towing me. At sea level it is close to 900 ft/min. I routinely launch at 9000 density (typical for a noon launch at Truckee) and have done as high as 9999 (that's the limit of the electronic sign at the end of Runway 20).

Sounds good: do you post your flights on OLC? My numbers are based on actual flights that you can view on OLC. I really wish my climbs were that good, but they aren't, and that is flying with 21m tips.

Tom

Numbers are based on IGC log files over 3 seasons. I've written a program that analyzes the log files for climb rate. I don't bother much with OLC. Looking at 31 climbs in the same conditions and on the same day only. a few minutes before or after me, I seem to climb somewhat better (that is a 31-18). The 26Mi is a bit lighter maybe.