Tow plane types/mods for high density altitude glider towing

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?

It's not the same with other self-launchers, of course, but my S10-VT
has a turbocharged, 4-cylinder engine rated at 115 (nominal)
horsepower.Â* With the turbo, it achieves its rated power to a very high
altitude, which I haven't seen stated, but it has a published service
ceiling of 33,000' MSL.Â* Density altitude has no effect on it other than
some reduction in propeller efficiency and engine temperature limits.Â* I
imagine the higher true airspeed for a given IAS at takeoff at high
altitude airports makes up for reductions in wing lift.Â* At maximum
power it burns around 5 gallons/hour (about 3.2 gph in cruise at 18,000'
MSL for repositioning flights), so I'd guess I burn less than a half
gallon of gas per normal soaring flight, including taxi and takeoff.

Engine overhaul will cost a few pennies more than with the smaller ships...

On 8/23/2019 10:30 AM, 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?


--
Dan, 5J

On Friday, August 23, 2019 at 12:30:29 PM UTC-4, 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?

Also...

How long is your runway? Is it level? Is it paved?

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?

At 2000 ft DA it is 500 ft/min; at 9000+ DA it is 300 ft/min. Always seeking lift, so this is mixed.


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

Not with lots of sink - try to launch when there is lift.


What density altitude leads you to cancel your flight?

None.


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

9600 ft.

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? :-)