To Pawnee or not to Pawnee...that is the question...

On Oct 22, 9:27 am, Dan G wrote:
In fact we even tried towing with a Rotax Falke -
only 100hp or so, but very efficient.

"As a tug, the SF25C Rotax Falke seems to perform very well, climbing
with heavy two-seaters at 400ft/min. This is marginally slower than,
say, a Robin DR400, but this Falke uses only half as much fuel and the
noise pollution is much less. In Germany, official analysis of
comparative tug noise estimates a single tow in a Robin DR400 type tug
equates to 4.8 tows in a SF25C Rotax Falke. Glider-tug speed
compatibility, similar wing loadings and aspect ratios, and reduced
wake turbulence, mean the motorglider aerotowing option offers
significant safety features.

The manufacturer's fuel consumption figures are 16-18 litres (c 3.5
gallons) an hour, hardly thirsty for tugs. Taking into account all the
costs of operating the Falke, including an engine rebuild every 2,000
hours, insurance, fuel and maintenance costs, a Falke is estimated by
its makers to tow at about 60 per cent of the cost of today's
conventional tugs."

http://www.fffoundation.co.uk/SGart.html

On Oct 22, 5:07 am, Dan G wrote:
In fact we even tried towing with a Rotax Falke -
only 100hp or so, but very efficient.

"As a tug, the SF25C Rotax Falke seems to perform very well, climbing
with heavy two-seaters at 400ft/min. This is marginally slower than,

Well, imagine that. If the students (and/or instructors...and/or
private ship owners) really **** of the tow pilot, he can shut the
"money making motor" off and soar for himself! I like that idea.

Having been stuck as the only "tow slave" on many booming days when I
wanted to soar (but was too chicken to shut off the motor in the
Pawnee or CallAir). Yeah, I know pilots that have taken Pawnee
"gliders" to 20,000+ feet in wave -- I guess I never got THAT
desperate.

-Pete

On Oct 22, 6:07 am, Dan G wrote:
On Oct 22, 9:27 am, Dan G wrote:

In fact we even tried towing with a Rotax Falke -
only 100hp or so, but very efficient.

"As a tug, the SF25C Rotax Falke seems to perform very well, climbing
with heavy two-seaters at 400ft/min. This is marginally slower than,
say, a Robin DR400, but this Falke uses only half as much fuel and the
noise pollution is much less. In Germany, official analysis of
comparative tug noise estimates a single tow in a Robin DR400 type tug
equates to 4.8 tows in a SF25C Rotax Falke. Glider-tug speed
compatibility, similar wing loadings and aspect ratios, and reduced
wake turbulence, mean the motorglider aerotowing option offers
significant safety features.

The manufacturer's fuel consumption figures are 16-18 litres (c 3.5
gallons) an hour, hardly thirsty for tugs. Taking into account all the
costs of operating the Falke, including an engine rebuild every 2,000
hours, insurance, fuel and maintenance costs, a Falke is estimated by
its makers to tow at about 60 per cent of the cost of today's
conventional tugs."

http://www.fffoundation.co.uk/SGart.html

That article was published in 2000. How many are currently in use as
tugs?

Ours was used for a couple of comps in 2005 with great effect (matched
the Pawnees as due the very quick descent and only used 1/3 the fuel),
but since then it hasn't been insured for towing. Another club is a
using a G109 with the turbo Rotax, but has performance issues once the
5-minute boost period is over (i.e., if you want to go higher than
about 3,000'). Finally I know of a Rotax-engined microlight being used
for towing in South Africa.

So, being honest, it's not being used widely (at least not to my
knowledge). There's no good reason though - maybe it's a combination
of it not being around for long, that there's still a lot of Pawnees
and Robins knocking around which are still in use, and that new things
rarely get taken up widely in gliding even if they're proven (e.g.
plasma rope).


Dan

A couple of links about towing with Rotax power. First the microlight
in SA:

http://www.glidingmagazine.com/FeatureArticle.asp?id=91

And also on using Rotax Falkes:

http://www.glidingmagazine.com/Featu...cle.asp?id=117

I bet a fair few Falkes are being used as tugs in Germany - any of our
members from over there know?


Dan

I bet a fair few Falkes are being used as tugs in Germany - any of our
members from over there know?

Bleurgh, it would help if I RTFA I linked to. At least 20 are used for
towing over there, and that was in 2001. A good point made in the
article is also that, of course, a motorglider tug still gets used for
circuit training, field landing exercises etc., and all that ups
utilisation and lowers costs. And it is damned quiet - ours is *much*
quieter than our Pawnee.


Dan

Dan G wrote:
I bet a fair few Falkes are being used as tugs in Germany - any of our
members from over there know?

Bleurgh, it would help if I RTFA I linked to. At least 20 are used for
towing over there, and that was in 2001. A good point made in the
article is also that, of course, a motorglider tug still gets used for
circuit training, field landing exercises etc., and all that ups
utilisation and lowers costs. And it is damned quiet - ours is *much*
quieter than our Pawnee.

I think you'll also find that a number of German operations are using
modern glass ultralights as tugs. IIRC the Wasserkuppe uses a Virus or
similar - a nose gear gear high-wing anyway - for towing single seaters
and a GR400 for their ASK-21s.


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

About as many as Scheibe elected to build...

Scheibe has recently gone through ownership change, and hopefully will get more
focussed on building gliders.

Frank Whiteley wrote:
On Oct 22, 6:07 am, Dan G wrote:
On Oct 22, 9:27 am, Dan G wrote:

In fact we even tried towing with a Rotax Falke -
only 100hp or so, but very efficient.
"As a tug, the SF25C Rotax Falke seems to perform very well, climbing
with heavy two-seaters at 400ft/min. This is marginally slower than,
say, a Robin DR400, but this Falke uses only half as much fuel and the
noise pollution is much less. In Germany, official analysis of
comparative tug noise estimates a single tow in a Robin DR400 type tug
equates to 4.8 tows in a SF25C Rotax Falke. Glider-tug speed
compatibility, similar wing loadings and aspect ratios, and reduced
wake turbulence, mean the motorglider aerotowing option offers
significant safety features.

The manufacturer's fuel consumption figures are 16-18 litres (c 3.5
gallons) an hour, hardly thirsty for tugs. Taking into account all the
costs of operating the Falke, including an engine rebuild every 2,000
hours, insurance, fuel and maintenance costs, a Falke is estimated by
its makers to tow at about 60 per cent of the cost of today's
conventional tugs."

http://www.fffoundation.co.uk/SGart.html

That article was published in 2000. How many are currently in use as
tugs?