Towplane performance

Bruce Hoult wrote:
That seems silly.

Sure, taking some random aircraft and using it to tow a glider would be
a silly idea, but surely it's ok to design and build your own
experimental aircraft for the specific purpose of towing gliders!

If this was the only silly FAA rule, perhaps it would be worth worrying
about.

I seem to recall an experimental aircraft called "White Knight"
air-dropping a glider called "SpaceShipOne", with the FAA administrator
present.

Ah, but that did not fit the definition of a "glider tow". In fact, it
does not fit definition of any form of glider launch currently
recognized by the FAA (i.e., aero tow, ground launch, or self-launch),
so the pilots weren't required to have a launch type endorsement...

Marc

The Zenair CH601XL SLSA has an O-200.
With 800# empty weight,
one pilot and light fuel, I wonder what it would tow...

At 300# under max gross, it may just get over the trees
towing 800# or less. 2 people in a 1000#+ aircraft,
hmmm...pretty doubtful there.

I have yet to believe an RV-9 under 1000# empty can
be built with any engine bigger than a O-200. An
inquiry to Van's confirmed that there are no plans
to try to make any of the existing RV kits into SLSA
or ELSA eligible aircraft. They are sturdy and capable,
but a few hundred pounds past the 600kg limit. Flaps,
engine weight, engine accessories, battery, and sturdy
landing gear all add up.

I think a good SLSA towplane would need to be made
from the
bottom up as a single seater. I don't see enough demand
for a single-seat SLSA to make this likely. I'm not
sure we will ever see a single seat SLSA airplane at
all...

At 01:00 07 April 2005, Bill Daniels wrote:

'Roy' wrote in message
. com...
Many thanks for all the advice and suggestions so
far.

Non of the suggestions were for other than standard
(old) aircraft
products.

It has been suggested that an RV9 with a big motor
(160-200hp) would
be great to do the job.

Anyone else considered this approach?
We are not a commercial operation and dont have to
pay our pilots.
There is no insurance problem so this solution has
some appeal. ie
new airframe, easy repair & maintenance.

'Experimental - Amateur Built' aircraft will always
have a 'No glider
towing' paragraph in their operation limitations letter.
However, Sport
Light Aircraft under the new regs seem to have a loophole
that allows glider
towing for profit.

Actually the key design parameter isn't the engine
it's the propeller and
after that, the wing. If you start with a prop optimized
for max thrust at
towing speed and then a wing optimized for that speed,
the HP requirements
go way down. This assumes that the prop RPM can be
reduced by belts or
gearing.

Maybe somebody should cook up an SLA design optimized
for towing. This
would be a very efficient and very quiet airplane.

Bill Daniels


Mark J. Boyd

Getting back to the original thread - what you need
my friend is a Turbo-Czmelak like they used at WGC2003.
1000ft/min+ with a fully loaded Nimbus4/4D/ASH25, throttled
back I believe!

Have you considered winch launching?

Mike Schumann

"Roy" wrote in message
om...
Our operation has started the hunt for a new towplane.
The main criteria is that from our 2200ft strip at sea level we need
to have a two seater (janus) "over the fence" at 300ft in still air.

What would you recommend?
Dont dwell on purchase cost but rather performance/running costs

We would consider
a) Used
b) New
c) Experimental/anything else.

Thanks for your thorts.

Scott wrote in message ...
Uh, but I think you might be missing an important point. Experimental
aircraft such as the RV series can't be used for hire. If the plane and
pilot are provided free, and not compensated in any way, then it might
be doable. I guess you'd have to find a pilot that is only interested
in building time and not wanting to make money...I'm out


Scott

Scott

Presume you haven't heard of that phenomina called Gliding Clubs,
where volunteers act as instructors and others as towpilots... FOR
FREE.

I hear there are lots of them functioning around the world.:-))

AND gentlemen, wonder of wonders, there are other juristictions than
the USA that have glider towing.....sometimes it appears that people
presume only US residents read or contribute to this news group :-)))

Well off to go flying on a great Noo Zeeland day. Yep its FRiday and
the therms are popping.

Roy wrote:

Presume you haven't heard of that phenomina called Gliding Clubs,
where volunteers act as instructors and others as towpilots... FOR
FREE.

I hear there are lots of them functioning around the world.:-))

AND gentlemen, wonder of wonders, there are other juristictions than
the USA that have glider towing.....sometimes it appears that people
presume only US residents read or contribute to this news group :-)))

Well off to go flying on a great Noo Zeeland day. Yep its FRiday and
the therms are popping.

Oh relax Roy. We'll get over ourselves as soon as we're done selling
ourselves to the Chinese. Sometime around the second week of December.
How were those upside down thermals?

Shawn