Towing w LSA (Light Sport Aircraft)

[Jeffrey Banks]

Towing w LSA (FAA defined Light Sport Aircraft)?


Is anyone doing this?

Without a horsepower limit for Light Sport Aircraft it seems that a
small airframe and a big engine might be an ideal towplane.

The GW limit of 1320 lbs (599kg) and max cruise speed of 120knots do
not seem restrictive for such a tug.




Jeff Banks

[Mike Schumann]

Is it legal to tow if you just have a light sport license? If not, what's
the point?

Mike Schumann

"Jeffrey Banks" > wrote in message
...
> Towing w LSA (FAA defined Light Sport Aircraft)?
>
>
> Is anyone doing this?
>
> Without a horsepower limit for Light Sport Aircraft it seems that a
> small airframe and a big engine might be an ideal towplane.
>
> The GW limit of 1320 lbs (599kg) and max cruise speed of 120knots do
> not seem restrictive for such a tug.
>
>
>
>
> Jeff Banks
>
>
>
>

[Bill Daniels]

The point is that an airplane can be designed that is optimized for aero
tow. This theoretical aircraft could deliver far better tow performance on
half the HP of a Pawnee. It could be almost silent while using smaller
quantities of cheaper fuel. I agree that it's possible within the limits of
the Sport Light Aircraft regulations. We'll have to see if someone pick up
the challenge.

It's not the pilot, it's the airplane.

Bill Daniels

"Mike Schumann" > wrote in message
link.net...
> Is it legal to tow if you just have a light sport license? If not, what's
> the point?
>
> Mike Schumann
>
> "Jeffrey Banks" > wrote in message
> ...
> > Towing w LSA (FAA defined Light Sport Aircraft)?
> >
> >
> > Is anyone doing this?
> >
> > Without a horsepower limit for Light Sport Aircraft it seems that a
> > small airframe and a big engine might be an ideal towplane.
> >
> > The GW limit of 1320 lbs (599kg) and max cruise speed of 120knots do
> > not seem restrictive for such a tug.
> >
> >
> >
> >
> > Jeff Banks
> >
> >
> >
> >
>
>

[Tim Ward]

"Mike Schumann" > wrote in message
link.net...
> Is it legal to tow if you just have a light sport license? If not, what's
> the point?
>
> Mike Schumann
>

Private pilots can fly LSAs. Those people who are towing hang gliders are
lobbying for towing with the experimental LSAs (the Dragonflys and so
forth).
If you could build an LSA similar to a Katana with 150 HP or so, I bet
that could make a dandy towplane. LSAs don't have to go through a complete
certification, so it's possible someone could design a towplane that would
have lower fuel burn and faster cycle time than existing towplanes.
It might even be able to double as a motorglider trainer when it wasn't
towing.

Tim Ward

[Jack]

Jeffrey Banks wrote:

> Without a horsepower limit for Light Sport Aircraft it seems that a
> small airframe and a big engine might be an ideal towplane.
>
> The GW limit of 1320 lbs (599kg) and max cruise speed of 120knots do
> not seem restrictive for such a tug.

What do you consider a big engine?

A new, lightened Piper Pawnee (currently mt wt of 1288 lbs) would be
better than yet another high-wing lashup with horrible visibility from
the cockpit.


Jack

[Stefan]

>>> Is anyone doing this?

In Europe, this is becoming more and more common. Towing works
astonishingly well with 100 hp and one of those new planes. The limit is
when the glider is very heavy (fully loaded two seater) or the runway is
very short and soft. Towing with 3 gal/hour and with remarkably little
noise is much cheaper and neighbour-friendlier, even if a tow it last
10% longer.

There are currently two categories of "new tow planes": Motorgliders
(such as the Super Dimona, in the USA called Katana XTreme) and modern
ultalights, as they are called here (see for example http://www.remos.com/).

All in all, in Europe we strongly believe that this is the future of towing.

Stefan

[Martin Gregorie]

On Tue, 13 Sep 2005 09:29:17 +0200, Stefan wrote:

>>>> Is anyone doing this?
>
> In Europe, this is becoming more and more common. Towing works
> astonishingly well with 100 hp and one of those new planes. The limit is
> when the glider is very heavy (fully loaded two seater) or the runway is
> very short and soft. Towing with 3 gal/hour and with remarkably little
> noise is much cheaper and neighbour-friendlier, even if a tow it last 10%
> longer.
>
When I visited the Wasserkuppe in 2003 they were using a Robin GR400 for
their two-seat fleet (ASK-21) and a Pelikan UL for the single seaters.
That's a reasonable tow-plane test: OK, they operate off tarmac, but
launch is usually down-wind and down-hill so the tow plane needs to be
fairly capable.

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

[Bill Daniels]

"Stefan" > wrote in message
...
> >>> Is anyone doing this?
>
> In Europe, this is becoming more and more common. Towing works
> astonishingly well with 100 hp and one of those new planes. The limit is
> when the glider is very heavy (fully loaded two seater) or the runway is
> very short and soft. Towing with 3 gal/hour and with remarkably little
> noise is much cheaper and neighbour-friendlier, even if a tow it last
> 10% longer.
>
> There are currently two categories of "new tow planes": Motorgliders
> (such as the Super Dimona, in the USA called Katana XTreme) and modern
> ultalights, as they are called here (see for example
http://www.remos.com/).
>
> All in all, in Europe we strongly believe that this is the future of
towing.
>
> Stefan

I don't believe an optimum design tow plane would look anything like a
touring motorglider. The key to performance and economy is the propeller.
It should be really big and slow turning. Remember, propeller blades are
just rotating wings. They work best at the L/D max just like a sailplane.
Think of a three to four meter diameter prop turning at 1000 RPM. The
touring motorglider airframes won't accommodate a prop that big.

I'm thinking of something that would look like an oversize ultralight with
the pilot way forward for the best view and a pusher prop over a low wing.
The wing would baffle what little sound the prop made so it should be very
quiet. A very slow prop could be easily driven with a tooth belt. 130 HP
should be more than enough for the heaviest 20 meter two-seater. A water
cooled Honda or Subaru engine might work great.

Bill Daniels

[John Galloway]

The Pik 27 looks as if it is getting close to completion.
It is a small single seat low wing Rotax 914 engined
machine with rear fuselage air brakes that has been
designed specifically as a glider tug and is expected
to outperform a Pawnee for towing and be much more
economical. See:

http://www.windcraft.fi/pik27/welcome

John Galloway


At 13:00 13 September 2005, Bill Daniels wrote:
>
>'Stefan' wrote in message
...
>> >>> Is anyone doing this?
>>
>> In Europe, this is becoming more and more common.
>>Towing works
>> astonishingly well with 100 hp and one of those new
>>planes. The limit is
>> when the glider is very heavy (fully loaded two seater)
>>or the runway is
>> very short and soft. Towing with 3 gal/hour and with
>>remarkably little
>> noise is much cheaper and neighbour-friendlier, even
>>if a tow it last
>> 10% longer.
>>
>> There are currently two categories of 'new tow planes':
>>Motorgliders
>> (such as the Super Dimona, in the USA called Katana
>>XTreme) and modern
>> ultalights, as they are called here (see for example
>http://www.remos.com/).
>>
>> All in all, in Europe we strongly believe that this
>>is the future of
>towing.
>>
>> Stefan
>
>I don't believe an optimum design tow plane would look
>anything like a
>touring motorglider. The key to performance and economy
>is the propeller.
>It should be really big and slow turning. Remember,
>propeller blades are
>just rotating wings. They work best at the L/D max
>just like a sailplane.
>Think of a three to four meter diameter prop turning
>at 1000 RPM. The
>touring motorglider airframes won't accommodate a prop
>that big.
>
>I'm thinking of something that would look like an oversize
>ultralight with
>the pilot way forward for the best view and a pusher
>prop over a low wing.
>The wing would baffle what little sound the prop made
>so it should be very
>quiet. A very slow prop could be easily driven with
>a tooth belt. 130 HP
>should be more than enough for the heaviest 20 meter
>two-seater. A water
>cooled Honda or Subaru engine might work great.
>
>Bill Daniels
>
>

[Fred]

I've long thought an experimental category A/C dedicated only to towing
would be a good alternative to the Pawnee. The correct design would
get better fuel efficiency, be quieter, have longer TBO and probably be
liquid cooled so thermal shock is not such a problem on let down. Two
questions, though: who wants to design a specialized airplane with such
limited market potential, and what would the insurance companies say
about towing with an A/C in the experimental category? Otherwise,
bring it on! Fred

[Tim Ward]

"Bill Daniels" > wrote in message
...
>
> "Stefan" > wrote in message
> ...
> > >>> Is anyone doing this?
> >
> > In Europe, this is becoming more and more common. Towing works
> > astonishingly well with 100 hp and one of those new planes. The limit is
> > when the glider is very heavy (fully loaded two seater) or the runway is
> > very short and soft. Towing with 3 gal/hour and with remarkably little
> > noise is much cheaper and neighbour-friendlier, even if a tow it last
> > 10% longer.
> >
> > There are currently two categories of "new tow planes": Motorgliders
> > (such as the Super Dimona, in the USA called Katana XTreme) and modern
> > ultalights, as they are called here (see for example
> http://www.remos.com/).
> >
> > All in all, in Europe we strongly believe that this is the future of
> towing.
> >
> > Stefan
>
> I don't believe an optimum design tow plane would look anything like a
> touring motorglider. The key to performance and economy is the propeller.
> It should be really big and slow turning. Remember, propeller blades are
> just rotating wings. They work best at the L/D max just like a sailplane.
> Think of a three to four meter diameter prop turning at 1000 RPM. The
> touring motorglider airframes won't accommodate a prop that big.
>
> I'm thinking of something that would look like an oversize ultralight with
> the pilot way forward for the best view and a pusher prop over a low wing.
> The wing would baffle what little sound the prop made so it should be very
> quiet. A very slow prop could be easily driven with a tooth belt. 130 HP
> should be more than enough for the heaviest 20 meter two-seater. A water
> cooled Honda or Subaru engine might work great.
>
> Bill Daniels
>

You may be right, from an aerodynamic point of view, but if it can work as a
motorglider/trainer too, then a club or FBO can use it more, and that helps
with the amortization/justification for buying it.

I think a towplane-only airplane would be a fairly low-wing loading canard,
towing from somewhere near the CG. Then tug upsets would become extremely
rare. Another weirdness of design would be to drive two overlapping props
(slightly offset fore and aft). The disc loading of each prop would be low,
like a big slow turning prop, but the gear legs wouldn't be so long. They'd
give up some efficiency to the overlap, of course.

But I don't think the market is big enough to support a dedicated tug
design. Compromising in the direction of a motor glider usable for training
or rides lets an operator get more use out of his investment.

Tim Ward

[Jeffrey Banks]

John,

This PIK 27 design looks like a very good candidate for the US LSA
category.

I like the liquid cooled engine and the dive brakes on the empennage.


Jeff

[bumper]

Having owned an aircraft with a Rotax 914 (turbocharged & intercooled),
Except for the liquid cooled heads, I wouldn't thing this engine is all that
well suited for a tow plane. Not that it isn't a good engine, it's just that
it seems to require more maintenance than the less sophisticated Lycoming or
Continental. Check the Rotax SB's and AD's to see what I mean:

http://www.rotax-owner.com/

For a motor glider like the Stemme, which spends much of it's time soaring
and puts little time on the engine, this isn't so much an issue. And the
reliable starting and smooth running of the 4-stroke Rotax is a real plus.
But for a hard working tug, the maintenance demands may be less inviting.

The 912 / 914 will burn 100 LL, but they don't like it as much as premium
mogas. 100LL use can result in early overhaul due to clogged oil passageways
and sticking rings and valves.

The new diesel engines might be better suited for tug duty?

bumper
"Jeffrey Banks" > wrote in message
...
> John,
>
> This PIK 27 design looks like a very good candidate for the US LSA
> category.
>
> I like the liquid cooled engine and the dive brakes on the empennage.
>
>
> Jeff
>
>
>
>