Towplane performance

"Roy" wrote in message
om...
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.

Have a look at this site.
http://www.soarmn.com/soaring_files/...ison_table.jpg
This Towplane table was done in 1994. The calculation are all referenced to
see level and standard temperature. The performances appear high,
but are not, because most of the comments on this group referred to High
temperature and high altitude. All Climb performances are with a fully
loaded
twin Grob. Acceleration on the Ground was not taken into account.
For example if the temperature is 80F and a 1000ft the factor becomes .77
Please note how well the Zenith 300 with a 180 HP does.

I could well imagine Dick VanGrunsven RV 9 with a 180HP would do very well
but
the RV 10 would be a better choice, as the airframe is stronger and designed
to take a bigger engine, the airframe would still be well under 1500lb if it
is a
very basic tow plane. For example the RV 9 with a pilot and fuel and a max
160HP
( allowed only) has a power loading of 10.

The RV10 with the same pilot and fuel would, but 180 HP, would have the
same
power loading as the RV9. The RV 10 has a larger wing area, it would climb
better
at the speeds we tow at. Also the Airframe is designed for up to 260HP.

For a club with a small membership and limited options I would favour a
stripped down
C-170 or 172 with 180HP if Summer temperature and see elevation allow.
Parts and services are readily available and the performance is not bad at
all for 180HP.
Regards
Udo

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


Udo Rumpf wrote:

"Roy" wrote in message
om...

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.


Have a look at this site.
http://www.soarmn.com/soaring_files/...ison_table.jpg
This Towplane table was done in 1994. The calculation are all referenced to
see level and standard temperature. The performances appear high,
but are not, because most of the comments on this group referred to High
temperature and high altitude. All Climb performances are with a fully
loaded
twin Grob. Acceleration on the Ground was not taken into account.
For example if the temperature is 80F and a 1000ft the factor becomes .77
Please note how well the Zenith 300 with a 180 HP does.

I could well imagine Dick VanGrunsven RV 9 with a 180HP would do very
well but
the RV 10 would be a better choice, as the airframe is stronger and
designed
to take a bigger engine, the airframe would still be well under 1500lb
if it is a
very basic tow plane. For example the RV 9 with a pilot and fuel and a
max 160HP
( allowed only) has a power loading of 10.

The RV10 with the same pilot and fuel would, but 180 HP, would have
the same
power loading as the RV9. The RV 10 has a larger wing area, it would
climb better
at the speeds we tow at. Also the Airframe is designed for up to 260HP.

For a club with a small membership and limited options I would favour a
stripped down
C-170 or 172 with 180HP if Summer temperature and see elevation allow.
Parts and services are readily available and the performance is not bad
at all for 180HP.
Regards
Udo

"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
I did not make a point about the viability as it relates to
the regulation, but rather performance.
Udo




Udo Rumpf wrote:

"Roy" wrote in message
om...

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.


Have a look at this site.
http://www.soarmn.com/soaring_files/...ison_table.jpg
This Towplane table was done in 1994. The calculation are all referenced
to
see level and standard temperature. The performances appear high,
but are not, because most of the comments on this group referred to High
temperature and high altitude. All Climb performances are with a fully
loaded
twin Grob. Acceleration on the Ground was not taken into account.
For example if the temperature is 80F and a 1000ft the factor becomes
.77
Please note how well the Zenith 300 with a 180 HP does.

I could well imagine Dick VanGrunsven RV 9 with a 180HP would do very
well but
the RV 10 would be a better choice, as the airframe is stronger and
designed
to take a bigger engine, the airframe would still be well under 1500lb if
it is a
very basic tow plane. For example the RV 9 with a pilot and fuel and a
max 160HP
( allowed only) has a power loading of 10.

The RV10 with the same pilot and fuel would, but 180 HP, would have the
same
power loading as the RV9. The RV 10 has a larger wing area, it would
climb better
at the speeds we tow at. Also the Airframe is designed for up to 260HP.

For a club with a small membership and limited options I would favour a
stripped down
C-170 or 172 with 180HP if Summer temperature and see elevation allow.
Parts and services are readily available and the performance is not bad
at all for 180HP.
Regards
Udo

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:
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.

If you are in the US, towing gliders with experimental aircraft is
prohibited by the FAA. I can't remember the exact place where it is
spelled out (it's probably in an AC), I'm sure someone else will know...

In article ,
Marc Ramsey wrote:

If you are in the US, towing gliders with experimental aircraft is
prohibited by the FAA.

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!

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

--
Bruce | 41.1670S | \ spoken | -+-
Hoult | 174.8263E | /\ here. | ----------O----------

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

"Roy" wrote in message
om...
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

It certainly looks like it could do the job....however
not sure which club wants to own the first $500k+ towplane




At 14:00 03 April 2005, Bruce Hoult wrote:
In article ,
Stefan wrote:

Chris Rollings wrote:

I can't think of any regularly used towplane that
will
achieve what you want.

A Pilatus PC6 will do this just nicely. Ok, agreed,
not exactly a
'regularly used towplane'.

Don't forget the NZ turbine cropduster offshoot being
sold for
skydiving, the PAC 750XL:

http://www.utilityaircraft.com/

Brake release to 12,000 ft takes 12 minutes with a
2 tonne load. The
plane without the skydivers (but with fuel & pilot)
weighs 1400 kg, so
it can presumably climb at over 2000 fpm lightly loaded.

Ground roll at MTOW is 1244 ft, so presumably considerably
less at
light weights.


Biggest problem: best rate of climb is at 95 knots,
best angle is at 85
knots.

--
Bruce | 41.1670S | \ spoken | -+-
Hoult | 174.8263E | /\ here. | ----------O----------

I learned behind a 180 hp Super Cub and remember seeing loaded glider and
tow plane off the ground in 3-500 feet depending on wind. plenty fast climb
too.
we were operating out of the middle of a 3000 ' strip so demos coul depart
and arrive at the same place either direction. I understand that there was
an STC for 200 hp on the sme airframe and the extra 20 hp ought to really do
the job on the Janus. Only problem is that Supr Cubs bring a premium these
days.
Cheers!

"Stewart Kissel" wrote in
message ...
It certainly looks like it could do the job....however
not sure which club wants to own the first $500k+ towplane




At 14:00 03 April 2005, Bruce Hoult wrote:
In article ,
Stefan wrote:

Chris Rollings wrote:

I can't think of any regularly used towplane that
will
achieve what you want.

A Pilatus PC6 will do this just nicely. Ok, agreed,
not exactly a
'regularly used towplane'.

Don't forget the NZ turbine cropduster offshoot being
sold for
skydiving, the PAC 750XL:

http://www.utilityaircraft.com/

Brake release to 12,000 ft takes 12 minutes with a
2 tonne load. The
plane without the skydivers (but with fuel & pilot)
weighs 1400 kg, so
it can presumably climb at over 2000 fpm lightly loaded.

Ground roll at MTOW is 1244 ft, so presumably considerably
less at
light weights.


Biggest problem: best rate of climb is at 95 knots,
best angle is at 85
knots.

--
Bruce | 41.1670S | \ spoken | -+-
Hoult | 174.8263E | /\ here. | ----------O----------