using winch instead of aerotow

Our club has gradually moved to winch over the last few years and now we use
ordinary aerotow rope on the winch (its cheap,made everywhere ,easy to
splice
and wears extremely well)Rope bungees slightly so pilots have to be trained
how to keep an even load on the cable (makes you a smoother pilot as well)
Average launch heights off 3300ft runway 1400-1600ft, record is a single
astir to 2700ft
We do tickets for launching at $8 each, 1 ticket for winch launch, 1 ticket
per 500ft
aerotow launch normally to 2000ft
We have noticed these effects

1: more flying in marginal conditions (its cheap )
2:more students because its cheap
3:A MASSIVE INCREASE IN CLUB PROFIT per launch (5 TIMES AS MUCH) on far
less turnover. The winch now makes multiple times what aerotowing
used to make for FAR LESS CAPITAL COST.
We have priced the winch to have costs of less than a quarter of the ticket
price
4:Pilots are better at getting away from lower heights
T
he difference is such that plans are being mooted to build a second winch
and look at a bullwheel arrangement and endless cable on a small diesel to
haul the cables
out while a launch is going on

We have a hundred members at our club and have noticed an increase in flying
activity per member as a result of winching (again cost per launch)

We appreciate the feedback. Your launch heights of 50%+ of the length of
towline laid out wins the prize so far. I wonder if your extraordinary
success has anything to do with the synthetic rope you're using. You
didn't say the typical wind strength you launch into and your airport
elevation, both of which can make some difference.

Most everybody else is reporting only 25-35%. If your numbers can be
verified, I believe you guys are really on to something. Could you
describe the rope a bit further, size, construction, etc?

Thanks again,

Bob Johnson

goneill wrote:

Our club has gradually moved to winch over the last few years and now we use
ordinary aerotow rope on the winch (its cheap,made everywhere ,easy to
splice
and wears extremely well)Rope bungees slightly so pilots have to be trained
how to keep an even load on the cable (makes you a smoother pilot as well)
Average launch heights off 3300ft runway 1400-1600ft, record is a single
astir to 2700ft
We do tickets for launching at $8 each, 1 ticket for winch launch, 1 ticket
per 500ft
aerotow launch normally to 2000ft
We have noticed these effects

1: more flying in marginal conditions (its cheap )
2:more students because its cheap
3:A MASSIVE INCREASE IN CLUB PROFIT per launch (5 TIMES AS MUCH) on far
less turnover. The winch now makes multiple times what aerotowing
used to make for FAR LESS CAPITAL COST.
We have priced the winch to have costs of less than a quarter of the ticket
price
4:Pilots are better at getting away from lower heights
T
he difference is such that plans are being mooted to build a second winch
and look at a bullwheel arrangement and endless cable on a small diesel to
haul the cables
out while a launch is going on

We have a hundred members at our club and have noticed an increase in flying
activity per member as a result of winching (again cost per launch)

The rope is extremly light in comparison to any type of metal cable which
helps for height and secondly we tried the
plasma types which are so light that the drag/bow you get in the line is
magnifying at the upper elavations of the launch and premature backreleases
were occurring.
The biggest difference is to that with the bungee effect of the rope we are
getting a very rapid accelleration to the speed required for full climb and
the normal rotation to full climb is taking place at a level that would
normally give someone who is not used to the dynamics of this type of cable
,frankly if would frighten you.
The fact is with extensive testing from the whole instructors panel it was
found that AS LONG AS you have the speed, the rotation at that that point is
only "unloading the cable stress" and if a weak link or cable break was
going to happen it would happen while in your very short initial climb.The
second part of this is if you DON'T go into full climb to maintain an even
tension on the cable it will bungee and you will get the slow
/fast/slow/fast type of launch.
The testing has shown that as long as you have the speed a cable break or
power loss is not a problem even at 100 ft
We have a large club fleet ,Pukateks,grob103,grob 102s ,pw5s,plus and large
private owner fleet and through all these types the dynamics are the same
,the primary factor is the speed and maintaining even load by rotating

A senior pilot/instructor from another club recently came here and spent the
whole day winching with our instructors
with the idea of converting to this rope as they have an identical field
length and were, as most operations are, just getting a third of length in
height.

The wind speed and direction at our field is generally crossed, seldom
straight down the runway at 0-20 knots range
Our winch is a large v8 petrol motor driving through an automatic gearbox to
an old truckaxle with the drums mounted where the wheels were ,I believe the
drum hubs had to be reinforced as the rope being wound on at speed was
compressing the hub and distorting it badly,

"Bob Johnson" wrote in message
...

We appreciate the feedback. Your launch heights of 50%+ of the length of
towline laid out wins the prize so far. I wonder if your extraordinary
success has anything to do with the synthetic rope you're using. You
didn't say the typical wind strength you launch into and your airport
elevation, both of which can make some difference.

Most everybody else is reporting only 25-35%. If your numbers can be
verified, I believe you guys are really on to something. Could you
describe the rope a bit further, size, construction, etc?

Thanks again,

Bob Johnson

goneill wrote:

Our club has gradually moved to winch over the last few years and now we
use
ordinary aerotow rope on the winch (its cheap,made everywhere ,easy to
splice
and wears extremely well)Rope bungees slightly so pilots have to be
trained
how to keep an even load on the cable (makes you a smoother pilot as
well)
Average launch heights off 3300ft runway 1400-1600ft, record is a
single
astir to 2700ft
We do tickets for launching at $8 each, 1 ticket for winch launch, 1
ticket
per 500ft
aerotow launch normally to 2000ft
We have noticed these effects

1: more flying in marginal conditions (its cheap )
2:more students because its cheap
3:A MASSIVE INCREASE IN CLUB PROFIT per launch (5 TIMES AS MUCH) on far
less turnover. The winch now makes multiple times what aerotowing
used to make for FAR LESS CAPITAL COST.
We have priced the winch to have costs of less than a quarter of the
ticket
price
4:Pilots are better at getting away from lower heights
T
he difference is such that plans are being mooted to build a second
winch
and look at a bullwheel arrangement and endless cable on a small diesel
to
haul the cables
out while a launch is going on

We have a hundred members at our club and have noticed an increase in
flying
activity per member as a result of winching (again cost per launch)

On Fri, 15 Aug 2003 19:37:14 GMT, Bob Johnson
wrote:


We appreciate the feedback. Your launch heights of 50%+ of the length of
towline laid out wins the prize so far. I wonder if your extraordinary
success has anything to do with the synthetic rope you're using. You
didn't say the typical wind strength you launch into and your airport
elevation, both of which can make some difference.

Most everybody else is reporting only 25-35%. If your numbers can be
verified, I believe you guys are really on to something. Could you
describe the rope a bit further, size, construction, etc?

The other club on my home airfield is also experimenting with PU cable
(Dyneema) since 18 months now. They have modified one drum of their
double-drum winch (afaik 280 hp), so there is a very direct comparison
between steel and Dyneema cable.

Overall the performance advantage of Dyneema is not overwhelming - on
a 3.400 ft runway the maximum height advantage is only 150 ft with a
light Ka-8 and subjectively less with an ASK-21 or DG-505. We are
pretty sure that the winch launch of the steel cable is already pretty
much perfectionized on this particular winch, which does explain the
little benefit of Dyneema.

On the other side, handling of the rope is vastly improved.

see http://www.aec-landau.de/


Bye
Andreas