Low Tow Uses
Mike Chreptak
I'm an Instructor with the Royal Canadian Air Cadets Gliding Program. I
was going through our gliding manual, trying to refresh my memory for
the spring season. A question has come up that I'm wondering if someone
here can help me answer. The question is this: What advantages are there
to low tow? Our training manual doesn't go into detail about it, except
mentioning that it is used for descents and long distance tows. It's
been a long time since I've done any tows in the low tow position
myself, so I can't remember how it makes station keeping any easier,
which is the only reason given for using it on long distance tows.
Any insights are greatly appreciated,
Mike
(Take out the "Z" to respond using e-mail)
Richard Friday
In Australia low tows are the recommended method. My club routinely perform
dual tows however, so I get to practice both fairly frequently. The low tow
is much easier, particularly for a low time student. A simple analogy I use
is that of a pea in a spoon - low tow - which tends to want to self centre.
Balance a pea on top of the spoon - high tow - and you have to work at it.
I think the reason that the GFA recommend low tow is because it reduces the
risk of tug upset. You can get dramatically out of station in low tow and
still see the tug, but you don't have to go too far above the tug in high
tow and you lose him altogether. If this happens too close to the ground
you can pull his tail up to the point where he loses elevator (back stick)
authority and the whole combination is at risk.
RF
Birger.W...@dnv.com
For clubs doing both winching and aerotow, low tow should be an added
safety feature in order to remind the glider pilot what he's doing at
the moment. If aerotowing is most common or only way of towing, I
don't think it matters much.
Birger
MikeYankee
miles. In such cases it is also customary to use a double rope. The added
length really makes the flying easier.
A few operations use low tow for normal operations for "safety" reasons. Low
tow reduces the chance of a glider kiting up and raising the towplane's tail,
forcing it into the ground. This has happened with the standard tow position,
but never with proper training and technique.
Just my opinion.
Dan Cromer
During climb, the high tow position keeps the glider above the propwash
but level with the towplane, giving good visibility of other aircraft
for both tow (in mirror) and glider pilot. However, careful technique
must be used to avoid towplane upset by glider kiting up, pulling
towplane tail up. Generally, the station-keeping is also easier as the
towplane wings (or wheels, etc.) may be on or slightly above the horizon
to the glider pilot -- of course when the terrain is relatively flat.
Low tow during climb makes the glider hidden to the tow pilot in many
towplanes, but does have the advantage of being harder to kite up for
towplane upset. High tow is the preferred method where I fly in Florida
as Civil Air Patrol cadet orientation pilot.
During level or descending flight, low tow position may be preferred as
propwash then is directly behind or above towplane path, low tow
position just below propwash isn't as far below towplane altitude as
during climb.
Dan
Walter Kahn
eight and three quarter hours on tow that day! (read the funny story of
that trip and others in my book 'A glider pilot bold..')
My main concern was a possible rope break while over the English Channel
but apart from that there were no problems. I spent time in low tow but
did not find it any advantage over our normal high tow.
Having carried out over 11,000 tows as the tug pilot, I am only too
aware of the very occasional too high glider, am always ready for this,
but I firmly believe that it is better to see the glider behind you in
high tow.
Good luck with your training. Wally Kahn (I fly at Lasham, England).
In article <3AC462C4...@Zmail.com>, Mike Chreptak
<mikech...@Zmail.com> writes
--
Walter Kahn
Caracole
>Mike Chreptak wrote in message
Low tow is typically preferential on long xc tows because it puts the
glider below rather than in the tow planes prop wash and it also gives
the glider pilot a little better view of the tow plane.
There are a few countries that use low tow as a preferred position for
normal aero tow. They do this to help prevent tug upsets.
In the U.S., normal tow position is level with the tow plane. This puts
the glider in the middle of the normal cone of movement. As an
instructor and tow pilot this means that when towing through rotor the
pilot has a little more time in all directions before he starts to get into
trouble. If he starts out already in low tow, he has little flexibility to
get lower during turbulence. He is also in a position where if the rope
breaks anywhere other than at the nose of the glider. He has a high
probability of getting it over his glider.
M Eiler
Deputy Dog
One other item no one has mentioned is the efficiency aspect. When you are
in low tow, you are creating a downward moment on the tail of the tug
aircraft. This allows his elevator to produce less negative lift in order
to maintain his flight attitude, since you are providing some of it for him,
so his aircraft has less induced drag.
Not a big factor, but mayby worth mentioning to students from a theory
standpoint.
I use low tow when doing multiple intro/commercial rides to overcome the
boredom.
-Dave
"Mike Chreptak" <mikech...@Zmail.com> wrote in message
news:3AC462C4...@Zmail.com...
Rainer Horbert
to my knowledge all countries with REAL STRONG THERMALS (eg. in Namibia ;-)
using low tow for
safety reasons. Also the risk for the pilot of the towplane
is greatly reduced on low tow.
Hals- und Beinbruch!
Rainer
Bitterwasser Segelflug
H Nixon
I've done over 9000 tows as pilot or instructor in the glider and about 3500 in front. Visibility is better from the glider and equal in the tug. It is far easier to do and teach.
Nuff said
Unclhank
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Mike Chreptak
Thanks to everyone that have already responded, and any others that may
still respond. All of your answers have helped me understand this a lot
more.
Now I just hope I can teach some of this to my next set of "victims"... :)
Mike C
(Remove the "Z" to use my e-mail address)
Eric Greenwell
rfr...@bigpond.com says...
When do you go to the low tow position? Does the glider remain close
to the ground and let the tow plane climb up to the correct position,
or is the transition made after both aircraft are several hundred feet
off the ground?
We sometimes have wind shear near the ground, were the wind speed
increases quickly in the first 100'. If the tow plane gets above the
glider, it can slow down enough to leave the glider uncomfortably
slow.
--
Remove REMOVE from my e-mail address to reply
Eric Greenwell
Richland, WA (USA)
Bill Daniels
seat. When the Brigliebs used TG-3's as training gliders at the old El
Mirage field, low tow was the only way the instructor could see the tug
reliably
It is also possible that low tow is a little more efficient since the
tailplanes of both the tug and glider are producing a little less down load.
Bill Daniels
"Mike Chreptak" <mikech...@Zmail.com> wrote in message
news:3AC462C4...@Zmail.com...
Jim Kellett
news:3AC462C4...@Zmail.com...
> Hi!
>
> to low tow?
In climbing tow, the propwash is well below the line-of-flight of the
towplane, and the glider is "comfortable" riding above it (the propwash).
In XC tows, the propwash is more directly behind the towplane, requiring a
relatively turbulent ride (if the glider insists on maintaining the same
"sight lines" on thse towplane) or an uncomfortably high tow to stay in calm
air.
In level (cruise, cross country) tows, the low tow position stays below the
propwash, maintains a similar "sight line" on the towplane (only slightly
lower than high tow in climbing flight) and is slightly more efficient by
unloading the towplane's horizontal tail. It also makes the flight much
more relaxing for the glider pilot, since at the phugoid oscillation in ALL
towropes which becomes more pronounced with longer ropes and higher towing
speeds is easier to manage.
Jim Kellett
Chief CFI, Skyline Soaring Club
Virginia, USA
John Firth
out low and slow because the top plane pilot has enthusiastically pulled up
in the low level wind gradient. This situation can be quite dangerous if
a student is in control, but slow to react. I would be very wary about
staying in low tow after take off, though this is of course also the most
critical time for towplane upset.
Stay tight on position when being towed in rough conditions for the first
few hundred feet and do not let the towplane get much above the horizon.
John Firth ( past safety critic for the SAC instructing committee)
Janusz Kesik
plane climb and when I'll enter the propwash I stay in it till release. It
smoothes the thermal inducted turbulence, increases the control's
effectivness (faster airflow around airfoil), helps to keep the rope spanned
and from the low tow position largens the safety margins in case of strong
thermal 'bump'.
The drawback is that when the tug's engine isn't mainained well, then the
oil drops from the exhaust pipes may make Your's glider windshiels a little
dotty.
--
Janusz Kesik
Aero Club of Czestochowa, Poland
jant...@interia.pl
www.soaring.enter.net.pl
>
> When do you go to the low tow position? Does the glider remain close
> to the ground and let the tow plane climb up to the correct position,
> or is the transition made after both aircraft are several hundred feet
> off the ground?
> --
GRETHE R BULUKIN
fed with a teaspoon. Was it that unclear?
Birger W. Bulukin
Rich Carr skrev i meldingen <9a2sel$i19$1...@fcnews.fc.hp.com>...
>Birger.W...@dnv.com wrote:
>: For clubs doing both winching and aerotow, low tow should be an added
>: safety feature in order to remind the glider pilot what he's doing at
>: the moment. If aerotowing is most common or only way of towing, I
>: don't think it matters much.
>
>Yikes, I don't think I want to be looking *up* at the winch!
>
>Or isn't that what you meant...
>
>- Rich Carr
Catherine Conway
A lot of postings have dealt with the aerotow upset scenario. Here is an
article printed here in Oz about 15 years ago
-Cath
http://www.aus.com/Cath/tow-upset1.jpg
http://www.aus.com/Cath/tow-upset2.jpg
http://www.aus.com/Cath/tow-upset3.jpg
http://www.aus.com/Cath/tow-upset4.jpg
Catherine Conway
A lot of postings have dealt with the aerotow upset scenario. Here is an
article printed here in Oz about 15 years ago
-Cath
http://www.aus.com/Cath/tow-upset1.jpg
http://www.aus.com/Cath/tow-upset2.jpg
http://www.aus.com/Cath/tow-upset3.jpg
http://www.aus.com/Cath/tow-upset4.jpg