Pull plane by tail hook

I just rechecked the regs. Tow rope weak link can not be stronger
than twice the weight of the sailplane. Sailplanes sometimes exceed 1000
pound gross weight.

The weak link must not be less than 85 percent of the gross weight
of the sailplane.

Using this range, 850 to 2000 pounds on the tail of a towplane is not
out of reason. Another place in the installation design of tail
hooks calls for loads to stay within 30 degrees of backwards, as I
recall. I would try to keep the load as straight aft as possible.

In article . net,
(d b) wrote:

Checkout the numbers on towing gliders.

The number is based on the gross weight of the glider multiplied by
a fudge factor. There is a lot of stored energy when you pull with this
much force, be aware of breaking a springy rope. Might be good to
put a weak link on the plane end so that a weak link break will take
the rope away from the plane.

As I recall, a 1000 lb breaking strength isn't out of reason at all.

The towplane scenario pretty closely simulates the load direction
when pulling the plane backward into a hanger.



In article iKBZb.371333$na.564927@attbi_s04, (Ben Jackson)
wrote:
In article ,
Tarif Halabi wrote:

Is it ok to pull my Piper Archer by the tail hook back into the hanger?
Does any one know if that will cause any damage?

If your Archer is like my Comanche the tail ring is where you attach a
big honking (300lb?) weight while you're jacking up the wings. It must
be stronger than it looks! I've been considering doing the same thing
as you.

On Sat, 21 Feb 2004 14:06:51 GMT, (d b) wrote:

Using this range, 850 to 2000 pounds on the tail of a towplane is not
out of reason. Another place in the installation design of tail
hooks calls for loads to stay within 30 degrees of backwards, as I
recall. I would try to keep the load as straight aft as possible.

That's the other factor of course. I've only seen tailhook installation on
taildraggers, but I doubt that, on trigear airplanes, they merely unscrew
the tiedown ring and screw in the hook release mechanism. There's probably
reinforcement that's added as well, which would make moot any comparison to
pulling the plane by the stock tiedown ring.

On taildraggers, the line releases are generally attached to the tailwheel
spring...which, of course, already has a heavy-duty attachment.
Homebuilders and antique owners use the same devices to secure planes
during handpropping. See:

http://www.bowersflybaby.com/tech/tailhook.html

Ron Wanttaja

Ron Wanttaja wrote:

: That's the other factor of course. I've only seen tailhook installation on
: taildraggers, but I doubt that, on trigear airplanes, they merely unscrew
: the tiedown ring and screw in the hook release mechanism. There's probably
: reinforcement that's added as well, which would make moot any comparison to
: pulling the plane by the stock tiedown ring.

FWIW, the banner tower based at my field uses a Cessna Hawk XP. The banner
tow point is the tail tiedown. I asked if there are any reinforcements
added, and he said "No.".

--
Aaron Coolidge (N9376J)

Towhook is available as standard equipment on all C182's. No reinforcements
added. THE 182 has been towing for more than 40 years now. The hook
bolts in place of the tiedown ring. It will tow a considerable amount of
weight, to understate things a bit. It's bad form to break the rope on tow,
but it can happen.


In article ,
wrote:
On Sat, 21 Feb 2004 14:06:51 GMT, (d b) wrote:

Using this range, 850 to 2000 pounds on the tail of a towplane is not
out of reason. Another place in the installation design of tail
hooks calls for loads to stay within 30 degrees of backwards, as I
recall. I would try to keep the load as straight aft as possible.

That's the other factor of course. I've only seen tailhook installation on
taildraggers, but I doubt that, on trigear airplanes, they merely unscrew
the tiedown ring and screw in the hook release mechanism. There's probably
reinforcement that's added as well, which would make moot any comparison to
pulling the plane by the stock tiedown ring.

On taildraggers, the line releases are generally attached to the tailwheel
spring...which, of course, already has a heavy-duty attachment.
Homebuilders and antique owners use the same devices to secure planes
during handpropping. See:

http://www.bowersflybaby.com/tech/tailhook.html

Ron Wanttaja

I used the tail tie down loop thingie to winch a Piper Saratoga for years.
No problems. As someone else mentioned, the jacking procedure is to put a
weight on that loop to hold it down, then use two jacks under the wings to
lift all three wheels off the ground. So that loop is pretty dang stout. I
wouldn't use it to pull tree stumps, but winching from it is fine.

"Tarif Halabi" wrote in message
om...
Hi,

Is it ok to pull my Piper Archer by the tail hook back into the hanger?
Does any one know if that will cause any damage?

Regards
Tarif Halabi
C-GQGD

I think the geneal concensus is that if the pull is moderate and reasonbly
straight back, you should be fine. Obviously the eyelet has to be strong
enough to handle being used as a tie down.

Of course, the rub is defining what is moderate and reasonably straight
back. Some judgment required there. I'd play it safe - if you really need
to winch on it, then rig some way to pull by the gear.

- Mark

(Tarif Halabi) wrote in
om:

Is it ok to pull my Piper Archer by the tail hook back into the
hanger? Does any one know if that will cause any damage?

Piper says no. [Big surprise.] I know some folks who do it with no
apparent trouble.

When I needed to do something similar to my turbo Arrow (similar, but
somewhat heavier aircraft) I looked at the tail ring and decided there
just wasn't all that much strength in what it was tied into.

The Piper official recommendation (they even have a drawing somewhere)
shows using two leather straps, one around each main. [Remember, this
is an Arrow.] I wasn't very found of that either.

What I finally rigged was a pull cable out to a roller. Through the
roller I threaded another nylon cable to hooks. [Think of a big "Y",
where the top of the Y goes to the aircraft, and the bottom goes to the
winch.] The hooks simply clipped into the underwing tiedown rings,
which (I feel) are tied into a much stronger structure.

Another advantage - the whole thing tends to be somewhat self centering.
But I also added a remote control to the electric winch, so I could
stand in front of the plane with the toebar for steering. Worked really
neat for the year or so that I needed it.



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TriSoft ph 512-385-0316
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