Releasable tow hooks?

[Curare]

Can anyone tell me the benefits of having a releasable tow hook?

I'm at the point where I should be thinking about this for my sagitta.

I just want to know if it's worth fitting or it was just an 80's gimmick

[OVSS Boss]

You mean 70's gimmick. Great idea, especially in the days when hand brakes wer allowed and you could run downwind and turn around ago again. It is just one more thing to go wrong and real pain to adjust, just get an adjustable hook from Barry Kennedy, way better way to go.

Marc

[Curare]

Righto.

I was actually going to steal Jack's idea from his yardbird, and fit that into the bottom

I went and bought a nice hardened Kavan Towhook yesterday so that'll go in instead.

[ChuckA]

I used a releasable towhook for over 25 years and found them to be very reliable if properly setup. A capture releasable tow hook is essential for getting maximum launch altitude with large floaters such as the Sailaire. Zooming is an exersize in futality with that big high drag wing and maximum altitude can be achieved by towing as slow as possible to reel in as little towline as possible so a capture tow hook is necessary to avoid popoffs. I used a Rocket City Protow hook with all my Sailaires until last year. I replaced the Protow with a conventinal tow hook before last years nats to avoid having to use the special adaptor and paid the price with lower launches.

[TLyttle]

One can get big altitude gains if a releasable towhook is used right: lots of speed, lots of elevator to load the wings, pop the towhook, goes up like a rocket. It ain't easy, and timing is everything; not a great manoever for a lightly-built or draggy model.

[IBWALT]

I have a friend that has one on his sailaire. Like ChuckA says, you need an adapter to make the releasable tow hook work with the larger rings that you find on most winches now days. He is continually looking for an adapter because he leaves them here and there and when he puts the adapter on most guys ask, what's this small ring for?

If your worried about popping off you can always get a file and make a small notch in the tow hook. The notch won't let you run out more winch line to gain more altitude but it will help by preventing the ring from slipping off of the hook prematurely.

Walt

[lincoln]

You can also use a releasable tow hook to save your thin high start after it breaks when flying on a windy day. Dragging the high start back makes fro short duration, though.

I suspect a releasable tow hook that didn't need an adapter would be pretty easy to make. How about, once you have the hook location figured out, adding a vertical pin that comes down a little bit behind the front of the tow hook to trap the ring? A servo could operate it.

[cosmicpossum]

I have several releasables that use the standard ring. I also have a bunch of the Rocket City ones that use the adapter. Both work equally as well as the other.

[quigley257]

I've got one (I believe it's a Rocket City) that I will never use. I can post a pic, or PM me if someone would like to buy it.

--quigley :D

[histarter]

I used a releasable towhook for over 25 years and found them to be very reliable if properly setup. A capture releasable tow hook is essential for getting maximum launch altitude with large floaters such as the Sailaire. Zooming is an exersize in futality with that big high drag wing and maximum altitude can be achieved by towing as slow as possible to reel in as little towline as possible so a capture tow hook is necessary to avoid popoffs. I used a Rocket City Protow hook with all my Sailaires until last year. I replaced the Protow with a conventinal tow hook before last years nats to avoid having to use the special adaptor and paid the price with lower launches.
This reinforces my argument of selectivity generated by the modern high-tension launch system. Being able to kite zoom a large thermal machine via captive hook is rejected, the same as a small thermal machine that doesn’t have the lift quantum to handle the massivity! So only one design will be filtered out!

[tonyestep]

I used to have several of the old Airtronics nylon hooks, but somewhere over the years I lost them. Back in the days when the FAI task was flown with hi-start launches, they were essential; if there was some breeze, you could stretch the rubber way out and ping off really high. Nowadays, the F3B guys do the same thing with fixed hooks, substituting flying skill for the hook mechanism with the dangerous-looking circle-tow. The releasable hooks are not as good as fixed hooks for winch launches. A properly shaped fixed hook will let you kite or circle tow as much as you want, either with twine or mono, so the releasable kind is basically a hi-start only gadget. Also, since it can't be moved back and forth, you can't optimize your launch setup.

[histarter]

I used to have several of the old Airtronics nylon hooks, but somewhere over the years I lost them. Back in the days when the FAI task was flown with hi-start launches, they were essential; if there was some breeze, you could stretch the rubber way out and ping off really high. Nowadays, the F3B guys do the same thing with fixed hooks, substituting flying skill for the hook mechanism with the dangerous-looking circle-tow. The releasable hooks are not as good as fixed hooks for winch launches. A properly shaped fixed hook will let you kite or circle tow as much as you want, either with twine or mono, so the releasable kind is basically a hi-start only gadget. Also, since it can't be moved back and forth, you can't optimize your launch setup.
Tony, you use the ingenuity of throwing money at a problem while letting someone else solve your soaring engineering. Then you have the skill to circle tow with an open hook; and scoff at those of us that cannot duplicate your feat, and require a tool to do so. :o

Tony, who was the one that popped off trying to do a HAM task with Ryan? Obviously your violation of rules negated the fact that the Pike Perfect lost to the Paragon, that your righteous blindness will not accept! :rolleyes:

PS Why would one move the hook back and forth when config and CG are the prime ingredients for hook location that has a bit of tolerance because of RC. Oh I forgot that one must bow to the extreme launch (dark) force and mystically charm it with perfection! :D

[rrdiaz30]

This thread got me looking at stuff that I had stashed away in my "old RC stuff box" that I forgot I had or even used for that matter. Has anyone seen the Graupner 1041 hook before?

Rick

[jtlsf5]

This thread got me looking at stuff that I had stashed away in my "old RC stuff box" that I forgot I had or even used for that matter. Has anyone seen the Graupner 1041 hook before?

Rick

Yes, similar concept and timeframe to the Foremost(?) and Rocket City releasable towhooks.

JT

[Thermaler]

I have used a Fourmost Captive Towhook on my Super Esprit since crash number two. It has been used with every winch or histart that I have been allowed to use.
It has saved many a rekits when I was foolish enough to try and fly the 173" V tail with the Falcon 880 setup loaded in my Vision Tx. The only channel that works the same is the one on the towhook.
It has been the difference between the histart dragging the Super to destruction and a ten minute fix of my nerves. It is very hard to hit the switch, turn off the Tx and let the Super settle into a long glide across the sod farm. I like Fail Safe also!!!
I now fly the woody V tails (4) on one Vision Tx and the woody T tails (8) on another Vision Tx. The full house ships are on the Stylus and the Visions live on.
I have a spare Vision if anybody is interested.
Joe

[schrederman]

I have a couple of EK releasables, and a couple of Foremost, too. I believe I'll use one of the Foremost ones in my Legionair 132 just for grins. I don't know, though, with cf spars and such, it might not take the line tension the rest of the airframe is being modified to take... so, maybe not...

Jack

[tonyestep]

The plastic ones might (or might not) take it, Jack, but it seems like one could make up an aluminum one that would be strong enough -- if you really wanted a releasable hook. I have made some adjustable hooks and although I haven't tried it, I'd think it wouldn't be too hard to make the releasable kind.

[VH-ASC]

Can anyone tell me the benefits of having a releasable tow hook?

I'm at the point where I should be thinking about this for my sagitta.

I just want to know if it's worth fitting or it was just an 80's gimmick

Have Airtronics hook in my Sagitta 900. I never have any pop offs. Never had any release issues either. If I could find another on I'd use it again. Don't really think it is/was a gimmick. If the simpler fixed hook works for you then use it, but don't trash those who use the releasable hook and can make it work.

Jeremy

[Curare]

Whoa, wait a second, put the flamethrower down Jeremy, I was asking the question as to whether their worth it, I wasn't trashing the idea.

Oh, and histarter, I'd appreciate it if you didn't turn MY thread into another battlefield for HAM.

[tonyestep]

For more hashing back and forth on the merits and demerits of releasable hooks, and some pictures of a couple of golden oldies, here's an old RCG thread:
http://www.rcgroups.com/forums/showthread.php?t=263872

[VH-ASC]

Whoa, wait a second, put the flamethrower down Jeremy, I was asking the question as to whether their worth it, I wasn't trashing the idea.

Oh, and histarter, I'd appreciate it if you didn't turn MY thread into another battlefield for HAM.

Ok, flamethrower away. Sorry, the trashing comment was not ment to be directed at you.

Just tired of the trashin and bashing for using "old tech" stuff. I was a contest yesterday and you sould have heard the comments about that releasable tow hook; "bad idea", "it will jam", "are you sure that will work?", and the best was the blank stare when someone asked what tht extra servo was for. Never mine that the glider was built in 1987 and that was he norm then.

Jeremy

[ChuckA]

I have a couple of EK releasables, and a couple of Foremost, too. I believe I'll use one of the Foremost ones in my Legionair 132 just for grins. I don't know, though, with cf spars and such, it might not take the line tension the rest of the airframe is being modified to take... so, maybe not...

Jack

I used EK releasable tow hooks for all my standard class sailplanes but wouldn't trust them for anything bigger. I converted them to a capture tow hook by installing a pin to prevent the tow ring from sliding off before release. I also connected the tow hook to the servo with a rigid link that required me to unlock the tow hook with the radio to hook up the tow ring, and then latch the tow hook with the radio. Never launched with the radio off as long as I used the EK tow hook. I always used the Rocket City Protow for my larger sailplanes.

[histarter]

I used EK releasable tow hooks for all my standard class sailplanes but wouldn't trust them for anything bigger. I converted them to a capture tow hook by installing a pin to prevent the tow ring from sliding off before release. I also connected the tow hook to the servo with a rigid link that required me to unlock the tow hook with the radio to hook up the tow ring, and then latch the tow hook with the radio. Never launched with the radio off as long as I used the EK tow hook. I always used the Rocket City Protow for my larger sailplanes.
Yes, I followed the same format. I did recieve the last shipment of EK hooks with the captive screw modification from Bob Elliot, and probably have a few of them left.
Kite zooming with them is neat. The wind would lock a normal hook onto a histart requiring the dive and weak zoom, whereas releasing the hook simply yielded an efficient zoom to the sailplane's nominal airspeed. Ergo when outlawing them wouldn't work experts merely increased tension to make them fail! [This is just humorous conjecture! (that I am forced to define so as not to harass the lesser experts)] :D :D