On Wednesday, October 4, 2017 at 10:20:21 PM UTC-5, wrote:
UN came with a Zuni or HP type hook installed by Applebay under a 337, that for those who aren’t familiar, kind of looked like a small Schweizer hook that retracts flush with the skin. The first time I attempted aerotowing with it, we tried twice to connect it with the line guy and it released and retracted when the towplane added power. The previous owner later said, yeah that happens sometimes, think the cable needs adjusted. I’ve also heard of Zuni accidents related to a possible premature release for what it’s worth. I taped over it and used the Tost CG hook without looking back. I figure Klaus knew what he was doing more or less.

Mike

For what it is worth, Mike, I believe there has been one (not plural) Zuni accident attributed to pre-mature release that was likely related to the release itself. That one was missing a key component that, if not installed, assured that the release could operate on its own, with no pilot action required. I have now heard of two others that have behaved similarly (yours and one other). I have multiple hundreds of launches with my Zuni and have NEVER experienced a release that I did not initiate. Mine has all its parts, and is of a slightly different design that does not rely on a hidden spring that, if it is not there, you won't know it is not there and the release will malfuntion.

I am not sure when the design changed, but if all the parts are there and properly functioning, the release performs as designed and intended.

As for the "benefit" of a nose hook, well the rubber cover on my BS1 nose hook got torn, and I have not been successful at fab and install of a new cover, so I taped it over. Howled like a giant coke bottle. I now only use the CG hook, and have had no problems.

As someone else said, "It will cost a lot, and the benefit will be small". But sometimes for your own piece of mind, and benefit to others down the road, we just bite the bullet, spend the money and do something.

Steve Leonard
Zuni 2 Serial 28
Between 300 and 400 launches on my Applebay hook.