New M&K impluse hook

[Anonymous]

I had a chance to talk with Andrew tonight. He advised me that impulse tow hooks don’t work well here due to frequently wet grass on our fields in the morning. He said that the grass wets the line and causes it to jerk as it plays out and that increasing the adjustment to prevent premature release can result in no release at launch time. He suggested I change the order to conventional hooks unless M&K has done something recently to remedy this.
What do you think about this. As you know, Andrew is a very competent flyer and is quite familiar with the conditions here. I’m inclined to take his advice. Tom V

[Anonymous]

Tom,

Yes, the first impluse hooks could be “fooled” by the high pulse of the wet line slipping to release the latch. The design now has a safety feature to prevent this. There is a safety latch that prevents the latch weight from moving. When the hook load is high enough to signal the switch which drives the stab servo moves the stab higher and “arms” the safety latch. The signal to the switch starts a count down timer, if the model experiences a large vertical acceleration (ie release) the weight moves and the latch opens, if the no large acceleration happens in this 2 sec window, the servo moves the stab back and re-engaes the safety latch.

This hook is a totally redesigned hook than the first one that Andrew had / has. They have worked this for over 3 years. In the beginning, I was skeptical because we would see them chase models that the line did not release properly. This past MM they had none of this.

I believe this is a sound design. I am getting my first impluse hook in June-July as well.

The two negitives is that for some flyers is this hook / model can not be “dumped” off– ie you’er in good air and just want to pull and release. Those of us that fly a more “aggressive” bunt don’t do this anyway. We must circle, position and launch. The second is that you can pull as hard as you want when towing a impluse hook model an so must remember / adjust when flying a conventional hook.

A good question. I’m including Andrew. I respect his opinon- he has experience with the old hook. I’m not sure if he saw or talk to M&K about the new hook.

Just that you know, I had taken a different approach over the last 3 years and developed a relatching hook– servo on the hook latch– if I wanted to abort a lauch I can. I’ve been thru a similar development and had early success followed by problems that I think I have finally resolved.

This came out of Ken Bauer’s development of the e-hook that Victor Stamov developed- they used strain gages to indicate the load to drive a servo to latch and unlatch. Victor has had a 2-3 year problem in development as well. Ther are others in Europe working similar concepts.

So it gets back to one of my earlier emails. If you want to be in the top 5-10 of the USA, ie the leading edge, then the impluse hook or relatching hook is the next development. If you want to be compeitive at all USA and most international contests, then the conventional hook e-model is great. If you want to go out ocasionally and be competitive, the the mechanical model is good. The one other area I did not mention is if you like gagets- having a nature of first use, then the impluse hook is for you as well.

From a practical side, the standard hook cost is going up and will get higher as more and more go to the impluse. From a sales pitch, M&K say that once a customer gets experience with the the impluse hook, they start converting thier fleet.— JIM

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