One of the things I had long forgotten was that at ignition, the engine slides about 3/8" forward into the tube while firing. This would make any external wring fall free. Another thing I remember is bending the hook inward so the engine casing wedged in the down position.

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Carl McLawhorn
NAR#4717 L2
semroc.com

I built a Scout clone last summer, using Semroc parts ordered individually from their site, and supplemented with materials that I already had on hand. Instead of gauze, I used cloth coated with 30 minute epoxy instead of white glue. Very strong fin joints, but I wouldn't necessarily go with cloth reinforcements if I build another one - they made the joints very thick, and I had to do a fair amount of sanding to level and smooth them out. I would probably still use the cloth to reinforce the motor hook, though. The epoxy worked great; it was quite sandable even though I hadn't added any filler to it.

I used a length of steel music wire for the motor hook. I bent it to the exact shape shown in the supplement to the posted plans. With the cloth and epoxy reinforcement, it is solidly anchored to the tube, and has very little flex.

I also covered the bottom face of the nose cone with a little bit of epoxy after I glued it into the BT in order to help it resist damage from the motor's ejection charge. I used a conventional handheld paper punch to make the three vent holes. Afterwards, I wicked some thin CA around the edges of the vent holes to strengthen them.

My one launch of the Scout so far was with an A8-5. Despite somewhat windy conditions, it shot straight up to about 500-600 ft. Although the ejection charge was quite loud, it didn't do any damage to the model. And that hook held the motor!, resulting in a textbook tumble recovery! Because the motor jumps up into the body tube at ignition with this design, it did get some charring on the inside edges of all three fins, extending halfway down each fin. My model was unpainted, but the fins had been filled and sanded smooth. If you build a Scout, I would suggest painting the fins with a high temp paint.

Using a no-flex music wire motor hook worked better at retaining the motor than anything else that I've tried so far in similarly designed rockets, and I might try using an adapted version of it instead of a normal motor hook in my next Astron Sprite project. It does take good pliers and some patience to make a hook that matches Pete Alway's diagram, but the result is worth it, and I would recommend using that diagram as your guide for making the motor hook.

Mark K.

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SAM # 0011

I haven't flown mine that way. Instead, I always made sure there was just enough stiction to keep the motor all the way forward while on the pad. My rationale was that this added friction would also tend to scrub off momentum as the motor slid aft at ejection thereby reducing the chances of slipping the hook (or worse). Of course, in the case of shotgun ejection charges, the freer the better (edit: so as to let the pressure subside faster).

Maybe I'll have to build another one and try it your way

FWIW, I have a Scout III I need to build, too (one of these days).

Doug

Don't use a twist tie. The Scout has a thin copper wire that holds the engine in place, after the engine is thustered backwards from the ejection charge and is captured by the hook, it changes the center of gravity and the Scout tumbles down, if for some reason the twist tie gets caught up, it won't work.

I will be making an announcement in a day or two about the availability of Scouts and it will be posted under the Rocket Doctyor thread.
This will be an exciting announcement and I am working on it right now, can't reveal it until a day or so, so,, please be watching for this historic announcement.
Thanks

Oh, I think that I must have totally misunderstood Don's post - I thought that he was talking about attaching a circular bail made of thin wire part way down the motor hook. When the motor moved aft at ejection time, it would slip through the circular bail or bracket on its way to the "hook" part of the engine hook. After it was stopped by the hook, the bail would keep the motor from being flipped out and away from the rocket. After reading your response, I realized that I had read the first post all wrong. Late nights combined with early mornings (i.e., burning the candle at both ends) will do that to you.

Mark

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SAM # 0011

No, that's what I meant. But it sounds like the motor moves forward to a point that the wire wouldn't be holding the motor against the hook.

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Don
NAR 53455
"Carpe Diem"

I threw that out on mine. I futzed around with it and decided it was gonna be suspect. I also read they break off fairly easily. So that's why I simply make sure, using a bit of tape, that there's enough friction to hold the motor in place (but only a minimal amount).

Doug

I planned something like that, too. http://home.flash.net/~samily/SSS/Scout-Hook.pdf

There was some egg on my face when I realized the motor slides all the way in

Doug


.

If anyone wants some of this wire (the correct diameter too), let me know. I have a fairly large reel that I bought about 10 years ago that only has about 2" used. I'd be quite willing to "share the joy"

I'm surprisingly (to me) compromising on rocketry. For example, I can forego lots of the "authentic" aspects of cloning, knowing that nobody can tell from the spectator line that the nosecone is plastic underneath the paint, but like Kurt, I have a bunch of stuff around the house where I just had to have some exact thing with the result that I still have all but 2" of it 10 years later.

I wonder if there's a 12-step program for folks like us....

Doug