Making Engine Clips?

Making Engine Clips?

Post by Robert W. Blas » Thu, 19 Dec 1996 04:00:00



I'd like to avoid dealing with Estes as much as possible.  The only thing
I haven't been able to find in the mail order companies (i.e.
Mountainside, Magnum, Discount Rocketry, Commonwealth) is Engine Clips.

So I'm wondering -- what do all you other scratchbuilders do?  (I'd rather
not use the friction fit method.)

Here's my question...
Has anyone made Engine Clips?  How'd you do it?

Thanks!
-Robert

 
 
 

Making Engine Clips?

Post by Vince Huege » Thu, 19 Dec 1996 04:00:00


In article


Quote:

>I'd like to avoid dealing with Estes as much as possible.  The only thing
>I haven't been able to find in the mail order companies (i.e.
>Mountainside, Magnum, Discount Rocketry, Commonwealth) is Engine Clips.

>So I'm wondering -- what do all you other scratchbuilders do?  (I'd rather
>not use the friction fit method.)

>Here's my question...
>Has anyone made Engine Clips?  How'd you do it?

>Thanks!
>-Robert

A medium gauge 'music' wire can be cut to length and bent on the ends with
pliers to form a hook. It should be available in hobby or craft stores. Take
care as you glue it on the engine tube to be sure the tab points over the edge
to the center, since the round wire will slip.
The flat metal hooks are much easier. Quest has hooks too, 6/$1.

 
 
 

Making Engine Clips?

Post by Stefan Wimme » Thu, 19 Dec 1996 04:00:00


Quote:

> So I'm wondering -- what do all you other scratchbuilders do?
> Has anyone made Engine Clips?  How'd you do it?

Hobby or craft stores should be able to sell you some flat metal to bend
your own hooks. Steel wires (music or piano wire) can be used too.

Quote:
> I'd rather not use the friction fit method.

Why not? If done properly (not just with 98mm motors) it works.

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Making Engine Clips?

Post by Robert W. Blas » Thu, 19 Dec 1996 04:00:00


Quote:

> > So I'm wondering -- what do all you other scratchbuilders do?
> > Has anyone made Engine Clips?  How'd you do it?

> Hobby or craft stores should be able to sell you some flat metal to bend
> your own hooks. Steel wires (music or piano wire) can be used too.

Thanks. How is it sold? What section/category is it sold under?

Quote:
> > I'd rather not use the friction fit method.

> Why not? If done properly (not just with 98mm motors) it works.

I don't like friction fit because I feel like it is weakening the model
and messing up the ends by repeatedly jamming taped motors into it.  But
then who knows, I might be doing it wrong.

thanks!
-Robert

 
 
 

Making Engine Clips?

Post by Mike Vande Bu » Thu, 19 Dec 1996 04:00:00



: >
: > So I'm wondering -- what do all you other scratchbuilders do?
: > Has anyone made Engine Clips?  How'd you do it?

Amazingly enough, Estes still sells engine clips separately.  (Well, OK,
it's an assortment: 1 mini, 3 regular, 2 large.)

--

 
 
 

Making Engine Clips?

Post by The Silent Observe » Thu, 19 Dec 1996 04:00:00


Quote:

> I'd like to avoid dealing with Estes as much as possible.  The only thing
> I haven't been able to find in the mail order companies (i.e.
> Mountainside, Magnum, Discount Rocketry, Commonwealth) is Engine Clips.

> So I'm wondering -- what do all you other scratchbuilders do?  (I'd rather
> not use the friction fit method.)

> Here's my question...
> Has anyone made Engine Clips?  How'd you do it?

Get two pairs of sturdy needle nose pliers, and a few lengths of .064" to
..096" (1/16" to 3/32") diameter music wire, and bend them yourself.  The
only critical dimension is the 70mm spacing between the forward thrust
bearing end and the rear hook end.  If you find the clip you've made is a
little too flexible (entirely possible -- I'm guessing on the right wire
diameters; I can tell you 1/32" aka .032" is much too small) you can use
two, on opposite sides of the motor mount.

The real beauty of this method, BTW, is that you can make these to any
length you like.  Want to use mini-motors?  Bend the clip with a 55mm
free length.  Want to use Apogee 10.5mm motors?  Bend the clip to fit the
longest motor, and use a spacer in the mount (a 10.5 mm tube coupler
works well) for the shorter ones.  Want to use the overlength AT 18mm and
24mm motors?  Get the casing dimensions (don't worry about ejection wells
or nozzle extensions for this) and bend the clip to fit.

Added advantage: you can very the depth of the spring clip end to keep it
clear of the jet blast, and you can tailor the profile for the best motor
retention (i.e., you can include a little "hook" in the latch surface to
bind over the rear edge of the casing in some motor designs).

Bending wire precisely is an art, and requires practice -- but the raw
materials are cheap, and the tools are very durable.  Beware, however of
trying to cut thick music wire with standard wire cutters; the wire is
hard enough to notch the jaws!  Best to use a cutoff wheel in a Dremel
for anything over 1/16" diameter.

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Making Engine Clips?

Post by Karl von Jen » Thu, 19 Dec 1996 04:00:00


In article


Quote:
>I'd like to avoid dealing with Estes as much as possible.  The only thing
>I haven't been able to find in the mail order companies (i.e.
>Mountainside, Magnum, Discount Rocketry, Commonwealth) is Engine Clips.

>So I'm wondering -- what do all you other scratchbuilders do?  (I'd rather
>not use the friction fit method.)

I found myself in a sticky situation a few months back. Night before a
launch and my rocket doesn't have an engine clip. Bummer. So I made one
from a coat hanger. Not exactly a high-tech material, but it works. Free
too!

I took a length of coat hanger wire, bent one end over and poked it
through the motor mount tube to act as a motor block. The other end I
bent over doubled, so that the sharp point of the cut wire holds the
motor securely against the motor block. It worked very well and the coat
hanger wire stays flexible enough that removing and inserting engines is
a breeze.

Just make sure that the hot exhaust isn't blasting directly on the wire.
That kind of heat will melt an engine clip, piano wire, or coat hangers.

Karl

 
 
 

Making Engine Clips?

Post by Stefan Wimme » Fri, 20 Dec 1996 04:00:00


Quote:

> SW> Hobby or craft stores should be able to sell you some flat metal to bend
> SW> your own hooks. Steel wires (music or piano wire) can be used too.

> Thanks. How is it sold? What section/category is it sold under?

Here in Germany I find it where the model airplane stuff is located. The
broader variants of the flat steel bars is often used for connections of the
wings to the fuselage. I don't know what they use the narrower ones, but
they're there.

Quote:
> I don't like friction fit because I feel like it is weakening the model
> and messing up the ends by repeatedly jamming taped motors into it.  But
> then who knows, I might be doing it wrong.

Well, on smaller motors (up to 29mm) I'm using the thrust ring method. The
tape around the forward end of the motor is there to seal against the ejection
gases and to provide centering. It should not force you to force the motor in
the rocket. The thrust is mediated by the thrust ring and the short impulse of
the ejection wil be hold by the tape between body tube and thrust ring (you
should use good tape here!). I never had a failure in many flight with this
scheme. OTOH, I had some motor hooks fail because of the punctual stress of
materials.

Good luck.
--
 ____________________________________________________________________
|                                               __                   |
|        Stefan Wimmer                        _|__|                  |
|        Hardware Designer          cellware |_|__                   |
|                                              |__| broadband        |

| Tel    (+49 30) 46 70 82 35                Gustav-Meyer-Allee 25   |
| Fax    (+49 30) 46 30 76 58                13355 Berlin            |
| WWW    http://www.cellware.de/                Germany              |
|____________________________________________________________________|
Do 't tou h the f op ydi ks su f ce!  (Anonymous)
It's the government. It doesn't have to make sense.  (B. Kaplow)

 
 
 

Making Engine Clips?

Post by Roger Iv » Fri, 20 Dec 1996 04:00:00



Quote:

>> Here's my question...
>> Has anyone made Engine Clips?  How'd you do it?

> Get two pairs of sturdy needle nose pliers, and a few lengths of .064" to
> ..096" (1/16" to 3/32") diameter music wire, and bend them yourself.  

Personally, I mutilate paper clips (man's most useful invention since the
wire coat hanger).
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Making Engine Clips?

Post by Bob Kapl » Sat, 21 Dec 1996 04:00:00



Quote:

> I'd like to avoid dealing with Estes as much as possible.  The only thing
> I haven't been able to find in the mail order companies (i.e.
> Mountainside, Magnum, Discount Rocketry, Commonwealth) is Engine Clips.

Launch Pad. Chuck makes his own. At NARAM this year I had a long talk with him
regarding what he used and how he did it. The material is a 12' roll of spring
steel that cost about $5. The method was a pain. To form them you have to heat,
bend, and anneal. 50% of them end up trash. It didn't sound worth my time.

I bot a bunch from him.

Quote:
> So I'm wondering -- what do all you other scratchbuilders do?  (I'd rather
> not use the friction fit method.)

> Here's my question...
> Has anyone made Engine Clips?  How'd you do it?

I've made my own, out of assorted sizes of mucic wire. I also use the brass
strip material to make my "Kaplow Klips". Both work OK.

        Bob Kaplow      NAR # 18L       TRA # "Abort, Retry, Fail?"