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  #11  
Old 04-04-2020, 08:39 PM
rocket.aero rocket.aero is offline
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Quote:
Originally Posted by sandman
I was looking into a timer but when I shouldn't get the 10.5mm motors I gave up.


Lack of 10.5mm motor availability is a good reason to build the sustainer for a project such as this with a 13mm sustainer. The scale properties would be slightly off, but no one would ever notice unless it was pointed out to them.

Our Internats models were constructed as a 'vertical cluster,' with the igniters for both the booster and the sustainer ignited simultaneously. The igniter for the sustainer lit a short 30mm-long bit of t-fuse that was inserted into the sustainer nozzle, giving a short delay before staging. The booster would be about 15 meters high at the point of staging. Also, a short piston was built into the nose of the V-2 to add some additional performance and help protect the nose of the booster.

It was simple, tricky, and effective, and in ten years of using that approach no other country ever figured out what we were doing.

Alternately, I am sure that a creative modeler could figure out how to stuff a timer and battery into a BT-80 nose cone. You may be able to steal some ideas from this thread.

James
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  #12  
Old 04-05-2020, 11:15 AM
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jeffyjeep jeffyjeep is offline
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My WAC sustainer will be static. I’m also going to defy the rocket gods and use what I have on hand: BT-5 and PNC-5. It’s not intended to be a museum piece—nor will it be. I’m already brainstorming a “now for some technique” for centering the sustainer in the PNC-80.
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  #13  
Old 04-05-2020, 01:38 PM
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sandman sandman is offline
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Quote:
Originally Posted by jeffyjeep
My WAC sustainer will be static. I’m also going to defy the rocket gods and use what I have on hand: BT-5 and PNC-5. It’s not intended to be a museum piece—nor will it be. I’m already brainstorming a “now for some technique” for centering the sustainer in the PNC-80.


OK, here is how I did it.

At the base of the nose cone there is a hole. Clean it up a bit so it is perfectly centered (as close as you can.

Get a 1/4"(or as close as you can), wood dowel about 12" or so long.

Push some of the clay nose weight that comes in the V-2 kit all the way into the nose.
The clay is to hold the dowel inside at the tip of the nose cone.

If the hole in the back of the cone is too big for the dowel, use tape to hold it in place.

Insert the dowel into the cone with one end imbedded into the clay to hold it place the dowel on a table with the nose cone sticking out over the edge.

Slowly spin the dowel with the palm of your hand and with a pencil carefully mark the tip of the spinning cone.

As you spin the cone you can easily see if it is centered.
That should work.

Now I would just use my lathe

The scale dimensions are Body tube of the V-2 is 65" model is 2.60"
The sustainer is 12" so scale gives me 0.48".

A BT-5 is 0.54" so a difference of 0.06".

No biggy.
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  #14  
Old 04-05-2020, 04:55 PM
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jeffyjeep jeffyjeep is offline
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Sage advice Gordy. Thanks!
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  #15  
Old 04-07-2020, 06:43 PM
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jeffyjeep jeffyjeep is offline
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Gordy, how did you replicate the spin nozzles?
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  #16  
Old 04-07-2020, 07:29 PM
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sandman sandman is offline
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Quote:
Originally Posted by jeffyjeep
Gordy, how did you replicate the spin nozzles?


I made them out of scrap balsa. (Boy, do I have a LOT of scrap balsa!)

I went with the design used on the Honest John. I just scaled them down to the size on Peter Alway's drawing.

Oh, and there are only two. They are centered between the conduits.

I think you can see that the conduits are aligne with the two opposing fins.
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