## Missile Construction Question

R/C Submarine modelers

### Missile Construction Question

Hi All!
I have been trying to follow the June 1995 Issue 21 article by Mathew Spade on constructing missiles. In the article he writes "Next, drill a 1/6th inch hole in the bottom of the missile and slightly counter bore the hole." If my calculations are correct, 1/6th inch hole is .166 decimal or a #19 drill. This seems very large to me. Has anyone actually built a missile or missiles following this article and is this a correct and valid size hole or did I do something wrong?

Thanks, Ed
Just one more wire!
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Ramius-II
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Ed,

1/16th inch is 0.062.

B^)
"If you ignore the problem long enough, it will go away. Even flooding stops eventually!"

wlambing
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Thanks and the article says one-sixth of an inch which seems very large.
Just one more wire!
SC# 2268
WB6NSN

Ramius-II
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Ed,

I just reread the article. I think we have a recurring typo for that fraction! Some thought food; There's butt-tons of 1/16 stock in our little universe and I suspect only two lengths of 1/6, stored somewhere in the vaults of Lower Slobovia. I also supect those pieces are made of Nonobtainium. ;^)

If the hole (nozzle) in the bottom of the missile is much bigger than 1/16 you'll not get too very much thrust from the gas expanding through same.

Take care,

Bill
"If you ignore the problem long enough, it will go away. Even flooding stops eventually!"

wlambing
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Hi Bill! Thanks. Where I get confused is when I look at the pictures in the article it looks just as you said, about 1/16th inches. I was given some Estes rocket motors (1/2A6-2) by my neighbor and the exhaust holes are about 1/6th of an inch! My intent is to incorporate the proper size o-ring in the tail of the missile as a seal against the "pin". Here is a drawing of the missile with a 1/6th hole. What do you think?

Best, Ed
Just one more wire!
SC# 2268
WB6NSN

Ramius-II
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### Give Matt a call

Guy's - You might just give Matt a call. He's always been willing to help others. The last phone number I have for him is (770) 929-1945. You won't find a better man. Best Wishes..... Mike Dory
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Ed,

I thought you were going with a gas ejection system. Matt and Dr. Art Broder have good experience with missiles. If you're going to use Estes motors, that's a whole different world. I remember years ago when Loren Perry burned the bow of his USS Long Beach (CGN-9) using the smallest Estes motors for A/A missiles. It was sad!!

Good luck, I'm going back to sleep now!

B^)
"If you ignore the problem long enough, it will go away. Even flooding stops eventually!"

wlambing
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I seem to remember watching a video where Mike was talking about how his rocket motor missile went through some lady's house and ruined her carpet.... Dont quote me.

Bill I am the one using a gas ejection system.
Kevin
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Hi Guys!
Thanks to all. Yes, I am using a gas system and I was only looking at a rocket motor to see what size Estes used. The plan is to incorporate an 0-ring seal in the base of the missiles.

Best, Ed
Just one more wire!
SC# 2268
WB6NSN

Ramius-II
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Kevin,
I know you're using gas. That's why I'll have my trusty and faithful MK V mask with the heavy duty cartridges installed!!!!

B^)
"If you ignore the problem long enough, it will go away. Even flooding stops eventually!"

wlambing
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Joined: Fri Feb 21, 2003 5:59 pm
Location: Ledyard, CT, USA

Hi All!
First, thanks Mike I called Matt Spade, we had a great conversation and I learned a lot! He sends his greetings and best wishes to everyone. The answer is 3/32" or .09375. Matt started with 1/16" and found that 3/32" worked better. For all those developing missiles, one piece of valuable info is that a missile will work very different when launched from underwater than in plain air. "In plain air a missile will appear to be very disappointing, while launched from underwater will work amazingly!"

Best to All, Ed
Just one more wire!
SC# 2268
WB6NSN

Ramius-II
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As you may or may not know I have been makin a missile system for my ohio. Here is a look at how it works so far. I have been launching the missiles using 60psi and liquid air for propellant in the missile. The cylinders are 4" long and about 3"- 2.5" nominal gas space inside. Overall Missile length with balsa nose cone is 5". The exhaust port is 1/16" with a taper bore nozzle and o-ring seal. For my testing I am using air from my compressor to launch, later I will use propel on board, which has a pressure of about 70psi at around 70 degrees F. Right now I am test launching out of a bucket and getting small heights. To increase my height I am going to reduce weight by cutting down on bulkhead thickness. this will not only increase my gas volume but also decrease weight. A 3/32 nozzle is also interesting. Now for some photos and a movie!
Sorry If I jacked your thread Ramius I will move it if you like

Kevin
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Kevin
A Global Force For Good

http://WWW.ROGUESUBWORKS.COM

Rogue Sub
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Kevin with increased gas volume.... great....
expfcwintergreen

Yeah believe it buddy as you type at this moment I am killing the dogs.
Kevin
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