Good morning Connecticut!

 

Morning Jim cold out their.

 

Good Morning Jim, Andy, and everyone else!

 

They say 10*, but it didn't feel that cold when I was out around 5:00.

I have some shoveling to do but no real work today.

 

morning everyone

 

Not quite Astronauts.

Here's an old picture of me with what was to be my L3 rocket in my backyard.




(Sorry for the image quality, it's a scan of a 12 year old photograph)

 

Good morning CT...kind of chilly this morning!!!

 

jim what does that thing use for fuel, and how much does it cost? i remember using d-cell sized solid fuel when i was a kid. i think we could adapt your gigantor rocket to make something fly at the salt flats!

 

Aaron, We already have flights at the Salt Flats as well as Black Rock Desert & Mojave.

It uses Ammonium Perchlorate Composite Propellant. (the same thing as the Space Shuttle's SRB's)

It is 6" in diameter and 14' tall, and fly's on K-M impulse motors.
The largest I've ever built (but never flew) was 12" in diameter and 24' long.

 

Jim:

The largest hobby rocket motors that I can recall were a Letters D & E - or - E & F?

I think they could produce a pound of thrust?

They were made by Centurian?

I might still have all these old 1970's catalogs in storage.

What became of that flying machine?

Is it the 24 footer you mentioned here?

 

Good evening everyone.

 

how far in the sky would that rocket travel?

 

Hi Everyone!
Ok, I'm going to try and address all this without multiquotes because of my pi$$ poor keyboarding skills.

1) Right. Each impulse letter is twice the total thrust of the previous one. So, a "B" is =2 "A's" and so on. The largest commercially certified motor at this moment is an "O" (you do the math to the 15th power)
2) Centuri manufacturing was bought up by Damon Corp which also owned Estes for a while.
3) Another member of my club who has more money than me now has it and flies it on occasion.
4)No, it is the 6" diameter x 14' one. The 24' tall one is a scale model of a Black Brandt II sounding rocket.
Black Brant Project - Home
5) The one you see in my picture has flown as low as 1300' on a K-1100 and as high as 18,000 on an M.

 

Jim:
Do these rocket motors become more economical as they get larger?

Like an L is double the thrust of a K, but maybe not double the cost?

 

To some extent, yes.
But when you get much above the H-I class they become "Reloadable" Where you own an aluminum case and end closures then purchase different formulations of propellant and nozzles to fit that case.
Standard diameters are:
38mm (1 1/2")
54mm (2 1/8")
75mm (3")
98mm (4")
150mm (6")
Lengths vary

Propellant mixes can be:
White smoke
Black smoke (fast or slow)
Red flame
Yellow "
Orange "
Blue "
Green "
Purple "
Sparky (with or without smoke)

Ammonium Perchlorate Composite Propellant is classified as a low explosive by the BATFE, So it's never cheap.

As an example, a J class commercial reload is $40-60, K $70-125, L $140-250, M $3-600.

There are also people who blend their own propellant, but a whole other set of rules applies to manufacture.