MarcCallaghan

Folks, I need some advice and guidance.

 

First, some context:

I'm a 'techi' teacher and wish to knock up a few small rocket engines with which the kids can simulate a rocket car - essentially the Bloodhound Challenge. So the kids will make small model cars which will roll along the deck and be tethered to a static line in order to keep them in a straight line.

The kids will make the cars but only I will make the rockets, fit them to their cars outside and light them once the kids are away a safe distance.

 

Materials:

I purchased some fuse, Pottasium Nitrate (KNO3) and some icing sugar.

 

Method:

I mixed a ration of approx 70% Pottasium Nitrate to 30% Icing Sugar. I measured quantities by weight and added a pinch of Iron Oxide. I then gently warmed it up over a hot plate until i got a rough syrup consistency and then packed it into a thin plastic waste pipe (approx 1inch x 3.5inches ). Once cooled, i blocked both ends with a filler (like polyfiller) and then punched a hole in one end using a screwdriver.

 

Result :

Pretty poor. I wedged the rocket motor between 2 weights and lit the fuse. It started fine but seemed to create more smoke than thrust. Half way through the burn the pipe also failed and turned into a molten mess.

 

Request:

I need some guidance. I'll soon have 30 kids, each with a model (approx 12inches long and made from covered foam and balsa, etc). All desperate to see their car whiz across the tennis courts and my best efforts resemble wet farts. I'm going to get lynched.

 

Oops, almost forgot. Before someone suggests buying the commercial ones. Their like rocking horse poo in our neck of the woods and even if i could get my hands on them, we couldn't afford them.

 

Thanks

 

 

Marc

Hi all,

I've joined the forum hoping to gain a bit of advice, knowledge and help. I run a technology department in a Scottish secondary school (in Ayrshire) and intend to start a model rocket club. A club in which the kids can come and build their design under supervision, be supplied a rocket motor and fly/test them in the school grounds. Fortunately we are in quite a remote location so there's plenty of space away from homes and roads to fly.

I did run a similar club a few years back, whilst teaching in Essex and the kids generally loved it. At that time we bought inexpensive solid rocket motors from a company named EuroCraft who have unfortunately since stopped trading. At the time we were buying them in at £5 for 10. They weren't very powerful but they were cheap.

Problem: Funds are very tight, what with budgets being slashed and the boss isn't overly concerned with extra clubs when he's struggling to simply pay wages. Also the motors currently available on the UK market seem awfully expensive.
I had decided to make some simple pottassium nitrate:castor sugar rockets ourselves and offer them to the kids at cost price but am having a real problem sourcing the pottassium nitrate. I can source the 'pure' stuff through the science dept. but it's very expensive and a waste as i don't need it to be so pure. I have called into a number of large gardening centres but am immediately made to feel as welcome as a root canal when i ask for the pottassium nitrate fertilizer.

Can anyone help? I essentially need a supplier where i can buy the occassional medium/large bag of pottassium nitrate without incurring a massive postage fee or being made to feel like a criminal when asking.

Also, i'd be grateful for any advice concerning designs and materials suitable for young kids (12-14yrs old).

Thanks

Marc