Following the loss of the Blue Samurai (failed deployment) and the Oli 3 (Crops) - Oliver decided to build the Oli 4.

Oli 4 is a 2.1 inch rocket, about 4 feet long, in Quantum Tubing - the entire design was produced on SpaceCAD - and an accurate list of parts ordered from Public Misiles.

While it still took a couple of months for the build - the Oli 4 came together really neatly, and is a fantastic rocket to see. Thank you Public Misiles.

Before launching the Oli 4 - we tested the Congreve re-loadable rocket system. You can see the results of the tests here

We love these Congreve motors. They are interesting to build, don't take too long to assemble, and seem to produce high thrust.

... but you must take care to assemble them properly. And that means paying attention to o-rings, grease and correct fitting of end closures - including delay and ejection charge.

Read on, and see what happens if you make one little mistake ... with big consequences.

Oliver prepared Oli 4 for its first flight at EARS Nov 2007

Oliver - proudly posing for a photograph before the launch sequence

Preparing to press the ignition button - and waiting for the go ahead from the RSO

The camera captures the moment something is going terrible wrong. The nosecone is seen departing the rocket just at the moment of take off. This can mean only one thing ...

Our mistake: This is what happens to a re-loadeable
rocket motor if you omit the o-ring which seals the
main chamber from the ejection compartment - just
under the ejection charge ...

The motor burns up through the rocket, filling it with
black smoke and dust. Amazingly in this picture, you
can see the parachute (low down) still neatly packed
ready for deployment. At this point, the rocket is
bearly 20 feet off the ground.

The Oli 4 starts to spin around uncontrollably.

Unseen to our eyes at the time - but caught by the
camera - combustable exhaust gases erupt from the
body of the rocket.

It all happened so fast, that none of us saw this
during the event.

When we had found out what went wrong, it took
just a few minutes to clean out the rocket, load
a second motor and re-launch. The rocket was
un-harmed and flew perfectly on its second flight.

The motor in each case was a Congreve
29mm 120G70. Here it is, firing correctly on its
second attempt. It flew straight and true.

We are hoping it's next flight will be on an H.