Second Stage Ignition Device

Second Stage Ignition Device- Click to enlarge

How will it work?

The main components in this design are the burnout detector, the SCR component, and the 555 timer circuit.

When the rocket takes off under the power of the 1st stage, everything is moving at the same velocity –including the steel ball. Once the 1st stage motor burns out, it causes the rocket to stop accelerating and due to air resistance the rocket begins to slow. However, the steel ball does not slow down as quickly as the rocket because there is no air resistance to affect it. So, the steel ball travels forward (up) and closes the switch. It's like holding the brake while going fast - u travel forward. In this case the air resistance is the brake on the rocket's body.

That part of the gadget was derived from Alberto/Dan Polino's Apogee detector.

The SCR now comes into play. The SCR is a semiconductor that can be configured as a switch. What makes this switch so special is that once it is turned on, the SCR will remain on even if the switch (steel ball switch) becomes open. This is crucial in triggering the timer and maintaining that voltage to the timer

The timer’s responsibility is to delay the ignition by (X) amount of seconds. This is needed to take advantage of a coasting period to attain maximal altitude before igniting the second stage. This second stage must be ignited before the rocket begins to slow too much. And that is basically how this contraption works - in theory

2 Stage Sugar Rocket - Category 5 Hurricane

A two-stage rocket derived from the 'Hurricane' is currently being designed. This rocket, called the 'Category 5', features two I-350 motors that should propel the rocket well over 7500 ft. Clearance will be sought from the CAA before this is launched.

Here is the current design.

You may be wondering why 2 similar motors are being used instead of the traditional big booster -> smaller sustainer setup. The reason lies in the fact that the biggest motor this tube can take is an I-350 sugar PVC and based on simulation in Open Rocket the motor seems to be strong enough to lift the extra weight of the upper stage with ease.

Material / Components List (so far) - sans motors

• 1 and 1/2 blueprint tube or a full length fabric tube
• 2 small umbrellas 
• 1 large umbrella
• 2x 1^.25 PVC end caps for bulkhead and ejection plunger
• Nosecone made from body filler
• 1.5 inch PVC drain pipe for couplers and nosecone neck
• Solitex or MDF wood based Clipboard  - for fins
• Screws? I forgot the size they are but I know i need 8 1/8 Self tapping screws
• 2x 1/4 inch machine screw for launch guides - the head of these are big enough to function as buttons

...more to come

Thunderbolt Rocket - Launch

Here it is my friends:





The motor was actually nearer to an I-350 spec, not an I-400. All in all the flight was successful notwithstanding the main chute releasing a little earlier than planned. I’m not sure how but I’m guessing the nosecone was shaken off the tube and eventually pull the main chute out. This “thunderbolt rocket” is heavier than the “hurricane“ so the apogee as lower.

A remake of the Hurricane will be flown soon, painted in pink (for that special lady who will be present)
Can't wait!