New 3\" avionics bay for Uncle Bob - (The name of this rocket) and an up and coming rocket called Aunt Sally.

Another shot of the Avioics bay - x2 RDAS, x2 battery packs - 9,6v, RDAS telemetry downlink board and transmitter, X-Y accelerometer, Iginiter expansion board, x2 rotary swirches, x2 RDAS, magnetosensor, GPS board and GPS active antenna.

A close up of some of the \'gubbins\'

A close up of the GPS active antenna inside the forward seal of the avionics bay.

The avionics bay with the forward seal in place and the rear coupler tube in place (Note: The rear coupler will ultimately be fixed to the 3\" diameter body tube. Removal of the botto bulkplate enables sliding the whole avionics assembly out of the airframe for ease of turn-round.

Booster internals: Note the service tunnel running the length of the booster. Two channels will command first stage booster separation and second stage motor ignition, respectively. Also note the load bearing coupler mounted on top of the motor mount, the forward surface of which will fit square against the bottom of the avionics bay.

Forward booster section: Internals and U-bolt attachment. (There was a grander plan to have a removable U-bolt bulkhead – given the use of the fireball. I’ve since gone back to basics – all of this structure shall be fixed in place in the body tube {shown} with glass re-enforced 30min epoxy. The impact in weight will be minor however, the extra axial strength may prove useful given a shallow second stage apogee may impart significant loading at apogee.) Drogue less first stage recovery will be employed BTW.

Fin retention wells: The balsa fillets have been shaped so the retention well forms an hour glass shape (albeit it doesn’t show on this picture at all – believe me they are there!!!). The purpose is to generate a continuous internal fillet on both the motor tube and the internal radius of the external body tube. With appropriate surface preparation on the G10 fin roots this should generate a robust fin mount.

The ‘internals’ laid out on the floor. Note: from top to tail there is a continuous internal structure (in addition to the external body tubes). This will enable the airframe to withstand more axial loading but more importantly present a significantly more rigid structure, when compared to the conventional use of just PML tubing. Also worth noting is that the forward internal coupler has not yet been cut and squared to size.

Another look at the internal structure. The tin foil used on the bulkheads in the avionics bay is apparent here.

Another look at the internal lay out: it is worth noting that the avionics bay (apart from being extremely stiff – it uses four 4mm steel threaded rod in its construction) has been built as a primary load bearing structure. The outer body tube at the fore of the airframe need only contribute to overall stiffness and a portion of the nosecone axial flight forces.

volt vs. time Bob avionics

1o stage booster

frontal Sustainer - Bob

Inter-stage coupler -coupled

Profile Sustainer - Bob3

Sustainer and Booster Bob

sustainer boatail decoupled from interstage coupler

Two Stage Bob

Wiring access for booster ejection and 2o stage ignition