The Blimp Gondola

The blimp gondolas are made of lightweight plastic 'blister packs' which are commonly found holding products to cardboard backing. Many different products are packaged this way and it was just a matter of finding something that was the right size and weight for the job at hand. The gondola is attached to the envelope with 'Sellotape', which is lightweight and gives a good bond that will not damage the nylon envelope when it is removed.

The 'Jaffa MK1' uses the packaging from 'Mini Jaffa Cake' biscuits and provides enough space to hold all the electronics and batteries. Balsa wood arms fixed to the plastic housing using hot melt glue attach the motors to the gondola.

The 'Jaffa MKII' gondola uses the same plastic blister pack from but has been lightened by trimming any unwanted plastic and weighs less than the MK1. It also differs from the MK1 in that the arms holding the motors are made from plastic drinking straws that weigh half as much as the equivalent balsa structures and being plastic they bend instead of snapping should they hit something. The plastic straws are flattened at the ends, bent around the motors and heat welded, giving a firm fixing point that requires no glue or clips. This glue-less design maximises the weight saving.




The main drawback of using small blimps is the severe weight limitations placed on the design of the electronic control system: the net lift of the inflated envelope is only 93g and more than half of this (50g) is to be used for batteries. All the circuits are manufactured from 0.5mm fibreglass board, which is one third the thickness of a standard circuit board. This thin board coupled with the very compact layout and the use of surface-mount technology helps to reduce the weight by a considerable amount. The only problem with such a small and compact design is that assembling it by hand is a very intricate task, which requires considerable concentration, good eyesight and a steady hand. The boards have to be thoroughly cleaned after each component is soldered in place to prevent the build-up of small solder balls, which are difficult to see and can get trapped between pins causing short circuits. The picture below shows the bare printed circuit biscuit which contains all of the blimp circuit boards. It is much cheaper to put all the separate circuits onto one biscuit and then make multiple biscuits. The image map below will show you all the various circuit boards fully populated.

The electronics are split into two distinct parts; digital and analogue in order to minimise the coupling of noise from the digital board to the much more sensitive analogue boards.

single sensors 3sens tx360 tx180 reciever control