UAVs / competition models box bladder tanks

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  • Regular price $380.00

These are quality certified, low cavitation square bladder tanks designed to fit industrial UAVs and competition models.

When ever legal or possible, we highly recommend the use of bladder ssytems for your jet or piston powered UAV.

The reason for this is that these systems are air free. This allows to feed the engine with no risk of air bubble ingestion at any point of the flight, in any position and supply a continuous positive flow of fuel ( atmospheric pressure pushes on the bladder at all times ). This is turn allows the removal of air traps, which saves a lot of complexity, risk of failure and about 1 to 3 lbs of dead weight.

These bladders are best suited to fit fuselages ( square shape ) or wing ( trapeze shape )

These tanks are available in many sizes. Dimensions can be custom designed on request. Example of sizes are as followed ( maximum length 80 cm ):

25 liters fuselage ( rectangular 61 cm by 48 cm outer size/ 21 cm height when inflated)

20 liters fuselage ( rectangular 54 cm by 46 cm outer size/ 20 cm height when inflated)

15 liters fuselage ( rectangular 51 cm by 42 cm outer size/ 18 cm height when inflated)

10 liters fuselage ( rectangular 44 cm by 38 cm outer size/ 16 cm height when inflated)

7 liters fuselage ( rectangular 40 cm by 34 cm outer size 14 cm height when inflated)

5 liters fuselage ( rectangular 34 cm by 32 cm outer size/ 13 cm height when inflated)

4 liters fuselage ( rectangular 32 cm by 30 cm outer size/ 12 cm height when inflated)

3 liters fuselage ( rectangular 25 cm by 22 cm outer size  11 cm height when inflated)

2 liters fuselage ( rectangular 22 cm by 22 cm outer size/ 8 cm height when inflated)


20 liters fuselage ( trapeze base 54 cm by 46 cm outer size/ 20 cm height when inflated)

15 liters fuselage ( trapeze base 51 cm by 42 cm outer size/ 18 cm height when inflated)

10 liters fuselage ( trapeze base 44 cm by 38 cm outer size/ 16 cm height when inflated)

55 liters fuselage ( trapeze base 34 cm by 32 cm outer size/ 13 cm height when inflated)

They are designed to work as a non vented/ air-free system.

( 4 liter fuselage square bladder seen below )



Each bladder is custom built to your specifications ( please contact us with your maximum compartment dimensions and desired fuel capacity ). It is made from a single layer or double layer specialized membrane ( specified for lifetime kerosene resistance and weldability ) as well as viton tubing.

The welds consist of 2 zones of 8 mm fused material with a 4 mm gap in between. This allows to spot a weld failure ( fuel injection in the buffer gap ).


Bladder internals are cavitation optimize and comprise of the following:

1 Large internal bore aluminum fuel manifold inlet port, fed by an air separator filter ( up to 20 mm output port for fast jettisoning ). This act as an integral air trap.

1 Large internal bore fuel fill/ air bubbles drain port. This port is connected to a dual loop air breather tube system that collects the air bubbles during the air purging sequence of the fuel fill and prevents vacuum lock at low fuel levels.


Cavitation is avoided by providing a slight positive feed to the pump due to the fact that atmospheric pressure pushes on the soft layer of the tank.

Also, our bladders are designed with high flow in mind and all tubings, stoppers and fittings in the systems have the same internal bore of 4, 5, 6 or 8 mm depending on the bladder capacity or customer request.

All the internals are safety wired with chromel wire that is covered with a heat shrink tube for scratching/ cutting prevention.

The fuselage bladders incorporate 2 channels and a set of carbon tubes that are used to suspend the bladder between bulkhead ( see product picture ).

The wing bladders are best fitted with velcros set on the lower skin and will remain in position by gravity in the wing compartment.

All the ports are fitted with industrial grade Pisco push-to-connect fittings in 4 mm, 6 mm , 8 mm, or 10 mm OD.

These bladders are supplied with a professional operations manual as pdf file. For plumbing and general fuel system considerations, please refer to our blog: fuel systems for UAV and RC jets considerations

These are pressure tested at 1 bar for 1 hour and quality certified. They come with a quality certificate.

This product cannot be fitted in RC models in the USA and Canada as not AMA legal.