JETTA: Sorry.....Inflatable float is not for Sale....the way it construct is exactly the same way I describe on "How to make Cheap float"...in the Original Float, they use aluminum tubing for the 2 ROD and a wood spruce is mounted on the heli frame, the 2 aluminum rod is bolted on the wood spruce.....Coke bottle is stronger than Inflatable float.....Inflatable float is more than 25 years old, galing pa yun sa uncle ko.
Here is the Physics, a 2liter bottle can support 2 Kilo of load (assuming fully submerge yung bottle), 4 bottle can carry 8 kilo of load or can carry 4 kilo of load with half submerge bottle, you have to experiment, depend on the weight of your heli.
gawa ka na lang, masmatibay ito.....use carbon rod from Pato...and use Large nylon-tie (dami sa true value) to wrap it on the 2 Rod....and Glue gun lang....if you want, you can pressurize the bottle para matigas...use air-inlet( dami sa vulcanizing shop )....Balitaan mo ako pag-nagawa mo.