FERRYAIR Posted January 13, 2015 Share Posted January 13, 2015 Before taking my Thread too seriously I am just hyperthetically asking the question If someone was to fill up their Aerofoil wing with Helium balloons would it hyperthetically create added lift? I know it sounds silly but my inquisitive mind regularly thinks up these crazy thoughts. The discussion is the byproduct of a few of us discussing buoyancy of microlights in a ditching..... Using PET Lemonade bottles in the inside of the wing gives a 2kg buoyancy per 2 litre bottle inserted ( 300kg = 150 bottles ). The weight of 150 PET bottles is actually 8.4kg so 155 is actually needed to keep 300kg buoyant however the fuel tank is also buoyancy in a ditching. Polystyrene was also discussed as for every kg of buoyancy the litre of polystyrene weighs 17grams as opposed to the 23grams per litre a PET bottle weighs. To get 10kg of buoyancy with polystyrene you need a 109cm x 20cm x 5cm slab of polystyrene ( 30 sheets of 109cm x20cm x 5cm will keep 300kg afloat ) again the fuel tank will offer buoyancy ( B&Q do these sheets at £1.00 each, so £30.00 for peace of mind ) Quote Link to comment Share on other sites More sharing options...
Guest Posted January 13, 2015 Share Posted January 13, 2015 Anything that reduces the in flight weight of a given wing surface will increase the lift. so the answer is yes for sure. But it will fly slower:-) SW Sent from my iPhone using PMC Forum mobile app Quote Link to comment Share on other sites More sharing options...
ptwizz Posted January 13, 2015 Share Posted January 13, 2015 So long as the boyancy of the helium in air (about 1.1grams per litre) offsets the weight of the gas bags, you would reduce the effective weight of the aircraft. The relatively small dimensions of the wing pockets would force the use of small gas bags, so the ratio of bag material to helium would be poor compared to a simple balloon containing the same volume of helium. So, broadly yes, you could add some bouyancy by filling the wing pockets with helium balloons. I'm guessing there could be a range of issues associated with obstructing the movement of air within the wing, the way the wing is launched, the way it moves in response to control inputs, the way it recovers from 'aerodynamic incidents' etc. Quote Link to comment Share on other sites More sharing options...
gordon_dunn Posted January 13, 2015 Share Posted January 13, 2015 Before taking my Thread too seriously I am just hyperthetically asking the question If someone was to fill up their Aerofoil wing with Helium balloons would it hyperthetically create added.... Yes would in theory create additional lift, but wouldn't be in any way practical. It's arguable that it may make launching a bit easier..... but i'd say an inflatable envelope/wing would equally be effective. Besides the core principle we have at the moment is an inflatable wing, only it's inflated instantaneously at launch- by the movement of the wing. I'm all for new ideas, but dont think this would get off the ground- no pun intended. Besides, what about the potential helium shortage???? http://www.dailymail.co.uk/news/article ... ntist.html Quote Link to comment Share on other sites More sharing options...
gordon_dunn Posted January 13, 2015 Share Posted January 13, 2015 Check this out- very interesting http://aerosociety.com/Assets/Docs/Abou ... hoenix.pdf Quote Link to comment Share on other sites More sharing options...
spigot Posted January 14, 2015 Share Posted January 14, 2015 I think you all should get out more [FLUSHED FACE] Sent from my iPhone using PMC Forum mobile app Quote Link to comment Share on other sites More sharing options...
ptwizz Posted January 14, 2015 Share Posted January 14, 2015 Very interesting paper on the Phoenix inflatable. It is mentioned that it contains 200lb of air. replacing some of that air with hydrogen would reduce mass (allowing faster acceleration) and weight (allowing slower flying). Hydrogen is preferable to helium as a lifting gas for many reasons. The perception of fire risk is misplaced. Quote Link to comment Share on other sites More sharing options...
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