hydrogen

Discussions on high/extreme altitude and mach busting rockets.

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mulga metal
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hydrogen

Postby mulga metal » Fri Aug 11, 2017 2:47 pm

Jupiter uses hydrogen at great speeds. Light gas rail-guns could use it for reducing drag in the barrel. Then maybe to reduce rocket drag , nozzles could emit hydrogen at the front end . Boundary layer , Reynolds and laminar flow come to mind but I'm not sure what they are on a rocket hull. A petrol spill on fire spreads the fire slowly so maybe the rocket could outstrip the hydrogen burn at the tail ? Or the H2 could be used at the end of the burn to reduce drag and thus the previous final burn velocity?

mulga metal
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Re: hydrogen

Postby mulga metal » Fri Aug 11, 2017 8:20 pm

Suppose the hydrogen is released at 1mm thickness over 1 metre lift-motion . It will be most effective at the nose and less at the tail . For a 30cm wide rocket that is 1 litre / metre and .1g hydrogen. Then 30kms flight needs 3kg gas. Hydrogen density is .07 air indicating the decreased drag and less weight of fuel.

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Re: hydrogen

Postby mulga metal » Tue Aug 15, 2017 5:50 pm

@mulga
that's a bit stupid , what about the drop in air pressure at 30km ?
eh?

mulga metal
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Re: hydrogen

Postby mulga metal » Tue Aug 15, 2017 5:54 pm

Pull your head in . Sealevel is 14.7psi and 30k is .16 psi. So the 1mm becomes about 90mm , big deal. The flow can be averaged to 40mm which is enough in anyone's language.


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