Once / while pressurized...
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On Sep 2, 2016, at 6:01 PM, Lars Osborne <lars.osborne@xxxxxxxxx> wrote:
I am not going to have tanks be load bearing for obvious reasons
Why? load-bearing tanks are very common. Being pressurized will increase
stiffness, and resistance to buckling.
Thanks,
Lars Osborne
On Fri, Sep 2, 2016 at 4:02 PM, Zachary Martinez <znm3m8@xxxxxxx> wrote:
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On Sep 2, 2016, at 16:41, George William Herbert <george.herbert@xxxxxxxxx>
wrote:
Bill is correct, but you get very fragile rockets and minimum gauge
problems this way.
Not impossible, just... Be careful.
I am not going to have tanks be load bearing for obvious reasons, but I will
still have to check to make sure I still have a decent factor of safety
against buckling during expected g loading. Using aluminum rather than
stainless should help as it increases the wall thickness.
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On Sep 2, 2016, at 12:04 PM, William Claybaugh <wclaybaugh2@xxxxxxxxx>
wrote:
Zachary:
You can do as little as 50 psia against vacuum and 150 psia to sea level
air; look into Bob Truax's Sea Dragon work for reference.
That said, note that he was planning on using Lox / LH2 to recover the
lost Isp. But as a general rule mass fraction improves as the operating
pressure of a pressure fed liquid drops...and mass fraction has an
exponential effect on performance, whilst Isp is merely linear.
Bill
On Friday, September 2, 2016, Zachary Martinez <znm3m8@xxxxxxx> wrote:
Hello all,
Are there any issues operating at a relatively low chamber pressure for
an engine ~180-220psi other than the poor Isp. For a pressure fed rocket
with a relatively high thrust to weight ratio the benefits of using a
lower chamber pressure are really tempting, but I imagine there are some
design challenges that I am unaware of. My main concerns are difficult
ignition or possible flame out but I don't really know.
Thank you,
Zachary Martinez
Aerospace Engineering | Missouri S&T
