[AR] Re: Continuation of small hybrid motor design
- From: Peter Fairbrother <peter@xxxxxxxxxx>
- To: arocket@xxxxxxxxxxxxx
- Date: Sat, 25 Jul 2020 12:42:27 +0100
On 23/07/2020 22:02, mark.spiegl@xxxxxxxxx wrote:
ken mason wrote:
>> [N2O thermal equilibrium]
Very interesting.. you are the first person other than myself to
acknowledge this issue as serious.
I have struggled with N2O temperature striations over and over and over
again. Almost always, my goal is heating the N2O, not cooling it.
Isn't that easy? Just an electric warmer, or warm water if you want
overtemperature control? If it is on the right place you could get
convective mixing?
Or am I missing something?
I have
played with a few possibilities:
-A collapsible rain barrel filled with ice for the supply tank.
-Paint the rocket or static tank black to get help from the sun.
-A magnetic object inside the tank, moved by an external magnet. (like a
chem lab magnetic stirrer on steroids)
Two thoughts here: first, most tank materials are non-magnetic, so you
could make an eg ptfe rotor for a brushless motor to go inside the tank,
with the stator outside the tank. As the power requirements and speed
are minimal a large gap or some Al sheet between stator and rotor won't
matter.
The rotor should have a hole in the center so it doesn't affect
operation of the rocket. It could also have fan blades on the inside and
outside to stir things. You could also move it up and down the tank by
moving the stator up and down.
You could also attach it to a long thin stirrer. No seals required.
Or, for very tall thin tanks, just put any tank-safe magnetic object
inside the tank. To stir, simply move an external magnet up and down the
tank, a bit like using a fishtank cleaner. Not perhaps as effective, but
simpler.
Peter Fairbrother
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