[amsat-bb] Today's Rocket Lab launch

[Mac A. Cody]

Burns,

You are correct.  Traditional liquid-fueled rocket engines are very
complicated, due in part to the turbo pumps that feed the fuel
and oxidizer that are at cryogenic temperatures.  Traditionally,
the fuel and oxidizer are tapped to burn a small amount in a
preburner to power the turbopumps to keep the engine fed and
thrust maintained.  The plumbing to make this happen results in a
heavy rocket engine.

Using electric motors removes all of the plumbing needed to support
the turbopumps but, as you observed, at the cost of needing batteries
with enough power to keep the pumps running during the launch.  LiPo
batteries provide the power density to make this feasible.  Even still,
they have two sets and kick the spent batteries out when exhausted and
no longer needed.

73,

Mac / AE5PH

On 3/29/19 9:16 AM, Burns Fisher wrote:
> I saw most of it live.  I had no idea that they used an electric motor for
> the fuel and oxydizer pumps.  It must make the engine a lot easier to
> design and build!  And I knew someone was doing 3D printing for engines,
> but did not realize it was RocketLabs.
>
> BTW, another cool thing:  The electric pumps are powered by LiPo batteries
> (1 megawatt!!!!!!!!).  Two batteries can power about 1/2 the (1st stage)
> flight and then they "hot swap" to a second pair and drop the first pair to
> reduce wait.  Very cool!
>
> On Fri, Mar 29, 2019 at 8:58 AM Paolo (IK8XOO) via AMSAT-BB <
> amsat-bb at amsat.org> wrote:
>
>> TNX, but the video seems to be not available.
>>
>> 73s.
>> Paolo IK8XOO
>>
>>
>>
>> ----- Original Message -----
>> From: "Wendy and Terry Osborne" <wandtosborne at gmail.com>
>> To: <amsat-bb at amsat.org>
>> Sent: Friday, March 29, 2019 2:19 AM
>> Subject: [amsat-bb] Today's Rocket Lab launch
>>
>>
>>> Launch successful
>>> See: https://www.youtube.com/watch?time_continue=5&v=OaUSf0D95vs
>>>
>>> Watch out for the next launch in April.
>>>
>>> 73,
>>> Terry Osborne ZL2BAC
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> _______________________________________________
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