CS Looking at Electric Pumps

I have to be a little picky with this video, the masses given comparing pressure fed to electric fed could have been more detailed. In amongst those numbers, I assume is battery weight which would have been nice to know.
If they intend to use Li-Pos and if they want to reuse these they can only really go down to 3.0 volts per cell, or else damage occurs. Others using Li-Pos to power pumps I have heard go down to 2.8 volts per cell, but as this is in an expendable rocket, it does not matter as much. So a bit more care and extra battery capacity may be required to be able to operate safely, which is, of course, more weight.

There is also no deltaV comparison, which is really the only important number you are designing for when trying to reach space, in this case, 105 km altitude.

Where,
Ξ”v = Velocity change (deltaV)
Isp = specific impulse
g0 = gravity
m0 = Initial mass (with propellant)
mf = Final mass (without propellant)

The comparison also does not state the chamber pressure of the engine, I assume the electric comparison uses the same chamber pressure as the pressure fed. But as stated, the whole point of a pump is to decrease your tank mass and increase engine chamber pressure which in turn increases your engine Isp, your deltaV and decreases engine mass (theoretically). The question then is, what chamber pressure can you reliably design and manufacture for?
One must take into account the higher heat flux and added cooling requirements also.

The COTS or common of the shelf components I have to also argue, you are never going to be able to buy a pump off the shelf that will match your mass flow and pressure requirements, let alone material compatibility. Electric motors and speed controllers you may be able to, which will speed up development, but you will probably have to make modifications to make these flight-ready anyhow.

All in all, I can definitely see the advantages of looking into this pumping method for such a project, and it is great they are open to it.
I just wish the video lived up to its name more as we do not really get a good comparison between the two systems.

Instagram Pic of the Week

View this post on Instagram

We are looking forward to test this electric turbopump from Orbital Machines on Spica's BPM100 rocket engine later this year! Check them out and follow them for development updates, if your as excited about this as we are! πŸš€ #Repost @orbitalmachines Hello worldπŸ‘‹! @orbitalmachines is building electric turbopumps πŸŒ€ for small to mediumsize rocketmotors. They will help build better, cheaper, and safer launchvehicles for the newspace industry. πŸš€πŸ‘©β€πŸš€πŸ‘¨πŸΎβ€πŸš€πŸ€–. We are a 100% crowdfunded spin-off of the amazing @copsub project which is going to shoot 1 space enthusiast into space soon! If everything goes according to plan our pumps will undergo the first test on the #bpm100 engine this summer. stay tuned! πŸ‘©πŸ»β€πŸ’»πŸ‘¨β€πŸ’»πŸ‘©πŸ»β€πŸ”¬πŸ‘¨πŸ»β€πŸ­πŸΆ #electric #turbopumps #newspace #rockets #launchvehicles #space

A post shared by Copenhagen Suborbitals (@copenhagensuborbitals) on

PSAS Pump Work

Portland State Aerospace Society continues to develop their electric driven propellant pump.

https://twitter.com/MechBertrand/status/890020812350148608

https://twitter.com/MechBertrand/status/890024023865737216

Video: Bagaveev Corp Electric Driven Rocket Pump Test

The Bagaveev Corporation, have been recently testing an electric driven centrifugal rocket engine pump, as discussed in this post here, the below video shows the pump being tested at cryogenic temperature levels with liquid nitrogen. No stats on the design or performance are known, but it is good to see pump work development at this scale going on.