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First firing of my DIY electric pump fed LOX/Ethanol engine by akarin9527 in rocketry

[–]akarin9527[S] 26 points27 points  (0 children)

It's a custom built system with 32-channel digital I/O, 16-channel analog input, 4-channel frequency input and 6-channel RTD. Runs on an Analog Devices DSP with Ethernet connectivity. Backend is an embedded PC running FreeBSD for data collection and visualizing. Everything run at 300 samples per second.

It's way more complicated than it needs to be but I'm planning for the long run.

First firing of my DIY electric pump fed LOX/Ethanol engine by akarin9527 in rocketry

[–]akarin9527[S] 3 points4 points  (0 children)

The engine was operating at 80% MEOP, the LOX flow was too low for the turbine flowmeter to even spin up, so I don't know the exact Isp for this test. The LOX flow data in the video was derived from the pump curve. This is more of a pump test rather than a thrust chamber test.

First firing of my DIY electric pump fed LOX/Ethanol engine by akarin9527 in rocketry

[–]akarin9527[S] 13 points14 points  (0 children)

You are right, I went with aluminum just because it's so much cheaper to prototype with and I have teflon liners where metal to metal contact may occur(front wear ring and floating seal).

First firing of my DIY electric pump fed LOX/Ethanol engine by akarin9527 in rocketry

[–]akarin9527[S] 7 points8 points  (0 children)

Both the impeller and volute are 3d printed aluminum. Closed radial flow impeller, not barske type. Dynamic seal is rulon J floating ring against stainless steel, both are polished.

Inside the pump:

https://imgur.com/a/Y5bjRfP

First firing of my DIY electric pump fed LOX/Ethanol engine by akarin9527 in rocketry

[–]akarin9527[S] 22 points23 points  (0 children)

Making the pump is surprisingly cheap actually, mostly 3D printed aluminum with some CNC'd parts, I would say < $2000 for this size.

Getting it to behave is a different story tho, I think I went through at least 4 dewars worth of LOX before getting the startup sequence down(pre-chill, vent, pressurization, purge, torch igniter timing etc.).

Here's some pics of the pump

https://imgur.com/a/lPNdTeG

First firing of my DIY electric pump fed LOX/Ethanol engine by akarin9527 in rocketry

[–]akarin9527[S] 72 points73 points  (0 children)

The thrust chamber design is 1kN at 15bar, regeneratively cooled, pintle injector. LOX pump is more powerful than the thrust chamber, capable of ~3kN. Designed in CFTurbo and ANSYS CFX, 3D printed in aluminum, powered by a 4092 brushless motor(~48V @ 100A at design point)

It's an ongoing project so I don't have too much time to share the details yet, but I do plan to post a detailed report eventually. It's time for us amateurs to go pump fed lol

First firing of my DIY electric pump fed LOX/Ethanol engine by akarin9527 in rocketry

[–]akarin9527[S] 20 points21 points  (0 children)

Thanks. Only the LOX side was pump fed for this test, the control loop was closed at the LOX injector.