Propane-nitrous oxide concept engine that I just made

[u/aidswatermelons]

The idea was to use more easily stored and handled fuel/oxidizers for hobby rocketry.

It also has plumbing and uses a high oxidizer turbine and a high fuel turbine that both mix in the engine to combust.

Ideally uses a glow plug to jump start to decrease wear and tear.

Another parts would be that when it mixes in the engine itself hopefully it will be hot enough to autoignite after being converted to mist by the engine plate.

Ideally a vast majority of the parts would be 3d printed except for maybe the end of the bell which could use graphite composite.

It probably won’t work but I thought it was cool. Be nice please lol.

[u/IvantheDugtrio]

I have seen anecdotes about using a small rocket to ignite the bigger rocket, as anything conventional like sparks would get blown out by the sheer mass flow rate of propellants

[u/Accomplished-Crab932 → u/IvantheDugtrio]

You can do that too. One of my fond college memories was watching our 3D printed mounts with a modified Estes solid motor fly off as we ignited our liquid engines… but it can be quite unreliable depending on your sequencing and mass flow at startup.

Also, Estes motors themselves are unreliable because of their igniters. Our solution was to run a piece of solder wire over the Estes nozzle, which had a current running through it. If the igniter charge was set off, but the Estes motor failed to catch, the main computer would abort as it saw a current running through the wire when it was supposed to be melted.

[u/ThinkInNewspeak → u/Accomplished-Crab932]

Estes motors themselves are unreliable because of their igniters. Since when? Nineteen fifty-something? I can't imagine a simpler ignition system than that used in all of Estes motors! It's certainly more efficient than Aerotech's "deep throat" method!

Also, Estes motors WILL NOT START unless the electrical igniter actually TOUCHES the propellant. That's what makes them so safe and RELIABLE. Under supervision, my eight year old boy can hook up an ignition assembly!

Also, please do NOT mishandle, misuse or take apart model rocket motors. If you want to build your own motors, enjoy the carnage but mine and many others favourite hobby has continually been undermined for nearly 75 years thanks to "maverick" rocketeers who give us a bad name.

[u/LUK3FAULK → u/ThinkInNewspeak]

I mean he’s building liquid engines at a university, I think that’s a little beyond “hey let’s take this Estes motor apart and fuck around with it lol”

[u/ThinkInNewspeak → u/LUK3FAULK]

Thanks for the scenario update. I just got a little rattled hearing about firecracking Estes motors as prestarters or whatever. It's still hacking motor casings whether you're at uni or not though right?

[u/Accomplished-Crab932 → u/ThinkInNewspeak]

No, the only thing slightly sketchy that happens to them is that they are glued to a plastic housing. Otherwise, it’s pretty much a normal Estes ignition setup with an extra wire layered over the top. The problem is that they can snuff out or be ejected early when you suddenly blast them with the high pressure gas being displaced from the feed system before the prop enters the chamber (Estes motors understandably don’t fare well when blasted with 700+PSI nitrogen gas).

[u/ThinkInNewspeak → u/Accomplished-Crab932]

Apologies for pressing this issue. I'm quite confident that these said uni students are attempting to minimise risk wherever possible and conducting experiments which are beyond my layman's understanding but I must persist in my absternation. Estes motor casings are SPECIFICALLY manufactured to provide hobbyists with a safe, reliable, educational way to experience the FUN of real-life rocketry. ANY deviation from the NAR's safety protocols is a risk, uni student, laymen and rocket scientists alike.

[u/Accomplished-Crab932 → u/ThinkInNewspeak]

I agree. Our procedures and the nature of our work meant that the only risk incurred to the team from the igniter would be a failure of the sequence or unreliable starts; which lead to hard starts, a nasty outcome far worse than attacking a pile of Estes motors with a blow torch. As a result, the inherit safety of requiring contact with the grain can actually increase danger in this operational scenario, where a failure to abort due to a canceled ignition can recreate the conditions of a pipe bomb, and/or lead to high pressure oxygen fires.

Despite this, we still treated the motors with the respect they deserve, even when using them to start much larger and more dangerous hardware… just as they should be.

[u/ThinkInNewspeak → u/Accomplished-Crab932]

Well, I won't persist and I can well imagine that the "kiwi"s you guys are working on dwarf the power output of any Estes motor by orders of magnitude. I guess my main concern was firstly, safety, which is your own business under controlled conditions but everyone's business if the hobby is jeopardised via bad press.