Anyone want to work on a 1/4 finished liquid bi-prop rocket motor?

Aerospace / RC
#1

One of my goals for 2023 is to design, build, test, and fly a liquid bi-prop rocket motor. I’m NAR level 3 certified and a member of both DARS and TNT (Tripoli North Texas) which are some local high power rocketry clubs. A friend of mine close with the TNT leadership has said getting permission to use their Seymour TX launch site for testing a liquid biprop motor may not be completely out of the question.

My design is based off the work done by the guys at halfcatrocketry.com, specifically their piston approach to fuel side pressurization. My tank is a 54mm hybrid rocket motor tank from Contrails Rockets and i plan to use a nitrous/methanol+nitro (basically rc engine fuel) oxy/fuel combination which has been proven by halfcatrocketry.com.

My plan is to target the J-K impulse range and fly the engine in a basic 4" (body tube width) airframe. I have the tank, valves, and a quick-disconnect remote fill arm built and on a test stand. Remote fill is handled through a pi zerow running a webapp and some python controlling servos used for fueling and disconnect. All my work so far has involved mostly OTS components from Contrails Rockets and 3d printing. The next test on-deck is a full pressurization test of the tank and valves (this is like “cryo testing” in the real deal rockets). The next major component to be produced is the combustion chamber.

Here’s the rub, I can model and design a combustion chamber but it’s not something you can just buy (or easily 3dprint), it has to be machined. I am not a machinist and want to learn how to use the machine shop but it’s going to take time. The machine shop and other amazing facilities and people of the makerspace is why I’m here. However, time is the one resource I can’t predict, i have a family and very demanding day job my ability to physically get to the makerspace will fluctuates wildly.

many hands make for light work, anyone interested?

3 Likes
#2

Here’s a suggestion. I was listening the other day to the “Houston we have a Podcast” podcast and they were talking about their new RDRE motor that they hotfired last summer at Marshall. Apparently one reason they were able to make it work is because additive manufacturing, especially including the materials, provides the opportunity to design things that are really difficult if not impossible to make using traditional machining/subtractive manufacturing. I know that you are looking for a machinist to partner up on this, but you might want to take a look at the companies that are selling laser sintered 3d prints for your combustion chamber if you can’t find a machinist to help out. Cheers.

2 Likes
#3

Interesting, I originally joined DMS to cut centering rings for a HPR rocket on the small laser we had at the time (2010).

Good luck on your project. I’m sure you have run across Robert Watson. He can tell you about his hybrid motor setup.

1 Like
#4

I’ve looked into metal 3printing and there were some guys i found on youtube that were doing it for a small rocket engine. I tried finding them but could never get a response via the usual channels (email, facebook, etc). The thing about metal 3dprinting is it’s still very expensive (in the thousands of dollars per print last i checked) compared to the time investment of acquiring the skills and machining things yourself. All my designs are optimized for feasibility and not performance so what I need is pretty simple without complex geometries and stuff like that.

When i toured the makerspace the machine shop was just jaw dropping to me so i think i’ll be signing up and taking classes just so i can get it out of my head :slight_smile:

#5

Good luck on your project. I’m sure you have run across Robert Watson. He can tell you about his hybrid motor setup.

as in the Robert Watson?! The guy who runs buyrocketmotors.com and has the handle pyrobob on TRF (therocketryforum.com) ? I would love to meet him, i buy virtually all my HPR motors through his website.

1 Like
#6

Yes that is PyroBob. He used to host a birthday party called the Shindig. Its events are what prompted us to start the Pyrotechnic Artist of Texas (fireants.org). He has a quite serious machine shop too.

2 Likes
#7

This sounds like a fantastic project! I’m interested in learning about rocketry and would like to help out.

I have a couple years’ experience with machining, but I haven’t been with DMS for long and I’m only certified on the Sherline tools so far.

#8

that’s awesome and thanks for replying :slight_smile:

I can only get up there on weekends, do you have any days you’d like to meetup? I can bring my whole rig and we can talk about it and go over everything. I can also bring up an airframe that is about the size i expect to use when ready for a flight. It won’t be the exact same rocket but will be similar.

They guy that gave me the tour of the makerspace said there’s a group working on a hybrid engine that meets up on Sundays at 1 (if i remember right). Maybe we could meetup with them and see what they think too.

(this weekend 8/5-8/6 is my wife’s bday so i can’t make it on those days for sure)

#9

My usual time is Saturday afternoons. I can make Sunday at 1 PM, but I’d have to schedule it ahead of time. Meet up next weekend?

#10

This weekend being the last before school starts is turning out to be a no-go for me. My wife is a HS teacher so i’ll be helping her get her room ready as well as all the misc things to get my two boys ready for their first day. The following weekend may be better.

#11

Works for me. I should be there Saturday 19th afternoon, starting 1 or 2 PM.

If you want to meet Sunday afternoon let me know.

#12

:sigh: this is my problem, i have no predictability on my weekend schedules. I’m sorry for not responding sooner, i need to get time organized before i do anything else.

#13

Lol. We may have more in common than I thought.

Just let me know when you can meet up. Let’s move to DMs so we don’t keep bumping the thread.

#14

I would definitely be interested in helping,
I have experience in CNC/Manual machineing,
As well as electronics/general prototype.

Unfortunately my availability not great until about the start of next month.