4th March 2017, 02:42 PM
4th March 2017, 07:38 PM
I'm wondering what people are doing with GSE. I read a thread discussing hybrid testing for TMT and one issue people mentioned is time at the pad. I never took all that long, connect fill line, connect igniter, continuity test. I'm just curious if there are gains to be had in that area.
Another is fill time. It's not bad for 38/54 but I could see it being more significant the larger you get. Could using servo controlled plug valves work here? It would likely cost less than a similar sized solenoid valve. Larger diameter fill lines?
Assuming some distance from the solid pads, is it dangerous to launch solids while waiting for hybrid fills?
5th March 2017, 12:19 AM
Regarding fill lines and time, your bottleneck is typically the orifice drilled in the CGA-326 or CGA-660 fitting on your bottle. You can't get nitrous out of the tank faster than right there.
6th March 2017, 07:23 AM
I've started what's going to be a long thread on THRP-1 in the Research subforum. I'm putting essentially all the details there, and why I made the choices I made.
7th March 2017, 06:22 AM
How do you get access to the research subforum?
7th March 2017, 08:43 AM
7th March 2017, 09:19 AM
looks like ill have to get a green card first...
13th March 2017, 02:37 AM
Last edited by AlphaHybrids; 13th March 2017 at 06:51 PM.
20th March 2017, 11:50 PM
Another image of a tribrid. This one has a peak thrust of 400 pounds.
21st March 2017, 04:17 AM
That's a great looking shot!
22nd March 2017, 06:38 PM
Looks like it should be a poster... Nice!
22nd March 2017, 07:14 PM
Is your test stand permanent, or do you transport it?
22nd March 2017, 08:13 PM
Gerald - March-ish through October-ish the stand is outside with ~2,000 lbs of bricks for counterweight. It also has stakes to help stabilize it. The winter months it goes to a small shed just to keep it out of the weather. The load cell is kept covered in the summer and removed in the winter.
24th March 2017, 05:36 AM
THRP-1 motor is assembled, ready for static test this Saturday at Battle Park.
24th March 2017, 11:37 AM
That looks awesome! Looking forward to the report.
"He who fights with monsters should look to it that he himself does not become a monster, and if you look long into an abyss, the abyss also looks into you." - Friedrich Nietzsche
"The Future is Not Solid" - Korey Kline
TRA# 08705 L3
26th March 2017, 10:08 PM
I'm not sure the preheater really got going before the fill lines burned through. We had cold flow rather than ignition which dumps the nitrous a lot faster than would have been the case if the combustion chamber was pressurized. Cold nitrous flow is quite a fire extinguisher. Eventually the preheater did light the nitrous and the motor burned nicely then, but most of the nitrous had already been dumped. Everything seemed to work very well except for the delayed ignition. That's a known issue with chilled nitrous systems and probably why there aren't any commercial ones. I'll be making adjustments to the ignition sequence for the next test.
Details will be in the Research forum thread.
My camera batteries were dead at the field so I didn't get any pictures. Others took some shots and at least one video so I should have something to show eventually.
27th March 2017, 04:48 AM
https://www.youtube.com/watch?v=G3JS...ature=youtu.be Video by Nathan, from Battle Park yesterday. Thanks Nathan!
Last edited by G_T; 27th March 2017 at 04:55 AM.
27th March 2017, 04:01 PM
Great work! I did some tests with conical injector designs during the last two years - I used small brass carburetor nozzles from motorcycles. Those are available with a wide range of diameter. Finally I figured out, that due to the conical design the axial velocity component was a little bit to low and caused combustion instabilites. I replaced it with a conventional shower-head design and gained around 10% thrust + a more stable combustion.
Originally Posted by G_T
I will collect some data to present my rocket a bit later.
3rd April 2017, 09:27 AM
Hi Guys, been awhile since I visited the forums, not sure if I ever posted the last test firing I did, 500kg peak 4" hybrid.. (N3000)
using up the NOS, same motor and fuel grain.. quick 1 second blast..
4th April 2017, 05:30 AM
23rd April 2017, 05:16 PM
ROCstock - Hybrids I plan to launch a bunch of Hybrids at ROCstock, June 10'th at Lucerne Dry Lakebed. I will have GSE and gas (if you 'reserve' ahead of time). Anyone interested?
By crossfire in forum National Events
Last Post: 7th April 2017, 03:31 PM
By tab28682 in forum National Events
Last Post: 27th February 2017, 06:03 AM
By GuyNoir in forum Regional or Local Events
Last Post: 15th February 2017, 04:00 PM
By HHaase in forum The Watering Hole
Last Post: 20th December 2016, 02:18 AM
By Jay in forum Low Power Rocketry (LPR)
Last Post: 19th April 2008, 06:48 AM