Author Topic: HTP/PLA/KMnO4 Hybrid Rocket Engine  (Read 31154 times)

Offline colbourne

  • Full Member
  • ****
  • Posts: 455
  • Liked: 75
  • Likes Given: 51
Re: HTP/PLA/KMnO4 Hybrid Rocket Engine
« Reply #40 on: 06/18/2022 05:24 am »
If the lift off thrust is a bit low, you could use a simple catapult to assist with take off. When ignition has started pull a cord (or use a servo) to release a hold down wire. Use a spring or rubber bungee.
I am avidly following your progress , as I was experimenting with HTP, but in a much more primitive rocket.

Offline Jerry Fisher

  • Member
  • Posts: 97
  • Virginia
    • Fisher Space Systems, LLC
  • Liked: 78
  • Likes Given: 0
Re: HTP/PLA/KMnO4 Hybrid Rocket Engine
« Reply #41 on: 07/04/2022 04:57 pm »
     This is the first launch of the Mark I Viper https://rumble.com/v1b3jsn-mk-i-viper-first-launch.html. The Mk I Viper cleared the rail guide at 2 m/sec and it was under thrust for ~ 7 seconds. I used 50 ml of unstabilized ~ 90% HTP plus 2 ml of ethanol for the oxidizer and PLA infused with KMnO4 for the fuel. Ignition occurred in ~ 0.3 seconds. The mass flow rate was about 13.29 gm/sec resulting in a total propellant mass of ~ 93.0 gm for the 7.0 seconds of thrust.

Quote
use a simple catapult to assist with take off.

    I expected the Mk I viper to clear the rail guide at 4 m/sec. As such, I didn't have the aerodynamic control I needed to correct the trajectory.  I may have to use a catapult but I have a few things to try first. To prevent it from pitching forward, I'll shift the center of mass more in line with the thrust vector. Also, I'll increase the thrust to give me more aerodynamic control. Read all about it in the Jun EOM report.

Offline Jerry Fisher

  • Member
  • Posts: 97
  • Virginia
    • Fisher Space Systems, LLC
  • Liked: 78
  • Likes Given: 0
Re: HTP/PLA/KMnO4 Hybrid Rocket Engine
« Reply #42 on: 08/02/2022 09:10 pm »
   This month I had two flight test and one static test. All three test were an attempt to get a higher thrust. In the flight tests, I increased the throat diameter of the graphite phenolic nozzle to 6.7 mm. The first flight test blew the nozzle and failed to clear the rail guide. The second flight test cleared the rail guide and then blew out the nozzle https://rumble.com/v1eiis1-july-2022-mk-i-viper-flight-test.html. I surmised that hot gases were leaking around the o-ring seal melting the PLA thus weakening the bond between the PLA adapter and CPVC coupling.

   In the static test, I increased the flow rate to ~ 23 ml/sec but keep all other parameters the same. Once again, the nozzle blew out immediately on ignition https://rumble.com/v1ein45-class-i-rocket-engine-static-test-july-19-2022.html. Test results show a pressure spike of ~ 140 psig in the mixing chamber and a peak thrust of ~ 33 N. The high pressure spike in the mixing chamber exceeded the design limit of 100 psia. It appears the thrust is there. I just have to tame it a little. I plan to introduce a variable orifice

Quote
Or printing a flow-restrictor as part of the combustion chamber that rapidly burns away just after ignition.

(ref: edzieba reply #28) at the end of the fuel grain to reduce the initial flow rate thus allowing the mixing chamber time to stabilize.

Offline Jerry Fisher

  • Member
  • Posts: 97
  • Virginia
    • Fisher Space Systems, LLC
  • Liked: 78
  • Likes Given: 0
Re: HTP/PLA/KMnO4 Hybrid Rocket Engine
« Reply #43 on: 09/02/2022 04:40 pm »
   I spent most of the month identifying failure modes such as nozzle blow outs, pinhole leaks, and loose connections. Having resolved the problems, I had a successful test toward the end of the month with a flow rate of ~ 23 ml/sec. The thrust reached a peak of ~ 35 N and then declined ~ 24 N. Overall performance was pretty lousy with the c* and Ceff efficiency at 74% and 66% respectively. However, my O/F ratio was ~7.5, way to high. As such, next month will be spent improving the characteristic velocity and thrust coefficient. Aug 24 test. https://rumble.com/v1idcxo-htppla-test-on-august-24-2022.html

Offline Jerry Fisher

  • Member
  • Posts: 97
  • Virginia
    • Fisher Space Systems, LLC
  • Liked: 78
  • Likes Given: 0
Re: HTP/PLA/KMnO4 Hybrid Rocket Engine
« Reply #44 on: 10/04/2022 02:31 pm »
This month I optimized the expansion ratio of the nozzle to 1.8 in an effort to improve the thrust coefficient efficiency. I had a average thrust of ~ 19 N for about 4.4 seconds https://rumble.com/v1mhl62-htpepla-test-on-09-23-2022.html. However, in my first test, there was no increase in the thrust coefficient efficiency. I plan on keeping the expansion ratio to 1.8 and adjusting the flow rate, fuel core length, and characteristic length. Also, I achieved a 3 to 4 m/sec launch velocity by launching at a 30 degree angle https://rumble.com/v1mhrj8-mk-i-viper-launch-09-20-2022.html

Offline CameronD

  • Senior Member
  • *****
  • Posts: 2374
  • Melbourne, Australia
    • Norton Consultants
  • Liked: 868
  • Likes Given: 548
Re: HTP/PLA/KMnO4 Hybrid Rocket Engine
« Reply #45 on: 10/04/2022 10:09 pm »
Jerry, aside from being focused on engine performance right now, any reason you wouldn't spin-stabilise the rocket (by simply offsetting the fins a little) to at least keep it tracking vertically after leaving the launch rail?? Might be a bit safer, that's all..

As always, keep up the great work!  I knew 'space was hard', but no idea really just how hard!!  :o

« Last Edit: 10/04/2022 10:11 pm by CameronD »
With sufficient thrust, pigs fly just fine - however, this is not necessarily a good idea. It is hard to be sure where they are
going to land, and it could be dangerous sitting under them as they fly overhead.

Offline Jerry Fisher

  • Member
  • Posts: 97
  • Virginia
    • Fisher Space Systems, LLC
  • Liked: 78
  • Likes Given: 0
Re: HTP/PLA/KMnO4 Hybrid Rocket Engine
« Reply #46 on: 10/07/2022 12:43 pm »
Quote
spin-stabilise the rocket

I'll give it a try. Thanks for the suggestion!

Jerry

Offline Jerry Fisher

  • Member
  • Posts: 97
  • Virginia
    • Fisher Space Systems, LLC
  • Liked: 78
  • Likes Given: 0
Re: HTP/PLA/KMnO4 Hybrid Rocket Engine
« Reply #47 on: 11/02/2022 02:33 pm »
   I used some similarity scaling parameters to increase the thrust of the HTPE/PLA hybrid rocket engine. The objective is to increase launch velocity and thus aerodynamic control of the Mk I Viper rocket glider. The three scaling parameters I looked at were initial gas flux, initial surface area flux, and length to diameter ratio. I designed and printed a higher flux fuel grain and inserted a variable PLA flow restrictor at the end of the fuel core. My average thrust went from ~19 N to ~23 N and overall performance was on par with previous test (video link: https://rumble.com/v1r3ico-10262022-plahtpe-hybrid-rocket-engine-test.html).

Offline Jerry Fisher

  • Member
  • Posts: 97
  • Virginia
    • Fisher Space Systems, LLC
  • Liked: 78
  • Likes Given: 0
Re: HTP/PLA/KMnO4 Hybrid Rocket Engine
« Reply #48 on: 12/05/2022 04:25 pm »
I upgraded my rocket engine test stand and ran two tests on the HF fuel core, one of which was on the new test stand. On the second test, I increased the HTPE load to 62.4 ml. Ignition occurred in ~ 0.8 seconds and lasted ~ 5.0 seconds. The thrust was ~ 24 N and the c* efficiency was ~ 91%. Total propellant load was ~ 105 gm. https://rumble.com/v1yzsx4-new-rocket-engine-test-stand.html

Offline Jerry Fisher

  • Member
  • Posts: 97
  • Virginia
    • Fisher Space Systems, LLC
  • Liked: 78
  • Likes Given: 0
Re: HTP/PLA/KMnO4 Hybrid Rocket Engine
« Reply #49 on: 01/03/2023 03:41 pm »
This month I tested a 13.5 cm high flux PLA/KMnO4 fuel core (https://rumble.com/v23pp28-12-13-2022-high-flux-plakmno4-fuel-core-test.html). The objective of this test was to increase the O/F ratio. Ignition occurred in ~ 1.3 sec with ~ 4.2 sec of thrust. From the video, I was able to deduce the mass flow rate. As such, the O/F ratio was ~ 4.0. The L/D was 8.8 and the initial surface flux was ~ 0.24  gm/cm2/sec. From the test, it appears as though the L/D is the dominate parameter as opposed to the initial surface flux.

Offline Jerry Fisher

  • Member
  • Posts: 97
  • Virginia
    • Fisher Space Systems, LLC
  • Liked: 78
  • Likes Given: 0
Re: HTP/PLA/KMnO4 Hybrid Rocket Engine
« Reply #50 on: 02/16/2023 03:35 pm »
   This month, I finally collected all of my data and entered it into a spreadsheet. After two years of scattered data, I saw a trend in the rocket engine testing. Using an oxidizer injector with a 1.5 mm orifice and nozzle throat diameter is 6.0 mm, the rocket engine thrust is  ~ 22 N. Assuming the maximum weight of ~ 15 N for my rocket glider, gives a thrust to weight ratio of 1.5. Over the next several months, I plan to test this design for consistency of time to ignition and thrust.

Offline Jerry Fisher

  • Member
  • Posts: 97
  • Virginia
    • Fisher Space Systems, LLC
  • Liked: 78
  • Likes Given: 0
Re: HTP/PLA/KMnO4 Hybrid Rocket Engine
« Reply #51 on: 03/02/2023 03:09 pm »
This month,  I did three test using the same scaling parameters. Although, the performance results are not as consistent as I'd like, the initial thrust is ~ 20 N at ignition and climbs to ~ 25 N toward the end of the burn. Twenty Newtons at ignition may be enough for aerodynamic control of the rocket glider as it leaves the rail guide. As such, it is my intention to launch the Mk I Viper next month.

Offline Jerry Fisher

  • Member
  • Posts: 97
  • Virginia
    • Fisher Space Systems, LLC
  • Liked: 78
  • Likes Given: 0
Re: HTP/PLA/KMnO4 Hybrid Rocket Engine
« Reply #52 on: 04/13/2023 04:06 pm »
This month,  I worked on the MkI Viper rocket glider. I broke the glider into three sections; a forward section, a mid section, and an aft section. I moved the servos from the mid section to the aft section and connected them directly to the fins. This shifted the center of mass of the rocket glider aft. To compensate, I moved the battery pack to the forward section. Next month, I'll finish the forward and rear cowlings and work on the para-glider.

Offline Jerry Fisher

  • Member
  • Posts: 97
  • Virginia
    • Fisher Space Systems, LLC
  • Liked: 78
  • Likes Given: 0
Re: HTP/PLA/KMnO4 Hybrid Rocket Engine
« Reply #53 on: 05/08/2023 04:16 pm »
This month, I continued my work on the Mk I Viper. The total mass of the Mk I Viper including the propellants is now ~ 1.456 kg which gives me a mass margin of only 44 gm. I attached the paraglider to the fuselage. The wing loading is ~ 0.8 gm/cm2. Next month, I'll tweak the design and hopefully, do some drop testing.

Offline Jerry Fisher

  • Member
  • Posts: 97
  • Virginia
    • Fisher Space Systems, LLC
  • Liked: 78
  • Likes Given: 0
Re: HTP/PLA/KMnO4 Hybrid Rocket Engine
« Reply #54 on: 06/02/2023 01:31 pm »
   This month, I continued working on the drop tower and spent some time on marketing. I decided to use a 15 foot stepladder with an adapter at the top. Also, this month, I attended the National Space Society, 2023 International Space Development Conference in Frisco, Texas. I designed and printed out business cards and transferred the Fisher Space Systems logo and name to several polo shirts. The ISDC was interesting but not the venue for Fisher Space Systems at this time. A future market may exist for corporate spacecraft to reach a space industry for a few days to make the billion dollar decisions and then return home.

Offline Jerry Fisher

  • Member
  • Posts: 97
  • Virginia
    • Fisher Space Systems, LLC
  • Liked: 78
  • Likes Given: 0
Re: HTP/PLA/KMnO4 Hybrid Rocket Engine
« Reply #55 on: 07/07/2023 02:55 pm »
   This month, after several weather delays, I finally got to drop the rocket glider. Unfortunately, the tail section of the glider hit the safety straps, flipped, and crash landed. The impact bent the frame. As such, the rocket glider is no longer usable. That's okay because I've exceeded my mass limit anyway. So, it's back to redesign and a new frame. Also, I have to extend my launch tower adapter so that I don't hit the safety straps next time.

Offline Jerry Fisher

  • Member
  • Posts: 97
  • Virginia
    • Fisher Space Systems, LLC
  • Liked: 78
  • Likes Given: 0
Re: HTP/PLA/KMnO4 Hybrid Rocket Engine
« Reply #56 on: 08/02/2023 04:00 pm »
This month, I used a lightweight generic soda stream bottle as the propellant/pressure tank for the Mk I Viper. The bottle failed the test at 40 psig. However, I found that Soda Stream® has a 500 ml bottle. It's mass is 26 gm lighter than the 1L bottle. Starting at 140 psig in both bottles, the calculated pressure difference is about 8 psig (~123 psig vs ~131 psig) at the end of the run. So, I'll have to test to see the effect on performance.
« Last Edit: 08/02/2023 04:02 pm by Jerry Fisher »

Offline CameronD

  • Senior Member
  • *****
  • Posts: 2374
  • Melbourne, Australia
    • Norton Consultants
  • Liked: 868
  • Likes Given: 548
Re: HTP/PLA/KMnO4 Hybrid Rocket Engine
« Reply #57 on: 08/03/2023 02:55 am »
Keep going, Jerry!  Rocket launch is not meant to be easy.  8)
With sufficient thrust, pigs fly just fine - however, this is not necessarily a good idea. It is hard to be sure where they are
going to land, and it could be dangerous sitting under them as they fly overhead.

Offline Jerry Fisher

  • Member
  • Posts: 97
  • Virginia
    • Fisher Space Systems, LLC
  • Liked: 78
  • Likes Given: 0
Re: HTP/PLA/KMnO4 Hybrid Rocket Engine
« Reply #58 on: 09/06/2023 03:13 pm »
   This month, I repeated the test on February 23rd but used a 500 ml Soda Stream® bottle as the Pressure/Propellant Tank (PPT) versus the 1000 mL PPT. The objective was to test the performance of the rocket engine to see if there was a noticeable difference. All other parameters where the same as the 02/23 test. Time to ignition was 0.4 sec and burn time was 6.0 sec. The average thrust was ~ 22.1 N with a peak of ~ 25.8 N. https://rumble.com/v3f0qhy-htppla-hybrid-test-on-08112023.html I surmise that the short ignition time was due to the fuel core being stored in a dry bag for six months.

   Also, this month, I used the ignition surface flux scaling parameter (0.2 gm/cm2/sec) to designed a new 6-point star fuel core. The 6-point star configuration increased the surface area over the 5-point design. As such, the new fuel core can be made ~ 1.5 cm shorter than the 5-point design. The decrease in fuel core length will result in a mass savings for the overall flight system. Ignition occurred in 0.6 sec and burn time was 5.8 sec. I estimated the thrust based on average chamber pressure and average throat area to be ~ 24.0 N. https://rumble.com/v3f0t3u-htppla-hybrid-test-on-08292023.html The initial test results show a slight increase in performance over the 5-point design.

   Finally, I used an endoscope to take pictures of the PLA/KMnO4 fuel core after a test. The recession of the PLA/KMnO4 fuel core seems to be evenly distributed along the length of the fuel core. This implies that, if designed properly, most of the fuel core can be consumed in the burn.

Offline Jerry Fisher

  • Member
  • Posts: 97
  • Virginia
    • Fisher Space Systems, LLC
  • Liked: 78
  • Likes Given: 0
Re: HTP/PLA/KMnO4 Hybrid Rocket Engine
« Reply #59 on: 10/06/2023 02:55 pm »
  This month,  I ran some test to study the ignition time of the PLA/KMnO4 fuel core after weeks of storage in a dry bag. There were three test, the first was stored in dry bag for ~ 6 months, the second for 24 days, and the third for 31 days. All other parameters were the same. Ignition times varied from 0.4 sec to 0.6 sec. The shorter the ignition time the longer the burn time for a given amount of propellant. The total propellant mass was ~ 115 gm, just under the FAA regulation for a class I rocket.  As such, the procedure is to store PLA/KMnO4 hybrid fuel cores in a dry bag for a minimum of two weeks and as long as four weeks. https://rumble.com/v3n5wbv-ignition-test-for-htpplakmno4-hybrid-fuel-core.html

  Once again, the endoscope shows a nice even burn of the fuel core. The injector evenly distributes the spray around the fuel core. The cone angle of the spray is clearly visible and there is an even burn distribution.

Tags:
 

Advertisement NovaTech
Advertisement Northrop Grumman
Advertisement
Advertisement Margaritaville Beach Resort South Padre Island
Advertisement Brady Kenniston
Advertisement NextSpaceflight
Advertisement Nathan Barker Photography
1