Author Topic: HTP/PLA/KMnO4 Hybrid Rocket Engine (Read 36770 times)

CameronD · « **Reply #60 on:** 10/09/2023 03:13 am »

Keep up the good work, Jerry! You'll have this thing flying in no time

Jerry Fisher · « **Reply #61 on:** 11/02/2023 01:52 pm »

This month, I ran two tests without the check valve and it didn't blow up https://rumble.com/v3t360t-htppla-hybrid-test-wo-check-valve.html. As expected, there was an increase in both the chamber pressure and the thrust. Ignition time was about 0.3 sec and burn time was about 6.0 sec for each run. The average chamber pressure was ~ 107 psia. The initial thrust was ~ 22 N and increases to ~ 28 N at the end of the run with an average thrust at ~ 25 N. The initial throat diameter for the graphite nozzle was 6.0 mm and eroded to 7.5 mm at the end of the run. So, the next step is to start with a 7.5 mm throat diameter and see if I can get 28 N of thrust at ignition.

Jerry Fisher · « **Reply #62 on:** 12/05/2023 08:10 pm »

This month, in an effort to get maximum thrust with minimum hardware, I ran two tests without the check valve and with a 7.5 mm nozzle throat diameter. The HTPE tank pressure was 140 psig. The first test streamed PLA out the nozzle and the second test blew up https://rumble.com/v3zqn2b-htppla-hybrid-htp-washes-out-ignition.html. Calculations show that the ignition surface flux (ISF) was ~ 0.3 gm/cm2/sec as compared to ~ 0.2 gm/cm2/sec on previous test using the check valve. Last month, the two successful test without the check valve was with the same ISF of ~ 0.3 gm/cm2/sec but with a nozzle throat diameter of 6.0 mm. I surmise that the smaller throat diameter slowed the flow rate enough for ignition to occur while the larger throat diameter did not. After careful consideration, I have decided to add the check valve back into the plumbing.

Jerry Fisher · « **Reply #63 on:** 01/04/2024 03:54 pm »

This month, I had three test with a 7.5 mm nozzle throat diameter. I added the check valve back into the plumbing. Bottom line, it didn't work. I will go back to a 6.0 mm nozzle throat diameter for the Mk I Viper. Also, this month, I added a color analyzer to my diagnostics to help determine the optimum starting concentration for infusion of KMnO4 into the PLA.

Twark_Main · « **Reply #64 on:** 01/04/2024 06:58 pm »

Once again, tremendously valuable real-world experimental data. Lots of people will share their stories of success, but it's just as important (if not more so) to share what didn't work. Thanks again.

Jerry Fisher · « **Reply #65 on:** 02/07/2024 06:51 pm »

This month, I worked on the flight system. I moved the servos and control rods to the vertical and horizontal stabilizers and attached them to the frame. The total mass as of this month is ~ 1056 gm. This leaves 446 gm for the paraglider, canopy, and nosecone.

Jerry Fisher · « **Reply #66 on:** 02/07/2024 06:57 pm »

Quote

.... but it's just as important (if not more so) to share what didn't work.

Thanks. The many failures (lets call them data points) just makes that one success all the sweeter.

Jerry Fisher · « **Reply #67 on:** 03/05/2024 02:53 pm »

This month, I continued work on the flight system. I finished the para-glider, forward strut, equipment bay, and nosecone. I attached the para-glider to the frame to get a feel for the rocket glider, some adjustments are needed. The forward strut is attached to the Soda Stream^® bottle and the equipment bay is attached to the forward strut. The equipment bay houses the receiver, batteries, and switch. I moved this equipment forward to offset the mass of the servos in the vertical and horizontal stabilizers. With the nose cone and propellant, the total mass as of this month is ~ 1190 gm. This leaves 310 gm for the canopy and release mechanism. I just might make it to the 1.5 Kg mass allotment.

Twark_Main · « **Reply #68 on:** 03/05/2024 07:48 pm »

Anyone else getting shades of the Viper from BSG?

https://en.battlestarwiki.org/Viper_(TOS)

sdsds · « **Reply #69 on:** 03/05/2024 08:46 pm »

Quote from: Twark_Main on 03/05/2024 07:48 pm

Anyone else getting shades of the Viper from BSG?

Gotta love those hypersonic inlets, for those times when you really have to dip into a planetary atmosphere.

For @Jerry Fisher, is the plastic bottle for construction/test purposes, or is that part of the flight vehicle structure?

Jerry Fisher · « **Reply #70 on:** 03/07/2024 02:22 pm »

Quote

Gotta love those hypersonic inlets, for those times when you really have to dip into a planetary atmosphere.

Well!!! Before I switched to CO₂ as the pressurant, I was using compressed air. The reason why I switched is because I was still getting burn, duh. I've been doing some research on ramjet engines. It might be possible to come to altitude and speed with a center body main engine and then switch to compressed air using the three hypersonic inlets. It may not be an efficient way of doing things but it sure would be cool looking. Just thinking.

Jerry Fisher · « **Reply #71 on:** 03/07/2024 02:28 pm »

Quote

the plastic bottle for construction/test purposes, or is that part of the flight vehicle structure?

The plastic bottle is part of the flight vehicle structure for the class I engine and may be for the class II engine. There is a lot of volume available for the HTP. You can't store HTP in the plastic bottle, it oxidizes the plastic over a longer periods. But, for immediate launch, it's pretty durable.

Jerry Fisher · « **Reply #72 on:** 04/04/2024 07:12 pm »

This month, I continued work on the flight system. I finished the canopy and release mechanism. The canopy is made of PLA and has four post that fit into spring loaded sockets mounted on the frame. High resistance wire is used as a fuse releasing the canopy when a high current passes through the wire https://rumble.com/v4ngc90-mki-viper-canopy-release.html. The mass of the canopy and release mechanism is ~ 125 gm, less than half of 310 gm mass allotment for the canopy and release mechanism.

Jerry Fisher · « **Reply #73 on:** 05/03/2024 06:41 pm »

This month, I continued work on the flight system. I assembled the entire rocket glider. The final mass is ~1.2 kg. This leaves 300 gm for the HTP oxidizer and PLA/KMnO4 fuel. I performed a dry run for launch. Everything checks out. All systems are go for launch next month.

Jerry Fisher · « **Reply #74 on:** 06/04/2024 02:56 pm »

This is the first launch of the MkI Viper https://rumble.com/v4wzoyh-mki-viper-launch.html. The MkI Viper is powered by a hybrid rocket motor. The oxidizer is ~ 85% hydrogen peroxide (HTP). The fuel is polylactic acid (PLA) infused with potassium permanganate (KmNO4). The total mass of the MkI Viper is ~ 1.4 kg including ~ 150 gm of propellants. As such, the Viper meets the requirements for a class I rocket as defined by 14 CFR 101.22(a). In this video, the propellant load was 50 ml of ~ 80% HTP, 2 ml of Ethanol, and ~ 5 gm of PLA/KMnO4. Total mass of propellant was ~ 78 gm. Flight control is via an RC transmitter and receiver. On this flight, the controls were left in the neutral position to view the take off without guidance. The video shows the Viper yawing to port and pitching down. This can be corrected by rearranging the mass. The objective now is to learn to fly.

Jerry Fisher · « **Reply #75 on:** 07/05/2024 04:37 pm »

This month marked the second launch of the MkI Viper (https://rumble.com/v55ixr6-07032024-mki-viper-launch.html). The liftoff mass was ~ 1.45 kg with a propellant mass of ~ 93 gm. Ignition occurred in less than 0.1 seconds and liftoff occurred in ~ 0.3 seconds. I had active control using a transmitter and receiver. The Viper flipped a few times as it cleared the rail guide. I regained control momentarily. However, burn through at the nozzle inlet caused the Viper to spin out of control and crash into the ground. It was an exciting six seconds.

Jerry Fisher · « **Reply #76 on:** 08/06/2024 07:35 pm »

This month marked the third launch of the MkI Viper https://rumble.com/v59yfnx-mki-viper-aug-1-2024-launch.html. The liftoff mass was ~ 1.4 kg which includes a propellant mass of ~ 94 gm. Ignition occurred in less than one second. I had active control using a transmitter and receiver. The Viper yawed to port and pitched up (as opposed to pitching down on the last launch) as it cleared the rail guide. On comparing the two launches, it is clear that the center-of-mass was below the thrust vector (pitch down) on the last launch and above (pitch up) the thrust vector on this launch. I feel I'm getting a handle on CM calculations with predictable results.

Jerry Fisher · « **Reply #77 on:** 09/04/2024 05:42 pm »

This month I had three launches of the MkI Viper. I replaced the PLA canopy with the fiberglass canopy and calculated the center of mass to be at 3.4 cm with the thrust vector at 3.5 cm. The MkI Viper cleared the rail guide (https://rumble.com/v5dmk50-mki-viper-launch-august-26-2024.html), continued to about 30 feet before pitching up, did a few flips, and landed ~ 15 feet from me.
After careful review of the videos from this month, I surmise that the thrust vector and center of mass are aligned. Also, I believe it has become an issue of air drag. The Viper clears the rail guide and begins to pitch up as it is gaining velocity. I plan on initializing the flaps in the down position to counter the air drag on top.

CameronD · « **Reply #78 on:** 09/05/2024 03:31 am »

Looking good, Jerry! If it's air drag as you say, maybe a little more streamlining is required? Pointy nose cone perhaps?

colbourne · « **Reply #79 on:** 09/05/2024 05:00 am »

Great work Jerry.
Reduce weight, improve aerodynamics (streamlining), and use larger fins.
You could consider going to a powered glider and launching at less of an angle .