On launch day morning, we rose to cloudy skies and temps in the mid 20's, the forecast was still calling for clearing skies, so we proceeded with setting up for the launch. The night before, I had prepped the recovery system, but I ran into one problem. I hadn't taken into account the length of the main recovery system anchor eye bolt. The 10' main chute packs into its deployment bag so tightly, there just wasn't any way to get the main chute past the eye bolt and down to the bulkhead. If was going to fly, I'd have to use a smaller main chute. I ran some simulations using the 4' main from the nose cone, the landing velocity came in at 55 fps. That's pretty fast, and I expected a bent fin or two at that speed. But the fin design on this rocket is particularly well suit to replacing damaged fins. I had an extra 3' chute that I had used for the nose cone deployment tests, so I knew the nose cone could withstand a slightly smaller chute. So I went with 2) 4' chutes on the main body, and the 18" drogue and 3' main on the nose cone.
Set up at the launch site went pretty well. The new launch control trailer saved a lot of time. John is also getting quite adept at setting up the equipment on the launch rail trailer. With Ben's help, John had the trailer set and leveled while I turned on the heater in the launch control shed and set up the electronics. The heated N2O storage box worked well too. With the generator running, the electric heater kept the N2O tank at a nice, comfortable 80 degrees. I was a little worried I'd run out of gas in the generator, I only filled it with about 2 gallons of gas. As it turned out, the generator ran for over 4 hours and didn't run out of gas.
Still photos courtesy Steve Mason and Paul Campbell. Thanks Guys!
Here's the launch control shack ready to see its first use.
John, Ben, Steve and I start setting up the rocket.
Here I'm working on the PIRM2 that releases spring tension to open the N2O valve in the rocket. Things weren't moving as smoothly as I liked. So I added a second spring to make sure the valve opened. Later, I added a third spring for good measure...
Ben, John and I raise the rail.
Here's a look from the pad back at launch control.
Here you see me working on the N2O opening mechanism.
Ben attaches the last support while I search through my fittings box to connect the N2O fill line.
The prep work is just about done now.
Looking from the business end of things up. You can see the tape I use to hold the pre heater grain in the combustion chamber. Above the fins is the N2O fill line with the line cutter attached.
Here's a picture from the field entrance. You can see we had a few people brave the cold weather to watch.
As we approached the opening time slot of our waiver, it became apparent the weather mans promise of mostly clear skies wasn't going to happen. I called the FAA ATC and apprised them of the situation, and asked it we could open the waiver to 15K' first, to fly small rockets, then open the waiver later in the afternoon for the 23K' portion of the waiver. The FAA approved the request, so we proceeded with the launch of some smaller rockets. About 2 hours later, we started seeing some patches of blue sky, and called back in to the FAA to open the waiver for the 23k' window. As it turned out, by the time I got in touch with ATC our blue sky was quickly slipping away to the Northeast, but we had committed to launch at that point.
We turned the generator off on the trailer, I climbed the rail and armed the electronics in both rocket sections, the N2O supply tank was opened and we made our way back to launch control. John was RSO, Ben was my ALCO, Joel was on recovery, Michele performed spectator safety, Steve was on recovery electronics.
I quick check confirmed the telemetry system was working and the remote launch controller reported good continuity on all pyro channels. After a last check of all stations, we were good to start the pre-launch sequence. As soon as I started the fill process the N2O supply pressure dropped to just over 600 psi. As the fill process proceeded, the N2O pressure continued to drop. I decided to stop the fill before I reached 500 psi, regardless of whether the flight tank was full or not. I decided it would be better to fly with more pressure in the flight tank than a full tank with low pressure. At about 5 minutes into the fill, I closed the fill valve and started the launch sequence.
Fill valve closed.
Line cutter activated.
Pre-heater grain ignition.
Countdown- 4,3,2,1 and launch!
Now, let me pause for a moment and reflect on my thoughts. I wasn't really nervous, launching O class hybrids was almost seeming mundane. But prior to the launch I wondered if my luck would catch up to me, and I'd have a launch failure of some sort. There are just so many things that have to go right for the launch to succeed, at some point something is going to go wrong. But it didn't...
The Ganymede engine lit the moment I clicked the launch button and roared off the pad.
The Ganymede moves up the rail on its first flight.
Here's a short video Steve Mason shot. It's a close up of the launch from a tripod near the launch tower.
In this video Paul Campbell shot the launch from LCO area, the longest video including the launch and recovery.
John's video is the best shot of the boost, John was by far the closest to the rocket when it launched.
Here's a short video Michele shot with my camera.
This is a video from inside the launch control shack, from calling the FAA to the rocket landing. Probably boring to most, but shows what goes on at launch control.
A huge thanks goes out to everyone that helped with the launch: John Heithus, Joel Mueller, Michele Gillespie,
Steve Mason, Ben Holmes, Paul Campbell and Scott Frazer. I truly appreciate the help, without which, these launches
couldn't take place.
I watched just long enough to see the Ganymede lift off, then I went to the telemetry computer to watch the data
come in. The rocket quickly passed 13,000' then 14,000', then slowed as it crept towards 15,000'. At just over
14,800' the rocket started its descent. Ben was on the nose cone locating beacon receiver, Steve was on the main
body locating beacon. The main body beacon Steve was tracking was inside the aluminum body, and we wouldn't get
a signal until the drogue chute deployed. As soon as I saw the altitude data indicate the rocket had reached apogee,
I fired the first apogee charge from the telemetry system. Steve and Ben indicated to me they had a signal on main
body beacon, so I knew at that point we had a successful apogee event. I fired the second apogee charge a few moments
later. Since there was no way to know if I set off the first apogee charge or the RRC2X did, I wanted to fire the
second charge just to make sure I knew I had set off at least one of the charges.
I kept an eye on the telemetry as the rocket descended under the drogue chute. At just under 1,000' AGL the people outside sighted both rocket sections under all four chutes. It appeared we had a very nominal flight, with all events working as expected. It didn't take the recovery team long to locate the rocket. As I had hoped, both rocket sections landed close to each other. In fact, the were only about 150 feet apart, much closer than I could have even hoped for.
Here's the landing site of the main body. The 2 lower fins hit hard and were both bent.
Here's the nose cone. I literally "stuck the landing"! The chute is just wrapped around the nose, it didn't go through it as it appears.
All in all, it was a good flight. The low N2O pressure kept the altitude down, but that really wasn't a concern for this flight. All the primary goals were met with flight, and the design changes in this rocket proved fundamentally sound. The RRC2X reported an altitude of over 13,700', while my telemetry system reported apogee at 13,839'. Calculated peak velocity was 919.7 feet per second. The first flight of my new barometric altimeter in the main body worked perfectly as well. I will need to rework the recovery section to allow a larger main chute in the body section. I also need to use better chute protection. The drogue chute on the main body had two large burn through areas from the deployment charge, which also resulted in some tearing of the canopy fabric. Luckily it wasn't enough to alter the descent rate much.
I'll post more data after I pull the engine apart...
Here's a shot of the bulkhead/injector coming out of the combustion chamber.
Here's looking into the nozzle before it was removed. You can clearly see the 2 bent fins.
Here's the fuel grain removed from the case.
The injector/bulkhead is RTV'd to the fuel grain. As you can see here, they must be broken apart.
Here is the nozzle and nozzle retainer. Both are in fine condition, much to Ben's surprise, as he we convinced prior to the launch the retainer would be destroyed...
Fuel Grain: 12.4 lb. start, 10.6 lb. end
Fuel Used: 1.8 pounds
Here's a screen cap of the telemetry data at apogee. Notice the drop in voltage on line 90, that would be the RRC2X firing about 700' below apogee. The 1 in the third column was my upload command to fire the apogee charge, which was already fired anyway... The anomalous 14,800' reading on line 91 was likely suction created by the nose deploying.
Here's a graph of the flight data. The bump at around 30 seconds was a data entry error on my part. The bump at 45 seconds I'm not sure about.
Here's the telemetry file in its native format.
Here's the telemetry file after I formatted it in Excel.
If you look at the telemetry raw data, keep in mind I didn't use the N2O or combustion chamber pressure transducers,
nor did I have the apogee detect wire connected. The only channels transmitting were the altitude and battery voltage.
I'll work this winter on getting more functions working on the rocket end of the telemetry system.
I'm guessing we only had around 32 pounds of N2O in the flight tank, making this an O class flight. Next flight I'll use an extra N2O fill bottle, like I did in the spring flight. I can see now I'll need even more N2O capacity to when I go to fly the Ganymede on the full 80+ pounds of N2O. I see more purchases of N2O bottles in the near future!
I'll need to rework the recovery section to accommodate the full size main chute and repair the 2 bent fins. I continue to learn and gain experience with every new flight. I think I'll fly the Ganymede at least once more to a low(ish) altitude before I configure the rocket for it's full potential.
Oddly enough, on this flight I used 3 separate transmitters, and didn't need a one of them. That's the way it goes sometimes, as soon as you over do the locating end of things, the rocket lands in your lap...