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The Maryland Delaware Rocketry Association’s (MDRA) Red Glare X was awesome, and I got to go on both Saturday and Sunday. The photo above is the smoke trail from Dan Michael’s 3/4 scale Patriot Missile, a 300+ lb rocket that flew on an N2000 and 4 M1315’s. I took 4 photos shortly after burnout and my dad used Photomerge to stitch them together. Here’s a couple more shots of the Patriot, with other projects coming up:
This video captures some of the personalities of rocketry and reasons people go to launches, rather than just shots of rockets flying: (h/t Dick’s Rocket Dungeon) How do you tell the rocketeers from the spectators at a launch? T-shirts. There’s an unspoken code that most rocketry hobbyists wear shirts from past launches — it’s a point of pride that you’ve been to that launch, and it’s a nice way to connect with people (“oh hey, I was at LDRS that year too”). And then there are the funny shirts…
We are so cool. As mentioned before, Steve Eve’s 1:9/1:10 scale Saturn IB was on display at Red Glare IX. Since Steve has already flown and recovered a huge, clustered Saturn V on a similar scale, the biggest difference in this project is the staging. And, because it involves sustainer body panels that flip out (at staging) to act as fins, it’s incredibly complex. So Steve built a 1:3 scale model of his model (which makes it a 1:27 scale model of the real thing) to test the staging and sustainer fin mechanisms. Since I wasn’t flying at Red Glare, I hung around and asked questions and took a bunch of pictures. Because I wasn’t involved in the construction or prep of this project, I apologize for any technical details I get wrong, but I know a lot of rocketry hobbyists are eager to hear about this very cool project. First off, here’s the booster section being prepped:
In the left photo you can see the altimeter or timer bay in one of the 8 smaller tubes that surrounds the booster. In the right you can see a number of things: two of the body panels flipped out as they will be after sustainer separation. The two coupler tubes extended backwards from the sustainer section slip into tubes in the top section of the booster. This interface adds to the small outer diameter tube overlap, and keeps the sections from rotating. In the center hole you can see the Medusa nozzle of the Aerotech J800T motor with igniter installed (but not connected to the electronics). Separation of the stages is accomplished by motor ignition alone — there was no separation charge and the interstage connection is tight enough to prevent drag separation. Below, on the left, is Steve holding one of the airbag components that will trigger either stage separation or (I believe, if I remember correctly) the opening of the sustainer fins. On the right are both sections of the rocket with booster’s K1275R installed.
The booster section also had a forward-facing video camera to capture the staging event. It survived the flight, so it will be interesting to see the footage in future Rockets Magazine videos!
Fitting the two halves together, and sliding it onto the rail:
Because of the complexity of the project it was flown off of one of the away cells, which normally host projects with M and larger motors. Despite the distance, liftoff was fast, impressive, and straight on the Redline K1275:
The boost phase was straight and so was the coast. There was a brief pause between booster K1275 burnout and sustainer J800 ignition, but when the J hit the separation was instantaneous and the sustainer continued upwards, just as straight as during the boost phase of the flight. In this photo, you can see the smoke trail where the J800 burn started, and the booster where it has continued to coast upwards but is trailing behind the sustainer. As you can see, the body panel fins are visibly deployed — the staging mechanism worked!
Normally in rocketry we say the “up part” is the easy part — it’s the “down part” where most of the failures happen. In this case, that might not be true — the up was unusually complex — but the down part’s still where the trouble hit. The booster hit its apogee first, arced over… and came in ballistic. Just as the booster thudded into the ground, the sustainer hit apogee and all eyes turned back to the sky. It arced over and started downwards. The LCO voiced out collective thoughts as we all thought “no! no! eject!” and “what are the chances of two lawn darts in one flight?” But lawn dart it did, alas. I guess you could call the flight a successful failure: the staging mechanism worked, but the test model itself was destroyed. At the end of the day Steve still wasn’t sure what had gone wrong, but neither electric match had fired and they were trying to figure out why. Some photos of the aftermath — it seems to me that both sections were built sturdily and held up fairly well given the circumstances:
Bummer. Finally, a slideshow of all my pictures of the prep, flight, and aftermath: Created with Admarket’s flickrSLiDR. The 1:10 scale (or 1:9 scale, depending on what you’re measuring) Saturn IB projects by Steve Eves and Vern Hoag were on display at Red Glare IX. Rockets Magazine has a page on the projects, but it was quite impressive to see them in person:
Unlike Steve’s Saturn V, which was single stage, the IB will be two stage. Of course, this poses and interesting problem as the Saturn IB has small fins on the first stage and no fins on the upper stage. Steve is solving the problem by having three body panels on the bottom section of the sustainer flip out. They’re spring-loaded so that the don’t flip back in under thrust. Here are three shots of the upper stage fin panels, the first with the fin panel closed, the latter two with it flipped open:
Here are some other views of the Saturn IB on its trailer tower:
And below is a slideshow of all the images I took of both Saturn IB’s, including the primered one that was lying horizontally: 590 = the number of photos I took yesterday when I spent all day at Red Glare IX, arguably the East Coast’s biggest and best fall launch. I borrowed my friend Ashley’s camera (a DSLR) so I got much better photos than normal. With 1st term finals last week at school, I didn’t have time to get many rockets ready for the weekend, so I was in spectator mode only. I’ll post on several specific projects in the next few days — including Jerry O’Sullivan’s Iris, Steve Eves’ 1:9 scale Saturn IB that was on display, and the 1:3 scale model of his big project that he flew to test the staging mechanism. For now, here are some photos of rocketry-themed license plates I spotted at the launch:
I’ve only been to one launch since May, but I have some good excuses. I spent 6 weeks in Guatemala this summer studying Spanish, which meant I missed the MDRA June and July launches. I made it to the August launch with my friend Mark, but all of my rocket stuff was still in storage — I was in the process of moving from Baltimore to DC and left my stuff at my aunt and uncle’s place while I was in Guatemala — so I didn’t fly anything. Then I missed the September launch because it fell the weekend before midterms in the grad program I just started (Masters in global disease epidemiology and control at Johns Hopkins). But Red Glare IX (October 22-24) is looking good, and it’s only 25 days, 18 hrs, and 9 minutes away! Nothing else big is going on, and I don’t have any tests the week after. Plus, the featured projects are looking awesome, with multiple M and N and larger projects slated to fly. One project, a 275 lb. Little John by Rob Bazinet and Todd Harrison, is supposed to have 56,000 Newton-seconds of power — that’s in the P class. That page typically fills out much closer to the launches, so the fact that so many large projects are listed already is a very good sign. I don’t think I can get Lunch Money repaired in time, but am thinking about flying these:
While I’m now a poor grad student (I’m blogging more generally about life and science here), I stocked up on reloads during the last two years, and now have the following motors in stock for the year: Loki I315 Spitfire, CTI H163 White, and Aerotech F40W (White Lightning), G40W, G64W (2), H128W, H180W, H148R (Redline), H123W, H170 Metalstorm, I161W, I284W, I435 Blue Thunder, J420R, and J135W. If I can find the time to get to launches, it should be a good year! I’ll post more about last weekend’s amazing Red Glare VIII soon, but I wanted to start off by writing about . Lunch Money is a 4″ diameter Public Missiles Limited Endeavor kit with a blue and yellow paint job. She has some modifications to a stock build: fiberglassed internal fillets, Aeropack 54mm retainer, no piston, and a (so far unused) electronics bay. So far I’ve flown her on an I218R (LDRS 28), J350W, I161W, Loki I405, and J340M. The last two flights were on Saturday and Sunday of Red Glare. The Loki 38/480 I405 is an awesome motor, and that was my first time flying a Loki motor. 405 Newtons of average thrust is a lot for an I motor, and the flame and effects are great, so it’s definitely a motor I’ll be flying again – especially at $37 retail (the comparably powerful Aerotech I211 is $40 retail, and has a lot less kick).
When Ken at Performance Hobbies said he’d be getting a bunch of H170M, J340M, and K540M reloads in time for Red Glare, I shot him an email right away letting him know I’d like an H and a J. Turns out he only got a small shipment in time for RG8, so I’m glad I ordered mine in advance. I saw several G75M’s and H170M’s fly at Red Glare, but I don’t remember seeing any other J340’s and no K540’s. Motor assembly was normal. Now that the ATF lawsuit is over, propellant slugs are packaged together – in this case, already placed in the liner – instead of in the normal, laughable plastic packaging necessary to have keep the grains packaged ’separately’ for legal purposes. The J340M reload also came with the new 14A delay – max of 14 seconds but adjustable downwards. The same delay adjuster works for CTI, Loki, and Aerotech motors (though you have to be careful to double check which setting is which to get the correct delay length) and I had no problem with assembly. I assembled the motor in identical fashion to how I’ve assembled all my others – and I’ve successfully flown multiple J350’s in this same casing. Don Bryant of D. Bryant Photography was on hand and happened to be standing next to me on the right side of the flight line while I was waiting for the launch, so I asked him to try and get a few liftoff shots. He definitely exceed my expectations, and got a pretty incredible selection of shots in the 2.2 seconds of powered flight. Zero to 391 mph in 2.2 seconds. Here are a few of the highlights:
The boost was perfect – powerful and straight despite the wind. Somewhere between burnout and apogee she slipped into a cloud, so I waiting anxiously to see a chute emerging so that I could track her down. The flight was simmed to go 3,358 feet so I was expecting quite a walk with an apogee deployed chute, with a 42-inch chute to bring her in faster than normal. But there was no ejection charge. When Lunch Money emerged from the cloud, she was coming down in a fast flat spin – and luckily not in a ballistic dive. If the latter had happened, I probably would have gotten the motor casing and fin can back, but that’s about it. Instead, she was spinning rapidly around her central axis, and also rotating horizontally around the center of gravity. I was crossing my fingers hoping that she wouldn’t finally get out of the wind and assume a ballistic trajectory, but luckily that didn’t come to pass. Lunch Money hit hard enough – fin first – to bounce at least 5 feet in the air, maybe more, so I knew there’d be damage. That walk out to the field was a long one. The damage was bad, but it could have been a lot worse. Of the 6 fins, one of the rear ones is toast, and one of the front ones has cracked fillet. There’s also a big crack in the Quantum Tubing where the nose cone goes into the payload bay. The airframe damage is more easily repairable than the fin damage – I’m still not sure how I’ll fix the fins. A shot of the rear fin damage:
Aerotech was on site, so I took the recovered rocket over to them immediately after recovery, and one of their people was very helpful with the motor dissection and failure analysis. The delay grain burned all the way through, and the black powder was still in place in the ejection well, in contact with the burnt-through delay grain. Most of the black powder was loose, but some of it was a bit clumpy, which they said indicates it had grease mixed in with it. Looking at my o-rings, they said I was using way too much grease. Having suffered a blow-by before, I’ve always erred on the side of too much grease rather than too little, and I didn’t know that it could cause a failure. During assembly I didn’t notice any grease in the ejection well, so my best guess is that the extra grease on the o-rings and around the delay element (all within the motor forward closure) moved forward once the motor pressurized, mixing with the black powder enough to prevent its ignition. A user error to be sure, but one that I had never encountered before (or heard of) so frustrating nonetheless. I’ll know to use less grease next time. I’m certainly glad she didn’t lawn dart! While the boost was beautiful, we all know the “down part” is often more difficult than the boost, and now I’ve got to figure out how to repair my flagship. But part of the thrill of rocketry is the risk that it won’t go well, and in this case I think I got off relatively easily. Finally, here’s a slideshow of all of Don Bryant’s Lunch Money shots: Created with Admarket’s flickrSLiDR. There’s an interesting discussion going on at the Rocketry Planet forums in this threat: “Scariest CATO ever, Three Oaks, MI 4/18“. The short version is this: a 6″ diameter, ~60 lb rocket was flown in Michigan on the new Cesaroni N10,000 – the most powerful and brutal commercially-available rocket motor. The motor CATO’d (“catastrophe at take-off” – shorthand for ‘the motor just blew up’) and the 8 lbs of steel ball bearings used as nose weight rained down on the crowd. A good number of them hit people, but ball bearings are small enough that no one was hurt. It certainly sounds scary though. And a good number of the ball bearings cracked windshields, so there was substantial property damage. The discussion is interesting because it explores one of the least pleasant aspects of hobby rocketry. Our hobby has an excellent safety record, in large part because we have rigorous safety codes and self-police our launches to ensure that, for the most part, random idiots don’t ruin it for the rest of us. But even while following those safety procedures, things can go wrong. By all accounts, the flight being discussed was in a very well-constructed rocket build by a world class rocketeer. Yes, the motor is new, and is causing some problems (of the 6 flights I’ve heard of, two CATO’d and one shredded), but it was the unexpected that’s causing a stir: while rocketeers often leave nose weight loose so it’s removable or less likely to come down in one solid, heavy chunk, in this case the loose nose weight compounded the problem by causing damage to a number of cars instead of just one (or none). In the end, no one was injured, and the property damage is being worked out. But incidents like this make me think that some sort of personal injury or worse is inevitable. And there are worse failures, like seeing an 80+ lb N-powered rocket whistle in ballistic at Red Glare 7 last fall, which could have easily killed someone if not for the sheer improbability caused by a big field and people being spread out. In some ways, rocketry is a much safer hobby than many activities that feel much safer. But as more and more people fly rockets, the crowds of spectators get larger, the motors get more powerful, and the rockets get heavier… sooner or later probability will catch up with us in a bad way. While Rocketry Planet Forums and the Rocketry Forums are great places for rocketry information, the chatter is dominated by model- and mid-power rocketeers (nothing against that – I’m just more interested in high power) and high power wannabes (that’s me). On the other hand, the guys at Tripoli Quad Cities have some serious projects on their forums. Here’s a great example: Terry Leright’s Gladys, a minimum diameter N-3180 to N-1100 two-stager. Terry documents the construction, including kevlar and carbon reinforcement on the tubes and fins, the stage coupler (the sustainer motor casing, which has a flush rear closure, extends backwards into the booster airframe). Here’s the interstage coupler:
The finished rocket (actually, he built two of them, but that’s another story):
On the launch pad at Black Rock Desert – I swear I’m gonna make it there someday:
And here’s the liftoff on the N3180 (photo by Ken Adams):
One of the coolest aspects of this flight is that Terry’s electronics – an R-DAS (the same unit I obliterated in my second USLI rocket) – maxed out on its pressure and flatlined the altitude. Terry knew the flight went a lot higher because the R-DAS data showed the rocket was still going 1200 feet per second when the altitude flatlined – that’s over 800 miles per hour. Rocketeer and math whiz David Schultz took a look at the data and calculated that Gladys maxed out at about 70,000 feet. His methods are definitely worth a read! Finally, here’s video of the flight, showing just how massive the acceleration was (Gladys flies around 3:40): (Construction photos by Terry Leright, launch photos by Ken Adams) There are a lot more awesome build threads at the TQC forums. Also recommended: Predator L3, Project Vertigo, and Ultimate Wildman build threads. |
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