Don't see much value in any kind of build thread other than a Cayemberg-style, stream of consciousness diary/documentary, so here goes, follow along if you wish.
Background:
I've had a run of bad luck recently with getting my projects in the air - after a very encouraging flight of the 4" composite-cased N6000 at Airfest in August, we returned to Texas and immediately upscaled it to a 5" composite case with the same propellant for Balls three weeks later through a seemingly endless series of all-nighters. This was to end in heartbreak on the playa, as we were vertical on the rail and about to arm under clear blue skies, all on the range were told to stand down while the FAA was consulted about the approaching cloud cover; the range never re-opened, so 28 hours home we went. My buddy's Balls project was grounded as well, as our plan had been to fly mine on Saturday and his on Sunday, so our recourse seemed to be to apply for our own waiver in New Mexico in coordination with the TRA White Sands folks. Our target date to have the waiver in hand was Nov. 22, but it became clear that the process would take far longer than this date (still a work in progress). While we waited, I took some of the scrap parts left over from the summer's projects and put together a little 3" min dia thing to fly at a local launch just to bide my time, and said local launch has been cancelled three times and counting. When it rains, it pours.
The waiver application is through June, so once we do get the waiver, it's only right to use it not only to fly the old projects, but to build new projects that we otherwise wouldn't be able to fly anyway save for the annual Black Rock trip (which is usually reserved for one, larger project). While I tend to gravitate towards aluminum fincans for my Black Rock projects, my heart really lies in my ever-ongoing series of no-layup, stock-part fiberglass builds, seeing how far I can stretch cost-effective and readily-available parts that are normally used for basic sport flying (and are well overqualified for that application). For some reason, I find so much more satisfaction in pushing common parts past their intended limits than I do building something highly customized and pimped out. Additionally, while my Black Rock projects tend to be one-offs (which restricts the learning curve pretty heavily), this series of no-layup fiberglass builds has been ongoing for several years running now, so I've enjoyed learning and improving with each round of revisions (and have yet to have an issue with the structural integrity of any of them in flight). A brief run-down of the no-layup rockets/flights so far:
Unnamed 3" project - 6000ns motor - June 2013, Potter, NY
Keep the Change - 4" project - 17500ns motor - July 2013, Argonia, KS
Alpine Style - 3" project - 7600ns motor - July 2014, Argonia, KS
I'll Have Another - named seemed appropriate, and named after the famous racehorse that came within an inch of the Triple Crown in May 2012 (still one of the most exciting Derby wins I've ever seen) - 4" to 3" two-stage - 18000ns to 6000ns motors - ? 2015, Las Cruces, NM
So here's what we've got. I was lucky enough last week to score a 45" length of 4" FWFG tube from my friend Dan, and the original plan was to build rev2 of Keep the Change (single-stage 4"), try and find it after flight this go round, and shoot for 45k. But then 3" FWFG parts came up for sale (thanks, littlemisterbig), and we've got plenty of room left in our potential waiver, so why not try a two stage?
So I have a 45" x 4" airframe, a 36" x 3" airframe, and a 3" nosecone on the way. I went ahead and ordered a 12" x 24" sheet of G10 from McMaster (the usual .125"), as well. Opted to give Rocketpoxy a try this time (all the previous builds have been using Proline 4500, but since Rocketpoxy is 1:1, the pint kit is actually two pints of epoxy for the same price as one pint and change of 4500).
Since most of my stuff is composite-cased these days, I have exactly one 3" and one 4" aluminum case, so I guess we're using those! The 4" is a 58" custom job, but I don't want to use the full 58" of propellant for this one because those loads are a pain to make and require buying two liner/casting sets. So, I'll buy one 48" stick of liner/casting tube, and space the rest with PVC as I've done frequently in the past. The 3" case is a shortened 6000ns case, around 5500ns, which will do fine in the top. Booster fin security isn't a concern at all, because it worked in single-stage configuration on Keep the Change and this one won't be going nearly as fast. The sustainer fins will be the biggest test of this concept to date, as second stages are notorious for having fin flutter issues (right, Jim Jarvis?), but to this end, perhaps it's a blessing in disguise that I lost my 7600ns case in Kansas last July. Oh yeah, and I'll make the propellant super slow as well.
Here are some parameters I've worked out in my head so far:
-Obviously, with a 58" booster motor and a 45" airframe available, it'll be a split-airframe design (no need to sleeve the whole motor anyway). I recently tweaked my go-to fin from the age-old three-fin clipped delta design to mirror the swept-back, four-fin design that all the cool cats are doing these days.
-Transition will be made out of a 4" ogive FWFG nosecone. While I'd love to use a 4" conical, I've heard that the internal coupler overlap is much shorter on these than the 1+ calibers on the ogive ones; with the whole success of the flight quite literally hinging on this joint, I'd rather be safe than sorry.
-While my only other two-stage flight (at Balls 2011) used head-end ignition with the staging electronics in the sustainer's nosecone, I'll probably have the staging electronics in the booster on this one. I want to use my trusty ARTS for staging, and setting one channel to stage and one channel to deploy the booster chute at apogee would seem to make sense.
-Upper stage will likely contain a Stratologger (for backup purposes) and a MARSA54. I recently came into possession of a Multitronix "Kate" unit, and probably won't be able to resist trying to squeeze Kate into the 3" nosecone to hear live how the flight is going, even though it's not the most efficient use of space. This allows me to use Kate for tracking with maybe a cheap old RF backup as opposed to flying my AIM Xtra.
-Will likely be tower-launched from my friend's tower.
-I've got lots more details and ideas in my head, and will be coming back to update this periodically (that's the plan, at least...)
-prophecy
Background:
I've had a run of bad luck recently with getting my projects in the air - after a very encouraging flight of the 4" composite-cased N6000 at Airfest in August, we returned to Texas and immediately upscaled it to a 5" composite case with the same propellant for Balls three weeks later through a seemingly endless series of all-nighters. This was to end in heartbreak on the playa, as we were vertical on the rail and about to arm under clear blue skies, all on the range were told to stand down while the FAA was consulted about the approaching cloud cover; the range never re-opened, so 28 hours home we went. My buddy's Balls project was grounded as well, as our plan had been to fly mine on Saturday and his on Sunday, so our recourse seemed to be to apply for our own waiver in New Mexico in coordination with the TRA White Sands folks. Our target date to have the waiver in hand was Nov. 22, but it became clear that the process would take far longer than this date (still a work in progress). While we waited, I took some of the scrap parts left over from the summer's projects and put together a little 3" min dia thing to fly at a local launch just to bide my time, and said local launch has been cancelled three times and counting. When it rains, it pours.
The waiver application is through June, so once we do get the waiver, it's only right to use it not only to fly the old projects, but to build new projects that we otherwise wouldn't be able to fly anyway save for the annual Black Rock trip (which is usually reserved for one, larger project). While I tend to gravitate towards aluminum fincans for my Black Rock projects, my heart really lies in my ever-ongoing series of no-layup, stock-part fiberglass builds, seeing how far I can stretch cost-effective and readily-available parts that are normally used for basic sport flying (and are well overqualified for that application). For some reason, I find so much more satisfaction in pushing common parts past their intended limits than I do building something highly customized and pimped out. Additionally, while my Black Rock projects tend to be one-offs (which restricts the learning curve pretty heavily), this series of no-layup fiberglass builds has been ongoing for several years running now, so I've enjoyed learning and improving with each round of revisions (and have yet to have an issue with the structural integrity of any of them in flight). A brief run-down of the no-layup rockets/flights so far:
Unnamed 3" project - 6000ns motor - June 2013, Potter, NY
Keep the Change - 4" project - 17500ns motor - July 2013, Argonia, KS
Alpine Style - 3" project - 7600ns motor - July 2014, Argonia, KS
I'll Have Another - named seemed appropriate, and named after the famous racehorse that came within an inch of the Triple Crown in May 2012 (still one of the most exciting Derby wins I've ever seen) - 4" to 3" two-stage - 18000ns to 6000ns motors - ? 2015, Las Cruces, NM
So here's what we've got. I was lucky enough last week to score a 45" length of 4" FWFG tube from my friend Dan, and the original plan was to build rev2 of Keep the Change (single-stage 4"), try and find it after flight this go round, and shoot for 45k. But then 3" FWFG parts came up for sale (thanks, littlemisterbig), and we've got plenty of room left in our potential waiver, so why not try a two stage?
So I have a 45" x 4" airframe, a 36" x 3" airframe, and a 3" nosecone on the way. I went ahead and ordered a 12" x 24" sheet of G10 from McMaster (the usual .125"), as well. Opted to give Rocketpoxy a try this time (all the previous builds have been using Proline 4500, but since Rocketpoxy is 1:1, the pint kit is actually two pints of epoxy for the same price as one pint and change of 4500).
Since most of my stuff is composite-cased these days, I have exactly one 3" and one 4" aluminum case, so I guess we're using those! The 4" is a 58" custom job, but I don't want to use the full 58" of propellant for this one because those loads are a pain to make and require buying two liner/casting sets. So, I'll buy one 48" stick of liner/casting tube, and space the rest with PVC as I've done frequently in the past. The 3" case is a shortened 6000ns case, around 5500ns, which will do fine in the top. Booster fin security isn't a concern at all, because it worked in single-stage configuration on Keep the Change and this one won't be going nearly as fast. The sustainer fins will be the biggest test of this concept to date, as second stages are notorious for having fin flutter issues (right, Jim Jarvis?), but to this end, perhaps it's a blessing in disguise that I lost my 7600ns case in Kansas last July. Oh yeah, and I'll make the propellant super slow as well.
Here are some parameters I've worked out in my head so far:
-Obviously, with a 58" booster motor and a 45" airframe available, it'll be a split-airframe design (no need to sleeve the whole motor anyway). I recently tweaked my go-to fin from the age-old three-fin clipped delta design to mirror the swept-back, four-fin design that all the cool cats are doing these days.
-Transition will be made out of a 4" ogive FWFG nosecone. While I'd love to use a 4" conical, I've heard that the internal coupler overlap is much shorter on these than the 1+ calibers on the ogive ones; with the whole success of the flight quite literally hinging on this joint, I'd rather be safe than sorry.
-While my only other two-stage flight (at Balls 2011) used head-end ignition with the staging electronics in the sustainer's nosecone, I'll probably have the staging electronics in the booster on this one. I want to use my trusty ARTS for staging, and setting one channel to stage and one channel to deploy the booster chute at apogee would seem to make sense.
-Upper stage will likely contain a Stratologger (for backup purposes) and a MARSA54. I recently came into possession of a Multitronix "Kate" unit, and probably won't be able to resist trying to squeeze Kate into the 3" nosecone to hear live how the flight is going, even though it's not the most efficient use of space. This allows me to use Kate for tracking with maybe a cheap old RF backup as opposed to flying my AIM Xtra.
-Will likely be tower-launched from my friend's tower.
-I've got lots more details and ideas in my head, and will be coming back to update this periodically (that's the plan, at least...)
-prophecy
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