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I cannot attend Balls but I will be watching this closely.
Three Quarters of a Hundred Grand with Sunday Silent (75k' Balls Project)
- Thread starter prophecy
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Another day, another evening of doing nothing but rocket work, another update enters the abyss.
Went after work yesterday to have a check-in meeting with the machinist working on the motor parts, seems that it's all humming along nicely. Then, headed home to make some fins.
I started by edging each of the rough-cut blanks to "close enough," before clamping them together to match sand. I love when the plan comes together:
Then we use our CasperTech (TM) fin beveling jig to put a nice, consistent bevel on the fins.
Not bad for a one-footed scrub in an apartment:
All four edged, match sanded, and beveled:
At this point it's about 10:30 and I'm running out of gas, so I went ahead and postponed the tacking (my favorite part of a fincan build) by another day. Today, it should start looking like a rocket.
Two random items of note:
1.) The G10 material I received has a little warp in it - frustrating, but there isn't time to contact the vendor, try and finagle a replacement, and then make new fins once the replacement arrives. I usually buy G10 from McMaster and haven't run into this problem before, but this time paid a mark-up on the item to combine shipping with some items I needed from a hobby vendor. Oh well.
2.) Trying something new here - my usual min dia fin shape had to be tweaked a little bit for this project (shorter root) to fit on the 12" coupler that's serving as the fincan tube. While I was at it, I decided to try something else - I put a little crank in the tip chord (it's canted forward 1/8" as opposed to being parallel with the root chord). At a point, all min dia fin iterations are pretty much the same, but this is a tweak I came up with and wanted to try. In theory, it should reduce frontal drag by a hair.
Not shown: An hour of attempting to clean the mounds of dust out of my apartment (more like swirling it in a nice pattern on the floor). The choice was a dusty apartment or no Balls trip - so it's a concession we're making - but, suffice to say, I hope to not have to do that again.
Stay tuned/prophecy
Went after work yesterday to have a check-in meeting with the machinist working on the motor parts, seems that it's all humming along nicely. Then, headed home to make some fins.
I started by edging each of the rough-cut blanks to "close enough," before clamping them together to match sand. I love when the plan comes together:
Then we use our CasperTech (TM) fin beveling jig to put a nice, consistent bevel on the fins.
Not bad for a one-footed scrub in an apartment:
All four edged, match sanded, and beveled:
At this point it's about 10:30 and I'm running out of gas, so I went ahead and postponed the tacking (my favorite part of a fincan build) by another day. Today, it should start looking like a rocket.
Two random items of note:
1.) The G10 material I received has a little warp in it - frustrating, but there isn't time to contact the vendor, try and finagle a replacement, and then make new fins once the replacement arrives. I usually buy G10 from McMaster and haven't run into this problem before, but this time paid a mark-up on the item to combine shipping with some items I needed from a hobby vendor. Oh well.
2.) Trying something new here - my usual min dia fin shape had to be tweaked a little bit for this project (shorter root) to fit on the 12" coupler that's serving as the fincan tube. While I was at it, I decided to try something else - I put a little crank in the tip chord (it's canted forward 1/8" as opposed to being parallel with the root chord). At a point, all min dia fin iterations are pretty much the same, but this is a tweak I came up with and wanted to try. In theory, it should reduce frontal drag by a hair.
Not shown: An hour of attempting to clean the mounds of dust out of my apartment (more like swirling it in a nice pattern on the floor). The choice was a dusty apartment or no Balls trip - so it's a concession we're making - but, suffice to say, I hope to not have to do that again.
Stay tuned/prophecy
Last edited:
ChrisAttebery
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I'm going to point out the obvious. I'm sure you have your reasons why you haven't already, but you need to pick up a vacuum and attach it to the sander. Ridgid makes some pretty quiet ones now (perfect for the apartment). I picked one up a few years ago for around $100 and it's much quieter than my 20 year old shop vac was.
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You must be single? No spousal equivalent would allow that kinda work in a sole living space unless they were just as addicted to "speed" and altitude as you are.:wink:
Sounds like the foot is o.k. now? Kurt
Sounds like the foot is o.k. now? Kurt
Nick@JET
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I agree, maybe single and a cool neighbor on the floor below you. If you are married then she's a keeper.
Love your determination though. I stay at hotels occasionally and lug all my rocket projects in and out and a lot of people look at you sideways. Maybe the looks you got when bringing your belt sander in your apartment
.
Look forward to the rest of the build
Love your determination though. I stay at hotels occasionally and lug all my rocket projects in and out and a lot of people look at you sideways. Maybe the looks you got when bringing your belt sander in your apartment
.Look forward to the rest of the build
Okay, lots to share. If you haven't noticed by now, the updates will be more of a story than a mechanical "build thread" because these aren't steps being performed in a vacuum, it's real life building an 80k' project on a 2-years-post-college salary, by yourself, in the span of one month, effectively losing your build partner & workspace halfway through. I find it cathartic to record the steps as they occurred, so it is what it is.
Last we left off, we had the machinist humming along, and as my foot was healing, I was building the fincan in my high rise apartment and learning to embrace a coal miner's existence in terms of dust. During a particularly boring FY16 planning meeting on Wednesday, I drew up a tentative build schedule and was horrified to realize I had to work on this every day, 7 days a week, from now until Balls to stand a chance. Wednesday's allotment was tacking all four fins and doing the first set of fillets. I borrowed a guillotine jig to tack on the fins, but the guillotine jig, while clever in design, is built for a more traditional hobby setup with a longer booster airframe as opposed to a fincan. So we need to extend it. Normally, I'd use a motor case, but my oddball-sized motor case is with the machinist, so we need to get creative. The 7-8pm hour, a lot of cursing, a 7600 case, and an entire roll of duct tape solved this problem:
Once I got it all set up, I realized that for whatever reason, the guillotine was way off on the alignment - I've got a pretty good eye for these things and tend not to like having blind faith in equipment. We spent 8-9pm messing with it to no avail, so we went to the leasing office and printed an old-school Estes-style fin guide:
And then did our usual roughing up procedure with the fins:
At this point, it's 10pm, and I'm at that horrible inflection point where you're tired and the night is gone and you've gotten nothing done, and though the right thing is to shelve it and wait for another day, you persevere if only out of frustration. Never a recipe for success. We revisited an old friend of a method for tacking fins - by eye - which, when frustrated at 10:30pm on a Wednesday, was off by about a half a millimeter. Not good enough for an 80k shot, so I snapped the fin off and forced myself to go to bed. Having been consumed by the project every day for most of the last three weeks, I decided I needed to force myself to leave it be until the weekend, my schedule be damned, and attend to the rest of my life.
Last we left off, we had the machinist humming along, and as my foot was healing, I was building the fincan in my high rise apartment and learning to embrace a coal miner's existence in terms of dust. During a particularly boring FY16 planning meeting on Wednesday, I drew up a tentative build schedule and was horrified to realize I had to work on this every day, 7 days a week, from now until Balls to stand a chance. Wednesday's allotment was tacking all four fins and doing the first set of fillets. I borrowed a guillotine jig to tack on the fins, but the guillotine jig, while clever in design, is built for a more traditional hobby setup with a longer booster airframe as opposed to a fincan. So we need to extend it. Normally, I'd use a motor case, but my oddball-sized motor case is with the machinist, so we need to get creative. The 7-8pm hour, a lot of cursing, a 7600 case, and an entire roll of duct tape solved this problem:
Once I got it all set up, I realized that for whatever reason, the guillotine was way off on the alignment - I've got a pretty good eye for these things and tend not to like having blind faith in equipment. We spent 8-9pm messing with it to no avail, so we went to the leasing office and printed an old-school Estes-style fin guide:
And then did our usual roughing up procedure with the fins:
At this point, it's 10pm, and I'm at that horrible inflection point where you're tired and the night is gone and you've gotten nothing done, and though the right thing is to shelve it and wait for another day, you persevere if only out of frustration. Never a recipe for success. We revisited an old friend of a method for tacking fins - by eye - which, when frustrated at 10:30pm on a Wednesday, was off by about a half a millimeter. Not good enough for an 80k shot, so I snapped the fin off and forced myself to go to bed. Having been consumed by the project every day for most of the last three weeks, I decided I needed to force myself to leave it be until the weekend, my schedule be damned, and attend to the rest of my life.
Saturday came bright and early. With lots of potentially fun ways to spend Labor Day weekend - shooting the **** with friends at Airfest, taking a trip to Ohio to play basketball and hang by the lake with an old friend of mine, or going to the beach with my girlfriend, the last thing I wanted to do was go to my post-apocalyptic apartment and spend three days by myself wrestling with this fincan. At this juncture, I think it's appropriate to share a firmly-held belief of mine; many folks would say "it's a hobby, if it isn't fun don't do it." I think there is partial truth to this, but the reality is that for most of my friends it's a profession, and for me, it probably should have been. In climbing, in relationships, in rocketry, certainly in family, anything rewarding and worthwhile has many, many moments where you're stretched to the limit and ask whatever God you believe in why you've put yourself in this situation; that's what makes it rewarding in the end. Doing things only when convenient and only for fun will get you to a certain point; in climbing, that point is most certainly not the Himalayas, and in rocketry, it's most certainly not 80k'. That belief is pretty core to my approach to life, so that's what we're going with. So, all the potential Labor Day weekend plans can go to hell, Saturday morning at 8am I put my phone on airplane mode and head for my apartment.
It's amazing how having energy helps with precision work!
Then it's time to start the tedious process of one fillet set at a time with 12 hours in between. This was my first time working with Cotronics 4525 - I've always used Proline 4500, RocketPoxy, or ProSet - this will be a very important (and unfortunate) fact at 2 junctures in our very near future.
All masked off:
Cotronics is just a little thinner than it's counterparts, but I've long been anti-fillers for a multitude of reasons (most of the above mentioned epoxies come with firm direction not to use any filler), so in my gleeful ignorance I poured the fillets with raw Cotronics. It was an absolute nightmare, and an hour of acetone cleaning drips from everywhere ensued. No time to take pictures of the first set, but on the subsequent three sets I used some chopped carbon which helped things:
While in the fillet cycle, I thought it was a good time to get some odds and ends (nosecone, av bay) done that are normally forgotten until the night before the launch and result in many an "oh, ****" moment.
It's amazing how having energy helps with precision work!
Then it's time to start the tedious process of one fillet set at a time with 12 hours in between. This was my first time working with Cotronics 4525 - I've always used Proline 4500, RocketPoxy, or ProSet - this will be a very important (and unfortunate) fact at 2 junctures in our very near future.
All masked off:
Cotronics is just a little thinner than it's counterparts, but I've long been anti-fillers for a multitude of reasons (most of the above mentioned epoxies come with firm direction not to use any filler), so in my gleeful ignorance I poured the fillets with raw Cotronics. It was an absolute nightmare, and an hour of acetone cleaning drips from everywhere ensued. No time to take pictures of the first set, but on the subsequent three sets I used some chopped carbon which helped things:
While in the fillet cycle, I thought it was a good time to get some odds and ends (nosecone, av bay) done that are normally forgotten until the night before the launch and result in many an "oh, ****" moment.
Doing a non-standard size rocketry project for me comes with cathartic pain points; reminds me of taking ice baths after two-a-day workouts in college. It sucks like none other in the short term; but in the long term it will differentiate you and pay large dividends. In the past, I've shied away from doing a project in a custom size to avoid such inconveniences as the $1500 machinist bill I'm going to have to swallow for all the non-standard parts required; but it's cathartic to think that it was this avoidance and convenience-seeking that has made my flights home from Black Rock "41k', again.....but it was really cool this time! I swear!" so disappointing in the past.
Another challenge with a non-standard size is the nosecone. I was lucky enough to inherit a 1/8" wall, true 4" (4.125" OD) nosecone for free; in my blissful ignorance, I figured I'd cut it off at the 3.75" OD point, the 1/8" wall would match my case, I'd use Rocketry Warehouse 3.5" airframe as a coupler, bada bing.
Wishful thinking. First step is to mark a line as best you can on the radiused surface (I used a 4" coupler (3.75" ID) and slid it over and just eyeballed when it was roughly level, and then traced it). Then we bust out the Dremel. One of my random skills from building large rocketry projects in dorm rooms, frat houses, and high-rise apartments over the years is that I'm sicker than yo average with hand tools, so a potentially tricky step went just fine and we got a square cut on the first try:
The square cut was the pleasant surprise; the unpleasant surprise was that I cut off the bottom 2/3 of the freaking nosecone just to reduce the OD by 3/8". So, my nosecone begins very high up on the radius, and as such the 3.5" coupler goes in just about a quarter of an inch. Awesome.
I sat on the floor and stared at the parts for a second, and came up with an idea. My pin rings for my motor case are made out of 3/16", 3.5" OD, 3.125" ID Aluminum. I ordered a foot and the pin rings only required about 6", so the machinist had a 6" scrap piece. More money, more problems right? A panicked call to the machinist on a Sunday afternoon ensued and he told me to come on over, so I hopped in the car and drove an hour to his place to deliver the nosecone and discuss this solution to an entirely unforeseen problem. Remember when I tried to make a schedule? Yeah, me too.
Nosecone hanging out with motor parts:
My idea was that we'd find the nearest angle to the radiused trajectory (it was 5 degrees) and that he could turn that taper into the 6" piece from the 3.125" ID (a point) out to 3.5" OD. $100 and we had a deal.
I drove an hour home, did the fourth and final set of fillets, and told myself I could go meet some friends at a bar at 10pm if I put in two more good hours on my av bay.
An additional challenge an Aluminum coupler presents is that my normal method of putting electronics in the nosecone coupler is out due to RF transparency issues. So, I did some calculations and figured the taper on the coupler would go 1.75" up into the nosecone. The total piece was 15" long, minus 2.5 for the tip, minus 1.75" for the coupled portion....so I have 10.75" of space 3"-1.25" dia for all my electronics. Awesome. Guess Kate is left out in the cold and we're going with the StratoLogger and Telemetrum only. So I cut a piece 10.75" long 3"-1.25":
This was the same material as the fins...look at that warpage. Seriously, (unnamed vendor?):
A few more odds and ends and we called it a night. Monday was going to be a big day.
Another challenge with a non-standard size is the nosecone. I was lucky enough to inherit a 1/8" wall, true 4" (4.125" OD) nosecone for free; in my blissful ignorance, I figured I'd cut it off at the 3.75" OD point, the 1/8" wall would match my case, I'd use Rocketry Warehouse 3.5" airframe as a coupler, bada bing.
Wishful thinking. First step is to mark a line as best you can on the radiused surface (I used a 4" coupler (3.75" ID) and slid it over and just eyeballed when it was roughly level, and then traced it). Then we bust out the Dremel. One of my random skills from building large rocketry projects in dorm rooms, frat houses, and high-rise apartments over the years is that I'm sicker than yo average with hand tools, so a potentially tricky step went just fine and we got a square cut on the first try:
The square cut was the pleasant surprise; the unpleasant surprise was that I cut off the bottom 2/3 of the freaking nosecone just to reduce the OD by 3/8". So, my nosecone begins very high up on the radius, and as such the 3.5" coupler goes in just about a quarter of an inch. Awesome.
I sat on the floor and stared at the parts for a second, and came up with an idea. My pin rings for my motor case are made out of 3/16", 3.5" OD, 3.125" ID Aluminum. I ordered a foot and the pin rings only required about 6", so the machinist had a 6" scrap piece. More money, more problems right? A panicked call to the machinist on a Sunday afternoon ensued and he told me to come on over, so I hopped in the car and drove an hour to his place to deliver the nosecone and discuss this solution to an entirely unforeseen problem. Remember when I tried to make a schedule? Yeah, me too.
Nosecone hanging out with motor parts:
My idea was that we'd find the nearest angle to the radiused trajectory (it was 5 degrees) and that he could turn that taper into the 6" piece from the 3.125" ID (a point) out to 3.5" OD. $100 and we had a deal.
I drove an hour home, did the fourth and final set of fillets, and told myself I could go meet some friends at a bar at 10pm if I put in two more good hours on my av bay.
An additional challenge an Aluminum coupler presents is that my normal method of putting electronics in the nosecone coupler is out due to RF transparency issues. So, I did some calculations and figured the taper on the coupler would go 1.75" up into the nosecone. The total piece was 15" long, minus 2.5 for the tip, minus 1.75" for the coupled portion....so I have 10.75" of space 3"-1.25" dia for all my electronics. Awesome. Guess Kate is left out in the cold and we're going with the StratoLogger and Telemetrum only. So I cut a piece 10.75" long 3"-1.25":
This was the same material as the fins...look at that warpage. Seriously, (unnamed vendor?):
A few more odds and ends and we called it a night. Monday was going to be a big day.
Monday was supposed to be a huge day. We finally had all our fillets done and cured, so the plan was to sand these in the morning and prep the can for layups, head to the machinist's in the afternoon to help him radially index the pin holes on his mill with the unwieldy 6 foot tube, and head home with all my happy motor parts to lay up the fincan in the evening and leave it under vacuum overnight. A funnier joke has never been told.
Woke up, turned my phone off airplane mode to wait for the call from the machinist, and busted out the 100 grit to smooth out the fillets. Remember when I said it was my first time working with Cotronics?
Yeah.
Sanding steel is easier than sanding this stuff. I ditched the 100 grit in short order for 50 grit, and the little corners of sandpaper were doing a number on the G10 fin and G12 tube, and the Cotronics wasn't budging. My fillets were pretty smooth as is, so it's not like I had a long way to go, but I've quite literally never seen anything like it. Another unforseen problem, why not? Things were going too swimmingly, clearly. Just as I was deciding I needed to purchase some kind of tool to do this, the machinist called me and saved me from myself. In the car, an hour's drive to calm down, off to the machinist's house.
All the finished internals looked awesome. We did some test holes to determine the proper interference fit on the pins, and then took the tube out of the packaging to make a motor case!
Yeah, that's what I was thinking too. This is too easy, let's make it a little more difficult with a nice surprise out of the package that could bury my project:
A massive dent 15" down from one end. A quick calculation determines that if we were to go with it and cut the tube, I'd have just about the same amount of propellant as my friends' project of last year with a heavier fincan. They got 60, so I'd be looking at about 55k' thanks to some staffer at a metalyard after spending my expendable income for the entire year on this project. No thanks. The decision was made to try and get a replacement, but we can't make any progress on that on Labor Day and it certainly isn't the machinist's problem, so it'll have to wait. While I'm up there, I took advantage of his mill to drill, tap, and countersink 6 holes around the circumference of my nosecone coupler. It took a little ingenuity (I think the machinist was queasy with my solution) to mill a radiused part, but after 2 days and roughly $200, Sunday's unforseen problem is solved:
It's now 5pm on Labor Day, and I took a gander to Lowe's out in the suburbs to see what I could do about addressing the fillet sanding issue.
Woke up, turned my phone off airplane mode to wait for the call from the machinist, and busted out the 100 grit to smooth out the fillets. Remember when I said it was my first time working with Cotronics?
Yeah.
Sanding steel is easier than sanding this stuff. I ditched the 100 grit in short order for 50 grit, and the little corners of sandpaper were doing a number on the G10 fin and G12 tube, and the Cotronics wasn't budging. My fillets were pretty smooth as is, so it's not like I had a long way to go, but I've quite literally never seen anything like it. Another unforseen problem, why not? Things were going too swimmingly, clearly. Just as I was deciding I needed to purchase some kind of tool to do this, the machinist called me and saved me from myself. In the car, an hour's drive to calm down, off to the machinist's house.
All the finished internals looked awesome. We did some test holes to determine the proper interference fit on the pins, and then took the tube out of the packaging to make a motor case!
Yeah, that's what I was thinking too. This is too easy, let's make it a little more difficult with a nice surprise out of the package that could bury my project:
A massive dent 15" down from one end. A quick calculation determines that if we were to go with it and cut the tube, I'd have just about the same amount of propellant as my friends' project of last year with a heavier fincan. They got 60, so I'd be looking at about 55k' thanks to some staffer at a metalyard after spending my expendable income for the entire year on this project. No thanks. The decision was made to try and get a replacement, but we can't make any progress on that on Labor Day and it certainly isn't the machinist's problem, so it'll have to wait. While I'm up there, I took advantage of his mill to drill, tap, and countersink 6 holes around the circumference of my nosecone coupler. It took a little ingenuity (I think the machinist was queasy with my solution) to mill a radiused part, but after 2 days and roughly $200, Sunday's unforseen problem is solved:
It's now 5pm on Labor Day, and I took a gander to Lowe's out in the suburbs to see what I could do about addressing the fillet sanding issue.
I ended up purchasing 2" flexible sanding disks designed to chuck into a drill:
Of course, it destroyed the G10 and G12 but didn't touch the Cotronics. I tried a Dremel with a flexible sanding sheet attachment, same outcome. Getting worried about taking too much material off the wrong parts of my fincan, I debated just laying it up as is, but the fillets are massive and draggy. Again, don't settle, don't ever settle, mediocre effort leads to mediocre outcome. And if you're going to be okay with a mediocre outcome, it can certainly be done without mortgaging your financial future.
So, freshly invigorated, back to hand sanding. After ONE HOUR of sanding, I still wasn't done with the first side of the first fillet, everything in my apartment was covered in black dust, and my mind and body were just completely shot, and Labor Day weekend was gone.
Having reached a similar point to tacking the fins last Wednesday, I forcibly removed myself from the situation, turned my phone off and went looking like a coal miner to Buffalo Wild Wings to watch three of the best offensive players in football play in the same backfield at the same time. The schadenfreude at the expense of Virginia Tech's secondary made me feel a little better, and I went to bed.
[video=youtube;wq6ComNZ_Vs]https://www.youtube.com/watch?v=wq6ComNZ_Vs[/video]
First thing this morning, I put in a call to the cheap metals place; I'm fully expecting to get the runaround about getting a replacement. Of course, I have little leverage here; I have thousands of dollars dependent on getting this tube, so between you and me, I'm prepared to pay outright for another one including overnight shipping. We'll see, but I'm really hoping for a lucky break here, Lord knows I need one.
Still don't know what I'm going to do about the fins. At this point, my best thought is to say I'll do one fin (2 sides) per night Monday-Thursday, just ration out the frustration and eat it. Anybody got any brilliant ideas?
Then there's that whole mixing a motor thing, but that's next weekend's issue.
For now, I need to (try to) reinvest myself in my job.
Stay tuned.
-prophecy
Of course, it destroyed the G10 and G12 but didn't touch the Cotronics. I tried a Dremel with a flexible sanding sheet attachment, same outcome. Getting worried about taking too much material off the wrong parts of my fincan, I debated just laying it up as is, but the fillets are massive and draggy. Again, don't settle, don't ever settle, mediocre effort leads to mediocre outcome. And if you're going to be okay with a mediocre outcome, it can certainly be done without mortgaging your financial future.
So, freshly invigorated, back to hand sanding. After ONE HOUR of sanding, I still wasn't done with the first side of the first fillet, everything in my apartment was covered in black dust, and my mind and body were just completely shot, and Labor Day weekend was gone.
Having reached a similar point to tacking the fins last Wednesday, I forcibly removed myself from the situation, turned my phone off and went looking like a coal miner to Buffalo Wild Wings to watch three of the best offensive players in football play in the same backfield at the same time. The schadenfreude at the expense of Virginia Tech's secondary made me feel a little better, and I went to bed.
[video=youtube;wq6ComNZ_Vs]https://www.youtube.com/watch?v=wq6ComNZ_Vs[/video]
First thing this morning, I put in a call to the cheap metals place; I'm fully expecting to get the runaround about getting a replacement. Of course, I have little leverage here; I have thousands of dollars dependent on getting this tube, so between you and me, I'm prepared to pay outright for another one including overnight shipping. We'll see, but I'm really hoping for a lucky break here, Lord knows I need one.
Still don't know what I'm going to do about the fins. At this point, my best thought is to say I'll do one fin (2 sides) per night Monday-Thursday, just ration out the frustration and eat it. Anybody got any brilliant ideas?
Then there's that whole mixing a motor thing, but that's next weekend's issue.
For now, I need to (try to) reinvest myself in my job.
Stay tuned.
-prophecy
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ECayemberg
Well-Known Member
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Hey Steve-O,
Yes, wow! You sir are an animal. As always, enjoying the ever-evolving story that is a Heller-adventure! The trials, tribulations, blood, sweat, improvisation, injured feet, dented hardware, all the highs and lows of next-level rocketry! Thank you so much for sharing...my ambitions are a bit subdued, and elsewhere right now, but they'll come back! When you pour so much effort into such projects, it leaves a person a bit drained after they've come to fruition...I admire your seemingly endless supply of ambition and effort!!!!
Keep up the great work, Steve!:clap:
-Eric-
Yes, wow! You sir are an animal. As always, enjoying the ever-evolving story that is a Heller-adventure! The trials, tribulations, blood, sweat, improvisation, injured feet, dented hardware, all the highs and lows of next-level rocketry! Thank you so much for sharing...my ambitions are a bit subdued, and elsewhere right now, but they'll come back! When you pour so much effort into such projects, it leaves a person a bit drained after they've come to fruition...I admire your seemingly endless supply of ambition and effort!!!!
Keep up the great work, Steve!:clap:
-Eric-
Hey Aidan,
Thanks man - glad you're enjoying it. Do you think you'll be able to make it?
Eric - thanks for the nice note. Had been wondering where you disappeared to - after a few years of pretty intense rocketry activity with young kids, I figured nothing could keep you down! But, haven't heard much from you since my Indiana trip when I first moved down to Texas - we miss ya man. Let me know how you're doing some time and honored to have you following along.
Mark - thanks for your PM. I tried to respond but your inbox is full - shoot me an email at [email protected] when you get a second.
Thanks all,
Steve
Thanks man - glad you're enjoying it. Do you think you'll be able to make it?
Eric - thanks for the nice note. Had been wondering where you disappeared to - after a few years of pretty intense rocketry activity with young kids, I figured nothing could keep you down! But, haven't heard much from you since my Indiana trip when I first moved down to Texas - we miss ya man. Let me know how you're doing some time and honored to have you following along.
Mark - thanks for your PM. I tried to respond but your inbox is full - shoot me an email at [email protected] when you get a second.
Thanks all,
Steve
Kip_Daugirdas
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Holy crap this sounds like me right now! Hope to see it fly in a couple weeks.
watermelonman
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You have a day picked for the flight yet? Sadly I will only make Saturday.
Hey Watermelonman,
Your inbox was full so responding to your PM here:
Hey man,
Yeah, sans tip to tip is something I was playing around with (never had a failure) a few years ago. I put 3" and 4" versions to the high Mach 1/low Mach 2 range without trouble; I tailored the motors to the specific speed range I was comfortable with.
For my last two projects (Aeronaut 3" N and Balls 80k shot) I'm dialing up the motors and the velocity, so I'm throwing some carbon on there. But on a 4g motor you should be absolutely fine without layups provided you do the fillets right.
Videos of 3" and 4" low Mach-2 flights sans layups: [video=youtube;TMR0KMU3cqE]https://www.youtube.com/watch?v=TMR0KMU3cqE[/video]
[video=youtube;6uLLh98e63s]https://www.youtube.com/watch?v=6uLLh98e63s[/video]
BTW, I'm shooting for first thing Saturday morning for my Balls flight. Don't want to rush it for Friday. You going to be able to join our group for dinner again?
Best,
Steve
Your inbox was full so responding to your PM here:
watermelonman said:
Hey man,
Yeah, sans tip to tip is something I was playing around with (never had a failure) a few years ago. I put 3" and 4" versions to the high Mach 1/low Mach 2 range without trouble; I tailored the motors to the specific speed range I was comfortable with.
For my last two projects (Aeronaut 3" N and Balls 80k shot) I'm dialing up the motors and the velocity, so I'm throwing some carbon on there. But on a 4g motor you should be absolutely fine without layups provided you do the fillets right.
Videos of 3" and 4" low Mach-2 flights sans layups: [video=youtube;TMR0KMU3cqE]https://www.youtube.com/watch?v=TMR0KMU3cqE[/video]
[video=youtube;6uLLh98e63s]https://www.youtube.com/watch?v=6uLLh98e63s[/video]
BTW, I'm shooting for first thing Saturday morning for my Balls flight. Don't want to rush it for Friday. You going to be able to join our group for dinner again?
Best,
Steve
Last edited:
Binder Design
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Sorry to see this. We talked about some of these issues. Tubing gets mistreated and bent. Sometimes it is wrong right from the extruder. I recently got one with an extrusion defect so bad that a customer's liner would only go halfway in. Another recent order they sent me pipe instead of tubing. I've had tubes extruded from SAPA that were scored so bad on the ID from a worn out extrusion die that there was no way you could get an O ring to seal. Tubes with a different ID from end to end are a lot of fun too.
Good luck with your second tube. Maybe you should order a couple of them. I always order about double what I need just in case.
I forced myself to take Tuesday night off to go to the gym for the first time in two weeks and attend to the rest of my life.
Plan was to hit the ground running Wednesday night on the sanding. I got home at 5:45 and didn't want to do precision work tired from the work day, so I closed my eyes for "half an hour" and the next thing I knew it was 6am. My body has had it with this project, I guess.
So, last night was the night. 4 hours of sanding 7-11, one hour per fillet, and we have 4 out of 8 done. I reached a convenient stopping point when my fingers started to bleed (even though I was wearing gloves to extend the time it took for my fingers to get worn through the skin), acetone got in the cuts and I decided my state was no longer conducive to precision work.
A note about these fillets; over the years, I've gotten pretty good at shaping fillets with epoxies designed to be shaped (ProSet and the like). All it takes is a little smoothing with 180 grit and the fins melt into the body tube. ProSet, 4500, RocketPoxy etc are plenty strong enough for most anything (Verrukt even used RocketPoxy), but we were going for raw strength here. After the disaster with the first set of fillets using unthickened epoxy, I switched to something that looked like a hairball mixed with tar and was impossible to shape. I did the best I could by putting peel ply over it and pressing a 54mm tube down over the peel ply, but peel ply can wrinkle slightly when wetted out, etc. and so on. Point being, even after sanding until my fingers bled, these are probably the worst looking fillets I've had in years, but they're also the strongest. The divots will serve as nice surface prep for the layup and we should be all set.
Notice the circular machine marks on the righthand fillet pictured; this was the guinea pig fillet with all the various tools I bought that ultimately failed to be effective. Again, it'll serve as good surface prep.
The scabs on my fingers will need a few days to heal; good thing I've arranged with my friend to use his garage tonight and tomorrow night to get the two mixes on the motor done, so by Sunday, I should be good to go.
This is going to come down to the 11th hour, as per usual.
-prophecy
Plan was to hit the ground running Wednesday night on the sanding. I got home at 5:45 and didn't want to do precision work tired from the work day, so I closed my eyes for "half an hour" and the next thing I knew it was 6am. My body has had it with this project, I guess.
So, last night was the night. 4 hours of sanding 7-11, one hour per fillet, and we have 4 out of 8 done. I reached a convenient stopping point when my fingers started to bleed (even though I was wearing gloves to extend the time it took for my fingers to get worn through the skin), acetone got in the cuts and I decided my state was no longer conducive to precision work.
A note about these fillets; over the years, I've gotten pretty good at shaping fillets with epoxies designed to be shaped (ProSet and the like). All it takes is a little smoothing with 180 grit and the fins melt into the body tube. ProSet, 4500, RocketPoxy etc are plenty strong enough for most anything (Verrukt even used RocketPoxy), but we were going for raw strength here. After the disaster with the first set of fillets using unthickened epoxy, I switched to something that looked like a hairball mixed with tar and was impossible to shape. I did the best I could by putting peel ply over it and pressing a 54mm tube down over the peel ply, but peel ply can wrinkle slightly when wetted out, etc. and so on. Point being, even after sanding until my fingers bled, these are probably the worst looking fillets I've had in years, but they're also the strongest. The divots will serve as nice surface prep for the layup and we should be all set.
Notice the circular machine marks on the righthand fillet pictured; this was the guinea pig fillet with all the various tools I bought that ultimately failed to be effective. Again, it'll serve as good surface prep.
The scabs on my fingers will need a few days to heal; good thing I've arranged with my friend to use his garage tonight and tomorrow night to get the two mixes on the motor done, so by Sunday, I should be good to go.
This is going to come down to the 11th hour, as per usual.
-prophecy
Looks pretty good to me since you're going to do a layup over it. One thing about Cotronics 4525B or 4525IP is one can hit it with a heat gun early on in the curing process and get it to liquefy again.
The fillets I did with it, I leveled out the rocket and pulled the masking tape after 20 or 30 minutes and gently heated the fillets and it will reflow and soak into the substrate better.
4500 will also behave in a like manner. Kurt
The fillets I did with it, I leveled out the rocket and pulled the masking tape after 20 or 30 minutes and gently heated the fillets and it will reflow and soak into the substrate better.
4500 will also behave in a like manner. Kurt
JimJarvis50
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Wilson: Thanks man, much appreciated. The one piece missing as of yet is a launch control system. Any chance I could use your system at 7am Saturday morning? I was going to buy a wireless system designed for fireworks off of Amazon but ever since I had an M go off in my face in 2006 as I was installing the igniter thanks to a faulty wireless system, I'm a little wary, especially buying a cheap one.
As far as the tower, as Jim alluded to, I think Manny and I have it covered - rail buttons are a cardinal sin given the mantra of this project, so Manny put something together and delivered it to Jim at Airfest last week.
None of my other friends are bringing anything to fly, so after I fly I'll hopefully have most of two days to help you get your plethora of projects in the air!
Jim: Thanks for letting me know, and thanks again for making the travel part of the equation a non-stressor. I'll see you in exactly a week, almost to the hour (that's terrifying).
Ryan: Thanks man! As I mentioned via PM, I heard a rumor you may be Black Rock bound - would be cool to see you out there. Regardless, I'll let you know if anything comes up (planning to lay up my fincan on Wednesday).
General update - on the computer getting my batch sheet ready for mix #1 this afternoon. Mix 2 tomorrow, mill the pin holes with the machinist on Monday, finish sanding Tuesday, lay up Wednesday, ablative Thursday, motor assembly Friday, up to Austin to deliver to Jim first thing Saturday morning.
Gulp.
-prophecy
As far as the tower, as Jim alluded to, I think Manny and I have it covered - rail buttons are a cardinal sin given the mantra of this project, so Manny put something together and delivered it to Jim at Airfest last week.
None of my other friends are bringing anything to fly, so after I fly I'll hopefully have most of two days to help you get your plethora of projects in the air!
Jim: Thanks for letting me know, and thanks again for making the travel part of the equation a non-stressor. I'll see you in exactly a week, almost to the hour (that's terrifying).
Ryan: Thanks man! As I mentioned via PM, I heard a rumor you may be Black Rock bound - would be cool to see you out there. Regardless, I'll let you know if anything comes up (planning to lay up my fincan on Wednesday).
General update - on the computer getting my batch sheet ready for mix #1 this afternoon. Mix 2 tomorrow, mill the pin holes with the machinist on Monday, finish sanding Tuesday, lay up Wednesday, ablative Thursday, motor assembly Friday, up to Austin to deliver to Jim first thing Saturday morning.
Gulp.
-prophecy
AlnessW
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No problem Steve, I owe it to you for all of your help this past year. As you may have heard, I just picked up (ironically) a Wilson F/X wireless system, so thankfully no coiling and uncoiling of wire reels this year. It also won't light an igniter in your face! The whole system takes about 5 minutes to set up - happy to loan it to you for early Saturday morning. Definitely, don't buy a cheap fireworks launcher... Again, not wanting to make the same mistakes as last year, I am tentatively planning on flying my N on Saturday as well, say 8:00 AM?
By the way, was wondering if you'll be at the launch on Friday? I may fly some of my "plethora" then - rockets will be ready, just never can be sure about mother nature. I could definitely use your help.
Sounds like you/Jim/Manny are well-covered with transportation and a pad. I figured you'd want to avoid rail buttons anyways...
By the way, was wondering if you'll be at the launch on Friday? I may fly some of my "plethora" then - rockets will be ready, just never can be sure about mother nature. I could definitely use your help.
Sounds like you/Jim/Manny are well-covered with transportation and a pad. I figured you'd want to avoid rail buttons anyways...
Thanks Wilson. Yeah, I'll be there Friday - I have that designated as my prep/assembly/tower/etc. day, basically greasing the wheels for everything to go smoothly first thing Saturday morning (as opposed to what I used to fall victim to at launches - "weather's pretty good right now...how far away am I? Four hours? Could I make it 3? Hurry! They're talking about closing the waiver an hour early since nobody's flying! Someone go run up and talk to them!" kind of thing. Maybe we fly your N on Friday? Either way, glad to help.
UPDATE
Another weekend, another two and a half days of interacting with nobody, barely sleeping or eating, and still somehow not getting enough done on the project. I drop my stuff off with Jim in 5 days. But, when I left work on Friday, I had yet to mix any portion of the motor, and the motor is now entirely mixed (but not done - I've got about five hours left of grain prep/coring/assembly). No pictures this time, since I apparently got "warned" by a forum admin about breaking forum rules by discussing chemistry as it applies to rocketry in another thread last week. Not sure how this makes sense given that it's a hobby entirely predicated on chemistry, but oh well. Not like I'd care to post my formula anyway...
Friday night
Friday night was spent moving my mixing equipment (12qt Hobart weighs about 200lb), vacuum, chems, etc. from A5tro An0n's house, where they've lived for most of the past two years, to my friend's garage for the weekend. This was a pretty bummer of a way to spend an evening; in the short term, hobbling heavy equipment around greater Houston on one foot on a Friday night; but also (and especially) in the long term. Rocketry, for me, has always been as much about the journey (as may be evident in this thread) as it is about the technical applications; the people are a big part of that journey. I grew up with a close knit group of rocket people on the East coast, and since moving to Texas and knowing nobody, A5tro An0n and I have put together some pretty badass projects. We're the same age, with similar perspectives, life circumstances, and rocketry goals - but the show must go on. Anyhow, Friday night sucked both in the short term and the long term, but we got it done around midnight.
Saturday
Saturday was mix #1, 6500g of a high-solids, highly-aluminized propellant for the top grains. I always find that with mixing, equipment maintenance can always wait "till next time," but I didn't want to mix this motor like that, so I spent three hours deep cleaning my mixer, replacing the battery on my scale, changing the oil on my vacuum, etc. We finally got mixing around 3pm and finished at 11:11pm - 8hr, 11min, not too bad. I usually range between 6-12 hours depending on how I'm processing the propellant, etc.
Sunday
Saturday was so much fun that I just had to wake up again the next day and do it all over. Started at 1, hoping to finish at 9 or so instead of 11, but ran into one of those stupid things that ends up chewing up the hours like none other. I got to the bottom of my bucket of 90, and it was a BRICK - not a typical 90 sieve-it-and-you're-ok brick, a BRICK. (4) hours later, I had it sieved and we kept going. This batch was for the nozzle grains, so I tweaked the formula slightly to counteract the inherent erosivity of a long motor. Finished at 11:30, went home, and realized that my liners weren't square as received - and since we're splicing a two-piece liner here, a square joint is crucial, especially with such a hot propellant. But we've only got hand tools, so we channel our inner James Grover and git r dun while still giddy from the fumes from cleaning the mixing equipment:
23 hours of a 36 hour period spent mixing - I'm nearing the end of my rope with this thing, but the good news is that regardless of how complete the rocket is, we're done in 5 days. So, we're on the home stretch.
I've got the replacement 6' tube in my car in the parking lot at work today (luckily, it's dent-free) - headed to the machinist's directly from work to radially index the holes for the pin rings.
It's not the size of the dog in the fight but the size of the fight in the dog-
prophecy
UPDATE
Another weekend, another two and a half days of interacting with nobody, barely sleeping or eating, and still somehow not getting enough done on the project. I drop my stuff off with Jim in 5 days. But, when I left work on Friday, I had yet to mix any portion of the motor, and the motor is now entirely mixed (but not done - I've got about five hours left of grain prep/coring/assembly). No pictures this time, since I apparently got "warned" by a forum admin about breaking forum rules by discussing chemistry as it applies to rocketry in another thread last week. Not sure how this makes sense given that it's a hobby entirely predicated on chemistry, but oh well. Not like I'd care to post my formula anyway...
Friday night
Friday night was spent moving my mixing equipment (12qt Hobart weighs about 200lb), vacuum, chems, etc. from A5tro An0n's house, where they've lived for most of the past two years, to my friend's garage for the weekend. This was a pretty bummer of a way to spend an evening; in the short term, hobbling heavy equipment around greater Houston on one foot on a Friday night; but also (and especially) in the long term. Rocketry, for me, has always been as much about the journey (as may be evident in this thread) as it is about the technical applications; the people are a big part of that journey. I grew up with a close knit group of rocket people on the East coast, and since moving to Texas and knowing nobody, A5tro An0n and I have put together some pretty badass projects. We're the same age, with similar perspectives, life circumstances, and rocketry goals - but the show must go on. Anyhow, Friday night sucked both in the short term and the long term, but we got it done around midnight.
Saturday
Saturday was mix #1, 6500g of a high-solids, highly-aluminized propellant for the top grains. I always find that with mixing, equipment maintenance can always wait "till next time," but I didn't want to mix this motor like that, so I spent three hours deep cleaning my mixer, replacing the battery on my scale, changing the oil on my vacuum, etc. We finally got mixing around 3pm and finished at 11:11pm - 8hr, 11min, not too bad. I usually range between 6-12 hours depending on how I'm processing the propellant, etc.
Sunday
Saturday was so much fun that I just had to wake up again the next day and do it all over. Started at 1, hoping to finish at 9 or so instead of 11, but ran into one of those stupid things that ends up chewing up the hours like none other. I got to the bottom of my bucket of 90, and it was a BRICK - not a typical 90 sieve-it-and-you're-ok brick, a BRICK. (4) hours later, I had it sieved and we kept going. This batch was for the nozzle grains, so I tweaked the formula slightly to counteract the inherent erosivity of a long motor. Finished at 11:30, went home, and realized that my liners weren't square as received - and since we're splicing a two-piece liner here, a square joint is crucial, especially with such a hot propellant. But we've only got hand tools, so we channel our inner James Grover and git r dun while still giddy from the fumes from cleaning the mixing equipment:
23 hours of a 36 hour period spent mixing - I'm nearing the end of my rope with this thing, but the good news is that regardless of how complete the rocket is, we're done in 5 days. So, we're on the home stretch.
I've got the replacement 6' tube in my car in the parking lot at work today (luckily, it's dent-free) - headed to the machinist's directly from work to radially index the holes for the pin rings.
It's not the size of the dog in the fight but the size of the fight in the dog-
prophecy
AlnessW
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Sounds like a plan! Definitely, wouldn't want to miss a weather window due to lack of ready-ness. Totally game for flying my N on Friday, in fact that may be a better plan. We'll see what happens...
Looks like you're getting close - can't wait to see this thing fly!
Looks like you're getting close - can't wait to see this thing fly!
Another day another update
Headed after work yesterday with my motor case riding shotgun to the machinist's house. We faced the new tube on the mill and then radially indexed, match drilled, and reamed the nozzle pin holes:
While I was up there, I brought my nosecone and we indexed and match drilled (4) #46 (.081") holes for press fit on #2 nylon shear pins. Typical hobby flights using a looser fit with maybe some electrical tape over the pin head work fine, but last time a friend of mine tried that method on a non-hobby flight, the heads melted off, the pins fell out of the looser holes, the oversized main dumped at 60k' and it was never recovered.
In between two of the shear pin holes, we drilled a 5/32" combination pressure bleed/altimeter vent hole. Since the coupler is aluminum, all the electronics need to be stuffed into the tip of the nosecone, but the baro-based PerfectFlite unit requires a vent hole to not be drilled on a taper, so we'll open the standard 1/8" pressure bleed hole to 5/32" to serve double duty, and then drill a second 5/32" hole in the bulkplate between the aluminum coupler and fiberglass portion where the electronics are to allow the pressure to equalize calmly.
The grains need to be trimmed to length and the liner cut to length to match and squared on the mill in order to determine the precise location of the upper pin ring. So, we paused while I ran to Wal-Mart out in the burbs to buy a quarter-sheet sander to face the grains to length for $13.88, and got going about 10:30. Finally got to bed at 2:37am...
Note the differential grain lengths; this is another tactic I employ along with tweaking the formula to counteract erosive burning.
Tonight, we'll core the grains, cut the liner to length and face it up on the mill, and drill the upper pin ring.
Time to double up on the coffee at work
Headed after work yesterday with my motor case riding shotgun to the machinist's house. We faced the new tube on the mill and then radially indexed, match drilled, and reamed the nozzle pin holes:
While I was up there, I brought my nosecone and we indexed and match drilled (4) #46 (.081") holes for press fit on #2 nylon shear pins. Typical hobby flights using a looser fit with maybe some electrical tape over the pin head work fine, but last time a friend of mine tried that method on a non-hobby flight, the heads melted off, the pins fell out of the looser holes, the oversized main dumped at 60k' and it was never recovered.
In between two of the shear pin holes, we drilled a 5/32" combination pressure bleed/altimeter vent hole. Since the coupler is aluminum, all the electronics need to be stuffed into the tip of the nosecone, but the baro-based PerfectFlite unit requires a vent hole to not be drilled on a taper, so we'll open the standard 1/8" pressure bleed hole to 5/32" to serve double duty, and then drill a second 5/32" hole in the bulkplate between the aluminum coupler and fiberglass portion where the electronics are to allow the pressure to equalize calmly.
The grains need to be trimmed to length and the liner cut to length to match and squared on the mill in order to determine the precise location of the upper pin ring. So, we paused while I ran to Wal-Mart out in the burbs to buy a quarter-sheet sander to face the grains to length for $13.88, and got going about 10:30. Finally got to bed at 2:37am...
Note the differential grain lengths; this is another tactic I employ along with tweaking the formula to counteract erosive burning.
Tonight, we'll core the grains, cut the liner to length and face it up on the mill, and drill the upper pin ring.
Time to double up on the coffee at work
Last edited:
Total sleep count since last update: 6 hours
Not nearly as bad as the Aeronaut totals, so I'm improving!
Tuesday
Headed after work, again, to the machinist's. In order to drill the upper pin ring in the proper place, I needed the final liner length. In order to get the proper final liner length (to the thousandth of an inch), I needed to know the final propellant length. So after coring and a final face sanding:
This was before I cut the liner to final length. A note here; normally it's good practice when splicing a two piece liner together that the joint be at the forward end, because especially on a motor with such an inherently erosive geometry, the nozzle grains will burn out well before the top grains. Since Scott at Loki was kind enough to sell me a partial piece of phenolic liner on top of the 48" stick I bought for a nominal fee as opposed to me having to buy two full sticks, I was kinda captive to the length that was available. In order to put the joint at the top, the piece wasn't long enough to have the splice in the middle of grain 4, and the 48" stick wasn't long enough to make it to the middle of grain 5, so I've got no choice but to put the joint on the nozzle end. The silver lining is that due to my geometry, the nozzle grain is far and away the longest, so I've got a nice 6.5" of grain coupler on each end. I've taken several measures to tame the erosivity of the motor (grain lengths and differing formulas in the top and bottom), so the grains should burn out pretty close to at the same time. I'll put some RTV on there when I load the motor just because I'm paranoid, and we're marching on.
Bottom pin ring looking sexy as we mill the top one:
The completion of the upper pin ring marked the conclusion of the machinist's involvement, a moment I had been dreading. I swallowed hard, cut a check for over half the value of my checking account total, packed up my car, and left.
"This is why I've been flying standard thick-wall hobby cases all these years and why my outcomes have been so limited...because I didn't want to do this."
On the way home, the gluttony, the exhaustion, the whole lot of it got to me so I had to pull over and just think on it for a while. I thought about the merits of passion and dedication, my obsessive personality, when dedication becomes ignorance and selfishness, and all those close to me that I've alienated (some beyond repair) over the years in my pursuits that make sense to few. Yep, we've had these moments before! Like, last month for Aeronaut, waking up at 4am for practices in college, and every mountain I've climbed. Welcome to TNDO (take no days off) week people - an annual (in this case biannual) tradition!
This guy came to speak at UNC a couple of times, and I used to listen to this stuff on repeat during low moments in college. Gets me going every time, and Lord knows I need it this week:
[video=youtube;x0a7Hi51b3s]https://www.youtube.com/watch?v=x0a7Hi51b3s[/video]
Wednesday
I can barely remember what happened during the day on Wednesday...about mid-way through TNDO weeks I'll start chugging EmergenC to avoid getting sick for the launch due to lack of sleep. I'm really, really looking forward to fully investing myself in my month-old job when I get back from Black Rock.
After work, I headed to Rice University to meet up with Random Flying Object, who makes satellite electronics for a living. Can't imagine a better guy to modify my Telemetrum. Left Rice at about 8:30, got home at 9...time to go to battle again with the Cotronics. We last touched base on the fillet sanding last Thursday; though I'm now feeling very behind on my fincan, since last Thursday, we've mixed an O motor from start to finish, and machined a hardware set from start to finish. Pretty cool. Man your battle stations:
Not nearly as bad as the Aeronaut totals, so I'm improving!
Tuesday
Headed after work, again, to the machinist's. In order to drill the upper pin ring in the proper place, I needed the final liner length. In order to get the proper final liner length (to the thousandth of an inch), I needed to know the final propellant length. So after coring and a final face sanding:
This was before I cut the liner to final length. A note here; normally it's good practice when splicing a two piece liner together that the joint be at the forward end, because especially on a motor with such an inherently erosive geometry, the nozzle grains will burn out well before the top grains. Since Scott at Loki was kind enough to sell me a partial piece of phenolic liner on top of the 48" stick I bought for a nominal fee as opposed to me having to buy two full sticks, I was kinda captive to the length that was available. In order to put the joint at the top, the piece wasn't long enough to have the splice in the middle of grain 4, and the 48" stick wasn't long enough to make it to the middle of grain 5, so I've got no choice but to put the joint on the nozzle end. The silver lining is that due to my geometry, the nozzle grain is far and away the longest, so I've got a nice 6.5" of grain coupler on each end. I've taken several measures to tame the erosivity of the motor (grain lengths and differing formulas in the top and bottom), so the grains should burn out pretty close to at the same time. I'll put some RTV on there when I load the motor just because I'm paranoid, and we're marching on.
Bottom pin ring looking sexy as we mill the top one:
The completion of the upper pin ring marked the conclusion of the machinist's involvement, a moment I had been dreading. I swallowed hard, cut a check for over half the value of my checking account total, packed up my car, and left.
"This is why I've been flying standard thick-wall hobby cases all these years and why my outcomes have been so limited...because I didn't want to do this."
On the way home, the gluttony, the exhaustion, the whole lot of it got to me so I had to pull over and just think on it for a while. I thought about the merits of passion and dedication, my obsessive personality, when dedication becomes ignorance and selfishness, and all those close to me that I've alienated (some beyond repair) over the years in my pursuits that make sense to few. Yep, we've had these moments before! Like, last month for Aeronaut, waking up at 4am for practices in college, and every mountain I've climbed. Welcome to TNDO (take no days off) week people - an annual (in this case biannual) tradition!
This guy came to speak at UNC a couple of times, and I used to listen to this stuff on repeat during low moments in college. Gets me going every time, and Lord knows I need it this week:
[video=youtube;x0a7Hi51b3s]https://www.youtube.com/watch?v=x0a7Hi51b3s[/video]
Wednesday
I can barely remember what happened during the day on Wednesday...about mid-way through TNDO weeks I'll start chugging EmergenC to avoid getting sick for the launch due to lack of sleep. I'm really, really looking forward to fully investing myself in my month-old job when I get back from Black Rock.
After work, I headed to Rice University to meet up with Random Flying Object, who makes satellite electronics for a living. Can't imagine a better guy to modify my Telemetrum. Left Rice at about 8:30, got home at 9...time to go to battle again with the Cotronics. We last touched base on the fillet sanding last Thursday; though I'm now feeling very behind on my fincan, since last Thursday, we've mixed an O motor from start to finish, and machined a hardware set from start to finish. Pretty cool. Man your battle stations:
The therapeutic part about sanding the fillets is that it's linear - time invested = outcome achieved. So many other elements of this (and any other) project are the things where you'll waste hours or days going down a road that ultimately leads nowhere.
So, in the wee hours of the morning, our fincan is finally ready for layups:
The Ryan and David-inspired before and after sanding mass check confirms our WW3 with the Cotronics resulted in an 80g mass savings!
The third-shift cashier at the checkout station with the Mountain Dew cooler at Wal Mart can't get rid of me these last couple of weeks - so of course, when I walked in to work this morning, it seems to have followed me here:
Tonight, I finally get to lay up my fincan, the last major construction step and one I always look forward to. It's actually kind of fun!
Tomorrow will be tying up loose ends - applying ablative to the fincan, gluing the grains into the liner, cutting av bay bulkplates - and then I'll wake up Saturday morning and drive three hours to Jim's house (much easier than the 20-hour round trip to drop off my stuff with Manny for Aeronaut!) and drop everything off.
We're actually getting there. I can see it now.
prophecy
So, in the wee hours of the morning, our fincan is finally ready for layups:
The Ryan and David-inspired before and after sanding mass check confirms our WW3 with the Cotronics resulted in an 80g mass savings!
The third-shift cashier at the checkout station with the Mountain Dew cooler at Wal Mart can't get rid of me these last couple of weeks - so of course, when I walked in to work this morning, it seems to have followed me here:
Tonight, I finally get to lay up my fincan, the last major construction step and one I always look forward to. It's actually kind of fun!
Tomorrow will be tying up loose ends - applying ablative to the fincan, gluing the grains into the liner, cutting av bay bulkplates - and then I'll wake up Saturday morning and drive three hours to Jim's house (much easier than the 20-hour round trip to drop off my stuff with Manny for Aeronaut!) and drop everything off.
We're actually getting there. I can see it now.
prophecy
