There Is No Why (screw it, I'll try a P)

[mrwalsh85]

The process you've described is called portable line boring. This a common practice for maintaining large machinery on site. Usually these setups use a single point HSS or carbide tool. There should be tons of information available on the web about it.

I've seen this done in steam locomotives -- where they are boring the valve cages for the steam locomotives... They don't want to take the valve cages (which have the timing ports) out, for fear of losing any timing accuracy they have. Thus, they bore them in place. Plus, some are two-piece valve cages, so getting the distance between them correct can understandly be an issue.

 

[Barkley]

Hey Edward,

That would be awesome, thanks so much!

The tube is a flat 5.00" OD, so 4.988" would be the max OD to allow for the .006 that in my experience is necessary for a decent slip fit.

Looking to purchase a 5 foot length, nominal 1/8" wall 6061-T6 (tube, not pipe).

Would gladly pay you some commission for your troubles.

Best,

Steve

I know this may seem simple, but have you called Metal Supermarkets? I got my mandrels from them, but for your purposes I'm certain they could get you what you need. They asked me to spec the OD/ID/thickness/length etc. You mention you're in Houston - I've used the MS on Corporate Drive near Sugarland.

 

[prophecy]

I know this may seem simple, but have you called Metal Supermarkets? I got my mandrels from them, but for your purposes I'm certain they could get you what you need. They asked me to spec the OD/ID/thickness/length etc. You mention you're in Houston - I've used the MS on Corporate Drive near Sugarland.

Hey Barkley,

Thanks for the suggestion - I haven't called Metal Supermarkets. If I'm going to mail order the tube (or have them mail order the tube), I may as well get it from Online Metals - cracking the code here would mean hunting around a warehouse for something that's just out-of-spec enough to suit my needs, as Edward's going to do.

Do they have a big warehouse with stuff on the shelf, or are they a reseller that will get it shipped to them per order? Important distinction in this case...

Thank you

S

 

[Barkley]

Hey Barkley,

Thanks for the suggestion - I haven't called Metal Supermarkets. If I'm going to mail order the tube (or have them mail order the tube), I may as well get it from Online Metals - cracking the code here would mean hunting around a warehouse for something that's just out-of-spec enough to suit my needs, as Edward's going to do.

Do they have a big warehouse with stuff on the shelf, or are they a reseller that will get it shipped to them per order? Important distinction in this case...

Thank you

S

Small warehouse, but MS is a chain, so others have lots of stock. I'm 90% sure when they order in it's from other MS stores, so you aren't dinged the extra. I'm certain they could get you what you want.

But I get your point - if you're looking to bring your tube to the warehouse and try a bunch of stock until you find one 0.006 out of spec, I doubt that would be the place to do it.

 

[Barkley]

Another thought. When I make tubes I use a mylar film on the mandrel sprayed with Frekote, so when I pull the tube off the mandrel the removal of the mylar guarantees a tolerance for slip fit. Want me to make you a tube? I know this is apples and oranges, but tube I made for my 38mm MD build came out pretty well:

EDIT - guess the attach photo function is still down. The pic I was going to share is in post 18 of my Flying MooMoo build thread, and it shows the motor closure threading extending beyond the wall of the tube. My point being you could loan me your case, I could put mylar around it and make your tube, and you could name your thickness.

 

[AlphaHybrids]

Would you choose snap rings over a pinned closure if possible? I have access to a lathe and nice steady rest that can do lengths that long.

Edward

 

[prophecy]

Took a sardine can flight up to Chicago over the weekend to see some friends in Chicago and hit MWP with Manny for a few days, and there were some developments on this project as a result.

First, got my liner in the mail on Thursday - one sexy piece of phenolic (well, actually two). Seeing the quality of this tempts me to dial up the Aluminum even more than Sunday Silent just so the awesome liner is used to its full potential. TBD. Anyway, Nemo was excited to check it out:



Manny and I got to the field about 4am Saturday morning and passed out in his car for a few hours. Woke up to the sound of pouring rain at about 8am - with no signs of letting up. Saturday at MWP was a complete wash, so when life gives you lemons, best be making lemonade. So Manny and I drove down the street, busted out RASAero, and finalized designs of both his 4.5" project and my 5" project. David and Tim joined our party, everybody translated their designs to .dxf format, and the CNC was fired up:



Those are my fins on the bottom and Manny's on top.

Cut and cleaned up:



Beveled:



Since returning from Balls, I've had a rule that each night I need to spend 15 minutes cleaning G10 dust out of my apartment from the Sunday Silent effort. I'm nearing completion, but I'm still not done over a month later. So, the rain on Saturday that forced us inside had a silver lining of saving me having to cut, edge and bevel the fins in my apartment and starting the cleanup process all over again, and for that I'm tremendously grateful. First time I've ever been glad it rained at a rocket launch.

I'd been kicking around what I wanted to do about the motor tube/airframe tube tolerance issue in my head for the last week or so, and over a game of pool on Saturday night a conclusion was reached. I ordered this morning a nominal 5.00" OD tube from Online Metals (Edward - I can't get away with a snap ring design in a 5", 1/8" wall case where the bearing thickness is actually 1/16"). It'll be shipped to an old NC buddy of mine who's a wizard with composites (those of you that know Charlie will know what I'm talking about), and he'll use my specific tube as a mandrel to make a tube that'll match the .090" wall of the RW nosecone with .005" Mylar as a release agent, thus fabricating the requisite .005" of clearance that was the whole issue in the first place and eliminating the whole shaving issue.

Sunday dawned bright and clear, so Manny and I punted up the tracking system used at Balls in Gus Piepenburg's N10000 project, another feather in the hat so we should be set to go for tracking both of our projects in NM (nice flight, Gus!).



Got on the plane last night with no headache whatsoever, I swear, and feeling better about getting kicked out of neutral on this project. Sometimes a weekend with old rocket friends is all you need.

Still on the slow track here, but slow is a relative term in my world. Stay tuned.

-sh

 

[prophecy]

The dominoes are starting to fall here. We have our ossified parameter now - the actual tube - so we can get building around it.

Spent a couple hours last night mulling my final propellant config in the gym, where all the best design work happens, and consulting some friends before freezing the design. Had to happen sooner or later, because I'm picking Manny up at DFW on Friday night and the mixer won't be turned off for a few days. Since I'm limited pretty severely by my liner here - it's 50" L so I'm limited to roughly 49" of propellant and can't simply buy another piece to splice on top - my emphasis will be on volume loading to compensate. Upping volume loading is easy if you're running a conservative formula (gotta keep the mass flux down), but one defeats the purpose of the other. I've spent a couple weeks playing around with different tricks to get the best of both worlds in my head, and ironed it all out into a final config over the last couple of days after talking with some friends.

Now that I've got the actual dims of the tube, I shored up the design of the pin rings and bulkhead so Dan can get going on turning them (I sent him material weeks ago before being stymied by the tube tolerance issue). Knowing him, he'll have it done in no time, and the parts will be on their way to me along with my chunk of graphite that's at his place. Once I get the graphite, I can hit up the Colombian machinist I found operating out of a storage unit a few miles outside of town, and he'll buzz out the nozzle on his CNC. A friend will be 3D printing the pin drill jig to my spec, and I'll drill the pin holes at my place with my $13.88 Wal-Mart brand drill (take that, expensive milling guy).

Then, all that will be left is the typical side work of fincan/av bay (from my days of working security at a bar, "side work" equated to mopping up puke and picking up broken glass in the 3-4am hour, still have nightmares when I hear that term. But, it's the only appropriate way to describe building a fincan and av bay on projects that are indubitably motor-centric).

Updates should be coming more frequently now, I'd better ensure that's the case if I want to avoid another Mountain Dew shitshow. T-2mos exactly

steve

 

[mannyskid]

Steve training for the Trimodal AP blending World championships.



The solution to not having the correct size casting bases.

 

[SS/EA 6BBL 71 Cuda]

Steve training for the Trimodal AP blending World championships.

View attachment 276173

The solution to not having the correct size casting bases.

View attachment 276174

My GOD Manny! :surprised: What are you feeding Steve? Thanks for the great picture too Steve...(of Chicago Fire at MWP13)!

Manny? This where i go into my little voice-Uncle Gus is planning to be at XPRS next year. Vacuum Bagging Stuffage ordered. Project angles being worked out right now as we think. Bidding for days of vacation coming soon at work. Might need some pad help-age. Your going to like this one. Secret, secret...NO questions right now.:no:

 

[ECayemberg]

My GOD Manny! :surprised: What are you feeding Steve? Thanks for the great picture too Steve...(of Chicago Fire at MWP13)!

Manny? This where i go into my little voice-Uncle Gus is planning to be at XPRS next year. Vacuum Bagging Stuffage ordered. Project angles being worked out right now as we think. Bidding for days of vacation coming soon at work. Might need some pad help-age. Your going to like this one. Secret, secret...NO questions right now.:no:

Hmm, I may have to have a little chat with Uncle Gus! You drivin there Gus?

Steve and Manny; looking good! Have fun in the lone star state and say hi to Mr g for me. If you venture west a bit, perrinis ranch in buffalo gap is a neat place to eat; great steaks!!!

Have a blast, gents!

Eric

 

[SS/EA 6BBL 71 Cuda]

Hmm, I may have to have a little chat with Uncle Gus! You drivin there Gus?Eric

Brother Eric! Why YES i am planning to drive there. I've got an eight foot bed that never has to be made. My project will only need the backseat...Wah!

 

[mannyskid]

Steve had to pose with his cast propellant. The casting base made from a lamp worked flawlessly.



Working again through lunch, we had been working so long, our rhythm was applied to other aspects of our day.



All in all, after working for 30 hours with a 4 hour sleep break in between, we have finished mixing and packing 45kg of propellant or roughly 90,000 Ns.

 

[prophecy]

Apologies for the vapid update, but I'm hoping to keep this current, and today is my deadline for over 50k', so no time like the present.

Three weekends ago, Manny and I totaled 4 hours of sleep, and it took four days to reach that total (Friday-Monday). I added 860 miles of driving on top of that, but that's all in the rearview because we got all the New Mexico propellant made.

Last Monday, I was able to get some time on my buddy's dedicated propellant chop saw, and pulled an all nighter taking advantage of it to get all 103.4 pounds of propellant cut. The 10" saw was too small for my 4.475" OD grains, so it took a few passes with the requisite half-cut approach (tweaking the Harbor Freight saw exhaustively to be accurate to the tenth of a degree and disobeying the "approximated" factory square settings; small deviations from square are magnified in a half-cut arrangement, and with my particular motor design square grain faces are absolutely critical). I lost 9/16" of propellant total over the eight grain faces getting this right, meaning it took me roughly 1/16" of material per grain face to get it perfect. Not too bad, especially for doing it on my knees on my buddy's back porch with a floodlight at 4am on a Tuesday morning. The perfectionist in me is annoyed at the lost impulse. Oh well. I'll more than likely have surgery over the holidays, and the launch will be under our noses right after the New Year, so it was imperative to get as many time-intensive operations (like mixing and cutting the propellant) as possible done. Feels great to have that whole thing off the table.

In the meantime, my friend has finished printing the pin drilling jig, and it's been sent to Charlie for test fitting over the motor case (which is currently serving as the mandrel for the tube Charlie is making):



Pin ring (fore and aft) designs, as well as closure and nozzle design, was finalized last Wednesday and manifested in a series of dimensional drawings and CAD renders. Two separate machinists (graphite and non-graphite) will be making the parts sequentially since all of my stock is in one place - Dan P. will be making the aluminum parts, and once he's finished, Arcesio can get going on the nozzle. The hardware design is a natural progression from what worked on Sunday Silent, focusing on areas where it was felt that further mass reduction could be realized. Same thing with the propellant - the formula is tailored to accommodate my desire for improved volume loading as compared to Sunday Silent, but with the same underlying principles that worked well on SS in both geometry and formulation. The propellant physically looks awesome (good density), so this motor should be pretty solid (85%, to be specific, hah):





Half of my motor chilling with Randito's motor:



In other news, I caught a flight to an MDRA launch a few weekends ago to assist my dad with a years-long initiative that the time had come to try. It had been a while since I'd seen Randito, so he made the trip down to hang out and even fly a rocket. Just for kicks, we talked on the phone a few days before and decided he'd make a downscaled version of the Sunday Silent motor (formula/geometry) and fly it in his Extreme Wildman that has over 50 flights on it. Every other 4700 load he's flown in that rocket got 11.5, he got 13.5 with the SS formula and accompanying increased vol loading. A 17% performance increase in a small motor. That gap will be magnified in a larger motor, and it was cool to see the concepts scale so well, especially with all the residence time pundits around the hobby EX community. Nice flight, Randito.

As I recover from surgery, the one objective will be to get the fincan done. I plan to use the same approach that worked on SS, but I'll have to find a way to do it without the benefit of my equipment, since surgery and subsequent recovery will be in the New York area. Minor detail, I'll figure it out.

If I can emerge on 1/1/16 with a completed fincan and completed motor parts, all I'll have to do in the first two weeks of the new year is assemble the motor (a b!tch with the single use pinned design, but it could always be worse) and cobble together an av bay using the Sunday Silent electronics. Still toying with the idea of flying a camera but we'll see, maybe the camera mass would be better assigned to Nemo in his quest to become the world's first stratospheric fish.

This timeline is a layup, I kinda like it.

-s

 

[FredA]

OK Steve -- can you be more specific about what got you a 17% increase in performance? Sounds a little too good to be true or you baseline was super-cheese.

 

[prophecy]

OK Steve -- can you be more specific about what got you a 17% increase in performance? Sounds a little too good to be true or you baseline was super-cheese.

13.5k/11.5k = 117%.

Not a sterile experiment by any means, and not even my data - but serves as contextual validation in the residence time debate, among other things. Randito's historical favorite formulas are 68/10, catalyzed Mg/Zn white, and Blue 22 (78/2/2), so pretty middle of the road in terms of performance of hobby propellants (if it was sparky, or red, or something, that would be a "super-cheese" baseline). He wanted to fly a more efficient motor, hence his desire to try the formula I ran in Sunday Silent at Balls. The basis of my vignette was his remark upon the 13.5xx beepout: "I've never beaten 11.5 with this rocket/hardware combo, ever" which serves as an empirical data point that the significant added Aluminum content as opposed to 68/10 (remember, the formula was developed with a larger motor in mind) was combusted, not wasted as many would have you believe. The boon of 68/10 (as opposed to something like 72/10) is that it allows one to choke down the cores while maintaining a reasonable mass flux because of its low solids loading, but this is often a moot point because the propellant's mediocre ISP cancels out the benefit of the higher volume loading it allows. The goal of the SS motor was to tweak the chemistry to boost ISP while maintaining the ability to choke down the cores a la 68/10 (leveraging Oxamide, AP particle distribution, metals content, etc.) Randito's motor used a standard spiral liner, but the geometry and good bonding allowed the liner to slide out despite a very high metals loading.

Like many things, this is an iterative process, and one I've got working in harmony with a similar evolution process in the hardware design space with the end goal of making a more efficient motor overall. Sunday Silent was the beginning of my journey and v1.0 on my specific formula and hardware design, and to that end, TINY can be considered v1.1. That said, this is a battle Al, Ryan, David, James and others have been fighting for a while now. Each of those people did something demonstrably different from established norms in a certain space, and Sunday Silent was my own feeble attempt to recognize a synergy between the three:

-James flew a fully airframed fiberglass rocket with an 80 solids motor to 54k' by virtue of an entirely original fin design;
-Ryan and David showed how mass-inefficient most hobby rockets are by doing a series of projects that re-examined every single component, re-defined what was really necessary, shaved each one down to the bare minimum, and returned very impressive results;
-Al took a standard (HEAVY) 3/16" 98 hardware set and an even clunkier two-tube dual deploy Mongoose 98 and tossed it 60k' by virtue of volume loading unprecedented in hobby motors.

I've been fortunate to have some sharp minds in the hobby and professional space to bounce my ideas off of occasionally and reassure myself that I'm on the right track, so it's just been a matter of finding what works for me and filtering that through the lens of what's available to me in terms of chems and machining (you'll note I'm running graphite/aluminum nozzles still, since my outsourced CNC machining makes a three-piece nozzle cost prohibitive), deciding how far I'm willing to push it, and making it my own.

I'm tweaking the propellant to take this idea a step further in the 5" motor since so far, so good (note the goofy small core in the grains pictured). There's a million ways to skin this cat, I'm just going off of what works for me and using the chems I have available to me. Randito's flight was another arrow pointing in the direction of "so far, so good."

Thanks for following along.

 

[butalane]

OK Steve -- can you be more specific about what got you a 17% increase in performance? Sounds a little too good to be true or you baseline was super-cheese.

Increased pressure, increased volume loading, increased aluminum, addition of fine particles...

A 17% bump puts a 200s ISP formula right at the measured ISP of the formula SS was based on.

Then again, not sure what about the claim makes it "super-cheese" in the first place - most hobby motors are pretty under-performing.