Black powder rocket questions

[stckmndn]

Dear buttercup,

 

FF makes their tooling to fit the tubes they sell and same goes with SL. Firesmith, Wolter, and Dag make their tooling to fit the NEPT tubes. Believe it or not there is a difference. NEPT tubes are manufactured to a much higher tolerance. The other tubes are sloppily made and loose on the spindles. Too loose, in fact, to use.

 

My other pet name for you was darling.

 

But you have now graduated to Nancy.

[Mumbles]

Seriously, shut the hell up stckmndn. I don't want to have to sit here and babysit you while you continue to stir up shit.

 

The simple solution is to e-mail Rich Wolter or Ben Smith and ask if their tooling is machined to fit a certain tube, or it it's all pretty much universal. I will say that I know clam shells and other things that are designed to fit an OD typically are machined to fit. There is more variance in OD of tubes based on preference (thick vs. thin wall), and manufacturer/supplier.

 

One notable exception to the ID thing is with spolette tubes. There are a few major suppliers, and they all seem to have different standards. They will all be a little different, so you'll need tooling specific to them.

[ausgoty]

Seriously, shut the hell up stckmndn. I don't want to have to sit here and babysit you while you continue to stir up shit.

 

The simple solution is to e-mail Rich Wolter or Ben Smith and ask if their tooling is machined to fit a certain tube, or it it's all pretty much universal. I will say that I know clam shells and other things that are designed to fit an OD typically are machined to fit. There is more variance in OD of tubes based on preference (thick vs. thin wall), and manufacturer/supplier.

 

One notable exception to the ID thing is with spolette tubes. There are a few major suppliers, and they all seem to have different standards. They will all be a little different, so you'll need tooling specific to them.

 

 

To be fair I think firebird threw the first salvo followed by sarcastic baiting by stckman. Fault on both sides IMOP.

 

 

There is some good discussion in between the waffle!

[allrocketspsl]

To be fair I think firebird threw the first salvo followed by sarcastic baiting by stckman. Fault on both sides IMOP.

 

 

There is some good discussion in between the waffle!

 

well i missed it somewhere but anyway the idea of making tooling fitting tubes is alot more realistic than the other way around,NEPT has most likely been rooling for years,like a hunfred?For the life of me I will never understand why people dont roll there own.

[nater]

well i missed it somewhere but anyway the idea of making tooling fitting tubes is alot more realistic than the other way around,NEPT has most likely been rooling for years,like a hunfred?For the life of me I will never understand why people dont roll there own.

 

I roll some of my own tubes, especially if I want something a little different than the NEPT I have stored. The fact is, I can with 1 pound tubes and sticks from hobby horse, and some hemis from ACE pyro, I have $1 invested in materials for a single 1 pound rocket before making the comp. BP fuel is cheap to make, stars vary. That's a pretty easy investment for basic materials.

[dagabu]

I had some long conversations with Jim B. and Steve LaDuke some years ago about just this issue after I received a bundle of 3/4" NEPT tubes which my LaDuke tooling just would not fit.

 

Here is... the rest of the story.

 

Both Laduke and Wolter start with the same size material for rammers but Laduke starts with larger stock (I think 1") for the spindles. LaDuke then takes his rammers, sets them on his trusty old stump in his shop and whacks the end of the aluminum rod several times until it mushrooms out at the top.

 

The rod is then chucked up and he flattens the end and turns the crown down to .765" (shown in the picture below which is .758" due to years and years of wear and hundreds of rockets pressed). The spindle is then turned down to .775" (as shown in the second picture).

 

http://pyrobin.com/files/p1040085.jpg

 

 

 

http://pyrobin.com/files/p1040084.jpg

 

 

 

Steve told me and Jim verified the fact that the tubes are ordered to be .767" ID or so (ask Jim for the exact number) so that the TUBES fit LaDukes tooling and not vice-versa. Steve turns the rammers to .765" so that they scrape the walls all the way down the tube.

 

Not convinced? Read on and I will show you Rich's set and tell you what his wife Claudia told me when I bough the set from her.

 

I had this bundle of tubes from Jim, they were .75" ID and LaDukes tooling just would not fit, Jim offered to take them back and all but I just felt that there had to be a way to deal with this so I called LaDuke and told him I needed him to turn the set i got from him down to .75" to fit ALL of my 3/4" tubes. While he was nice and did not yell at me that day, he politely refused to do so and told me to get a set from Rich.

 

So I did. A call to Wolters and Claudia answered explaining to me that Rich was sick and couldn't talk so I asked her some questions about the 3/4' set they sold. Well, I might as well have spoke with Rich since he was answering the questions from 10' away as it was. Her explanation was that Rich made tooling to fit .750" and if the NEPT were slightly oversize, I should be OK.

 

Two weeks later I had the 3/4" UT set from Rich.

 

Rich uses .75" stock, polishes it up and you have a rammer just a .001" under that will fit all the tubes made in the 1# range. Take a look at his rammers and then the spindle base. Keep in mind that I have made hundreds of rockets with this set as well so the rammer is a little undersized like LaDukes.

 

http://pyrobin.com/files/p1040086.jpg

 

 

 

http://pyrobin.com/files/p1040083.jpg

 

In measuring the ID of the 150 odd 1# tubes I have, both the chipboard and NEPT, I find that the NEPT measure out at around .765" on average and the chipboard ones measure out at .750" on average.

 

Take this story for what it is worth to you, I am not calling anyone out or presenting it as the Word of God, it is my story and gosh darn it... I'm sticking to it!

 

-dag

Edited December 6, 2011 by dagabu

[killforfood]

Looks like I am not missing much here. Back into the shadows I go.

 

I dunno, Lurker is not such a bad occupation.

Anymore I just keep my mouth shut and read more.

It sure beats being an Anyka.

[Col]

I don`t worry if the tube id is a little too big for the tooling, too small is worse but they still come in handy for fountains and wheels with the help of an 18mm oak dowel. Tube strength is important but i wouldn`t say its everything, i use a 2.1mm wall on 1/2" id rockets (handrolled recycled kraft) and they get hit pretty hard and fast (0 - 3.55kg in 67 milliseconds according to the primitive kitchen scale test). I`ve no clue what pressure that equates to but i imagine its quite a hefty spike so there must be more variables in play than just the tube as dag said.

Regarding nozzled to nozzleless, i guess its safe to assume that if a tube can survive a nozzled motor its likely to be ok with an equivalent nozzleless motor using identical fuel?

[Peret]

I have a LaDuke set and I agree with Dag's measurements. NEPT tubes are somewhat loose, but Skylighter's chipboard tubes are an interference fit. Both work just fine but sometimes it's hard to pull the longest rammer out of the Skylighter tubes.

 

I measure the rammer at 0.752 inches.

[guntoteninfadel]

Oh the drama! And I have missed it all, damn Internet connection. As I have nothing to contribute and no new names to call anyone I will go back to my blissful ignorance of the situation. BTW, thanks dag, worked like a charm, should have vid next week.

 

Gun

[dagabu]

Oh the drama! And I have missed it all, damn Internet connection. As I have nothing to contribute and no new names to call anyone I will go back to my blissful ignorance of the situation. BTW, thanks dag, worked like a charm, should have vid next week.

 

Gun

 

SWEET! Cant wait for the video.

 

-dag

[RocketTony]

Firebird snarks - "As a total newbee it amazes me you have so much experience to share . Why are these other rockets more complicated ? I am curious."

 

Simple traditional bp rockets can be hand rammed (up to the 1 lb size). That is, the increments can be consolidated using a rawhide mallet rather than using a hydraulic press. This is a very quick and easy way to make rockets and a good reason why many beginner pyros are drawn to rocket making. These BP rocket mixtures can be made using hand screened ingredients without requiring the use of a ball mill.

 

Would you like me to continue, my little stalker darling?

 

 

 

 

 

Let me see you can hand ram a BP rocket, well if you want little to no performance then i guess you can, I have spent 8 months trying to replicate Estes end burner 3/4 ID (or 1lb rocket) motor performance and alas I have. you cannot hand ram BP motors to get the best performance they must be pressed at least to a pressure of 8,000 lbs. I use a psi gauge and run it to 1000 psi anymore than that and theres case dist oration. My rockets reach an altitude of 800-1000 feet with no problem, I don't think hand ramming is the way to go.

[Col]

I don`t understand what you`re trying to say. If you need at least 8000psi then why are your rockets performing well at 1000psi? Hand rammed bp motors work fine, pressing them gives more consistant performance but its not necessarily any better.

[allrocketspsl]

o Edited December 16, 2011 by allrocketspsl

[dan999ification]

thers no point pressing to 1000psi you can probably get the same density ramming, for anything over that to save case distortion you need a clamshell/support sleeve.

 

 

dan.

 

 

[ActionTekJackson]

Well, I don't think its in question whether or not you can or cannot ram rockets. Most all of us started by ramming them. It does work, however the work required and consistency achieved, not to mention the ability to boost performance is much greater when pressing. Plus it also opens up other rocket types such as borderline flash strontium nitrate rockets. I have done both Ramming and Pressing. Pressing is by far easier, and I've never had a cato with a pressed rocket, I wish I could say that regarding rammed rockets.

 

See for yourself, the slow rockets were usually rammed with a slower propellant to prevent CATO. The fast rockets were all pressed. The CATO rocket was also a rammed rocket by my GF (at the time, now my wife), she does not possess the... means... to successfully ram a rocket that would fly. She can however use the press to make a desirable rocket. Just my two cents...

My youtube videos

[RocketTony]

its not calculated in psi its calculated on force pressure on fuel grain, therefore 1000 psi is equal to approx 5500 pounds of pressure on fuel where 1500 psi equals approx 7800 pounds of pressure on the propellant. And yes it makes a difference in burn rate and thrust, as far as taking so long i wanted to replicate Estes exactly and i have.

I don`t understand what you`re trying to say. If you need at least psi then why are your rockets performing well at psi? Hand rammed bp motors work fine, pressing them gives more consistent performance but its not necessarily any better.

it

[Col]

It seems we were comparing apples to apples (8kpsi/1kpsi) while you were comparing apples to oranges (8kpsi/5.5kpsi)

As you can`t manage the full 8000psi without tube deformation, i`ll press a few NYE bp motors to 8000psi and a few to 5,500psi.

To my mind, if the bp is fully consolidated at 5,500psi, then pressing to 8000psi won`t make any difference.

 

Fwiw, Ned Gorski managed to replicate the performance of an estes motor using a rawhide mallet.

Neds estes motors

Edited December 16, 2011 by Col

[stckmndn]

Seriously, shut the hell up stckmndn. I don't want to have to sit here and babysit you while you continue to stir up shit.

 

The simple solution is to e-mail Rich Wolter or Ben Smith and ask if their tooling is machined to fit a certain tube, or it it's all pretty much universal. I will say that I know clam shells and other things that are designed to fit an OD typically are machined to fit. There is more variance in OD of tubes based on preference (thick vs. thin wall), and manufacturer/supplier.

 

One notable exception to the ID thing is with spolette tubes. There are a few major suppliers, and they all seem to have different standards. They will all be a little different, so you'll need tooling specific to them.

 

Sorry boss. And much as I hate to admit it, that Nancy girl firebird is right about the spindles (give or take a fraction of an inch). It's the tubes that are the biggest variable. Non NEPT tubes just suck ass.

Edited December 17, 2011 by stckmndn

[firebird]

Sorry boss. And much as I hate to admit it, that Nancy girl firebird is right about the spindles (give or take a fraction of an inch). It's the tubes that are the biggest variable. Non NEPT tubes just suck ass.

I was going to lay off you since I felt I had made my point but since you insist on being a 3rd grader with the name calling I am going to out you every chance I get.

I will also give you a fair warning be very careful about your comments. Right now your hiding behind a computer. As am I but I will promise you I do not have to.

[dan999ification]

how is 1000psi equal to 5500 pounds on the comp and 1500psi 7800 lbs

i thought force pressure is measured in pounds per square inch 1000 psi on the guage is 1000psi on the comp if the presses ram is 1" square and the id area of the motor is equal to one inch

pressing 3/4 id motors with a different sized surface area ram should see some different numbers but i thought that 1000psi is 1000psi

i dont have a press and would like to learn a bit before i get one.

 

dan.

[Mumbles]

It depends where the gauge is. If you have one of those nice P2F gauges that goes under the tooling, it will measure directly in pounds as it has a 1 sqin face. So if you want 9000psi on 3/4" tooling you multiply 9000 by .441 (surface area of tooling), and you'll get 3969, which is what you'll want the gauge to read when at the proper pressure. If the gauge is on the cylinder, you'll need to do a bit more math. Using the same example as before, you want 9000psi on your comp, which requires 3969 pounds of force. Then divide this by the area of your cylinder head to find the internal pressure you need. If you have a 2" cylinder (3.1415 sqin), you then need to press the cylinder up to 1263psi.

[Col]

Dan,

I use a homebrew PtoF, the easiest way is to make up a xls spreadsheet with all the variables Mumbles mentioned. I punch in a gauge pressure and the sheet churns out the psi for every tube id from 0.25" to 4", some sizes have several output columns to account for solid and hollow drifts.

I adjust the gauge psi until it tallies with what i need. The math is easy enough but a spreadsheet is easier first thing on a sunday morning

Edited December 17, 2011 by Col

[RocketTony]

I think not, it cant be done..... I don't really care what he says one cannot replicate Estes performance by hand ramming..... and again its not psi its force applied to the fuel grain. Its not measured in psi but i think its foot pounds.

It seems we were comparing apples to apples (8kpsi/1kpsi) while you were comparing apples to oranges (8kpsi/5.5kpsi)

As you can`t manage the full 8000psi without tube deformation, i`ll press a few NYE bp motors to 8000psi and a few to 5,500psi.

To my mind, if the bp is fully consolidated at 5,500psi, then pressing to 8000psi won`t make any difference.

 

Fwiw, Ned Gorski managed to replicate the performance of an estes motor using a rawhide mallet.

Neds estes motors

[Col]

ft/lbs usually relates to torque.

In the article, Ned tested the thrust curve and duration of the original estes motor so he had a reasonable idea of what the end goal was. He apparently reached his goal by adjusting the fuel and retesting. PSI didnt figure as a variable in the article but no doubts it was much less than 5500psi with a mallet. If the replica motor produces an identical thrust curve and duration as the original estes, then it would have to go down as a success.

Its pretty clear that PSI isnt nearly as important as the fuel and having test gear to measure everything. A psi gauge and a pair of binoculars to eyeball and guess the altitude isnt enough