RadManCF
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[POW]Eagle159;250343 said:Marbels?
You know the machine Estes came up with for mass producing BP motors? It's called a Mabel.
[POW]Eagle159;250343 said:Marbels?
You know the machine Estes came up with for mass producing BP motors? It's called a Mabel.
The shape of the core is limited by the process, and the core shape is what makes the difference between a somewhat agressive thrust curve (B8/C5) and a very aggressive thrust curve (B14).Well, Estes is able to press dimples into BP grains at high speed, how would a core be different? I've looked at some other posts on this same subject, and it is apparently possible to press cores into BP grains using a hand press, Why shouldn't it be possible in an automated machine? My first guess would be space constraints in the Mabels...
[POW]Eagle159;250320 said:Heat?
Did the B14 need any special igniters? like the composite engines?
The shape of the core is limited by the process, and the core shape is what makes the difference between a somewhat agressive thrust curve (B8/C5) and a very aggressive thrust curve (B14).
When the BP is being pressed against the pintle (the core forming die), its shape affects how well the BP gets packed, and hence the burn characteristics. If the sides of the pintle are too steep, as needed for a B14, you won't get tightly packed powder, but you may get either a swollen motor case or a kaboom motor or both.
Basically, while the ramming processing is sorta like hydraulics, it's not really that. I suppose there's some science of deformable solids mixed in. What this means is that, unlike hydraulics, the pressure inside the motor case is not uniform during ramming - it is affected by the shape of the pintle - hence, you won't be able to satisfactorily pack the BP when using a very agressive core shape. The only way to get that is to pack it normally, then drill it out to the agressive shape.
Or, settle for a less aggressive burn ala a B8.
At least, that's my interpretation.
Doug
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As I understand it, the motor case, with nozzle in place, is set over the pintle, powder is poured on top, then the ram comes down packing the powder into the case. This is repeated until all the powder has been poured. Then the delay is added in a similar fashion, followed by the (loose powder) ejection charge topped by the cap.So, is the grain formed by pressing the pintle into an uncompressed grain, or is the BP pressed around the pintle?
When the BP is being pressed against the pintle (the core forming die), its shape affects how well the BP gets packed, and hence the burn characteristics. If the sides of the pintle are too steep, as needed for a B14, you won't get tightly packed powder, but you may get either a swollen motor case or a kaboom motor or both.
Basically, while the ramming processing is sorta like hydraulics, it's not really that. I suppose there's some science of deformable solids mixed in. What this means is that, unlike hydraulics, the pressure inside the motor case is not uniform during ramming - it is affected by the shape of the pintle - hence, you won't be able to satisfactorily pack the BP when using a very agressive core shape. The only way to get that is to pack it normally, then drill it out to the agressive shape.
.
As I understand it, the motor case, with nozzle in place, is set over the pintle, powder is poured on top, then the ram comes down packing the powder into the case. This is repeated until all the powder has been poured. Then the delay is added in a similar fashion, followed by the (loose powder) ejection charge topped by the cap.
Doug
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No, I think they already use a ring-shaped ram to get what core they have. But no matter how much y-force they press it with, they don't get enough radial force to pack the powder tightly enough to the pintle (in a cored motor such as the B14). Or maybe the outward radial force - hydraulic effect - ruptures the case. Either way, they can't ram a core as aggressive as the B14 - they have to drill it.So, given all that, it seems to me that in theory, if the BP were added a bit at a time, and a ring shaped ram were used to compact to compact the grain around the pintle, a pressed core burner would be possible. do you think this is the case?
[POW]Eagle159;250320 said:Did the B14 need any special igniters? like the composite engines?
Why is it not amenable to mechanization, and how is it hard on the tooling?
Well, Estes is able to press dimples into BP grains at high speed, how would a core be different? I've looked at some other posts on this same subject, and it is apparently possible to press cores into BP grains using a hand press, Why shouldn't it be possible in an automated machine? My first guess would be space constraints in the Mabels...
So, is the grain formed by pressing the pintle into an uncompressed grain, or is the BP pressed around the pintle?
Drilling creates friction - friction creates heat and BP has a low ignition point. Every now and then one would go WOOSH during the drilling.[POW]Eagle159;250339 said:I think someone will have to help us on why it is soo unsafe to core BP...
Plus, pintles that are that thin tend to break easily under the ram pressure that is used for BP motors.The shape of the core is limited by the process, and the core shape is what makes the difference between a somewhat agressive thrust curve (B8/C5) and a very aggressive thrust curve (B14).
When the BP is being pressed against the pintle (the core forming die), its shape affects how well the BP gets packed, and hence the burn characteristics. If the sides of the pintle are too steep, as needed for a B14, you won't get tightly packed powder, but you may get either a swollen motor case or a kaboom motor or both.
Basically, while the ramming processing is sorta like hydraulics, it's not really that. I suppose there's some science of deformable solids mixed in. What this means is that, unlike hydraulics, the pressure inside the motor case is not uniform during ramming - it is affected by the shape of the pintle - hence, you won't be able to satisfactorily pack the BP when using a very agressive core shape. The only way to get that is to pack it normally, then drill it out to the agressive shape.
Or, settle for a less aggressive burn ala a B8.
At least, that's my interpretation.
Doug
.
Also, black powder doesn't ignite and burn like composite propellant. Igniting any portion of the B14's core will ignite all of the core nearly instantly. Cored composite motors, on the other hand, have to be ignited from the top of the core or else they will not burn properly. APCP combustion is pressure-dependent; a composite propellant motor has to build up enough pressure in the combustion chamber very quickly after ignition in order to burn properly. Black powder does not have this requirement. Coring a black powder motor simply provides a much larger surface area that burns, causing the motor to consume its propellant very rapidly. The total impulse of the motor is delivered in a small fraction of a second, which was why the B14 had such a kick.Back in those days the igniters were just pieces of nichrome wire. You could form a loop around a small rod, stick it in the nozzle, and push in a small wad of paper behind it to hold it in place against the fuel grain. Later Estes came out with their special igniter that was a heavier wire but with a zone that was squeezed down to be thinner, and coated with their special pyrogen. The igniters came as one long straight wire the could be cut into 3 separate igniters. You would fold them in half, stick them in the nozzle, and push a wad of paper in behind them. With either of these igniters it didn't matter what the nozzle size was, you just used a larger or smaller wad of paper. The current igniters with plugs are a bit easier to use, and if you lose the plastic plugs you can still use the small wad of paper to do the same job.
Why is it not amenable to mechanization, and how is it hard on the tooling?
So, is the grain formed by pressing the pintle into an uncompressed grain, or is the BP pressed around the pintle?
So, given all that, it seems to me that in theory, if the BP were added a bit at a time, and a ring shaped ram were used to compact to compact the grain around the pintle, the issues of non uniform pressure in the case could be reduced. Do you think this is the case?
It's amazing how this topic came up on YORF a while back and how it has migrated over here.
This issue with the B14 has always been, and will always be, this question: Can this motor be made safely AND economically.
There is no doubt whether or not if the technology to manufacture these motors consistently and accurately exists. The machinery/practices can be made to make the manufacturing safe. So it really comes down to the economics: will the costs of manufacturing, etc., be less than the revenue generated from the motors in the span of say two years. I am thinking that the answer is "no".
You could have a "boutique" motor manufacturer make these and sell them for $24.99 a pop (pun intended), but would anyone pay that? I would guess that a few would. But I guess that quite a few would take a pass at the high price point.
Unless that happens, we can dream about how that "back in the day" you could go into a hobby shop and buy a B14, and then go to your local Dodge dealership and buy a Charger with a Hemi.
Oh wait ... you can get a Charger with a Hemi now.
Hmmmmmm....
Greg
It all comes down to a "Coolness" factor. Who is the coolest dude?
A: A handsome young buck in his newly leased, fuel injected Charger with a three pack of SU D21s he just bought from valuerockets.com on his mobile phone,
OR
B: A crusty old fart in an original carbureted Charger he just paid $50,000 for, having to put additives into his gas to get it to run, and with a diamond pack of B-14's he just bought off of EBay for $50 plus shipping.
ANSWER: B The crusty old fart because he has A LOT more cash to spend trying to recreate what is was like back in the day and to compete with all those handsome young bucks!
Nope. Just the regular igniters.
Although the igniter does tuck up a little deeper into the nozzle. Other than that, I've never noticed any difference in ignition characteristics.
You can, with a little careful tinkering, get a modern Estes igniter to do the job, but with such a precious motor I would use something better.
It all comes down to a "Coolness" factor. Who is the coolest dude?
A: A handsome young buck in his newly leased, fuel injected Charger with a three pack of SU D21s he just bought from valuerockets.com on his mobile phone,
OR
B: A crusty old fart in an original carbureted Charger he just paid $50,000 for, having to put additives into his gas to get it to run, and with a diamond pack of B-14's he just bought off of EBay for $50 plus shipping.
ANSWER: B The crusty old fart because he has A LOT more cash to spend trying to recreate what is was like back in the day and to compete with all those handsome young bucks!
Whether the white plug will work depends on which version of the B14 you have. Some of the later B14 nozzles appear to actually be the size of B8's leading some to speculate Estes changed the designation some time after the nozzle was changed.It doesn't take any tinkering. Just load the igniter as you would any "normal" motor.
Although the nozzle aperture is wider than any current Estes motor, so no "ignition plugs" from existing motors will work on B14's -- although I suspect the white plugs from D/E motors might possibly work, I just use the time-honored technique of tamping in a small wad of wadding to keep the igniter in place.
It doesn't take any tinkering. Just load the igniter as you would any "normal" motor.
Although the nozzle aperture is wider than any current Estes motor, so no "ignition plugs" from existing motors will work on B14's -- although I suspect the white plugs from D/E motors might possibly work, I just use the time-honored technique of tamping in a small wad of wadding to keep the igniter in place.
Heck, you've got to straighten the ignitor legs to get them into many of the current motors. For sure, the A10, but I find others needing it, too. So that's a common need. It doesn't disqualify using them in the B14. That is, you don't need anything special for B14's other than doing something to retain the ignitor....but a normal Estes igniter these days, with the short neck bent in the wire and paper/tape way up high, just didn't have the length to get up into the core.
Well, they do say a fool and their money are soon parted... and Fleabay pretty much proves the point...
Later! OL JR
This issue with the B14 has always been, and will always be, this question: Can this motor be made safely AND economically.
There is no doubt whether or not if the technology to manufacture these motors consistently and accurately exists. The machinery/practices can be made to make the manufacturing safe. So it really comes down to the economics: will the costs of manufacturing, etc., be less than the revenue generated from the motors in the span of say two years. I am thinking that the answer is "no".
You could have a "boutique" motor manufacturer make these and sell them for $24.99 a pop (pun intended), but would anyone pay that? I would guess that a few would. But I guess that quite a few would take a pass at the high price point.
Greg
Maybe the guy I know was not working with a true Estes B-14, but a normal Estes igniter these days, with the short neck bent in the wire and paper/tape way up high, just didn't have the length to get up into the core. The plastic D plug really didn't work in the big nozzle either. Some of the older guys said it was better to ignite them a little farther up than at the base of the powder core, then went on to tell stories of FSI CATOs in the good old days of core burnin' BP. That might have just been a story too, hard to say as a BAR.
The guy I know did end up using some stock igniters from an older pack of Estes motors where they were a bit longer than the new ones, and they worked fine. But from what I saw he just used a bit of tape or put a kink in one of those fancy Q2 igniter holders instead of the old school recovery wadding technique . . . that would have been so cool to see, a slight lick to moisten the little clump of wadding then tamp it into the nozzle, would have instantly taken me back to the 70's.
The current bend to the Estes igniters are so short that some of the first time kids and their parents have a real problem getting them to even touch the powder in a normal end burn motor without smashing the wires together or making a big mess with the paper tape and plug, resulting in numerous shorts and burn outs at the mass launches. If the B-14 was produced today I could just imagine all the poorly constructed High Fliers with Scouts sticking in an B-14 for a first time flight:y:
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