Estes core burners?

[RadManCF]

Marbels?

You know the machine Estes came up with for mass producing BP motors? It's called a Mabel.

 

[[POW]Eagle159]

You know the machine Estes came up with for mass producing BP motors? It's called a Mabel.

I did not know that...thanks for telling.

 

[plano-doug]

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...

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

.

 

[JStarStar]

Heat?

Did the B14 need any special igniters? like the composite engines?

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.

 

[RadManCF]

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

.

So, is the grain formed by pressing the pintle into an uncompressed grain, or is the BP pressed around the pintle?

 

[plano-doug]

So, is the grain formed by pressing the pintle into an uncompressed grain, or is the BP pressed around the pintle?

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

.

 

[RadManCF]

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

.

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?

 

[plano-doug]

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?

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.

doug

.

 

[bjphoenix]

Did the B14 need any special igniters? like the composite engines?

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.

 

[Bazookadale]

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?

I have a B14 in front of me - the centerbore is very narrow, no more than 1/16" - I don't have a gauge handy to check. I drop a wire into it and the bore is an inch deep. Imagine pressing powder along such along narrow pintle at 1000 or more pounds of pressure - it wouldn't take long for the pintle to bend or break.The "dimples" as you put it are wider and shorter, therefore use a sturdier tool. And yes the powder is pressed around the tooling.

 

[Bazookadale]

I think someone will have to help us on why it is soo unsafe to core BP...

Drilling creates friction - friction creates heat and BP has a low ignition point. Every now and then one would go WOOSH during the drilling.

 

[MarkII]

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

.

Plus, pintles that are that thin tend to break easily under the ram pressure that is used for BP motors.

 

[MarkII]

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.

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.

 

[luke strawwalker]

Why is it not amenable to mechanization, and how is it hard on the tooling?

Long pintles used to make core burners are more prone to breakage and experience higher friction and impact loads when the motors are pressed mechanically. In addition, there's a higher risk for propellant cracks from the pintle extraction. That's why the Estes motors were drilled.

Not sure about the FSI coreburners...

Don't want to get too deeply into it because I'm not an expert in this area, but I've read a lot about it. I also got the Teleflite Corp. Sugar Motor book years ago and was considering getting into that and they also described possible issues with the tooling, and those were "hand pressed" motors.

It's not that it CAN'T be done, but for MASS PRODUCTION it's a whole other ballgame.

Later! OL JR

 

[luke strawwalker]

So, is the grain formed by pressing the pintle into an uncompressed grain, or is the BP pressed around the pintle?

Look at the end of a BP motor. The pintle is the part that makes the nozzle shape and the dimple in the end of the BP core. If you look closely you'll notice that the clay will usually have a little "flash" around the edges, sometimes even bits of clay embedded in the dimple of the BP. This is caused by how the motors are pressed.

AFAIK, the way it works is the motor case is slid down over the pintle (which is basically a metallic insert the shape of the nozzle and grain dimple) and then the clay "crumbles" are dumped in around the pintle to make the nozzle, then the BP is dumped in and pressed to make the propellant grain. Could all be done in one step as far as I know. The clay and propellant both have a specific amount of moisture in them to allow them to "flow" and meld together with the other particles/casing around them when they're pressed. The hydraulically powered ram comes down and presto-- instant motor. Next the delay powder (different slow-burning smoky BP formulation is dropped in and pressed, (again with a specific amount of moisture so the particles "flow" together under pressure and form a "solid pellet" of material when pressed) and then the dry particles of BP are dumped on top for the ejection charge, and the clay cap pressed on top of it to hold the ejection charge BP particles in place.

So, you can see that basically you want as short a pintle as you can get. If you try to press the BP over a long, slender pintle, it's going to create some difficulties. First, the long slender pintle is going to be prone to breaking off, because if it gets slightly misaligned and is hit by the ram coming down around/over it, it's going to get smacked and bent. Second, the ram itself will have to have a bore hole up into the center of it to clear the pintle, and BP will tend to ram up in there and gum up the works, again creating friction and clearance problems in continuous production. Thirdly, as a thought experiment, think about packing tiny balls of Play-Dough into a tube-- it has to be packed into the tube tightly enough that they're all squeezed together and all the air is squeezed out. Which is going to be easier to consistently get a good job packing in it in there?? Using a short pintle to make the nozzle end and dimple shaped like a pen cap, or using a long slender pintle shaped like the whole pen sticking halfway up the tube?? Of course it's easier to get a consistent job with the shorter pen cap "pintle".

Theoretically you probably could use the pintle to ram the propellant and clay from the nozzle end, and using a flat "anvil" and make the motor "upside down" but then again, I think it'd be problematical. You need the highest ramming pressure on the nozzle end of the motor, so doing it backwards would be very difficult IMHO. Usually there's just enough pressure on the clay cap to "smoosh" the clay bits together and lock the ejection charge grains in place. Pressing the motor "backwards" like this would put the entire press pressure on the clay cap and ejection charge, possibly pressing it into a "pellet" of BP which wouldn't "explode" to eject the chute, merely burn like an extra bit of propellant. That wouldn't be good. Plus, dumping the propellant charge in and then the clay on top, and pressing the pintle down through it, will tend to push a LOT of clay bits down into the propellant as you press the pintle down through it to form the core... meaning a LOT more "inclusions" on the propellant core face, leading to erratic ignition and burn when the motor is first ignited (due to the unburnable clay stuck into the face of the propellant core surface). For these reasons I don't think it's a viable way to make a motor. Consistency is a VERY important trait for machine manufactured ANYTHING-- if every third or fifth or tenth one is prone to "go boom" or not work it's going to be unacceptable.

Later! OL JR

 

[luke strawwalker]

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?

That's how the Teleflight Sugar Motor cores were pressed, but those were HAND PRESSED motors... and it was a risky proposition at that...

The tooling was all to be made from brass, turned down on a lathe to the proper contours of the pintle/ram according to the blueprints in the book. There were also instructions on making a "blast shield" out of heavy steel plate, with a small hole in it just large enough to clear the ram with a bit of space around it. You inserted the pintle into the casing and the casing into a steel collar (to prevent the motor from swelling and splitting the casing as you pressed it) and then dumped some clay (rock-hard water putty IIRC) into the bore around the pintle, inserted the ram (which had a blind "pilot hole" drilled in it to clear the pintle) and then smacked it with a hammer HARD to press the clay. Then you removed the ram, dumped the "sugar powder" into the casing around the pintle, inserted the ram, and smacked it with the hammer again (staying well clear of the ram in case the powder ignited or went off, which would send the ram flying up out of the hole like a bullet-- the blast shield was supposed to protect you from the 'explosion'... Then you removed the ram, dumped in the slow-burning sugar powder for the delay train and rammed it, and then dumped some BP on top and capped it with clay or paper/tape. Note this is about three press operations... at a minimum... AFAIK the Mabels press the motors all in one step... just dump the ingredients in the case like a layer cake on top of the "dimple pintle" (clay, propellant, delay, ram at high pressure, then dump in the ejection charge grains and the cap clay and press lightly to seat it. (I'm pretty sure the ejection charge and clay cap are pressed MUCH lighter than the nozzle/propellant/delay train are pressed-- look at the clay cap end of a motor sometime-- you can still see the small "prills" (balls) of clay are just "smooshed" enough so they stick together... too much pressure and the BP ejection charge and clay would get hopelessly pressed together and turned into a solid pellet like the delay/propellant grain... The ejection charge BP MUST be in a "loose powder" type of form (ok, tiny grains with a lot of surface area) to burn fast enough to eject the chute-- it's the difference between the effect of the loose propellant grains in a rifle cartridge and the solid slug of BP in a model rocket motor-- the more surface area, the faster the burn... that's why if the propellant cracks or separates from the casing wall (usually from improper storage) the motor will "explode" (cato or casing rupture). The crack or separation increases the surface area enough that the propellant burns too quickly, overpressurizing the casing and rupturing it forcefully).

If you've never seen a B14 up close, they have an ENORMOUS nozzle... the nozzle extends almost to the casing wall and the hole in the nozzle at the forward end (the narrow end) is about 1/4 inch in diameter-- about the size of the WIDE OUTLET END of a typical BP motor nozzle!) This was to prevent case overpressurization from the VERY RAPID (short duration) propellant burn time compared to "regular" model rocket motors. A smaller nozzle would hold too much back pressure in the casing and result in the motor going "boom"... which basically when you get into very short duration motors you start flirting with the line between "whoosh" and "boom".

Later! OL JR

 

[gpoehlein]

This might be a good oportunity to point to the only (as far as anyone knows) video of the original Mabel running:

https://www.vernestes.com/Photos and Videos.htm

The video isn't very clear and you can't see that much, but the description to the right does tell a bit about the process.

 

[GregGleason]

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

 

[Daddyisabar]

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!

 

[GregGleason]

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!

 

[Daddyisabar]

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.

 

[JStarStar]

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 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.

 

[luke strawwalker]

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!

Well, they do say a fool and their money are soon parted... and Fleabay pretty much proves the point...

Later! OL JR

 

[plano-doug]

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.

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.

Notice that the two B14's on the left have much larger nozzles than the 3rd B14, right of center. Its nozzle appears to be more like the B8 far right. The one caveat is that its core is deeper than the B8's, 0.75" vs 0.6". That is, despite the seemingly smaller nozzle (of the B14 right of center) its core has the same depth as the two cored units on the left.

Close-up of the nozzles.

The B14 right of center would apparently use the light blue igniter plug of the B8 while the two larger nozzles would maybe use the white or black plugs of the D12 or E9.

Doug

.

 

[Daddyisabar]

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.

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:

 

[plano-doug]

...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.

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.

Doug

.

 

[Daddyisabar]

Well, they do say a fool and their money are soon parted... and Fleabay pretty much proves the point...

Later! OL JR

Good to see the young bucks chiming in! Just wait another 20 or so years and you have cash and want your old toys back, foolish things will happen as you seek that long gone E9 motor, remembering only the wonderful long burn and slow lift offs of the very expensive and hard to find D Region Tomahawk kit. And $100,000 dollars for the smell of fossil fuel burning EVO - a real bargain to you!

 

[jim fustini]

Well, all I can say is thanks to everyone for the wealth of information I have gotten from this thread. That is what TRF is all about. I sure would be cool to have the B-14 back , but I guess those days are over. Please keep the replies going. Also If anyone has any photos of B-14 motors from their private collections or any BP coreburners please post them. Videos of flights would be cool too. This forum is great. I learn something new every day Thank you gentlemen.

 

[RadManCF]

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

Thanks for the responses everyone. I had thought that perhaps the issue with pressing a core burning BP engine might have been something to do with the limits of travel of the rams in the mabels, but it seems that there are more issues. I was just curious since there seem to be many people that miss these motors.

 

[JStarStar]

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:

I don't think there's any significant difference as far as whether you ignite your B14 way farther up the core or at the base of the BP (that is, I don't think there's any advantage in trying to insert your igniters way, way up the center-bore). I think as long as the igniter is in physical contact with some part of the BP grain you get essentially the same results.

I think at the instant of ignition hot burning gases fill the entire "combustion chamber" at more or less the speed of sound and any exposed BP ignites within a couple thousandths of a second and very quickly you are at full thrust.

I agree that the current "stock" Estes igniters sometimes cause problems because the lead wires are bent at such an angle to make proper insertion into the motor nozzle difficult (and then if you try to bend 'em back, sometimes the squib coating crumbles off).

Since my secret stash of B14-0's all include the old Estes 3-to-a-strip nichrome-pyrogen igniters, and my 1970s-vintage launch system is wired to handle it, I usually just use those to light 'em off. I just bend 'em far enough to get up into the nozzle and in contact with the BP (as you would with any motor), tamp in the wadding, hook up the leads and go.