Encourage Estes to make a C5-0 Booster Motor!

[Initiator001]

If the core in B14 motors was drilled, I have to wonder: why? For literally hundreds of years, skyrocket motors used a metal base, shaped to form the nozzle, and a long spindle on the base that formed the core. Being much larger than other nozzle throats, the B14 nozzle required its own metal base anyway. Why not include the long spindle and press the motors in the time-honored fashion?

Estes tried this method.

They used a pintle to form the core while pressing the B14 motor. The problem was that black powder has an adverse affect on metals and the tip of the pintle would break off at some random time during motor production.

Estes then went to the extra step of drilling the final core to turn a B4 motor into a B14.

 

[jqavins]

Do you know what bad thing BP does to metals? Metallurgy has come a long way since the B14 was discontinued, and for that matter there are ceramics that might do nicely.

 

[DigBaddy]

Let me summarize this thread:

We all want a C11-0 in an 18mm package

 

[DirkTheDaring]

Hmmmm, quite possible I am not thinking this right.

concur with both you and @jqavins that there IS a weak tail that might not be optimal. But from your statements “barely maintain velocity” and “barely 1 G during the tail”, I’m thinking’, “as long as velocity is maintained, if you got off the pad okay (when velocity is slowest) your rocket SHOULD be fine as long as it doesn’t significantly DEcelerate. If your accelerometer is measuring “1 G”, wouldn’t that rocket be at constant velocity (assuming that it’s relatively vertical)?

again, agree with @jqavins , IF you have a rocket that CAN get off the pad adequately with either C6-0 or non-existent C5-0, due mainly to (I think) the fewer newtons in the C5-0 and possibly the higher initial velocity from the C5‘s larger “spike” increased drag, the C6 is more efficient and is going to stage higher. But my target is not “rockets that could fly on both.” I’m thinking there are rockets that are too heavy (over 113 grams, per Estes motor chart) for the C6 to GET them off the rod with a stable velocity. Once it is safely off the rod, even If the motor tail can only manage 1 G, I theeeeenk velocity should be constant, so what started safe SHOULD stay safe. Even if the tail is less than 1G, is the tail THAT long that the ensuing deceleration would drop it BELOW safe speed during that 1.7 seconds seconds after the spike?

@BEC , you said your Checkmate “visibly seems to slow down” before staging, I haven’t flown accelerometers, so I is ignorant, but does your Data show it is “slowing down” or that is “no longer accelerating”?

the first is potentially a serious Problem. The second is, at worst, inefficient.

I like staging just for the point of staging, not for altitude (the latter with MODEL rockets is generally more easily achieved, at least in low power realm, with single stage bigger motor.). Okay, I do want it to at least get OFF the rod BEFORE it stages (had one that didn‘t, spent 5 or 10 minutes looking for the booster before I thought to look ON the pad!), and I don’t know, at least up 50 to 100 feet before it stages. More than that, meh, doesn’t add much for ME. I kinda like to SEE the staging, and if it is much higher than that, doesn’t add anything and kind of takes away something.

so I think that those of us whining for a C5-0 are doing so because we think it would help use with 18mm mounts that for whatever reason can’t be upgraded to 24mm (which I agree is clearly the way to go IF you can, as @jmasterj said), and that are either heavier than 113 grams and or extra draggy (which stagers tend to be the FarSide is an excellent example.) Are we wrong about that Due to the “weak tail”?

I agree

 

[DirkTheDaring]

Let me summarize this thread:

We all want a C11-0 in an 18mm package

Roughly speaking: yes.

 

[DirkTheDaring]

Hey everybody, let’s sign the petition and see how Estes reacts! We’ll take it from there.

 

[BEC]

@BEC , you said your Checkmate “visibly seems to slow down” before staging, I haven’t flown accelerometers, so I is ignorant, but does your Data show it is “slowing down” or that is “no longer accelerating”?

the first is potentially a serious Problem. The second is, at worst, inefficient.

This is an important distinction and I may have been imprecise in my description of the way that model flies on what I consider a "wimpy" A10-0T. The model clearly stops accelerating and the FlightSketch data bear that assessment out.

However, and for example, here are the data from my most recent Checkmate flight, which was last Saturday up at Sixty Acres and was, as most recent flights have been, flown A10-0T to A3-6T: https://flightsketch.com/flights/4221/

Here is a closeup of the time vs. acceleration curve, with the cursor on the point of lowest acceleration during the A10 burn.



Note that the acceleration at that point is 23 ft/s/s, so less than one G. This flight was launched by an Aerotech/Quest Phaser so I was closer to the pad than usual (shorter wires than my usual PSII controller), and as has been noted in the Sixty Acres thread, the air was essentially flat calm last Saturday. So from my vantage point almost directly underneath, this flight looked quite good, with the usual A10 "cruise" phase between liftoff and staging. Had I seen it from further away, I might have seen it visibly slow, but from where I was watching it, I couldn't tell.

But the flight continued to boost straight and after staging the sustainer leaped away, as is usual. You can see that at the end of the sustainer burn it was still accelerating at about 3 Gs then decelerated at about -3.5Gs for a brief moment as it slowed down into the coast phase. (Off the screen in that screen shot is the ejection event which was at 6.66s, so the actual delay on this particular A3-6T was more like 4.8s, which is on the short side of typical for these motors.)

I like staging just for the point of staging, not for altitude (the latter with MODEL rockets is generally more easily achieved, at least in low power realm, with single stage bigger motor.). Okay, I do want it to at least get OFF the rod BEFORE it stages (had one that didn‘t, spent 5 or 10 minutes looking for the booster before I thought to look ON the pad!), and I don’t know, at least up 50 to 100 feet before it stages. More than that, meh, doesn’t add much for ME. I kinda like to SEE the staging, and if it is much higher than that, doesn’t add anything and kind of takes away something.

I flew a Beta with a slightly more than 50-year-old (made in June of 1973) 1/2A3-0T in the booster also that day. It staged at 17 feet per these data: https://flightsketch.com/flights/4224/. That's up close and personal.

It's also interesting to see in the data, but not really germane to this discussion, that the sustainer motor on this flight burned out at 100 feet, and the model coasted to 430 feet in an additional 3.3s (delay was nominally a 4s). It would have gotten higher had the delay been as long as advertised.

so I think that those of us whining for a C5-0 are doing so because we think it would help use with 18mm mounts that for whatever reason can’t be upgraded to 24mm (which I agree is clearly the way to go IF you can, as @jmasterj said), and that are either heavier than 113 grams and or extra draggy (which stagers tend to be the FarSide is an excellent example.) Are we wrong about that Due to the “weak tail”?

I think it will really depend on the model. Much of the discussion about a C5-0 has been around fairly big models, notably Boosted Bertha. I really don't know what that one would do using this hypothetical C5-0 in the first stage compared to what it actually does with a C6-0.

The C5-3 is great for the recent heavy plastic RTF models like the Saturn V and the SLS. I saw two lovely flights on this latter on C5-3s last Saturday, courtesy of Tsolo Dan joining Ken and I.

But what really need is something akin to a C11 in an 18mm casing, as @DigBaddy mentioned above.

 

[BEC]

I like staging just for the point of staging, not for altitude (the latter with MODEL rockets is generally more easily achieved, at least in low power realm, with single stage bigger motor.). Okay, I do want it to at least get OFF the rod BEFORE it stages (had one that didn‘t, spent 5 or 10 minutes looking for the booster before I thought to look ON the pad!), and I don’t know, at least up 50 to 100 feet before it stages. More than that, meh, doesn’t add much for ME. I kinda like to SEE the staging, and if it is much higher than that, doesn’t add anything and kind of takes away something.

I meant to mention in that last post that there is, apparently, an exception to the general rule that it's much easier to get more altitude on a model than to just fly single stage, and ironically it involves these A10-0Ts. When A Payload Altitude is flown in NAR competition, the hot setup is a two stage 13mm motor model. Apogee even has a kit for this purpose called the Midge. Most of the folks flying this event (including me) and the NAR record holding flights in C (adult) and D (team) divisions are flying two-stagers boosted by A10-0Ts (and likely pistons).





But this is way off track from the original point of this thread. Sorry, Ken @DirkTheDaring

 

[jqavins]

maybe you could convince AT to make a qjet booster that could light a estes sustainer. Imagine a D22-0 instead of a c6-0.........

i know that's dreaming!

Since this thread started, I've been thinking I should go the AT open thread and bring that up. But there's a fly in the ointment. I feel pretty good about an AP motor lighting a BP motor, since the ejection charge is BP anyway. The problem is the timing of the charge; with a composite, the delay charge begins burning right away and has to continue for x seconds longer than the propellent in a [whatever]-x motor. But the propellant and delay grans each have some tolerance in their burn times, and those tolerances add up to a total tolerance in the delay, call it y. If you try to get the delay don't to zero, you actually get ±y. Since negative would be BAD, you've got to go for [whatever]-y, and may get as much as 2y. Will staging occur safely if it occurs at time 2y after burnout? Mmmmaybe.

So the question to put before AT is how small they can make y, how close can they cut it? A D16-1 could make a might fine booster under a D12.

 

[BEC]

Since this thread started, I've been thinking I should go the AT open thread and bring that up. But there's a fly in the ointment. I feel pretty good about an AP motor lighting a BP motor, since the ejection charge is BP anyway. The problem is the timing of the charge; with a composite, the delay charge begins burning right away and has to continue for x seconds longer than the propellent in a [whatever]-x motor. But the propellant and delay grans each have some tolerance in their burn times, and those tolerances add up to a total tolerance in the delay, call it y. If you try to get the delay don't to zero, you actually get ±y. Since negative would be BAD, you've got to go for [whatever]-y, and may get as much as 2y. Will staging occur safely if it occurs at time 2y after burnout? Mmmmaybe.

So the question to put before AT is how small they can make y, how close can they cut it? A D16-1 could make a might fine booster under a D12.

I think this has come up a time or three in the big Aerotech thread though it may have been around "just how far can I drill a delay, anyway?". If memory serves I think Gary said something on the order of 3 seconds. That's a long coast time on a heavy model before the sustainer ignites.

....which leads to: delayed staging is really cool to watch. MicroMaxx NE motors have no ejection charge but they do have that ~1s delay, and two-stage MMX rockets, when the work right, are great fun to see.

 

[bad_idea]

Since this thread started, I've been thinking I should go the AT open thread and bring that up. But there's a fly in the ointment. I feel pretty good about an AP motor lighting a BP motor, since the ejection charge is BP anyway. The problem is the timing of the charge; with a composite, the delay charge begins burning right away and has to continue for x seconds longer than the propellent in a [whatever]-x motor. But the propellant and delay grans each have some tolerance in their burn times, and those tolerances add up to a total tolerance in the delay, call it y. If you try to get the delay don't to zero, you actually get ±y. Since negative would be BAD, you've got to go for [whatever]-y, and may get as much as 2y. Will staging occur safely if it occurs at time 2y after burnout? Mmmmaybe.

So the question to put before AT is how small they can make y, how close can they cut it? A D16-1 could make a might fine booster under a D12.

Quite apart from the problems you mention, I can't imagine what interest Aerotech would have in making boosters specifically for a competitor's sustainers.

 

[dpower]

Back to the C5-0, yes this would be a great addition. All the benefits have been covered here, but if there was a C5-0 available, I'd rarely, if ever, use the C6-0. Estes could bring back the Farside if a C5-0 was available! When I build 3 stagers now, I try to make the 1st stage 24mm and use the C11-0. This works great for a Centuri T-Bird clone, less so for a Farside clone, which has a fragile booster when built for 24mm.

As long as we're at it, let's have a B8-0! AFAIK the B8 used the same nozzle as the C5.

 

[DirkTheDaring]

I meant to mention in that last post that there is, apparently, an exception to the general rule that it's much easier to get more altitude on a model than to just fly single stage, and ironically it involves these A10-0Ts. When A Payload Altitude is flown in NAR competition, the hot setup is a two stage 13mm motor model. Apogee even has a kit for this purpose called the Midge. Most of the folks flying this event (including me) and the NAR record holding flights in C (adult) and D (team) divisions are flying two-stagers boosted by A10-0Ts (and likely pistons).

View attachment 620834
View attachment 620827


But this is way off track from the original point of this thread. Sorry, Ken @DirkTheDaring

I'm happy to provide a place for this discussion, I think it's relevant.

 

[jqavins]

Quite apart from the problems you mention, I can't imagine what interest Aerotech would have in making boosters specifically for a competitor's sustainers.

The same interest, theoretically, as Estes might have in making engines for other people's kits: if the market exists and is profitable, they'll fill it. A competitor is not an enemy. If Aerotech and Estes could both make money by comarketing BP sustainers and composite boosters, well they'd happily do that too. Mind you, I doubt they can. But if they can, helping a competitor is no reason not to help oneself.

 

[bad_idea]

The same interest, theoretically, as Estes might have in making engines for other people's kits: if the market exists and is profitable, they'll fill it. A competitor is not an enemy. If Aerotech and Estes could both make money by comarketing BP sustainers and composite boosters, well they'd happily do that too. Mind you, I doubt they can. But if they can, helping a competitor is no reason not to help oneself.

True. I agree with your "ifs" but I also share the doubt.

 

[BEC]

As long as we're at it, let's have a B8-0! AFAIK the B8 used the same nozzle as the C5.

Sounds good.

Yes, the same nozzle, or at least close enough, since they both take the blue igniter plugs.

 

[Lord Rory Gin]

Let me summarize this thread:

We all want a C11-0 in an 18mm package

"By Jove, I think he's got it!" - Henry Higgins voice from Pygmalion.

 

[DirkTheDaring]

Hi All!

According to my weather apps, this coming Saturday, the 23rd, looks like the next decent day for sending your money up in smoke.

I know with Xmas so close this might not be possible, but think of it this way – the more rockets you lose before Christmas, the more rockets you can get as presents!

Anyway, if the weather is decent, I plan to be there, arriving my usual time around 11, plus or minus.

Ken

 

[n3tjm]

I thought I'd share my idea for a Q-jet "D16-0" fantasy motor.


Pretty much the delay and ejection portion motor is left out. Somehow the core has to be blocked at the top, maybe by simply not drilling the core all the way. Epoxy is poured on top of the propellant to seal inhibit the end and act as the fwd bulkhead. A hole that is slightly larger in diameter than the liner and casting tube is drilled down the side of the case and stops just as it contacts propellant. BP is added and capped off.

The liner may have to be epoxied into the case to prevent gasses from the nozzle end from reaching the top. Or the touch hole can be moved in a little more.

As I mentioned, this is just a fantasy....

Along with my fictional C20-0 BP motor I dreamed about for decades.

 

[Art Upton]

I thought, from decades ago that any composite non-end burning engine to be a booster actually needed a delay train that burned as long as the motor does. Then when the motor quits the delay train which is timed ignites the charge that lites the top stage.

I think some people did this way back then already in my memory. It was just not ready for prime time. Perhaps because the delay may ignite the top state before the motor really stops burning due to inconstancy in delay timing.

I think some experiments were done with say 2-4 second delays to ignite top stages even if some coast happened in-between.

 

[Alan15578]

The old C5-3 has been used as a booster motor, and the three second delay was effective in increasing altitude. YMMV

 

[SolarYellow]

I have run some sims using 18 and 24mm composites with unmodified delay timing. Even on pretty lightweight, MD rockets, the only setup that kept going straight up through the coast was an F44-4. It's the square wave of high thrust, short duration, with a quick shutoff (no "tail" on the thrust curve) and short delay that works to build the speed to keep things straight through the delay. I suppose drilling another second out of it might even help, but you legally have to be L2 & Tripoli for that, since AT has recently stated they don't want people drilling delays on preassembled SU motors.

 

[ReynoldsSlumber]

I meant to mention in that last post that there is, apparently, an exception to the general rule that it's much easier to get more altitude on a model than to just fly single stage, and ironically it involves these A10-0Ts.

Speaking of which, I was going to look into whether for C eggloft altitude it would be beneficial to parallel-stage two A10-0Ts with a core B4-2 or B4-4. But it's only worth checking out if the core motor burns significantly longer than the boosters, so that the rocket continues to accelerate with the benefit of reduced mass after the boosters kick off. With the "A10" motors smoldering along for 1.05 s (which means they are actually A2.4-0T's), that's just as long as the B4 burns for. So much for that idea! Meanwhile I also doubt it's worth looking at parallel staging with A8-0 motors, given the larger mass of the 18mm casings.

Now if we had 18mm C11-0's, a pair of those with a D12 core that could conceivably make for a real contender for E dual eggloft altitude! I'm sure that argument would convince Estes, right?

 

[Art Upton]

The old C5-3 has been used as a booster motor, and the three second delay was effective in increasing altitude. YMMV

An Article in 1974 or 75 NAR Model Rocketeer showed how to remove the Clay Cap and ejection charge from a B-2 motor to get delayed staging for greater altitude.

 

[shockie]

The current C5-3,and any proposed C5-0 are just weak imitations of the originals.

Id rather see an A3-0 so I could do some backyard staging, like I did as kid the 70's.

 

[jqavins]

I thought I'd share my idea for a Q-jet "D16-0" fantasy motor.

View attachment 642398
Pretty much the delay and ejection portion motor is left out. Somehow the core has to be blocked at the top, maybe by simply not drilling the core all the way. Epoxy is poured on top of the propellant to seal inhibit the end and act as the fwd bulkhead. A hole that is slightly larger in diameter than the liner and casting tube is drilled down the side of the case and stops just as it contacts propellant. BP is added and capped off.

The liner may have to be epoxied into the case to prevent gasses from the nozzle end from reaching the top. Or the touch hole can be moved in a little more.

As I mentioned, this is just a fantasy....

Along with my fictional C20-0 BP motor I dreamed about for decades.

I thought, from decades ago that any composite non-end burning engine to be a booster actually needed a delay train that burned as long as the motor does. Then when the motor quits the delay train which is timed ignites the charge that lites the top stage.

I think some people did this way back then already in my memory. It was just not ready for prime time. Perhaps because the delay may ignite the top state before the motor really stops burning due to inconstancy in delay timing.

I think some experiments were done with say 2-4 second delays to ignite top stages even if some coast happened in-between.

The beauty of @n3tjm's notion is that there is no delay grain. Since the propellant burns from the inside out, the flame front doesn't reach the touch hole until it's done burning. The BP filling the touch hole is just a fast burning fuse. There'd be a little staging delay, so maybe it's a D16-1 or D16-0.5, but that's close enough. I like it. (But it does sound rather manufacturing intensive, which means expensive.)

Of course, the other side of the coin is that you can't light a composite motor from a booster. Or can you? The reason you can't is that ignition has to occur at the front end of the core, but there are a few end burning composite motors; could they be lit from a booster? Imagine an F67 staging to an F10 in a min diameter rocket.

 

[jqavins]

The current C5-3,and any proposed C5-0 are just weak imitations of the originals.

Id rather see an A3-0 so I could do some backyard staging, like I did as kid the 70's.

Why not with an A10-0? That'd jump off the pad faster and then probably stay lower than with an A3.
https://www.thrustcurve.org/motors/...2310000000009&motors=5f4294d2000231000000000c

 

[prfesser]

The beauty of @n3tjm's notion is that there is no delay grain. Since the propellant burns from the inside out, the flame front doesn't reach the touch hole until it's done burning. The BP filling the touch hole is just a fast burning fuse. There'd be a little staging delay, so maybe it's a D16-1 or D16-0.5, but that's close enough. I like it. (But it does sound rather manufacturing intensive, which means expensive.)

Of course, the other side of the coin is that you can't light a composite motor from a booster. Or can you? The reason you can't is that ignition has to occur at the front end of the core, but there are a few end burning composite motors; could they be lit from a booster? Imagine an F67 staging to an F10 in a min diameter rocket.

You beat me to it. I like it; It's a wrinkle I hadn't considered. I don't know how viable the idea would be for production; pouring epoxy manually for a (relatively) few big motors is no big deal, but doing it for thousands of 18mm motors (and the hole must be drilled afterward) would be a challenge. Pyrotechnicians usually use clay for the forward bulkhead. Instead of drilling, a short mandrel that projects from the edge of the ram used to compress the clay might work.

 

[Art Upton]

The beauty of @n3tjm's notion is that there is no delay grain. Since the propellant burns from the inside out, the flame front doesn't reach the touch hole until it's done burning. The BP filling the touch hole is just a fast burning fuse. There'd be a little staging delay, so maybe it's a D16-1 or D16-0.5, but that's close enough. I like it. (But it does sound rather manufacturing intensive, which means expensive.)

Of course, the other side of the coin is that you can't light a composite motor from a booster. Or can you? The reason you can't is that ignition has to occur at the front end of the core, but there are a few end burning composite motors; could they be lit from a booster? Imagine an F67 staging to an F10 in a min diameter rocket.

I think this was done in the old days of High power with a thermalite wick in a clear tube of Teflon. The end stuck out to get ignited by the booster, it wicked up the tube to the top where a fold over 'ball' of the wick ignited the sustainer composite motor at the top.

EnerJet motors came with Termalite wick ignitors. Long versions of the "Sure Shot Dot". Instructions showed you to make a small couple of folds at the top to make the larger ignition front "ball" of flame.

 

[jqavins]

I think this was done in the old days of High power with a thermalite wick in a clear tube of Teflon. The end stuck out to get ignited by the booster, it wicked up the tube to the top where a fold over 'ball' of the wick ignited the sustainer composite motor at the top.

EnerJet motors came with Termalite wick ignitors. Long versions of the "Sure Shot Dot". Instructions showed you to make a small couple of folds at the top to make the larger ignition front "ball" of flame.

That's how the Klima motors accomplish staging.