E or F 24mm single-use booster motor?

[Charlweed]

I am looking for a high-thrust 24mm diameter single use booster motor. Estes Es don't have enough thrust. A 70mm length would be ideal, but Santa has not answered my postcards yet.
My design needs high average thrust on ignition, and other considerations disqualify re-usable motors for this stage.

I fear I must modify some existing motor, but if if there is an off-the-shelf product out there I will be a happy customer.

Thanks!

[Jerry Irvine]

I am looking for a 24mm diameter single use booster motor. A 70mm length would be ideal, but Santa has not answered my postcards yet.
My design needs high average thrust on ignition, and other considerations disqualify re-usable motors for the booster stage.They used to be common. Not so much anymore.

1/32" per second of delay reduction to no less than 1.5 second net since the delay is also the bulkhead. Who said that?

Jerry

USR 24mm from the olden days. (http://v-serv.com/usr/24mm.htm)

A quick internet search showed ZERO motors currently available suitable for modification to suit this goal. That is a "bad thing".

[ghrocketman]

There are ZERO single motors available to do this like the old F100's
You could cluster 3 D12-0's in the booster for the equivalent of a 51 n-sec 'baby-F' F36.
Gap/passport stage them to a single upper-stage D12, E9, or E12

Instead of that you could use electronics for staging.

[luke strawwalker]

I am looking for a high-thrust 24mm diameter single use booster motor. Estes Es don't have enough thrust. A 70mm length would be ideal, but Santa has not answered my postcards yet.
My design needs high average thrust on ignition, and other considerations disqualify re-usable motors for this stage.

I fear I must modify some existing motor, but if if there is an off-the-shelf product out there I will be a happy customer.

Thanks!

How about an Estes D?? It has MUCH more initial thrust than the Estes E9... (well, I say that, but now they have the E12... which is pretty much identical to the D12 but with a longer burn duration, AFAIK...)

What do you need this for? Any details on your project??

Using a composite in the first stage will mean you have to have an electronic ignition system for the upper stage, period... either timer or altimeter based. Composites cannot directly ignite and upper stage motor like BP motors can.

Modification of motors is strictly prohibited by the safety codes. I trust you're aware of that (and if not, you are now). It's not particularly safe, because modifications to an existing motor design, unless you REALLY, REALLY know what you're doing, is more likely to make the motor go "BOOM!" than make it perform better... (and somehow I doubt you have the skills or knowledge to modify a motor successfully, even if it were permissable, since you're having to ask around here to even see what's available commercially, which is a pretty simple and straightforward thing to do using a little research online...

Your best alternative would be to use a clustered first stage... a PAIR of D12's or E12-0's should have plenty of thrust on liftoff... 3 D12's surely would... Or a central 24 mm D12 or E12 flanked by a pair of C6's... C6-3's could even eject a chute or streamer for your booster stage if desired...

No modification necessary, and if you use Quest Q2G2 ignitors, that really simplifies cluster ignition and adds a lot of reliability.

Later and good luck with your project! OL JR :)

[Doug Sams]

I am looking for a high-thrust 24mm diameter single use booster motor. Estes Es don't have enough thrust. A 70mm length would be ideal, but Santa has not answered my postcards yet.
My design needs high average thrust on ignition, and other considerations disqualify re-usable motors for this stage.

I fear I must modify some existing motor, but if if there is an off-the-shelf product out there I will be a happy customer.I've been dealing with and contemplating this issue for a few years. Alas, I haven't done squat with it in months to advance my state of the art. Nonetheless, here's how I see it. There are three or four ways to go.

1. As mentioned herein, one fairly straightforward approach is to use a clustered booster which uses conventional BP style staging to the sustainer. I've built several of these and flown them all with good results. Here are a few links:

Clustered booster to single-motor sustainer:
http://www.doug79.com/midget70/
http://www.doug79.com/apogeedx/

Clustered booster to clustered sustainer:
http://www.doug79.com/midget80/
http://www.doug79.com/thridget70/
http://www.doug79.com/thridget60/

In the case of the rockets with single-motor sustainers, it's important to use a burn string (http://www.doug79.com/burn-string/) on the booster to ensure it doesn't leave the pad without lighting the center motor.

2. Using a composite booster. Although the E12 is an improvement over E9, it's still a fairly mild average thrust number for an E motor. So, while there are no high average thrust BP motors, there are some high thrust composites. For example, in reloadables, Aerotech makes an E28, an F39 and a D24, all of which have decent lifting power.

With one of these, the idea is to trim the delay fairly short, but not down to 0. There needs to be enough delay material (web thickness) in place to ensure the delay doesn't blow thru while the propellent is thrusting under high pressure. The delay is the forward pressure bulkhead. Nevertheless, while coasting is not an ideal scenario with the heavy, staged rocket climbing slowly skyward, some coast time is necessary to because the delay cannot be trimmed too short. So the composite booster motor needs to impart enough speed to the heavy rocket to not only get it going, but to tolerate the deceleration during the coast time.

2a. Assuming all the trimming and coasting works out, the next trick is getting the sustainer lit. One concept that I want to try one of these days is to use the burning thru booster delay to light the sustainer motor ala BP staging. Ted Macklin and I want to try this some time, but I keep weasling out on him. Seems like all I do nowadays is work on my kids' projects - mostly their cars - instead of working on mine. Anyway, one additional thought is to put a dash of ejection charge powder (ie, 4F BP) in the booster motor delay well to help ensure the sustainer lights.

I have a half finished rocket I built for this experiment. One of these days I'll get it all-the-way done :(

2b. Rather than using the motor burn thru to light the sustainer, the HPR technique of using electronics can be employed. Whether it's a complex flight computer or a simple rocket timer, the electronics are triggered by the acceleration, then they fire the sustainer as programmed by the user. This means the sustainer can be lit before the booster delay burns thru thus avoiding the aforementioned coast time issue. Also, in this case, the booster ejection event can be used to deploy a recovery system for the booster stage (rather than using the traditional tumble recovery).

3. One thing I've been wanting to experiment with, IF I can collect sufficient SAFETY equipment like asbestos gloves and a lexan shield, is to core some BP motors. The idea is to take a D12 and turn it into a ¾D30 or C40 by enlarging the nozzle and increasing the depth of the bore (ala how Estes would bore C6's into B14's, for example).

No doubt, this is potentially dangerous, and, even with that addressed, I have no idea what the optimum bore shape would be.

At the woodworking store, they have some conical drill bits that seem like a good starting point, but it's only a swag at which one to use. One thought is to get a hand cranked drill chuck which can be mounted thru a piece of lexan. The motor would be anchored in a clamp and the the user would hand drill SLOWLY behind the protection of the lexan.

Again, these are only some thoughts on the matter. I would want to investigate the matter in more detail - to add more safety margin - before embarking on such an experiment.

But one could use it to make B14's out of C6's and C40's out of D12's. Furthermore, one might even make a wicked D50 out of an E12.

Once done, the motors would need to be tested in a stand. The idea for a D40 might just fizzle and end up being an E2 - about like a delay grain ;)

In summary, there is no F100 as GH mentioned, but there are several possible workarounds with varying degrees of difficulty, complexity and possible danger.

Doug

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