Lets talk about Staging LPR vs MPR and/or clustering

[jqavins]

So, after all this new information you could (if you want) stick with single stages like: two new rockets, one 18 mm and one 24 mm, both either minimum diameter or close to it, built of slightly stronger stuff like papered fins and epoxy construction. Place Quest or Aerotech D motors in the 18 mm and Aerotech E and F motors in the 24. Watch'm soar to remarkable heights, if you don't lose sight of them in the first 200 feet because they're going so fast! All the talk of staging is good and valid, but not necessary for a while.

The Apogee Aspire, which takes 29 mm motors, can break mach 1 on a high thrust motor or break 1 mile on an Apogee (Aerotech manufactured) F10.

 

[jlabrasca]

Ok here's a design:

That's a basic design of a three stager that (according to OR) will carry 20g to 40g to 4000 ft and/or break the speed of sound, depending on various motor configurations and payloads.

I love that fact that the stages are interchangeable, so that just a 19mm booster and a 24mm booster. But if you use a D12 (or that F44 ) then stage 2 is falling from 400 ft and its going to need a recovery system. Which means electronics to light stage 3.

I'm not there yet, but I can build this and start flying it with Bs and Cs.
And then get there.

Thoughts?

I think there are red exclamation points on every simulation. Are you getting "large angle of attack" warnings?

Also, the F44 is a composite motor.

 

[BDB]

Any configuration having an AP motor will require electonic ignition. Only your first example wouldn’t. That means that you would need to build avionics bays into at least one of the stages and then run wires to attach to igniters in the second and third stage motors.

Here’s an example of an APCP 3-stager that you might find interesting:
https://www.jcrocket.com/fleetlist.shtml
(Follow the ‘Comanche 3 Upscale’ link. I can’t figure out how to copy and paste a direct link.)

 

[BDB]

I think there are red exclamation points on every simulation. Are you getting "large angle of attack" warnings?

Good catch. I zoomed in on the motors and didn’t pay attention to the exclaimation points. Heed the warnings!

 

[BDB]

Those are cool.

(The reason professional hand models exist:

)

EDIT: (after reading more about them) OH I SEE, those are very cool.

LOL! That is one nasty looking thumbnail!

I haven’t flown QJets yet. Can they be directly staged like BP motors?

 

[jlabrasca]

LOL! That is one nasty looking thumbnail!

I haven’t flown QJets yet. Can they be directly staged like BP motors?

What a good looking question!

The answer is almost certainly "no".

They are composite motors, so you could not use them for upper stages.

It would be an off-lable use of the product, but the flame-thrower ejection charge we observed from the first iteration B4 and A3 motors sure seemed like it might ignite a BP motor. The shortest available delay is 4 seconds -- so it would seem an undue risk to test this application.

 

[Brainlord Mesomorph]

Sorry guys, I haven't been clear.

I'm a BAR who hasn't ever launched a two stage rocket.

I'd like to go from where I am to being a guy with complex electronics bays with flight computers doing mid flight ignition, two-stage recovery, radio telemetry, GPS locators etc. Once I have all that tech under my belt, I'll be able to go higher and faster knowing I'll be able to land and recover the rocket. The "Zed Lifter Program" is a (personal) experimental rocketry program of sorts.

The Zed One (my 2nd rocket in 40 years) barely got off the pad. The Zed 2 reliably lifts 22g to 600 or 700 ft on C engines. (but you don't need ebays to go 700ft)

The Zed III is my test bed to go from 700 ft to 4000 ft and to figure out the ebay and the mid flight ignition, two-stage recovery, radio telemetry, GPS locators etc.

So, Yes I know the bottom of that list would involve some very complex electronics, THAT'S THE IDEA.

 

[Brainlord Mesomorph]

dupe post deleted.

 

[Brainlord Mesomorph]

The bangs (exclamation points) are all "Discontinuity in diameter" errors (?) and chutes ejecting at high speeds.

anyone want the ORK file?

 

[Charles_McG]

Despite what OR says, to my eye those fins look little. Have you looked at the stability as a 2-stage and as a single stage?

I’m not sure I trust OR’s handling of long thin fins - I’ve watched it’s optimization routine run off the rails.

Also, you might want to try to sim the boosters by themselves. They should be unstable so they tumble. I have watched a fat finned ( long root, not thick ) with luck-of-the-build balance glide down. My last Vigilante flight had the booster come in ballistic (normally tumbles) and it banged up the coupler.

 

[Brainlord Mesomorph]

So, after all this new information you could (if you want) stick with single stages like: two new rockets, one 18 mm and one 24 mm, both either minimum diameter or close to it, built of slightly stronger stuff like papered fins and epoxy construction. Place Quest or Aerotech D motors in the 18 mm and Aerotech E and F motors in the 24. Watch'm soar to remarkable heights, if you don't lose sight of them in the first 200 feet because they're going so fast! All the talk of staging is good and valid, but not necessary for a while.

The Apogee Aspire, which takes 29 mm motors, can break mach 1 on a high thrust motor or break 1 mile on an Apogee (Aerotech manufactured) F10.

Hi Joe,
I have to just say "yes, I get it." I do understand. Yesterday, driving around I thought of it this way: SSTO is clearly the best way to orbit. As such single stage to any desired altitude would obviously be cheaper, faster, simpler, more reliable, etc. So I get that.

I get sticker shock when I look at $20 and $25 single use engines. And yes I know that to avoid using a $25 engine I'm using two $11 engines and a $13 engine AND requiring complex electronics to boot.

But that sounds like a lot more fun than just putting one $25 engine in a simple rocket and pressing go.

 

[Brainlord Mesomorph]

Despite what OR says, to my eye those fins look little. Have you looked at the stability as a 2-stage and as a single stage?

I’m not sure I trust OR’s handling of long thin fins - I’ve watched it’s optimization routine run off the rails.

Also, you might want to try to sim the boosters by themselves. They should be unstable so they tumble. I have watched a fat finned ( long root, not thick ) with luck-of-the-build balance glide down. My last Vigilante flight had the booster come in ballistic (normally tumbles) and it banged up the coupler.

I scaled them down on the upper stages. My thinking is that as we get higher and faster we need less fin.
It adds 300ft to the max Ap and 50 mph. Even with as little as 20g of payload, top stage stability is 1.25, middle is 2 (better with more)

Sim plots look good as a two-stager and even just the top stage alone.

EDIT: oh, as for stage recovery, once I have electronic staging, I'm thinking the 2nd stage booster will have a chute.

 

[jqavins]

I didn't mean to imply that you don't get it; sorry if I did or if I oterwise offered offense. I gained a (false?) impression from the OP that you were just a little reluctant to add to the complexity of your rockets, and you were preparing to do so because you'd gone as high and fast as you could on ingle stage C motors. If adding stages is the goal then, by all means, go for it. If the goal remains, as stated in the first sentence of the OP, to go higher and faster, then even BP D and E engines give you a lot of room to grow, and single stage composite motors give you even more. But now I'm repeating stuff you already get, so I'll stop.

One last thing. In regard to "two stage recovery", you keep using those words, and I'm not so sure they mean what you think they mean. Are you talking about recovering a rocket (or the sustainer stage thereof) with two "stages" in the recovery? Such as a drouge chute and a main chute? If so, that's called "dual deployment". I've never heard of "two stage recovery" but it sounds like adding a recovery system to a booster so that both stages have them. (Which, of course, is also necessary when staging at high altitude.)

 

[Brainlord Mesomorph]

One last thing. In regard to "two stage recovery", you keep using those words, and I'm not so sure they mean what you think they mean. Are you talking about recovering a rocket (or the sustainer stage thereof) with two "stages" in the recovery? Such as a drouge chute and a main chute? If so, that's called "dual deployment". I've never heard of "two stage recovery" but it sounds like adding a recovery system to a booster so that both stages have them. (Which, of course, is also necessary when staging at high altitude.)

sorry "dual deployment"
(but I'm actually also thinking of a chute on stage 2)

EDIT: Zed 4 may very well be be a 29mm single stager. (maybe 24)

 

[lakeroadster]

.....
Now they’ve divided it into Class 1 (model rockets up to 1500 grams and specific impulse requirements - no waiver needed)....

Steve, Could you elaborate on the specific impulse requirements?

 

[jlabrasca]

The bangs (exclamation points) are all "Discontinuity in diameter" errors (?) and chutes ejecting at high speeds.

I will echo and amplify what CharlesMcG advises -- check the stability stage by stage.

Also check the stability of the stages as components.

Also, figure out what is making OR throw the warnings, Your sustainer delays all look pretty close the the "optimum" -- so the high speed deployment may be an artifact cause by issue

Sorry guys, I haven't been clear.

I'm a BAR who hasn't ever launched a two stage rocket.

https://www.apogeerockets.com/Tech/How_2-Stage_Rockets_Work

(scroll down to the references)

Steve, Could you elaborate on the specific impulse requirements?

I am not Steve, but look at the NAR site

https://www.nar.org/high-power-rocketry-info/

Where Is The Line Between Model and High Power Rocketry?
A rocket exceeds the definition of a model rocket under NFPA 1122 and becomes a High Power rocket under NFPA 1127 if it:

• Uses a motor with more than 160 Newton-seconds of total impulse (an “H” motor or larger) or multiple motors that all together exceed 320 Newton-seconds;
• Uses a motor with more than 80 Newtons average thrust (see rocket motor coding);
• Exceeds 125 grams of propellant;
• Uses a hybrid motor or a motor designed to emit sparks;
• Weighs more than 1,500 grams including motor(s); or
• Includes any airframe parts of ductile metal.

In addition, a rocket exceeds the definition of a model rocket under FAA rules (FAR 101.22) if weighs more than 1500 grams (53 ounces).
​

 

[jqavins]

I'd venture that Steve's "specific impulse" was a misstatement. The requirements relate to total impulse. As you (and Steve) probably (both) know, specific impulse is a whole different thing. I have never heard of any limits on specific impulse, and I can't imagine a reason that there should be one.

 

[Steve Shannon]

Steve, Could you elaborate on the specific impulse requirements?

Doh! I am sorry. I didn’t even think of how my phrasing misrepresented what I was trying to say. I meant there are specific requirements regarding total impulse. I didn’t even consider “specific impulse”

Here’s the actual wording:
§ 101.22 Definitions.
The following definitions apply to this subpart:

(a)Class 1 - Model Rocket means an amateur rocket that:

(1) Uses no more than 125 grams (4.4 ounces) of propellant;

(2) Uses a slow-burning propellant;

(3) Is made of paper, wood, or breakable plastic;

(4) Contains no substantial metal parts; and

(5) Weighs no more than 1,500 grams (53 ounces), including the propellant.

(b)Class 2 - High-Power Rocket means an amateur rocket other than a model rocket that is propelled by a motor or motors having a combined total impulse of 40,960 Newton-seconds (9,208 pound-seconds) or less.

(c)Class 3 - Advanced High-Power Rocket means an amateur rocket other than a model rocket or high-power rocket.

[Doc. No. FAA-2007-27390, 73 FR 73781, Dec. 4, 2008]

Note that the only total impulse requirements apply to the distinction between Class 2 and Class 3 rockets.

 

[Steve Shannon]

I'd venture that Steve's "specific impulse" was a misstatement. The requirements relate to total impulse. As you (and Steve) probably (both) know, specific impulse is a whole different thing. I have never heard of any limits on specific impulse, and I can't imagine a reason that there should be one.

You are correct. Thanks for the lifeline and the generous assumption that I knew the meaning of Specific Impulse.

 

[Brainlord Mesomorph]

You are correct. Thanks for the lifeline and the generous assumption that I knew the meaning of Specific Impulse.

LOL you meant "particular impulse", not "specific impulse".
I wondered what Isp had to do with it.

 

[Steve Shannon]

LOL you meant "particular impulse", not "specific impulse".
I wondered what Isp had to do with it.

Actually I meant requirements specific to impulse. It was very poorly worded given the specific meaning of Specific Impulse. [emoji16]