LPR Multi Staging.

[Mopower71]

I have never launched a multi staged rocket. Never have found a launch location that I could get away with it, or should I say recover it.
But, here's my :eek: cRaZy :eek: question....
What is the maximum number of possible stages in a LPR?
How would you do it, Start with an E for max power at lift off, then step down in sizes?
What do you think the MAX altitude you could achieve?

[bernomatic]

I have never launched a multi staged rocket. Never have found a launch location that I could get away with it, or should I say recover it.
But, here's my :eek: cRaZy :eek: question....
What is the maximum number of possible stages in a LPR?
How would you do it, Start with an E for max power at lift off, then step down in sizes?
What do you think the MAX altitude you could achieve?

First Restriction is weight. According to the NAR Safety code LPR can weigh no more than 53 oz at lift-off

[bernomatic]

From the NAR Safety Code


7. Size. My model rocket will not weigh more than 1,500 grams (53 ounces) at liftoff and will not contain more than 125 grams (4.4 ounces) of propellant or 320 N-sec (71.9 pound-seconds) of total impulse.

In my thread regarding my conversion of an Estes new style Renegade D into a two stage, I did some theoretical designs using E9's and adding two additional E-9 to the side pods and attained an altitude of around 4,200 feet using RockSim. :cool:

Of course the first problem you have is finding an engine to lift everything off the pad with.

[Doug Sams]

What is the maximum number of possible stages in a LPR? Aside from the administrative and legal issues of max weight and HPR certification, there is a practical limit. 3 stage rockets can be flown with good probability of success using 1 BP motor in each stage - that is, with minimal complexity.

Under the right conditions, you can fly four or five stages, but the success rate drops very fast, and the conditions require calm air, a large field, a well crafted rocket and lots of helpers to track all the pieces.

How would you do it, Start with an E for max power at lift off, then step down in sizes?
What do you think the MAX altitude you could achieve?No, the Estes E's thrust curve is not well suited for use as a booster (hence, why they don't offer a booster version).

I'd say your best bet would be to buy one of the multi-stage kits and start there. The Estes Comanche is a good 3-stager. (Add vents to the first stage for the most reliability.)

Ignoring any HPR cert's or FAA mass limits, it's conceivable to build a multi-stager using several motors per stage thereby allowing more stages. But such birds are quite complex and very demanding to be successful. One rocketeer, Boris Katan (sp?), has staged rockets employing 10's of Estes D-motors - quite impressive.

So, flying over 3000' is not a big stretch, but 2500' is pretty much the limit using 1 motor per stage (as on the aforementioned Comanche).

Doug

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[Mopower71]

I didn't even thing about multi engine stages.

It just a hypothetical what if.
Rules and regulations aside, I just wanted to see if others had thought about it, and what they came up with.

So flying close to a mile up would be possible starting with multiple D's.
What would this rocket look like in your eyes. big on the bottom, and as the weight was reduced as it was dropping stages, it would reduce in size and amount of engines burning at once down to the size of a Wizard final stage, OR ?

[Doug Sams]

So flying close to a mile up would be possible starting with multiple D's.
What would this rocket look like in your eyes. big on the bottom, and as the weight was reduced as it was dropping stages, it would reduce in size and amount of engines burning at once down to the size of a Wizard final stage, OR ?That pretty much describes any stager - getting smaller as stages are shed. And getting sleeker, too, since the upper stage fins tend to have more sweep (but not always).

Here's one that's only moderately complex. And one of my favorites. It's a Tuber with an added booster stage. It uses 3xC6's and a D12-0 to a D12-0 to an E9-6. Doug .
http://www.doug79.com/tuber/tuber-asa-pan2p.jpg (http://www.doug79.com/tuber/#uber-tuber)

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[Joe Wooten]

Back in the 80's I built a 3 stage rocket using 24 mm D engines. I flew it once using a D12/D12/D12, and somehow managed to get all the pieces back. The next time I used 3 modified Marcus strap-ons with C5-0 engines in them. I found the first stage, all three strap-ons, but lost the second stage and watched as the upper winds carried away the main body off to Never Land. I used a streamer for recovery of the 3rd stage, but the winds up at whatever altitude it hit were much. much faster than the measly 5-6 mph bressze on the ground.

[Mark II]

Back in the 80's I built a 3 stage rocket using 24 mm D engines. I flew it once using a D12/D12/D12, and somehow managed to get all the pieces back. The next time I used 3 modified Marcus strap-ons with C5-0 engines in them. I found the first stage, all three strap-ons, but lost the second stage and watched as the upper winds carried away the main body off to Never Land. I used a streamer for recovery of the 3rd stage, but the winds up at whatever altitude it hit were much. much faster than the measly 5-6 mph bressze on the ground.Yeah, you might have hit the jet stream on that motor combination! :eek:

[Joe Wooten]

Yeah, you might have hit the jet stream on that motor combination! :eek:

The kids who gathered around while I was launching had a blast watching it. They were why I got everything back on the first launch. One of the smart-a$$ ones told me after we watched the 3rd stage drift away during the second launch that God wanted his rocket back.