Lakeroadster's "High School Confidential"

[ksaves2]

I remember seeing a 5 or 6 stage BP rocket fly at one of the Midwest Power launches from many moons ago. I recall it a a good flight, very high and all the stages performed. Since there were so many folks walking around during the recovery phase, meaning no launches until everyone is back at the flight line, the flier got everything back. Very entertaining and impressive to see those stages ignite in succession and a nominal flight. I recall the stages had "largish" fins that got smaller as one went up the stack to the top stage. Kurt

 

[lakeroadster]

Lake, I see above the D-C-B-A engine sequence, and that the apogee is below 800 ft. as you're wrote you're trying for. So good. But, if the true goal is "keep it low", with 800 ft. as a maximum allowed (and that's truly an "if") one could go something like D-A-A-½A. That sim could be titled "You'll find it EASY."​

This would be a visually interesting flight. Simulation looks good.​

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I agree, Joe. I'll fly this configuration.​

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Here's the statistics for the D12-0, A8-0, A8-0, 1/2A.3-2 Combo:​

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1st stage ignition: D12-0 (max Lift Weight 14 oz) Actually Lifting 10.2 ounces (1.37 : 1 Ratio)​

Max Speed: 79 mph at end of burn @ 121 feet altitude​

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2nd stage ignition: A8-0 (max Lift Weight 3 oz) Actually Lifting 8.48 ounces (0.35 : 1 Ratio)​

Max Speed: 78.9 mph, Slows to 70.03 mph at end of burn @ 203 feet altitude​

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3rd stage ignition: A8-0 (max Lift Weight 3 oz) Actual Lifting 7.59 ounces (0.39 : 1 Ratio)​

Max Speed: 69.9 mph, Slows to 68.2 mph at end of burn @ 279 feet altitude​

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4th stage ignition: 1/2A3-2 (max Lift Weight 2 oz) Actual Lifting 6.69 ounces (0.30 : 1 Ratio)​

Max Speed: 68.2 mph, Slows to 0 mph at Apogee of 457 feet​

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[jqavins]

The problem of launching a 3-stage or 4-stage and keep it under 800' seems like you would need something reasonably light but with a lot of drag, maybe BT80. I've never gotten into staging because I usually was able to get all the altitude I wanted with a single stage.

But since the design is done, the large frontal area of a BT-80 is out of the question.

Begin less important: I can see what you'd be concerned about, since it's probably a really low drag rocket, having no fins on most of the stages.

Begin more important part: He's got the sims that say it's solved. So no issue.

See, Lake, I really do trust your design skills. Sorry about jumping to conclusions about the danger GDS staging. It still sounds dicey to me, but I can't argue prior empirical success.

 

[lakeroadster]

I did, but then when I got to the 800' part that wasn't consistent with staging and I forgot all about the first post.

Not consistent with staging, based on whose criteria? I'm a scratch builder / scratch designer. Challenges are what makes this hobby interesting.​

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The problem of launching a 3-stage or 4-stage and keep it under 800' seems like you would need something reasonably light but with a lot of drag, maybe BT80.

Or reasonably heavy, with std. drag. This rocket is heavy, based on the motors being used.​

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The thing is, again, if you read the 1st post....​

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I want to revisit this design but do so in NAR safety rules compliant manner. So, this will be a 4-stage rocket. Capable of flying with 24mm D motors, but also of using 18mm motors.​

 

[Long_Gone]

"Gie me another bag of popcorn"

 

[lakeroadster]

"Gie me another bag of popcorn"

 

[cwbullet]

1976? When did you graduate?

 

[Long_Gone]

Much later, 1987. I like the Deer eating popcorn.

 

[Long_Gone]

This rocket looks cool, I would love to see it fly. 3,000+ on a bunch of D motors.................

 

[lakeroadster]

Bringing this one to the top of the build pile....

Changed the sustainer to a rear eject configuration:​

With an A3-4 motor I'm thinking it'll be easy to pop it out the back, than to clear out 12" of BT-50 and push out a 4.5 ounce nose cone.​

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Added a couple of bulkheads and my Altimeter 2​

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As a side note:​

My long time flying buddy from Grade School / High School passed away from a motorcycle accident in 2020.​

He was the one there in the hayfield, when we launched the original rocket back in 1976.​

I figure it's time to build this one and launch it.​

 

[BABAR]

How does it sim with A10-0T and A10-3T in upper stages?

The A10-3T and A10-0T motors come very close to the larger A8 motors at a fraction of the mass.

For staging, the lower mass is a bonus in making rocket lighter, so gets off the pad quicker (with same D12-0 in the first stage) and has a favorable effect on CG as well.

 

[lakeroadster]

How does it sim with A10-0T and A10-3T in upper stages?

The A10-3T and A10-0T motors come very close to the larger A8 motors at a fraction of the mass.

For staging, the lower mass is a bonus in making rocket lighter, so gets off the pad quicker (with same D12-0 in the first stage) and has a favorable effect on CG as well.

Nice! However, a quick review of the MESS report shows a high incidence of A10 cato's.​

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[BABAR]

Well, at least it’s a consistent motor!

Thanks, I never knew what MESS stood for.

 

[Daddyisabar]

Deleted, duplicate post.

 

[lakeroadster]

Staging A10 motors rock!
View attachment 636756
Use 12 motors per flight. If one happens to CATO, no problem, just gets one stack out of sequence.

Using Estes ignitors no less.​

 

[Daddyisabar]

Using Estes ignitors no less.​

The supply of old back heads is dwindling.

No starters!

Q2G2s are like gold.

Yes Mr. RSO, it's just an ignition issue.

 

[lr64]

When I see those little fins up front, I just want to connect them to servos and one of those RC stabilizer gadgets. RC not necessary, though. One could just provide a steady pulse from an electronic gadget in the rocket itself.

As long as we've got the fins, if it weren't for the FAA, one could make the thing dive back down to the general vicinity of the launch before deploying the chute.

 

[lakeroadster]

When I see those little fins up front, I just want to connect them to servos and one of those RC stabilizer gadgets. RC not necessary, though. One could just provide a steady pulse from an electronic gadget in the rocket itself.

As long as we've got the fins, if it weren't for the FAA, one could make the thing dive back down to the general vicinity of the launch before deploying the chute.

They're "Spin Tabs".​

Their purpose is to spin the rocket, specifically after the motor thrust stops. GDS stops once the thrust stops, so the spin tabs ensure stability since there are no lower fins for the 2nd, 3rd and 4th stages.​

 

[lakeroadster]

Staging A10 motors rock!
View attachment 636756
Use 12 motors per flight. If one happens to CATO, no problem, just gets one stack out of sequence.

That looks vaguely similar to the rocket on post #3. ​

 

[lr64]

They're "Spin Tabs".​

Their purpose is to spin the rocket, specifically after the motor thrust stops. GDS stops once the thrust stops, so the spin tabs ensure stability since there are no lower fins for the 2nd, 3rd and 4th stages.​

I know, but that doesn't stop me from thinking of using them another way.

 

[lakeroadster]

I know, but that doesn't stop me from thinking of using them another way.

Have at it!​

 

[DirkTheDaring]

I second the desire for Estes to make the C5-0. Up there with the D12 with the best max lift : weight ratio of all the Estes engines (9.6:1).

C11-0 is only listed as 170g max lift. That is going to be close even with 4x 18mm engines. Maybe D12-0 in lowest and C11-0 next.

D12-0 + C11-0 + C6-0 + B6-0 + B6-6

Actually fits into the Highschool thing if you do something like this (how many people had E's instead of F's in their schools)...

E12-0 + D12-0 + C6-0 + B6-0 + A3-6

Sign my petition to bring out a C5-0!!!
https://chng.it/BLHgytn4kY