Lakeroadster's "High School Confidential"

[lakeroadster]

A Bit of Background

Back when I was in High School (1976 ish) I made a rocket using a Christmas wrapping paper cardboard tube that had 4 or 5 (I can't recall which) D12 motors. It was just a nose cone, a parachute and the 5 motors glued into the cardboard tube. This was meant to be a one launch and done rocket.​

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My thought was when the rocket staged the motor would burn through the cardboard and the lower motor and it's severed cardboard wrapping paper BT would tumble back to earth, rinse and repeat 3X.​

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Me and my friend Tracy launched it in Dad's 5-acre hay field that we had just bailed. I drove our trusty 1965 Cub Cadet out into the middle of the field and we set-up the Estes 3 legged orange launch pad.​

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5-4-3-2-1 launch.​

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The 5th stage fired the 4th stage at maybe 20 feet in the air. The rocket then went horizontal and started doing a flat spin. The next 2 stages basically followed suit. The rocket ground hit about 10 feet from the launch pad, where the last 2 stages finished their burn and the ejection charge popped the chute out on the ground.​

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The launch site was filled with BP smoke as you could well imagine. When we did the postmortem on the rocket, all the stages were still intact in the cardboard tube, but there were large holes where the D motor exhaust had pierced through the side wall of the cardboard tube. Picking up the rocket it had kind of turned into a 5 segment Slinky.​

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Fast Forward 46 Years

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.

Motors will all be friction fit. When using 18mm motors the plan is to use the Estes plastic 24mm to 18mm adapters.

1/8" basswood fins, surface mounted (with wood glue rivets and big glue fillets) for the tumble recovered boosters, 1/8" basswood utilizing front halfed TTW fins for the sustainer.

I'm thinking the flight using (3) A8 motor's and a C6 motor should be pretty awesome. Any motors bigger than that will likely be lost to The Gods of Vertical Thrust.

 

[mikewrt]

Good luck! Congrats on developing a new teleportation device. Wish you 2 or 3 or 4 straight trails and less than 5 square mile recovery assuming it doesn't vanish into the space time continuum.

 

[Daddyisabar]

Cheap and dirty staged clusters need to be in seperate vertical stacks. Traditional, horizontal stages will not work (unless you are NASA). Think of bundling 4 seperate staged rockets together. Or Bind four rack rockets together. Or go with seperate tractor motor stacks. FEEL THE BURN!

 

[Daddyisabar]

All of your burn times have to be in sinc!

 

[BigMacDaddy]

D12 is one of the few motors that can lift 5 of itself + a rocket...

I am skeptical that the C6-0 can lift 4x C engines + rocket. Max lift is listed as 113g and weight is 22.7+22.7+22.7+26.9+rocket...

 

[lakeroadster]

Cheap and dirty staged clusters need to be in seperate vertical stacks. Traditional, horizontal stages will not work (unless you are NASA). Think of bundling 4 seperate staged rockets together. Or Bind four rack rockets together. Or go with seperate tractor motor stacks. FEEL THE BURN!
View attachment 530106

That's cool! But for this rocket I'm trying to replicate something I did almost 50 years ago.

 

[Daddyisabar]

Computerized sim, garbage in, garbage out. Mindsim..."Oh No...Hell No!" There are ways to relive your past dreams but you must give in and realize the true power of the Dark Side!

 

[Daddyisabar]

That's cool! But for this rocket I'm trying to replicate something I did almost 50 years ago.

That is easy. Build and purposely crash/land snake. Just like the crash for TV shows like Rocket City Rednecks and the flying snowmobile and garden pig. Not something you will learn from the NAR Jedi. Simple run, duck and cover.

Why not try to make it work? Make new dreams come true.

 

[lakeroadster]

That is easy. Build and purposely crash/land snake. Just like the crash for TV shows like Rocket City Rednecks and the flying snowmobile and garden pig. Not something you will learn from the NAR Jedi. Simple run, duck and cover.

Why not try to make it work? Make new dreams come true.

So you don't think the 4 stager will work?

 

[Daddyisabar]

So you don't think the 4 stager will work?

In other similar threads (as yours is configured) the rocket scientists did the math on a cluster successfully CHAD staging another cluster and so on. It got real bad even after successful ignition of the first stage cluster. Being dedicated to science I do not question the math, so I think you are looking at a snow balls chance in Hades.

Embrace the Dark Arts of independent stacks of CHAD staging fun and you will begin on the right path. The first question, depending on the look you are going for, is TRACTOR (easy but very hot) or traditional pusher motors on the bottom (harder, lots of falling bits requiring large ground crew to watch and recover. )

 

[BigMacDaddy]

Which configuration is that in the simulation you shared? That must be one of the lighter ones -- like the C engine mix (I edited my comment above -- I am skeptical that the first C6-0 will lift that rocket).

Personally I would increase fin surface area and sweep them back as well as elongate the rocket to help push CG forward without too much nose weight. Even this config of D12-0 + D12-0 + C6-0 + C6-0 + B6-6 is only going 16m/s off the rod (it gets heavy with all those motors). The 3rd C6-0 is probably a bit weak but the rocket should already be moving.

Bonus this one looks like an arrow...

 

[Daddyisabar]

I see now you are not clustering stages (I misread the sim as I don't use them and thought you were attempting something really cool) Then for a simple 4 stage build extremely light, no stinking bass wood, and if a D12 0 can lift it an keep straight on a calm day you should be ok.

 

[Daddyisabar]

I see now you are not clustering stages. Then build extremely light, no stinking bass wood, and if a D12 0 can lift it an keep straight on a calm day you should be ok.

Which configuration is that in the simulation you shared? That must be one of the lighter ones -- like the C engine mix (I edited my comment above -- I am skeptical that the first C6-0 will lift that rocket).

Personally I would increase fin surface area and sweep them back as well as elongate the rocket to help push CG forward without too much nose weight. Even this config of D12-0 + D12-0 + C6-0 + C6-0 + B6-6 is only going 16m/s off the rod (it gets heavy with all those motors). The 3rd C6-0 is probably a bit weak but the rocket should already be moving.

Bonus this one looks like an arrow...

View attachment 530124

Do this one.

 

[Daddyisabar]

Take and bundle three or four of the rockets above together for a College confidential. Getting late, time for bed.

 

[BABAR]

I like it! however, while C6-0 has MAX lift off weight of 4 oz, this is a draggy rocket heavily prone to weather cocking. You need to get this off the rail with authority.

https://estesrockets.com/wp-content/uploads/Educator/Estes_Engine_Chart.pdf

sure wish they would release that C5-0. In any case, I’d go with at least a C11-0 if not a D12-0 on the lowest stage. Then A8-0, A8-0, and A8-5.


also put at least a small lug or button on the sustainer, otherwise there is a strong lever arm with just a lug on lowest stage, even light winds blowing across the body tube can break off the lug or buttons on the lowest stage.

long streamer on the sustainer, the extra length beyond 10-1 won’t slow it down but will make it much more visible.

 

[BigMacDaddy]

sure wish they would release that C5-0. In any case, I’d go with at least a C11-0 if not a D12-0 on the lowest stage. Then A8-0, A8-0, and A8-5.

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

 

[lakeroadster]

Which configuration is that in the simulation you shared? That must be one of the lighter ones -- like the C engine mix (I edited my comment above -- I am skeptical that the first C6-0 will lift that rocket).

Personally I would increase fin surface area and sweep them back as well as elongate the rocket to help push CG forward without too much nose weight. Even this config of D12-0 + D12-0 + C6-0 + C6-0 + B6-6 is only going 16m/s off the rod (it gets heavy with all those motors). The 3rd C6-0 is probably a bit weak but the rocket should already be moving.

Bonus this one looks like an arrow...

View attachment 530124

Way, way, way too much fin... think weathercocking.​

I like it! however, while C6-0 has MAX lift off weight of 4 oz, this is a draggy rocket heavily prone to weather cocking. You need to get this off the rail with authority.

https://estesrockets.com/wp-content/uploads/Educator/Estes_Engine_Chart.pdf

sure wish they would release that C5-0. In any case, I’d go with at least a C11-0 if not a D12-0 on the lowest stage. Then A8-0, A8-0, and A8-5.


also put at least a small lug or button on the sustainer, otherwise there is a strong lever arm with just a lug on lowest stage, even light winds blowing across the body tube can break off the lug or buttons on the lowest stage.

long streamer on the sustainer, the extra length beyond 10-1 won’t slow it down but will make it much more visible.

Fella's.. I love all the comments!​

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In an attempt to combat weathercocking, by reducing fin size... why not build upon what I learned with THUNK! and add GDS ports to this bird and eliminate most of the fins altogether?​

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Here's a 4 stage silo launched design that uses traditional fins for the first stage, and GDS for the next 3 stages.​

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Take the Estes max launch weight and disregard it, except for the initial booster. The rocket is already moving for all the other stages, the rocket therefore already has momentum.​

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I'm kind of stoked about this design. Super easy to build and should be a spectacular flight. Design still needs some tweaking, but you get the idea.​

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The initial stage 1 booster just tumbles at stage separation and has no body tube at all, this occurs at about 170 feet​

Stage 2 has fins and GDS, occurs at about 500 feet​

Stages 3 is GDS, occurs at about 625 feet​

Stage 4 is GDS and apogee is at about 875 feet, recovery via streamer​

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Maiden flight could be a 2 stage. Then a 3 stage, then 4.​

 

[techrat]

I don't think that first stage is going to be able to lift that much weight off the pad. If you're exceedingly lucky, it'll get only a few feet off the ground before the first stage expires.

Has anyone built a multi-stager that uses an E for the first stage, D for the second stage and C for the third?? This way the rocket is more like a real multi-stager in that each lower stage is more powerful, and as stages drop away, the rocket has to do less work to keep going.....

 

[BigMacDaddy]

Haha -- I guess I only launch when there is no wind...

Interesting idea using GDS. I would think that GDS would not work [as well?] with minimum diameter -- engine would burn the bottom portion of tube and no space to draw in outside air. Might require a engine tube inside a larger outside tube. Also, GDS seems to have more "wiggle" or "wobble" which might be compounded across multiple stages.

 

[BABAR]

. Super easy to build and should be a spectacular flight. .​

Almost certainly a true statement.

“Spectacular” does not always mean “good”, especially with staged rockets.

Suggest you build a two stage version first to prove the concept before going whole hog.

I was witness to an absolutely SPECTACULAR Cato on a staged rocket with @Ronz Rocketz and @kuririn in Hawaii, no harm, no foul, but I would not want to intentionally repeat it.

Suggest you start with two stages, the booster and sustainer, you can always build the remaining stages later.


Addendum, I just read your post in more detail, I see starting with two stages is the plan.

 

[lakeroadster]

I don't think that first stage is going to be able to lift that much weight off the pad. If you're exceedingly lucky, it'll get only a few feet off the ground before the first stage expires.

Estes shows max lift off weight for a D12-0 = 14 ounces

Open Rocket shows stage separation occurs at about 150 feet.

 

[lakeroadster]

Haha -- I guess I only launch when there is no wind...

Interesting idea using GDS. I would think that GDS would not work [as well?] with minimum diameter -- engine would burn the bottom portion of tube and no space to draw in outside air. Might require a engine tube inside a larger outside tube. Also, GDS seems to have more "wiggle" or "wobble" which might be compounded across multiple stages.

Are you familiar with the Ikaros Marine Parachute Flares? I used a couple sketches of this GDS design to determine the GDS openings on THUNK!.

I don't think a BT-50 (for this rocket) vs a BT-55 (like I used on THUNK!) is enough of a diameter difference to make difference. We'll see.

 

[lakeroadster]

Almost certainly a true statement.

“Spectacular” does not always mean “good”, especially with staged rockets.

"Blow or go, either way it'll be spectacular!" as stated by Carl Spackler Senior on May 5, 1937 just after the Hindenburg Ground Crew Safety Meeting

I was witness to an absolutely SPECTACULAR Cato on a staged rocket with @Ronz Rocketz and @kuririn in Hawaii, no harm, no foul, but I would not want to intentionally repeat it.

@BABAR - @Ronz Rocketz Was the issue just the motor cato itself, or was there some sort of structural failure?

This rocket should be very sturdy in regard to rigidity at the staging joints. A 24MM makes for a nice fit snug into a BT-55H, and with 1-3/8" engagement I can't imagine issues in that regard.

 

[lakeroadster]

I think I'll make some drawings of this version.

The simulation is a balancing act of keeping 4 stages, using lower power motors to keep the apogee reasonable, and keeping the 1st stage stable. The "all D12's" flight would be spectacular, but no way the sustainer would ever be recovered after the flight.

 

[Ronz Rocketz]

@BABAR - @Ronz Rocketz Was the issue just the motor cato itself, or was there some sort of structural failure?

There were a few Catos.

 

[BABAR]

"Blow or go, either way it'll be spectacular!" as stated by Carl Spackler Senior on May 5, 1937 just after the Hindenburg Ground Crew Safety Meeting



@BABAR - @Ronz Rocketz Was the issue just the motor cato itself, or was there some sort of structural failure?

This rocket should be very sturdy in regard to rigidity at the staging joints. A 24MM makes for a nice fit snug into a BT-55H, and with 1-3/8" engagement I can't imagine issues in that regard.

I think it was a Twin Factor with extra taped motors between booster and sustainer. I am sure Ron remembers it, I believe booster CATOed and despite all logic and physics somehow spontaneously lit other three motors. I hit the deck when the lit motors went in all directions, then after confirming nobody hurt and nothing on fire started LMBO.

 

[lakeroadster]

I think it was a Twin Factor with extra taped motors between booster and sustainer. I am sure Ron remembers it, I believe booster CATOed and despite all logic and physics somehow spontaneously lit other three motors. I hit the deck when the lit motors went in all directions, then after confirming nobody hurt and nothing on fire started LMBO.

Let's call this the "Thor's Hammer CATO".

I guess that makes sense. If the cato blows the propellant upward, with significant force, such that it would "clean house" so to speak then everything above it gets hammered out and ignited.

I bet Loki had something to do with it...

 

[BigMacDaddy]

Would love to see a staged GDS rocket so looking forward to this!!!

 

[BDB]

I LOVE the staged GDS design! Have you considered using a cluster of D12s in the first stage? If you really want to “Cheap and Dirty” it, what about gluing 2 or 3 motors to the central CHAD booster motor?

 

[lakeroadster]

Various Stages Viewed With Photo Studio

1st Stage: D12-0, 2nd and 3rd Stage: A8-0, Sustainer: A8-5

2nd Stage Occurs at 121 Ft. - 3rd Stage Occurs at 216 Ft. - 4th Stage Occurs at 313 Ft. - 4th Stage Burnout at 415 Ft. - Apogee at 704 Ft.

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