Multi Stage Saturn V

lakeroadster

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This rocket has (4) D12's firing off ejection charges 3 seconds after the fuse lights to fire the 2nd stage motors.

Do you folks think it would be prudent to build a piston to push out the parachute... or is that not needed?

SHould I add a piston.jpg
 

boatgeek

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This rocket has (4) D12's firing off ejection charges 3 seconds after the fuse lights to fire the 2nd stage motors.

Do you folks think it would be prudent to build a piston to push out the parachute... or is that not needed?

View attachment 549792
I wouldn't bother unless you're worried about protecting the chute. A piston is more weight in the wrong end. Even for chute protection I'd just go with generous dog barf above and below.
 

Daddyisabar

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I wouldn't bother unless you're worried about protecting the chute. A piston is more weight in the wrong end. Even for chute protection I'd just go with generous dog barf above and below.
Maybe even a yummy dog barf and wadding sandwich on top. The Dangerwich! Better watch out...it's spicy! LET'S RIDE! A successful launch will quell the misery of all those Broncos fans in Lakeroadster's neck of the woods. :)

KISS!
 

Daddyisabar

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Are you using traditional or flash pan for the fist stage...don't remember if it was mentioned before. Spider Flash pan would be awesome (scale points) and a cluster box for traditional ignition to greater insure they all light immediately.

5 D12s gives you an F60 on take off. Enough to stage properly given the weight, drag and timing. I guess you have to trust the Machines. I've launched a B58 on six D12s at Hartsel and I was ok on the second try. Confidence is key! Fear is the mind killer. I don't need another rocket scientist, I need a good electrician! :)
 

jqavins

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Gee, I hadn't thought about chute protection on top. For protection on the bottom, if you wand more than dog barf and/or paper wadding, I'd use a baffle rather than a piston, since it doesn't add any moving parts. As for the top, I'd want a nomex sheet, now that @Daddyisabar has mentioned it.

And he has a good point about the cluster box too.
 
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lakeroadster

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@Daddyisabar , @boatgeek , @jqavins

The only reason I thought piston was I've read probably 30 threads here on TRF where folks make a point about "The ejection charge doesn't push the chute out. It pops off the nose cone, and the nose cone drags the chute out".

Since this is a stage and thus has no nose cone, I figured with a piston... the chute has no alternative but to exit the fuselage. :dontknow:
 

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@Daddyisabar , @boatgeek , @jqavins

The only reason I thought piston was I've read probably 30 threads here on TRF where folks make a point about "The ejection charge doesn't push the chute out. It pops off the nose cone, and the nose cone drags the chute out".

Since this is a stage and thus has no nose cone, I figured with a piston... the chute has no alternative but to exit the fuselage. :dontknow:
Chute-cannon. Staging is already complete so there is nothing to pull the parachutes out. Next option I can think of is a smaller tube above 2 motors on one side replicated over 2 motors on the other side. In that smaller tube is housed your parachute. It could have a fixed "piston" like PML employs or a baffle system but I'd recommend a few layers of tissue based wadding followed by dogbarf and parachute on top. This could be replaced with nomex but in this case I'd recommend not. I normally refer to this as a soft piston or a LP chute-cannon.
 

boatgeek

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@Daddyisabar , @boatgeek , @jqavins

The only reason I thought piston was I've read probably 30 threads here on TRF where folks make a point about "The ejection charge doesn't push the chute out. It pops off the nose cone, and the nose cone drags the chute out".

Since this is a stage and thus has no nose cone, I figured with a piston... the chute has no alternative but to exit the fuselage. :dontknow:
I think there may be some truth to that statement in large HPR projects or cases where the ejection charge is between the airframe break and the parachute (eg HED and drogues in "normal" dual deploy setups).

In this case, I have a really hard believing that 4 ejection charges aren't going to blow that chute out just fine. You're not using a ramrod to set it into place after all. Thinking it over, I'd worry more about a donut piston jamming up when one of the side motor ejection charges fire a fraction of a second before the others.
 

jqavins

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The only reason I thought piston was I've read probably 30 threads here on TRF where folks make a point about "The ejection charge doesn't push the chute out. It pops off the nose cone, and the nose cone drags the chute out".
I've read some of those (not 30) too, and for every one I've read two or more that say the chute must be pushed out, not pulled. Popping the nose so that it pulls the chute would require ejection gas to bypass the chute on its way to the nose cone. If I were counting on that, I'd want the chute in a nomex bag (which I'm given to understand is not uncommon in the larger HP designs).

Thinking it over, I'd worry more about a donut piston jamming up when one of the side motor ejection charges fire a fraction of a second before the others.
And thus my preference for a baffle. (Well, that among other possible problems that potentially result from unnecessary moving parts).
 

boatgeek

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I've read some of those (not 30) too, and for every one I've read two or more that say the chute must be pushed out, not pulled. Popping the nose so that it pulls the chute would require ejection gas to bypass the chute on its way to the nose cone. If I were counting on that, I'd want the chute in a nomex bag (which I'm given to understand is not uncommon in the larger HP designs).


And thus my preference for a baffle. (Well, that among other possible problems that potentially result from unnecessary moving parts).
I'm going to go out on a limb and say that it's an area of disagreement because it's an area where several physical models make some amount of sense and it's really hard to actually analyze/see what's really happening. An ejection charge test with a clear airframe might do it.

A toroidal baffle is probably the easiest way since you could do the job with alternating 60%-depth centering rings.
 

lakeroadster

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I think there may be some truth to that statement in large HPR projects or cases where the ejection charge is between the airframe break and the parachute (eg HED and drogues in "normal" dual deploy setups).

In this case, I have a really hard believing that 4 ejection charges aren't going to blow that chute out just fine. You're not using a ramrod to set it into place after all. Thinking it over, I'd worry more about a donut piston jamming up when one of the side motor ejection charges fire a fraction of a second before the others.
The piston would have a hole through it's center, so it would ride up the center fuse conduit tube.... but I'm thinking I'll just abandon the piston idea, and load it up with dog barf, above the chute and below the chute.

Thanks for your input fella's.
 
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Daddyisabar

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How I envision this rocket.....

View attachment 550044
____________________________________________________________________________________________________________________

How the non rocketeer world envisions this rocket....

View attachment 550050
Envision it going straight up, no angle at staging!

Will the kid with the cookie or Lakeroadster have the easiest time getting by the RSO table! :)
I like cookies!
 
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Daddyisabar

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The third stage chute is forward deployed by the third stage booster motor?

Nothing "popping out" for base drag? Just the tube diameter.

The adequate sablizing spin is imparted and continues by canted fins on the first stage, immediately on and just off the rod until staging?

Sorry for all the questions.

More like Tweedle Dee and Tweedle Dum. :)
 

lakeroadster

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The third stage chute is forward deployed by the third stage booster motor?

When the 4th stage A or 1/2A motor ignites the 4th stage has a Kevlar chord that pulls the parachute out of the 3rd stage for the 3rd and 4th stages.

Nothing "popping out" for base drag? Just the tube diameter.

The simulation shows the 4th stage is stable, due to base drag. And the data output shows the 4th stage is indeed spinning.

The goal is to just get the 4th stage to ignite and deploy the chute or streamer. If the 4th stage is indeed unstable, no worries.

4th Stage Open Rocket Stability.jpg

The adequate stabilizing spin is imparted and continues by canted fins on the first stage, immediately on and just off the rod until staging?

That's the mindsim, and the Open Rocket data output shows the rocket spinning throughout it's flight. You can see in the screen shot below how the roll rate of 39.850 rev's per second (2,391 RPM's) stops increasing when the 1st stage separates from the 2nd stage.

2022-12-10 Saturn V Data Export Roll Rate.jpg
 

lakeroadster

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I spent the better part of the day refining the Open Rocket simulation, trying my best to get the data as accurate as possible using the calculated CAD model weights, and working through weird Open Rocket flight plots that lead me to correct incorrect data inputs.

The more I use this software... the more I come to respect the folks that developed it, and those working to refine it.

I couldn't understand why the plots were being cut off across the top? :dontknow: The issue was the 3rd stage actually apogee's higher than the 4th stage... because the 3rd stage is significantly heavier and coasts more. Open Rocket naturally assumes the highest flying part will be the 4th stage, so it uses that apogee to establish the Y axis.

2022-12-10 OR Flight Sim Saturn V 1-132 Scale 4 Stage Model Rocket.jpg

2022-12-10 OR Flight Sim Saturn V 1-132 Scale 4 Stage Model Rocket - Plot.jpg
 

BABAR

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This may be your most impressive engineering endeavor ever, which is saying a lot!

one issue I potentially see with roll stability. Just like a potter’s wheel with the first lump of clay off center, or some washing machines that start wandering around the laundry room with a heavy off center lump of clothing, a concern you will have with spin stability, ESPECIALLY imparted spin stability (where the spin starts with canted fins on one stage and is ASSUMED to continue slowing only to surface drag on subsequent stages) is rocket packing. With those rear eject chutes on the OUTSIDE of the motor mounts, it may not take much “wobble” to cause a much more rapid loss of spin than projected. The mass off your monolithic nose cone is presumably evenly distributed, and may be such that any asymmetries from the other parts would be negligible. Then again, depends on how fast this puppy spins.

as for the last stage not being stable, but doesn’t matter, I agree. Assuming it is at any decent altitude, if it is stable it is stable, if it is UNSTABLE, since it has no fins, I doubt the imparted rocket motor thrust is going to MAKE it become stable, so it will likely do some entertaining skywriting and then burn out, hopefully popping the chute before touchdown. This was one of my beefs with Estes MIRV (the primary beef being they had no business releasing it until they had an 18 mm zero delay motor capable of lifting that stack! if/when the C5-0 comes out they should re-release it.). In any case, the MIRV sustainers were two finned rockets and were NOT stable, though again no big deal as they would stage high and just skywrite.

hope you get let’s see…..five……ten……oh heck, lots of straight trails!
 

lakeroadster

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This may be your most impressive engineering endeavor ever, which is saying a lot!

one issue I potentially see with roll stability. Just like a potter’s wheel with the first lump of clay off center, or some washing machines that start wandering around the laundry room with a heavy off center lump of clothing, a concern you will have with spin stability, ESPECIALLY imparted spin stability (where the spin starts with canted fins on one stage and is ASSUMED to continue slowing only to surface drag on subsequent stages) is rocket packing. With those rear eject chutes on the OUTSIDE of the motor mounts, it may not take much “wobble” to cause a much more rapid loss of spin than projected. The mass off your monolithic nose cone is presumably evenly distributed, and may be such that any asymmetries from the other parts would be negligible. Then again, depends on how fast this puppy spins.

as for the last stage not being stable, but doesn’t matter, I agree. Assuming it is at any decent altitude, if it is stable it is stable, if it is UNSTABLE, since it has no fins, I doubt the imparted rocket motor thrust is going to MAKE it become stable, so it will likely do some entertaining skywriting and then burn out, hopefully popping the chute before touchdown. This was one of my beefs with Estes MIRV (the primary beef being they had no business releasing it until they had an 18 mm zero delay motor capable of lifting that stack! if/when the C5-0 comes out they should re-release it.). In any case, the MIRV sustainers were two finned rockets and were NOT stable, though again no big deal as they would stage high and just skywrite.

hope you get let’s see…..five……ten……oh heck, lots of straight trails!
My THUNK! GDS rocket used spin stabilization with (6) really small spin tabs (aka fins). It worked great, you can actually see the corkscrew engine exhaust trail.

My mindsim says this should spin up to a decent RPM really quick. It doesn't have big fins that create a lot of rotational drag, no fins at all on stages 2-4. Open Rocket shows an RPM of nearly 2,400 RPM. :shocked: While I don't think that high of an rpm is realistic, this rocket really doesn't need much. It takes advantage of base drag, and every stage, on it's own, is a stable bird.

Also keep in mind that the 3rd and 4th stages are woefully underpowered and aren't under thrust for very long at all, in an attempt to maintain a fairly low apogee to increase the odds of recovering all 4 stages. Stage 3 and 4 Mylar streamers deploy at around 750 feet.

This rocket apogee's at nearly 3,000 feet if implemented with Estes E12 24mm motors in all the stages .... but then the likelihood of finding all the stages would not be realistic, at least where we launch that's the case. But that would require an L1 certification and I'm really not into launching anything that seems non-recoverable.
 

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The fact that you have a third stage coasting higher than the powered fourth stage is... impressively weird. 🤓
So the third stage is stable even after the fourth deploys? (I would think with a now blunt nose if not a gaping hole it would start tumbling (still upwards as until drag and gravity overcome kinetic energy, which would be considerable.). If indeed it is stable, would make an interesting camera or cameraS View (one on each side to increase odds of catching it) looking DOWN from stage three and watching it overtake stage 4.

an interesting byproduct of combination of base drag and spin stabilization, should (I theeeeeenk) be more resistant to weathercocking than typical staged low power birds.

i have really enjoyed using a cluster on first stage rockets with a zero delay standard booster motor to light the sustainer (or in your case the next stage), and a short delay auxiliary to pop the chute on the booster. The delay works nicely to let the booster slow down a bit before chute deployment.

for some reason I intuitively (and of course wrongly) think that at staging the booster should immediately stop and start falling, I guess the “push-off” of the lighted sustainer (for standard gap or non-gap black powder staging there is NO delay for an air start of the sustainer, if they separate before the sustainer lights the sustainer becomes a purely ballistic object), anyhoo, the “push off” from the sustainer apparently doesn’t slow the booster down that much. NON-gap booster stages are usually incredibly unstable so they start tumbling immediately.

how big a group do you fly with? You’ll need designated spotters to track each stage if you hope for a second flight.
 

lakeroadster

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The fact that you have a third stage coasting higher than the powered fourth stage is... impressively weird. 🤓
That's my creedo... "Impressively weird".​
It took a bit of head scratching to figure out what was going on when viewing the plot. This is when I learned that when viewing an Open Rocket Plot, you can "left click" on the curve to identify it... which on a multi stage rocket helps a lot.​

So the third stage is stable even after the fourth deploys? (I would think with a now blunt nose if not a gaping hole it would start tumbling (still upwards as until drag and gravity overcome kinetic energy, which would be considerable.).

The 3rd stage has the 1.88" dia. to 3" dia. redwood transition at it's base, so that's a lot of base drag. But at the 3rd to 4th Stage separation the 3rd Stage streamer deploys, so in reality, no it won't be stable. It will however have considerable momentum and will likely be coasting to it's apogee backwards.​
The lower the stage apogee the better in regard to increasing the chance of recovery. That's why I'm using Mylar streamers... glittering visibility.​

an interesting byproduct of combination of base drag and spin stabilization, should (I theeeeeenk) be more resistant to weathercocking than typical staged low power birds.

Agreed. As previously discussed, THUNK! was stable, but it did weathercock some. But then, even a spinning bullet moves due to "windage". Some of THUNK!'s "nose-to-the-wind tendency I think was from an out-of-balance wobble. I need a spin balancer... lol.​

how big a group do you fly with? You’ll need designated spotters to track each stage if you hope for a second flight.

Just me and the lovely and talented Mrs. Lakeroadster. However, she's giving signs of bailing on future flights, justifiably I should say. My F-79 lawn dart and the cartwheeling Mercury LES has her questioning the sanity of being associated with some of my rocket "flight profiles". She's a trooper.​
I may have to bribe @Daddyisabar to join me, or perhaps load the truck up and head to Dove Valley where he and some of his crew burn black powder.​
Recovery Crew.JPG
 
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BABAR

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Still thinking through your first to second stage issue. Outside the box solution which I think has a high success probability, but without a 3D printer would be challenging.

manifold gap staging.

your first stage has five motors, at least one (and preferably two, for redundancy) are delay motors which, after the zero delay motors initiate staging (we’ll get to that ) allow the booster to slow a bit before popping chutes.


leaves you three zero delay motors to ignite five second stage motors.

manifold connects three zero delay motors to a SINGLE tube which then splits to five tubes.

each of the five tubes has it’s own vent.

the Gryphon I think was one motor to 3, and I think @GlenP (please correct me if I am wrong) has done one motor to 4.

I have gapped one to one over 50 inches, so the volume really isn’t an issue.

my two rockets 1 to 3 were both successful (only did a few flights, but they all worked 100%.). I did a hack job of mating a single 24 mm mount tube to three 18 mm mounts, just with paper tubes and glue, I may have smeared some glue on the middle section that got the brunt of the booster flame for protection, it’s been a while.

also gives you some redundancy, I think any single C6-0 will probably light all 5 second stage motors, two or three going off near simultaneously should do it.

without a 3D printer, a 3 to 5 manifold would be a real PITB to handcraft. I don’t know squat about 3D printing, but I suspect would be do-able (maybe @cwbullet would know). Also not sure how much it would weigh.

have you simmed this with B6-0s in the first stage? has same max lift off weight as the C6. Shorter burn may reduce your canted fin terminal RPM rate, not sure that matters. Should get you off the rod the same as C6 (maybe a bit better, as it shaves off a few grams.). Of course, might stage 10 feet off the ground, but that would be safe, exciting, and reduce weather cocking.
 
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