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Project Hi Lo Two Stage

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CORZERO

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Concept phase. Shooting for the 2 12 bet with my first LPR/MPR two-stage build. Basic two stage. F51 to F30. Paper and wood. I may vacuum a couple layers of carbon fiber on the fins for aesthetics.

Looking at this for a basic transition/coupler:

https://www.apogeerockets.com/Build...5-BT80?zenid=12f07af293e0b4092090cd69d7f26af2

And use this for sustainer ignition:

https://www.rocketarium.com/Accessories/MiniTimer4

Hi Lo.png

View attachment Hi-Lo.ork

Anyone out there have any experience with a similar project?
 
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watheyak

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I see two stages but no dart. Is the Rocksim file incomplete?
 

CORZERO

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I see two stages but no dart. Is the Rocksim file incomplete?
Wrong file, sorry. Working on several at a time. This is my pitch for a two stage F51 to F30 build. Any feedback would be great. Thanks!
 

BDB

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I watched the Apogee video about the clear transition the other day. It looks a little flimsy to me, but it is probably fine for the MPR build you are planning. I was thinking about trying to reinforce it with some FG since my 2-stage project is all FG construction. In the end, I opted to purchase a FG nosecone. I'll cut it and insert a coupler tube to make the transition/interstate coupler.
 

CORZERO

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In terms of strength it will be plenty strong, especially for my build, and perhaps even your build given an ideal launch. Looks can be deceiving. I am 5'10" and 200 pounds, yet if I balance myself properly, and distribute my weight evenly, I can stand on an empty Coke can without it collapsing. Look up monocoque design. How is your build progressing, by the way?
 

BABAR

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What is recovery plan for booster?
 

watheyak

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In terms of strength it will be plenty strong, especially for my build, and perhaps even your build given an ideal launch. Looks can be deceiving. I am 5'10" and 200 pounds, yet if I balance myself properly, and distribute my weight evenly, I can stand on an empty Coke can without it collapsing. Look up monocoque design. How is your build progressing, by the way?
Ever tried tapping the side of the coke can with your other foot while you're standing on it?

I understand monocoque design. But if a vac-formed transition is all there is, any off axis load is going to buckle that transition. You're going to need some internal structure there, especially if you're going to cut the top off. Sure, it's strong enough as an aerodynamic fairing, but not as a major load bearing component.
 
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BDB

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I'm planning for motor eject for my booster too, probably with a JLCR and an eggfinder built into an AV bay in the coupler to help me find it.
 

BABAR

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Is the booster going to have a chute or streamer?
Both the length and relatively small fin area may make flutter recovery suboptimal
 

CORZERO

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Is the booster going to have a chute or streamer?
Both the length and relatively small fin area may make flutter recovery suboptimal
I'm not familiar with flutter recovery. Booster recovery will be parachute, but I have yet to calculate descent rate for size. Booster fin root chord is 25% of total booster length.

OpenRocket calculates booster separation and second stage ignition at around 800 feet. I don't anticipate much drift for the booster. I don't have a problem visually tracking smaller vehicles to about 4,000 feet but I will install a tracker in the sustainer anyway as my launch site is surrounded by trees.
 

CORZERO

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Ever tried tapping the side of the coke can with your other foot while you're standing on it?

I understand monocoque design. But if a vac-formed transition is all there is, any off axis load is going to buckle that transition. You're going to need some internal structure there, especially if you're going to cut the top off. Sure, it's strong enough as an aerodynamic fairing, but not as a major load bearing component.
I am not going to add any internal structural reinforcement, nor will I cut the top off. I will be sure and post the flight results.
 

watheyak

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I am not going to add any internal structural reinforcement, nor will I cut the top off. I will be sure and post the flight results.
Ok, because your .ORK shows you're cutting the top off. Unless you intend to shove the motor way up into the sustainer, in which case you'll get no thrust from it.

Referencing your original post, I do have lots of experience with mid-power staging. Very similar to this, in fact. Why would you ask for help if you're just going to get defensive by saying "I'll be sure to post the flight results" when people offer suggestions?

I also find it odd that you'll add carbon fiber for aesthetics but stubbornly refuse to reinforce a super flimsy vac formed part.
 

CORZERO

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I apologize for being curt.

I am confident in the structural integrity of this particular unmodified plastic transition in this instance. The possibly destructive G loads on x and y (of which I have some mitigating control) that could do any harm to this model will cause other problems before the transition fails, in my opinion.

Also, good eye on the .ork! Although dimensionally accurate the .ork is a somewhat rough draft and is missing a part/value here and there (no lugs, motor retainer, etc.). The aft end of the sustainer motor mount tube will be flush with the aft-most centering ring. I will be using a CTI 24mm 3G case with my own retention device. The sustainer motor will be recessed approximately 1 inch, thereby causing little concern for Krushnic effect, as the air frame ID is 1.6 inches.
 

CORZERO

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54 to 38 with two J's. Any ideas how this happened?

[video=youtube;1VAkWgbCtA4]https://www.youtube.com/watch?v=1VAkWgbCtA4[/video]
 

dhbarr

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54 to 38 with two J's. Any ideas how this happened?

[video=youtube;1VAkWgbCtA4]https://www.youtube.com/watch?v=1VAkWgbCtA4[/video]
Slightly under stable for the rod/wind/thrust, no sustainer inhibit?
 

CORZERO

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Granted it was near horizontal when it did, the sustainer looked pretty stable once it lit so would that rule out over stable on the pad?
 

BDB

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Holy crap! That is scary!

I'm guessing the staging event was controlled by only timer. I suppose a RRC3 with a min altitude setting would have prevented the sustainer ignition, but that video might have just convinced me to invest in a Telemetrum.
 

Tinker

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but that video might have just convinced me to invest in a Telemetrum.
Or a launch bunker........

But it did just sell me on ponying up for more sustainer control.......

Good effort though.

Tinker
 

Tinker

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With your obvious skill with rockets and simulators, I doubt I could offer much more than a layman view. It seems like you started tipping over as soon as you cleared the rail and weren't going all that fast for what I would expect out of a J, especially given the thrust of the second engine. Its almost like your first stage weighed a ton or that first J did not perform as expected.

Tinker
 

CORZERO

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With your obvious skill with rockets and simulators, I doubt I could offer much more than a layman view. It seems like you started tipping over as soon as you cleared the rail and weren't going all that fast for what I would expect out of a J, especially given the thrust of the second engine. Its almost like your first stage weighed a ton or that first J did not perform as expected.

Tinker
The rocket in the video I posted was not mine.
 

CORZERO

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Tubes and slots cut:

20160915_164604.jpg20160915_165218.jpg

Fins cut by Nat at wingarcher@gmail.com. 3ply 1/8th inch birch. Perfect Nat quality as usual.


Mock up for scale:

20160915_170248.jpg

With the recent staging systems discussion I have decided that I will be staging this project with my Raven 3 and the appropriate failsafe settings. I'll build a mount for it which will fit in the nose cone and run igniter leads down the airframe, through the centering rings and out the aft end into the motor. I'll figure out a break-away method for the leads to separate upon ejection.

On another note, watheyak wins. I will also be reinforcing the flimsy plastic transition with CF after all as well as making other modifications to it.

watheyak, if you are watching, this is for you:

[video=youtube;8rwPovyR9HY]https://www.youtube.com/watch?v=8rwPovyR9HY[/video]
 
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blackjack2564

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54 to 38 with two J's. Any ideas how this happened?

Yes....booster was a research motor J-300 I believe. It was way under powered for a booster motor.
Rocket had flown before, it was fine.
Just not enough thrust in 1st stage when left rail...then motor kicked in after thing went south.

I was there, not pretty, but no one was hurt.
 
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