Black rock project 2 stage 2018 min diameter

sweeeet!

Going the Altus Metrum route will be worth it. If you are doing it anywhat, may I suggest going for the full on TeleMega in the sustainer, with the Telemetrum in the booster. It is only an extra $100, and you will have the tracking built in too. You can track both units with the same reciever, and it shows both units on the Android map. Make sure you note the number of each, there may be other peoples units show on the map. You can then tell the app which of the units to use as primary for telemetry.
I am going this way, and will be using the RRC3's as backup. The extra channel can be programmed to do a separation charge for the booster unit.
They are real neat units and worth every $$$

Salvage-1 said:

sweeeet!

Going the Altus Metrum route will be worth it. If you are doing it anywhat, may I suggest going for the full on TeleMega in the sustainer, with the Telemetrum in the booster. It is only an extra $100, and you will have the tracking built in too. You can track both units with the same reciever, and it shows both units on the Android map. Make sure you note the number of each, there may be other peoples units show on the map. You can then tell the app which of the units to use as primary for telemetry.
I am going this way, and will be using the RRC3's as backup. The extra channel can be programmed to do a separation charge for the booster unit.
They are real neat units and worth every $$$

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That is a great suggestion. I already have the RTX for the nose cone in the sustianer. The ebay in the sustainer is Carbon.

ColumbiaNX01 said:

After booster motor burn out a small separation charge will go off to separate the stages. Then the sustainer will continue to coast before the sustainer is lit by the aux event in the sustainer ebay. Does that make any sense?? The idea is to protect the booster from the sustainers ignition. Go for maximum altitude.

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You should do the calculation to see if the sustainer would be in a drag separation mode at motor burnout. It probably is unless the mass of the spent booster is still larger than the unfired sustainer. If the rocket is not in drag separation mode (interstage coupler in compression) then separating the booster at motor burnout will cost you altitude.

What is the calculation?

Fsep = a [ M / (1+R) - M1 ]

Where:
a = max deceleration
M = total mass of rocket (mass NOT weight)
M1 = mass of lower section
R = drag ratio

If Fsep is +, then there is a drag separation force, if - then there isn't.

ColumbiaNX01 said:

What is the calculation?

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An easy way to do this is just to perform a simulation and look at the acceleration values. Set it up so that is a delay of one second before separating the booster and then another delay of one second before lighting the sustainer. At the point where the booster separate, if the acceleration goes up (becomes less negative) there is a tendency for separation, and vice versa. Most of my two-stagers want to separate, but there isn't much net force. Therefore, I use a small charge in any case.

Jim

JimJarvis50 said:

An easy way to do this is just to perform a simulation and look at the acceleration values. Set it up so that is a delay of one second before separating the booster and then another delay of one second before lighting the sustainer. At the point where the booster separate, if the acceleration goes up (becomes less negative) there is a tendency for separation, and vice versa. Most of my two-stagers want to separate, but there isn't much net force. Therefore, I use a small charge in any case.

Jim

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That is easier, thanks.

This will fly in to different flights At Airfest. The booster with the payload on top on a M1850. Then they sustainer will fly with the payload on a J800. Then later at another launch it will fly in 2 stage config on a K1000 to a J350.

ColumbiaNX01 said:

This will fly in to different flights At Airfest. The booster with the payload on top on a M1850. Then they sustainer will fly with the payload on a J800. Then later at another launch it will fly in 2 stage config on a K1000 to a J350.

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Awesome , can't wait to see them!

That is beautiful

So at Airfest 2017 I launched my rocket in single configuration. I launched the sustainer on a Aerotech K800T and flawless flight to 5,260 feet. Then I launched the booster with the payload on a Aerotech M1850W and it went just north of 25K. Great staright boost but the booster zippered about 3 inches down.

I will fly this rocket in 2 stage config at High Frontier 2017 at the end of the month on a Aerotech K1000W staging to a Aerotech J350W. RasAero sims to around 12K.

Well the rocket has been fixed. It will fly at High Frontier 14 in Pawhuska, Oklahoma. At the airport. I will fly it on a K1000T and stage to J460T. Anticipated over 12K

Was it an energetic deployment that caused the Kevlar to rib the Carbon tube?

Nytrunner said:

Was it an energetic deployment that caused the Kevlar to rib the Carbon tube?

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Thats what I think. Only option in my book. I am sticking to that event no pun intended. lol

Hopefully future events won't stick it to you! Lol

Nytrunner said:

Hopefully future events won't stick it to you! Lol

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Well with the 2 stage this weekend I will put the perfect amount wont over due it.

Nytrunner said:

Was it an energetic deployment that caused the Kevlar to rib the Carbon tube?

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I've shot lots and lots of video of rockets over the years including a pretty decent number of deployments that resulted in zippers. In my experience of viewing many of these events, zippers are caused by only one thing - the rocket is moving at a higher than intended rate of speed when the parachute fills. This is caused typically by one of three things:

* a large horizontal velocity caused by weathercocking or large arc at apogee

* a recovery harness that is too long and allows the fincan to pick up speed after separation and after the parachute fills but before it reaches the end of the harness

* mistimed recovery deployment - drag separation, early or late motor ejection, or altimeter error

I can't recall a single zipper caused by an energetic deployment. Think about it - at deployment the fincan and upper section are being separated directly opposite from each other at deployment and the chute has not yet filled, how could that cause a zipper? What I've seen happen from overly energetic deployments is popping the main at apogee during a dual deploy (by causing the main chute to slam forward against the nosecone) or causing a recovery system failure at its weakest point, like a cheap D-ring, an open eye hook, or something similar.

So from everything that I've seen zippers are caused because the booster/fincan is traveling at a high rate of speed away from the filling parachute, not from an energetic deployment. It's all about speed of the components when the chute fills.

I've done some analysis of altimeter data to look at speed of components when the main chute fills. A lot depends on the altimeter(s) you are using. But if you have an accelerometer based altimeter you'll be able to look at the plot and see that the ejection charge and the large forces felt during a zipper are usually separated by a measurable amount of time. And in some cases you can estimate the horizontal velocity which will tell you a lot.


Tony

Successful launch!! K1000 to J460. Flawless. Used a Pyro pellet and dipped E match to light sustainer. RRC3 worked fantastic. It drag sperated perfectly. Have to look at the electronics to see exact altitude.

Outstanding...keep at it.
Looks like you're ready for the full stack!

Looks like you're a year ahead of Black Rock '18.

What's the flight load for that then? M-M?

Nytrunner said:

Looks like you're a year ahead of Black Rock '18.

What's the flight load for that then? M-M?

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Full stack will be M1850 to L1090.

I may build just a new booster so that I will have room for dual deploy using cable cutter. It is a 48 inch booster if I build a 52 inch booster I will be able to do cable cutter. The way it was today was so so tight. Only had room for a 36 inch top flight. Came down to fast for my liking. Because of the cramped space I just had the main come out at apogee. Plus, today the RF transmitter is stuffed in there I dont want to break the antenna. Well the antenna was fine but......dont like it.

None the less today was succesfull. Its a learning process. Every time I launch a rocket I learn what to do better the next time. I love those printed modular sleds. They make the electronic bays piece of cake.

Flight data is in:


The booster flew to 4,062 feet when the event occured.

The sustainer flew to 9,369 feet at 761 f/s .67 mach