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Random Flying Object

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Alright, finally getting serious about getting this done for Airfest. This is a picture of the initial airframe layout.
ImageUploadedByRocketry Forum1402104383.146084.jpg


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Motor tube with centering rings glued in place and all conduit ready for epoxy.
ImageUploadedByRocketry Forum1402146317.139752.jpg


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The conduits carry a few lines: 2x CAT5e(one for ethernet and PoE, the other is pad interlocks, both are pad breakaway connection), staging igniter connector, several thermocouples running down the length of the motor tube, optical pyrometry fiber exposed to exhaust gas, three precision ground ejector pins for stage release, over pressure exhaust(part of stage separation pneumatics), pneumatic line for rail button retracts, and one last conduit that reenforces a piece of all thread that runs up to the aft AV bay bulk head.
ImageUploadedByRocketry Forum1402152073.327147.jpg



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Yes, the rail buttons(size 15) fully retract to conform to the body tube. They are pneumatically actuated and triggered from the flight computer. The button shown will get replaced by a conformal teflon button after final alignment to the body tube. During my initial research for this project I was absolutely amazed at how much drag rail buttons account for. I have seen numbers up around 30%. I understand the weight trade off may not be in my favor, but they sure look cool.
ImageUploadedByRocketry Forum1402155677.868875.jpg
ImageUploadedByRocketry Forum1402155775.690706.jpg



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Yes, the rail buttons(size 15) fully retract to conform to the body tube. They are pneumatically actuated and triggered from the flight computer. The button shown will get replaced by a conformal teflon button after final alignment to the body tube. During my initial research for this project I was absolutely amazed at how much drag rail buttons account for. I have seen numbers up around 30%. I understand the weight trade off may not be in my favor, but they sure look cool.

Ahh who cares about the weight that IS cool as hell :headbang:
 
Random Flying Object,

Sure would like to see the cam / rocker mechanism if you wouldn't mind sharing?

Feckless

The components are forever locked in fiberglass, but here is a picture of the install.

The inner carriage has slots that force cross pins in the button platform up and down. Addition slots in the surrounding chassis keep the pins from moving back and forth, therefore the platform can only translate up and down. The pneumatic is spring return to force the buttons out and in to a locked position. When pressure is applied to the piston it pushes the inner carriage, unlocking the button platform and pulling it down. When pressure is released the buttons pop back out and lock in to launch position.
ImageUploadedByRocketry Forum1402175682.034429.jpg



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The retrackable rail buttons are way cool looks like a lot of weight and headache. Could'nt you have the rail buttons spring loaded
 
Random Flying Object,

May I please ask what you're flying as data logger? Thermocouples and an optical pyrometer are “off standard” equipment.

Feckless
 
Last edited:
Random Flying Object,

May I please ask what you're flying as data logger? Thermocouples and an optical pyrometer are “off standard” equipment.

Feckless

This bird has two back up units and a primary flight computer. The aft backup unit is an Easy Mini, also in the aft AV bay is the motor management, back GPS, HD video w/OSD & 1.2GHz TX and the CO2 system for the retracts and staging separation. The forward AV bay has a backup TeleMega which runs a separate set of pyros. The primary flight computer is an NI sbRIO-9605. The primary computer controls: two sets of gyro/acc, GPS, HD video w/OSD & 4.5GHz TX a bio-direction 900MHz radio, payload interface, canard servos & locks, pneumatic chute deployment.

I had developed most of this in a previous rocket, so it shouldn't be too painful to get reinstalled in it's new home.

We will see how much of this stuff I actually get installed before Airfest??!

ImageUploadedByRocketry Forum1402193158.756755.jpg



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Random Flying Object,

Yeah, that's a well organized collection of parts. Is it fair to say your primary gig is automated test equipment?

Feckless
 
Last edited:
The conduits carry a few lines: 2x CAT5e(one for ethernet and PoE, the other is pad interlocks, both are pad breakaway connection), staging igniter connector, several thermocouples running down the length of the motor tube, optical pyrometry fiber exposed to exhaust gas, three precision ground ejector pins for stage release, over pressure exhaust(part of stage separation pneumatics), pneumatic line for rail button retracts, and one last conduit that reenforces a piece of all thread that runs up to the aft AV bay bulk head.
View attachment 174150

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Wow, I think I just rocket-geeked all over myself.
 
Random Flying Object,

Yeah, that's a well organized collection of parts. Is it fair to say your primary gig is automated test equipment?

Feckless

That is all the stuff my previous rocket barfed out after it decided to shear in half upon it's last touchdown.


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The retrackable rail buttons are way cool looks like a lot of weight and headache. Could'nt you have the rail buttons spring loaded

I didn't want anything thing else rubbing the rail, no trip rockers or the side of the rocket rubbing the rail. I wanted the buttons very rigid until commanded to retract, it was either pneumatic or direct electric solenoid, I chose pneumatic. As you can tell by the other pictures, I am not worried some much about the "headache" part.


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I have a feeling at this scale of project, the differential mass from more advanced control systems is actually pretty negligible, probably under 5%.
 
One last look before the aft section becomes entombed in fiberglass.

ImageUploadedByRocketry Forum1402267698.601151.jpg


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The conduits carry a few lines: 2x CAT5e(one for ethernet and PoE, the other is pad interlocks, both are pad breakaway connection), staging igniter connector, several thermocouples running down the length of the motor tube, optical pyrometry fiber exposed to exhaust gas, three precision ground ejector pins for stage release, over pressure exhaust(part of stage separation pneumatics), pneumatic line for rail button retracts, and one last conduit that reenforces a piece of all thread that runs up to the aft AV bay bulk head.
View attachment 174150



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:y:


Good lord, how many electronics do you have in the rocket? :p
 
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