Remove before flight tag

[Jonsayler]

Greetings. Anyone here used the "remove before flight" tag/pin switch option? I want to install one (simply because I find them cool) but you would have to remove this pin therefore arming your electronics (with BP loaded) before inserting the ebay into the upper and lower sections. Then replace the pin disarming the electronics before flight. And this would be done pre pad. So don't you need a switch anyway to disarm everything? I hope I explained that ok. Having the electronics on while BP is loaded before pad mount is a safety issue and a no no so I don't see any other way.

 

[Steve Shannon]

I use them.
Assemble your electronics bay.
Insert your switch rod.
Connect your charges to your terminal strips on top and bottom, or
Add your BP.

 

[OverTheTop]

I usually use a bamboo skewer inserted into the switches when working on the bench. After the electronics is assembled onto the rocket I can pull the bamboo skewer out of the hole, with needle-nosed pliers, and then insert the RBF pin. Takes about 20 seconds to do the swapover. Rocket is treated like a loaded gun when I'm doing that, and I wear a face shield. Nobody else nearby either.

 

[AndrewGil]

I have one of those for my 3" punisher and I just assemble the ebay then insert it into the coupler while the altimeters are beeping at me. Then put the pin back in and load my BP.

 

[cerving]

I use them to power off the airstart electronics on two-stagers before they're on the rail. LabRatRocketry.com makes some nice ones.

 

[OverTheTop]

I have one of those for my 3" punisher and I just assemble the ebay then insert it into the coupler while the altimeters are beeping at me. Then put the pin back in and load my BP.

That's the way I used to do it. I found the bamboo skewers stayed in better while I was handling the avionics on the bench. YMMV.

 

[David Schwantz]

Nope, Do not need to remove pin till upright on rail. Av bay stays assembled, prep av bay as normal, either run wires for E match out of bulkheads to BP charges. Now you can add charges on the outside of the bulkheads, with av bay removed. Pin is still in place coming out of switch band. Can assemble rocket completely without removing pin. Mount on rail, pull pin and fly.

 

[Voyager1]

I use them.
Assemble your electronics bay.
Insert your switch rod.
Connect your charges to your terminal strips on top and bottom, or
Add your BP.

Ditto!
I would expand on this to:

1. Assemble avbay as in above posts.
2. Insert RBF rod.
3. Connect ematches to fore and aft bulkplate terminals, or flying leads, if you use them.
4. At a safe spot away from main prep area, remove RBF rod to enable altimeter and test for continuity. Caution with wind gusts and/or bright light that might trigger an altimeter event.
5. If continuity is good insert, RBF rod and then add BP.
6. Instal avbay in rocket.

I have used this procedure for several years with redundant DD configurations very successfully.

 

[OverTheTop]

Some posts are forgetting that the OP has to insert the avionics into the rocket at some point, thus having to temporarily remove the pin and then re-insert it in the process. This is something I have to do for the nosecone (pin goes through airframe and nosecone shoulder) I usually use, so refer to my earlier posts.

It depends where the flyer breaks the rocket as to whether this is a problem or not, and also the design of the avionics bay (switch-band or not, etc).

 

[Handeman]

I use a screw switch in series with the pull pin that is accessable from the coupler that goes into the booster tube. I turn off the screw switch when loading the matches and powder. That way the pull pins don't get in the way while turning and prepping the rocket. Once everything is ready, I insert the pull pins with the Remove Before Flight flags and turn on the screw switches, put the rocket together and install any booster to av-bay shear pins and take it to the RSO. When on the pad, pull the pins to activate the electronics.
If the electronics don't activate, you forgot to turn on the screw switches. That's why locating them close to the switch band helps. You can reinstall the pull pins, pull the shear pins, lift the upper part of the rocket just a little, turn on the screw switches, put everything back together, and pull the pull pins again to continue your pad prep.

 

[David Schwantz]

Some posts are forgetting that the OP has to insert the avionics into the rocket at some point, thus having to temporarily remove the pin and then re-insert it in the process. This is something I have to do for the nosecone (pin goes through airframe and nosecone shoulder) I usually use, so refer to my earlier posts.

It depends where the flyer breaks the rocket as to whether this is a problem or not, and also the design of the avionics bay (switch-band or not, etc).

No you do not have to remove pin. Pin exits through switch band. Av bay can be installed completely assembled. I also use no switch band on some and the pin exits right at the break between booster and payload section. Again you do not need to remove pin until rocket on rail.

 

[Grog6]

I do electronics, so I know how stuff is prone to failure. I use two switches, one powers up the ebay, and the other 'ARM' pin hooks up the charges, and there are leds on the firing channels so I can be sure before I arm it. I also have a power monitor ic giving me a 'batt ok led, and a power on led. Led's waste power, but I consider it safety related; batteries are relatively cheap.

 

[OverTheTop]

No you do not have to remove pin. Pin exits through switch band. Av bay can be installed completely assembled. I also use no switch band on some and the pin exits right at the break between booster and payload section. Again you do not need to remove pin until rocket on rail.

Yes, if it is designed that way it works like that. Some people don't/can't design that way due to other constraints.

 

[David Schwantz]

True, I have a couple that have HED and I have to reach through the booster with allen to arm screw switch. But that is a different type of setup. What do you do for your switches?

 

[OverTheTop]

What do you do for your switches?

Me? Snap-action switches (aka microswitches). Refer to post #3 for processing steps.

 

[David Schwantz]

Ok, but why can't you do all that and have the entire av bay in your hand, and then install it into the airframe with out removing the pin?? I guess I am missing something.

 

[Steve Shannon]

Some posts are forgetting that the OP has to insert the avionics into the rocket at some point, thus having to temporarily remove the pin and then re-insert it in the process. This is something I have to do for the nosecone (pin goes through airframe and nosecone shoulder) I usually use, so refer to my earlier posts.

It depends where the flyer breaks the rocket as to whether this is a problem or not, and also the design of the avionics bay (switch-band or not, etc).

If a person makes a conscious design choice that sacrifices safety in exchange for some other benefit, they should re-evaluate their priorities..

 

[cerving]

Once you install the ematch WITHOUT POWDER to test continuity you should be able to install the disconnect pull-pin, and from that point on the AV bay is safed. Add the powder, put the rocket together with the AV bay, then pull out the pin when you're on the pad and vertical. Pretty simple, really.

 

[Jonsayler]

After reading the comments I realized I didn’t give enough information as well as a design flaw. The altimeters were placed as such that we didn’t install the pull pin switch within the framework of the vent band. It went into the frame of rocket then the top of the eBay section. This would require pulling pin before inserting eBay. First time with this and learning. We will redesign thank you for the comments.

 

[Steve Shannon]

After reading the comments I realized I didn’t give enough information as well as a design flaw. The altimeters were placed as such that we didn’t install the pull pin switch within the framework of the vent band. It went into the frame of rocket then the top of the eBay section. This would require pulling pin before inserting eBay. First time with this and learning. We will redesign thank you for the comments.

The “vent band” is more frequently called a “switch band.” In fact I don’t think I have heard it referred to as a vent band before, but it’s not wrong.

 

[Donnager]

The rockets I have with pull pins are set up with the pin through the vent band or through the edge of a body tube that doesn't affect disassembly. Once it is loaded, it is loaded, and you don't have to do anything but hook up recovery.

I normally work with mine with batteries disconnected while doing charge prep, and the batteries don't get connected until the e-bay is ready to go with the pin inserted, and then you can finish charge connections, depending. This works pretty well for LiPo's as I normally charge them before each launch, so not an extra step.

If you have your prep done, it is very quick to get one ready on the pad.

My only problem with screw switches is I've had them vibrate closed, or vibrate and lose the screw during handling/transport. Lightly fouling the threads helps this.