Hi I'm doing a L1 Cert attempt this November and need to know what the "speed limit" for a parachute on a Loc-IV?

[Clay Lowery]

Hi I'm doing a L1 Cert attempt this November and need to know what the "speed limit" for a parachute on a Loc-IV?

 

[dvdsnyd]

Not sure what you mean? Deployment speed? Should be as low as possible. Are you running simulations?

 

[Clay Lowery]

Not sure what you mean? Deployment speed? Should be as low as possible. Are you running simulations?

Yes, I just wanted to make sure.
Thank you

 

[tsmith1315]

Hey Clay, I assume you're using motor ejection and looking for the best delay time?

For single deployment, ejection within a couple seconds of apogee is what I aim for. I'm not too particular about a speed.

Are you flying at GRITS?

 

[Clay Lowery]

Hey Clay, I assume you're using motor ejection and looking for the best delay time?

For single deployment, ejection within a couple seconds of apogee is what I aim for. I'm not too particular about a speed.

Are you flying at GRITS?

Yes, I am, that's where I'm doing my l1 cert.

 

[JRL303]

Yikes...

 

[Clay Lowery]

Yikes...

?

 

[tim cubbedge]

Keep it under 25 fps. 15-20 fps is better but grits has a pretty soft field. Good luck!

 

[tsmith1315]

?

My non-specific recommendation, I assume.

Keep in mind a motor delay has 20% tolerance, up to 3 seconds max. So I see the ejection delay as more of a range than a specific time.
There's no need in analyzing to decimal places. Unless you like that, of course.

I'll be there rootin' for you!

 

[Five]

The body tube that comes with the loc lv is a good tube

 

[Hobie1dog]

isn't it more about having it eject at apogee

 

[Steve Shannon]

isn't it more about having it eject at apogee

Eject at apogee, but be sure and launch it vertical so it doesn’t develop horizontal velocity. A lot of people, when they’re starting out, try to avoid drifting by tilting the launch pad into the wind. That’s usually a bad thing because the rocket will arc over even more when flown into the wind. I’ve seen lots of zippers from people trying to avoid a walk. Apogee is the slowest vertical velocity, but has no effect on horizontal velocity. Just launch it vertically and don’t try to outthink the wind.

 

[Hobie1dog]

Eject at apogee, but be sure and launch it vertical so it doesn’t develop horizontal velocity. A lot of people, when they’re starting out, try to avoid drifting by tilting the launch pad into the wind. That’s usually a bad thing because the rocket will arc over even more when flown into the wind. I’ve seen lots of zippers from people trying to avoid a walk. Apogee is the slowest vertical velocity, but has no effect on horizontal velocity. Just launch it vertically and don’t try to outthink the wind.

I've made that mistake before.

 

[Tech 68]

I'll "accordion tape" my shock cord (at least partially) to bleed off energy and put some sort of cushion on the shock cord so when it's fully extended, the cushion is contacting the edge of the body tube. It's not a perfect solution, but it helps.

 

[Zeta]

timing is everything

 

[waltr]

I'll "accordion tape" my shock cord (at least partially) to bleed off energy and put some sort of cushion on the shock cord so when it's fully extended, the cushion is contacting the edge of the body tube. It's not a perfect solution, but it helps.

Yes, that does help reduce the Shock when the cord fully extends.
The other method is to braid the cord. I do this on my LOC Goblin and had a delay go very long but not damage when the chute opened.

 

[techrat]

FYI, has anybody tried this to prevent zippering?? What if you were to wrap some shock cord around a disposable item, like a used black powder "E" motor? As the shock cord will spend some time unravelling (even a fraction of a second may be enough time), it may be enough to keep the cord from ripping apart the body tube.

 

[Steve Shannon]

I've made that mistake before.

Almost everyone does.

 

[MidOH]

I soak the end of my paper tubes with CA. Then I Z fold some of the cord in some inside out masking tape. Like a riggers harness shock absorber:

On low to medium power rockets, Z fold only the amount of cord that you don't exactly need. Too tight with the tape, and it might not unfold completely.

Put 2" of aluminum tape on the shock cord to protect the cord where it contacts the edge of the tube. One piece of masking tape over that so visual wear is easier to spot.

 

[techrat]

Like a riggers harness shock absorber:

Ohh, where did you get that image? I actually need one of those for the next time I'm climbing a radio tower...

 

[Rob Campbell]

Yes, I am, that's where I'm doing my l1 cert.

GRITS is a great event. I went last year and had a great time. I plan on being there again this year.

 

[MidOH]

Ohh, where did you get that image? I actually need one of those for the next time I'm climbing a radio tower...

https://guardianfall.com/
Can you guys use a shock damper? Mine extends 8' as it drops me. Often useless because I'm only 15' off the ground.

 

[Hobie1dog]

Ohh, where did you get that image? I actually need one of those for the next time I'm climbing a radio tower...

Whatever they are paying you to climb up a radio tower, it's not enough.

 

[techrat]

Whatever they are paying you to climb up a radio tower, it's not enough.

Definitely, since it's zero. I'm a member of a radio club, and I'm one of the few people under 80 so it's up to me to maintain the antennas at the club. It's not that bad, but your feet hurt after an hour of so of standing on those rungs.