Terrier-sand hawk build thread

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They heard all the news about Starship and New Glenn and decided to check it out. They haven't read the NAR bylaws though, no live payloads allowed.

Ants are Fine.

Dr. Zooch, Wes, used to launch them all the time. I have a 'Mock-u-mentary' video of his launching a Dr. Zooch Gemini with 2 ants in the capsule. He had one of my Cameras filming them during the flight.

You can see their Antennas move. It was done like the 60s Air Force films, it's a hoot.
I need to get his permission to post it to you tube. I have not seen Wes since we were at the CAPE in 2019 at NARCON

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I just realized I have no idea how to do vent holes since the ebay is a hach! @cerving do you know how to do it? has anyone done a hach EBay before?

ps in the videos he just doesn't do them but that seems like a bad idea.
 
I just realized I have no idea how to do vent holes since the ebay is a hach! @cerving do you know how to do it? has anyone done a hach EBay before?

ps in the videos he just doesn't do them but that seems like a bad idea.
I used one 5/32in hole in my hatch ebay shown here. Mostly this was for screw switch access - this cover is so leaky I'd bet it'd be fine without anything.

And don't forget, this forum (and other sites) are great resources - many projects have documented how to do this type of stuff. I've learned a bunch just reading build threads here...: http://lmgtfy2.com/?q=site:rocketryforum.com+hatch+ebay
 
I agree that the hatch is likely leaky enough for a good read on apogee and descent. With venting on just one side of the rocket, it will be prone to 'noise' from swirling/changing gusts on the launch rail - but you're using a Proton, so as long as you're using the accelerometer launch detect, you'll be fine. And I highly recommend using the accelerometer launch detect and timing stage ignition from booster burn out options.

I also recommend you seriously consider the first flight in 'boosted dart' mode. A full up flight in every respect, with upper stage motor in place and all dual deploy active, but the sustainer igniter NOT in the motor. Maybe in a small separation charge, though. Partly, it shows you that everything works. But you can also look at the recorded baro altitude data and see how it looks during powered flight. My two stagers always showed some weird baro behavior during boost, and you need to take that into account if you are using the accel alt / baro alt difference condition for extra staging safety. I will admit that I was pushing my two stagers to the -shortest- coast time I could. My goal wasn't altitude, it was a cool looking from the ground flight.
 
How long is your motor mount tube? I kind of DIY'd an ebay for just the LOC kit but didn't realize how short it would make the motor mount. It might not matter, but curious how much length you have to work with. I was looking at 38mm DMS long burn motors like the I40 for this rocket.

My 3d printed sled ended up blowing out under ejection charge pressure (it was quite thin) on first flight, ended up sealing up the hatch and moving everything to central payload section
 
How long is your motor mount tube? I kind of DIY'd an ebay for just the LOC kit but didn't realize how short it would make the motor mount. It might not matter, but curious how much length you have to work with. I was looking at 38mm DMS long burn motors like the I40 for this rocket.

My 3d printed sled ended up blowing out under ejection charge pressure (it was quite thin) on first flight, ended up sealing up the hatch and moving everything to central payload section
it is same length the kit comes with, 11 inches I think but you'd have to check. an I40 would be fun if I ever fly outside the east coast.
 
In the wrap up of the build series, Tim mentions cutting the sled hatch shorter to prevent ejection charge soot from getting up and over the bulkhead and into the ebay (link, around time 4:32) I think thats a good idea. You might want to think about glueing shut that section above the bulkhead, it feels like its also risking blowing out the hatch and having a parachute fail to deploy. That happened to me with a 3d printed sled of the same design. The plywood is definitely strong enough, but the body tube hatch that is just notched in there might not be. The only change is needing long leads on your ejection charge since you need to be able to pass the leads in from all the way at the front of the body tube section.Screenshot 2025-01-29 at 9.44.22 AM.png
 
I've been reviewing how I do staging in prep for going higher power, and I want to mention something you might want to consider with your personal risk tolerance. And emphasis on _personal_, I think these choices are pretty personal depending on risk tolerance.

I see you are planning to fly a single proton board. You might want to consider flying an eggtimer quantum + apogee or other small DD altimeter, instead of a single board. The reason is this: what feels like a "redundant" deployment setup (motor eject + electronic apogee deployment) is actually not, if the proton fails (e.g. bad battery connection), it won't light the sustainer _and_ it won't deploy the parachutes, so it'll come in ballistic. I had that happen to me recently with the TTV + Simple Timer kit, and that was really small and light, but the idea of something bigger coming in ballistic is too much for my risk tolerance.

If you fly two altimeters, one for sep+ignition, the other for parachutes, at least you'll have a properly redundant setup (and size might work in the sled, or you can put the apogee in the nosecone.

If you feel ok keeping the single point of failure, I'd recommend flying the sustainer alone first. That way if it gets off the pad, it'll have redundant deployment mechanism and you'll get to test the electronics.
 
I've been reviewing how I do staging in prep for going higher power, and I want to mention something you might want to consider with your personal risk tolerance. And emphasis on _personal_, I think these choices are pretty personal depending on risk tolerance.

I see you are planning to fly a single proton board. You might want to consider flying an eggtimer quantum + apogee or other small DD altimeter, instead of a single board. The reason is this: what feels like a "redundant" deployment setup (motor eject + electronic apogee deployment) is actually not, if the proton fails (e.g. bad battery connection), it won't light the sustainer _and_ it won't deploy the parachutes, so it'll come in ballistic. I had that happen to me recently with the TTV + Simple Timer kit, and that was really small and light, but the idea of something bigger coming in ballistic is too much for my risk tolerance.

If you fly two altimeters, one for sep+ignition, the other for parachutes, at least you'll have a properly redundant setup (and size might work in the sled, or you can put the apogee in the nosecone.

If you feel ok keeping the single point of failure, I'd recommend flying the sustainer alone first. That way if it gets off the pad, it'll have redundant deployment mechanism and you'll get to test the electronics.
I did consider that and I don't have a room for a quantum with a battery. I can fit a quantum with the same battery but there's no room for wiring in that case. an apogee in the nose is probably the best idea if I went that way, I'll have to think on that.
 
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In the wrap up of the build series, Tim mentions cutting the sled hatch shorter to prevent ejection charge soot from getting up and over the bulkhead and into the ebay (link, around time 4:32) I think thats a good idea. You might want to think about glueing shut that section above the bulkhead, it feels like its also risking blowing out the hatch and having a parachute fail to deploy. That happened to me with a 3d printed sled of the same design. The plywood is definitely strong enough, but the body tube hatch that is just notched in there might not be. The only change is needing long leads on your ejection charge since you need to be able to pass the leads in from all the way at the front of the body tube section.View attachment 691728
how am I going the thread it thru the hole into the bay? I can't spend all day trying to line things up just so and hope it goes thru.
 
how am I going the thread it thru the hole into the bay? I can't spend all day trying to line things up just so and hope it goes thru.
Yeah its not ideal. Two ways I've done:
1. keep a length of wire long enough to come out of the body tube (like old igniter wire) and glue that in to run through the bulkhead, then attach your charge to that wire when the time comes.
2. Use a stick and with a bit of tape and the igniter and fish it down into the opening. wasn't as bad as I expected.

But I'm very new to this, there might be simpler ways
 
I did consider that and I don't have a room for a quantum with a battery. I can fit a quantum with the same battery but there's no room for wiring in that case. an apogee in the nose is probably the best idea if I went that way, I'll have to think on that.
I think I'll go for no apogee at least for now (it'd cost 60 dollars with all the needed accessories) I'll consider it as a future upgrade.
 

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