LOC 4" Black Brant X L1 Cert Build

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PeterP

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Hey all, this will be my first post on TRF! I decided I wanted to go for my HPR certifications after building rockets with my school’s rocketry program this past semester. So, I bought myself a LOC 4” Black Brant X to certify L1 and L2 with. I figured going with the biggest kit I could find would allow for easy sight during recovery, room for development, and the ability to fly K’s later down the line.

As a side note: I purchased my kit from Robert at Buyrocketmotors.com and had great customer service. Pricing was fair, same day shipping, and even though my kit was shipped without the motor tube (lol, still not sure why) Robert and LOC had the part shipped out the next morning.

I’m hoping this will be somewhat of a build thread and somewhat of an advisory for my certification process. Happy to be here!
 

DRAGON64

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Loc makes an awesome product for sure, I would expect you will fully enjoy building, flying and certifying on the Black Brandt X.

Welcome to forum!

Please keep us posted on your progress.
 

PeterP

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I started on a build plan today as I wait for some more parts to come in. So far I plan on using Bob Smith 30 min epoxy and a LOC N Ring 38mm mount adaptor (so I can have more options for a L1 motor. Most likely going to fly an Aerotech 38 DMS for L1 just so I don't have to spend money on a casing i'll use once).

The first question I have with this kit is:

The Black Brant X comes with a baffle system. This is intended to be a form of parachute protection, but would it beneficial or necessary to have a Nomex blanket on top of the baffle system? Worried about the ejection charge creating enough pressure to seperate but also not charring my chute.
 

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Theory

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first and fore most, welcome!

Second, BSI 30min will serve you well, no doubt, and as it is readily available (why I used it for my most recent build) you can get up and running in short order. If, however, you have time, and as you state that you are waiting for parts to come in, you may; I suggest looking at US Composites. Their wide range of epoxy systems will cover every aspect of hobby rockery and a better price than BSI systems.

As for your baffle, that is a personal preference kind of thing. Personally I see baffles as a 'soot and debris collection device' that will likely cause issues in the future. Others sware by them and devise very intricate custom built solutions. IMHO, you just cannot go wrong with a nomex, Kevlar, or other sort of blanket serving as a chute' protector.

Finally, I recommend purchasing a 38mm casing. RMS hardware is a very sound investment and one that you will be very happy with. I looked at the dates on come of my Aerotech RMS casings last night: 1996, 1998... and still ready to shove a rocket through the sky!
 

Nytrunner

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.......Most likely going to fly an Aerotech 38 DMS for L1 just so I don't have to spend money on a casing i'll use once).

......, but would it beneficial or necessary to have a Nomex blanket on top of the baffle system? Worried about the ejection charge creating enough pressure to seperate but also not charring my chute.
It's a good motor, but why would you only use a casing once? I have confusion!

Nomex is cheap insurance if you're worried. The ejection charge will pressurize the airframe regardless, but the baffle catches hot particles and allows the gas to cool a bit before reaching your parachute. It's a good system.
 

PeterP

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It's a good motor, but why would you only use a casing once? I have confusion!
I have the full intention to fly 54mm J,K motors with this kit and moving forward. However, there are limited 54mm options for my L1 cert. With a kit this big, I wouldn't want to fly anything less than an I. I know that CTI and AT have 54mm I motors, but they are 1 grain. Thats where the 38 DMS idea came in. Just popping in an I500T for my L1 and then purchasing 54mm casings/reloads after that. Dropping $100 on a 38 5-6 grain case isn't something that is in my immediate future or budget. Am I crazy?
 

Nytrunner

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Nope, not crazy. You know your budget best.

But I'd be remiss if I didn't point out that a 5 grain pro38 with 2 spacers unlocks an amazing range of L1 flying ;) where a ton of good flying experience can be had before hopping up into wallet killing territory (L2)

Your journey is your own though, keep flying and have fun!
 

PeterP

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But I'd be remiss if I didn't point out that a 5 grain pro38 with 2 spacers unlocks an amazing range of L1 flying ;) where a ton of good flying experience can be had before hopping up into wallet killing territory (L2)
Very true, didn't even think about that! I'll keep that in mind when the time comes. If everything goes to plan, I should be ready to go at the March 9 HARA launch.
 

Nytrunner

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Ah! We look forward to having you down!
(and by we, I mean whoever else from the club is there. I may be out of town that weekend)
 

Theory

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Also, the AT 38/720 case supports the I600 (awesome motor) as well as some solid J loads to including the J500G

No doubt I know all about a budget, just don’t want you to regret purchasing an expensive single use motor
 

PeterP

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I did have the realization that L2 motors would get expensive if flown often, thanks to you guys. I guess my mantra would be that I would rather fly often and learn, than fly powerful and rarely. So the rush for 54mm isn't as important. Glad I ordered that motor adapter!

The reason budget is such a big role in this build is because I am a college student. Our only certified member (L3) of the rocketry club is graduating this semester, and I figured I could be one of the people who stepped up and fill that place. I also plan on interning this summer, so having that on my resume is a plus. I set aside $300 total out the door for my certification and I have about $85 left of that for that motors/hardware. Which leads me to this:

No doubt I know all about a budget, just don’t want you to regret purchasing an expensive single use motor
What makes DMS motors "expensive" compared to reloads? It seems that reloads are usually only $5-10 cheaper than SU so that means you have to fly 10+ to break-even on the hardware. I understand the appeal due to more variety in motor selection, but other than that? Are reloads geared towards the monthly flyers?
 

Theory

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I must say that I stand corrected.

An I600 reload is $67.99 and an I500 DMS is 69.99. Cant argue tgat $2. No doubt the DMS is the way for you to go with your goal and budget
 

solid_fuel

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Does the DMS ship with Hazmat? That’s where many single use motors get expensive. One can have 38mm Loki H, I and perhaps even a J motor shipped with no hazmat. Of course if you buy from an on field vendor this is all moot. Regarding the baffle I use them in some builds and don’t use them in others. I like them mostly for the way the harness can mount right to it and how it keeps the laundry from sliding down the tube during boost. I tend to still use some form of chute protection even when using a baffle. One drawback of the baffle is they limit the length of motor; once installed you won’t be able to use a longer motor so plan ahead to make sure the longest motor you want to fly will fit with baffle installed.
 

PeterP

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Does the DMS ship with Hazmat? That’s where many single use motors get expensive. One can have 38mm Loki H, I and perhaps even a J motor shipped with no hazmat. Of course if you’re buy from an on field vendor this is all moot. Regarding the baffle I use them in some builds and don’t use them in others. I like them mostly for the way the harness can mount right to it and how it keeps the laundry from sliding down the tube during boost. I tend to still use some form of chute protection even when using a baffle.
Yes, the DMS does ship with Hazmat. Chris Short will be at the HARA launch so I was just planning on stocking up from him. Otherwise, the Hazmat can be a deal breaker. In any case, reloads also have the Hazmat applied so what exactly is the appeal?

Also, I did end up ordering a 12x12 blanket on top of the baffle system. Figured not to risk recovery systems on cert flights. ;)
 

Theory

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The appeal is options, and, even though minimal in some cases, a reduced cost.
 

solid_fuel

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The appeal is also no Hazmat shipping on Loki H and I motors. All reloads for the 38/480 case ship with no hazmat. And are $20 cheaper per load than the AT I600 shown as an example above. Full motor: case, nozzle, washer, and forward bulkhead cost $110. Compared to flying the AT single use the break even point is at 5.5 flights. Even with Loki motors being simple and fast to assemble DMS or single use certainly is significantly more convient as you don’t have any down time assembling the motor or cleaning the case after the flight. Also it is heartbreaking when you don’t recover a reload case even if it has already covered it’s break even point. Just wanted to put this out there so you know what the options are.

8287479A-42E3-4882-BD5C-345FF0AF799A.png


https://www.csrocketry.com/rocket-motors/loki-research/38mm/480.html
 
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Theory

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Truth on the Loki motors, though the AT I600 has a over 100 Ns on the non-Haz-Mat Loki
 

solid_fuel

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At least that justifies the extra $20. :)

And damn! it’s well over 100 more Ns
 

Theory

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Yes, the I600 is a beast of a motor!!! A true 99% I.
 

PeterP

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Finally got all my parts today! I plan on starting the build this weekend, which will give me exactly one week until its maiden launch with HARA (pending weather). Doing a L1 build in a week will add to the fun! Looking forward to it.

Also, I've narrowed down my motor choices between an I280DM and an I500T. Both sim to about 2700 feet with mach .5 and about 9-15 G's. Any red flags? I'd rather fly the dark matter, but it depends if the field allows. I will keep you all posted.
 

Theory

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No red flags other than your very short time line. Properly built, you rocket can take 4 times the G load with out breaking a sweat.

As for the time line, be careful. Better to do it “right” than do it “right now”
 

PeterP

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Thankfully next week is spring break for me, so I will have more time than usual for building. However, I agree about building it right. If I’m not ready or don’t feel comfortable I will wait till next launch
 

Nytrunner

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We've got 8' 1010 rails (maybe a 10' as well, I forget) and 8' 1515s (we do have a 12' 1515 for any big'uns that show up)

Look at your simulations and make sure you account for rail button distance, and that you'll have a safe rail exit speed on the lower thrust motor. (pay attention to the thrust curve at the 1st 1/4 second, is it still over 5:1?). Once that top button clears the rail, it is free to yaw. (see hasty "effective rail length" sketch below)

On the subject of Dark Matter......I and a few others in the club are in favor of spark motor use on occasion, others (and a couple in leadership) are wary and don't want rails chewed up by the sparking particles. I've been lobbying for a designated "beater rail" for sparkies. Let me know how it goes!



upload_2019-2-25_12-55-1.png
 

Theory

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Thankfully next week is spring break for me, so I will have more time than usual for building. However, I agree about building it right. If I’m not ready or don’t feel comfortable I will wait till next launch
good deal, and spring break should give you some time. happy to hear that you will be working on a rocket and not working on a 30 pack of cheap beer!

I only caution you to go slow as that was the downfall of my first cert 2.

STORY TIME:
back at the 1998 battle park launch, 5 months after my 18th birthday I planned for both my L1 and L2. L1, no problem, L2 test, no problem (studied for that more than any test that year). prepped my custom built 5.5" diameter rocket "Theory III." all went together well, however, in the excitement I made a catastrophic error while assembling my J350 that lead to a failure of the forward closure and the ejection charge firing about 1 second into the flight. I had failed to grease the liner around the delay element (which in hind sight I thought was a touch lose). the mishap destroyed the rocket, burned the entire recovery system and ended my launch for the day. I wouldn't get my L2 until 14 months later.

take a breath, don't rush fit any parts or skip any steps, wait for everything to cure properly and all will be good.
 

Bat-mite

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Have fun with your build. I second the notion to get a Loki casing (or two, or three). Lots of H and I reloads ship with no HAZMAT.

If you can make it to MDRA on March 9, One Bad Hawk and Performance Hobbies will be there with Loki motors for sale.
 

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GalantVR41062

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The AT I280DM and I500T are not the same motor, and will result in different flight profiles.

I think the I500t will go higher then the I280dm, the question is how much and getting the delay right for deploying right at apogee.

I like to tweek thrust curve numbers once I have test flights on my rockets to better select motors and delay times.

~John
 

PeterP

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I appreciate all the recent info and advice! As far as the difference between the two motors: yes, they will provide very different flights. The I500 will give a velocity off 8' rod of about 60 mph and go 300 feet higher than the I280. The I280 will leave the rod at 40mph and give a much slower/easier to track flight. Also, sim is saying a 10 second delay would put me right around optimal deployment (7 mph), so I am hoping someone at the field will be kind enough to let me borrow a DAT tool to take off 4 seconds. I280 is probably the safer option out of my motor choices as long as the lift off velocity is enough and the club allows sparky motors. If not, the I500 will do just fine and scream off the pad. Just hoping it won't be too fast. Low and slow for cert flights never hurts.

As far as the Loki casings/Hazmat information: I will definitely look at purchasing that stuff after my cert flights and have a little bit more cash to spend. Thanks for referring those.

I've been messing around with OpenRocket and made a model of the paint scheme I think I'm going to go with. Still on track for building and budget this weekend! I'm tired of staring at unassembled pieces, haha. Just hoping the weather holds out...
 

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Nytrunner

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Assume 1/32" of delay per second removal.
4 seconds means ~1/8" deep divot

Take a 1/4" drill bit, mark location with tape, twist. That's how I did my L1 delay before I got one of the tools.
 

Theory

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Assume 1/32" of delay per second removal.
4 seconds means ~1/8" deep divot

Take a 1/4" drill bit, mark location with tape, twist. That's how I did my L1 delay before I got one of the tools.
good tip! though I would state that a DAT tool, or any delay adjustment tool that fits the motors you are flying, is a piece that needs to find its way into the budget and subsequently into your range box. call it part of the price of admission.
 

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