The Path to Level 1: Acquisition, Build, Test, and Certification Attempt Thread

[smstachwick]

After taking a good, long, hard look at my rocketry goals, I've decided to move up my timetable and attempt to acquire a Level 1 certification in 2023. To that end, I have selected an airframe and various motors that I believe will be suitable for test and certification flights, based on information gleaned from online resources which include TRF. I intend to purchase the airframe kit on New Years' Day, which is just a few hours away as I post this. I'm practically jumping up and down with excitement, I finally get to pull the trigger on a lifetime goal!

My selection is the Enerjet by Aerotech Astrobee D, which I will assemble fully by the book at a leisurely pace, and attempt to get a really good-looking finish. I will then proceed with a rigorous flight test program on Enerjet by Aerotech F67-6W and G74-6W motors, which are recommended by Aerotech's 2021-2022 catalog. I also validated these motor selections in OpenRocket and ThrustCurve, with simulations set for both calm and severe winds (20mph). In both cases, the F67-6W is less than a second long, and the G74-6W is less than a second short. Both are predicted to stay under DART's 1000 ft ceiling. Rail departure speed, stability margin, thrust-to-weight ratio, and liftoff mass are all legal and good.

Should these flights go well and I'm left confident that I could recover the rocket on H power at a high-power site, I will get my paperwork in order, arrange for certification witnessing, and make a certification attempt on an AeroTech H115DM. Apogee's product page recommends a delay drilled to 9 seconds, which is corroborated by my findings in OpenRocket and ThrustCurve. Because the Universal Delay Drilling Tool drills in 2-second increments down from the 14 that the motor comes with, I'll probably be going for 10, as the simulations indicate that in calm winds, the optimum delay will be very slightly more than 9 seconds. Things were very dicey with severe winds, with the optimal delay time drifting wildly through the 8- to 9-second range as I ran the OpenRocket simulation multiple times, so the flight will have to be made in cooperative winds, I'd say no more than 5mph. I will plug in more precise data for my selected launch site's coordinates, elevation, and predicted atmospheric conditions when the time comes for a certification attempt.

This thread will document my progress through this plan, as well as all of the setbacks, delays, and rethinks that I may will experience along the way. I'll get pictures where I can, and I will also try to get my hands on a suitable camera system to mount on the rocket, and capture the flights on video.

 

[Hobie1dog]

looking forward to it.

 

[NateB]

Good luck!

During the launch when I certified my L1, there were a lot of students certifying as well. Winds were stronger than I wanted and many of their rockets were flying away. I was able get an appropriate motor on site to keep it low and close, but I almost held off for another day. I wouldn't be afraid to run several sims for weather and be willing to delay the flight if you need to.

 

[smstachwick]

Good luck!

During the launch when I certified my L1, there were a lot of students certifying as well. Winds were stronger than I wanted and many of their rockets were flying away. I was able get an appropriate motor on site to keep it low and close, but I almost held off for another day. I wouldn't be afraid to run several sims for weather and be willing to delay the flight if you need to.

I might consider that if I get better data for turbulence and standard variation, and if it holds constant long enough for me to prep the rocket the way I need to. In the absence of any real idea of what winds aloft look like at Holtville or Lucerne Valley, I put in the 10% default. I suspect that the randomness in which OR applied that is what gave me the wild variations in delay time. Some instances of the simulation tumbled under thrust and had negative optimal delay times, others had reasonable delay times but gave me 70mph deployment speeds. Ick!

 

[FlyBy01]

After taking a good, long, hard look at my rocketry goals, I've decided to move up my timetable and attempt to acquire a Level 1 certification in 2023. To that end, I have selected an airframe and various motors that I believe will be suitable for test and certification flights, based on information gleaned from online resources which include TRF. I intend to purchase the airframe kit on New Years' Day, which is just a few hours away as I post this. I'm practically jumping up and down with excitement, I finally get to pull the trigger on a lifetime goal!

My selection is the Enerjet by Aerotech Astrobee D, which I will assemble fully by the book at a leisurely pace, and attempt to get a really good-looking finish. I will then proceed with a rigorous flight test program on Enerjet by Aerotech F67-6W and G74-6W motors, which are recommended by Aerotech's 2021-2022 catalog. I also validated these motor selections in OpenRocket and ThrustCurve, with simulations set for both calm and severe winds (20mph). In both cases, the F67-6W is less than a second long, and the G74-6W is less than a second short. Both are predicted to stay under DART's 1000 ft ceiling. Rail departure speed, stability margin, thrust-to-weight ratio, and liftoff mass are all legal and good.

Should these flights go well and I'm left confident that I could recover the rocket on H power at a high-power site, I will get my paperwork in order, arrange for certification witnessing, and make a certification attempt on an AeroTech H115DM. Apogee's product page recommends a delay drilled to 9 seconds, which is corroborated by my findings in OpenRocket and ThrustCurve. Because the Universal Delay Drilling Tool drills in 2-second increments down from the 14 that the motor comes with, I'll probably be going for 10, as the simulations indicate that in calm winds, the optimum delay will be very slightly more than 9 seconds. Things were very dicey with severe winds, with the optimal delay time drifting wildly through the 8- to 9-second range as I ran the OpenRocket simulation multiple times, so the flight will have to be made in cooperative winds, I'd say no more than 5mph. I will plug in more precise data for my selected launch site's coordinates, elevation, and predicted atmospheric conditions when the time comes for a certification attempt.

This thread will document my progress through this plan, as well as all of the setbacks, delays, and rethinks that I may will experience along the way. I'll get pictures where I can, and I will also try to get my hands on a suitable camera system to mount on the rocket, and capture the flights on video.

I would recommend a Jolly Logic chute release.

 

[JRL303]

I might consider that if I get better data for turbulence and standard variation, and if it holds constant long enough for me to prep the rocket the way I need to. In the absence of any real idea of what winds aloft look like at Holtville or Lucerne Valley, I put in the 10% default. I suspect that the randomness in which OR applied that is what gave me the wild variations in delay time. Some instances of the simulation tumbled under thrust and had negative optimal delay times, others had reasonable delay times but gave me 70mph deployment speeds. Ick!

Come again?

 

[FlyBy01]

You’re really over thinking this, no matter how accurate you drill the delay, there will be an error in the delay just because of variables in production that are beyond your control.

 

[John_461]

Sounds like you have a solid plan. Stick to it and you'll do great!

Don't stress too much about the delay time. It's kind of like horseshoes and hand grenades...close enough is good enough.

 

[smstachwick]

You’re really over thinking this, no matter how accurate you drill the delay, there will be an error in the delay just because of variables in production that are beyond your control.

Good point. I tend to underbuild and underpack my rockets, as I tend to underestimate motor performance. I hadn’t taken into account that this will be a much more sturdy build and that conditions will probably be fine, not to mention the delay tolerances.

 

[smstachwick]

I placed the order at HobbyLinc shortly after midnight last night. It should depart Atlanta on 1/6 and arrive sometime between 1/17 and 1/19. I may try to pick up some build supplies in the meantime, possibly some medium-viscosity cyanoacrylate glue, as specified in the instructions I found online.

https://www.manualslib.com/manual/1365016/Aerotech-Astrobee-D.html
Currently I’m looking at building it in Flight Mode, for simplicity.

 

[mikec]

A few words of advice, not that I want to encourage overthinking, as IMHO there's an excellent chance you can build this rocket stock and do your L1 without problems.

1) built stock, it comes down in two pieces, so twice the chance to lose something. You'll be going to 1500+ feet, so you probably won't lose anything unless it's quite windy, but be warned. (On the plus side you are immune from snap-back fin damage which has caused many an L1 attempt to fail.)

2) many people will advise you to not use the baffle mesh system. I think it's fine but it's something to consider.

3) Be careful flying this at Fiesta, even on an F, unless it's very calm or you want to go swimming.

4) The standard Aerotech fins are probably robust enough even without adhesive to hold up, but in my experience they tend to be tight, so dry-fit before you apply CA and even before you install the MMT in the rocket.

5) I'd probably put rail buttons on it even though it doesn't come with them.

 

[Neutronium95]

I'm not a big fan of baffles, or of elastic shock cords. I'm not sure about this kit in particular, but you might want to fly longer motors at Holtville or Lucerne in the future, and some baffles can restrict the available motor length. Just use a good long length of Kevlar and a decent size nomex blanket.

Cardboard rockets can take a lot more motor than some people think. I think that the tubes that Aerotech uses are thicker wall than what BMS uses for their 3" School Rocket, and I fly mine on H399s all the time.

 

[smstachwick]

A few words of advice, not that I want to encourage overthinking, as IMHO there's an excellent chance you can build this rocket stock and do your L1 without problems.

1) built stock, it comes down in two pieces, so twice the chance to lose something. You'll be going to 1500+ feet, so you probably won't lose anything unless it's quite windy, but be warned. (On the plus side you are immune from snap-back fin damage which has caused many an L1 attempt to fail.)

2) many people will advise you to not use the baffle mesh system. I think it's fine but it's something to consider.

3) Be careful flying this at Fiesta, even on an F, unless it's very calm or you want to go swimming.

4) The standard Aerotech fins are probably robust enough even without adhesive to hold up, but in my experience they tend to be tight, so dry-fit before you apply CA and even before you install the MMT in the rocket.

5) I'd probably put rail buttons on it even though it doesn't come with them.

Thanks for the input. I saw a video that a fellow posted on YouTube doing precisely the motor/airframe combo I’m looking at, and he tied them together. Currently I’m looking at building it to separate, mostly because I know this field well and I routinely get “fire and forget” rockets back there. My secret is that I’m generally more cautious than I was when I was doing this as a kid.

Apogee says the kit comes with conformal rail guides now, I’m assuming 1010. I don’t think the buttons will be needed.

I do tend to play around with the kit components a bit before I sit down to build, if only to get pictures, so a dry fit test is definitely on the table. Again, leisurely pace.

I may extend the motor mount tube to accommodate a very long casing, I’d only need 5 more centimeters or so to fit a CTI 6G-XL casing. But that won’t be during the initial build, I think.

 

[jmasterj]

You'll need more than that if you're going to use the aerotech baffle (which I personally like a lot). The steel wool takes up at least 4 inches. If you do extend the MMT, make sure you get a tube with the same OD exactly, otherwise the tight friction fit of the AT kit components won't work right.

Oh, and like @mikec said, definitely dry fit the fins. You may have to to bend them back and forth a little to get them to stay vertical, as well. I've skipped that and have a couple AT kits where the fins aren't perpendicular to the tube surface. Doesn't make them worse at their job, but it doesn't look great.

 

[smstachwick]

Obviously five power ranges is a bit silly, so I'll definitely be sticking to the three I outlined in my plan, but it's fun to think about nonetheless. Maybe somebody else will take up the E28 challenge...

 

[OverTheTop]

Enjoy the journey to L1. Sounds like a good approach. Most of all HAVE FUN .

 

[DRAGON64]

I have built and flown the Astrobee D from Aerotech, very fun build, and a very nice looking rocket. Built stock, and recovered as designed, the upper half got bent in the middle on landing, as the chutes seemed a little small. The upside, I did get Homer Hickam's signature on the rocket.







Blurry image from an older disc camera from the late 1990's...

 

[boatgeek]

I may extend the motor mount tube to accommodate a very long casing, I’d only need 5 more centimeters or so to fit a CTI 6G-XL casing. But that won’t be during the initial build, I think.

The front of the motor can extend well forward of the motor mount, so you would just need to move the baffle up. For a long casing like the CTI 6GXL, the motor mount probably doesn't need to be longer than half of the casing length.

Sounds like a fun project!

 

[jmasterj]

The front of the motor can extend well forward of the motor mount, so you would just need to move the baffle up. For a long casing like the CTI 6GXL, the motor mount probably doesn't need to be longer than half of the casing length.

Sounds like a fun project!

The Aerotech baffle is inside the motor mount tube.

 

[dpower]

The Astrobee-D is my favorite Aerotech kit. I made only minor mods to the build. 1) Bought an extra coupler, cut the tubes, so the bottom section was longer, providing more recovery room, and put a bulkheadin the top section. 2) Tied the 2 sections together with a LONG nylon shock cord, and a larger chute, so I didn't have to chase 2 pieces. 3) Found some springs at the HW store the same size as the aluminum tube antennas, perfect press fit, and much more tolerant of landings or getting snagged by the shock cord. Never had one break off. Otherwise it was built stock, using medium CA, which makes a really strong build. I flew it on G77R, H165R and H210R motors, it flew great!

What would I do different? As much as I like the AT baffles (yeah I know a lot of folks don't), you need to be careful when flying RMS-Plus motors. The large red cap will block the baffle on ejection, likely resulting in a lawn dart. I forgot to do that on its last fligh! So if you use the baffle, don't use the red cap, just use masking tape to seal in the ejection BP. Alternatively, build without the baffle, so the red cap can eject up & out. If you use CTI motors, this won't be a problem.

All AT kits now come with rail guides and an aluminum retainer, which are both really nice. This will make a great L1 rocket, enjoy the journey!

 

[smstachwick]

The Astrobee-D is my favorite Aerotech kit. I made only minor mods to the build. 1) Bought an extra coupler, cut the tubes, so the bottom section was longer, providing more recovery room, and put a bulkheadin the top section. 2) Tied the 2 sections together with a LONG nylon shock cord, and a larger chute, so I didn't have to chase 2 pieces. 3) Found some springs at the HW store the same size as the aluminum tube antennas, perfect press fit, and much more tolerant of landings or getting snagged by the shock cord. Never had one break off. Otherwise it was built stock, using medium CA, which makes a really strong build. I flew it on G77R, H165R and H210R motors, it flew great!

What would I do different? As much as I like the AT baffles (yeah I know a lot of folks don't), you need to be careful when flying RMS-Plus motors. The large red cap will block the baffle on ejection, likely resulting in a lawn dart. I forgot to do that on its last fligh! So if you use the baffle, don't use the red cap, just use masking tape to seal in the ejection BP. Alternatively, build without the baffle, so the red cap can eject up & out. If you use CTI motors, this won't be a problem.

All AT kits now come with rail guides and an aluminum retainer, which are both really nice. This will make a great L1 rocket, enjoy the journey!

Thanks for the advice on the reloads. I wasn’t initially planning on flying any, since my RMS 29-40/120 case doesn’t have loads that are convenient for flight at Fiesta Island. The Es aren’t powerful enough for safe flight, the Fs have Hazmat charges, and the Gs take it too high. But if I ever get the urge to put it up on G power in the desert, I’ll be sure to keep this in mind.

 

[jmasterj]

The 24mm and 29/40-120 RMS forward closures use the same small red cap. I haven't had any trouble with those in combination with Aerotech baffles. The high power 29mm forward closure uses a much larger cap that I could see being a blocker.

 

[SolarYellow]

Thanks for the advice on the reloads. I wasn’t initially planning on flying any, since my RMS 29-40/120 case doesn’t have loads that are convenient for flight at Fiesta Island. The Es aren’t powerful enough for safe flight, the Fs have Hazmat charges, and the Gs take it too high. But if I ever get the urge to put it up on G power in the desert, I’ll be sure to keep this in mind.

Yeah, I see the 29/40-120 case as a G motor. Anything less and I'm using the 24/40 or 24/60. Better performance, cheaper reloads, cheaper case if it gets lost.

 

[jmasterj]

Yeah, I see the 29/40-120 case as a G motor. Anything less and I'm using the 24/40 or 24/60. Better performance, cheaper reloads, cheaper case if it gets lost.

Totally agree. I've picked up a few Fs when I'm already paying has because they do have more impulse than the 24mm versions, but I don't see the point of the Es.

 

[smstachwick]

Totally agree. I've picked up a few Fs when I'm already paying has because they do have more impulse than the 24mm versions, but I don't see the point of the Es.

I like them in rockets that can take the Estes E16s. My first reloadable flight was an E23T in my Star Orbiter.

 

[jmasterj]

I like them in rockets that can take the Estes E16s. My first reloadable flight was an E23T in my Star Orbiter.

The 24/40 motors are 33% cheaper, though obviously you then need an adapter. To each his own, though!

 

[smstachwick]

After a couple days ruminating over the UPS updates saying that my package had been logged in Hodgkins, IL (basically Chicago) on the 9th, it finally updated today at 1:20PM. At that time, the kit was in Vernon, CA. Los Angeles. My guess is that it’s being shipped onto a San Diego-based distributor tomorrow and will arrive at my place in Poway at the estimated time.

My excitement has only been growing at this time and it continues unchecked.

 

[FlyBy01]

Poway, work for General Atomics?

 

[smstachwick]

Poway, work for General Atomics?

Negatory. I live with my dad, he’s a network guy for a different defense contractor in the area. I’m a behavioral therapist working with autistic youth and young adults. It suits me better, to be honest.

 

[smstachwick]

The kit has arrived!

When the kit shipped on the 6th, UPS quoted an estimated delivery date of the 12th instead of the 17th or later as predicted by HobbyLinc. While I was skeptical that UPS would hit their mark while the package appeared to be stuck in Illinois, they pulled through and dropped it off on my doorstep late this afternoon.

Although I didn’t truly start with building today, I did open the packaging on camera for my YouTube channel, locate all the components, and transfer all the bagged parts into a resealable gallon bag. I also accepted my girlfriend’s advice to lay a heavy book on top of the instruction sheets and decals. They had been rolled pretty tightly. Everything else appears in order, with no glaring omissions, evidence of shoddy workmanship, or damage.







I was impressed with the size of this kit. I have one made of a Big Daddy kit and a very long 75mm ID tube saved from my youth, but this one exceeds even the length of that one.

I will try to make more progress tomorrow, probably just pore over the instructions and figure out if I can staple them together. I have a friend who displayed some interest in seeing how this kit goes together so I might have a day to show it off and make a dent in the build over the weekend.