Time for a scratch build project: a 4" Aerobee 150

krislhull · Oct 5, 2017

When I first got back into rocketry last winter after being on a 13 year hiatus, one of the first rockets I set my eyes on building was a Aerobee 150. For some reason, I have always thought that it was a great looking sounding rocket, and I decided I would build one. After toying with the thought of building one to recert L1, I went as far as ordering 4" tubing from PML, a nose cone from Madcow, custom fins from Mike at Binder Design, and a set of customized decals from Mark at Stickershock back in December.

Around that time, I decided to build the simpler Binder Excel for L1, and the Aerobee project got pushed to the back burner.

That is until now!

After building the MAC Performance ARCAS, I was impressed enough with the canvas phenolic tubing that I decided to order new airframes from MAC, as well as a motor mount assembly. I decided to have him slot the lower airframe for me to save time as well.

Over the past couple of days, I have started to assemble the motor mount by epoxying the upper and mid centering rings in place, and then also adding in the attachment fittings for the rail guides to the forward and aft rings.

Next up was to lay out and mark the locations for the rail guides, and drill the holes in the airframe. After that was done, I slid the motor assembly into the tube, transferred the holes to the brackets, and installed threaded 8-32 inserts into the fittings.

My Aeropack 54mm flanged retainer arrived today, so I laid out the holes, using a 54mm case to hold the retainer in alignment, drilled the thrust ring, and installed the threaded inserts. I then proceeded to assemble the nosecone tracker bay, and mount it onto the nosecone shoulder.

qquake2k · Oct 5, 2017

I like the Aerobee 150, too. I'll be watching this build.

Red Phenix · Oct 6, 2017

krislhull said:
When I first got back into rocketry last winter after being on a 13 year hiatus, one of the first rockets I set my eyes on building was a Aerobee 150. For some reason, I have always thought that it was a great looking sounding rocket, and I decided I would build one. After toying with the thought of building one to recert L1, I went as far as ordering 4" tubing from PML, a nose cone from Madcow, custom fins from Mike at Binder Design, and a set of customized decals from Mark at Stickershock back in December.

View attachment 329502

Around that time, I decided to build the simpler Binder Excel for L1, and the Aerobee project got pushed to the back burner.

That is until now!

After building the MAC Performance ARCAS, I was impressed enough with the canvas phenolic tubing that I decided to order new airframes from MAC, as well as a motor mount assembly. I decided to have him slot the lower airframe for me to save time as well.

View attachment 329504 View attachment 329505

Over the past couple of days, I have started to assemble the motor mount by epoxying the upper and mid centering rings in place, and then also adding in the attachment fittings for the rail guides to the forward and aft rings.

View attachment 329513 View attachment 329506

Next up was to lay out and mark the locations for the rail guides, and drill the holes in the airframe. After that was done, I slid the motor assembly into the tube, transferred the holes to the brackets, and installed threaded 8-32 inserts into the fittings.

My Aeropack 54mm flanged retainer arrived today, so I laid out the holes, using a 54mm case to hold the retainer in alignment, drilled the thrust ring, and installed the threaded inserts. I then proceeded to assemble the nosecone tracker bay, and mount it onto the nosecone shoulder.

View attachment 329509 View attachment 329510

View attachment 329511 View attachment 329512

Nice workmanship. Welcome back to the hobby.

Sent from my iPad using Rocketry Forum

krislhull · Oct 6, 2017

I spent a couple of hours today getting the inside of the lower airframe ready to receive the motor mount assembly by sanding the mating surfaces with 120 grit then wiping down with isopropyl alcohol. I then proceeded to mix up a batch of rocketpoxy, and installed the motor mount, using the forward rail guide location to ensure that the mount was in the proper location. After letting it set for a bit, and after cleaning up any epoxy that smeared along the inside of the airframe, decided to tack the first fin in place. Tomorrow I will tack the other two on and let them cure overnight before starting fillets.

As for projected performance of this bird, based on the finished weight of my similarly constructed ARCUS, I am predicting that the final dry weight will be right around 12 pounds, give or take an ounces. This is mainly because the ARCUS, which is 12 inches shorter, weighs in at 10.3lbs dry, and the fact that the Aerobee is going to be slightly beefier, with a few more pieces.

Rocksim estimates 3,100ft on a J401, which is probably the smallest motor I will fly it on.

As for finishing, I am not sure yet. It will probably be painted to resemble the one that is on display in the Air & Space Museum in DC, or I might do a "what if" scheme.

krislhull · Oct 25, 2017

Over the past week, I've made a little more progress on the Aerobee. After all three fins were tacked in place, I applied the internal fillets over the course of three days. I then applied the external fillets over the following three days.

Yesterday, I started to layout the locations for the conduits. To model the conduits, I am using .25" square basswood dowels. They will be rounded over to simulate the actual conduits, but I will probably do that once I epoxy the strips on, since I need to extend the conduits 2 inches onto the switch band. To do the rounding, I am probably going to order some .25" contour sanding plates that should give me the appearance I am after.

I will probably not get around to securing the strips until next week. I am slowly making progress, though!

krislhull · Nov 4, 2017

Slow progress is being made when I have time to work on it...

A few days ago I finally closed out the fin can when I epoxied the thrust ring into place. Now, I have started to shape the .25" square dowels I have into the conduits and epoxy them to the side of the airframe.

I got the first strip set on today, and I think it doesn't look bad. It's by far not perfect, but it will be hard to tell once the rocket is painted.

I also took the time to take a quick photo of the scale sounding rockets I have that are high power capable: the Estes PSII Nike, my yet to fly MAC ARCAS, and this Aerobee, still in progress. I will have to repeat this photo once the Aerobee is completed, and once I start the LOC Sandhawk I have.

krislhull · Dec 26, 2017

So, after a hiatus of many weeks, I was able to get back to work on the Aerobee.

In the week following thanksgiving, I was able to finishing applying the wood strips for the conduits. These were probably the hardest part of the build, as 1/4" basswood doesn't like to lay perfectly straight when you lay it down! It took lots of patience on my part to ensure they the strips are as straight as possible, and look good.

Next up is the avionics. I took some G10 sheet I had laying around, and I had just enough left to fabricate a avionics sled for the e-bay.

I have chosen to use the same electronics layout I used for my L2 ARCAS, with a MissileWorks RCC3 as primary, a Perfectflite SLCF for backup, and a MissileWorks tracker. Power will be provided by 3 lipo batteries.

At this point, I have basically completed major assembly of the rocket, and I am just waiting on warmer weather to prime and paint it. It might fly naked on its first flight as a result.

krislhull · Jun 20, 2018

Its been 6 months since my last update, and a lot has happened since then, but not much on the Aerobee...

I sent out the RTx unit back to Jim at MissileWorks as it wouldn't pair with my base unit, and it is currently being reprogrammed as I type. I performed the ejection tests last weekend, and verified the charge loads for recovery.

Next up is paint and final touches. I should be able to get it painted over the next week, baring any unforeseen issues or weather.

krislhull · Jun 27, 2018

Well, the Aerobee is all painted and it has received the Stickershock treatment...

First up was two coats of primer, with a sanding in between coats.

I originally painted the booster section in a charcoal grey, but after painting the fins and conduits a anodized bronze color, I felt like the two colors were too similar, and I needed more of a contrast.

I masked off the areas in between the conduits and repainted the charcoal grey a light ghost grey. I was pleased with the look, but I was not too good my my masking, and I had some bleed throughs, and some runs as well.

The payload section was painted white, and the nosecone black.

I think it looks good. Its not perfect, as there are some runs in paint, and areas I slipped when touching up the bleed throughs, but it looks good from 10 feet away. All that matters to me!

krislhull · Jun 27, 2018

Finally, it was time for the Stickershock23 vinyl. I originally ordered these from Mark in December 2016, and have sat on them for the past 18 months. They finally got used!

I still have a couple of small decals to put on, such as the Cp marker, and the labels for my electronics, and then it needs to get a clear coat, but it is done.

Final weight is 10.9 pounds with all of the recovery gear; just half a pound off my original prediction of 11.5 pounds.

For recovery, I have two twenty foot harnesses from OneBadHawk. The drogue is a 30in X Form from TopFlight, and the main is a 8ft Rocketman with a deployment bag.

First flight will be on a larger 54mm J, assuming my order from BalsaMachining arrives before Labor Day. If not, I have a CTI K454 Skid I will put it up on.

Flyfalcons · Jun 27, 2018

Looks great, looking forward to seeing it in September!

krislhull · Jun 27, 2018

I might have something else come September to make a first flight as well! If not Labor Day, for sure October!

krislhull · Jul 5, 2018

Received my RTx unit back from Missileworks today after some reprogramming and got it reinstalled on the sled. The final component needed for this bird came in as well today, the Rocketman 8ft main and deployment bag. Everything is all set for the next launch, which is looking like September at this time, if the weather in the Tri Cities is greater than 95 degrees next week.

krislhull · Sep 3, 2018

Well, Tri Cities Rocketeers' Sod Blaster was a great success for me! After waking up at O dark thirty, and driving nearly 4 hours, I arrived at the sod farm north east of Pasco and set to work prepping the Aerobee for its maiden flight. I selected a K456DM to use for this flight, and it was both my first 54mm motor, and my first K motor.

The first flight was picture perfect to 3,688ft. The 8ft Rocketman chute worked great, and is the perfect chute for this rocket. For this first flight, I didnt use the deployment bag, as I had never used one before, and didnt want to add any extra complexity to this first flight. I flew a deployment bag later in the day on my MAC ARCAS, and will use on on this rocket for all future flights.

On Saturday, I prepped it again, and flew it on my largest motor to date, a K850DM (Thanks Mike at Bay Area Rocketry for the motor, and David R for delivering it to me!). This motor put me over the mile mark for the first time. Final altitude was 5,462ft.

In the next year or so, I would love to see what a K270 and a L1000 will do to this rocket. I imagine it will be quite the performer!

Bat-mite · Sep 3, 2018

Great shots! And it looks like you had a pretty easy recovery. Congrats. Looks like a great field, too.

Andrew_ASC · Sep 3, 2018

Nice Aerobee! Epic flight.

krislhull · Sep 3, 2018

Bat-mite said:
Great shots! And it looks like you had a pretty easy recovery. Congrats. Looks like a great field, too.

Thanks! It is a great field to fly from! The main circle we were launching from was freshly plowed, so the ground was way softer than it normally is. We had one flyer core sample an 8ft tall fiberglass rocket, and buried about 5ft of it in the ground. He dug it up, and found it to be mainly undamaged. I believe he said he needs to make a new avionics bay, and thats it.

Andrew_ASC said:
Nice Aerobee! Epic flight.

Thanks! I am looking forward to seeing what it will do with even bigger motors!

Andrew_ASC · Sep 3, 2018

Might want to AeroFinSim such a beautiful rocket before stuffing the largest longest motor into it if your into theoretical predictions of when fins rip off by harmonic vibrations for flutter reasons.

DM1975 · Sep 3, 2018

Very cool!!!

rharshberger · Sep 9, 2018

How did I miss this build thread Kris, great job on the rocket and its flights. I am planning the build for my 3" Madcow version, thinking Nike-Aerobee 150 (not to scale really as the booster will be slightly larger in diameter due to easily available airframes, 4" booster and 3" sustainer, actual booster was only slightly larger diameter than sustainer).

grouch · Sep 9, 2018

Super cool Kris. I am a sucker for anything sounding rocket but the Aerobee is my favorite. The DM looked awesome!!!

Time for a scratch build project: a 4" Aerobee 150

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