Cosmodrome Aerobee Hi

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clairm

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My (finally) completed Cosmodrome Aerobee Hi. I based my model off a slew of newly digitized photos from Life magazine. There are several differences from the ROTW pages and the standard kit, including a longer payload section and the extensive decals, created with the help of Gordon Agnello at Excelsior Rocketry.

IMG_20141002_215126[1].jpg
IMG_20141002_215351[1].jpg

More pictures tomorrow when I can get better light!
 
That's a very nice-looking model. I should mention that if you can give me the flight number, I may be able to look up the overall length including the cylindrical payload extensions. You can reach me by email at petealway (at) aol (dot) com

Peteralway
 
I plan on making all of the pictures (several GB) available sometime since it was a pain to find them all using Time/Life's lousy Web interface. At this point I'm still not sure exactly which flight it is. We have a date the round was created, and a rough idea when the pictures were taken, but no launch date. Of course Peter may be able to figure it out just from the pictures!
 
I flew it on Saturday on an AT G61W-S in the booster and nothing in the sustainer, and cracked a couple fillets on the sustainer. Just bad luck coming down right on top of a bush, I think. According to the Raven on board, the decent rate was 23 fps, which should have been fine, but there is plenty of room for a bigger chute, so I will probably go that way on the 25th. No other damage though. It would have been coming down more slowly if the motor in the sustainer (AT SU F26-9FJ) had actually been used on the way up!

Now for the reason I didn't fly it with two motors. When I went to connect the sustainer igniter to my fancy spring loaded terminal block, the thing fell apart in my hands. DANG! What would be a better choice as a connector at that point? I can't wire the igniter directly to the altimeter, that's way up in the payload section. I'm actually using the external conduits to carry the wiring from the payload bay to the base of the sustainer. I wanted something tool-less but secure, and there isn't much room between the motor tube and the airframe. Nothing can be mounted to the inside of the airframe because that is where the interstage coupler slides in, and the nearest centering ring is deep and inaccessible. I guess I could just twist the wires together and tape them. I'm afraid I would have to replace the wiring every couple of flights after getting torched by the sustainer motor, which would be a royal pain. Any ideas???
 
The photos by J. R. Eyerman were for Life Magazine's 1957 "Space Frontiers" feature(also saw mention of a 1961 issue). I always thought of "Life" as current events, but the only flight ID info I've found online so far was for this 1951 launch:
Launch_Tag........ Launch_JD....... Launch_Date..........LV_Type.............Flight_ID.........Flight..............Apogee
1951-M04........... 2433755.28.......1951 Apr 18..... Aerobee RTV-A-1.....USAF 12.........Aeromed 1........... 61
from Holloman Air Development Center, Alamogordo, New Mexico.

It's hard to tell from your photos, but it appears your fin markings are AF 15. Unless "Life" posted new pics, the ones I have are for AF 12.
Aerobee-Hi-AF 12-detail.jpg
I too have the Cosmodrome kit, but haven't decided what configuration to make it. I've been scaling a fleet based on Semroc's Deci-scale line. I'm not sure how I'll handle the boosters. I will base it loosely on the Cosmodrome design, not sure about gap or electronic staging, maybe booster powered only. Guesstimating the payload dimensions, here's the one I had been working on for the AF 12.
Aerobee-Hi-AF 12-Deci-Scale.jpg

I haven't finalized an Aerobee 75 layout yet, but I'm just finishing up on a 1/10 scale Aerobee 200 HI-STAR South configuration, Infrared astronomy experiments Sept 4/7/17, 1974 from Australian Space Research Institute, Woomera, Australia.
Aerobee 200 HI-STAR South-Variant-Deci-Scale.jpg
 
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The Life pictures show a round build date of 12/56, so I assume the launch took place in early 1957. Yes, the fins are clearly marked "AF 12". Your dimensions of the payload match up exactly with what I calculated, so they must be correct, right? I guess it's possible that there are two different Life photo shoots, but the payload section looks identical in all of them, and completely unlike anything in ROTW.

As far as the Cosmodrome kit, I loved building it, it ended up looking great, and it seems sturdy enough that I'm not afraid to fly it. The main changes I made during the build:

I didn't use the included bungee cords, and instead used twice the length of braided Kevlar
I extended the payload section to match the Life photos
I now had room to locate the altimeter in the actual payload section!
I used half-round plastic of the appropriate size instead of balsa for the conduits, which allowed me to route the wiring for sustainer ignition from the altimeter to the interstage area
I built the sensor shrouds out of styrene sheet, and moved them back to be entirely on the payload section, I didn't want to deal with part of the shroud and conduit being on the nosecone
I had Excelsior create beautiful decals that match the Life photos

Something to look out for: Since the sustainer fins are mostly over an area that includes the interstage coupler, only about the top third of the fin is "through the wall" and attached to the motor mount. As a result, on my first flight, I cracked a couple fillets on landing. I wish I would have done more to get those fins solidly attached to the air frame, maybe cut halfway through the air frame or something. I also plan on using a larger parachute in the sustainer, there is tons of room for recovery gear, but watch out for...

A change that I WISH I had made, would be to get rid of the steel cable shock cord mount. On my second launch the parachute got hung up on the cable eyelet and never made it out of the air frame. In the future I will make sure to push the cable down into the air frame (if possible?) so that the recovery gear is on top of the cable, instead of beside it. The sustainer would have been destroyed, but...

The sustainer motor didn't ignite
The booster motor deployed the booster parachute
The booster stayed attached to the sustainer

...and the whole thing tumbled down in one piece and landed without a scratch.

I guess I'd rather be lucky than good!
 
You're right about the manufacturing date of 12/56. I just noticed the Serial No. on that ID says AF 12, so I guess that that isn't always Flight ID. I had hoped to run across the actual article at some point,but no such luck. It's amazing that with the number of Aerobee launches, how few photo records are around.

BTW: Apogee has plans for an electronics bay, but it has to go in during the build, and adds to the complexity of the construction.
 
A couple other changes I made during construction. First, I built the booster with a short 38mm motor mount, instead of 29mm. It leaves more room for the parachute and an Aerotech G61W with the short delay has worked perfectly so far as a booster motor. Second, I added a shroud and Giant Leap Bell-Shaped Nozzle Retainer to the end of the booster. It doesn't exactly match the prototype, but that huge nozzle is such an iconic part of the Aerobee booster that I had to have one. I'm using an Estes 29mm retainer on the sustainer, so I guess I didn't end up using any of the included retainer hardware.
 
The Life pictures show a round build date of 12/56, so I assume the launch took place in early 1957. Yes, the fins are clearly marked "AF 12". Your dimensions of the payload match up exactly with what I calculated, so they must be correct, right? I guess it's possible that there are two different Life photo shoots, but the payload section looks identical in all of them, and completely unlike anything in ROTW.

As far as the Cosmodrome kit, I loved building it, it ended up looking great, and it seems sturdy enough that I'm not afraid to fly it. The main changes I made during the build:

I didn't use the included bungee cords, and instead used twice the length of braided Kevlar
I extended the payload section to match the Life photos
I now had room to locate the altimeter in the actual payload section!
I used half-round plastic of the appropriate size instead of balsa for the conduits, which allowed me to route the wiring for sustainer ignition from the altimeter to the interstage area
I built the sensor shrouds out of styrene sheet, and moved them back to be entirely on the payload section, I didn't want to deal with part of the shroud and conduit being on the nosecone
I had Excelsior create beautiful decals that match the Life photos

Something to look out for: Since the sustainer fins are mostly over an area that includes the interstage coupler, only about the top third of the fin is "through the wall" and attached to the motor mount. As a result, on my first flight, I cracked a couple fillets on landing. I wish I would have done more to get those fins solidly attached to the air frame, maybe cut halfway through the air frame or something. I also plan on using a larger parachute in the sustainer, there is tons of room for recovery gear, but watch out for...

A change that I WISH I had made, would be to get rid of the steel cable shock cord mount. On my second launch the parachute got hung up on the cable eyelet and never made it out of the air frame. In the future I will make sure to push the cable down into the air frame (if possible?) so that the recovery gear is on top of the cable, instead of beside it. The sustainer would have been destroyed, but...

The sustainer motor didn't ignite
The booster motor deployed the booster parachute
The booster stayed attached to the sustainer

...and the whole thing tumbled down in one piece and landed without a scratch.

I guess I'd rather be lucky than good!


Hey there, looks like a great build. I got my hands on one of these and I am also interested in doing the conduits out of rod, I can't seem to find anything in the correct size. Where did you find it?

Thanks
 
I believe it was Plastruct 90174 HP-8L, which is the longest I could find at 15", so I had to get 6 of them and double them up. The seam in the middle pretty much disappeared. Pretty much.
 
I finally had a completely successful flight of my Aerobee Hi on Saturday at the UROC launch! The key was using a Quest Q2G2 igniter that had been dipped in (David Bachelder) QuickDip and then shaved down to fit in the very tight slot of the F26-9 in the sustainer. Going forward I will always use this arrangement when staging with a Raven altimeter and a 3.7v 130mAh LiPo. I was so excited that everything had worked that I took my attention off the sustainer under 'chute, and really had only a vague idea of where it had come down. It's amazing how high the sustainer went on a lowly F motor. Luckily, a team recovering a different rocket came across the sustainer and brought it to my attention.

I was excited to see the Raven data from the flight, but never got the chance as my next flight (with a different rocket) came in ballistic and destroyed everything, tracker, altimeter, and reload case. Ouch.
 
Congratulations on your successful 2 stage flight.
What did use for the booster motor?
Like you I built mine with a 38mm motor tube in the booster.
Hopefully I’ll get a successful flight this coming April at Argonia.
I’m planning on using an AeroTech G76 or Loki G80 in the booster and an AeroTech G64 in the sustainer.
 
I use Aerotech G61W's with a short delay swapped in for the supplied medium, I don't trust myself to accurately drill a delay grain. All three times, it's been nice and slow but plenty stable off an 8' rail, with staging happening down where you can see it. That being said, now that I've used all three of my G61's I'm considering an H123 for my next launch to get it moving a little faster off the pad. I'll keep using the F26's in the sustainer until I've used all of them as well.
 
Congratulations, Clair, on a good flight! I have used the Qwest Q2G2 igniter along with electronic ignition in my 24 mm reloadable F39 for the second stage of my Standard Missile with good results. I think I've got a photo of your lift-off, although, it is far away for my little camera.

IMG_2905.jpg
 
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