4 inch BSD Horizon

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Feb 2, 2003
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For Christmas, I got the 4” BSD Horizon. This kit is great! The rocket features a 4 inch plastic nosecone, strong 4 inch airframe tube (kind of like LOC tubes), 38mm MMT with 29mm adapter, 3/16” plywood fins, tubular nylon for shock cord, eyebolts for attachment of shock cord, 30” chute, launch lug AND rail buttons, vinyl decals, and blind nuts and hardware for motor retention. Construction was fairly easy. It was just like building a giant size Estes kit. I first assembled the MMT tube, which involved gluing the CRs to the MMT. Next I installed the blind nuts and the eyebolt. I forgot to get a picture of this assembly before I glued it in place. Sorry guys! Next, I hand cut the fin slots. I test fitted the fins for a proper fit and they fit well. I took the fins out and epoxied the MMT in place. When I first got the kit, the CRs and the bulkhead were too tight of a fit to insert them into the rocket, so I sanded them. I sanded the bulkhead perfect, but I sanded the CRs a little too much and they were too loose to stay in place while the glue dried, so I took a small screw and screwed the CR in place temporarily until the glue had set. Next, I took out the screw and epoxied the fins in place. After that, I put the eyebolt into the bulk plate and epoxied the bulk plate into the tube coupler, which was also a little tight of a fit. I have decided not to glue the tube coupler into the payload tube yet until I decided whether or not I will attach threaded rods so I can use the payload bay as an altimeter bay. Next, I tied the shock cord in place. The shock cord is very long, about 18 feet long! After that, I installed the rail guides. I put the aft rail guide in the hole where the screw was that held the CR in place. I put the other rail guide 6inches down from the top of the airframe tube. The only thing left to do with this rocket is pour glue fillets, pour glue over top CR, finish payload/altimeter bay, epoxy rail guides in place, paint the rocket, and apply vinyl decals. I will fly this rocket on a H165R for its first flight. This is a great rocket and I recommend it for anybody who wants a simple, yet large rocket to build. If built properly, this is a great L1 and L2 certification rocket! I love this rocket and I can’t wait to launch it!
It is a great rocket and a great choice for level 1.. i've built two..

Both the 3" and 4" versions.. would like to build the 5.5" version some day...
I've got 2 myself. I thought the originial kit was so good I modified my second one to take 7 29mm motors.



Eric F.
very cool rocket, it reminds me of my EZI-65

3" mount? very cool. that thing is going to go.
Trust me - Eric F.'s "Event Horizon" really SCREAMS on his 7x29mm cluster!
"Event Horizon" has just gone to the top of my "must build" list for our elementary school rocket club....

I do have a question...what type of launch system are you using to ignite?
My first 2 attempts failed because I couldn't get enough juice to the igniters. The 75' - 100' extension cords we use to reach the pads took too much of a power drop.

What I needed to do is to place a battery (lawn tractor) at the pad. I incorperated an old Ford starter relay to trigger it. The launch pad leads would go to the relay to trigger it and the juice would only have to travel maybe 3 feet.

When I launched the Event Horizon all 7 popped at the same time.

Check out the launch pics at:


I'll shoot a picture of the "Battery Box" and post it.
I just completed a relay launch system.... 12v + 1/2 a kabillion amps are all 1.25 feet from the pad.....

We may actually build this yet this year....
Be careful with putting 7X29mm motor mounts in a 4" frame. normally you would make the centering ring with the holes cut just big enough to fit the motor mount tubes through. Well, there isn't enough room to cut holes that big without your centering ring falling apart. I had to cut the holes the same diameter as the I.D. of the motor tubes and had to stack them as I glued them.


I wanted 3 rings to add strength so I added and upper level.


Eric F.
Originally posted by Rocket Flier VB
I've got 2 myself. I thought the originial kit was so good I modified my second one to take 7 29mm motors.
see images above

Eric F.

Wow, cool flames!:)
I flew my Horizon yesterday on a H128 at the MC2/HARA.SMART launch in Manchester TN. I modded mine so that I could put electronics in the payload bay. I set up an apogee charge just incase motor ejection didn't work. Liftoff was great, althought is tilted a few degrees from verticle (which was odd because it came off a rail). The H128 is a nice motor! :D The rocket got to apogee and strted to tilt over. Nothing. The rocket fell about 100ft, still nothing. I was strating to get more worried. It just kept falling and nothing......nothing........pop! One of the charges went off and it finally deployed a couple hundred feet off the ground. Well, it wasn't a full deployment. The chute was tangle and it hit harder than I would have liked. The damage was: boster tube came unrolled a little at the seam just above the fins (I will just fill it up and repaint that part), the very bottom of the tube was dented a little (no big deal) and the nosecone and the payload bay suffered cosmetic damage. Out of the whole 1mile by 1 mile sod farm, it landed on the only part without grass, it was an area of sand or something. The altimeter was beeping out 480' which was WAY lower than expected. I expected at least 800'. Chuck Andrus and I have concluded that the apogee charge went off at some point but failed to seperate rocket. When the rocket finally seperated, it was because of motor ejection. he medium delays were way too long. Instead of the 7 second that we expected, we got about 10 seconds. When the parachute finally deployed, one of the shroud lines got wrapped over the canopy not allowing the chute to inflate. As the rocket fell, it rotated around in circles, further twisting the lines. The chute didn't stand a chance. This could have been prevented had I put the shroud lines in the chute when I folded it. I had them this way before the launch but I wanted to repack the chute to get it out of its folded state sop that it would open easier, but I was in a hurry and forgot to fold the chute with the lines in it. I don't have pictures of the crash yet because the rocket and the camera are at Chuck's house. I do however, have a picture of me, Chuck and the Horizon a few days before the launch. I have learned a lot from this launch and I will take things more seriously next time. There is a lot bigger step from Gs to Hs and so on. I will be better prepared next time. I also plan to have the rockets 90% flight ready before leaving the house to go to the launch becaus ewe encountered a lot of things that slowed us down. The motor adapter was too long for the bolts I had and the motor retention hook things only worked if you had a 38mm motor installed, the wiring for arming the altimeter had to be changed a little, and a few other minor things.
nice paint job, I always put lots of BP in the ejection charges, if you have a long enough shocord it couldnt hurt, and if it does, it is much better to have too much BP than to little.
That's too bad on the damage, havoc... but you just learned my #1 rule in rocketry (which I learned from Sonny Thompson): blow it out or blow it up! :D

Let us know how the rebuild goes!
Next time it will have more BP and a "short" delay compared to the "medium" delay.
Hope all of you enjoyed the pictures. Here is the final one.

Great pictures!!!!

Havoc the medium delay in the H128 is 10 seconds... you'll need a short delay with that bird and motor combo.

Do you know what your liftoff weight was or loaded weight without the motor..? Would think you'd get at least 800 feet unless your altimeter mods really added some weight..

Congrats on the flight, didn't go perfect but it went, and the learning is the fun part too...
I guess I still had the mid power medium delays in my mind when I simmed it. I thought medium was 7 sec not 10. Rocket was about 4lbs 2 oz. fully loaded. Apogee was supposed to be about 900' according to Rocksim. Next time it will fly on an I motor. An H is slight underpowered. Notice it went off the rail slightly less than vertical. Thanks for the replies!