BMS 29mm School Rocket Build Thread

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TigerHawk

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I've launched my 24mm 3" school rocket on the Estes E12-4 BP motor twice and it was marginal at best. Both launches veered badly as soon as it left the launch pad rod. Have launched it with E20 and F44 motors for great launches and recoveries.
 

Back_at_it

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First flight on mine was a relatively mild E30-4. Low flight but plenty of power off the pad. Next was an F44 then up to F67. It’ll take pretty much any F motor you care to run.
 

lstmysock11

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The standard length 29mm version with a reasonable finish should weigh under a pound - probably close to 12 ounces - which should allow any Aerotech F or G single use 29mm motor plus a bunch of reloads. On a still day off a launch rail you could do a 300 ft “school yard” flight over an adapted Estes BP E12, so just about any Aerotech single use 24mm E and up should work. Oddly, the big Estes 29mm BP motors are probably a bit too heavy for the available thrust - Thrustcurve shows it a bit too slow off the rod.

For fun, low but high enough to be interesting flights the 24mm Aerotech E20-4W would be a good choice - no hazmat shipping and discount price of around $21 for a two pack. With the additional payload bay you’d probably need a little more oomph - Aerotech Economax F44-4W should work. The Estes #9753 24/29 Adapters work great with both “rimless” BP motors and AT motors with integral thrust rings.


Would this also work with the 29mm version of the Estes DoorKnob?
 

lstmysock11

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Do you have any experience with Rocketry?
Just a little from years ago with just Low power rockets. Never used a motor retainer like this, always just had the simple motor retainer like the one they use on the 24mm kit
 

Scott_650

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I've launched my 24mm 3" school rocket on the Estes E12-4 BP motor twice and it was marginal at best. Both launches veered badly as soon as it left the launch pad rod. Have launched it with E20 and F44 motors for great launches and recoveries.
Edited.
Hmmm…both my 24mm SRs fly great on E12s - not too high but straight. I tend to build fairly light - my first one doesn’t even have papered fins. But I don’t launch when there’s much wind, our club field is on a working farm so going into the corn or beans is no fun. The E20, F44 and F32 are about perfect for it - I use my Chute Release with the F motors to keep the post recovery walking down a bit 😉

I do launch off the club’s 1010 rod using rail guides - that can make a difference with lower powered motors. YMMV.
 
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lstmysock11

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waltr

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I flew my extended 29mm MM school rocket on an Aerotech F39T with 6sec delay (24/40 reload in an Estes adapter) to about 800 feet and 19m/s off a 6 foot 1010 rail. Great first flight.

For single use F42T, F67W (as used above), F44W, F52C and more would fly well.

Run sims in Open Rocket to get idea of Rail speed and apogee.
 

lstmysock11

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teepot

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The 2 I built, one was the regular one and one with the extra tube. Both were motor eject. You could put in an Av Bay if you wanted to do dual deploy. The Z clips the kit comes with work fine. Those two kits were the first I had seen with the clips. Now that is what I use on most of my rockets. I use the Estes and Aeropack retainers when needed for a specific rocket.
 

waltr

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My extended school rocket is the longer main tube without the payload bay.
I did add a 33mm stuffer tube to reduce the volume for motor ejection.
Total weight is around 500 grams.

Did get the payload bay but haven't put it on yet. Planning some logging electronics for it.
 

lstmysock11

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Okay with the BMS 29mm what size shute? With the extended bay. They also sell the swivles and quick release. Guessing for this one the smallest size. What about for the doorknob and a LOC IV?

 

Joekeyo

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Here's mine. 24mm & not the extended version. The overspray is supposed to be a galactic look. Use your imagination. Flies ok on E12. Looking forward to flying it on F12.
20211128_081620.jpg
 

Alan R

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Thank you, What did you put in the extended bay? Did you make it into a ebay? Use some kind of eletronics to help deploy the parachutes? Sorry for all the questions. Trying to absorb all the information I can find.
There's no payload bay. Nothing in there. It's just extra length body tube. I did it because I liked the look of it more and I already have a short 29mm rocket.
I just use a chute release also on most F+ flights.
LOC Micro Magg:
IMG_0357.jpg
 
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lstmysock11

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There's no payload bay. Nothing in there. It's just extra length body tube. I did it because I liked the look of it more and I already have a short 29mm rocket.
I just use a chute release also on most F+ flights.
LOC Micro Magg:
View attachment 491835
What size parachute for a rocket that size? Would the same size also work on the doorknob? Like someone else said about sharing parachutes between rockets with a quick release.
 

Alan R

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What size parachute for a rocket that size? Would the same size also work on the doorknob? Like someone else said about sharing parachutes between rockets with a quick release.
Size of the rocket doesn't matter. It's the weight that matters. This School Rocket is only about a pound. I think I used a large plastic Estes chute, or a nylon with no spill, probably 18", both on low chute release.
 

lstmysock11

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Size of the rocket doesn't matter. It's the weight that matters. This School Rocket is only about a pound. I think I used a large plastic Estes chute, or a nylon with no spill, probably 18", both on low chute release.
Perfect looks like the doorknob also comes with a 18" parachute and says it weights 10 ounces. Of course I am doing the 29mm upgrade kit to it. Will make sure to weigh it when complete but how much more could it gain from better fins.

So I should be able to share parachutes between at least two rockets.

Do you use some sort of release system for the parachute that releases the parachute at a set height when coming down
 

Alan R

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So I should be able to share parachutes between at least two rockets.

Do you use some sort of release system for the parachute that releases the parachute at a set height when coming down
I see you really are new here.
People always swap parachutes around. A bit of wind? Or small field? Use a smaller chute.

As for your 2nd question, most people use Jolly Logic Chute Release. Just search the forum and you'll see lots of info on that

516R9IaacDL._AC_SX466_.jpg
 

Alan R

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Perfect looks like the doorknob also comes with a 18" parachute and says it weights 10 ounces. Of course I am doing the 29mm upgrade kit to it. Will make sure to weigh it when complete but how much more could it gain from better fins.
If you're really new to rocketry, why are you upgrading to 29mm right from the start?
A lot of the questions you're asking here could be answered by yourself with just a few actual flights.
Why not just go buy, build and fly any good 24mm (D,E) kit. You will gain lots more knowledge on your own than we can impart to you on the forums. After you fly that a few times, you will have a much better idea of what you want to do with a higher-flying 29mm rocket.
 

waltr

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In my 500 gram school rocket I used a 24 inch Topflight nylon chute wrapped in a 9 inch Nomex blanket. This gives a decent rate of around 6.5m/s (21f/s).

Going with the 29mm school rocket allows later options. An Estes 24-29 adapter allows any 24mm motor. Also I much prefer plywood fins over balsa for a rocket this size.

Picture and OpenRocket file attached.
 

Attachments

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lstmysock11

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If you're really new to rocketry, why are you upgrading to 29mm right from the start?
A lot of the questions you're asking here could be answered by yourself with just a few actual flights.
Why not just go buy, build and fly any good 24mm (D,E) kit. You will gain lots more knowledge on your own than we can impart to you on the forums. After you fly that a few times, you will have a much better idea of what you want to do with a higher-flying 29mm rocket.
Yes I am rather new but I have done a number of LPR rockets in the past. Think might start with https://www.mach1rocketry.com/bt20-rockets , Either the BT20 or 50. Rather inexpensive and can use the smaller motors. Guess I wanted to fly something that you have to build the motor mount setup instead of all being the same tube. Thanks for answering my questions.
 

lstmysock11

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In that case, just get a 2" or 2.6" diameter rocket.
What kits would fit that bill or what company should I look at. I had just been looking at Mach 1, Just not sure what fits that size and never built a fiberglass rocket before.
 

Rocketless

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I flew my extended 29mm MM school rocket on an Aerotech F39T with 6sec delay (24/40 reload in an Estes adapter) to about 800 feet and 19m/s off a 6 foot 1010 rail. Great first flight.

For single use F42T, F67W (as used above), F44W, F52C and more would fly well.

Run sims in Open Rocket to get idea of Rail speed and apogee.
Did you use the whole extension for the 29mm School Rocket?
If so, where was the new center of pressure?
 
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