Discount Rocketry Crayon Parts Kit Build

[dhbarr]

Do you have one of the Ralphco or Fantazia ones to compare it to?

 

[mikeyd]

And here are the four Ralphco sizes I am aware of note the large Ralphco is smaller diameter but same height as the greatbigstuff shown in last post above

 

[OhioFlyer]

So I finally got around to wrapping this build up. Added a lot of nose weight with be final NC weight being a hefty .97lb. Used an automotive Christmas tree fastener though the top of the NC to give the epoxy/bb slurry something to grab onto. Went with Rail Button Supply House anvil rail buttons to clear the top and bottom bands (ultimately could have got away with some 1/8" spacers but they look cool so why not), Aeropack retainer, riveted Tailcone, and swapped the eyebolt on the NC for a forged one.

All in all a fun build that I plan to send up with a J270W 38mm DMS with a projected alt right around 3kft. Will be running a JLCR to keep it from drifting too far.

 

[OhioFlyer]

Sim File for anyone who might be interested

 

[OhioFlyer]

Finally flew it today on a J270W at the WSR703 launch today for my L2 cert. Nice flight up to 3527ft and used a JLCR to deploy the main at 500ft.

 

[Rocketless]

Finally flew it today on a J270W at the WSR703 launch today for my L2 cert. Nice flight up to 3527ft and used a JLCR to deploy the main at 500ft.


View attachment 510457

What was the delay and actual time from burn out to apogee?

 

[Scott_650]

What was the delay and actual time from burn out to apogee?

I’ve simmed the very similar 4” crayon rocket I used for my L1 (I’ll probably reuse it for my L2) on the AT J270W - my results show it needs at least a 10 second delay though I’d probably go with 12 seconds if I was using a Chute Release, better a second or two after apogee rather than before - but that’s my preference.

 

[OhioFlyer]

My delay was early at 8 seconds which is what my sim suggested. If I were to fly the same motor again I'd go with 10 seconds. Apogee was also 527ft higher than sim'd.

Will be flying it at the next launch on a J420R and will err on the high side of whatever the sim spits out for delay.

 

[Rocketless]

My delay was early at 8 seconds which is what my sim suggested. If I were to fly the same motor again I'd go with 10 seconds. Apogee was also 527ft higher than sim'd.

Will be flying it at the next launch on a J420R and will err on the high side of whatever the sim spits out for delay.

I will launch mine with an Eggtimer apogee with motor back up at 12 seconds then,
Thanks!

 

[OhioFlyer]

I will launch mine with an Eggtimer apogee with motor back up at 12 seconds then,
Thanks!

If you've got the apogee you can always leave the delay grain undrilled if you have any concerns. I also posted my sim file of you wanted to play around with it. Just override the mass/cg to match your actual measurements.

Best of luck and be sure to report back!

 

[Arnie]

I have one of these pending a build.

FAO Schwarz had a 5 incher too.
Probably same manufacturer.
View attachment 494849
Maybe one of these days I'll get to work on this.

Sounds like it sucks to be FAO Schwarz

 

[OhioFlyer]

Flew my Crayon again today, this time on an AT J420 Redline and with my JCLR set to 400ft. Great flight with apogee at 3671ft.
View attachment 277660383_925887854755618_8260166856942721305_n.mp4

 

[OhioFlyer]

I280DM - 3100ft apogee
View attachment 277834570_374279838042608_6329082813038733713_n.mp4

 

[Rocketless]

Here is a $3 Facebook find
Heavy cardboard body tube, body tube is 26 and 1/4 inch tall, 2 and 5/8 inch outside diameter, says copyright 1993 Binney & Smith Inc.
A Public Missels nosecone (now from LOC) with the shoulder sanded down fits perfect,
I am going for a 38 mm motor mount in this one

 

[OhioFlyer]

Here is a $3 Facebook find
Heavy cardboard body tube, body tube is 26 and 1/4 inch tall, 2 and 5/8 inch outside diameter, says copyright 1993 Binney & Smith Inc.
A Public Missels nosecone (now from LOC) with the shoulder sanded down fits perfect,
I am going for a 38 mm motor mount in this one

Nice! Look forward to an update once you get it built.