X1.4: A 24mm MD prototype story.

[Andrew_ASC]

Bought a three pack of Aerotech D-15T-7 for the RMS24-40. Figured 1,400ft may be enough to test deployment system before stepping it up to a G-145. Still mulling over whether or not I want to risk fins on an LPR motor. Also bought another CTI G-145. Looool. Apogee darn it get some more in stock!

 

[boatgeek]

If you're concerned about fins staying on, you could make an extra-wide tape thrust ring so your D hangs out a ways and will hit first. You'll have to figure retention, but that shouldn't be awful.

 

[Andrew_ASC]

Thanks to EstesBasher. Cramming for exams and no time for rocket right now.

 

[OverTheTop]

Gotta love matrices

 

[Andrew_ASC]

Filed intent to graduate.

 

[Andrew_ASC]

The chutes and more shock cord are predicted to arrive Friday. Motors shipped yesterday. Antenna shipped today.

 

[Andrew_ASC]

Chutes came in the mail today.

 

[Andrew_ASC]

These top flight thin mill 12” chute fit wonderfully. And I was suprised that 10ft of #500 also fit.

 

[markkoelsch]

View attachment 361655 View attachment 361654 View attachment 361653
These top flight thin mill 12” chute fit wonderfully. And I was suprised that 10ft of #500 also fit.

I knew it would.

 

[Andrew_ASC]

I just retested it with the nomex and coupler from estesbasher and that fit also.

 

[tim cubbedge]

Hey Andrew are you flying that from a tower?

 

[Andrew_ASC]

From a 1010 compatible FaRG.

 

[Andrew_ASC]

Epoxying cord to the coupler and tied two alpine butterfly knots.

 

[markkoelsch]

A farg is ok, but a tower would really be the way to go for this.

 

[Andrew_ASC]

I decided in favor of FARG for economy. It also works with everyone else’s 1010 rail wherever I go to launch this thing. Less equipment to pack. I’ve done towers before for multistage comps, this rocket is for fun lol.

 

[Andrew_ASC]

Sara at Apogee says they have not tested these 24mm egglofter FARG with CTI G-145. ROFL. She called it a big motor oh my. That’s funny. Maybe I should look at alternate FARG?

 

[Andrew_ASC]

Coupler tube epoxied into internally sanded airframe.

 

[tim cubbedge]

Can you still fit your nose cone in it? What about the G145?

 

[Andrew_ASC]

G-145 fits fine I slid that in first. Tested everything before epoxy. I’ll report back in six hours or so. BSI epoxy still wet lol.

 

[Andrew_ASC]

See it fits. Holy F*** it got tight with that coupler. I may need to use Estes wadding like Jim said. Trimming the second butterfly loop off.

 

[rharshberger]

View attachment 361670 See it fits. Holy F*** it got tight with that coupler. I may need to use Estes wadding like Jim said. Trimming the second butterfly loop off.

I still use Estes wadding, usually a single sheet as a "shot cup" to hold a ball of dog barf.

 

[Andrew_ASC]

Trimming off second butterfly loop did it. Man it really needs a good chute rolling.

 

[Eric]

Are you going to wet sand the hole thing to a mirror gloss? What is your final weight, minus motor?

 

[Andrew_ASC]

135 grams with chutes, shock cord, nomex, battery and Telemini. I plan to wetsand but not today.

 

[Andrew_ASC]

Spare G-145 reload in transit.

 

[OverTheTop]

What's predicted accel on this? Might be worth applying some CA adhesive to hold the beeper and terminal blocks onto the PCB a little more solidly.

 

[Andrew_ASC]

93.27 G’s. Hence ditching the GPS and going to old school radio beacon. Motor eject.

 

[Andrew_ASC]

I do worry about the dinky FARG under 77 pound force of thrust.

 

[Eric]

View attachment 361737 I do worry about the dinky FARG under 77 pound force of thrust.

And I would have those FARG's seated all the way against the fins. And they still might explode.

 

[Andrew_ASC]

I stomped on one and it failed where the Elmer’s wood glue touched the outer beams on one outer beam. The wood didn’t split though: only a fail at a glue joint. Not all that confidence inspiring. This rocket might just need its own tower. Lol. Apogee wouldn’t give me a maximum motor they tested it with.​