Question re: G-64 2 grain nozzle throat diameter

[J Blatz]

I tried the AeroTech website, but all that is shown is that the nozzle is part #01350 (ie, undrilled, as the one that came with the reload kit was).

Can someone advise me of throat diameter? I can fit a 1/8", but not a 9/64" through the nozzle on mine and would just like to double check that this is the correct nozzle throat.

 

[GregGleason]

You can contact AeroTech via email. I have done that in the past with such questions. That way, you know you are getting the right answer.

Greg

 

[mikeyd]

The G64 nozzels appear to be cast not drilled, and many times have plastic flashing still covering the hole. I just poke a pencil tip or other shop object through it, and load it up as normal.

 

[jimzcatz]

Every G-64 I have ever used in the past was a single grain. Did they re-design the load to a 2 grain?

 

[mikeyd]

Yes, a video showing the build, and the nozzle flashing can be seen on the Apogee website here. https://www.apogeerockets.com/Advanced_Construction_Videos/Rocketry_Video_19

Make sure to read the instructions! I just watched this video, and looks like he installed the aft o-ring in the wrong spot! Look at Fig9 of the instructions!

 

[Johnly]

Every G-64 I have ever used in the past was a single grain. Did they re-design the load to a 2 grain?

The re-design occured several years ago, perhaps over 5. The new reload uses 2 30gram propellant grains, which means that it can be shipped USPS and avoid HazMat charges.

John

 

[CarVac]

Surely it changed the thrust curve though, to have more peak thrust and to regress more. Which version do the thrust curves represent?

 

[GregGleason]

Yes, a video showing the build, and the nozzle flashing can be seen on the Apogee website here. https://www.apogeerockets.com/Advanced_Construction_Videos/Rocketry_Video_19

Make sure to read the instructions! I just watched this video, and looks like he installed the aft o-ring in the wrong spot! Look at Fig9 of the instructions!

I noticed that mistake, too. Hopefully people will use the instructions.

Greg

 

[GregGleason]

Surely it changed the thrust curve though, to have more peak thrust and to regress more. Which version do the thrust curves represent?

Yes it did. You can see that in the thrust curves.

Greg

 

[jimzcatz]

Ahhhhhhh, suffice it to say I have some old loads!!

 

[atticus]

Here's a link to the RCS drawing for nozzle #01350:

https://static.fw1.biz/templates//170652/myimages/rcs_01350_nozzle_dwg.pdf

It shows the undrilled throat to be 0.141" (+/- 0.002")
(9/64" is 0.1406" so it should go or almost go with the minus tolerance.)
They do say throat drilling can be done with a carbide bit.

 

[shreadvector]

•G64W 2-Grain Instructions (978k)

https://www.aerotech-rocketry.com/c...tions/RMS-29_40-120/rms_29_g64_bif_20032b.pdf

Instructions are copyright 2006. it is now 2012. Certification was not altered because the change in design fell within the parameters that did not require re-testing and re-certification.

NAR data sheet is for the old single grain 62.5 gram propellent version. It would be nice if the NAR would update the data sheet, but that should be done when they do (or did) the required periodic retesting.
https://www.nar.org/SandT/pdf/Aerotech/G64.pdf

Send them an e-mail to remind them they need to do this. They did update the data sheets for the single use E15 which is now the same as the E20.

Ahhhhhhh, suffice it to say I have some old loads!!