Gorilla 6" motor

[jimzcatz]

Why are the grains so thinly cut? For motor performance reasons, or are there shipping regulations that come into play for grains this size?

Shipping, as posted earlier in this thread. Requires no special hazmat shipping other than 1.4C

 

[butalane]

Does anyone know the dry weight of the hardware? The BH looks massive.

What is the distance of those pin holes to the case edge?

 

[FredA]

Alex -- what's with the trust curve in that pdf you posted -- "98/11000 Curve"

 

[GRIFFIN]

Alex -- what's with the trust curve in that pdf you posted -- "98/11000 Curve"

I was wondering the same thing

 

[jimzcatz]

Just to be clear, epoxy is applied to all end surfaces except the two exposed. Is that correct? Just checking my understanding.

 

[FredA]

So these are essentially made with triple tube sets....three layers of cardboard when you are done?
The OD of the propellant itself is no longer 5" as in a usual motor? What is it?

Gotta say I'm surprised by the boat glue -- would have expected R45, but I guess it makes sense since that's not available to everyone......

 

[CarVac]

So these are essentially made with triple tube sets....three layers of cardboard when you are done?
The OD of the propellant itself is no longer 5" as in a usual motor? What is it?

Gotta say I'm surprised by the boat glue -- would have expected R45, but I guess it makes sense since that's not available to everyone......

It shouldn't need to be high temperature; it only has to inhibit burning of those surfaces.

 

[gorillamotors]

Just found this posting from Alex.

There are a total of 15 grains for each motor. Three (3) grains are glued together and to the mini liner making 5 grains total. They are cut this way to allow shipping under SP10996 1.4C restrictions allowing me to ship two 'O' motors for one $27.50 hazmat fee. The cost of a single 'O' motor sent out as 1.3c is around $1000 hazmat fee I believe.

I recommend the use of West Systems epoxy with the slow curative.

Propellant weight for the sparky is around 38# and motor weight around 75#. I will be static testing two more 'O' motors this Saturday: a blue one and a white bates one. I have already tested and will be sending a long burn to TMT for certification.

Sorry about the 98/11000 graph on the instructions. I need to update that soon.

Charles Ogino of https://www.carolinacompositerocketry.com/main.sc has a MMT for Gorilla 6" motors. Call him.

 

[FredA]

Jim,

Kudos to the innovative thinking to get the Hazmat shipping costs under control.
Great idea.

 

[jimzcatz]

Jim, do you have any price estimates yet??

 

[bobkrech]

Why are the grains so thinly cut? For motor performance reasons, or are there shipping regulations that come into play for grains this size?

DOT-SP 10996 is the reason why the reload can be shipped as a 1.4C instead of a 1.3C. The special permit requires that each individually packaged propellant grain can weigh not more than 1.4 kg and not more than 5.6 kg of the individually packaged propellant grains can be shipped in one outer box. Four boxes are required to ship the 15 propellant grains for this motor. The shipment must include a copy of the special permit and the authorization. Here's mine.

Bob

 

[gorillamotors]

Jim, do you have ane price estimates yet??

The hardware is $1950 and the reloads are $1750 (at least right now the sparky is).

 

[butalane]

It shouldn't need to be high temperature; it only has to inhibit burning of those surfaces.

Thats sort of contradictory: in order to effectively inhibit it needs to withstand high temperature.

I was thinking the same thing as Fred...

 

[CarVac]

Thats sort of contradictory: in order to effectively inhibit it needs to withstand high temperature.

I was thinking the same thing as Fred...

Dunno about that. When epoxy reaches its glass transition temperature, it softens. What matters isn't its strength, but even when liquid it has a heat capacity and a heat of vaporization, as well as a lack of oxidizer embedded in it, which will inhibit the propagation of flame. Similar to how grease can inhibit the face of a grain, while having zero intrinsic strength.

Additionally, the faces which are sitting flat against each other are going to stay that way even if the epoxy between them softens, because the epoxy on the outside of the grain next to the mid-liner will hold them together.

 

[butalane]

Dunno about that.

I do.

Similar to how grease can inhibit the face of a grain

You inhibit your motors with grease?

 

[daveyfire]

I'm excited to see the results of the blue and white tests!

 

[jimzcatz]

The hardware is $1950 and the reloads are $1750 (at least right now the sparky is).

Thanks!!!

 

[gorillamotors]

Here is a corrected pdf file along with eng & rse files. I have never uploaded these here so I hope they get loaded right!!

 

[3stoogesrocketry]

Gorilla Rocket Motors


https://www.youtube.com/watch?v=caq_UmlKjcM White O 5000
https://www.youtube.com/watch?v=MBX8YBahb-8 White O 5000 nozzle view
https://www.youtube.com/watch?v=enEQrf6VT80 Blue O 6500


Eric

 

[dixontj93060]

OOOOOMMMMMMGGGGGGG !!!!!!!!!


Sent from my iPhone using Rocketry Forum

 

[JDcluster]

Probably why we're getting so much snow.
The earth's orbit has been shifted because of these static tests :wink:


JD

Gorilla Rocket Motors


https://www.youtube.com/watch?v=caq_UmlKjcM White O 5000
https://www.youtube.com/watch?v=MBX8YBahb-8 White O 5000 nozzle view
https://www.youtube.com/watch?v=enEQrf6VT80 Blue O 6500


Eric

 

[gorillamotors]

Here is a link to my O motor static tests.

https://www.gorillarocketmotors.com/newmotortests.html

 

[alexzogh]

I'm building the first motor in preparation for thunderstuck at the beginning of April.

Significantly easier to build the grains then it may sound. Takes about 5 minutes each. I used a few old CD's on the top grain before putting a weight on top instead of cutting a custom disk. Worked out fine

Someone asked what the diameter of the grains were. They are just about 5" each.

 

[Zeroignite]

Sweet mother of Jebidiah...

 

[alexzogh]

Almost done building the motor. Had to do some finishing touches as the 6" PR fiberglass tube is slightly smaller then the case. Easily solved with a flapper sander.

 

[CarVac]

Almost done building the motor. Had to do some finishing touches as the 6" PR fiberglass tube is slightly smaller then the case. Easily solved with a flapper sander.

Don't breathe!

 

[Zeroignite]

That borehole is so big. I think it wants to eat me.

 

[alexzogh]

Motor was launched at Thunderstruck yesterday - perfect launch, great motor. I uploaded a slow motion video of just the beginning for jim.

[video=youtube_share;Ibdxwx8gCoA]https://youtu.be/Ibdxwx8gCoA[/video]

You can see the whole flight by going to the link in my signature, or going to the thunderstruck thread.

 

[cwbullet]

Scorched Earth?

 

[chadrog]

Scorched Earth?

As well as scorched ground support equipment!