Black powder?

[WrRider]

I built a katana jr, still need to paint it. I have never done D.D. I have everything I need except the Black powder, iv called every place around me that I can think of and checked online but can not find any 4f powder however bass pro did have 3f. I live in the southern California riverside county. Dose anyone know where I can find some?

 

[cls]

I built a katana jr, still need to paint it. I have never done D.D. I have everything I need except the Black powder, iv called every place around me that I can think of and checked online but can not find any 4f powder however bass pro did have 3f. I live in the southern California riverside county. Dose anyone know where I can find some?

Go to the launch and ask around. I'm sure you'll get some bonus, fresh eyes and good advice about your dual deploy setup.

 

[Titan II]

and checked online but can not find any 4f powder.....

https://www.buffaloarms.com/goex-4f-black-powder-for-use-a-goex4f.html

https://www.powdervalley.com/product/goex-black-powder-ffffg-1/

and others.....

 

[Buzzard]

If you just need a bit. Hazmat free, but at a higher "per unit" cost.

https://www.buyrocketmotors.com/ejection-charge-kit-12-pack/

 

[WrRider]

https://www.buffaloarms.com/goex-4f-black-powder-for-use-a-goex4f.html

https://www.powdervalley.com/product/goex-black-powder-ffffg-1/

and others.....

Thanks. I orderd from Powdervalley. Buffalo has a 5lb minimum. I do plan on going to a launch, now I can pre test my charges then have someone check my setup before I launch. I would love to try a G12 motor

 

[Art Upton]

A G12 motor needs an almost sub-min diameter rocket to fly on. Needs Very Very Low weight or Trust Vector Stability, or be an RC Rocket Glider using wings for lift.

 

[WrRider]

A G12 motor needs an almost sub-min diameter rocket to fly on. Needs Very Very Low weight or Trust Vector Stability, or be an RC Rocket Glider using wings for lift.

Thanks. That makes sense I haven't dine any calculations for it yet but with such a long burn time max thrust must be low.

 

[lr64]

James Yawn has experimented with smokeless powder:
https://www.jamesyawn.net/ejection2/index.html

There are some alternatives which may be against the rules to discuss here.

 

[Zman1961]

A G12 motor needs an almost sub-min diameter rocket to fly on. Needs Very Very Low weight or Trust Vector Stability, or be an RC Rocket Glider using wings for lift.

WrRider, Art Upton is VERY correct. A basic rule of thumb for the thrust to weight ratio is to divide average thrust in Ns (the number on the motor, in this case the "12" in G12) by 22.5, the result is the maximum safe rocket lift-off weight in pounds. In this case, 12/22.5 = 0.53 pounds, or about 8.5 ounces. The long burn won't help. This does not not apply to high drag rockets like the spinning type, they need higher average thrust. You should ALWAYS do simulations, especially with high power, using ROCSIM, Open Rocket (free), or the ThrustCurve (free) web tool. I like ThrustCurve. You put in certain basic data about the rocket and launch conditions, and it will use its library of commercial motors to give you a great reference table of usable and nonusable motors of the specified diameter along with a lot of other useful data, like a suggested delay time and predicted elevation AGL. The table can be printed as a PDF in its native format or as a spreadsheet.

 

[tfish]

The G12 has an initial thrust of 32 n/S - 7 pounds.

5 to 1 thrust to weight = 1.4 pound rocket..
..yes, as small a dia and as light as possible..is better.

Tony

 

[cls]

For a G12 machine... I used Estes BT55, two 18" lengths, and ogive nose cone. 3 trapezoid fins. Wraps of masking tape for friction fit of Motor. "Motor Topper" (accelerometer based, 1 event atapogee, coin cell powered) for single deploy of streamer.

Consistently went about
4000ft in no wind conditions from 3950ft MSL launch site.

I made it so long because the G12 motor is so heavy, at the wrong end, and it's over optimum mass, so adding nose weight is not a good idea.

Compare with an F10 in an Apogee Aspire. That really will go over a mile. 29mm vs 32mm, better mass fraction, motor eject vs electronics..

All in fun!

 

[Titan II]

3 to 1 T/W = 2.33 pound rocket. Fly on a calm day and use a long rail. I have a 14' rail just for this type of rocket (without active stabilization).

 

[cls]

3 to 1 T/W = 2.33 pound rocket.

???? 12 newtons is 2.7 pounds, divide by 3, under 1 pound, so 14oz.

 

[Titan II]

???? 12 newtons is 2.7 pounds, divide by 3, under 1 pound, so 14oz.

32 newtons

 

[SolarYellow]

https://www.route66gunsandammo.com/

In Barstow might have some 4F from time to time. It's not too much farther than Lucerne.

 

[cls]

32 newtons

??? G12?

 

[Titan II]

??? G12?

Max thrust. I am not going to get into the average vs max debate.

 

[cls]

Max thrust. I am not going to get into the average vs max debate.

There's no debate.

Ok, reset.

Are you talking about G12ST DMS? https://aerotech-rocketry.com/products/product_726f702c-881b-dc52-9e27-a61fea955741

I'm talking about the G12 R/C T. https://aerotech-rocketry.com/products/product_939a0930-189f-03a0-d1fa-21dded87450e

Actually, doesn't matter what you were talking about, both have peak thrust around 20N. Not 32N.

 

[Titan II]

Actually, doesn't matter what you were talking about, both have peak thrust around 20N. Not 32N.

Actually it does. All three sources below, which includes the one you cited above, indicates 30.9.

https://aerotech-rocketry.com/products/product_726f702c-881b-dc52-9e27-a61fea955741

https://www.apogeerockets.com/Rocke...gle-Use/Aerotech-29mm-HP-SU-DMS-Motor-G12ST-P

https://www.thrustcurve.org/motors/AeroTech/G12ST/

 

[Art Upton]

Actually it does. All three sources below, which includes the one you cited above, indicates 30.9.

https://aerotech-rocketry.com/products/product_726f702c-881b-dc52-9e27-a61fea955741

https://www.apogeerockets.com/Rocke...gle-Use/Aerotech-29mm-HP-SU-DMS-Motor-G12ST-P

https://www.thrustcurve.org/motors/AeroTech/G12ST/

The Aerotech bolded link shows 20N, 4.5 Lb

 

[David Schwantz]

I like to use the commercial grade to measure.

https://www.uline.com/Product/Detai...ging&msclkid=bfdf8552380117430b1be353b9471af8

 

[Titan II]

The Aerotech bolded link shows 20N, 4.5 Lb

And this is further down the same page....

Peak Thrust: 30.9 N-sec​

I think one thing we can agree on is there are some discrepancies in published data. I found an old thread that may be relevant.

https://www.rocketryforum.com/threads/3-new-aerotech-motor-certifications-and-motor-files.147651/

 

[Art Upton]

And this is further down the same page....

Peak Thrust: 30.9 N-sec​

I think one thing we can agree on is there are some discrepancies in published data. I found an old thread that may be relevant.

https://www.rocketryforum.com/threads/3-new-aerotech-motor-certifications-and-motor-files.147651/

Thank you.

Interesting thread, but it still does not clarify the thrust error. [Edit: but does show a thrust curve where it hit over 7 lbs peak at the start ]

It did mention the error of the motor originally being to hot to certify. Perhaps when they made changes to the motor later for the heat, the peak reading changed?

Still with the low thrust of the main burn, if the rocket is too heavy it will leave the rail and at some point fall over under thrust.

 

[kramer714]

I built a katana jr, still need to paint it. I have never done D.D. I have everything I need except the Black powder, iv called every place around me that I can think of and checked online but can not find any 4f powder however bass pro did have 3f. I live in the southern California riverside county. Dose anyone know where I can find some?

Going to ROCstock? I can 'lend' you some.

Mike K

 

[WrRider]

Going to ROCstock? I can 'lend' you some.

Mike K

Thank you. I orderd some. I might make it Sunday I have a "Safty Saturday" class the 13th I was asked to help teach in, otherwise I would be there for sure. What's it like on Sunday?

I haven't painted the Katana jr yet so I haven't used rocksim. I want it %100 done before I use my free trial. I did not know open rocket was free so I might start some pre test. I also need to calculate my charges.

 

[kramer714]

Thank you. I orderd some. I might make it Sunday I have a "Safty Saturday" class the 13th I was asked to help teach in, otherwise I would be there for sure. What's it like on Sunday?

I haven't painted the Katana jr yet so I haven't used rocksim. I want it %100 done before I use my free trial. I did not know open rocket was free so I might start some pre test. I also need to calculate my charges.

Sundays are quieter than Saturdays up at ROCstock, depending on the crowd and the weather they launch to 12:00 or later. Come up after your class on Saturday, Night Rockets is pretty cool, plus there will be lots of folks camping out,

 

[WrRider]

Sundays are quieter than Saturdays up at ROCstock, depending on the crowd and the weather they launch to 12:00 or later. Come up after your class on Saturday, Night Rockets is pretty cool, plus there will be lots of folks camping out,

That doesn't sound like a bad idea. Could probably make it around 6pm.