An "R"-powered rocket build

0011001100 said:

Don't worry no rush. Was just curious as I've gotten into making my own (much) smaller motors and am always open to learning.

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As am I! I can build a rocket no problem but the motors are a whole other can of worms. Am lucky to have two of the best amateur motor masters in the business.

Chuck C.

Here's the launch trailer "before" picture before it heads up tomorrow to our Launch Pad engineer and fellow TRF'er Levi Seaton in Madison, KS.

Levi is going to modify the trailer so we have a hydraulic lift tower and manual outriggers. A Predator super-quiet 5500w generator and tool boxes will also be on the launch trailer.

In the trailer are 2 10' radio antenna sections along with the 20' Unistrut 1000T launch rail.

I'll tell you what getting a big rocket ready to launch ain't easy! And I couldn't do it without the help of all of you and a lot of other smart people behind the scenes.

Chuck C.

Rail Dawg said:

Here's the launch trailer "before" picture before it heads up tomorrow to our Launch Pad engineer and fellow TRF'er Levi Seaton in Madison, KS.

Levi is going to modify the trailer so we have a hydraulic lift tower and manual outriggers. A Predator super-quiet 5500w generator and tool boxes will also be on the launch trailer.

In the trailer are 2 10' radio antenna sections along with the 20' Unistrut 1000T launch rail.

I'll tell you what getting a big rocket ready to launch ain't easy! And I couldn't do it without the help of all of you and a lot of other smart people behind the scenes.

Chuck C.

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Chuck,

Ahh . . . The "War Wagon" - LOL !

Some points to consider :

(1) Can Levi fabricate some "pants" to protect your tires, so you don't have to remove and reinstall them ?

(2) Can Levi fabricate some "Leveling Jack Screws" that can be lowered to stabilize the trailer, once it is at the launch site and disconnected from the tow vehicle ?

( Attaching inverted "Scissor Jacks" to the underside of the frame of the trailer might be a good option . . . Wooden blocks would be placed on the ground and the jacks lowered down on to them )

(3) That wooden "deck" surface might need some sort of fire-proofing or replacement with "diamond plate" or "diamond mesh" ( I like the "mesh" option ).

Just some "thoughts" . . .

Dave F.

Ez2cDave said:

Chuck,

Ahh . . . The "War Wagon" - LOL !

Some points to consider :

(1) Can Levi fabricate some "pants" to protect your tires, so you don't have to remove and reinstall them ?

(2) Can Levi fabricate some "Leveling Jack Screws" that can be lowered to stabilize the trailer, once it is at the launch site and disconnected from the tow vehicle ?

( Attaching inverted "Scissor Jacks" to the underside of the frame of the trailer might be a good option . . . Wooden blocks would be placed on the ground and the jacks lowered down on to them )

(3) That wooden "deck" surface might need some sort of fire-proofing or replacement with "diamond plate" or "diamond mesh" ( I like the "mesh" option ).

Just some "thoughts" . . .

Dave F.

View attachment 381694

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Not bad ideas Dave.

Thanks!

Chuck C.

Got the launch trailer up to Levi Seaton in Kansas today. Levi is an outstanding welder and is highly motivated to make this platform look professional.

After Kansas dropped down into Texas near Abilene to pour some more Q grains. Again this first motor will be a test motor.

I appreciate everyone’s great inputs over the past 6 months. Many of your ideas have been incorporated into the build of this rocket. It’s turning out to be as strong as a telephone pole lol.

Thanks!

Chuck C.

Rail Dawg said:

Got the launch trailer up to Levi Seaton in Kansas today. Levi is an outstanding welder and is highly motivated to make this platform look professional.

After Kansas dropped down into Texas near Abilene to pour some more Q grains. Again this first motor will be a test motor.

I appreciate everyone’s great inputs over the past 6 months. Many of your ideas have been incorporated into the build of this rocket. It’s turning out to be as strong as a telephone pole lol.

Thanks!

Chuck C.

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Chuck,

The "Steely-Eyed Missile Men" have your back . . . Now, about this "telephone pole" thing :

www.dailymotion.com/embed/video/x4olu6h



Dave F.

Finally finishing up the Q motor. We vacuum degas the propellant and the density is right where we want it.

The contraption you see surrounding the propellant grain is what it takes to hold down the casting sleeve while the propellant is being poured. Without it the hydraulic pressure of 30 lbs of propellant lifts the casting sleeve off the base.

The mandrel is HDPE coated in silicone mold release and Dow 111. The 111 isn’t cheap but it does allow the mandrel to slide off the grain easily. Later on we’ll roughen up the core to remove the 111 and provide a good surface for ignition.

It takes 3 people to do a pour plus having 3 sets of eyes keeps mistakes to a minimum. The pace while mixing is relaxed but when the curative is added things get busy real quick. We’ve got about 20 minutes after the curative is added to mix, complete the degas process and pour before the propellant starts to set enough where it doesn’t pour easily.

The grains you see are about 20” long. Each one is a 40% O motor lol!

Chuck C.

I am intrigued by what seems like a giant core relative to the OD of the grain. Is that to keep the motor from becoming erosive? To an untrained eye, it looks like a lot of wasted space, though I'm sure there's a good reason.

[mods, please step in if we are straying too deep into motor design for a general thread]

boatgeek said:

I am intrigued by what seems like a giant core relative to the OD of the grain. Is that to keep the motor from becoming erosive? To an untrained eye, it looks like a lot of wasted space, though I'm sure there's a good reason.

[mods, please step in if we are straying too deep into motor design for a general thread]

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Its because this is a Q motor in the same case as a R motor. Larger core = less propellant = smaller motor. The later motors I assume will have smaller cores for more propellant loading.

0011001100 said:

Its because this is a Q motor in the same case as a R motor. Larger core = less propellant = smaller motor. The later motors I assume will have smaller cores for more propellant loading.

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Of course, that makes all the sense in the world. Thanks!

boatgeek said:

I am intrigued by what seems like a giant core relative to the OD of the grain. Is that to keep the motor from becoming erosive? To an untrained eye, it looks like a lot of wasted space, though I'm sure there's a good reason.

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They're going to put an M motor inside of it

djs said:

They're going to put an M motor inside of it

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*As the igniter

As the saying goes "How do you light a Q? With an I!"

grain geometry all depends on nozzle throat size and max internal pressure you desire
also lift off thrust should be high to get it going

What jbr is saying is the answer.

It’s called Kn. The core seems excessive but it’s exactly what is needed to produce the calculated thrust.

Good stuff guys!

Chuck C.

Rail Dawg said:

The grains you see are about 20” long. Each one is a 40% O motor lol!

Chuck C.

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Chuck,

Looking forward to seeing static test results . . .

Is that the world's first "Soda-Can" O-motor ?

LOL !

Dave F.

What's the volume loading? What's BS report for peak MF?

Rail Dawg said:

What jbr is saying is the answer.

It’s called Kn. The core seems excessive but it’s exactly what is needed to produce the calculated thrust.

Good stuff guys!

Chuck C.

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Apologies if you answered this already. Is the R just a couple more grains than the Q with the same grain geometry? If so, do you have a separate Q case or some spacers in the R case?

Looking back, "just" should maybe be in air quotes there, since a single grain of this beastie is likely more motor than I will ever fly.

Rail Dawg said:

What jbr is saying is the answer.

It’s called Kn. The core seems excessive but it’s exactly what is needed to produce the calculated thrust.

Good stuff guys!

Chuck C.

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To All,

I am no motor expert, but I have been reading up on motor-making, recently.

"Kn" is the ratio of the surface area of burning propellant to the cross-sectional area of the nozzle throat.

"Kn" is the factor that controls the "chamber pressure" of the motor during operation . . . Too low = hard to light, chuffing, & less efficient operation . . . Too high = "B-O-O-M" ( CATO )

"Kn" is not linear . . . Doubling Kn does not double chamber pressure, it triples chamber pressure !

I now defer to the "real" experts . . .

Dave F.

Dave says.
"Kn" is the ratio of the surface area of burning propellant to the cross-sectional area of the nozzle throat.

"Kn" is the factor that controls the "chamber pressure" of the motor during operation . . . Too low = hard to light, chuffing, & less efficient operation . . . Too high = "B-O-O-M" ( CATO )

"Kn" is not linear . . . Doubling Kn does not double chamber pressure, it triples chamber pressure !"

Dave, Pat G here. For a newbie on motors of the solid persuasion, you're a pretty quick study! Well done!

Actually, in reply to some who have queried about the core size versus web, the core is basically centered around the nozzle throat size. There is a rule of thumb using a multiplier on throat openings in comparison to core to prevent erosive burning, but I have been informed that specifics on motor building here have limited parameters. So I will speak generally. There is also a rule of thumb on the relationship to web size comparative to propellant length, but that is also a topic for another venue.

There are many, many things that effect solid oxidizer (and there are several, including AP and AN, etc) motor performance (or failure). Propellant (solid) density, burn rates, solids loading, mass flux, etc are all little witches that can bite you in the britches. I have made a lot of motors, (at last count, over 20000 lbs worth), but I have had my share of britch bite too, and it seems everybody remembers the failures . I must admit, a few of those failures were because I took things for granted, and got lax. I call those "education opportunities". Scar tissue helps you remember to absorb the lesson.

The Q planned for LDRS is basically 92" of propellant that weighs approx 137.1 lbs. 8.2 seconds burn time, peak thrust of approx 2 tons. And all accomplished with under 400 PSI of motor operating pressure. I am looking forward to the event.

Chuck has gone to a tremendous amount of effort (and expense) on this project, and has gone thru a few gauntlet lines in the process, but the man is a brute, and he continues unfazed, in no small part thanks to his virtual team, you folks. I intend to assist him in the propulsion part to the best of my abilities.

Chuck, the last grain is curing nicely, I intend to pull the core tomorrow evening when I get back to my ranch from a solar installation job. Had a hoot the last few days, thanks for all the help, and hope you made it back home safely.

Hasta manana.

Pat G

Pat Gordzelik said:

Dave says.
"Kn" is the ratio of the surface area of burning propellant to the cross-sectional area of the nozzle throat.

"Kn" is the factor that controls the "chamber pressure" of the motor during operation . . . Too low = hard to light, chuffing, & less efficient operation . . . Too high = "B-O-O-M" ( CATO )

"Kn" is not linear . . . Doubling Kn does not double chamber pressure, it triples chamber pressure !"

Dave, Pat G here. For a newbie on motors of the solid persuasion, you're a pretty quick study! Well done!

Actually, in reply to some who have queried about the core size versus web, the core is basically centered around the nozzle throat size. There is a rule of thumb using a multiplier on throat openings in comparison to core to prevent erosive burning, but I have been informed that specifics on motor building here have limited parameters. So I will speak generally. There is also a rule of thumb on the relationship to web size comparative to propellant length, but that is also a topic for another venue.

The Q planned for LDRS is basically 92" of propellant that weighs approx 137.1 lbs. 8.2 seconds burn time, peak thrust of approx 2 tons. And all accomplished with under 400 PSI of motor operating pressure. I am looking forward to the event.

Chuck has gone to a tremendous amount of effort (and expense) on this project, and has gone thru a few gauntlet lines in the process, but the man is a brute, and he continues unfazed, in no small part thanks to his virtual team, you folks. I intend to assist him in the propulsion part to the best of my abilities.

Pat G

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Hi, Pat !

Thank you for the kind words . . . I am flattered !

From my reading, erosive burning becomes a concern on motors that have a length to diameter ratio of 8:1 or greater, right ?

I'm looking forward to seeking static test data, so we can get an accurate performance prediction for the UpChuckR.

The "Steely-Eyed Missile Men" have Chuck's back, each within their own areas of expertise. I consider it an honor to work alongside other rocketeers, even as only a small part of this incredible project !

Pat, your reputation precedes you and I have the utmost confidence in all aspects of motor design, construction, and performance, with you handling things !

Dave F.

"From my reading, erosive burning becomes a concern on motors that have a length to diameter ratio of 8:1 or greater, right ?"

O gosh no Dave. Way to conservative. I have run 38mm motors with an ID of 1.238" and aggregate grain length of 26". That is 21 to 1 for the astute mathematicians on the list. The grain ID on this motor is 7". We are well below, using the above example, the 147" max length.

That said, I usually limit myself to 18 to one max as a safety factor.

BTW, the 38mm motor I mentioned above was a K. Point 62 second burn time.

Do the math

Pat G

So glad Pat G has stepped up to the forum as the Motor Master for both the Q and R motors being built.

Let me tell you it's one thing to know the formulations and how to mix all the chemicals but there's something far deeper about making motors. It's that knowledge gained from decades of practice and thousands of pounds of motors. Pat G has an intrinsic grasp of solid rocket fuel and I really do consider him the best in the country.

Yeah I'm blowing some smoke up his skirt but the man deserves the praise. He's one of the most generous people I have ever met of both his time and knowledge.

Jim Ballard also was there for 5 full days of mixing and his help was critical especially during "the pour" where time is of the essence. Jim is a good man with a big heart and I'm honored to have him as a friend.

Oh and Pat and Jim this one is for you:



Chuck C.

Rail Dawg said:

So glad Pat G has stepped up to the forum as the Motor Master for both the Q and R motors being built.

Let me tell you it's one thing to know the formulations and how to mix all the chemicals but there's something far deeper about making motors. It's that knowledge gained from decades of practice and thousands of pounds of motors. Pat G has an intrinsic grasp of solid rocket fuel and I really do consider him the best in the country.

Yeah I'm blowing some smoke up his skirt but the man deserves the praise. He's one of the most generous people I have ever met of both his time and knowledge.

Jim Ballard also was there for 5 full days of mixing and his help was critical especially during "the pour" where time is of the essence. Jim is a good man with a big heart and I'm honored to have him as a friend.

Oh and Pat and Jim this one is for you:

View attachment 382324

Chuck C.

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O look Jim.

Chuck sent a picture of himself as a child....

chortle.....

Folks, I'm telling ya, it was a hoot. But then, if you can't find time enjoying your passion, it really ain't worth spending that time, is it?

Ad Astra..

A Q today, an R tomorrow, an S to the future

Pat G

Pat Gordzelik said:

O look Jim.

Chuck sent a picture of himself as a child....

chortle.....

Folks, I'm telling ya, it was a hoot. But then, if you can't find time enjoying your passion, it really ain't worth spending that time, is it?

Ad Astra..

A Q today, an R tomorrow, an S to the future

Pat G

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Building the S is also going to be a fun project Pat.

Chuck C.

That's hilarious Chuck.....Thanks for that! (inside joke)

Looks just like him when he throws a tantrum.....

On another note guys the Engineering Dept for this rocket has signed off on not using a metal tip for the nosecone.

The few seconds above mach just isn't enough to cause any damage to the tip. We'll reinforce the inside of the tip with good epoxy and then put in a few layers of strong fiberglass on the inside.

It's going to be a well-built nosecone quite capable of handling the flight even on the R motor.

Chuck C.

For the S-powered rocket it's going to depend on how well the Q and R-powered rocket and motors fly. There's some consideration to building another 12" diameter rocket with a 10" diameter motor casing or stepping the rocket up to a 16" diameter. This would be another G-12 fiberglass design.

Thanks to many of you (and the Engineering Dept) we have created a very solid design using the "coupler assembly" approach to building a rocket that has the strength of a telephone pole.

I'm very pleased so far with the current build. As Pat G mentioned many of you have contributed in a very positive way to the design of the rocket now under construction. There are a myriad of decisions that have to be made with each one affecting the integrity of the build.

Seeing it all come together is exciting. For those going to LDRS and/or BALLS I encourage you to please stop by and introduce yourself. Something like this doesn't happen in a vacuum and the inputs are appreciated!

Chuck C.

Cool deal Chuck, and good to hear that the sims prove that metal tip isn’t needed.

That said, I remember from many posts ago that the “factory tip” might be less than desirable, is this going to be addressed?

Also, any more pictures of the airframe / coupler assemblies??? Looking forward to seeing the vehicle assembled!!!!!!