An "R"-powered rocket build

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Onebadhawk
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one big advantage to metal tip is also providing an anchor point for it and the chute
I use one on my 3+ foot cone cause I can't reach down there to connect anything
 
Pat Gordzelik said:
BTW, the 38mm motor I mentioned above was a K. Point 62 second burn time.

Do the math

Pat G
Click to expand...

K3000? Sporty! :eek:

I really appreciate you coming by and talking a little bit about the motor design. It's really interesting even though I'm probably not headed toward research motors myself.
 
Theory said:
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!!!!!!
Click to expand...

Good question.

Let me look at smoothing that nose tip out with epoxy before painting.

Also I'm starting a more-critical 30" coupler assembly today. This one is important as the top centering ring along with the aluminum motor-retention plate has to be placed precisely.

I'll post a few pics of the whole process.

Thanks!

Chuck C.
 
Rail Dawg said:
Wow those tubes are incredible. Have to take out a mortgage to get them but that may just have to happen.

Nice! Thanks Dave.

Chuck C.
Click to expand...

Chuck,

I thought you might like those . . . Gotta get ready for the "T" motor, after the "S" motor !

BTW - A real Nike M-5 Booster ( 16.44" OD X 141.6" Long ) produces an average thrust of 43,973 lb. of thrust for 3.4 seconds . . . 195,679.85 Newtons of thrust for 3.4 seconds = 665,311.49 Nt-Sec ( 89.9 % "S" motor ) . . . A full "S" Motor is 655,360 Nt-Sec.

Dave F.

booster.gif

NIKE-M5-IGNITER.jpg

hurler-5.jpg
 
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Ez2cDave said:
Chuck,

I thought you might like those . . . Gotta get ready for the "T" motor, after the "S" motor !

BTW - A real Nike M-5 Booster ( 16.44" OD X 141.6" Long ) produces an average thrust of 43,973 lb. of thrust for 3.4 seconds . . . 195,679.85 Newtons of thrust for 3.4 seconds = 665,311.49 Nt-Sec ( 89.9 % "S" motor ) . . . A full "S" Motor is 655,360 Nt-Sec.
Click to expand...

Sorry for the "bad data" above . . . Corrected now !

BTW - A real Nike M-5 Booster ( 16.44" OD X 141.6" Long ) produces an average thrust of 43,973 lb. of thrust for 3.4 seconds . . . 195,679.85 Newtons of thrust for 3.4 seconds = 665,311.49 Nt-Sec (1.52 % "T" motor ) . . . A full "S" Motor is 655,360 Nt-Sec.

Dave F.

INTERNAL.JPG

hurler-5.jpg
 
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38B9D543-E54D-426C-81A0-3AF4193100AC.png


This is an example of a diagram the Engineering Dept sends me while I’m putting this rocket together.

Like they say a picture is worth a thousand words. This diagram allows me to study and plan exactly how this part of the rocket is going to go together.

The diagram is the 5’ section of rocket just above the motor casing. The 8” tube contains the drogue. It also serves as a stiffener for the coupler section between the lower motor airframe and upper airframe containing the avionics bay.

At even 10g’s during thrust there’s well over 1000 lbs of force on that critical joint. The joint is also subjected to wind shear as the rocket quickly moves through the various layers in the atmosphere. Because it has to separate during the drogue event the options are limited for strengthening.

My hat is off to Engineering for his help in the design of this big rocket.

Chuck C.
 
Rail Dawg said:
View attachment 382631


This is an example of a diagram the Engineering Dept sends me while I’m putting this rocket together.

Like they say a picture is worth a thousand words. This diagram allows me to study and plan exactly how this part of the rocket is going to go together.

The diagram is the 5’ section of rocket just above the motor casing. The 8” tube contains the drogue. It also serves as a stiffener for the coupler section between the lower motor airframe and upper airframe containing the avionics bay.

At even 10g’s during thrust there’s well over 1000 lbs of force on that critical joint. The joint is also subjected to wind shear as the rocket quickly moves through the various layers in the atmosphere. Because it has to separate during the drogue event the options are limited for strengthening.

My hat is off to Engineering for his help in the design of this big rocket.

Chuck C.
Click to expand...

Chuck,

Now, that is what I'm talking about . . . Great data !

On a cautionary note :

In addition to axial loads during boost and flexing/bending, due to Wind Shear, I strongly suggest looking at the "numbers", as the Angle of Attack varies at various velocities and air densities ( perhaps in a range of 0 - 20 Degrees ).

I also have concerns about possible "Coning" issues, not from fin misalignment, but from CG location, throughout the flight, as propellant is expended ( the farther forward the CG moves, relative to to the CP, the greater the tendency to "Cone" ) . . . Also, being a supersonic flight, the CP will also be shifting location, as velocity changes ! NOTE : CP also shifts with AoA ( Angle of Attack ).

https://www.narom.no/undervisningsr...1aerodynamics-and-forces-acting-on-the-rocket

https://www.grc.nasa.gov/WWW/K-12/rocket/cp.html

https://argoshpr.ch/joomla1/articles/pdf/sentinel39-galejs.pdf

https://web.archive.org/web/20090723192012/https://www.info-central.org/?article=124

WATCH THE FIN CAN AND LOWER AIRFRAME, THROUGHOUT THE FLIGHT . . .



Dave F.

40000 AGL -102 F.JPG



hurler-5.jpg
 
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Rail Dawg said:
View attachment 382631


This is an example of a diagram the Engineering Dept sends me while I’m putting this rocket together.

Like they say a picture is worth a thousand words. This diagram allows me to study and plan exactly how this part of the rocket is going to go together.

The diagram is the 5’ section of rocket just above the motor casing. The 8” tube contains the drogue. It also serves as a stiffener for the coupler section between the lower motor airframe and upper airframe containing the avionics bay.

At even 10g’s during thrust there’s well over 1000 lbs of force on that critical joint. The joint is also subjected to wind shear as the rocket quickly moves through the various layers in the atmosphere. Because it has to separate during the drogue event the options are limited for strengthening.

My hat is off to Engineering for his help in the design of this big rocket.

Chuck C.
Click to expand...

You (and/or Engineering) are probably on to this already, but you may want to glue in the lower centering ring so that the bottom is clean with no fillet. My thinking is that then you could set the top of the coupler so that it rests on the CR when the airframe meets up. It would take careful cutting and fabrication but would add a load path for the vertical loads.

If that booster coupler to drogue section airframe joint is already mechanically fastened, this may not be necessary or desirable.
 
jderimig said:
It's always wiser to consult the manufacturer than trf posts. There are no issues with Chuck's firmware.
Click to expand...

Without that TRF post, there would have been no indication of a potential problem . . .

Your post, in the TRF thread I linked to confirmed there was an issue ( "Contact me about your flight. There is a marsa firmware upgrade to improve your situation IF your unit is affected." )

I am not familiar with the units Chuck is using and alerted him to a possible problem, suggesting that he "check it out" and "verify" the situation. In other words, to contact the manufacturer, apparently, you !

Dave F.

hurler-5.jpg
 
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Ez2cDave said:
Without that TRF post, there would have been no indication of a potential problem . . .

View attachment 382697
Click to expand...

Fair enough. When there is potential problem customers on record with me get an email from me and if its a widespread issue I will post in the Vendor's section of this forum and the MarsaSystems website.

The problem mentioned in the post you reference only affects some TiltModules. All those customers, I know where all the TiltModules are have been notified and will be kept abreast of the status.

I just didn't want Chuck to panic.
 
jderimig said:
Fair enough. When there is potential problem customers on record with me get an email from me and if its a widespread issue I will post in the Vendor's section of this forum and the MarsaSystems website.

The problem mentioned in the post you reference only affects some TiltModules. All those customers, I know where all the TiltModules are have been notified and will be kept abreast of the status.

I just didn't want Chuck to panic.
Click to expand...

John,

Not a problem . . .

As I said, I'm not familiar with MARSA products and I wanted to give Chuck as much "lead time", as possible.

As an airline pilot, I don't think Chuck is the type to "panic" ( at least I hope not - LOL ! ) . . .

My advice was for him to check it out & verify, ASAP, and take action, if necessary !

Dave F.
 
boatgeek said:
You (and/or Engineering) are probably on to this already, but you may want to glue in the lower centering ring so that the bottom is clean with no fillet. My thinking is that then you could set the top of the coupler so that it rests on the CR when the airframe meets up. It would take careful cutting and fabrication but would add a load path for the vertical loads.

If that booster coupler to drogue section airframe joint is already mechanically fastened, this may not be necessary or desirable.
Click to expand...

Thanks boatgeek!

From Engineering:

The lower centering ring should not touch the motor. That's not a good load-bearing point. Besides being difficult to get the stackup correct, the vibration from the motor would transfer into the shear pin joints. The load of each section is handled by the airframe end faces fitting squarely against each other.

The compressive strength of G12 lengthwise is at least 30,000 psi. There's a few 100 psi on the airframe end face where the drogue and booster sections meet. The G12 will be more likely to buckle under compression plus a side load, therefore the airframe+coupler doubles the strength at the joint. And the internal structure of the inside tube, the CR's in each section, the slight telescoping, etc, help with flexing/bending resistance.

The main problem to avoid is the early shearing of the shear pins upon G-loads.... a tight and straight fit at the airframe face without other internal faces interfering (or vibrating) will prevent shear pins from deforming at lift off.

Chuck C.
 
Thanks for the info guys on the potential Marsa firmware issue.

It never hurts to be careful about so critical a system.

Mine are good and qualified for flight.

I do appreciate the help.

Chuck C.
 
Rail Dawg said:
Thanks for the info guys on the potential Marsa firmware issue.

It never hurts to be careful about so critical a system.

Mine are good and qualified for flight.

I do appreciate the help.

Chuck C.
Click to expand...

Chuck,

The "Steely-Eyed Missile Men" of the Support Team have your back, at all times !

I would rather sound a "false alarm", than permit a "deadly silence" to jeopardize the project, in any way.

Dave F.

hurler-5.jpg
 
Ez2cDave said:
Chuck,

The "Steely-Eyed Missile Men" of the Support Team have your back, at all times !

I would rather sound a "false alarm", than permit a "deadly silence" to jeopardize the project, in any way.

Dave F.

View attachment 382815
Click to expand...

Agreed Dave.

Sometimes it's that one voice that has the right answer.

It's always best to speak up. Never a dumb question or comment on this thread. We all have something to offer.

Chuck C.
 
Rail Dawg said:
Thanks boatgeek!

From Engineering:

The lower centering ring should not touch the motor. That's not a good load-bearing point. Besides being difficult to get the stackup correct, the vibration from the motor would transfer into the shear pin joints. The load of each section is handled by the airframe end faces fitting squarely against each other.

The compressive strength of G12 lengthwise is at least 30,000 psi. There's a few 100 psi on the airframe end face where the drogue and booster sections meet. The G12 will be more likely to buckle under compression plus a side load, therefore the airframe+coupler doubles the strength at the joint. And the internal structure of the inside tube, the CR's in each section, the slight telescoping, etc, help with flexing/bending resistance.

The main problem to avoid is the early shearing of the shear pins upon G-loads.... a tight and straight fit at the airframe face without other internal faces interfering (or vibrating) will prevent shear pins from deforming at lift off.

Chuck C.
Click to expand...

Sounds like Engineering has it all in hand. They’re right that sometimes adding a load path causes more problems than it solves. I didn’t realize that coupler tube was a direct link to the top of the motor.
 
boatgeek said:
Sounds like Engineering has it all in hand. They’re right that sometimes adding a load path causes more problems than it solves. I didn’t realize that coupler tube was a direct link to the top of the motor.
Click to expand...

Trust me this has been a good learning experience for me and all of us I bet.

What I'm enjoying is that this big rocket is coming together nicely and it's definitely being built to take the thrust. I have no doubt it's going to handle the R with ease.

I've got some build photos coming up tonight on a critical section of the rocket... where the top of the motor is centered and secured with aluminum plate. It's a complicated coupler-assembly. It's one of those measure three times cut once kind of deal as it has to be well-aligned.

Thanks boatgeek!

Chuck C.
 
So my first Q powered rocket was 16" sonotube, no fiberglass on it, and paper honeycomb fins with fiberglass face sheets. I was carefully to put the thrust loads in compression and added a bit of all-thread to take the fin drag loads. Not terribly expensive and it held up just fine [except for parachute issues]. The nosecone was a splurge [aircraft spinner off ebay], but could have been cut polystyrene foam just fine with a scrim layer of fiberglass to make it look nicer. I mention this because many seem to think that G10 is the only way to do a good design, but it is not. I have seen other folk's Q powered rockets that were carpentry works of art in wood and cardboard [and also flew just fine] without a ton of filament wound tube.

I don't see a Q rocket as any harder than what one 'should' be doing on one's L3 project, just bigger parts...

I am certainly not knocking the big fiberglass rockets, but they come with a significant dollar investment. People could be spending some of that on bigger motors [or more flights] with thoughtful material and engineering choices if they were so motivated.

br/

Tony
 
Rail Dawg said:
Trust me this has been a good learning experience for me and all of us I bet.

Chuck C.
Click to expand...

Chuck,

Yes, indeed . . . Many of the things we have done here, thus far, have caused me to re-think and re-design parts of my L3 Cert project ( by the end of the year or early next year ).

I hope to be able to serve in a similar capacity on future projects, too, sir !

Many Thanks !

Dave F.

hurler-5.jpg
 
OK here's the build I was working on today.

The first photo is the 30" coupler that will contain the top of the 9' 2-3/4" motor.

I put a birch 3/4" CR on the outside bottom. It has lines for knowing where to place the stringers.

The second photo shows the line at 9' 2-3/4" where the top of the motor will be in the rocket.

The third photo is the markings on where the top CR's will be in the 30" coupler. It's very important that I get within 1/2" of the upper mark when making the stringers and installing the (2) 3/4" CR's.

The fourth photo is the stringers in place with fillets and the first CR installed.

The fifth photo is the 30" coupler installed in the rocket. I needed the top CR in the coupler to be within 1/2" of 110-3/4". Success!

And finally the last photo is looking down the 9' stack of the rocket. The 30" coupler assembly just built will slide into the airframe and rest on the top CR you see in the stack.

Still need to fiberglass the stringers and then the 30" coupler assembly will be slid and epoxied into the rocket. I'm going to wait however for the motor casing to arrive before epoxying this in just to make sure it's a perfect fit.

Progress lol!!!

Chuck C.IMG_4976[1].JPG IMG_4977[1].JPG IMG_4979[1].JPG IMG_4981[1].JPG IMG_4983[1].JPG IMG_4975[1].JPG
 
Rail Dawg said:
OK here's the build I was working on today.

The first photo is the 30" coupler that will contain the top of the 9' 2-3/4" motor.

I put a birch 3/4" CR on the outside bottom. It has lines for knowing where to place the stringers.

The second photo shows the line at 9' 2-3/4" where the top of the motor will be in the rocket.

The third photo is the markings on where the top CR's will be in the 30" coupler. It's very important that I get within 1/2" of the upper mark when making the stringers and installing the (2) 3/4" CR's.

The fourth photo is the stringers in place with fillets and the first CR installed.

The fifth photo is the 30" coupler installed in the rocket. I needed the top CR in the coupler to be within 1/2" of 110-3/4". Success!

And finally the last photo is looking down the 9' stack of the rocket. The 30" coupler assembly just built will slide into the airframe and rest on the top CR you see in the stack.

Still need to fiberglass the stringers and then the 30" coupler assembly will be slid and epoxied into the rocket. I'm going to wait however for the motor casing to arrive before epoxying this in just to make sure it's a perfect fit.

Progress lol!!!

Chuck C.
Click to expand...

Chuck,

Thanks for the pics . . . That is exactly how I envisioned the construction to be, using the "stacked module" method !

That's a very wise precaution to verify the fit with the motor casing, before bonding the unit in place.

Dave F.

hurler-5.jpg
 
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