An "R"-powered rocket build

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Lol hope you have a few thousand welding rods for that one. Those fin fillets are going to be a real bugger.
 
Rail Dawg said:
You're right about the tail end and I'm going to see if the centering rings and carbon or fiberglass coating on the airframe will be stiff enough to get the job done.

Chuck C.
Click to expand...
For the payload section, I suspect the 24" tube within a 30" tube will act a lot like fiberglass sandwich construction...and may not need much reinforcement....
 
Just got word from KloudBusters that this is too large (and potentially dangerous!) of a project for LDRS 2019.

I have to agree as they made some very good points.

Kind of figured this would end up being a Black Rock project... I spend a great deal of time gold mining in the Northern Nevada desert and have quite a love for the area.

Have to talk with Pat G. a little bit later on about all this... I'd love to shove this motor into a minimum diameter 12" airframe lol.

Anyway I'll pause on the build for just a bit but that doesn't mean it's not going to happen!

I do appreciate KloudBusters playing it safe as they do have a responsibility for a large group of flyers.

Chuck C.
 
Please don’t pause for too long! I’m living vicariously through this thread.
 
Don’t worry there is going to be a rocket built! And soon!

Pat G. has been busy all this week and I’ve left him alone. Would like to hear his opinions on this recent development.

Again building-wise a 12” G-12 rocket with bulletproof fins and several wraps of airframe carbon would be much easier.

A real screamer on an “R” lol.

Chuck C.
 
Rail Dawg said:
You're right about the tail end and I'm going to see if the centering rings and carbon or fiberglass coating on the airframe will be stiff enough to get the job done.

Chuck C.
Click to expand...
My guess is your flight loads are less than your landing load on one fin. You are not planning on going that fast flutter should be easy to mitigate through fin shape and matl. choice. Even bonding to the two centering rings and not having a center body tube is a joint that is going to be stronger than the fin itself.
 
OK here's more of a minimum diameter 12" 15 ft tall rocket.

Even with 300 lbs of motor in the tail the CP/CG looks pretty good.

Lots of parts missing this is just a first crack.

Am thinking of getting some custom aluminum fins if we go this route and bolt them into the G-12 airframe/centering rings.

Far easier to build and get launched although too much altitude for LDRS 2019... probably a Black Rock bird.

Chuck C.


Screenshot (6).png
 
Running some ideas past KloudBusters since their waiver is 50,000 ft.

Am thinking if I build a 12” rocket beefy enough it can be kept under the waiver.

Did you guys see those thrust numbers Pat G posted a couple pages back? Is there any way to get those motor numbers into Open Rocket?

I’m not up to speed on that process but would like to start some flight simulations.

Any help with this appreciated.

Chuck C.
 
maybe this is a sign to throttle back, give everything a third, forth and fifth review, and aim for a different (later) launch. no reason to add weight / re-design a rocket to keep it under a waiver when there are outer launches that will fit a more ideal concept.

never hurts to be too carful, especially with that beast of a motor you are working with.
 
Theory said:
maybe this is a sign to throttle back, give everything a third, forth and fifth review, and aim for a different (later) launch. no reason to add weight / re-design a rocket to keep it under a waiver when there are outer launches that will fit a more ideal concept.

never hurts to be too carful, especially with that beast of a motor you are working with.
Click to expand...

I think you're right.

Building a 12" rocket that will scream on an "R" would be a blast... pun intended lol.

This looks like a Black Rock project. Going to have to really look at things to decide the best course.

Thanks.

Chuck C.
 
Rail Dawg said:
OK here's more of a minimum diameter 12" 15 ft tall rocket.

Even with 300 lbs of motor in the tail the CP/CG looks pretty good.

Lots of parts missing this is just a first crack.

Am thinking of getting some custom aluminum fins if we go this route and bolt them into the G-12 airframe/centering rings.

Far easier to build and get launched although too much altitude for LDRS 2019... probably a Black Rock bird.

Chuck C.
Click to expand...

Chuck,

Based on the velocity that this project is likely to reach, coupled with the weight being recovered, I suggest looking at the fin planform very carefully. Supersonic flight is guaranteed and descent rate during recovery is also problematic, given the mass involved.

My "armchair suggestion" is a fin with a forward-swept trailing edge, coupled with a long root edge and strongly swept-back leading edge.

Here is an "extreme" project . . . https://ddeville.com/derek/Qu8k.html

Something like this type of fin, perhaps ? ( Below - disregard dimensions )

Dave F.


findims2.jpg
 
Ez2cDave said:
Chuck,

Based on the velocity that this project is likely to reach, coupled with the weight being recovered, I suggest looking at the fin planform very carefully. Supersonic flight is guaranteed and descent rate during recovery is also problematic, given the mass involved.

My "armchair suggestion" is a fin with a forward-swept trailing edge, coupled with a long root edge and strongly swept-back leading edge.

Here is an "extreme" project . . . https://ddeville.com/derek/Qu8k.html

Something like this type of fin, perhaps ? ( Below - disregard dimensions )

Dave F.


View attachment 369262
Click to expand...
Most of my " sport rockets" use something similar to design 3 & 4....they handle supersonic flight very well and don't get damaged landing...I have to admit, if I had that motor I'd be tempted to shrink the tube 3" extend it another foot and build a full scale " Tomahawk".... especially if it's going to have to go to Black Rock anyhow....
 
Ez2cDave said:
Chuck,

Based on the velocity that this project is likely to reach, coupled with the weight being recovered, I suggest looking at the fin planform very carefully. Supersonic flight is guaranteed and descent rate during recovery is also problematic, given the mass involved.

My "armchair suggestion" is a fin with a forward-swept trailing edge, coupled with a long root edge and strongly swept-back leading edge.

Here is an "extreme" project . . . https://ddeville.com/derek/Qu8k.html

Something like this type of fin, perhaps ? ( Below - disregard dimensions )

Dave F.


View attachment 369262
Click to expand...


EXACTLY the help I need Dave!

Really like that design.

Thanks!

Chuck C.
 
Ez2cDave said:
Supersonic flight is guaranteed and descent rate during recovery is also problematic, given the mass involved.
Click to expand...

Recovery is a big question...

We all want our rockets to go straight up but if this things gets a mind of it's own and heads less-than-vertical we're talking a high-speed drogue deployment.

With this 12" diameter couplers come back into play easy enough.

It would be a "zipperless" design brought to us years ago by Stu Barrett.

Here's the motor upper enclosure with a box cutter for scale.

IMG_4765[1].JPG

It's beefy.

Would like to tie the entire recovery into this anchor unless there are reasons I'm missing not to do so.

Maybe a 500 lb rocket depending how beefy it's built. Loaded motor is 300 lbs.

Chuck C.
 
I like the Qu8k design you posted Dave.

No reason not to follow a successful rocket design.

I'm already starting to reach out to some machinists about possibly building a 12" 6061 aluminum fin can with 4 super-sonic fins welded to it.

The 12" G-12 fiberglass tube would fit into it.

Inside the G-12 tube would be all G-12 couplers essentially doubling the airframe strength.

Just throwing ideas out.

Chuck C.
 
Rail Dawg said:
Recovery is a big question...

We all want our rockets to go straight up but if this things gets a mind of it's own and heads less-than-vertical we're talking a high-speed drogue deployment.

With this 12" diameter couplers come back into play easy enough.

It would be a "zipperless" design brought to us years ago by Stu Barrett.

Here's the motor upper enclosure with a box cutter for scale.

View attachment 369272

It's beefy.

Would like to tie the entire recovery into this anchor unless there are reasons I'm missing not to do so.

Maybe a 500 lb rocket depending how beefy it's built. Loaded motor is 300 lbs.

Chuck C.
Click to expand...
What size eyebolt ? Here's a useful link.... https://www.amesweb.info/Fasteners/ForgedEyeBolts/Forged_Eye_Bolt_Capacity.aspx
 
Paulb06 said:
What size eyebolt ? Here's a useful link.... https://www.amesweb.info/Fasteners/ForgedEyeBolts/Forged_Eye_Bolt_Capacity.aspx
Click to expand...
The eyebolt should have a size embossed on it....the size is the diameter of the bolt...things to remember are, if it's screwed into an aluminum closure ...the length of the threaded part of the eyebolt needs to be 2x the diameter to hit the rated capacity...critical load rating isn't the working load for our purposes...that's for overhead lifting...the numbers to look at are the proof load...and the breaking strength..if you exceed the proof load, you need to replace the bolt...
 
Blowing the left one up to a 24" root only gives you ~9in height.

You need about a 28.8in root to keep those same angles but get up to ~12in height, which assumes 4 fins.
 
dhbarr said:
Blowing the left one up to a 24" root only gives you ~9in height.

You need about a 28.8in root to keep those same angles but get up to ~12in height, which assumes 4 fins.
Click to expand...

Binder Design says he thinks he can build a 12" 6061 aluminum fin can but the root length would be limited to 24".

Based on that can you give the measurements or something close to the Max Q design? I just plug those into the "free form" fin size on Open Rocket I assume.

I can play with the length of the rocket to keep the CP and CG where they need to be.

Chuck C.
 
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