An "R"-powered rocket build

Put 4 additional vertical stringers into the lowest coupler assembly. Got it all glassed in.

Very solid build! I like it. No pic but when I get back home I’ll do that.

Chuck C.

Rail Dawg said:

Put 4 additional vertical stringers into the lowest coupler assembly. Got it all glassed in.

Very solid build! I like it. No pic but when I get back home I’ll do that.

Chuck C.

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Chuck,

Looking forward to seeing the pics . . .


Dave F.

Making good progress on the coupler assemblies.

Get the centering ring installed, put in 8 vertical stringers, add some nice fillets then glassing them in. Install the other centering ring and check for fit.

Am doing a "motor fit" test as I go although the real test will come once the coupler assemblies are dry-fitted into the airframes. Then we can see if everything lines up correctly. Any mistakes are easily fixed with just a bit of sanding although right now it's looking good.

Also included is a pic of the rocket barn as it starts to look more and more like a... well... rocket barn!

Chuck C.

I like your rocket mascots

great stuff!

..and is that a mix of "kitty hair" on your mixing board? I used that a lot building custom speaker enclosures "back in the day." some extremely strong stuff.

Rail Dawg said:

Making good progress on the coupler assemblies.

Get the centering ring installed, put in 8 vertical stringers, add some nice fillets then glassing them in. Install the other centering ring and check for fit.

Am doing a "motor fit" test as I go although the real test will come once the coupler assemblies are dry-fitted into the airframes. Then we can see if everything lines up correctly. Any mistakes are easily fixed with just a bit of sanding although right now it's looking good.

Also included is a pic of the rocket barn as it starts to look more and more like a... well... rocket barn!

Chuck C.

Click to expand...

Chuck,

Looking good and coming along nicely . . . Your "guard dogs" look like they are "on the job" !

Dave F.

Theory said:

..and is that a mix of "kitty hair" on your mixing board?

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Yes, the dogs keep him "well supplied" . . . LOL !

Dave F.

Theory said:

great stuff!

..and is that a mix of "kitty hair" on your mixing board? I used that a lot building custom speaker enclosures "back in the day." some extremely strong stuff.

Click to expand...

Yep that's glass fiber lol. Using it for the fillets.

Chuck C.

Ez2cDave said:

Chuck,

Looking good and coming along nicely . . . Your "guard dogs" look like they are "on the job" !

Dave F.



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Have to watch them though. They like to take supplies out into the yard.

Chuck C.

Here's pic showing the lengths of the coupler assemblies and airframe. I'm working my way from the bottom of the rocket upwards.

Once the coupler assemblies are completed and dry-fitted in I'll start work on the 24" avionics bay. The avionics bay has to carry the load from the main parachute all the way down to the upper enclosure of the motor where there is a 3/4" forged-steel eyebolt.

The avionics bay will have a total of (4) 1/2" forged-steel eyenuts connected by (2) 1/2" B7 grade threaded rods. This provides 7500 lbs of force for an empty weight rocket of about 375 lbs.

is a single chute bringing all of this down?

also curious as it is difficult to tell where your drogue sits and where it is getting deployed from

Theory said:

is a single chute bringing all of this down?

also curious as it is difficult to tell where your drogue sits and where it is getting deployed from

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Recovery is still the 800lb Gorilla in the room . . . There is much to do in this area.

Dave F.

Theory said:

is a single chute bringing all of this down?

also curious as it is difficult to tell where your drogue sits and where it is getting deployed from

Click to expand...

Still thinking about the parachute(s). Part of me wants to use 2 Rocketman 36' chutes in deployment bags. I've had nothing but success with their chutes. I really like having only 4 shroud lines.

The pic I posted above was just to show the coupler assemblies and airframe lengths.

Below is the full Open Rocket diagram.

Chuck C.

Oh man you're killing me.

Rodger. And you have time to ponder recovery as you assemble the coupler assemblies

This is 100% not my area of expertise, so I will avoid commenting as the last thing I want to provide is poor advice

Rail Dawg said:

Still thinking about the parachute(s). Part of me wants to use 2 Rocketman 36' chutes in deployment bags. I've had nothing but success with their chutes. I really like having only 4 shroud lines.

Chuck C.

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Chuck,

What is the total volume available for recovery devices ?

How much space do those Rocketman chutes take up, when folded ?

What type of recovery harness is planned ?

Drogue size & type ?

Dave F.

I’m no expert on recovery of this size either. The biggest rocket I have ever built was 7.5” x 72”. I would contact rocket man and see what they suggest. Also contact onebadhawk about a harness.

I did the recovery on a 1/3 scale V2 that weighed 180#, 28 foot man rated chute takes a lot of space

Below is Ky Michaelson (Rocketman) after packing a 16' chute.

You can see it packs quite well. I did speak with Rocketman and (2) 36' chutes would work well with the about 400# of rocket. We've got about 3 1/2ft of 12" tube to work with. Easy to extend this space if needed.

To answer Dave a 6-8 ft Rocketman drogue. (2) Rocketman braided Kevlar shock cords rated at 2520lbs ea for the main parachute(s). All hardware will exceed 5000lbs strength.

Rocketman will make a 60' parachute as a custom-order. Expensive but so is the rocket.

As the build progresses toward the avionics bay and recovery systems more time can be devoted to those systems. Right now the goal is building a very heavy-duty structure. We aren't interested in altitude-busting but in showing off some very powerful motors.

Chuck C.

Talking with Buddy Michaelson at Rocketman right now. He's taken over for his dad Ky who is a legend in our rocketry world!

He recommends a 50 ft Pro-X parachute. These guys know their stuff and will help ensure we have a bomb-proof setup.

Chuck C.

Rail Dawg said:

Below is Ky Michaelson (Rocketman) after packing a 16' chute.

You can see it packs quite well. I did speak with Rocketman and (2) 36' chutes would work well with the about 400# of rocket. We've got about 3 1/2ft of 12" tube to work with. Easy to extend this space if needed.

To answer Dave a 6-8 ft Rocketman drogue. (2) Rocketman braided Kevlar shock cords rated at 2520lbs ea for the main parachute(s). All hardware will exceed 5000lbs strength.

Rocketman will make a 60' parachute as a custom-order. Expensive but so is the rocket.

As the build progresses toward the avionics bay and recovery systems more time can be devoted to those systems. Right now the goal is building a very heavy-duty structure. We aren't interested in altitude-busting but in showing off some very powerful motors.

Chuck C.

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Chuck,

Are you still considering the option of bringing the rocket down in two pieces ?

If not, I favor the single chute setup over dual chutes, mainly from the standpoint that multiple chutes might foul or tangle.

Speaking of "very powerful motors", are we close to the first static test ? Some "real world" numbers would be most welcome !

Dave F.

That being said we get to choose the colors for the parachute.

What's ya'lls opinion? I like red and white?

Chuck C.

Rail Dawg said:

That being said we get to choose the colors for the parachute.

What's ya'lls opinion? I like red and white?

Chuck C.

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Chuck,

Yes, indeed . . . Red & White is a fine choice !

Dave F.

Rail Dawg said:

Below is Ky Michaelson (Rocketman) after packing a 16' chute.

You can see it packs quite well. I did speak with Rocketman and (2) 36' chutes would work well with the about 400# of rocket. We've got about 3 1/2ft of 12" tube to work with. Easy to extend this space if needed.

To answer Dave a 6-8 ft Rocketman drogue. (2) Rocketman braided Kevlar shock cords rated at 2520lbs ea for the main parachute(s). All hardware will exceed 5000lbs strength.

Rocketman will make a 60' parachute as a custom-order. Expensive but so is the rocket.

As the build progresses toward the avionics bay and recovery systems more time can be devoted to those systems. Right now the goal is building a very heavy-duty structure. We aren't interested in altitude-busting but in showing off some very powerful motors.

Chuck C.

View attachment 378788

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that is a 16 foot chute with 200 sq feet
28 foot chute is 600 sq ft
36 is 1000 sq ft
50 is 2000 sq ft

you may want to get the chutes to see what space they take
just saying

jbr said:

that is a 16 foot chute with 200 sq feet
28 foot chute is 600 sq ft
36 is 1000 sq ft
50 is 2000 sq ft

you may want to get the chutes to see what space they take
just saying

Click to expand...

Good point. Not too concerned. Once you see the size of the airframe you'll realize there's plenty of room for a very large chute.

Appreciate the input!

Chuck C.

This modular design using G-12 is really working out well. I'm very pleased with the structure.

Here's two of the completed coupler assemblies next to the airframe that will be slid over them. Many of us who build the big rockets make an internal frame using ribs and stringers and then slide the outer skin over it.

This is similar to that except the couplers are modular. It's a very tough design although heavier.

I've sanded the couplers and internal part of the airframe and the fit is beautiful.

The markings on the lowest coupler is for the placement of the bolts for the aluminum fin can. Behind the lines are those wide stringers I put in the wrong way but it turns out it was a beneficial mistake. Go figure! Usually my mistakes cost me hours of time lol. Having the wide stringer there makes it easy to bolt the fin can through with washers and nuts on the inside.

Also shown is a stringer with globs of Pro-Set epoxy on it. You place that into the coupler using lines drawn onto the bottom CR so they are evenly spaced. The extra epoxy pushes out to the side then the ol' popsicle stick is used to create the fillet.

Coming along!

Chuck C.

Rail Dawg said:

Behind the lines are those wide stringers I put in the wrong way but it turns out it was a beneficial mistake. Go figure! Usually my mistakes cost me hours of time lol. Having the wide stringer there makes it easy to bolt the fin can through with washers and nuts on the inside.

Chuck C.

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Chuck,

Perhaps, it wasn't a 'mistake", at all, but, merely, a "subconscious re-design" ?
( Think anyone will "buy" that theory ? - LOL ! )

The rocket is really coming along nicely, with great progress being made . . . Looking forward to seeing the entire process unfold !

Dave F.

Got the 12" diameter nose cone in. It's hand-laid fiberglass done by Curtis Turners' wife.

Really a nice job.

Starting to make some real progress on how the recovery system will work. Once the details are hammered out I'll post on here so you all can see what we're thinking. Going to the bigger rockets the recovery system doesn't "scale-up" at all. With a 400 lb empty weight rocket at possibly 15-20 G's every part of the system has to handle 8000 lbs of force.

As we all know it's the weakest link that will doom our rockets.

Again I'll post soon what we're coming up with.

Thanks.

Chuck C.

Rail Dawg said:

Got the 12" diameter nose cone in. It's hand-laid fiberglass done by Curtis Turners' wife.

Really a nice job.

Starting to make some real progress on how the recovery system will work. Once the details are hammered out I'll post on here so you all can see what we're thinking. Going to the bigger rockets the recovery system doesn't "scale-up" at all. With a 400 lb empty weight rocket at possibly 15-20 G's every part of the system has to handle 4000 lbs of force.

As we all know it's the weakest link that will doom our rockets.

Again I'll post soon what we're coming up with.

Thanks.

Chuck C.

View attachment 378973

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Chuck , your rocket is coming along very nice . Was the nose cone made extra thick , or reinforced in any way that you know of ? I would be concerned enough to look into the Aero load / heat on the cone . I've seen and had my share of clamshell cones from him collapse under boost around mach 2. I am not nocking his work at all .

3stoogesrocketry said:

I would be concerned enough to look into the Aero load / heat on the cone . I've seen and had my share of clamshell cones from him collapse under boost around mach 2.

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Maybe a couple extra layers laid on the inside and some foam?