An "R"-powered rocket build

TonyL said:

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

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Good points Tony.

I’m finding that at these levels it doesn’t scale up easily.

Even at just 10g’s there is 6000 lbs of weight on the lower end of the rocket.

No matter what there’s a 300 lb motor that has to be planned for.

The recovery system can be subjected to significant g’s.

While expensive the G-12 is a good choice for handling the predicted stresses.

Other materials as you said will work just fine as long as the forces are planned for accordingly.

Thanks for the input!

Chuck C.

Chuck , I am sure you have seen this already and talk to Curtis about it . I would consider the change.

3stoogesrocketry said:

Chuck , I am sure you have seen this already and talk to Curtis about it . I would consider the change.

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Yes that’s a great idea. Curtis’ work is exceptional.

Not sure the lead time but will pursue it.

Thanks for the heads-up!!

Chuck C.

Question about the Stratologger CF battery.

PerfectFlite recommends putting 2 of their LiPo batteries in series to run the Stratologger.

Is there a single LiPo battery that you can recommend? Lots of choices out there and I’d like to use the best one to run this altimeter. Prefer just 1 battery rather than 2 in series.

Thanks!

Chuck C.

Hi Chuck,
my point is that a single unsupported 2x4 will take that 6000 lbs [and more] over a reasonable distance just fine. A large diameter thin walled tube by itself is almost the hardest way to transmit axial thrust loads through a vehicle's structure.

Your design is fine as is, not suggesting you should have done anything differently, just pointing out that relying on the body tube strength is not the only way to design structure to transmit loads.

Furthermore, if the 'body tube' is not necessary to transmit thrust and drag loads, then its strength requirement is mostly to support itself, opening up more choices for body material. There are several examples of different alternate structural approaches in some of the really large physical scale projects over the years, some better than others.

Personally I am a fan of a central thrust carrying member sized such that buckling limits are of no concern, and yes it all scales up or down to any size motor ['strength of materials' engineering is nice that way].

That said, large really nice fiberglass or carbon fiber rockets can be works of art, so it all depends on what one's objectives are. I am looking forward to seeing you fling yours into the sky

br/

Tony

TonyL said:

Hi Chuck,
my point is that a single unsupported 2x4 will take that 6000 lbs [and more] over a reasonable distance just fine. A large diameter thin walled tube by itself is almost the hardest way to transmit axial thrust loads through a vehicle's structure.

Your design is fine as is, not suggesting you should have done anything differently, just pointing out that relying on the body tube strength is not the only way to design structure to transmit loads.

Furthermore, if the 'body tube' is not necessary to transmit thrust and drag loads, then its strength requirement is mostly to support itself, opening up more choices for body material. There are several examples of different alternate structural approaches in some of the really large physical scale projects over the years, some better than others.

Personally I am a fan of a central thrust carrying member sized such that buckling limits are of no concern, and yes it all scales up or down to any size motor ['strength of materials' engineering is nice that way].

That said, large really nice fiberglass or carbon fiber rockets can be works of art, so it all depends on what one's objectives are. I am looking forward to seeing you fling yours into the sky

br/

Tony

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Thanks Tony! We’re on the same page and you’re exactly right.

One reason for the G-12 is I’m lazy and didn’t want to fiberglass/CF this large a rocket lol.

You’ve built some great rockets and your design ability is proven.

Thanks again!

Chuck C.

Ok just got word a high-quality 9v alkaline battery will work just fine for the altimeters.

Glad to hear it as I like the basics.

The batteries will be locked in tight and oriented so the thrust pushes down on the connections.

Thanks!

Chuck C.

Rail Dawg said:

Question about the Stratologger CF battery.

PerfectFlite recommends putting 2 of their LiPo batteries in series to run the Stratologger.

Is there a single LiPo battery that you can recommend? Lots of choices out there and I’d like to use the best one to run this altimeter. Prefer just 1 battery rather than 2 in series.

Thanks!

Chuck C.

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It sounds like I am a bit late but this is what I use Turnigy Nanotech 2S 180mAh and they are the same Lipo's that PerfectFlite uses to test their units in-house.
Several sources available. HobbyKing would be my first choice but out of stock.
https://www.ebay.com/i/253867559006?chn=ps
https://hobbyking.com/en_us/turnigy-nano-tech-180mah-2s-25-40c-lipo-pack-5pcs.html

Rail Dawg said:

The batteries will be locked in tight and oriented so the thrust pushes down on the connections.

Chuck C.

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Chuck,

Acceleration G forces are not your only concern . . . Deceleration G forces and vibration ( from aerodynamic buffeting, Drogue deployment, and "motor harmonics" ) also should be considered and addressed, as I see it "from my chair" !

Dave F.

Ez2cDave said:

Chuck,

Acceleration G forces are not your only concern . . . Deceleration G forces and vibration ( from aerodynamic buffeting, Drogue deployment, and "motor harmonics" ) also should be considered and addressed, as I see it "from my chair" !

Dave F.

View attachment 383025

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Very good points Dave.

Chuck C.

No pics right now but got the aluminum bulkplates for the AvBay plus motor retention.

The 1/8” motor retention plate sits right on the CR that matches the top of the motor. Below that CR are 8 3/4” birch plywood stringers as part of the coupler assembly. It’s a solid base for retention.

The retention plate has a 3/4” hole where the forged-steel eyebolt inserts before being threaded into the motor’s stout upper enclosure.

It’s a very robust system as the 3/4” eyebolt is the anchor for the entire recovery system.

There will also be a recovery backup anchor which I’ll lay out later.

Heading into remote northern Nevada to try and find some gold with my brother. About 30 miles from Black Rock. Been going for years but still haven’t found the Mother Lode. Just enough to keep it exciting. Need to hit the big stuff to afford this very expensive hobby lol.

Appreciate the help with this rocket will be out of touch until maybe Monday.

Chuck C.

Rail Dawg said:

Heading into remote northern Nevada to try and find some gold with my brother. About 30 miles from Black Rock. Been going for years but still haven’t found the Mother Lode. Just enough to keep it exciting. Need to hit the big stuff to afford this very expensive hobby lol.

Chuck C.

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Chuck,

Watch out for rattlesnakes and "bandits" . . . Please be sure to post your GPS coordinates, whenever you find any gold, too . . . Thanks !

LOL !

Dave F.

Ez2cDave said:

Chuck,

Acceleration G forces are not your only concern . . . Deceleration G forces and vibration ( from aerodynamic buffeting, Drogue deployment, and "motor harmonics" ) also should be considered and addressed, as I see it "from my chair" !

Dave F.

View attachment 383025

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For that reason I use battery clips on leads rather than battery clips that are part of a holder. Even if the battery comes loose (should never happen right?) the clip on its lead stays attached to the battery and the altimeter.

"For that reason I use battery clips on leads rather than battery clips that are part of a holder. Even if the battery comes loose (should never happen right?) the clip on its lead stays attached to the battery and the altimeter."

Yep, do that too -- only on one flight the 9V battery came loose from the mount yet stayed wired with the taped-down clip...and became a ball-and-chain like object bashing the crap out of the altimeter it was wired to.
Murphy is a bitch.....

FredA said:

became a ball-and-chain like object bashing the crap out of the altimeter it was wired to.

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That's pretty funny in hindsight. How was it secured, and what acceleration did it experience?

(also I'm really curious why you forego the reply-to/quote feature and copy/bold. Seems labor intensive)

FredA said:

"For that reason I use battery clips on leads rather than battery clips that are part of a holder. Even if the battery comes loose (should never happen right?) the clip on its lead stays attached to the battery and the altimeter."

Yep, do that too -- only on one flight the 9V battery came loose from the mount yet stayed wired with the taped-down clip...and became a ball-and-chain like object bashing the crap out of the altimeter it was wired to.
Murphy is a bitch.....

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Which is why I always put the battery on the other side of the sled. But you’re right, Murphy’s ruthless.

FredA said:

"For that reason I use battery clips on leads rather than battery clips that are part of a holder. Even if the battery comes loose (should never happen right?) the clip on its lead stays attached to the battery and the altimeter."

Yep, do that too -- only on one flight the 9V battery came loose from the mount yet stayed wired with the taped-down clip...and became a ball-and-chain like object bashing the crap out of the altimeter it was wired to.
Murphy is a bitch.....

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Hungry too.......

Nytrunner said:

How was it secured, and what acceleration did it experience?

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My interpretation:

"How was it secured ?" . . . Not well enough !

"What acceleration did it experience ?" . . . Too much !

LOL . . . Sorry, I'm kind of bored tonight.

Dave F.

FredA said:

...and became a ball-and-chain like object bashing the crap out of the altimeter it was wired to.

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I believe you are describing a "MACE" . . .

Dave F.

Yes, a mace-like thrashing.
The motor cato'ed....was a wild ride.
The battery was epoxied in - was meant to be single use, but not the altimeter.

And once it breaks loose, it flies around all over bashing stuff in it's way....no matter where it's located.
Remember, it's tethered to the one thing in the EBAY you don't want it to hit so imagine what it hits....

That particular kind of mace is called a "morning star." -- D&D John

I got rid of a ball and chain from my last marriage..

tada dump

Chuck,

You might want to pass these links along to the "Motor Guru's" . . .

https://aerospaceamerica.aiaa.org/year-in-review/improving-efficiency-and-fuel-ignition/

https://www.purdue.edu/newsroom/rel...ellant-for-missile,-space-launch-systems.html

https://www.purdue.edu/newsroom/rel...o-showcase-technology-for-pentagon-brass.html

https://engineering.purdue.edu/discovery/2017_1/boilermaker-blastoff

Dave F.

Mighty quiet around here . . . Too quiet !

Dave F.

I’m baaack!

Just got home ready to continue building.

Need to finish up the 30” coupler that holds the top of the motor casing. All that’s left is fiberglassing the stringers.

AvBay is about 75% done. Mainly just need to get the electronics installed including the on/off switches.

Along those lines if anyone has a new PerfectFlite StratoLogger CF altimeter that they’d like to sell please let me know. I’m on the waiting list but would like to get it placed into the AvBay sled soon.

Ordered a most-awesome Rocketman 50’ parachute. Red and white. Decided to go with just 4 shroud lines. Plus we’ll have the Rocketman team on site to assist with the parachute packing (using a Rocketman deployment bag) at both LDRS and BALLS.

It’s coming together!

Chuck C.

Rail Dawg said:

Along those lines if anyone has a new PerfectFlite StratoLogger CZ altimeter that they’d like to sell please let me know. I’m on the waiting list but would like to get it placed into the AvBay sled soon.

Chuck C.

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Chuck,

"CZ" ? Did you mean "CF" ?

Dave F.

Chuck,

You have a PM !

Dave F.

Ez2cDave said:

Chuck,

"CZ" ? Did you mean "CF" ?

Dave F.

View attachment 383733

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I did mean CF.

Thanks Dave.

Chuck C.

Rail Dawg said:

I did mean CF.

Thanks Dave.

Chuck C.

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Chuck,

Those units are mighty scarce . . . I thought you were going with MARSA units ?

Dave F.

1 Marsa and 1 Stratologger now.

Chuck C.