"PSII" 2.5" Nike-X Design and Build Thread

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DigBaddy

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Yeah, there was no Estes PSII Nike-X but there should of been. I've decided to build one. It may not be a perfect replica, but going for close as reasonable. I'm not done designing, so some ideas and input are more than welcome before I start any kind of assembly.

The base of the build is 2.5" diameter PSII tubing and their 2.5" nose cone. The nose cone is not the correct profile, but there's a few reasons I chose this. A BT80-sized balsa nose cone with the correct profile was ~$35, and other BT-80 cones were too short. This cone is 10" long (not counting shoulder) and the scale-up would put a nose cone around 10.3" for this tubing (10.5" or so if using BT80). So this was really a nice way to go with it, IM
HO. The 2.5" tubing is a lot beefier than normal BT-80 so this should be more durable. With the above parts, I have 8" long 29mm motor tubes and threaded retainers on-hand, so that will be used. I plan to use 1/8" birch ply for the aft fin set, and 1/8" balsa for the front and mid set. All fins left square in my sims for now. I'm not an altitude junkie. Got a 24" nylon chute and various grades of kevlar and elastic cord to use for slowing it down before it hits the ground, so I should be set there. I'll be making my own centering rings like I did for my 3" Goblin project.

Now, the fun part I'm noodling on, and this is where any input is welcome, is how to handle the body coupling and separation at ejection. The length of BT from Estes came in 15.5" long pieces. I need about 34.3" of body tube. So, there's a 3.3" chunk of it in there somewhere. I have two 4" long couplers. One I've initially designed to be a baffle. In the attached OR file, I've got the short chunk of BT in the middle, BT-55 stuffer up to the rear coupler, then the front coupler would house a baffle.

With a baffle, I could pop the nose cone like normal or I could make this zipperless. I'm not too sure on zipperless. I don't know if I trust this lighter, lower inertia, stuff to actually ensure the laundry gets pulled out of the tube. But, it is a viable option from what I've read. Or, I could forget the baffle and run the stuffer up further and nomex blanket the recovery gear...and even that could be zipperless...right? I've also thought to cut two tubes down, and make it so a coupler is in front of the front centering ring, adding support/strength and really giving this the ability to fly harder hitting motors with less worry. Can still do stuffer/bafffle. Heck, I think I could even make a payload bay with this pile of parts and shrink the area for the ejection charge to fill that way. What would fellow TRF'ers do to make for reliable flights?

Thanks for any input, and as I build, I'll turn this into a build thread. Should be a fun one.

Current OR Screenshot
v2_or_screenshot.png

NC
IMG_20211024_142135566.jpg

Two 4" long couplers.
IMG_20211024_142157597.jpg

three 15.5" long body tubes
IMG_20211024_142213351.jpg
 

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TigerHawk

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Yeah, there was no Estes PSII Nike-X but there should of been. I've decided to build one. It may not be a perfect replica, but going for close as reasonable. I'm not done designing, so some ideas and input are more than welcome before I start any kind of assembly.

The base of the build is 2.5" diameter PSII tubing and their 2.5" nose cone. The nose cone is not the correct profile, but there's a few reasons I chose this. A BT80-sized balsa nose cone with the correct profile was ~$35, and other BT-80 cones were too short. This cone is 10" long (not counting shoulder) and the scale-up would put a nose cone around 10.3" for this tubing (10.5" or so if using BT80). So this was really a nice way to go with it, IM
HO. The 2.5" tubing is a lot beefier than normal BT-80 so this should be more durable. With the above parts, I have 8" long 29mm motor tubes and threaded retainers on-hand, so that will be used. I plan to use 1/8" birch ply for the aft fin set, and 1/8" balsa for the front and mid set. All fins left square in my sims for now. I'm not an altitude junkie. Got a 24" nylon chute and various grades of kevlar and elastic cord to use for slowing it down before it hits the ground, so I should be set there. I'll be making my own centering rings like I did for my 3" Goblin project.

Now, the fun part I'm noodling on, and this is where any input is welcome, is how to handle the body coupling and separation at ejection. The length of BT from Estes came in 15.5" long pieces. I need about 34.3" of body tube. So, there's a 3.3" chunk of it in there somewhere. I have two 4" long couplers. One I've initially designed to be a baffle. In the attached OR file, I've got the short chunk of BT in the middle, BT-55 stuffer up to the rear coupler, then the front coupler would house a baffle.

With a baffle, I could pop the nose cone like normal or I could make this zipperless. I'm not too sure on zipperless. I don't know if I trust this lighter, lower inertia, stuff to actually ensure the laundry gets pulled out of the tube. But, it is a viable option from what I've read. Or, I could forget the baffle and run the stuffer up further and nomex blanket the recovery gear...and even that could be zipperless...right? I've also thought to cut two tubes down, and make it so a coupler is in front of the front centering ring, adding support/strength and really giving this the ability to fly harder hitting motors with less worry. Can still do stuffer/bafffle. Heck, I think I could even make a payload bay with this pile of parts and shrink the area for the ejection charge to fill that way. What would fellow TRF'ers do to make for reliable flights.

Thanks for any input, and as I build, I'll turn this into a build thread. Should be a fun one.

Current OR Screenshot
View attachment 487122

NC
View attachment 487118

Two 4" long couplers.
View attachment 487120

three 15.5" long body tubes
View attachment 487121
[/QUOTE
Is it similar to the Loc Nike Zeus?
 

Scott_650

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Hmm..not a fan of baffles, a clogged one just seems to be a possible failure point.

But I’m loving the plan! A great what-if addition to the PSII line - if Estes had developed their own higher power motors this would’ve been a natural for them to do. Going to enjoy watching this develop.
 

Back_at_it

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If this were my build I think I'd connect the two long tubes with the first coupler and build the baffle into that. I would then use the 3.3 inch section as a payload bay at the very top. Have the rocket separate between the large tube and the 3.3 inch payload bay

On something in the 2.5 inch range I'd build the plate style baffle. Easy to build and easy to shake the junk out of it after flight.
 

DigBaddy

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If this were my build I think I'd connect the two long tubes with the first coupler and build the baffle into that. I would then use the 3.3 inch section as a payload bay at the very top. Have the rocket separate between the large tube and the 3.3 inch payload bay

On something in the 2.5 inch range I'd build the plate style baffle. Easy to build and easy to shake the junk out of it after flight.

This is a good suggestion, thanks! I can easily make the short section a bit longer and chop off some of a longer tube as well to make the payload bay a little bit larger. This then reduces the area to pressurize a bit more. I hate to end up with small chunks of multiple tubes, but odds of using more of this tubing are probably not the highest - who knows how long it'll be available. It is nice stuff though!
 

Back_at_it

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who knows how long it'll be available. It is nice stuff though!

When I found it was available again I went a bit overboard and bought a ton of tubes, cones and couplers so expect a whole lot of 2.0, 2.5 and 3.0 upscales in the future. Just kicking around some rockets I'd like to upscale and I've come up with 52 so far. I'm sure that number will grow :)

The sad part is I think I have everything to build all of them. Yeah I need a life!!
 

DigBaddy

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While contemplation on the tubing continues, I started on some things since it wouldn't affect anything else.

In an incredible stroke of luck, the excess corners from my Big Daddy 1/8" balsa sheets were the exact size needed for the mid set of fins. I had another small piece of 1/8" balsa from Super Baby Bertha that worked for the remaining one. The other corner of the Big Daddy sheets allowed easy cuts of the front fins/canards (whatever you want to call them). Love using scrap where I can, and this was perfect.

IMG_20211024_185933723.jpg

IMG_20211024_192054829.jpg

IMG_20211024_192706102.jpg

IMG_20211024_193910671.jpg
 

DigBaddy

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I get done working at a reasonable time on Fridays, so I did a little woodwork. Cut out the rear fins, made centering rings, a bulkhead for the payload bay (seems like the suggestion above is the best route), and then the front piece of the baffle that the recovery gear will attach to. That front piece of birch ply will be sandwiched between an upper/lower paper ring on the inside of the baffle coupler to help reduce the chance of it ripping out.

IMG_20211029_153555767.jpg

I also made cheap unwelded eye bolts into welded eye bolts.

IMG_20211029_153714663.jpg
 

DigBaddy

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Bottom 3 discs in the baffle. Will do the top end when I need to epoxy a few more things. Top will have a ring from some BT80 above and below it for extra reinforcement and probably a small stick of ply as a brace. Without the eyebolt I think it'll come in under 25g total.

Also updated the OR file posted above. Realized the fins got all messed up when I adjusted body tube section lengths.

IMG_20211102_083129174.jpg
 

DigBaddy

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Cut some fin slots and the fins fit in them. Motor tube sits perfectly against the tabs as well. Math is cool when you do it right.

IMG_20211103_135733637.jpg
 

DigBaddy

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Nice, the Nike-X is such a great design!

Oliver

Agreed! No progress on this lately, waiting to shoot primer after deer season and hopefully have the MDRM ready at the same time to be a bit more efficient.

I do have the decals from stickershock though! They look nice.
 

flaperon

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Very cool! I have my own BT-70 Nike X "variant" nearly complete. I'll get a pic up in few days when the paint is done.
 

DigBaddy

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Very cool! I have my own BT-70 Nike X "variant" nearly complete. I'll get a pic up in few days when the paint is done.
Yes! Want to see it!

I'm in the middle of sanding primer fun with this (and two other rockets). May get to shoot and wet sand another coat tomorrow.
 

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flaperon

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Yes! Want to see it!

I'm in the middle of sanding primer fun with this (and two other rockets). May get to shoot and wet sand another coat tomorrow.
Just decals to go....
 

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