TRF Summer Build Off: SSC - Spiral Spin Can

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You know, when you get this kitted out, you're going to need to send one to me.

I'd love to give this a whirl.

LOL! You're a one-man show here Jim! :clap: I may kit the mini versions (I think they're a lot of fun and fly great!) and they would be more likely to survive the shipping to you; however to be honest, the shipping charge to you in China is the big issue (costs more than several kits the last I checked and with the risk of shipping damage, it's a risky affair)...maybe a bunch of us TRF'ers can get together to figure out a good way to ship you a rocketry care package. :)

This is really looking nice Ken. Excellent work sir!!!

Thanks Kevin! :)
 
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I never did use the "spinning" bouncing bomb attachment on the AVRO Lancaster. That attachment did not get the Dan seal of approval and later mindsims foretold it would just get burned up anyway, so I have never spun anything off a rocket or tried to use spin stabilization. The bearing spinny thing looks cool. It will add weight to the bottom which will require a bigger motor, which will require more nose weight, which in turn will require an even bigger motor. The spinniness will cause a lot of drag and will need big, quick, punchy power to get going fast off the rod. Power and nose weight rule! Spinning saucers and fin cans are cool. rstaff3 Sea Monsters are cool:wink:.


Ok... I've been re-reading this thread, and just saw this post...

No bouncing bombs? Dam!
 
Ok... I've been re-reading this thread, and just saw this post...

No bouncing bombs? Dam!

Gettin' spiny attachment things on yer rockets past the RSO table will always be a challenge! I could work if I just moved it back a tad. That would mean building a Lancaster "MkII" with additional bomb bay chute ejection. Goin' up is easier than comin' down. Don't want to get the chute tangled up in the spiny parts.
 
Ok... I've been re-reading this thread, and just saw this post...

No bouncing bombs? Dam!

I missed that too! I actually already knew what that was...used to be a WWII military buff. :)

[video=youtube;bOGRTlrYCIE]https://www.youtube.com/watch?v=bOGRTlrYCIE[/video]

Daddyisabar - you should try for the bomb anyway...maybe not make it spin and instead have a light ball drop off (like the Meteor Masher or the Cluster Bomb). :fly:

meteor_masher.gif
 
Not you too, noooooooo, why Ken why?

Haha! No worries...I was mostly kidding. Notice the pokemon theme in the pics I included? I couldn't resist!

I've gotten quite a lot done on the 29mm & 38mm last week and will make a video of the slick system once I get a chance to make the 38mm fin can. Right now the problem is I'd like more than I have time to build...I still want 29mm spiral and straight fin cans as well as 38mm spin, spiral and straight cans as well as a 29mm DD bay (may have to de-prioritize that last one). I'll try to have the 29mm and 38mm ready for my club's August launch and if I miss any launches there, there's another club launching a week or so later. I'll update once I get a chance to get the first 38mm fins on and a video done.

As a side note I just found out my sister (who is over 50) just admitted that she's hooked on Pokemon Go! She said it's the first "video game" she's played since Pac Man came out in the arcades. This is quite a phenomena...(try to ignore the stupid things people are doing...the same happened when cars, computers, gps and texting first came out). :)
 
Haha! No worries...I was mostly kidding. Notice the pokemon theme in the pics I included? I couldn't resist!

I've gotten quite a lot done on the 29mm & 38mm last week and will make a video of the slick system once I get a chance to make the 38mm fin can. Right now the problem is I'd like more than I have time to build...I still want 29mm spiral and straight fin cans as well as 38mm spin, spiral and straight cans as well as a 29mm DD bay (may have to de-prioritize that last one). I'll try to have the 29mm and 38mm ready for my club's August launch and if I miss any launches there, there's another club launching a week or so later. I'll update once I get a chance to get the first 38mm fins on and a video done.

As a side note I just found out my sister (who is over 50) just admitted that she's hooked on Pokemon Go! She said it's the first "video game" she's played since Pac Man came out in the arcades. This is quite a phenomena...(try to ignore the stupid things people are doing...the same happened when cars, computers, gps and texting first came out). :)

Lol, no I didnt notice the pokemon puns lol. I knew you were joking. I just dont see you playing that pointless game.


Alexander Solis - TRA Level 1 - Mariah 54 - CTI-I100 Red Lightning Longburn - 6,345 Feet
 
Right now the problem is I'd like more than I have time to build...I still want 29mm spiral and straight fin cans as well as 38mm spin, spiral and straight cans as well as a 29mm DD bay (may have to de-prioritize that last one).
I've lost track: are the 29 and 38 mm the motor sizes or tube sizes? Remember that, strictly for contest purposes 29 mm is the limit for the engine. That should help with prioritizing.
 
I've lost track: are the 29 and 38 mm the motor sizes or tube sizes? Remember that, strictly for contest purposes 29 mm is the limit for the engine. That should help with prioritizing.

No problemo! :grin:

Well, I started on the upscale fins...after hours of trying to figure out the 29mm design (MD or 38mm bt?), I figured I'll use 29mm blue tube first and was aiming for 38mm cardboard outer.
 
Time for some updates - most of which was done earlier the past week...

On the 29mm MD build I JB Welded the LL (launch lug) to the collar...afterwards, I realized that I didn't think enough about where the LL was going and just put it opposite the locking screw for balance. This resulted in the locking screw no longer lining up with one of the screws holding in the ejection baffle. :facepalm:
Oh well, the locking screw into the heavy wall blue tube should be fine...I'll have to ponder if I should bother grinding off the LL or putting another in place just to get the locking screw in the right place...probably not

I also added another layer to the collar as well as an outer nut JB welded into place...seems plenty strong and the LL is now raised in line with the one at the bottom. Additionally, I epoxied a plywood CR to the female screw on adapter.

2016-07-14%2022.47.46.jpg


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I was now mostly done with the 29mm MD version...I had one spin can, but would like to also/eventually:
  • Have a spiral and straight fin can as well
  • Make a 29mm DD bay
  • Install an Eggfinder in the nose (seems to fit, but will need to make a proper mount)
  • Enter this into Rocksim

2016-07-23%2020.11.41.jpg
 
So at about the same time I couldn't resist starting on the 38mm build (my work is all about multi-tasking and has put me on the road of trying to do too much as once).

It took me a lot of thinking to decide on the size of the 38mm sections, but in the end came up with something I was happy with. I wanted the lower spin section longer so that the upper bearing would be more weight forward/forward of the CG, but also needed enough of the upper section covering the 29mm bt so that it would be stronger and straigher. I ended up with both sections being 18".

Here's a shot of the lower 29-38mm CRs glued in place...I used double at the bottom since I felt there might be more force from the entire section pushing down on the lower bearing as the rocket boosts.
2016-07-17%2010.26.44.jpg


I didn't take pics of some of the other stuff, but I glued on the upper CR in to the spin can and sanded the ID of both until they were loose enough and then put in the needle bearings and the lower can spun very nicely (had to do a bit of sanding of the upper CR since it apparently was a bit crooked).

I then glued in the upper female pvc fitting and did a test fitting and it worked great! Here is the system as it is now...the next step is to make 38mm spin fins and glue it to the spin can.

29mm MD (again):

2016-07-23%2020.11.41.jpg


29mm MD taken down and 38mm outer parts (also male pvc fitting in place):

2016-07-23%2020.14.11.jpg


38mm "bearinged" rocket with 29mm motor mount (currently "finless", but no worries...it will eventually have fins :)):

2016-07-23%2020.15.52.jpg


Modular is FUN! :grin:
 
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2016-07-23%2020.11.41.jpg



[FONT=&amp]Modular is FUN! [/FONT]:grin:

[FONT=&amp]So... This is how you unwind?

Sorry about the dupe post... apparently TRF is stuck in rewind. (I did try to delete the dupe... Honestly)[/FONT]
 
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Haha! Don't get me wound up Jim! :wink:

Just a quick update that my bandsaw's blade snapped (not a pleasant experience!), so I'll need to get a new blade before I cut out any more fins...or maybe I'll do it the old way with a hack/coping saw...ugh. Hopefully I can get some fin sets done by the club launch next week.
 
Time for another update!

Well, I took a look at my bandsaw hoping to replace the broken blade with the spare I had on hand, but no luck...when the blade broke, it also broke the rubber grip ring around the upper pulley, so it was out of commission for a while. Given that and my limited time (club launch is this weekend!), I decided to make a set of straight fins rather than trying for a second more "spirally set". Additionally, while I really, really wanted to try the 38mm conversion, I was just too far behind on that, work for me has been really crazy, and I had to finish up the 29mm version for the upcoming launch, so that was put on the backburner for now.

So I grabbed my trusty X-acto hand saw (or similar) and hacked up a set of straight fins. I figured it's best to first fly the scratch build in a conventional set up before going with the spiral can so it would be less concerning to the RSO.

2016-08-04%2022.12.42.jpg


I then mounted the fins on a collar with wood glue and painted it white with flo red fins. I thought I took a pic, but I guess I forgot; however you can see it in post #262 below.
 
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Well, this weekend was a tough one for me. Work was crazy during the week and Saturday was busy too with personal and family matters and I only managed two naps Saturday night (11AM-1 AM and then 6AM-7AM) in trying to finish up the 29mm build in time for the Sunday launch (which I figured would be the last for me before this contest ends).

The main part I needed to finish was the nose cone. I had a 29mm CF nose cone from a Mongoose 29mm CF rocket I had (I know...not the best use of a CF nose cone, but it was the only one I had and I figured I'd be able to adapt it back to the Mongoose).

I wanted to fit an Eggfinder into the nose since I figured it was an MD and it could get serious altitude and be hard to sight coming down (boy was I right...more on that later). It was a daunting challenge to try to fit everything in and also make some sort of anchoring point for the harness...

2016-08-07%2003.43.02.jpg


I considered using 8-32 allthread, but felt it may take up too much space, so I tried a threaded coupler JB Welded into the nose.

2016-08-07%2004.23.02.jpg


It seemed good and I tightened down the cover. Note I had to angle the eyelet so that the link would clear the side.

2016-08-07%2004.34.33.jpg


I then tried to test fit it into the rocket. Very tight fit! Apparently the cover needed to be sanded down for a good fit. So I pulled the nose cone off and the coupler ripped right out! Maybe I didn't wait long enough for the JB Weld to harden, but at 3AM it was back to the drawing board. :facepalm:

2016-08-07%2004.49.45.jpg


So I went back to the original plan of using allthread. I cut a section slightly longer than the nose and bent the end so that it would conform to the nose shape, then I epoxied it in. Then I attached an allthread coupler and eyelet.

2016-08-07%2005.02.36.jpg


Given the time and my difficulty finding a suitable battery to fit in the nose cone (along with it's charger), I gave up on fitting the Eggfinder in the nose for now. KISS! So no G motors in this one for now.
 
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So it was time to finish things up. I had a thin mil 30" chute I wanted to use, which I thought would be good for this since it was on the heavy side with the blue tube, basswood fins, internal baffle and retainer. The only problem was it was proving to be a very tight fit. The baffle limited space inside the rocket and the allthread coupler and eyelet were also taking up some space. I was concerned about how tight things were, but didn't have much choice at that point since the next smaller thin mill chute I had (19") had thick chute lines (what's with that?). Oh well, I figured I'll try my best to repack stuff at the field.

I did some rocksims on a similar MD design which I altered to match my build and came up with F44-8W being a good choice among the motors I had. On this mootr, it would be just over 1,000', keeping it within sight...hopefully. It was also good that this motor, an Economax, was 24mm, which would keep rear weight down making it more stable. Only issue was that I would need to use a 29mm-24mm motor adapter, which I had never used with a Slimline retainer before...how hard can that be? More on that later. After I get the Eggfinder in, I'll try a G motor.

Time for a last minute one-hour power nap before heading out to the launch! :)
 
Okay, time for launch this morning! I packed my vehicle, headed out and then...headed back since I left the rocket(s) on my front deck. :facepalm: That's what sleep dep does to you. :blush: I got to the club and started to prep the rocket...I repacked the chute best I could and also fit in an JL Alt Two. The fit was tighter than I'd like, but not much choice at this point and I figured crossing my fingers would help. ;) I then masking taped the 24mm motor into the adapter and inserted it into the Slimline retainer. However when I tried to fit the ring (which they say must be used), it wouldn't fit over all that masking tape! Arrrgh! I had to remove some tape until I could slip on the ring and then the clip retainer.

Okay, FWD and we're on the pads with the straight fin version as a first launch! :grin:

2016-08-07%2010.19.29.jpg
 
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5-4-3-2-1...ZOOM!

[video=youtube;MStTe91t6to]https://www.youtube.com/watch?v=MStTe91t6to&feature=youtu.be[/video]

Straight fin rocket went up...which is good! However then it came down...fast. Arrgh.

I lost sight of it since ejection happened right about where the sun was. I went out to the field heading towards the sun, meanwhile doing the dreaded "how much did I just lose" tally in my head. However a fellow rocketeer in the field with me finally spotted it in the next field on my left..

2016-08-07%2010.37.59.jpg
 
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What club is that, and where is it?

METRA - Great group of guys out there and LOTS of experience. Always a great time to be had! :clap:

Thanks for leaving some in suspense Neil! :wink:

BTW - I originally thought of attending the next RR launch, but will be away that weekend, so that's why I figured this Sunday was my last chance before the contest end; however that doesn't mean the project end for me.
 
'bout time you posted some updates... we've been twisting in the breeze waiting.
 
Well, as I pulled out the rocket, I was hoping for the best...

...and guess what?

I got it! :grin:

2016-08-07%2010.38.36.jpg


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NO DAMAGE! :eyepop: That blue tube stuff was great!

Upon further inspection, it turns out that the motor blew out from the masking tape and this caused the failed ejection. I thought for sure I would have to update my sig with another lost/destroyed rocket, but Woo Hoo!
 
BTW - Usually fins in the middle of the rocket after a lawn dart when they started at the bottom of the rocket at launch isn't such a good thing. :tongue: I think the design I had allowed the collar retainer's sliding down to absorb some of the impact forces from destroying the front of the tubing.
 
So I then reassembled the rocket and inspected it to be good for another launch!

As a baseline, the JL Alt Two recorded 317kph & 336m.

I then switched the bottom to a spin can and proceeded to load another F44-8W motor. This time I added a bit more masking tape; however it still ended up being too much to be able to fit in the Slimline retainer ring system. Arrrgh. :facepalm: I asked around the club, but no one I asked had experience with it. I then figured I'd CHAD retain it...I added more tape on the outside in a hash pattern around the nozzle and taped around the base of the retainer for good measure. As an extra measure, I decided to use the 19" chute since a smaller chute would still bring it down slower than a big chute stuck inside the rocket! Additionally, there seemed to be some thermals over the fields today due to the heavy sun. The smaller chute fit much better!

So I proudly brought back the rocket to the pads and called it "Lawn Dart Part II" for good measure...can't lose that way! :wink: (Note the CHAD retaining tape on the bottom.)

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[video=youtube;1VKZLTIof_E]https://www.youtube.com/watch?v=1VKZLTIof_E&feature=youtu.be[/video]

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SUCCESS! :horse:

Rocket went up beautifully and seemed straighter to me. The straight fin went out a bit towards the fields on launch, but this one went directly overhead.

The Alt Two read 3011kph* (blinking) & 357m

*Side note is that the Alt Two had hit the dirt on the lawndarting...I had to clean some out of the button area. Not sure if this screwed up the speed read, but figured I'd mention it. I think it may be 301.1kph.
 
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