First HPR Build - Wildman Punisher 3

[boatgeek]

That's funny, because I am actually leaning the other way...

I am trying to figure out ways to use smaller than the "average" fillet radii most folks use.

I am using the Delrin because it doesn't need lubricant and they are available in sooooo many more diameters. I can tailor the radius of a filleted bond to exactly the minimum required radius.

This SHOULD result in a significant reduction in overall adhesive volume used.... and thus less "dead" weight.

I believe that the aerodynamically optimum fillet radius is around 4% of root chord length.

I have had that PRECISE conversation!!


Yep.... she is linear like me, likes most all the things I like, and is very.... VERY smart.
But we speak completely different "engineering languages".

Mine was not a conversation. It was a statement. Fools rush in where angels fear to tread.

 

[cautery]

I believe that the aerodynamically optimum fillet radius is around 4% of root chord length.

Yes, I have seen that percentage bandied about, and is where I started.... Wonder what the qualifications to this "rule of thumb" are? Does it take into consideration the increase in frontal aspect ratio? Or any of the many other related variables that interact to produce thrust eating drag and weight?

I really should have finished my engineering education....

Mine was not a conversation. It was a statement. Fools rush in where angels fear to tread.

ROTFLMAO!! My wife just asked me what was so funny.... still laughing. Yep.... funniest thing I've read today, because it's true!

 

[boatgeek]

Yes, I have seen that percentage bandied about, and is where I started.... Wonder what the qualifications to this "rule of thumb" are? Does it take into consideration the increase in frontal aspect ratio? Or any of the many other related variables that interact to produce thrust eating drag and weight?

I really should have finished my engineering education....

Check out the linked thread. There are some references in there. The person who gave the figure said it was a balance of frontal area and hard corners generating vortices. They also said that this is an area very, very deep into the optimization. Fin shape, fin profile, nose cone shape, weight, etc. will all have much bigger effects on the rocket's altitude.

 

[cautery]

Check out the linked thread. There are some references in there. The person who gave the figure said it was a balance of frontal area and hard corners generating vortices. They also said that this is an area very, very deep into the optimization. Fin shape, fin profile, nose cone shape, weight, etc. will all have much bigger effects on the rocket's altitude.

Yep.... I need to read that book. [EDIT - Found a PDF download and read it through. Yeah.... wfcook had it right (I thought/think), and my first run through Hoerner increases my confidence. But that book is dense.... I will need to read it in detail several more times.]

I tend to fall on the @wfcook side of the discussion. Fin fillets should likely be no larger than required for structural demands, and if properly executed will be close enough aerodynamically... The weight and frontal aspect reduction may well plus up any of the aerodynamic losses.
Frankly, I am not convinced that the aerodynamics are all THAT compromised with a smaller radius, less material, etc.

I am sure that other factors have more effect, but this is something over which I have control now.
"I" control the fillet radius and the filleting material.
A lot of that other stuff, I cannot easily control at the moment.... maybe for a post LVL 3 project.
My focus is on learning the material (science/math) while I am also learning additional skills, techniques, et al. so that I will have a full toolbox to use on the more complicated stuff.

In the meantime, if I can reduce my epoxy usage and the weight on my air frames attributable to OVERuse of adhesives.... Yea for me!

 

[cautery]

I thought today was going to be an "All Building; All Day" kid of day, but Stewie (our 16 year old cat) apparently has decided that CLOSE to his litter box is "close enough". So I was interrupted for cleaning duties. Turns out OLD cats, especially males, need a BIGGER (longer) littler box.... who knew. Now I have to build one, because we already have the biggest, commercially available, covered litter box. Grrrr....

Anyway, I did get a few things done... Pictures and descriptions below:


LEFT: Hole, through, 0.25" 1 EA. - Simple plywood piece used as a backup on a drill press using a HSS stub bit from McMaster. No tearout or blowout visible without magnification. "Double backing" might have reduced it to zero. (placing a sacrificial piece BOTH under and on top of work-piece and drilling through all three at once.
RIGHT: "Ready" to set the PEM into the fiberglass plate (same approx. thickness as air frame).


LEFT: THIS is what happens when you try to pull a PEM into a fiberglass panel with a flat-head screw and a plastic rail button. It doesn't pull, and it ruins the rail button. What was I thinking.
RIGHT: Used an 8-32 pan head screw and unknown sized washers (but they are a SNUG, almost interference fit on the screw). They are punched washers, so have a round and a sharp side. If you aren't going to lap them flat, then make sure the ones touching the plate are round side forward. Sucked it right up even with the tiny socket head cap screw.


LEFT: A second PEM is placed next to the installed one to see the comparison of washer height vs. PEM insertion flange. When inserting these or using them for retention during installation/curing, I do NOT want the screw to protrude, because the hole will be covered to prevent epoxy intrusion.

So, I START an insertion sequence with ONE washer removed from the stack, so the screw will catch enough threads. About one full revolution, and you can remove the screw, add the last washer, reinstall screw and finish setting the PEM flush.
A LOT of other items occurred to me while going through this exercise, especially the differences involved in setting them in a tube. Wish I had some spare to test on. More later on that and other stuff like using an end mill after curing to cut a flat spot over the PEM to get the bottom lip of the rail button OUT of the air flow, et al.

RIGHT: 8-32 PEM with my "Installation Tools". Washers are great and better, they were free. But I will likely replace the stack with a spacer of the same dimensions, and lap the finish washer flat on the sharp side to keep the whole stack true.


Above: And finally, a comparison shot between a pristine rail button and one that some moron tried to use as a puller spacer!


Maybe now I can get something else done (like do all the air frame drilling like I planned), if my geriatric cat can keep everything INSIDE the litter box.

PS - I realize that none of this is "new". I am just documenting what I do, how, why, et al. as sort of a notebook. Anything I don't write down, I will eventually "lose". AKA - forget and have to relearn.

 

[Roo59]

Like your thinki

While I cannot possibly make cheap Chinese tools as cheaply as the Chinese, I will still be making my own.
I prefer the Delrin (acetal) over stainless steel for the ball ends. I think the acetal sheds the adhesive better and makes a smoother pull. And I can get them in so many more diameters/radii. I'll have to do some testing I'm sure. Not a big fan of the large diameter handle either.... or the silicone sleeve.

I "get" cheap.... but I prefer to have a tool that "fits" me. I'm not just using these on the fins.

I THOUGHT that I would NOT like the "all-thread" as a handle, but I find that the threads provide grip and are not uncomfortable. And I THOUGHT the small 4-40 diameter would bother me. It does not. I actually think having the smaller diameter and less interruption on the back end of the sphere is "better". I have a lot more visibility. This will come in handy for internal fillets with a reach. Also less chance that I will get material around the ball and onto the handle. And I can just dump them into pretty much whatever solvent concoction I want for cleanup.

Currently using an aluminum 4-40 because that's what I ordered for something else and I had it around spare. With use, I thing I will prefer the 4-40 over larger, BUT the aluminum is just a tad flexible for a pull where you need to "reach" very far. I will likely change the handle material to something else.... ideally 316 or 304L stainless, but not likely due to cost.

FYI - I am a student of the tools and process of creating. I often get greater enjoyment from the production than I do the product.

I like your thinking. It is a hobby after all!
You might find some suitable rod material at an R/C hobby shop.

 

[cautery]

I like your thinking. It is a hobby after all!
You might find some suitable rod material at an R/C hobby shop.

Welcome to TRF! You will find more than you can possibly absorb here.
Folks are generally quite well-behaved. Mostly, you get what you give here. If you're cool; folks will be cool back at ya. If you are a raging basshole, then you will likely reap what you sow.

In my area, there are hardly any Hobby Shops remaining.... No RC aircraft shops, train stores, rocketry, nothing..... unless you want to go to Hobby Lobby or Michaels and do crafts or make frames...

A lot of us here use McMaster-Carr, a supply house that has pretty much everything most folks can imagine.
I will absolutely be able to find the "right" rod material.... just need to pick it out. Probably stick with 4-40 for tools </= 12 inches. MIGHT go to 6-32 for longer rods for reaching way deep into an air frame.

Be well!

 

[cautery]

I set the drill press up last night and rehearsed the procedure for drilling the holes in the booster tube for the PEM nuts to back the rail buttons. It was perfect. BUT, I was a bit tired and was having a hard time focusing my eyes at close distance (spotting the centers).

So I took a break for about 6 hours... BUT, I didn't sleep. Yeah, it's an issue.

Anyway.... do not work on important/detailed/precision work unless you are fully rested. I made a goofy mistake, and the ONLY way to explain it is fatigue.

Here's the setup, the mistake, and the fix...


LEFT: Booster tube clearly marked for forward rail button drill center. If you look close, you can see that I have already installed the "backer" tool.
RIGHT: Since the backer had to go so far into the tube, I chose to insert the shims from opposite ends. Beveled them with a knife. Used the handle of one of the sanding tools to hold the backer in place while I inserted each shim.



LEFT: Pointed up at the 320 watt fluorescent light fixture to see if there is any "daylight" between the tube and the backer at or near the drill site.
RIGHT: Pointed to allow the light to highlight the pencil line drawn down the centerline between Fins 2 & 3 (aka: the "back" of the rocket). It all looks great.



LEFT: So, I set up this drill operation using a countersink bit because it has that nice sharp point and is approximately the same length as short 1/4" bit.
RIGHT: The good news is that the shimmed backer tool (aka: 2" PVC coupler and some wooden shims) worked wonderfully. The hole cut square and sharp with no observable blowout/tear-out.



LEFT: You can feel AND see when the bit STOPS cutting fiberglass and is fully in the PVC. What you can't see very well here, is that SOMEHOW after setting this drill op up and checking it and rechecking it some many times over 6 hours.... I managed to drill the hole with its center NOT on the rail button line I drew specifically for this operation. That's the bad news.... Oof!
RIGHT: Some more good news is that I already repaired it... well, almost already repaired it. I used WS 105 resin and 205 hardener. After a minute or two mixing, I added less than 1 drop of rocketpoxy red dye and 4 teaspoons of 206 silica as a filler to try to simulate the resin/fiber matrix. I used the Ziploc to cover it and hopefully approximate the shape better and avoid a flat spot.



ABOVE: Here you can see that the holes are not on the same line. I waited until the leftover epoxy cured in the mixing cup, but the repair was not leathered yet... I guess the Ziploc layer on both sides of the repair retarded the curing. In any event, I cleaned up what I could before it hardened. I will need to block sand and add fairing/filling compound to bring it back completely flush with the tube. But it will work....
Hate that I made a bone-headed mistake, but at least "first blood" has been drawn and I can relax a little and try to enjoy the build.

Time for a nap...

Bottom Line though.... the tool works. Setup worked. Procedure worked.... repair worked/is working. All good except for not knowing how I managed to rotate the tube AFTER it was set, checked, and verified.

 

[pathtouch]

I thought today was going to be an "All Building; All Day" kid of day, but Stewie (our 16 year old cat) apparently has decided that CLOSE to his litter box is "close enough". So I was interrupted for cleaning duties. Turns out OLD cats, especially males, need a BIGGER (longer) littler box.... who knew. Now I have to build one, because we already have the biggest, commercially available, covered litter box. Grrrr....

We gave up on litter boxes and use use concrete mixing tubs from Home Depot. Maybe an option for you?

https://www.homedepot.com/b/Buildin...Accessories-Concrete-Mixing-Tubs/N-5yc1vZaq89
Nice work on the punisher so far btw!

 

[cautery]

Nice work on the punisher so far btw!

Thank you.

 

[cautery]

Spent most of the day fixing my drilling mistake.... but it was not all bad. Learned a lot about West Systems 105/205 and 406 silica.

LEFT: Base fill. Scrubbed with NEW green pad and hot-ish water until I could see the break.
RIGHT: At this angle, it's hard to see. Pretty happy with the color match. Needs at least one more fill layer...



LEFT: Second fill, pre-sanding. Still got a little "tooth" to it. Needed a 3rd fill anyway. The voids will give it something to hold onto.
RIGHT: In the lighted area, you can clearly see the hole, but the "mistake" is hard to photograph.... It IS there though. <grrrrr>



LEFT: Terrible photo, but I did just barely get the light right to see the reverse casting job on the fill. At 5:00 to the actual hole, you can see a lighter spot. It's not that color. That's just the couple of thousandths of an inch discontinuity with the rest of the inner walls.
RIGHT: 3rd fill layer on exterior. I overfilled on purpose in hopes of this being the last fill layer...



ABOVE: Block sanded back with wet 220 grit. You can see it if you know what to look for and where for sure. I am probably not going to fill again, but I likely will get some red glazing putty to try and get it to dead flat and smooth..... like the rest of the tube.


BELOW: Annnnd, for better or worse, the vent band is officially bonded to the av-bay/coupler. I verified the setup a dozen ways and tried to find the best chance for the vent band to centralize around the av-bay tube so there will not be any "proud edges" between the vent band and the booster tube or the nosecone.... THAT will make me sad!

Now, I am gonna go try and sleep, to hopefully prevent another fatigue-inspired mistake.

 

[Hobie1dog]

nice repair

 

[cautery]

Harnesses to Motor Tube Bonds - Using 2 each, 1-loop harnesses at 180 degrees separation. This is the first side...


LEFT: Cleaned motor tube thoroughly with 99.9% Isopropyl Alcohol and a NEW green pad followed by a rinse and 220 wet sand. Verified water break on entire exterior. Scrubbed again with alcohol and green pad. Rinsed in de-ionized water and dried. Marked #1 fin line with aluminum channel.

Indexed front CR on the key line and marked the harness notches on the tube. Extended left and right to the ends of the tube. Marked the #2 and #3 approx fin centers using the CR vent holes (turned it 180 degrees). Marked out the 0.125" NOGO area for the fin roots. Then marked off half the distance between the harness strip area and the fin NOGO line.

Taped off the entire MT to cover everything that is not intended to get adhesive on it. Cut and taped a 1 gallon Ziploc bag to use as a non-stick cover for the bond and made sure the plastic was taped on right at the NOGO line.

RIGHT: Mixed up 12.38 grams of West Systems 105/205 with 406 Silica filler. Used a chip brush to paint the epoxy on the "GO" area to pre-wet for more consistent bonding. Moved the harness and clamps back in place and tensioned the harness under the clamps and indexed the tape wrap at the aft end to set harness ultimate length. Using a narrow stick, I spread the thickened epoxy over and around the harness with the goal of wetting the Kevlar out thoroughly and working all the air out. Pulled off as much unneeded adhesive with the stick as possible.



LEFT: Carefully wrapped the plastic around and secured it snugly. Using the plastic as a shield, I then worked the epoxy back and forth, forcing it into the Kevlar and into the final shape I wanted. This is mostly a rehearsal and a stepping stone toward bagging this type bond in the future to get the strongest bond with the least adhesive weight/volume. Used my fingernail at the taper lines to provide a "parting" line.

RIGHT: It worked pretty good. A few small voids that don't appear to compromise the overall bond strength. I think the bond vastly surpasses the strength of the harness. We'll see how it looks with the tape removed after the second bond is cured. Just need to refine the technique.



LEFT: First bond... A little wavy as indicated by the white peaks and valleys. Otherwise, the tape pulled right off and cut good glue lines.

RIGHT: Second bond... Much smoother, more consistent, fewer voids. Technique improved.
Have to scrub the entire tube clean again with a fresh green pad, acetone, and then alcohol (masking tape adhesive, et al.)
Then it is on to the centering rings.

 

[cautery]

Forward Rail Button Broaching Nut (aka: 8-32 PEM Nut)

LEFT: Handle of sanding tool & plumber's putty used to mount nut for insertion into tube. Fastener has been scrubbed in 99.9% Iso, dried, and masked for embedding in epoxy.

RIGHT: Top view. Note the blue tape that has been added to exclude adhesive from the threads. The tape has been closely trimmed back over the shoulder/radius on the nut to allow the epoxy to grab the shoulder.



LEFT: Partially pulled into place. Very important to get it started as straight as possible to improve final result.

RIGHT: The "puller" which is as described earlier, just a pan/truss head screw, stack of washers, and the hex key.



LEFT: First pull.... partial set. I am a firm believer that you need to go SLOW when putting these in. Get the fiberglass "used to the idea" of getting out of the way of the splines. 1) Put it in a bind; let it set. 2) Take the bind off' let it rest. 3) Inspect. Lather, rinse, repeat... I use 5-15 minute rest periods.

RIGHT: Finally.... IF you are patient, it will, after a number of cycles, draw up tight to the two outer edges (arc tangent). I pulled mine to this point and then tweaked it approx. 1/16th additional turn and let it rest one last time.

When you let off the last time it should stay set flush and have reduced stress locally to the fastener and less distortion of the tube diameter. No cracking, splintering, et al. Nice and solid, and ready for epoxy encapsulation. You will need to block sand the outside of the tube to help remove the very, very slight remaining distortions. Alternatively/additionally, you could jig it up in a drill press (or mill) and mill a flat over the clinch nut to receive the flat base of the rail button.



LEFT: Interior view of Forward Rail Button "broaching nut" (aka: PEM, self-clinching net, et al.) Note that there is no daylight under the nut even strongly backlit. Next step is to encapsulated the nut and bond it to the inner wall of the air-frame.

RIGHT: Interior oblique overhead of epoxy "puddle" over broaching nut (PEM). It is actually, thickened 105/205 that was placed over the fastener with a mixing stick lashed to the end of a long dowel. The wetted patch is a rough rectangle. The tube on either end was protected with rolled up brochure paper, the belly of the roll being placed along fastener axis. Should have got an image.... apologize.



LEFT: Broaching insert nut cured, and forward rail button installed.

RIGHT: Closeup of forward rail button from the side of the air-frame. Still wondering if I want to take the trouble to mill a flat here.

Need to refine the adhesive delivery procedure. The shields work well. Next time will consider using purpose cut templates for closest shields to reduce wetted patch size. Need to create rigid and flexible long working tools.

 

[cautery]

Centering Rings - Aft CR must be fixed first, to index it with the motor retainer. Then, the fins can be clamped in place with the front centering ring and ring marked for and aft.


LEFT: Aft CR located and marked both sides using retainer. CR pulled back to reveal CR to MT direct contact area. Wet this area out with unmodified 105/205 epoxy. Rotating ring back and forth to wet out inner face, put CR back in place and re-indexed with retainer. Added o-rings as epoxy dams.
Repeatedly cleared fin root NOGO areas with toothpick until adhesive gelled.

RIGHT: Waiting on aft CR tack bond to cure in anticipation of filleting the aft CR on the forward face with thickened 105/205. Aft face of aft CR will receive ONLY JB Weld on CR and retainer mount.



LEFT: Aft Centering Ring, forward face. Fillets at other than wing root locations. WS 105/205 & just enough 406 Silica so it would hold the fillet. Cleared and cleaned the vents.

RIGHT: Motor tube is ready to begin the installation procedure. It's straight forward EXCEPT I have to set the real Rail Button briaching nut (PEM) BEFORE I put the aft CR and retainer into the air-frame. In internal fillets will finish out the CR inboard face fillets. The forward face of the forward CR will be pored in place from the top of the booster tube. The aft face of the aft CR will get sealed in when the retainer is bonded in with JB Weld.

 

[cautery]

HELP!?! - Slots in Body do not FULLY line up with the fin jig.

OK.... so I have hit my first "bump in the road".

Either my booster tube is slotted a bit wonky, or BOTH my WM 3-fin jigs are wonky. Whichever... I need to figure out how to proceed.
Pictures below... I have a few ideas on where to go from here, but I will reserve my opinion until I hear (hopefully) from some more experienced folks.


LEFT: "#1 Fin" slot on body tube lined up "centered" with "#1" slot on Wildman Rocketry 3-fin jig. Yes, I put the jig on the body tube opposite end and rotated it a few times until it smoothed out the inner diameter and closed the daylight 360 degrees around. The jig IS sitting flat. I verified it with squares, et al. So far, so good.

RIGHT: Rotating counter-clockwise to MY #2 fin..... That my friends is what we call a "misalignment". Hmmmm.... Let's look at the last one...



ABOVE: Hmmmmm.... About the same.... maybe a little worse...
OK, so this is my diagnosis. Slots # 2 and #3 are cut parallel to each other 120 degrees of separation. The #1 slot is parallel, but is cut at slightly more than 120 degrees relative to MY #2, and slightly LESS than 120 degrees relative to MY #3 fin.

To me.... this is a SIGNIFICANT fault in the dimensions of a critical area on the air frame.

Ideas?

 

[Banzai88]

I've had a few fiberglass tubes from both WM and RW that were off perfect alignment as yours are. I made jigs from foam board and moved forward with building.....the fly just fine.

The only tubes that I've ever had that were perfect every time (4 out of 4 products) were from MAC

 

[cautery]

I've had a few fiberglass tubes from both WM and RW that were off perfect alignment as yours are. I made jigs from foam board and moved forward with building.....the fly just fine.

The only tubes that I've ever had that were perfect every time (4 out of 4 products) were from MAC

I guess a tube slotting jig just got put on the list of needed tools... I'm too OCD for those kinds of tolerances.

 

[boatgeek]

I guess a tube slotting jig just got put on the list of needed tools... I'm too OCD for those kinds of tolerances.

For this build, reslotting the tube means a huge amount more work than making a foamboard fin alignment guide and living with the misalignment. The tiny off-120 degrees on slot #1 is insignificant to the flying characteristics and probably won't even be visible. I know you'll know it's there, but you'll also know that you had to expand the slot in the body tube, make fillets bigger than you planned, refill that section of body tube, etc. etc.

For the next build, by all means make your own slotting jig so you get it just right.

 

[cautery]

For this build, reslotting the tube means a huge amount more work than making a foamboard fin alignment guide and living with the misalignment. The tiny off-120 degrees on slot #1 is insignificant to the flying characteristics and probably won't even be visible. I know you'll know it's there, but you'll also know that you had to expand the slot in the body tube, make fillets bigger than you planned, refill that section of body tube, etc. etc.

For the next build, by all means make your own slotting jig so you get it just right.

Yes sir, that's what I meant. No way I am going to try and re-slot THIS tube... <shudder>

Yep, slotting and fin jigs are definitely on the list for NEXT build.

Yeah, I realize that as long as the fins remain parallel to EACH OTHER AND coincident with the air frame centerline that the rocket should fly straight. I suspect the clocking would only come into play if there was a guidance computer counting on the fins being where the computer was TOLD they are.

 

[StreuB1]

I set the drill press up last night and rehearsed the procedure for drilling the holes in the booster tube for the PEM nuts to back the rail buttons. It was perfect. BUT, I was a bit tired and was having a hard time focusing my eyes at close distance (spotting the centers).

So I took a break for about 6 hours... BUT, I didn't sleep. Yeah, it's an issue.

Anyway.... do not work on important/detailed/precision work unless you are fully rested. I made a goofy mistake, and the ONLY way to explain it is fatigue.

Here's the setup, the mistake, and the fix...

View attachment 550065View attachment 550066
LEFT: Booster tube clearly marked for forward rail button drill center. If you look close, you can see that I have already installed the "backer" tool.
RIGHT: Since the backer had to go so far into the tube, I chose to insert the shims from opposite ends. Beveled them with a knife. Used the handle of one of the sanding tools to hold the backer in place while I inserted each shim.


View attachment 550067View attachment 550069
LEFT: Pointed up at the 320 watt fluorescent light fixture to see if there is any "daylight" between the tube and the backer at or near the drill site.
RIGHT: Pointed to allow the light to highlight the pencil line drawn down the centerline between Fins 2 & 3 (aka: the "back" of the rocket). It all looks great.


View attachment 550070View attachment 550071
LEFT: So, I set up this drill operation using a countersink bit because it has that nice sharp point and is approximately the same length as short 1/4" bit.
RIGHT: The good news is that the shimmed backer tool (aka: 2" PVC coupler and some wooden shims) worked wonderfully. The hole cut square and sharp with no observable blowout/tear-out.


View attachment 550072View attachment 550073
LEFT: You can feel AND see when the bit STOPS cutting fiberglass and is fully in the PVC. What you can't see very well here, is that SOMEHOW after setting this drill op up and checking it and rechecking it some many times over 6 hours.... I managed to drill the hole with its center NOT on the rail button line I drew specifically for this operation. That's the bad news.... Oof!
RIGHT: Some more good news is that I already repaired it... well, almost already repaired it. I used WS 105 resin and 205 hardener. After a minute or two mixing, I added less than 1 drop of rocketpoxy red dye and 4 teaspoons of 206 silica as a filler to try to simulate the resin/fiber matrix. I used the Ziploc to cover it and hopefully approximate the shape better and avoid a flat spot.


View attachment 550074
ABOVE: Here you can see that the holes are not on the same line. I waited until the leftover epoxy cured in the mixing cup, but the repair was not leathered yet... I guess the Ziploc layer on both sides of the repair retarded the curing. In any event, I cleaned up what I could before it hardened. I will need to block sand and add fairing/filling compound to bring it back completely flush with the tube. But it will work....
Hate that I made a bone-headed mistake, but at least "first blood" has been drawn and I can relax a little and try to enjoy the build.

Time for a nap...

Bottom Line though.... the tool works. Setup worked. Procedure worked.... repair worked/is working. All good except for not knowing how I managed to rotate the tube AFTER it was set, checked, and verified.

Dude, you think you're the only person who has full diameter epoxy plugs in their FG airframe rockets?? One of mine has 5 FIVEEEEEEEEE plugs in the airframe!!! LOL!!!!

6 minute JB weld and a sandwich bag like you used, is actaully faster and easier from my experience. Once the JB weld has gone hard leather, hit it with a rasp to take it down a bit and keep working. It cures so fast and is so strong that you just fix the mistake and keep working, no stopping the build.

6 minute JB weld has become one of my secret weapons. Its the best adhesive for tacking things in place as well. I no longer use CA and accelerator spray to freeze joints. Its never good enough anyways...... 6 min JB weld tacks on a joint. In 10min its not going anywhere and in 20min its really not going anywhere. Its amazing stuff and you can mix it in toothpick sized quantities for the tiniest of jobs.


Excellent build so far!!

 

[cautery]

Dude, you think you're the only person who has full diameter epoxy plugs in their FG air-frame rockets?? One of mine has 5 FIVEEEEEEEEE plugs in the airframe!!! LOL!!!!

Thanks for that!

6 minute JB weld and a sandwich bag like you used, is actually faster and easier from my experience. Once the JB weld has gone hard leather, hit it with a rasp to take it down a bit and keep working. It cures so fast and is so strong that you just fix the mistake and keep working, no stopping the build.

6 minute JB weld has become one of my secret weapons. Its the best adhesive for tacking things in place as well. I no longer use CA and accelerator spray to freeze joints. Its never good enough anyways...... 6 min JB weld tacks on a joint. In 10min its not going anywhere and in 20min its really not going anywhere. Its amazing stuff and you can mix it in toothpick sized quantities for the tiniest of jobs.

Hmmmm..... I'll store that away for later use. I am of course using JB Weld ORIGINAL for the motor retainer, and am contemplating using it for tacking the fin roots in due to its higher temp rating, ultimate bond strength, ability to "read" the bond line from inside the motor tube, and most importantly, the long open/working time to get the fins PRECISELY where I want them.

But that is essentially 3 DAYS to tack 3 fins (properly).
Wonder what the strength and temp ratings are on the 6 minute?

I just noticed last night that my two rail button holes are "off" (still). It is the tiniest amount, but it bugs me still. (I REALLY need to get a REAL round stock jig.... the wooden one I am using is not accurate enough.)

The forward one (the one I re-drilled and repaired) is dead nuts on.... The aft hole is clearly not bisected exactly by the line that bisects the fin slot. I don't think it is enough to be significant, but it bugs me. IF it causes issues, I can just remove the buttons, drop a set screw in the holes, and use my fly-away rail guides.

Excellent build so far!!

Thank you! I'm trying my best considering the limitations under which I am operating.

 

[Banzai88]

I just noticed last night that my two rail button holes are "off" (still). It is the tiniest amount, but it bugs me still.

Lots and lots and lots of good ole boys been doing rocketry builds with lots of things MORE than a 'little' off for a long time.....and things fly just fine...odd rocs not withstanding!

It'll be OK!

 

[KenECoyote]

Good idea that if you're ocd/anal retentive about things being perfect to first use some tube marker (like used for marking lugs & rail buttons...door frame, angle stock, etc.) and mark lines down to confirm that fin slots are parallel before you glue in fins.

I do agree that it shouldn't make much difference (if any at all noticeable) in performance.

However, years ago I got a fg kit with a motor tube that was cut off square and I didn't notice it until I JB welded on the retainer and had the rocket sitting up on it....leaning tower rocket.

I mentioned it and was told that everyone should square parts as a first step of fg rocket build, yet I hadn't heard of such myself. I was so annoyed that I gifted the rocket to a friend and built another. Does it affect performance? Not at all. Did it bother me? Yes.

Lesson here is to check parts and don't assume it was done exactly (or correctly)... I've seen this in many rocket kits and parts.

 

[cautery]

Good idea that if you're ocd/anal retentive about things being perfect to first use some tube marker (like used for marking ligs & rail buttons...door frame, angle stock, etc.) and mark lines down to confirm that fin slots are parallel before you glue in fins.

I do agree that it shouldn't make much difference (if any at all noticeable) in performance.

However, years ago I got a fh kit with a motor tube that was cut off square and I didn't notice it until I JB welded on the retainer and had the rocket sitting up on it....leaning tower rocket.

I mentioned it and was told that everyone should square parts as a first step of fg rocket build, yet I hadn't heard of such myself. I was so annoyed that I gifted the rocket to a friend and built another. Does it affect performance? Not at all. Did it bother me? Yes.

Lesson here is to check parts and don't assume it was done exactly... I've seen this in many rocket kits and parts.

Yes sir.... In this case, the slots appear to be parallel.... No problem with that at all. ONE of the slots is merely clocked a degree or so OFF the 120 degrees it should be from the others. I checked than for parallelism when I marked everything up.... It never occurred to me to check the clocking.... I guess it should have... and most certainly WILL be on my list from here on out.

Does it affect performance? Not at all. Did it bother me? Yes. <----- Me... this is me.... I "get" this. Most do not.

Lesson RE-learned.... NEVER assume. Always verify. Everything.

 

[Banzai88]

Yes sir.... In this case, the slots appear to be parallel.... No problem with that at all. ONE of the slots is merely clocked a degree or so OFF the 120 degrees it should be from the others. I checked than for parallelism when I marked everything up.... It never occurred to me to check the clocking.... I guess it should have... and most certainly WILL be on my list from here on out.

Does it affect performance? Not at all. Did it bother me? Yes. <----- Me... this is me.... I "get" this. Most do not.

Lesson RE-learned.... NEVER assume. Always verify. Everything.

Believe me, 'we' get it, too. Just that unless you're cutting/slotting your own tubes, it's sometimes necessary to accept from even the best and most beloved of commercial vendors.

And cutting slots in fiberglass tubes without certain gear is something of an artform.

 

[cautery]

Believe me, 'we' get it, too. Just that unless you're cutting/slotting your own tubes, it's sometimes necessary to accept from even the best and most beloved of commercial vendors.

And cutting slots in fiberglass tubes without certain gear is something of an artform.

Absolutely!

And just to keep the record straight..... I am most decidedly NOT criticizing ANYONE, especially the vendor. Stuff happens. "I" am the only one at fault here! I KNOW better. I should have caught it from the outset. My deal.... totally.

 

[KenECoyote]

Yes sir.... In this case, the slots appear to be parallel.... No problem with that at all. ONE of the slots is merely clocked a degree or so OFF the 120 degrees it should be from the others. I checked than for parallelism when I marked everything up.... It never occurred to me to check the clocking.... I guess it should have... and most certainly WILL be on my list from here on out.

Does it affect performance? Not at all. Did it bother me? Yes. <----- Me... this is me.... I "get" this. Most do not.

Lesson RE-learned.... NEVER assume. Always verify. Everything.

Ah apologies...the pictures themselves make it look like the fins are misaligned/angled. A degree off is acceptable imo and I wouldn't expect a rocket kit to be more precise than that in this situation.

 

[waltr]

Check the fin fixture.
Go to https://www.payloadbay.com/index.php?page=Tools&action=FINGUIDES
and print out a fin guide. Then lay the WM guide on top of the print out to compare.

As others stated. If fin slots are parallel to BT then all is good. Maybe just file out a side of the slot that is off so the fin fits in the guide. Internal & external fillets will fill in the small gap..

 

[StreuB1]

I tack my fins on with 6min JB weld all the time. I would not worry about the capabilities of 6 min vs original JB Weld. Both will outperform what you need them to do, most certainly.

Tack all (3) on in one shot, slide the alignment guides on, let it sit for 30min. Slide the guides off, let it sit an hour. Then do your permanent fillets. You should be able to do all of them in (1) sitting. JB Weld is zero sag so just do it all at once. You should be able to build the entire thing nearly in one shot.