Another ACME Spitfire build thread?
- Thread starter Blast it Tom!
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Got it downloaded, thanks!
Have to what?
Yeah, that was a test, and you passed! I hope I can do justice to Bill's marvelous work. I've DL'd a 3D Spaceman spiff, but have not found a suitable 3D Hobbes, and unfortunately, there is really no way for me to model him myself, time-wise or ability-wise. And I have zero experience with 3D printing, how these things scale, what material to use, etc. So that is a whole other angle. I thought about having the cockpit in the nose. Putting a window there is its own challenge. Also I have to find some way to exclude Susie Derkins. After all,
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Now that my happy dance has ended, and I let my mind wander it occurs to me that Spaceman Spiff's ship could be a great saucer model.
If only I knew how to make saucers from scratch ... guess I better go browse the forum and figure that out. And add two more rockets to the build list because Calvin and Hobbes were my childhood entertainment more than cartoons because I could take them with me on camping trips where luckily I didn't get as much character as Calvin did. Now if only the grown up stuff could get out of the way and let me build rockets.
Watterson was in a class by himself, to be sure. I assume you have the 3 volume anthology? I feel he might just have been mistaken (but certainly within his rights) at not marketing as per Schultz and Peanuts; obviously to this day folks are deriving great joy from our hero here. I have plenty of Charlie Brown & Snoopy in my office, but some Calvin & Hobbes would be nice, too!
Hope you enjoyed your Happy Dance!
I don't have the anthology, but I do have pretty much every individual book that was published, which my kids now claim ownership of.
I always felt like the lack of official merchandise/movies/comics/etc. wasn't fair as a kid, but as an adult I've realized it was totally in his control, and it has kept Calvin and Hobbes in a more special place because the worst thing that can happen to them is they reprint a fancy leather bound anthology. I don't have to worry about them getting updated, re-imagined, or turned into a live action movie.
Of course this means my office is filled with toy trucks instead of stuffed tigers and wagons.
Well, I wouldn't mind a knick-knack or two! But, as you say, it was his call. Bless the man, he really gave us a wonderful gift.
So anyway, long before I can get to the finishing and theme, I gotta build the thing! Now where was I... Yup! We're now ready to glue the first outer tube segment to the bottom centering ring. Two issues here:
1. The instructions said make the end of the tube flush with the end of the motor hook. Well, I have no motor hook...
2. By all means you want this 1st tube segment concentric with the inner BT-50 motor tube at both ends.
My solution was to position the hook where it would have been, measure the extension from the end of the motor tube, cut a piece of dowel to that thickness, and set the motor tube on that. I had measured 11/32" (0.344") and the dowel came out 0.347". Not so bad...
At this point I sanded the end of the motor tube and dry-fitted the motor retainer. This will be glued to the tube with JB Weld later. It's much easier to assure that the fit is correct now.
Now the tube segment can be glued, with centering ring #2 placed dry simply to provide concentricity.
No glue on #2 ring yet!
So anyway, long before I can get to the finishing and theme, I gotta build the thing! Now where was I... Yup! We're now ready to glue the first outer tube segment to the bottom centering ring. Two issues here:
1. The instructions said make the end of the tube flush with the end of the motor hook. Well, I have no motor hook...
2. By all means you want this 1st tube segment concentric with the inner BT-50 motor tube at both ends.
My solution was to position the hook where it would have been, measure the extension from the end of the motor tube, cut a piece of dowel to that thickness, and set the motor tube on that. I had measured 11/32" (0.344") and the dowel came out 0.347". Not so bad...
At this point I sanded the end of the motor tube and dry-fitted the motor retainer. This will be glued to the tube with JB Weld later. It's much easier to assure that the fit is correct now.
Now the tube segment can be glued, with centering ring #2 placed dry simply to provide concentricity.
No glue on #2 ring yet!
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After the glue dried on the #1 centering ring to #1 tube segment joint, the joint was filleted on both sides. I fashioned a stand from an old CD bulk case (remember those?!) to do the bottom fillet and for any other "nose down" work that it might require.
Then I masked off the end of the motor tube where the Aero Pack motor retainer will mount and did the fillet.
Doing the topside fillet on this certainly wasn't as easy, but the silicon glue spatula seen earlier helped.
Then I masked off the end of the motor tube where the Aero Pack motor retainer will mount and did the fillet.
Doing the topside fillet on this certainly wasn't as easy, but the silicon glue spatula seen earlier helped.
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Next came the fixed part of the motor mount. The instructions say to clean the inside of the retainer with acetone to assure a good bond to the tube. Then mix your JB Weld (the slow stuff, not the quick) and put a thin coat on both the tube and the retainer. Below shoes 'way to much JB Weld!
Carefully applied to the ridged fit area on the retainer:
And the tube:
Then I masked the retainer so that I can paint the area later, and mounted it to the tube, twisting it to distribute the JB weld evenly through the joint:
You have to clean up and be sure the JB Weld is not where it shouldn't be - the above picture is before I cleaned the inside. The outside you can just wipe with an acetone-moistened rag. Not too much, both for the epoxy's sake and your innards - make sure you are using good ventilation and/or respiratory protection.
Carefully applied to the ridged fit area on the retainer:
And the tube:
Then I masked the retainer so that I can paint the area later, and mounted it to the tube, twisting it to distribute the JB weld evenly through the joint:
You have to clean up and be sure the JB Weld is not where it shouldn't be - the above picture is before I cleaned the inside. The outside you can just wipe with an acetone-moistened rag. Not too much, both for the epoxy's sake and your innards - make sure you are using good ventilation and/or respiratory protection.
At this point I want to acknowledge someone who gave us all some very good advice back about 10 years ago..
@Gus, whose avatar gives my heart a pang every time, wrote this well-thought-out advice on @Green Jello's build thread. And then as well, in his 6 Spitfire gallery post, he showed a wonderful method for positioning the centering rings.
The directions tell you to practice until you can do Step 11 quickly and accurately before you use glue. Well, uh... they also tell you to NOT glue the #1 centering ring in like I did in Step 9... duh.
So anyway, Gus's picture showed 3 straight pins into the edge of the centering ring. The ring is .050" thick. So I got a .025" feeler gage and held it beside the ring, then carefully, making sure everything was held down flat, pushed the pins in about 1/4". Now the bottoms of these 3 pins must be very close to the mid-plane of the centering ring. It worked well!
Thanks, Gus! I'm a great fan of fixtures...
So I then put my used D case into the top of the motor tube so that I could quickly upend it once I had the glue on and everything in position. I traced the motor tube (BT-50) so I'd know where to put the glue. I removed the centering ring, and applied the glue as quickly as I could. I positioned the centering ring (remember to align the alignment mark with the red line), resting the pins on the #1 body tube section. Then I upended it onto the CD case stand.
At this point it's easy to go around with the point of your razor knife and adjust any places on the ring that may be too deeply or shallowly into the joint. Then just let'er dry; hopefully the glue will run down into the joint and make a kind of fillet.
@Gus, whose avatar gives my heart a pang every time, wrote this well-thought-out advice on @Green Jello's build thread. And then as well, in his 6 Spitfire gallery post, he showed a wonderful method for positioning the centering rings.
The directions tell you to practice until you can do Step 11 quickly and accurately before you use glue. Well, uh... they also tell you to NOT glue the #1 centering ring in like I did in Step 9... duh.
So anyway, Gus's picture showed 3 straight pins into the edge of the centering ring. The ring is .050" thick. So I got a .025" feeler gage and held it beside the ring, then carefully, making sure everything was held down flat, pushed the pins in about 1/4". Now the bottoms of these 3 pins must be very close to the mid-plane of the centering ring. It worked well!
Thanks, Gus! I'm a great fan of fixtures...
So I then put my used D case into the top of the motor tube so that I could quickly upend it once I had the glue on and everything in position. I traced the motor tube (BT-50) so I'd know where to put the glue. I removed the centering ring, and applied the glue as quickly as I could. I positioned the centering ring (remember to align the alignment mark with the red line), resting the pins on the #1 body tube section. Then I upended it onto the CD case stand.
At this point it's easy to go around with the point of your razor knife and adjust any places on the ring that may be too deeply or shallowly into the joint. Then just let'er dry; hopefully the glue will run down into the joint and make a kind of fillet.
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Oh, you're welcome, I do appreciate it. That's the great thing about this forum, as long as you can find it!
I thought what you said was really good - everyone was telling the fellow HOW to do it, but no one was telling him WHY he should or shouldn't add the reinforcements. And every change makes a difference. If you add mass at the bottom, you have to add mass at the top - and not only have you lowered your altitude marginally, you've increased your mass moment of inertia (like having larger weights at the end of a baton), and the fins have to work harder to keep you pointed skyward. As I recall, that's a huge component of Barrowman's stability criteria, the damped oscillating response to a lateral disturbance. As well, mass additions lower speed off the rod - I say these things for the benefit of other readers.
I'd been going through the various build threads culling different ideas, as I do want to build this thing to last - it's a great demonstrator model - but you put me back on course as an engineer - tell me why before you tell me how! And you're right - Jim designed a great model, and it will do just fine.
Or, as a friend & colleague one said, "Anyone can build a bridge. It takes an engineer to just barely build a bridge!"
I thought what you said was really good - everyone was telling the fellow HOW to do it, but no one was telling him WHY he should or shouldn't add the reinforcements. And every change makes a difference. If you add mass at the bottom, you have to add mass at the top - and not only have you lowered your altitude marginally, you've increased your mass moment of inertia (like having larger weights at the end of a baton), and the fins have to work harder to keep you pointed skyward. As I recall, that's a huge component of Barrowman's stability criteria, the damped oscillating response to a lateral disturbance. As well, mass additions lower speed off the rod - I say these things for the benefit of other readers.
I'd been going through the various build threads culling different ideas, as I do want to build this thing to last - it's a great demonstrator model - but you put me back on course as an engineer - tell me why before you tell me how! And you're right - Jim designed a great model, and it will do just fine.
Or, as a friend & colleague one said, "Anyone can build a bridge. It takes an engineer to just barely build a bridge!"
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And a beautiful job like that is why I DIDN'T go with Wile E. Coyote! I just hope I can do as well with Spaceman Spiff! Very good!Looking great! I built my ACME and flew it last May! Such a great rocket kit!
Have you posted it in the gallery?
Thanks! I may have done a build thread here, not sure if I did or not. Haven’t posted to a gallery.
I love this kit and I would love to do an upscale. I do not think anyone has done an upscale build thread.
Go for it, good sir! If anyone here can do it, you can!
Now, back to reporting my slight progress. We've been really busy with fall cleanup the last couple of days, and my head's been turning this lower shroud gluing over and over - my former boss's wife gifted me with a coffee mug that said, "Hold on - Let me overthink this!"
Plus after I cut it out it was so rolled the wrong way that I set it under my CRC Handbook of Chemistry and Physics, and topped that with my 3 volume Calvin and Hobbes complete anthology, and waited... and it was still aways from flat, but more workable. I wanted to be sure to not kink this sheet in any way.
Last night I rolled it carefully into position and clamped it overnight. Hopefully we'll have a rain day and I can glue it up final.
What's been bugging me is how to get a good glue joint at both top and bottom joints. I've considered putting a generous bead at both locations and then spin it in a horizontal orientation, not so fast that the glue in the top joint would start to flow "downward" along the shroud surface, but just to distribute it evenly. I dunno. To be continued...
Hmm... I glued the tail shroud cone carefully mating the lines. And it appears to be just a hair looser than I am comfortable with.
It's supposed to be flush with the top of the inner tube section 1 on the #3 fin side, but it is then also gapping a bit at the bottom:
They say what separates a true craftsman from a casual builder is how they overcome things like this.
But meanwhile if anyone has any suggestions, feel free to post them!
It's supposed to be flush with the top of the inner tube section 1 on the #3 fin side, but it is then also gapping a bit at the bottom:
They say what separates a true craftsman from a casual builder is how they overcome things like this.
But meanwhile if anyone has any suggestions, feel free to post them!
Build up the OD of the ring incrementally with medium CA.
Or lay a bead of glue around the centering ring OD and wrap a strip of paper around it. Trim flush with a razor blade laying against the flat surface of the ring. You should be able to trim it to the thickness of the ring, or close. Sand to fit, or add another layer if needed.
Thank you both! @Pinetree, do you mean before I'd glued it into a cone? I'd considered that but thought it best to stay with the instructions. Otherwise I'd have to split/splice this one, I think. Fortunately, I scanned it, but you have to watch both scanners and printers, they're good for stretching/shrinking dimensions even if you try to print to scale. And usually such distortion is only in 1 direction!
@tsmith1315, unless I print a new cone, this seems like the (careful) way to go.
@tsmith1315, unless I print a new cone, this seems like the (careful) way to go.
And a full 10 days later, I finally worked through my over-sized shroud. For the top, I built up the contact area with first one, then two layers of extra cardstock from the kit.
Then I used the shroud pattern to cut about 3/8" (10 mm) wide arcs that would fit inside the shroud, flush with the bottom edge. You can see one laying there, I cut two and had a third from the printer paper pattern if I needed a thin shim. I didn't - it was a little tight with two layers in the shroud, so a light sanding of the #6 ring (at the base of the tube) brought it right in.
Then I used the shroud pattern to cut about 3/8" (10 mm) wide arcs that would fit inside the shroud, flush with the bottom edge. You can see one laying there, I cut two and had a third from the printer paper pattern if I needed a thin shim. I didn't - it was a little tight with two layers in the shroud, so a light sanding of the #6 ring (at the base of the tube) brought it right in.
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Now the drill is a little more routine. I was moving now, so while the glue cured on the shroud, I went ahead and attached BTS 2 and the #3 "off-centering" ring.
Be VERY careful to align the opposite type lines, i.e. if you're using red and black lines on opposite sides of the tube sections, the red line on BTS 2 meets the black line in BTS 1. And would you believe it? I put the glue around the bottom of BTS 2 and then flipped it over as I was installing it, and I'm like, "what's that glue doing at the top... OOPS!" No harm done, as I wanted to get #3 off-centering ring in place while I still had some flexibility in the lower BTS 2 glue joint.
A good fillet around the motor tube and that should be it for tonight.
Be VERY careful to align the opposite type lines, i.e. if you're using red and black lines on opposite sides of the tube sections, the red line on BTS 2 meets the black line in BTS 1. And would you believe it? I put the glue around the bottom of BTS 2 and then flipped it over as I was installing it, and I'm like, "what's that glue doing at the top... OOPS!" No harm done, as I wanted to get #3 off-centering ring in place while I still had some flexibility in the lower BTS 2 glue joint.
A good fillet around the motor tube and that should be it for tonight.
Nice build. I have not seen a metal retainer on one of them yet.
Oh, what the heck... may as well get one more on tonight... BTS 3 and "off-centering" ring 4:
Now she's looking like a.. uh... er... rocket?
By the way, that mess is a desk!
Now she's looking like a.. uh... er... rocket?
By the way, that mess is a desk!
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Thanks, Chuck. Is there any reason that a metal retainer would not be good? It seemed like a good solution for a (hopefully) "frequent flier", and one that would allow both black powder and composite motors.
ACCESS DOORS OR HATCHES
That's right. I'm ready to add the top Body Tube Section, BTS #4. BUT... I 've been puzzling how to make an access door that will allow me to put an altimeter in this segment, specifically my Flightsketch Mini. I've never made a door on the side of a rocket before, much less from scratch.
So I think I'll throw myself on the mercy of the collective expertise of the forum and see what y'all might suggest vs. the couple of ideas that have been rattling around my noggin. Latching seems to be the tough part, in my view.
Meanwhile I can cut out fins. Much thanks to anyone who contributes!
That's right. I'm ready to add the top Body Tube Section, BTS #4. BUT... I 've been puzzling how to make an access door that will allow me to put an altimeter in this segment, specifically my Flightsketch Mini. I've never made a door on the side of a rocket before, much less from scratch.
So I think I'll throw myself on the mercy of the collective expertise of the forum and see what y'all might suggest vs. the couple of ideas that have been rattling around my noggin. Latching seems to be the tough part, in my view.
Meanwhile I can cut out fins. Much thanks to anyone who contributes!
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No. Most people just use the metal clip.
So while I continue to cogitate on how to make an access hatch and mount for my Flightsketch Mini in BTS section 4, I went ahead and laid out the fins and cut them out. I was able to tighten up the layout on the balsa sheets quite a bit as compared to the directions:
That gave some nice leftovers.
Now this access hatch... my thoughts are to have it open inwards, using a torsion spring. Cut the opening in BTS #4, then cut an inside flange from that BT-70 coupler, just slightly bigger than the hatch opening.
But I'm a little concerned about the spring load not being enough to keep it shut during flight. So far, finding a way to latch such a small door is proving challenging...
That gave some nice leftovers.
Now this access hatch... my thoughts are to have it open inwards, using a torsion spring. Cut the opening in BTS #4, then cut an inside flange from that BT-70 coupler, just slightly bigger than the hatch opening.
But I'm a little concerned about the spring load not being enough to keep it shut during flight. So far, finding a way to latch such a small door is proving challenging...
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Any chance you could fit the altimeter in the nose cone?
