Gary Byrum;1640533 "The APRO" which precedes anything here and even the Mars Lander said:
APRO Lander II Build Thread
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Gary Byrum
Overstable By Design
Don't lie to these people. YOU have never been a kid! :lol: Do the math. The late 60's was over 45 years ago. YOU WERE OLD THEN!!!
All jokes aside, we were quite young and lacking some experience. AND BLESS YOUR HEART.....You always go in defense mode every time that APRO flight comes up. Sure, it looked cool...to us, it was the icon for our rockery adventures, but it was a model and a flight that created a memory that will never die. Since none of you folks were there, as I sat on the sideline, waiting for his much anticipated flight of APRO, I sorta boiled, in that, he built it before I could. So yes, I was a little jealous. So, when it screamed off the launch pad and gnarled around like a gnat with a bad case of gas and a broken wing, it plopped itself 2 feet in front of me still hissing, and I panicked with wielding legs and stomped the hell out of it in fear for my life. He'll never say it, but I think he believes I did that on purpose. :tongue:
:cool2:
So gluing the big transition was a bit of an adventure.
After my good success with the stickiness of the Titebond NRND gluing the strakes, I thought it would also be good for the transition, because I knew that getting the four flaps to adhere to the big balsa ring was going to take some work. But then, in a spectacular bit of stupidity, I used the same glue for the ring around the BT80 to adhere the small end.
Sure enough, as I was wrestling with the four flaps to get the whole ring positioned, the glue on the BT80 seized up with the transition ever so slightly out of position. At that point, cursing myself, I couldn't think of anything to do at that point but just finish the job, which consisted of holding each of the four flaps (could've used a couple more hands) down against the ring.
The results were not awful, but still disappointing. The main defect is that the slot in line with the seam is not sitting flat. In this picture you can see the edge of the transition is bowed slightly upward:
And here, you can see the front of the slot is not tight against the fin, but is sitting a bit high:
I believe that when I install the muscle, I can clean this up a bit, but the fact remains that it's slightly cockeyed. I don't know how much it'll be visible in the finished model. It will probably be fine (not noticeable unless you know to look for it), but it's still disappointing because it was totally avoidable, and I had been so careful up until that point.
Nothing to do but move forward.... :sigh:
[on a brighter note: stuff I've done since then is looking good, updates to come]
After my good success with the stickiness of the Titebond NRND gluing the strakes, I thought it would also be good for the transition, because I knew that getting the four flaps to adhere to the big balsa ring was going to take some work. But then, in a spectacular bit of stupidity, I used the same glue for the ring around the BT80 to adhere the small end.
Sure enough, as I was wrestling with the four flaps to get the whole ring positioned, the glue on the BT80 seized up with the transition ever so slightly out of position. At that point, cursing myself, I couldn't think of anything to do at that point but just finish the job, which consisted of holding each of the four flaps (could've used a couple more hands) down against the ring.
The results were not awful, but still disappointing. The main defect is that the slot in line with the seam is not sitting flat. In this picture you can see the edge of the transition is bowed slightly upward:
And here, you can see the front of the slot is not tight against the fin, but is sitting a bit high:
I believe that when I install the muscle, I can clean this up a bit, but the fact remains that it's slightly cockeyed. I don't know how much it'll be visible in the finished model. It will probably be fine (not noticeable unless you know to look for it), but it's still disappointing because it was totally avoidable, and I had been so careful up until that point.
Nothing to do but move forward.... :sigh:
[on a brighter note: stuff I've done since then is looking good, updates to come]
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The rear fins, which need to fit perfectly between the bit of BT55 sticking out the back and the main fins, were a bit small. I should've oversized them a bit in the first place; easy to sand down as needed. Instead, I glued a sliver of balsa to the large end of each, and will *now* sand down to fit.
Might have been smart to do this *before* papering the fins, no?
Might have been smart to do this *before* papering the fins, no?
Time to attach the rear transition.
I took my newly fabricated double-layer version, cut the lug hole, and dry fit it:
Now that is much better. The problem was indeed that my old one was cut poorly. This is not totally surprising, since I could not print directly onto that posterboard, but had to cut out a template and then trace that template onto the posterboard and then cut *that* out. Some accumulating error there. The new one, made from the 65 lb card stock, was printed directly and was therefore pretty precise.
Also note that the seam now lines up properly with the fins, so it will be covered by one of the rear fins.
I used the Titebond NRND again, but this time was smart. I applied the glue to the big ring and to the end of the BT80 (which the transition should rest against if I got everything right), but no glue at all to the rear piece of BT55. After I got it into place, I simply filleted that joint to hold it firm.
The only slight trouble spot was the seam, which buckled up from the ring a bit:
I slopped a little more glue in there and squeezed it down. The remaining buckle should (mostly) hidden by the fin that will go on top of it. Remember the gap between the big transition and the fin will be covered by muscle later on.
It is looking very good, and seems to be pretty well supported underneath.
I took my newly fabricated double-layer version, cut the lug hole, and dry fit it:
Now that is much better. The problem was indeed that my old one was cut poorly. This is not totally surprising, since I could not print directly onto that posterboard, but had to cut out a template and then trace that template onto the posterboard and then cut *that* out. Some accumulating error there. The new one, made from the 65 lb card stock, was printed directly and was therefore pretty precise.
Also note that the seam now lines up properly with the fins, so it will be covered by one of the rear fins.
I used the Titebond NRND again, but this time was smart. I applied the glue to the big ring and to the end of the BT80 (which the transition should rest against if I got everything right), but no glue at all to the rear piece of BT55. After I got it into place, I simply filleted that joint to hold it firm.
The only slight trouble spot was the seam, which buckled up from the ring a bit:
I slopped a little more glue in there and squeezed it down. The remaining buckle should (mostly) hidden by the fin that will go on top of it. Remember the gap between the big transition and the fin will be covered by muscle later on.
It is looking very good, and seems to be pretty well supported underneath.
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Put on some muscle today.
I still have a bit of sanding work to smooth out the seams between the pieces (which will never be perfect, but I'll do what I can).
Sanded the Bondo on the big shroud-bt80 joint.
My Bondo sanding skills are grossly deficient. The best I can say is that I think that the seam is on the whole probably slightly better than when I started, maybe. There are some spots where I need a second layer, but I'm really not sure if I'm more likely to make it better or worse, so I'll just quit when I'm... uh, whatever.
I had been toying with the idea of skipping the filler/primer on this model, but screw that, I need all the filling and smoothing help I can get. Sanding it down will be "fun".
I still have a bit of sanding work to smooth out the seams between the pieces (which will never be perfect, but I'll do what I can).
Sanded the Bondo on the big shroud-bt80 joint.
My Bondo sanding skills are grossly deficient. The best I can say is that I think that the seam is on the whole probably slightly better than when I started, maybe. There are some spots where I need a second layer, but I'm really not sure if I'm more likely to make it better or worse, so I'll just quit when I'm... uh, whatever.
I had been toying with the idea of skipping the filler/primer on this model, but screw that, I need all the filling and smoothing help I can get. Sanding it down will be "fun".
grapetang
Space Frog Fan
Motors: D12 and E15
Altitude: not much!
It sims to 300-something on a D12 and 500-something on an E15. Thrust profile of a BP F15 would be ideal to get it up a bit more, but then it'd be seriously tail heavy. 24mm F reloads are likely to be the "best" motor, but I don't do reloads at this time so the disposable E15 will probably be my go-to for this one. It'll maiden on a D12.
Next incarnation? You mean your upcoming build of the APRO Lander 3? Yes please! :wink:
It would be cool to have a fleet of these things, all slightly different, although I don't know when they'd ever be able to get together.
OK on the altitude. My upcoming APRO Lander 3? Ha! It is a nice design and it would be fun adding working landing gear.
If so, the fleet would have both coasts covered and the middle!Roger! Neat design!
Looks great, and people won't notice anyway, especially at 5+ ft.
I haven't tried two-part Bondo but I hear it's easily carved when partially cured (but will gum up sandpaper at this stage); it may be too hard when it's fully cured.Uh, why are the strut frames "muscle"?
'Cuz that's what Gary called it?
Gary Byrum
Overstable By Design
It's no surprise that you had some issues with those 2 shrouds matching up. It's not an easy thing to assemble 2 large paper shrouds together. Mine was less that perfect also.Your 2nd attempt is indeed much cleaner. TOUCHE! Your muscles look very clean also. Much thinner than mine, but they look better. They're just an aesthetic/boo boo hider. Makes for cleaner fillets and gives some strength to the shroud in that weakened area.
As far as I can tell, they're pretty much necessary for both of the those reasons. There are a lot of different variations on how they could be implemented; I considered a few before basically copying your approach. I thought they needed only to be thick enough to fully cover the gaps between the shroud and the fins.
In retrospect there are probably different ways to divide up the muscle into pieces that would have resulted in a cleaner alignment between them (in fact I can think of exactly how I'd do it) but this looks like it should be OK. I really do like the look of how they frame the fins.
Gary Byrum
Overstable By Design
My sloppy fin slots made it necessary to come up with an idea for that. With the fins mounted to the inside, and the muscles on the outside, it seemed it was all the big shroud and fins could ask for. I almost did internal bracing like you did, but I figured the muscles would be support enough. Turns out they are. I have almost no "give" in the big shroud.
That's interesting. I feel like my shroud still has a fair amount of give (though that's subjective), but it's definitely *much* more solid after the muscle was added. I'm glad I put in the bracing, but can't really say for sure that it was *necessary*.
In any event, it's really nice to see the whole thing coming together. The rear fins are the last *visible* thing I need to put in; theoretically I could start painting at that point although I have a couple of last internal items to deal with (motor mount, recovery, and one other that shall go unnamed).
apburner
APBurner
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I read in the first part of this build that you found it hard to find card stock big enough and that you then went with a heavy unspecified paper. I was wondering has anyone tried to us 1/64 plywood for transitions. I should be stiffer and maybe even lighter though more expensive.
Gary Byrum
Overstable By Design
I wonder if some kind of veneer would work? Something flexible enough so you don't have to steam it.
I would probably not be willing to even try it because of the price; with cardstock I can make a bunch and keep throwing them away until I get one that I like but the ply is way too expensive for that.
Technically, I'd be concerned about (a) achieving the necessary bend radius (I haven't work with it before so I really don't know what it's capable of) and (b) maintaining proper curvature at the seam.
All that said, I'd imagine that if you could successfully fabricate the shroud with it then it'd be really good.
After my eventual success with the 65 lb double-layer shrouds, I'd be inclined to try going back to my original posterboard, which in single-layer form was too flimsy, but maybe would work as a double-layer. I may even try to make one just as an experiment. Note this only applies to the big transition, because it won't fit on my normal sheets of cardstock.
I just Googled around a bit and there are actually plenty of 11x17" card stocks available (ranging between 65 and 110 pound, roughly), but they are expensive given how seldom I'd need them, so I'd probably keep trying to extract success out of my cheapo Wally World crap.
OK, here's how I *should* have done the rear fins:
1) Observe that they don't fit well (not surprising really, given opportunity for small errors to accumulate throughout the construction)
2) Cut four brand new fins and sand them until they fit exactly
3) Paper the fins and mount them.
But of course I did not do that. Instead, I did this:
1) Paper the fins when I had some time, long before the rear transition was even installed (so I couldn't really test fit)
2) Observe the poor fit: glue on some shims to enlarge them, and then sand them down to size
3) Glue them in and observe the poor fit yet again
As I posted before, here are the papered parts with extra wood glued on:
I sanded them to fit as well as I could and then glued them in. Aligning them was easy, since they fit between a line on the BT and the outer fin (no jigs or fancy eyeballing necessary), and covering the shroud seam with a fin worked out perfectly. Everything looks great from this angle:
The fit, however, is nothing to write home about (unless to complain, or ask for money):
See what I mean about "should have just cut some new fins"?
I then filled every nook and cranny and crevice with fillet glue, and it certainly looked *better*:
I may need to add some more fillet glue in a few areas where the glue shrank back a bit; we'll see how it looks when it's all finished. Fortunately the rear fins are not so prominently visible, so I can live with the result. But definitely not my finest work, if there is such a thing.
But hey! 5 centering rings, 32 pieces of balsa and basswood, 26 pieces of label paper, and an uncountable number of shrouds later, exterior work is basically finished, and I can preview the completed model:
I honestly wasn't sure if I'd ever get to this point, so I am happy. And this design still looks just as beautiful to me as when I started. It may fly like a brick, but it'll look damned fine on the pad.
I'm now ready to apply primer at the first available opportunity (though who knows when that will be). In the meantime I'll finish the interior work as time permits.
1) Observe that they don't fit well (not surprising really, given opportunity for small errors to accumulate throughout the construction)
2) Cut four brand new fins and sand them until they fit exactly
3) Paper the fins and mount them.
But of course I did not do that. Instead, I did this:
1) Paper the fins when I had some time, long before the rear transition was even installed (so I couldn't really test fit)
2) Observe the poor fit: glue on some shims to enlarge them, and then sand them down to size
3) Glue them in and observe the poor fit yet again
As I posted before, here are the papered parts with extra wood glued on:
I sanded them to fit as well as I could and then glued them in. Aligning them was easy, since they fit between a line on the BT and the outer fin (no jigs or fancy eyeballing necessary), and covering the shroud seam with a fin worked out perfectly. Everything looks great from this angle:
The fit, however, is nothing to write home about (unless to complain, or ask for money):
See what I mean about "should have just cut some new fins"?
I then filled every nook and cranny and crevice with fillet glue, and it certainly looked *better*:
I may need to add some more fillet glue in a few areas where the glue shrank back a bit; we'll see how it looks when it's all finished. Fortunately the rear fins are not so prominently visible, so I can live with the result. But definitely not my finest work, if there is such a thing.
But hey! 5 centering rings, 32 pieces of balsa and basswood, 26 pieces of label paper, and an uncountable number of shrouds later, exterior work is basically finished, and I can preview the completed model:
I honestly wasn't sure if I'd ever get to this point, so I am happy. And this design still looks just as beautiful to me as when I started. It may fly like a brick, but it'll look damned fine on the pad.
I'm now ready to apply primer at the first available opportunity (though who knows when that will be). In the meantime I'll finish the interior work as time permits.
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GlenP
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just get some lightweight spackling compound, or Carpenter's Wood Filler, like for filling body tube seams, that would do the trick to cover up that seam. Or, if you want to continue the glove from the fin above it, add another balsa strip to cover the lower seam and make it match up with the little glove balsa strip above. That might look cool too.
Yeah, and I also have the Bondo although as mentioned previously I don't think I quite have the knack of it yet.
I probably won't try to get it perfect (if at all) until after the primer layer, when I'll be able to see the imperfections a lot better. Right now, particularly with the clear-drying fillet glue, I can't really tell how good or bad things actually are. But a quick layer of CWF in the obvious places might be a smart thing to do at this point.
That might indeed look good but I'm done adding wood to this thing.
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Looking good!
Gary Byrum
Overstable By Design
I honestly wasn't sure if I'd ever get to this point, so I am happy. And this design still looks just as beautiful to me as when I started. It may fly like a brick, but it'll look damned fine on the pad.
GOOOOOO Brick!!! I love this. It's a hoot to see one of my designs take form from someone else. You done gave me the "big head" Neil. I'm gonna think I'm a ROCKet Star!
Glad you like! For this design you deserve a bit of cranial inflation. It's a beauty, and a fun build to boot.
Gary Byrum
Overstable By Design
It's real fun when shi* goes together like you expect it to, huh! When it don't, it might not be so fun, but that creates a challenge. If your rocket build isn't a challenge, then it's skill level 1.
Well, I was at my bench working on something else, so I figured while I'm there to try a little CWF, using a slightly thicker mixture than I use to spiral filling. It worked great:
I shouldn't be surprised since that's basically a perfect use for the stuff. While at it I also filled the gap where the front of the main fins meets the muscle:
Hard to tell in the pictures but it all came out good. *Now* it's ready for primer.
Thanks GlenP for the prodding!
I shouldn't be surprised since that's basically a perfect use for the stuff. While at it I also filled the gap where the front of the main fins meets the muscle:
Hard to tell in the pictures but it all came out good. *Now* it's ready for primer.
Thanks GlenP for the prodding!
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Gary Byrum
Overstable By Design
Well whaddaya know, using filler putty for filler putty purposes. Who'd have thunk?
I know, right? I'll add it to the list of "surprising things I learned during this build".
Nytrunner
Pop lugs, not drugs
What do you use as "fillet glue"?
I tried to search, but couldn't find it specified.
(also, when this one's done, does the Avalon come next?)
I tried to search, but couldn't find it specified.
(also, when this one's done, does the Avalon come next?)
GlenP
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Glad to help you see the forest through the trees. I use that wood filler on furniture projects all the time, and it comes in handy on rockets too. Your custom scratch builds and artwork in Open Rocket and face cards are inspiring. I usually just start building or kit bashing without a real plan and sort of see what evolves, one of these days I might try to sketch out a plan first.
Titebond No Run No Drip. I'm tired of writing that, so I'm just gonna say "fillet glue" from now on.
That's the plan. Gotta get the parts for that one ASAP.
Nytrunner
Pop lugs, not drugs
Thanks! Is the NRND similar to the Molding and Trim? And is it different from the Quick & Thick multi-surface?
Wood glue is new for my rockets, so I'm trying to figure out which works for what applications.
Wood glue is new for my rockets, so I'm trying to figure out which works for what applications.
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