In a sane world I'd be there with bells on! But...
Biohazard build thread
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In a sane world I'd be there with bells on! But...
Future drip-drying in the garbage can...
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Future is dry, looks good but no pic right now because really it's just about the same as before. Eventually I'll take some beauty pics outside.
Down to the end game: Tying the shock cord and installing the nose retainer. The former is pretty boring, so let's talk about the latter.
Because this all seemed to go pretty well in the Diamond Cutter build, I decided to do it again here pretty much the same way, except here I've got a BT50 to work with instead of a BT60, so things are tighter. As before, the objective is to have a good way to secure the nose cone without having to make it extremely tight, while also being easily removable so I can shove an altimeter in there eventually. In fact, with the thin-walled BT50 in the payload section of this rocket, this is even more important because it is *so easy* to mess up a BT50 while grabbing it and trying to pull out a tight nose cone (don't ask me how I know this.
) So I really want the nose cone to be reasonably loose but secure.
The retainer is simply a smaller-diameter version of the BT60 design. Unfortunately, the quality of print I got this time was not great, and I had to do a lot of sanding to get the fit to be just-tight-enough-without-being-too-tight. Eventually I achieved satisfactory results, although I believe the design can be improved to reduce the chance of the problems I experienced here. But that's for the next rocket.
Anyway, here are the two pieces:
On the left is the nose cone piece, and on the right is the piece that inserts into the BT. Orientation is upside down, this is essentially looking up to the nose cone from below. Here are the two pieces locked together:
Installing these guys is a two-stage procedure. First I must glue the nose cone piece to the nose cone. There are two things of paramount importance here: (1) positioning the piece correctly, and (2) not accidentally gluing together the wrong things. The design of the retainer is actually intended to help with #2, but #1 is all about the process.
With the two pieces locked together, I inserted them partway into a piece of scrap BT50, like so:
Next I dolloped a bit of 30-minute epoxy onto the back of the NC piece:
Then I stuck the nose cone onto the glue. With 30-minute epoxy I have plenty of time to work, so initially I'm just looking to get the balsa set into the glue nicely, in *approximately* the correct position:
Finally, I push the entire assembly gently into the tube. Initially I only did it partway, just enough to ensure good alignment of everything:
Later I decided that there was no real reason not to push it in all the way, so I did. Here's a peak in from the other end; with everything looking good:
The BT piece is a fairly snug fit, so once the nose cone is pushed in nothing is going to move on its own. Now I let it sit for a day, and then I'll pull out the nose cone, and if all goes well everything else will come out with it (remember the BT piece is not glued in at this point, but it is locked to the NC piece).
A couple of notes:
1) for this process I mixed an almost ridiculously small batch of epoxy, and because I didn't have anything good on hand to mix it with, I used a Q-tip. The Q-tip did a fine job mixing it, but it also absorbed almost 100% of the epoxy. On my second try I used a long screw. I will have to find my wooden craft toothpicks that I normally use for this.
2) The retainer pieces were printed in ABS, which I know is troublesome to glue. I'm hoping that the 30 minute epoxy does the trick; fortunately this joint is not going to be particularly stressed, so I hope it'll be OK. If it were to let go, it wouldn't be a tragedy anyway.
Down to the end game: Tying the shock cord and installing the nose retainer. The former is pretty boring, so let's talk about the latter.
Because this all seemed to go pretty well in the Diamond Cutter build, I decided to do it again here pretty much the same way, except here I've got a BT50 to work with instead of a BT60, so things are tighter. As before, the objective is to have a good way to secure the nose cone without having to make it extremely tight, while also being easily removable so I can shove an altimeter in there eventually. In fact, with the thin-walled BT50 in the payload section of this rocket, this is even more important because it is *so easy* to mess up a BT50 while grabbing it and trying to pull out a tight nose cone (don't ask me how I know this.
) So I really want the nose cone to be reasonably loose but secure.The retainer is simply a smaller-diameter version of the BT60 design. Unfortunately, the quality of print I got this time was not great, and I had to do a lot of sanding to get the fit to be just-tight-enough-without-being-too-tight. Eventually I achieved satisfactory results, although I believe the design can be improved to reduce the chance of the problems I experienced here. But that's for the next rocket.
Anyway, here are the two pieces:
On the left is the nose cone piece, and on the right is the piece that inserts into the BT. Orientation is upside down, this is essentially looking up to the nose cone from below. Here are the two pieces locked together:
Installing these guys is a two-stage procedure. First I must glue the nose cone piece to the nose cone. There are two things of paramount importance here: (1) positioning the piece correctly, and (2) not accidentally gluing together the wrong things. The design of the retainer is actually intended to help with #2, but #1 is all about the process.
With the two pieces locked together, I inserted them partway into a piece of scrap BT50, like so:
Next I dolloped a bit of 30-minute epoxy onto the back of the NC piece:
Then I stuck the nose cone onto the glue. With 30-minute epoxy I have plenty of time to work, so initially I'm just looking to get the balsa set into the glue nicely, in *approximately* the correct position:
Finally, I push the entire assembly gently into the tube. Initially I only did it partway, just enough to ensure good alignment of everything:
Later I decided that there was no real reason not to push it in all the way, so I did. Here's a peak in from the other end; with everything looking good:
The BT piece is a fairly snug fit, so once the nose cone is pushed in nothing is going to move on its own. Now I let it sit for a day, and then I'll pull out the nose cone, and if all goes well everything else will come out with it (remember the BT piece is not glued in at this point, but it is locked to the NC piece).
A couple of notes:
1) for this process I mixed an almost ridiculously small batch of epoxy, and because I didn't have anything good on hand to mix it with, I used a Q-tip. The Q-tip did a fine job mixing it, but it also absorbed almost 100% of the epoxy. On my second try I used a long screw. I will have to find my wooden craft toothpicks that I normally use for this.
2) The retainer pieces were printed in ABS, which I know is troublesome to glue. I'm hoping that the 30 minute epoxy does the trick; fortunately this joint is not going to be particularly stressed, so I hope it'll be OK. If it were to let go, it wouldn't be a tragedy anyway.
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OK, here's the first piece of good news:
So the whole thing wasn't glued into the scrap tube. Next:
So the two pieces weren't inadvertently glued to each other. And the NC piece is stuck to the nose cone as intended. Success!
Next step (gluing in the BT piece) waits a few days for an opportunity.
So the whole thing wasn't glued into the scrap tube. Next:
So the two pieces weren't inadvertently glued to each other. And the NC piece is stuck to the nose cone as intended. Success!
Next step (gluing in the BT piece) waits a few days for an opportunity.
Next the BT part of the retainer gets glued in. This requires care, because ultimately the joint is made blindly.
After re-attaching the two pieces together, I measured and marked my glue stick... er, make that "glue bolt". The idea is to apply the glue deep enough into the BT to just adhere the glue tabs which stick out the bottom.
Next I apply two dollops of glue at that depth on opposite sides of the tube. I insert the nose cone with the tabs 90 degrees away from the glue. Then, when the nose is fully inserted, I twist 90 degrees (a bit more, actually) to engage the tabs with the glue, and then set down to cure.
After re-attaching the two pieces together, I measured and marked my glue stick... er, make that "glue bolt". The idea is to apply the glue deep enough into the BT to just adhere the glue tabs which stick out the bottom.
Next I apply two dollops of glue at that depth on opposite sides of the tube. I insert the nose cone with the tabs 90 degrees away from the glue. Then, when the nose is fully inserted, I twist 90 degrees (a bit more, actually) to engage the tabs with the glue, and then set down to cure.
Aaaaaand it's done. The nose cone twisted and came out easily, revealing the lock inside the BT:
Neato.
I also made a nearly useless video showing it in action:
Neato.
I also made a nearly useless video showing it in action:
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Gary Byrum
Overstable By Design
And I take it, your altimeter will fit through that small opening in the lock rig?
A JL Altimeter should fit in there, unless I measured wrong. :eyepop: This BT50 is probably the smallest practical size for this; the BT-60 version was much easier to work with.
Cabernut said:
It's extremely comfortable at BT-60, and I presume it could scale up as much as needed, although the design would need to be adjusted. I'd love to see someone try something comparable at a larger size.
Finally got around to hooking up an overly-long shock cord (I'm probably going to shorten it a bit) and the parachute, and final weight comes out around 2.9 oz, not *too* much over the sim weight of 2.66 oz. The added weight seems to be mostly in the rear, though, so CG has moved back about 1.3". Fortunately this design has plenty of margin, so no problem, but I'll need to adjust my sims in the future to account for fin papering which I believe is the biggest source of added weight.
She's theoretically ready to fly now, although as I said I think I'm going to shorten the shock cord a bit; it looked like a bit much packed into the lower BT55.
She's theoretically ready to fly now, although as I said I think I'm going to shorten the shock cord a bit; it looked like a bit much packed into the lower BT55.
Biohazard flew twice at BARC yesterday.
First time was on a C11-3, absolutely arrow straight with no rotation, I was very pleased (probably the straightest flight of any rocket I've ever launched). Recovery on the 15" Odd'l chute with a nice spill hole was perfect. Altitude was better than I expected with the C11, I would not hesitate to fly it on those in the future.
Faced with a gigantic flat recovery area at Rabbit Hill Farm, I got ambitious with the second flight and stuck in a D12-5. That went really quite high, and then drifted... really quite a long way. I was ready to give up on it but a local club member named Jeremy (if you're out there dude I really do owe you one) eventually found it way beyond where I thought it could possibly have gone. I feel very fortunate to have gotten it back.
But overall it flies fantastically.
Here's the only launch pic I have so far:
First time was on a C11-3, absolutely arrow straight with no rotation, I was very pleased (probably the straightest flight of any rocket I've ever launched). Recovery on the 15" Odd'l chute with a nice spill hole was perfect. Altitude was better than I expected with the C11, I would not hesitate to fly it on those in the future.
Faced with a gigantic flat recovery area at Rabbit Hill Farm, I got ambitious with the second flight and stuck in a D12-5. That went really quite high, and then drifted... really quite a long way. I was ready to give up on it but a local club member named Jeremy (if you're out there dude I really do owe you one) eventually found it way beyond where I thought it could possibly have gone. I feel very fortunate to have gotten it back.
But overall it flies fantastically.
Here's the only launch pic I have so far:
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Cabernut
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Good to see it fly. Just this last weekend, I had an Air Commander that drifted farther than it went up, and that's with low winds. Almost gave up looking when I saw a glint of something in a bean field. Sometimes you never know when a thermal will decide to play with your rocket a while.
I was extremely frustrated because I was walking towards it as it was coming down, keeping my eyes on it, and then I simply had to look down for *a second* to relax my neck and then when I look up again I couldn't find it. In the future I think I will watch while standing still, and only start walking after it's down. Too hard to walk continuously while looking up. Although I've done that in the past, and have always been able to pick it up again after momentarily looking down.
I knew the wind was picking up as the day was going on; this flight convinced me not to put anything else up high for the day, which prevented me from getting another flight in on the Diamond Cutter.
Thread necro!
Some time back it was asked if my hypothetical altimeter would actually fit through my twist-lock ring inside the payload section. Here's the answer:
Just nabbed an Altimeter 3, and first thing to try was putting it in there. It went in but hung up just a tiny bit on the points sticking out of the locking flanges. I filed them down just a tiny bit to take the points off, and now the Alt3 slides in very cleanly. Success, if just barely.
Now I gotta drill some holes...
Some time back it was asked if my hypothetical altimeter would actually fit through my twist-lock ring inside the payload section. Here's the answer:
Just nabbed an Altimeter 3, and first thing to try was putting it in there. It went in but hung up just a tiny bit on the points sticking out of the locking flanges. I filed them down just a tiny bit to take the points off, and now the Alt3 slides in very cleanly. Success, if just barely.
Now I gotta drill some holes...
Scotty Dog
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I remember this build..cool it flew. I almost lost my Fliskit Rock Star "Purple Haze" at a CMASS launch . The thing has so much fin area , it just drifts and drifts even in a little breeze. I found it WAY out in the swamp. I spent most of the afternoon looking for it. I did not want to drive home (almost 2 1/2 hrs) without it. Even tho I found it, it was a bummer cuz I didn't get to fly but a couple because of the time spent looking.
Very nice, just seeing this thread for the first time, beautiful rocket! It'd be nice to see more launch photos or videos.
Thanks. Unfortunately I don't have anything else to show at the moment; I've been trying to watch my launches with my eyes, and there hasn't really been anyone else with me able to take good launch pics or video.
I will be flying this one again with my new Alt3, so hopefully I can get some decent shots of that one.
