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My Balsa Machining Service order.

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Senior Space Cadet

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I got an assortment of nosecones, transitions, and boat tails from Balsa Machining yesterday.
Tomorrow is my rest day, no hikes or bike rides, so I may get a chance to lay out some interesting combinations and take photos for the forum.
In the meantime, here is a screenshot of a quick design I did, using one of the nosecones and boat tails. And, yes, I have the fins on the boat tail, which I think is appropriate.
It is a 41.6 (BT-60) rocket. Looks very much like a smaller version of a BT-80 I did, except the BT-80 didn't have a boat tail. Apogee isn't much. I used a C6-7 in the design, which is pretty small for such a big rocket. With this boat tail, I could use a D motor, and probably would.
I have a similar boat tail that will take 24mm motors, so I could go considerably larger. With an E motor, it would probably go pretty high.
Screenshot 2020-10-08 06.50.09.png
 

dr wogz

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moving the fins up & onto the body tube can make assembly easier. it only move the CP a bit, requiring maybe a bit of nose weight or a longer body tube..
 

teepot

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I get a bunch of stuff from Balsa Machining too. His prices are much lower than everyone else. And he is 5 minutes from my house.
 

prfesser

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I've ordered from Balsa Machining periodically over the last 20 years. Always great products, very reasonable prices, and great service. The only thing I find disappointing is that they no longer offer "semi-custom" nose cones, tail cones, adapters, etc. You'd select a general shape from their list, input some dimensions, and a week or so later your customized nose cone or adapter arrived in the mail. Great for oddball sizes of tubing such as mailing tubes, and for scale modeling.

Bill ought to post some pictures of his lathes/other machines in operation.

Best -- Terry
 

teepot

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I've ordered from Balsa Machining periodically over the last 20 years. Always great products, very reasonable prices, and great service. The only thing I find disappointing is that they no longer offer "semi-custom" nose cones, tail cones, adapters, etc. You'd select a general shape from their list, input some dimensions, and a week or so later your customized nose cone or adapter arrived in the mail. Great for oddball sizes of tubing such as mailing tubes, and for scale modeling.

Bill ought to post some pictures of his lathes/other machines in operation.

Best -- Terry
I'll let him know. I see him almost every week.
 

jqavins

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I've ordered from Balsa Machining periodically over the last 20 years. Always great products, very reasonable prices, and great service. The only thing I find disappointing is that they no longer offer "semi-custom" nose cones, tail cones, adapters, etc. You'd select a general shape from their list, input some dimensions, and a week or so later your customized nose cone or adapter arrived in the mail. Great for oddball sizes of tubing such as mailing tubes, and for scale modeling.
I was disappointed by that loss as well, but on the other hand I had mixed results when using that service. I got some special centering rings that came out great. I wanted to order a nose cone with the shoulder dimension being zero, and a transition with the forward shoulder zero (to glue together into my own compound nose shape) and the order form wouldn't allow that. Another time I ordered a nose cone with all the parameters within the order form's constraints; he couldn't make it and instead of telling me he took a guess and made something else. Yes, he refunded my money, but that's not really the point.

Despite that though, I repeat, it is a loss. I'm sure I would have used that service more than a few times since then if I could have.
 

Senior Space Cadet

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When I placed my order, with Balsa Machining, I tried to order a wide assortment of transitions and a few nose cones, without much regard for how they'd work together. That was a mistake. Transitions, generally speaking, need to be paired with a nosecone or another transition. A transition by it's self isn't very useful.
Also, a transition from, say, BT-55 to BT-50 is useful, but a transition that goes from BT-60 to BT-20 is not.
So I placed yet another order with Balsa Machining, and an order with Apogee.
Some of the combinations I have in mind involve cutting off the shoulders of two of the components and gluing them directly together. That will probably work better with a nosecone and transition, rather than two transitions. If I don't make the cut perfectly, I could get misaligned tubes.
I found a longer version of the BT-60 Big Bertha nose cone. And I ordered some elliptical fins from Apogee. Here is a nearly finished design using them. Not a lot different from the one above. In the actual build, the fins will be swept back slightly.
 

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Senior Space Cadet

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I like working in BT-50 (24mm). The only part about BT-50 I don't like is there isn't a lot of room for a chute, shock chord and altimeter. BT-55 is much easier to work with, in that regard.
What I need to find out, using Open Rocket, is will a BT-55 that transitions down to a BT-50 result in better performance than a BT-55 that stays BT-55 till the tailcone? That is, does it make sense to have a BT-55 rocket up front, so there is more room, then transition down to BT-50 for the back half?
 

dhbarr

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I like working in BT-50 (24mm). The only part about BT-50 I don't like is there isn't a lot of room for a chute, shock chord and altimeter. BT-55 is much easier to work with, in that regard.
What I need to find out, using Open Rocket, is will a BT-55 that transitions down to a BT-50 result in better performance than a BT-55 that stays BT-55 till the tailcone? That is, does it make sense to have a BT-55 rocket up front, so there is more room, then transition down to BT-50 for the back half?
All other things being equal, sure -- consider a downscale Ventris, for instance.
 

jqavins

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What DH said, with one caveat: it'll help, but it won't help much. It looks good and makes only a little difference to performance. And there's plenty to be said for good looks.
 

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I'm still waiting on the longer elliptical nosecone, but I went ahead and started construction. I'd probably start paint tomorrow, if I had the right nosecone.
Here it is with the shorter nosecone. Fins are pretty big. I used precut fins from Apogee. Should perform well. The Screen shot is of what may be my next rocket. I should do a closeup of the fillet to show that I have, indeed, "opened the book".

BT-60, Renegade nearing completion.jpg
Screenshot 2020-10-12 04.24.48.png
 

Senior Space Cadet

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I did a mock-up to show what you can do with transitions and nosecones from Balsa Machining. There is no logic to the tube lengths, I just used scraps I had from previous builds.
Something that hadn't really occurred to me before is that, if you actually intend to launch the rocket and not just put on display, the lack of holes in the transitions creates serious problems. For a design like this, you'd need a drill press to make holes in the transitions, or you'd have to use rear eject, of which a lot of you seem to have a low opinion. I don't have any experience with it, so I have no opinion yet.
I don't have a drill press and I make rockets to launch, so I need to do some serious thinking about how I could use these parts in a practical way.
I'm running out of room for rockets. I think I'm going to take a break from building till they allow launchings again.

BM mockup.jpg
 

jqavins

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One option is to make the lowest tube long enough to hold the recovery system, then separate there such that all the size changing features constitute a single subassembly.
 

teepot

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Bill, of Balsa Machining, told me how to drill the balsa transitions. You need a sharp bit and high speed. Worked fine.
 

jqavins

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Without a press? How did you hold the part and drill and get everything steady and lined up? (With a drill press it's be easy.)
 

XrayLizard

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Easy peasy
Dremel tool , use a burr to create a hole the size + of a sanding drum bit
Use sanding drum bit to finish it out
No need for perfection.
Dremel advantage is the high speed and you just peck away. Unlikely to grab, like a drill press would.
On the press start with small diameter and work your way up
 

XrayLizard

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Besides a small drill press can be found good used for very little moolah. Maybe a neighbor has one to use! Six pack can go a long ways lol
 

PhlAsh

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Has BMS actually resumed Balsa Machining?
 

kuririn

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Make your transitions out of cardstock.
No drilling needed.
No balsa parts to buy.
Cheap.
 

prfesser

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Make your transitions out of cardstock.
No drilling needed.
No balsa parts to buy.
Cheap.
And if you layer four or five cardstock transitions w/epoxy, they work nicely for mid-power and even some high power. Top with fiberglass and they'll handle an M motor---my L3 was an example.
 

afadeev

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One more order for BMS coming up.
I place 1-4 orders with Bill of BMS every year.
Perfect outcomes every time.

Hoping he will stay in business for as long as I have interest in this hobby!
 

Gus

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Bill stopped doing custom nosecones because he "semi-retired." It was just too much work for someone trying to cut back. He is still an absolute treasure for our hobby.

If you need a special one-off nosecone or transition Gordy of http://www.sandmandecals.com is still doing custom work. He just completed an absolutely perfect scale 13" x 3.1" nosecone of a Russian hail-abatement rocket for me.

One more note about Bill. Every year Bill donates a big bag or two of "reject" cones and transitions to the auction at NARAM. They usually go for upwards of $100 each. Bill's been doing this for years and has raised a huge amount for the Cannon Educational Fund. Just a great guy in so many ways!
 
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