And BAM! just like that, nose cone question...

Ok, as I prepare to scratch build my first rocket in, oh, 9 years or so, I wonder if anyone can answer a question for me. I use non-standard body tubes (read: any tube I can find that happens to catch my fancy), so naturally, there is a dearth of nose cones out there that will fit my builds. I usually make due with jerry-rigging Estes nose cones, but this new project will be bigger than any nose cone I have, so that's right out. Nor do I have a lathe for turning a nose cone that will fit my project (though I'm currently exploring options for building a lathe, since I can't afford to buy one). What I DO have, however, is a nice, big block of balsa wood, a saw, and some model files and rasps that would be perfect for shaping that block of balsa. So, here's my question: does ANYONE know how to mark out stations on the wood to get the profile of the nose cone right? The last thing I want is to cut into the wood only to produce a lop-sided or crooked nose cone. I have to work it by hand, so I could really use any suggestions anyone might have. Thanks!

How big? I've done up to about 2.25" balsa on a hand drill. I like to glue a section of brass tubing into a big block as I have broken more than one dowel. Not saying my technique is great. To get the shoulder right, I slip a short piece of tube over the end of the drill to check as I get close. As for a profile, you can sketch out a negative profile of half the cone to hold up and eyeball as it is shaped.

Now the experts can chime in...

75mm (~3 in) interior diameter. I have NO power tools to work with, though. This all has to be done the old fashioned way. That's why I was hoping someone had some experience lofting and marking stations like they do when building boats, so I could learn how to get the curves right. I want this thing to look ​smooth.

Can't help you there...Harbor Freight has some pretty inexpensive drills...

you could go with paper!! a series of transition cones glued together would approximate an ogive... the technique is outlined here https://www.rocketryforum.com/showthread.php?120758-Nose-Cone-Needed&p=1404351#post1404351 I made a BT-80 "V-2-like" model (nose and boat tail). It is surprisingly strong, no lathes required.

other discussions here https://www.rocketryforum.com/showthread.php?26305-Paper-Ogive-Nose-cone

Why not try Hobby Lobby and the foam cones they have?You might find something close and go from there.

If you want to make a large (75mm counts as far as I'm concerned) nose cone without power tools, you might want to take a look at issue 87 of Apogee's Peak of Flight newsletter:

https://www.apogeerockets.com/education/downloads/Newsletter87.pdf

The method involves busting up a foam block from pieces of blue or pink foam (not beaded or open cell foam), attaching it to a turntable, and mounting a silhouette of the cone on the side. You then use a hot wire cutter along the silhouette to cut out the nose cone profile. Rotate the turntable, and repeat. Depending on how small the rotations are, you should get a pretty nice nose cone. Just sand and glass.after glassing, you can even dissolve the foam core out with acetone if you like, are leave it there for strength. I'm thinking this is your best bet if you want to make it yourself without turning it.

I hadn't thought to mention the general technique that Greg mentioned. I wonder if you could try something similar with the balsa. Instead of a hot wire use a saw (hacksaw?) that could rest across the silhouettes. I looked at Tim Van Milligan's book and he covers the foam technique. He also mentions you can form a cone with hand tools, but doesn't provide any great tips. I still say a $20 drill from HF is the way to go. It would make a nice symmetric cone and would have many non-rocketry uses. Sorry to be a broken record...

Thanks for the suggestions, y'all. I'm exploring each one of them, and seeing which one would work for me. It might turn out that a combination of techniques would be most effective. Keep 'em coming!

I gotta say, one thing I love about this hobby is the way it gets you looking at everything in your house and all around you with new eyes. I just realized that I have a bunch of empty plastic bottles which are the perfect size for payload bays, for starters. And to the topic of this thread, I just remembered that I have a big bag of sawdust that I got for free at Home Depot, and I have plenty of wood glue. I'm thinking I might be able to form a rough shape out of wood paste, then sand and file it into final shape when it's dry. I'm going to a small-scale test of this tonight. I'll let y'all know the results as it's finished.

Go for it. Let us know...include photos!

Ok, so the test of the "wood filler nose cone" was an unmitigated disaster. I wasn't exactly confident of the results to begin with, but it turned out worse than I thought it would have. I took no pictures; I figured I'd spare y'all the sight of that train wreck. It was truly awful.

However.

I started work on a new technique today, and, though it might not turn out perfect, I'm VERY encouraged by the results so far. If all goes well, I should end up with a light, strong nose cone that doesn't look all that bad, either. I'm documenting what I'm doing with images, so, when I've made a little more progress, I'll start putting them up for y'all to see. I'll probably just start another thread on it, and post a link to it in here, because I'd rather not turn a question thread into a build thread. The technique, though, is pretty easy; I just need to figure out a way to make it more accurate. Anyway, back to work.

Here's the link to the new build thread:

https://www.rocketryforum.com/showt...-(I-think)-build-thread&p=1479877#post1479877

No pics yet. Not sure why, but it won't let me post any. I'll put some up as soon as I can figure it out.

The traditional boatbuilding lofting approach is to divide into sections and work from there. I see this as having two approaches for your application. The first would be to get a series of balsa rounds of progressively smaller diameter (3", 2.5", 2",...), and glue them into a wedding cake. The length of each diameter would be carefully calibrated to give you the right shape when you've removed the corners. The smaller diameter at each step should be where you want the edge of the nose cone to be. It's pretty easy to shape it down slowly so you don't go past the line. The tricky part is getting all of the diameters straight and on the same line.

If you already have a block of balsa to work from, you might get a template of the nose cone profile then draw it on three sides. With some careful cutting, you can get a cone that has the right profile at 0, 90, and 180 degrees. You can then shape down from there doing your best to maintain symmetry and roundness. Regular checking with the body tube will be a must in the final stages at the shoulder.

There is a thread on YORF where a guy built his own nose cone out of balsa.

https://www.oldrocketforum.com/showthread.php?t=5843&page=1&pp=10

Greg

PS: If you have a system at work that screens websites, you may not be able to see the pictures. I think it is a very interesting thread, since he hits on various methods of scratch building.

Besides the Apogee newsletter mentioned above, Tim has a special report on DVD that shows how to make nose cones without power tools. I have it, and it's excellent.

I'll second using paper (thick cardstock).

How about finding the nosecone shape you want in profile (ex. a pic or even Rocksim), enlarge to the size you need, print out 4 times, cut and paste to the sides of the block of wood? You can then carve and also use hole templates to ensure it is concentric at different points.

Ex. nosecone profile pic found on Rocket Reviews (Aerotech Ogive 4137):
https://www.rocketreviews.com/aerotech-ogive-nose-cone-4137.html


I remember having some old wood carving kits and they often would just print the image on the sides of the block, so this is a variation of that.

KenECoyote said:

How about finding the nosecone shape you want in profile (ex. a pic or even Rocksim), enlarge to the size you need, print out 4 times, cut and paste to the sides of the block of wood? You can then carve and also use hole templates to ensure it is concentric at different points.

Ex. nosecone profile pic found on Rocket Reviews (Aerotech Ogive 4137):
https://www.rocketreviews.com/aerotech-ogive-nose-cone-4137.html

I remember having some old wood carving kits and they often would just print the image on the sides of the block, so this is a variation of that.

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Excellent idea! Can you elaborate on the use of the hole templates you mentioned?

stormhawk31 said:

Excellent idea! Can you elaborate on the use of the hole templates you mentioned?

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Thanks! The hole templates are just something I thought of as I was typing...the trick for you is to make sure the carving is round since you're not using a lathe/power tool. Given that, just eyeballing alone can lead to a lot of inaccuracy and hole templates allow you to check how much off-round you are. I'm saying to just use maybe a piece of cardboard with circles of different sizes cut out of it (something like 4 sample diameters throughout the cross section) - if your biggest diameter is 4", make 1", 2", 3", 4" cut holes...each on a different piece of cardboard). Then as you're carving, every once in a while use the cardboard with 1" hole in it and slip it over the front to see how round your carving is, then 2", etc. This can ensure it is round since otherwise you're only checking the profile against two side reference points.

Just brainstorming here and haven't actually done this myself, but it is what I would try in this case.

Also with this method it would probably make the most sense to first saw off near the outlines, then fine saw/carve the edges, then fine carve/sand round.

Also just as a general service reminder to everyone (never know who is reading this), anytime you're using knives, especially when carving, always have the path of the stroke away from you. The idea is you never want any part of your body in front of the blade in case it slips or suddenly moves forward. I grew up wanting to try surviving in the woods with just a knife and the #1 rule is don't cut yourself (or others) and I try to use that same mantra when using knives in general. Stay safe!

Jeffmhopkins said:

I'll second using paper (thick cardstock).
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OOOH, that's purty!