Just curious, how do you determine the curve?
Eyeball, or is there some tool or technique?
The detail is incredible.
LOC 4" Nike Zeus build thread (With mods)...
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Eyeball, or is there some tool or technique?
The detail is incredible.
Yes, I'd like to know as well.
Thanks buddy...
I know a few ways to determine the curve of a part like that. One is to use something like this:
But with a compound curve and an angle it is pretty awkward to get right and might be more frustrating than just starting with a guess in the first place.
The way I did it in this case involves a tiny bit of artistic ability, but only a tiny bit.
The trick is to hold a piece of wood in place at the correct angle under direct light, then draw the shape of the cast shadow onto the piece. I'll see if I can get a picture of the concept...
Okay, I made up a little demo piece and I think it'll get the idea across...
In this pic the bulkhead piece is to the right and the tip of the nosecone to the left. The shadow we're looking at is the one cast onto the nosecone. Rotate the nosecone (or whatever it is) until the shadow corresponds to the base of the bulkhead.
Now draw the shape of the shadow on to the wood piece with a pencil.
Then just cut along the line. It'll need a little sanding to be perfect, but just a little bit. Once you get the first piece right, just use it as a template to cut out the rest.
This works pretty well for me. On bigger parts you can use a flashlight or something to line up the light source rather than trying to get the part oriented to the light.
Anyway, I hope that was a usable explanation...
Absolutely.
Good tip, thanks.
Did a bit of detail stuff on the "missile control unit". Primarily because I had had enough of filling spirals and needed to do something else. Still need to fill the spirals on the payload tube.
As I have said many times before, this is not an accurate scale model, just going for the look. That means I get to be a bit creative with the fiddly bits. I wanted to simulate the pivot points for the canards, even though on the real Spartan the pivots are not this visible. I also added some little vent looking things in a couple of places.
I made the "pivots" from balsa. I started by cutting out four discs that were a little bigger than the thickness of the fin, then cut out that thickness from the middle of the disc.
The little side pieces were glued to either side of the fins.
Then I made a little sanding block and sanded them so that the pivot surface is perpendicular to the fin.
They'll get a little fillet just to smooth out the edges. Here's what it looks like with the node cone in place. I'm pretty happy with the way things are looking so far! I'm planning on scribing some panel lines into the nose cone to look like a nose cap and a few access panels...
Looks like some of those were taken before I sanded the discs.
I guess I'm going to have to go back to filling spirals now...
More later, thanks for looking!
As I have said many times before, this is not an accurate scale model, just going for the look. That means I get to be a bit creative with the fiddly bits. I wanted to simulate the pivot points for the canards, even though on the real Spartan the pivots are not this visible. I also added some little vent looking things in a couple of places.
I made the "pivots" from balsa. I started by cutting out four discs that were a little bigger than the thickness of the fin, then cut out that thickness from the middle of the disc.
The little side pieces were glued to either side of the fins.
Then I made a little sanding block and sanded them so that the pivot surface is perpendicular to the fin.
They'll get a little fillet just to smooth out the edges. Here's what it looks like with the node cone in place. I'm pretty happy with the way things are looking so far! I'm planning on scribing some panel lines into the nose cone to look like a nose cap and a few access panels...
Looks like some of those were taken before I sanded the discs.
I guess I'm going to have to go back to filling spirals now...
More later, thanks for looking!
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Been doing a lot of tedious sanding lately, so while there has been progress very little of it was worth posting. Everything looks pretty much the same, just smoother....
I did get a little bit more detail stuff done last night. It doesn't look like much, but it took me a while to figure out how I wanted to go about it.
The Spartan had a series of holes around the top of the booster interstage connector. (Vents for gap staging, I always figgered...
) I wanted to do a 1/64" ply wrap with holes in it to simulate the interstage, but wasn't sure how to go about cutting all those holes in the thin material. Laziness dictated that a circle template and hobby knife were out of the question, and extensive searches revealed that small, accurate circle cutters only seemed to be available at great expense. After a few weeks of searching, Michael's actually had the answer...
This thing:
Its a 3/4" lever punch. I wasn't sure if it would punch holes in plywood, but for about ten bucks (And many other uses besides this project) I decided to give it a try. Turns out it handled the thin ply with little effort.
The wrap was made in four pieces because it was going between the balsa strips I glued into the original middle fin slots.
Each was then sanded to fit between the strips and glued to the tube.
Next will be some 1/8 - 3/16 wide strips glued alongside the balsa pieces to give the impression that they are hat-section reinforcements welded to the booster to add strength to the interstage. Then a much easier to make wrap, just above this one, that will look like the clamp that holds the stages together.
Oh, and more sanding...
Thanks for checking in!
Mike
I did get a little bit more detail stuff done last night. It doesn't look like much, but it took me a while to figure out how I wanted to go about it.
The Spartan had a series of holes around the top of the booster interstage connector. (Vents for gap staging, I always figgered...
) I wanted to do a 1/64" ply wrap with holes in it to simulate the interstage, but wasn't sure how to go about cutting all those holes in the thin material. Laziness dictated that a circle template and hobby knife were out of the question, and extensive searches revealed that small, accurate circle cutters only seemed to be available at great expense. After a few weeks of searching, Michael's actually had the answer...This thing:
Its a 3/4" lever punch. I wasn't sure if it would punch holes in plywood, but for about ten bucks (And many other uses besides this project) I decided to give it a try. Turns out it handled the thin ply with little effort.
The wrap was made in four pieces because it was going between the balsa strips I glued into the original middle fin slots.
Each was then sanded to fit between the strips and glued to the tube.
Next will be some 1/8 - 3/16 wide strips glued alongside the balsa pieces to give the impression that they are hat-section reinforcements welded to the booster to add strength to the interstage. Then a much easier to make wrap, just above this one, that will look like the clamp that holds the stages together.
Oh, and more sanding...
Thanks for checking in!
Mike
How on earth did I miss the build until now... just read through the whole thing, fantastic work. I could not get tired of seeing you build up fins like that.
I especially love that this whole thing is being done with wood and paper. Bravo sir!
I especially love that this whole thing is being done with wood and paper. Bravo sir!
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Mike,
I wish I had a fraction of your modeling skill. I think this thread your doing is very inspirational.
I am going to work hard on my current LVL 2 MODEL to get a nice finish !!
I wish I had a fraction of your modeling skill. I think this thread your doing is very inspirational.
I am going to work hard on my current LVL 2 MODEL to get a nice finish !!
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^^^^^^^this!^^^^^^^
Y'all are gonna make me have to buy a bigger hat if you keep talkin' like that... 
Seriously though, you guys are so kind, and coming from you folks, high praise indeed!
Oh, and by the way Paul, I've been following your level 2 build and I don't see any lack of modelling skills there at all! We all have different ways of doing things and that is what makes this place so much fun, we get to see how other folks do things and try 'em ourselves.
Seriously though, you guys are so kind, and coming from you folks, high praise indeed!
Oh, and by the way Paul, I've been following your level 2 build and I don't see any lack of modelling skills there at all! We all have different ways of doing things and that is what makes this place so much fun, we get to see how other folks do things and try 'em ourselves.
Thanks Neil! Old dawgs and new tricks, I reckon...
I like building as much as flying (maybe a bit more, sometimes) and figuring out how to actually make what I have in mind with 'traditional' materials and methods is half the fun.
I get the impression that you feel the same!
I really enjoy following your builds because you do such a good job of "showing your work"; taking us through your thought processes along the way. A lot of fun!
BTW - I often like to remind folks that wood and paper are both carbon fiber, technically...
This build reminds me a lot of my IRIS-T build (different scale subject, but similar approach and techniques). Maybe that's why I like it so much.
One thing I've never really done is built-up fins like this. Gonna have to come up with an excuse to try it at some point.
I'm definitely more about building than flying, which is good since I'm lucky if I get to fly twice a year....
One thing I've never really done is built-up fins like this. Gonna have to come up with an excuse to try it at some point.
I'm definitely more about building than flying, which is good since I'm lucky if I get to fly twice a year....
You could call your cardboard and plywood rocket with wood glue and epoxy a "carbon fiber polymer composite matrix" structure .... technically.
I made a bit of progress yesterday on a lot of the surface detail stuff. I got the interstage details just about finished and added some weld lines. More on that later...
Like I said above, I added some 1/64" flanges to the balsa strips that were glued into the original mid-fin slots to make them look like hat-section reinforcements welded to the booster to support the interstage. This is a totally fictitious detail that never was a feature of any of the Zues/Spartan variants, but it is used on other rockets and missiles and I thought it added some interest.
I went with a tapered shape for the flanges:
They were sanded to shape and glued on with thin CA:
Next I added weld seams to the perimeter with heavy cotton thread. I didn't get any pics of this process because it kind of requires 2.5 hands and a bit of colorful language to get it done in the first place...
Basically, you take your thread and glue one end in place with thin CA, then stretch it along the line you want and soak with more thin CA and very quickly wipe with a paper towel.
Unglue your fingers from the rocket, sand off any fingerprints and proceed around the flange, then trim the end flush.
Once everything is in place I coat the line with thick CA and wipe most of it off with a paper towel. Two or three coats of thick CA form a small fillet around the thread, which now has a bumpy, slightly irregular texture that does a pretty darn good job of simulating a weld. A bit of sanding will get rid of the excess glue and high spots.
The only problem with this method is that it is VERY hard to see the final result until the first layer of primer goes on. Until then it kinda looks like you've covered your rocket in those rope-bordered wall hangings in a fish restaurant. A little faith is required...
Here is the result of yesterday's "welding". I also did a weld seam along the length of the booster to simulate the seams in the solid motor casing. This is a feature of the Spartan boosters. Finally, a wrap of 1/64" ply was added above the wrap with all the holes. There will be a balsa wrap that goes around this area to simulate a first to second stage attachment clamp. More on that in the next post!
Here's a close up. I might re-do a couple of places that look a bit too wiggly. The white stuff is sanding dust...
Thanks again guys!
Mike
Like I said above, I added some 1/64" flanges to the balsa strips that were glued into the original mid-fin slots to make them look like hat-section reinforcements welded to the booster to support the interstage. This is a totally fictitious detail that never was a feature of any of the Zues/Spartan variants, but it is used on other rockets and missiles and I thought it added some interest.
I went with a tapered shape for the flanges:
They were sanded to shape and glued on with thin CA:
Next I added weld seams to the perimeter with heavy cotton thread. I didn't get any pics of this process because it kind of requires 2.5 hands and a bit of colorful language to get it done in the first place...
Basically, you take your thread and glue one end in place with thin CA, then stretch it along the line you want and soak with more thin CA and very quickly wipe with a paper towel.
Unglue your fingers from the rocket, sand off any fingerprints and proceed around the flange, then trim the end flush.
Once everything is in place I coat the line with thick CA and wipe most of it off with a paper towel. Two or three coats of thick CA form a small fillet around the thread, which now has a bumpy, slightly irregular texture that does a pretty darn good job of simulating a weld. A bit of sanding will get rid of the excess glue and high spots.
The only problem with this method is that it is VERY hard to see the final result until the first layer of primer goes on. Until then it kinda looks like you've covered your rocket in those rope-bordered wall hangings in a fish restaurant.
A little faith is required...Here is the result of yesterday's "welding". I also did a weld seam along the length of the booster to simulate the seams in the solid motor casing. This is a feature of the Spartan boosters. Finally, a wrap of 1/64" ply was added above the wrap with all the holes. There will be a balsa wrap that goes around this area to simulate a first to second stage attachment clamp. More on that in the next post!
Here's a close up. I might re-do a couple of places that look a bit too wiggly. The white stuff is sanding dust...
Thanks again guys!
Mike
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Looking fantastic.
Hey, quick question about the 1/64" plywood (which I haven't found a good local source for...): how small a radius can you reasonably expect it to bend without breaking do you think?
Hey, quick question about the 1/64" plywood (which I haven't found a good local source for...): how small a radius can you reasonably expect it to bend without breaking do you think?
To make the balsa interstage clamp, I sanded a 45 deg. bevel into the edges of a 1/2" x 1/16" balsa strip. Then it was soaked in Windex to soften the wood fibers and wrapped around a 4" coupler and left to dry overnight.
The next morning you have this:
This will be cut and glued just above the holes to make the interstage clamp. A few 1/64" ply bits will complete the clamp details.
More later!
Mike
The next morning you have this:
This will be cut and glued just above the holes to make the interstage clamp. A few 1/64" ply bits will complete the clamp details.
More later!
Mike
Attachments
It depends a bit on how wide a piece you want to bend and what it is going around. I've been able to get a 1/4" - 1" or so wide strip to wrap around a BT-20 dry without too much trouble. If you wet it out or apply heat it will go a bit smaller. Wider pieces will bend as tight, but it gets to be tough to keep everything flat against the tube as you roll. For BT-50 and up it can be used just about like cardstock. I like to roll tail cones out of it for impact resistance. This one is over a 29mm motor mount tube and is a little over 1.6" at the big end.
I don't have a local source anymore either. Now I just order it directly from Sig:
https://sigmfg.com/collections/plywood-wingskins
If you aren't familiar with Sig, they are one of the oldest model airplane outfits around. Have a look around their site and you'll find all kids of handy stuff!
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Y'all are gonna make me have to buy a bigger hat if you keep talkin' like that...
Seriously though, you guys are so kind, and coming from you folks, high praise indeed!
Oh, and by the way Paul, I've been following your level 2 build and I don't see any lack of modelling skills there at all! We all have different ways of doing things and that is what makes this place so much fun, we get to see how other folks do things and try 'em ourselves.
Thank you very much Mike …...
I meant to post this in the earlier thread, but this is what the thread "welds" look like after paint. This one is a "scalized" Estes Nike Smoke.
boatgeek
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Balsa was composite before composite was cool.
This build has been really fun to watch.
Got started on the interstage clamp yesterday.
The curled up piece of carbon fiber, um, I mean balsa was cut into three sections that would leave an approximate 1" gap between them at 120 deg. around the tube. There will be little fiddly details in the gaps to simulate the explosive bits that separate the clamps for staging. Again, this is a ficticious detail for the Spartan, but common on other missiles like the Pershing.
You may notice that one of the gaps conveniently lines up with the rail guides so no standoff will be required. Nice thing about fictitious details...
The curled up piece of carbon fiber, um, I mean balsa was cut into three sections that would leave an approximate 1" gap between them at 120 deg. around the tube. There will be little fiddly details in the gaps to simulate the explosive bits that separate the clamps for staging. Again, this is a ficticious detail for the Spartan, but common on other missiles like the Pershing.
You may notice that one of the gaps conveniently lines up with the rail guides so no standoff will be required. Nice thing about fictitious details...
I got the interstage clamp thing all done and have been doing a bunch of detail sanding, so nothing really too interesting lately, but I did get started making the next set of detail parts.
The Spartan had several radar guidance receiver antenna fairings around the upper part of the second stage, but as seems to be usual for this thing, no two pics seem to show the same arrangement. I have pics that show that some had three fairings, some four, and a couple that show six, though I believe these to be mockups. The shape is different as well, some being long and thin, some much shorter and fatter, some rather large, others quite small. Some pic show a hemispherical dome on the trailing edge and others look like they have a hole or port that faces down and a bit outward similar to a Nike Ajax or Herc...
I guess that means I get to pick... I decided to go with three, since it will contrast a bit with the four fin layout. Also going to go with the Nike style ports since the only spherical object I can seem to find in the appropriate size range seems to be a very large ball bearing.
Here are a couple of (lousy) pics showing the fairing config I'm going for. Notice one has three receivers, the other four.
These things are going to be built up from wood, then most likely covered with either silkspan or light glass since they look like the kind of thing that is just begging to get wiped out in a hangar rash incident.
First step was to cut blanks from 1/32" balsa. These are quite a bit oversize just to give me options on final size and to have a bit extra to work with.
Next, they are soaked in water...
...and tightly bound around a nose cone overnight.
The next day you have a fairing skin...
Repeat twice more and we have the basis for the receiver fairings.
Thanks for looking, more soon!
Mike
The Spartan had several radar guidance receiver antenna fairings around the upper part of the second stage, but as seems to be usual for this thing, no two pics seem to show the same arrangement. I have pics that show that some had three fairings, some four, and a couple that show six, though I believe these to be mockups. The shape is different as well, some being long and thin, some much shorter and fatter, some rather large, others quite small. Some pic show a hemispherical dome on the trailing edge and others look like they have a hole or port that faces down and a bit outward similar to a Nike Ajax or Herc...
I guess that means I get to pick... I decided to go with three, since it will contrast a bit with the four fin layout. Also going to go with the Nike style ports since the only spherical object I can seem to find in the appropriate size range seems to be a very large ball bearing.
Here are a couple of (lousy) pics showing the fairing config I'm going for. Notice one has three receivers, the other four.
These things are going to be built up from wood, then most likely covered with either silkspan or light glass since they look like the kind of thing that is just begging to get wiped out in a hangar rash incident.
First step was to cut blanks from 1/32" balsa. These are quite a bit oversize just to give me options on final size and to have a bit extra to work with.
Next, they are soaked in water...
...and tightly bound around a nose cone overnight.
The next day you have a fairing skin...
Repeat twice more and we have the basis for the receiver fairings.
Thanks for looking, more soon!
Mike
BTW - doesn't this look like there should be three of them mounted on a mobile launch trailer of some kind?
(Gotta put that nose cone away; keeps giving me bad ideas...)
(Gotta put that nose cone away; keeps giving me bad ideas...)
Bending that balsa really came out well. I'm not sure I can tell from the photos, did you run the grain along one edge, or straight down the center line? Was it just water? Or did you add anything else to it?
The grain on these was straight down the centerliine. I have molded some balsa pieces with the grain along one edge when it was an asymmetrical piece like a wing tip for an airplane.
These were done with straight water because it was an easy, conical curve. The wrap for the interstage piece was done with Windex. The ammonia helps break down the wood fibers and softens the piece a bit more than plain water and makes it easier to bend along the grain.
Sometimes, when molding a piece with large compound curves or complex shapes I use straight ammonia, but that is significantly less popular with the wife! It is pretty surprising what kind of shapes you can get a piece of wood to take.
I've been meaning to do a techniques thread on molding balsa, but I've been trying to push to get this thing finished up, construction wise anyway. When I saw your Boom project molded balsa shell construction was my first thought. Strip planking was the second! (Looking great, by the way!!
)
These were done with straight water because it was an easy, conical curve. The wrap for the interstage piece was done with Windex. The ammonia helps break down the wood fibers and softens the piece a bit more than plain water and makes it easier to bend along the grain.
Sometimes, when molding a piece with large compound curves or complex shapes I use straight ammonia, but that is significantly less popular with the wife! It is pretty surprising what kind of shapes you can get a piece of wood to take.
I've been meaning to do a techniques thread on molding balsa, but I've been trying to push to get this thing finished up, construction wise anyway. When I saw your Boom project molded balsa shell construction was my first thought. Strip planking was the second! (Looking great, by the way!!
)
I'd be interested in seeing that, I remember the C/L airplane photos you posted with balsa bent in ways I didn't think was possible. Very impressive.
