First Level 2 scratch build, upscale Estes Shadow

[qquake2k]

Well, I've decided to attempt Level 2. I probably won't fly many Level 2 motors, but I want to do it for the accomplishment. I've decided to scratch build an upscale Estes Shadow (Optima). It will be 5.5" diameter, 95" long, and weigh a little over 10lbs on the pad. It will have a 38mm motor mount (yes, 38mm, not 54mm); it will be zipperless with an ejection baffle; and single deploy with motor eject. The body tubes and nose cone will be from LOC Precision, and there will be no fiberglass. I'll make the fins and centering rings from 3/8" birch plywood. The motor I'm looking at will probably be an Aerotech J350W or J340M, and will take it to about 1900ft.



View attachment Shadow_5.5in_.38.ork

 

[qquake2k]

The components won't be here until next week, but I couldn't stand it - I had to start on something. I decided to start cutting out the centering rings and bulkhead. I don't have a 5-1/2" hole saw, so the first one I marked with a compass and cut by hand on the bandsaw. Turned out pretty good. It'll be easy to clean up on the lathe.

But the second one I decided to try cutting on the scroll saw, and it was a disaster. For some reason, the blade travelled far to the right as I rotated the plywood. Either the plywood is too thick, or the blade is dull, or the blade tension is too loose. Regardless, I'll be cutting the rest of them with the bandsaw.

 

[Slickwilly]

Yea, scroll saws take some practice and they can be frustrating. You always drift to the right so you have to compensate by angling the part and make sure you go slow and your blade is tight.

 

[qquake2k]

Yea, scroll saws take some practice and they can be frustrating. You always drift to the right so you have to compensate by angling the part and make sure you go slow and your blade is tight.

I certainly haven't used a scroll saw very much. I need to get out the manual and learn how to make the adjustments. For now, I think I'll stick with the bandsaw.

 

[qquake2k]

Well, I ran into a snag. As I was using the bandsaw this morning, something hot landed on the top of my foot (I was wearing slippers, I wasn't barefoot). One of the lower blade guide bearings came apart, and the outer race flew off. It took me a while to figure out where it came from, I had to remove the table to get to it. At first I thought I'd have trouble locating replacements. But apparently, ABEC-5 is a common skateboard bearing. There's a skateboard shop less than a mile from me. I'll go today and see what they have.

 

[BlueCollar Rocketeer]

I don't have a 5-1/2" hole saw, so the first one I marked with a compass and cut by hand on the bandsaw.

Q there is an excellent jig you can make for cutting large circles on the bandsaw. Take 1/2" plywood cut roughly the same dimension as your bandsaw deck. Push it through the band until it sits even with your deck. Draw a perpendicular line from the front of the blade to the rightside of your plywood. Mark out your radius on this line. Drill a pilot hole, slightly larger than the screw you will use, and then attach your centering ring plywood to the radius mark on your jig. Now turn on the bandsaw and rotate your centering ring plywood through the blade. Makes perfect circles with ease and they can be as large as the throat on your bandsaw. It's essentially a tramel (sp?) for the bandsaw.

If you need a picture of this setup I can put a jig together in the next day or so and post it.

I agree with Slickwilly that scroll saws can be difficult to work with thicker material. Try the jig and I know you will like it.

 

[BlueCollar Rocketeer]

Well, I ran into a snag. As I was using the bandsaw this morning, something hot landed on the top of my foot (I was wearing slippers, I wasn't barefoot). One of the lower blade guide bearings came apart, and the outer race flew off. It took me a while to figure out where it came from, I had to remove the table to get to it. At first I thought I'd have trouble locating replacements. But apparently, ABEC-5 is a common skateboard bearing. There's a skateboard shop less than a mile from me. I'll go today and see what they have.

That stinks. And yes ABEC 5 is a common bearing. Been there and done that except for the burning foot part:wink:

 

[KurtH]

Very nice. May I use your plans to build one as well?

 

[qquake2k]

Q there is an excellent jig you can make for cutting large circles on the bandsaw. Take 1/2" plywood cut roughly the same dimension as your bandsaw deck. Push it through the band until it sits even with your deck. Draw a perpendicular line from the front of the blade to the rightside of your plywood. Mark out your radius on this line. Drill a pilot hole, slightly larger than the screw you will use, and then attach your centering ring plywood to the radius mark on your jig. Now turn on the bandsaw and rotate your centering ring plywood through the blade. Makes perfect circles with ease and they can be as large as the throat on your bandsaw. It's essentially a tramel (sp?) for the bandsaw.

If you need a picture of this setup I can put a jig together in the next day or so and post it.

I agree with Slickwilly that scroll saws can be difficult to work with thicker material. Try the jig and I know you will like it.

Yeah, I thought about making a jig for the bandsaw. I made one years ago for my dad's bandsaw that I used to use. But my blade is 3/8" wide, and I wasn't sure if it would follow the circle. I'll probably just cut the rest by hand as soon as I get the bandsaw bearings replaced.

 

[qquake2k]

That stinks. And yes ABEC 5 is a common bearing. Been there and done that except for the burning foot part:wink:

Yeah, it took me a while to figure out what burned me. I guess that explains the noise the bandsaw has been making for a while...

 

[qquake2k]

Very nice. May I use your plans to build one as well?

Of course. I wish I could take credit for the design, but all I did was upscale Estes' original design.

 

[chadrog]

If I could ask, why such portly fins? I'd think 1/4 (or even3/16) would be more than adequate.

 

[qquake2k]

If I could ask, why such portly fins? I'd think 1/4 (or even3/16) would be more than adequate.

You're right, and in fact, 1/4" would be more in scale. But I like thick fins, I wanted them to be strong, and I wanted the rocket to be heavy so it doesn't go too high. Even as heavy as it will be, it will still go higher (on a J350) than any of my other rockets have.

 

[bradycros]

You're right, and in fact, 1/4" would be more in scale. But I like thick fins, I wanted them to be strong, and I wanted the rocket to be heavy so it doesn't go too high. Even as heavy as it will be, it will still go higher (on a J350) than any of my other rockets have.

Unlike Low Power Rocketry, weight isn't really a problem in High Power Rocketry. Strength is important. Using 3/8" plywood will have that needed strength.

The 3/8" fins will not even approch looking oversized on a 5.5" body tube, in fact they oughta look pretty darn good.

You could even go so far as putting bevels on the leading and following edges. This will fool the eye and the fins will 'appear' thinner then they actually are.

 

[chadrog]

Unlike Low Power Rocketry, weight isn't really a problem in High Power Rocketry. Strength is important. Using 3/8" plywood will have that needed strength.

The 3/8" fins will not even approch looking oversized on a 5.5" body tube, in fact they oughta look pretty darn good.

You could even go so far as putting bevels on the leading and following edges. This will fool the eye and the fins will 'appear' thinner then they actually are.

Nobody said it would be a problem, or not look good - I was just curious of his decision. The strength is overkill to the third, I fly a 5.5 on J's with 1/8" (unfortified) fins.

 

[bradycros]

Nobody said it would be a problem, or not look good - I was just curious of his decision. The strength is overkill to the third, I fly a 5.5 on J's with 1/8" (unfortified) fins.

My post was intended for qquake2k, not you. I could care less if you fly a 5.5 on J's with 1/8" (unfortified) fins all day long.

 

[qquake2k]

Well, I thought I had an early morning solution to my bandsaw bearing problem. I bought this skateboard for $15 at WalMart. But, alas, it has different bearings in it.

 

[bill2654]

I hate when that happens!

 

[qquake2k]

Unlike Low Power Rocketry, weight isn't really a problem in High Power Rocketry. Strength is important. Using 3/8" plywood will have that needed strength.

The 3/8" fins will not even approch looking oversized on a 5.5" body tube, in fact they oughta look pretty darn good.

You could even go so far as putting bevels on the leading and following edges. This will fool the eye and the fins will 'appear' thinner then they actually are.

I agree, I think the thick fins will look good. I thought about beveling them with my router table, but I think I'll just round over the leading edges instead.

 

[o1d_dude]

Either beveled or rounded over will work and either will look good.

Entirely possible that the rounded over leading and trailing edges will have a bit more drag and result in a better Captain Low-n-Slow launch.

 

[qquake2k]

Either beveled or rounded over will work and either will look good.

Entirely possible that the rounded over leading and trailing edges will have a bit more drag and result in a better Captain Low-n-Slow launch.

Drag notwithstanding, I just think rounded will look better than beveled.

 

[qquake2k]

I couldn't stand it. I had to do something. So I decided to play with my big-boy u-bolt. I had finished cutting out the bulkhead before the bandsaw bearings died, and had sized it on the lathe. Using a guide I printed out, I drilled two 3/8" holes. I use bullet point drill bits whenever I can. I've found that if I only drill until the point penetrates the opposite side, then flip it over and finish the hole from the other side, the holes are a lot cleaner. That's my first 5/16" u-bolt. In addition to Captain Low-N-Slow, I'm also Lieutenant Overbuild. I'm making sure this one is strong!

 

[qquake2k]

That u-bolt sure is a lot beefier than I'm used to! That's a 5/16" quick link to complete the set.

 

[SacEsq]

I am liking it ... always enjoy your builds. Guess I aill have to break out the Optima I got off EvilBay and start the build.

 

[o1d_dude]

How big is that U-bolt anyway?!

I use the Dremel and a cut off wheel to trim the bolt ends to length on my recovery anchors.

 

[qquake2k]

I am liking it ... always enjoy your builds. Guess I aill have to break out the Optima I got off EvilBay and start the build.

Yeah, get it built! Maybe we can have a drag race, although I'm sure yours would win.

 

[qquake2k]

How big is that U-bolt anyway?!

I use the Dremel and a cut off wheel to trim the bolt ends to length on my recovery anchors.

It's 5/16" diameter by a little over 2" wide. Yeah, I usually trim the ends too.

 

[qquake2k]

What have I gotten myself into this time??? Boy that 38mm motor tube sure looks wimpy.

 

[dixontj93060]

Yep, needs to be 54mm for that size rocket.

 

[GrossApproximator]

No kidding; the 38mm does look small. And I think the 29mm motors are big! I can't imagine what these things sound like at the launch field.