Scratch-built 1/96 Oscar II

[Guest]

jaw dropping, it really is

jaw dropping, it really is very nice!!!!!!!!

are you sure this isnt a static model

[anonymous]

Kevin,
What is the Icing your

Kevin,
What is the Icing your using? I have to do the same thing on the scratch Blueback I'm doing.

Also I see great minds think alike.

Steve



All scratched. Glass epoxy. Glass epoxy molds. sold about 60. Made for the wren 44 or 90 mm EDF.

[sam reichart]

Kevin,
What is the Icing your

Kevin,
What is the Icing your using? I have to do the same thing on the scratch Blueback I'm doing.

Also I see great minds think alike.

Steve



All scratched. Glass epoxy. Glass epoxy molds. sold about 60. Made for the wren 44 or 90 mm EDF.

Steve - is that an ME 163?

sweet looking bird...

[anonymous]

Sam,

No. It's a TA-183 Huckebein.

Sam,

No. It's a TA-183 Huckebein. Thanks Sam!

Steve

[KevinMC]

Steve- It's a 2-part polyester

Steve- It's a 2-part polyester filler. I've since bought some in a similar tube but a different name, so I guess it's pretty widely available. Here's the stuff I've been using though]http://www.subcommittee.com/forum/Materials.jpg[/img]

I always had a soft spot for the Huck. Are you still making them? And I believe that you're right- great minds do think alike... Here's the predecessor to the Ar-234, my kitbashed Facet 2400T. (Yes, it does have an 8-foot wingspan!)

[KevinMC]

I completed one of the

I completed one of the reactor cooling scoops, carved from RenShape. Shown here is the completed scoop and a "blank" from which the scoop was carved.



I had originally planned to carve up all four until I realized that, but for one detail, they're all identical and so a single master will almost suffice for all. The only catch on this is that the aft pair have an enlarged fillet at the root that the front pair do not. What I've decided to do is to use the existing part as my "front master". I'll cast up a copy of that and add the fillet and use that part as my "rear master".

[anonymous]

Kevin,

I love your bird! Hot

Kevin,

I love your bird! Hot dog! I'm working on a big Vampire slowly.

Thanks for the the information too. go to my site there's another Luft 46 bird there I scratched. www.sneill.com

I'm not selling the Huck anymore. eam.net is though. They bought the masters from me and are selling them.

Renshape. Can't find it in LA. Want to work with it bad. Help. Where.

Steve

[KevinMC]

Th P1101 is another nice

Th P1101 is another nice one. It's kinda frightening, the stuff the Germans had on the books (some of which was nearly in the air) by the end of the war.

I snagged my Ren from a local machine shop that does prototype work. I got me a 2" x 4" x 12" brick for a smile and a handshake. Try phoning around, you never know what these places may be willing to let go for a song. (Or less! )

[KevinMC]

After a long week of

After a long week of too much work, I finally found some time on the weekend to get back at the important stuff. Since I can't find the exact prop I need for my OSCAR II, I've begun the process of making them myself. I'll be building them (left and right) using the same process David Merriman uses when he makes his props


Next I trimmed the blade blanks to the correct radius. This was done with a simple jig on my 4" disk sander.







Next I marked the arc that the blade will follow along the outer circumference using a piece of 1/32" Chartpak tape. (I've skipped the math used to determine the thickness of the blank, and the arc covered by the blade blanks, but take my word for it that my 2.15" dia prop will advance by 2" given one revolution.)





Edited By KevinMc on 1141062913

[KevinMC]

Now for the magic...

Using hot

Now for the magic...

Using hot glue the blade blank is mounted to a piece of brass tube with a plywood 'foot tool' to keep everything perpendicular to the tube. I also made a simple block-jig that would hold the tube on the 'foot tool' parallel to the work surface. (Or more importantly, perpendicular to the belt sander.) The whole assembly was lined up exactly with the edge of the belt to that I could sand a helical path into the blade blank. (The block-jig allows the foot-tool to slide and rotate and only constrains the parallelism of the part with respect to the belt.) Ugh! Here's the pictures, I hope this makes sense.





Now on to side two- Using the same technique I made a mating "base" and hot-glued it to a second 'foot tool'. Then, using a piece of brass rod to ensure alignment and hot glue to hold everything together, I glued the real blade blank to the second foot and broke away the first 'foot tool'.



Following the same process as above, I again ground away the excess material to create a 1/32" thick helical "cork-screw" that is all ready to be carved to the shape of the blade.




The blade was once again mated to a sacrificial piece of renshape, this time with the final shape of the blade pasted to the upper surface. This "blade sandwitch" was taken to the belt sander to put the final shape to the blade. Here's the result:



Finally, I glued each blade to a piece of brass tubing for final shaping.



Although somewhat jig-intensive, the result of this technique is a blade master having a uniform pitch across its diameter. Now for some final tweaking, then for a swim in RTV...

[wayne frey]

Excellent, Kevin.Excellent.
I would love

Excellent, Kevin.Excellent.
I would love to display a hull at the Subron 5 this summer in Texas.

[KevinMC]

You mean the one in

You mean the one in August? I'm certain I can accomodate that, Comrade Frey. And I will get a mock-up of my mast mechanics completed shortly as well!

[PaulC]

Hey, Kevin -- that would

Hey, Kevin -- that would be great to see!

[novagator]

I can't wait to see

I can't wait to see the finished sub.

[KevinMC]

Thanks John, that makes two

Thanks John, that makes two of us!

Paul- I'm getting closer, but all I can show for now is mast heads...

But before I get to that, I want to share another hard lesson learned. This story begins with a gift from a well meaning older gentleman in the local boating club. He began scratchbuilding a Nautuilus many moons ago, and saw that many of the things he'd done along the way were very applicable to what I'm currently working on. One of his experiences was casing parts, but he'd done it with a re-useable hot-melt vinyl molding compound, which he most graciously gave to me. (I believe it used to sell under the name Vynamold?) If anyone ever offers it to you, thank them kindly and RUN AWAY!!!

I actually burned my first batch, warmed in a tin can on the stove. The second batch, heated in a decomssionned toaster oven, came out beautifully. So I preparred one of my prop blades for molding in a stainless steel cup.



The results were not pretty! The heat from the molten vinyl also badly distorted one of my propellor blades, and didn't want to release from the RenShape.



Fortunately all is well that ends well- I kept all my prop-making tooling and withing about an hour I had a replacement blade turned out. I'm currently on try number two using the RTV I should have used in the first place...