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General control line discussion => Open Forum => Topic started by: Pat Johnston on August 17, 2011, 07:12:13 AM

Title: Laser cut sheets for the Hellcat
Post by: Pat Johnston on August 17, 2011, 07:12:13 AM

Here you guys go.  Pasted on are the laser cutting sheets for the Hellcat 566 full bodied stunter.  I thought it might be good for those interested to see how the cutting sheets are laid out.  This drawing contains most all the essential parts for the laser cutting.  If you zoom in (Control and roller on the mouse) you can see how there are interrupted spots on the pieces.  On especially long parts, this has two good qualities.  It holds the balsa from warping so badly from internal stresses and also holds the parts in the sheet.  One other thing of great importance is to interrupt the cut where there is a very acute angle.  If this is not done, the laser cuts over this part, effectively twice and the sharp point provides tinder for starting a burn.  Not good.  Ask me how I know.  Thin parts are not so bad, but thicker ones are dangerous.  The notches for the stringers are offset .003" to allow for the curf of the laser so an accurately cut stringer fits well.  The fatter formers were split into two halves with interlocking tabs to mate the two halves together.
It takes a little time to set up the cutting sheets, but when done correctly, is nice to have.  Laser cut parts for this kind of plane make life so much easier for all builders.  The construction style of a chubby plane like this can be done with a result of a reasonable light competitive weight.
Pat Johnston
Laser Cutting Technology Section
Skunk Works

Title: Re: Laser cut sheets for the Hellcat
Post by: Pat Johnston on August 17, 2011, 11:48:41 AM

Ty,
I'm with you, there, too.  As a matter of fact, my new, beautiful bride is part Italian and totally perfect for me.  Also, the Hellkitty is just right.  Not anemic like those Mustangs, Spitfires, etc...
Pat Johnston
Lover of the Full Bodies
Skunk Works

Title: Re: Laser cut sheets for the Hellcat
Post by: Balsa Butcher on August 17, 2011, 02:24:37 PM

At the risk of getting involved with full-body controversy, any chanch of posting the plans of the similar sized Bearcat? From the pics it looks more stunt-scale (as opposed to scale-stunt) which is my preference - plus kits are available and I would like to add a full bodied, I mean built-up fuselage WWII era stunter to my squadron. 8)

Title: Re: Laser cut sheets for the Hellcat
Post by: Bill Little on August 17, 2011, 10:14:27 PM

Hi Pat,

Thanks for the information and descriptions.  Laser cutting is one of, if not THE, greatest things that has occurred in our building so far!  It just plain makes life so much easier.

Big Bear

Title: Re: Laser cut sheets for the Hellcat
Post by: Pat Johnston on August 18, 2011, 06:19:42 AM

Thanks, Bill.  The art of laser cutting is really tremendous, especially for designs like the Hellcat.  Of course, it would be a rusty knife without the magic and brains of ACAD.  Even then, I have to say that ACAD alone is not all there is.  Having the knowlege on just how to make progressions for the various formers and wing ribs is a huge step forward.
Pete,
I'll make up a separate thread for the Bearcat in a minute or two.
Pat

Title: Re: Laser cut sheets for the Hellcat
Post by: Rick Henry on August 18, 2011, 08:48:48 AM

Pat, When will you be cutting Hellcat (40-46) size kits/short kits?

Thanks
Rick

Title: Re: Laser cut sheets for the Hellcat
Post by: Pat Johnston on August 18, 2011, 12:23:12 PM

Rick,
Any second, now.  Looks like the total cost of all the parts shown on the cutting sheets is going to be $108 including Priority Postage.  I'm actually caught up on my cutting so I should be able to jump on it now.  Would you believe I have even spent time working on my own plane in the last few nights?  Miracles happen!  Send me an E-mail at pjohnston at idahopower dot com with your address.  I'll also send you my latest plans list.
Pat