Model Boat Mayhem

The Shipyard ( Dry Dock ): Builds & Questions => Yachts and Sail => Topic started by: dreadnought72 on September 10, 2010, 06:51:40 pm

Title: Lead bulb
Post by: dreadnought72 on September 10, 2010, 06:51:40 pm
Hi there,

I hope this is useful to anyone.

THIS IS A LINK (http://www.thefreckledfish.com/eppler520_133.png) to a lead bulb in .png format, HERE'S THE SAME ONE (http://www.thefreckledfish.com/eppler520_133.jpg) as a .jpg. The centre of gravity is shown. Right-click and "save as" if you fancy a copy.

It's an accurate form for the Eppler 520, scaled here to be about 133% fatter than the airfoil, and the images are at 300 dpi. (They'll look too big on a screen set to a 72dpi or 96dpi resolution, but if printed at 300dpi it'll be correct - about 28cms long and around 6cm in diameter.)

If cast in lead, it'll mass 9.5 lbs or ~4310 grammes.

You can scale it up or down, if need be. Scaling will change the volume, and therefore the mass. For example:

Scale all dimensions => 120% = 1.2 times all linear dimensions = 1.2^3 = 1.728 times the volume and mass

If you change the width, you'll change the cross-sectional area and therefore the mass. For example:

Scale the width => 80% = 0.8 times the width dimensions = 0.8^2 = 0.64 times the volume and mass

The centre of gravity won't change with scale, of course.

Andy