Marko's Bulb Calculator

Marko's bulb calculator was designed for IOM use and so you have to know how to work around to get details less than 1kg
here is a potted guide

link to download

Step 1
- click on file
- select NACA foil
- (I usually use 64A0XX)

Step 2
- click on file
- select Set Bulb parameters
- change target weight to 1 kg (it won't go lower than this)

Step 3
- look at the table on the left of the screen for a say 275g keel bulb it tells you it is between 13 and 14 cm long
- click on file
- select view bulb data
- change the length to the required length to give you the correct weight (for a 275g bulb this is 13.85 cm give or take a bit) for different weights
- use the change options button to refine the length of the bulb untill you get the right weight
- close the view bulb data menu

Step 4
-  click on file
- select print
- select position tab
- change to centre
- select view tab









- uncheck side and sections
- for making a plug from 3/32 balsa change the slice thickness to 0.238125
- if you are using lead to make a bulb directly from slices the thicknesses are as follows Lead Code. 3. 4. 5. 6. Thickness (cm). 0.132. 0.180. 0.224. 0.265 (I haven't tried this hopefully it will work)

Step 5 - Click ok in print menu it should print you out the sections to produce the correct weight keel bulb! A bit of trial and error will see you get it right.