Page 15 on
http://www.dsto.defence.gov.au/publi...TO-TR-1622.pdf
Page 18 what's that look like
Page 19 look at the basic design-all the heavy batteries are at the very bottom. Provides a keel...just like a belly hook does. You can do pretty much anything else with the middle part of the space..then the top has lighter stuff. Keeps it from tipping over. That would mean you'd have to add lots of weight to the top to make any kind of difference. Equate that to a piece of wood and I'm betting still it don't make a difference. There ain't weight enough there. Wood isn't that abnormal of weight distribution. I've seen pieces where it's very heavy on one end or the other but it's very very few and not typical.