Daily Plan, 4/22/11; a brief discussion about airships

Based upon what JP of JP Aerospace said, he once made an airship the size of a 747. I would assume that he meant the length of one. By using this page in order to get the dimensions of a 747 , and by using the formula obtained here for the calculation of the volume of a cylinder (of the length of a 747 times 2, because his airships are in the shape of a "V".), and this site, we obtain a calculation of 9300 pounds gross lift capacity.  That would have to include all hardware, including the weight of the ship itself.  But JP said that his ship only weighed 600 pounds!  From this, we can deduce that there is sufficient margin to make an airship that can carry some weight.

Other hardware will be needed though, and this will deduct from the carrying capacity of the ship.  For example, you need propulsion.  Plus a power source.  It is interesting that the hydrogen in the ship can be its own fuel and a fuel cell can make power from the vehicles' own lifting gas.  Another possibility for power would come from the enormous surface area of the airship, which would give ample area for solar panels.  These ideas presume an electrical propulsion, but there may be other ways.  If I am not mistaken, JP must be working on those now.  If he plans to get to space with his airships, he will need a propulsion system which will be fairly robust in thrust and isp.

I ran the number originally and forgot to use the radius of the cylinder by using the diameter instead.  This gave an very unrealistic answer of  37,000 pounds gross lifting capacity.  Thus, if you were to double the diameter, lifting capacity quadruples.  This isn't the case when doubling the length.  That just doubles the numbers because the formula is square of the radius.

This short discussion is about all I have for now.  It is a continuation of what I began to post about yesterday.  I'll keep looking for stuff to post on the subject here.  It dovetails nicely with my own experience as a truck driver.  I am thinking of the feasibility of using airships as a way to move cargo and people.