HAB 01-X Project

this is my first post after 6 month im watching this forum.. :)
i got final project for this section...
at my place no one interst at this subject, but after look this forum this section become interesting..:)
and that HAB is my blimp name///:))
im at group, we are seperated for 3 section, first design the shape of envelope, assembly the blimp, and control system at airship
and, after find reference for size, i would like to make 6m blimp with 9m3 volume
and im at control section
that is medium size blimp.. :)
im using hydrogen for gas, it cheaper than helium, although it flammable..
and better lifting force, 11.2 N/m3
the approximate lifting for gas will be 100.8 N
i don't know how to determine the total weight..
is envelope weight also calculated??
i dunno the mylar weight or ployether...

but without determine the weight envelope
i think it can lift more than 10kg

so im using 2 motor
TR 50-65B 350kv Brushless Outrunner (Eq: 4030 AXi
this motor capable to pull up 3000~6000g / 100~200oz
but the weight is 520gr
cos i using it to against the lifting force from gas
is that motor too big for this blimp??
and this is the propulsion system and position will be look a like

for more detail i will send my final progress to this forum, thank you very much all... :)

 )

Hello, Bayu   Thanks for sharing your design with us.   I believe your hydrogen volume of 9 cubic meters should lift about 9.3 kilos or about 21 pounds.   You do not have much weight in batteries and electronics so I assume you have plenty of lift budget left for your envelop.  Do you know the thickness of the plastic?   You will probably be good up to about 5 or 6 thousands of an inch thick, maybe more.   Poly Ethylene is pretty light.   ARe you intending to use small ballonets to compensate for expansion for ascension?  Will  you have any plastic or metal frame work inside?   I suggest you weigh everything and put it on a budget list to see how much ballast you will need, if any.   Thanks for your drawings, they are very encouraging to us to see someone getting a model made.

thank you for answer before :)
im not using any frame inside, i think it more complex,cos we must calculate the frame strength...
and im not using ballonets,cos i dunno how the system is,
are we must using small compressor for suck air to envelope?? or how?

so, for control altitude level,im using variable line of thrust,180degree movement.
and i presume that can make the airship ascended and descended...is that okay??what that can be used?

thank you all.. :)
 

Variable  or  vectored   thrust  is  a   must   have   Item  for good control.  
 A  balloonet is  basically  a balloon inside  the  envelope that  uses  air to  inflate  .  It  keeps  the  envelope   correctly pressurized  as  the   lift gas  shrinks   from  cooling  by  adding  air  to  the  balloon  causing pressure  inside  the envelope . 
  A balloonet  also   can  be  deflated   as pressure increases   from  heating  .
 All  balloonetts do   is  to  keep   constant  pressure  on  the  envelope skin  so it holds a correct   shape as  the  lift gas  cools off   or  heats  up  which it  will do flying outside .

Welcome to the forum.
I don't think you need a ballonette unless you are going to be flying quite high. 

It is hard to say how heavy your motor should be without knowing the details of your design.

Take your lift and subtract all the required weights: envelope, tail structures, electronics, etc. Whatever is left determines how much is left for motors. Motors come last in my opinion.

I construct spreadsheets for this purpose. If you need help with any of the calculations let me know.

if we use balolonetts, is more controller inside gondola,??
cos i think for keep the airship at desire altitude we must setting the pressure inside the envelope by blow or suck the air??

but like dude say, im make this not for high altitude..
so i prefer not using the ballonette

i have download shape design exel file before, but i cant using it..
i dunno how to change the variable and parameter
project excel aero test3.xls (130.0KB)
is that software can use for blimp???