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Airship Building Basics and Builder Tips –Where to Start
Created by Deadline on 9/16/2013 6:00:31 PM

Airship Races are coming to a Con near you! Airships are iconic in Steampunk and here is your chance to learn how to join in. Follow the Steampunk Chronicles series for makers and airship races.


Airship Races are coming to a Con near you! 

www.facebook.com/events/555137784525677/Airships are iconic in Steampunk. They feature in our books and art, in the names we give our groups, and even in fashion. Everyone wants to be an airship captain or part of her crew. So, it’s natural for us to want to see more airships at Steampunk events. This year, the Steampunk Empire Symposium in Cincinnati, OH, hosted its second annual Dirigible races (It was great fun, see the pictures and video HERE). Also, 2013 marks the Inaugural Airship Races at DragonCon in Atlanta, GA. (DragonCon Facebook)  Rumors has it that airship racing may even be spreading north to TeslaCon, in Madison, WI.  

Remote Control (RC) Airships are not new, per se, but it’s not until you start to race them that it becomes a sporting event. Airship races are fun, easy to host, and draw a crowd. The rules are simple: navigate your craft around the course faster than the other airship captains send theirs and you win. Or one can win on esthetics; simply build the most impressive design. The courses are simple (two or three pylons) , but the captains also have to avoid the hazards of a ballroom (lights, walls, air vents, the floor, spectators and the Master of Ceremonies).  Think of it as all the fun of horse races, inside a ballroom, with all your friends cheering you on, while drinking Pie.     

The basics of lift

Helium lifts, but, when you get right down to it - not very much. *

How much is “not much”?  1 cubic liter of Helium lifts about 1 gram,  give or take for pressure, temperature and relative sea-level.  1 gram. That’s all! So build very light. 

Why? A helium balloon lifts in the same way a boat floats: it displaces. It displaces air and air is pretty light. To get lift you have to displace air with something even lighter. Helium is lighter than air but not by much, just 1g less for each liter or about 28g(about 1 oz) per 1 cubic foot.  So, again I say, build very light.

So how much can my airship weigh?

Let’s do the math. A large (40”) Mylar balloon might displace about 60 cubic liters (2 cu ft.) while an Air Swimmer™ is about 125L (4.5 cu feet). Converting the displacement to lift we find a balloon that fits within most race rules is going to lift between 60g (2 oz) and 125g (4.5 oz.)  That’s not a lot for an RC craft and it seems even less when you realize that number must include:

  • The balloon’s (Mylar or latex) weight
  • The RC gear
  • The propulsion motors and batteries
  • The ship, the paint, the tape the string and all. 

*per the rules, you can only use Helium so don’t bother with anything else.  Helium reference link: http://www.chem.hawaii.edu/uham/lift.html

So what to use?

What materials are  possible to use in building a completive airship that is lightweight (say under 55g, the target weight for this build)?  Fortunately, advances in micro technology and mass marketed toys have come to our rescue make this a reasonable task to accomplish.  For this article we will look 4 areas:

  • The balloons
  • The RC gear
  • The propulsion motors and batteries
  • The ship

My goal was to try to build an airship from things readily available at a party, toy, or big box store. I wanted to keep specialty or “special order” parts to minimum in an effort to make this a sport that the average Steampunk Maker or model builder could participate in and follow. We will cover several airship builds in detail in some upcoming articles but, for now, here are some of the basics.   

The Balloon

There are two key factors in the balloon: size and weight.  While the balloon might seem like the first place to start, it may not be. Getting the right sized balloon is based on what you need to lift and you might not know that until after you make several other decisions. So, I’ll give you a few options to consider as you move forward. Feel free to come back to make a decision later.  For materials there are two, Mylar or latex.  Latex is great in several ways:  it’s very very light, it’s cheap and it is size adjustable. The drawback to latex is the shape. In the size airships we will use the only real option is round and hotdog –shaped. Neither is very aerodynamic but several teams have been able to successfully make that work with some really great airships.

See lift chart below :

Because of the limited shape options of latex, Mylar seems to be the material of choice for most teams. Among Mylar’s advantages, it’s strong, reusable, holds helium for several days, is readily available in some standard balloon sizes, and (if you are handy) can be made in custom sizes and shapes.  Yes, bought by the roll, Mylar can be ironed together and tailored to a required lift size. The big disadvantage is that it is relatively heavy.  Mylar is covered with aluminum. When one calculates the lift volume to the material weight in small sizes there is barely any lift available as compared with the comparable size latex.  

The comparison chart below will provide some of the off the shelf Mylar options:

   Description  Approx. Cost  Weight/Volume  Approx. Lift
 40" Large Number 1 Balloon  $4- 8

 

  26 gram

  About 1.6 cu ft or 46 l

 ~20 grams

 Twin 40" Number 1 Balloons  $8-16

 52 grams

 ~41 grams

  Air Swimmer Replacement Balloon  $5-15 50 grams About 4.1 cu. ft.
1 cu ft = 28.3 l
~116 grams - 50 grams = 66 grams
Twin Air Swimmer Replacement Balloon

 

$10-30 About 9 cu ft. ~230 grams -100 grams = ~130 grams
44 inch Replacement Goodyear Blimp Balloon Envelope for Dragonfly Mach RC Airships

$13-15

43 grams

5 cu ft.

~140 grams
-43 grams
=~97grams

 

For spherical helium Latex balloon sizes:

Dia. In.  Vol. Liters  Lift/gr    Lift/lbs
       6        1.85          1.90      0.0042
        8        4.39          4.51      0.0099
      10        8.58         8.81      0.0194
      12       14.83      15.22      0.0335
      14       23.55      24.17      0.0533
      16       35.15      36.07      0.0795
      18       50.04      51.36      0.1132
      20       68.65      70.45      0.1553
      22       91.37      93.77      0.2067

RC Gear

Ideally an airship remote needs to have at least three channels. That would provide up/down, left (port)/right (starboard) and fast/slow. It’s a race, so backing up or parallel parking is optional. There are quite a number of off-the-shelf RC options

The Spektrum AR6400/AR6410 DSM2
6 Channel Ultra Micro Receiver/ESC.

readily available which provide this functionality. Most of the indoor copters and quad copters provide 4 channel controls, small motors to work with, rechargeable batteries and stay in our weight range of about 10-20 grams. In the toy market, Air Hogs and DragonFly make a number of models that fit the need and can be found at a toy seller near you (or via online auctions).  In the hobby grade products, the Micro and Ultra Micro sized units stay in our weight limits.  Horizon/E-Flite/HobbyZone makes a number of small planes and quads based off their Spektrum AR6400/AR6410 DSM2 6 Channel Ultra Micro Receiver/ESC.  At 3.9 grams with a built in Electronic Speed Controller it’s a very versatile unit that can manage most any airship need.  At first, one might consider the hobby grade units as too expensive but often there are great close-out deals on last year’s hot plane models. Just recently, E-Flight discounted last year’s micro quad for $22 each.  If you are game for a few potential repairs, the used and crashed market can be super cheap. Remember that we don’t need a flying condition plane, just its working parts. I have found a number of crashed remains that worked just fine at a fourth or third their original price.  Also, don’t overlook that broken toy your nephew received at last year’s Christmas.  Most of the time, they get thrown out too make room for this years toys.     

Propulsion

The above is the 37 gram ducted fan unit
and battery used in the PeckTec Airship
The Vortex
from the F-86 Saber

Motors, props, and batteries are what make an airship go. There are several schools of thought here, but “use what you find” seems to be a common theme.  Copters and quads make great airship power sources, but remember your airship must be neutrally balanced so you can’t use quads for lift. Their motor / blade combinations are on thin, easily mountable rods which seem to work well.  One motor, two or three? Pulling from the front, pushing at the back, off the sides pushing and pulling, the options are up to you.  This where your real designing powers and imagination will come in to play. Will you control by tail boom or fin rudders? Shall it be stabilizers or tilting motor pods for up and down? The combinations so far have made each airship unique.

Ducted fans are gaining popularity like The Eleanor Page and PeckTech’s The Vortex, and they might turn out to be a winning combination.  Some of the ducted fan options available include Great Planes F-86 Sabre and the E-Flite Mig. The advantage is simplicity with lots of power. Their disadvantages seem to be weight and short battery life.  If the weight can be managed, I think one could clean up on the racecourse. Fast, small, and maneuverable would be a winning combination.

The Ship

The finished paper craft ship for the
HMS Chronicle weighed in at 17g

The choices here come are all about the steampunk style and keeping it light. The craft, the paint, the tape, the string and all need to stay under about 20 grams (depending on envelop size).  The common materials include: balsa, foam, light plastics, paper, bamboo, foam core, straws and carbon fiber. You will see a lot of very clever making if you look at these ships up close.  Papercraft ships seem to be both light and structural. You can download several free papercraft ships or follow in the footsteps of Captain Stowe’s  the What The Helm. Captain Stowe used SketchUp and Flatteny (both free) to design a 3D ship, apply the graphic designs and then turn it into printable papercraft for his gondola. 

This has been a brief overview of the basic elements. We hope the research compiled here will save you time, gets you over any initial hurtles and help motivate you to join this fast growing Steampunk sport. Stay tuned to the Steampunk Chronicle as we will dive into some of the more complicated and detailed process in future articles.  you can also follow us on the Airship Builder Group

Look for theses Upcoming Airship Maker Articles exclusively here at Steampunk Chronicle

A build history of the Eleanor Page by Airship Captain John Carpenter – Winner of the Inaugural Airship Race
An introduction to SketchUp and Flatteny  by Airship  Captain Stowe
Making your own Mylar balloon By Captain Peck and the Airship The Vortex
Airship Makers Lessons Learned from the Inaugural Airship Race

Relatd Articles
Building Your Own Airship Envelope
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