The following are questions frequently asked about the DG-650.
Q:What is it filled with?
A:Helium. Helium lifts about .95 oz per cubic foot. While both hydrogen and helium are lighter than air, Hydrogen is highly flammable, while helium is inert.
Q:Where do you get Helium?
A:It is universally available wherever heli arc welding supplies are sold. Alternately, some chain stores or party supply houses sell bottled helium.
Q:Where do you fly it?
A:Indoors only. Even a gentle breeze would make it difficult to fly outdoors. Gymnasiums, hangars, and halls are ideal
Q:How much does it weigh?
A:With no helium, about 1.4 pounds. Useful load is about 15% of the total weight. When helium filled it is ballasted to neutral.
Q:What powers it?
A:A 350 mAh 3.6 volt NiCad driving four geared electric motors
Q:How long can it fly?
A:Depending on how fast and how much maneuvering, anywhere from 15 minutes to indefinite. Usually :30 minutes
Q:What's the difference between a blimp and a dirigible?
A:There are three classes of lighter than air structures,
1)Balloons and blimps, which manitain their shape with the pressure of the lifting gas or positive pressure air around or in the lift gas. The useful load is nearly always found at center and below the "bag".
2)Semi rigids. These are really blimps with a support structure attached so things can be placed laterally or longitudinally on the structure.
3)True rigids. These have an internal frame and are the same shape inflated or not. Frequently, items are located on the sides (engines) or front (command gondola), center (passengers or cargo), or rear (engines or ballast).
Q:What is it covered with?
A:Aluminized Mylar.
Q:How long will the helium stay in?
A:Depending on the leak rate (almost all RC LTA light enough to fly will leak some helium), anywhere from a few hours to a few days.
Q:How small can dirigibles be made?
A:Practically about 9 feet. This is more of a budget consideration than anything. Bigger is cheaper and easier, but then you run into the far end of the scale on storage.
Q:How big can dirigibles be?
A:No practical limit. LZ129, the Hindenburg, was 803 feet long and displaced over 7 million cu.ft. of hydrogen .
Q:Can it be built as a scale model?
A: Yes, but with a weight penalty.