FLIGHT QUALITIES


Loiter

This is something that airplane drivers say they can do, but truly, the lighter than air craft excels at, not having to use power to maintain lift. For RC models, it requires only very small amounts of power to push around a craft that weighs ounces.

Think about how much force it takes to push around a helium party balloon and you get the idea.

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Powered Flight

Since there is seldom any "wind" to deal with indoors, powered flight consists of propellers that are moveable (vectored) and throttleable. This is called thrust vectoring and you will see this on modern day full size LTA craft. Combined with speed control of the propellers, the degree of manuverability is astonishing. This is not to say it requires no skill. Dirigibles, being somewhat larger and heavier than their blimp counterparts, have inertia. It is this inertia that demands attention, just as the actual airships of yesteryear.

Because a dirigibles fineness ratio (length to girth) is higher, they are more stable than blimps, so they don't bob around so much, and they can tolerate operating closer to air ducts and drafts without getting marginal in control.

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Climbing / Decending

Here is where the dirigible excels in taking advantage of its airframe. Deck angles can be established (the angle of the ground to the long axis of the airframe) and the body can be effectively used to provide lift. Because of the large area involved, large amounts of lift can be generated this way. One can be overballasted and still cruise around with just a slightly positive deck angle to make up the difference. Dirigibles can climb swiftly, as demonstrated by the zeppelins of WW1. It took a hearty airplane to catch one climbing to altitude!

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Turns

Using combinations of thrust vectoring, you can get a 10 foot dirigible to turn 180 degrees in about three times it's length. It is not efficient though. A dirigible will actually turn most quickly at full power. While coasting the rudder is effective in turning until airspeed is lost to drag.

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Coasting

Since there is no need for air across flight surfaces to maintain lift, dirigibles do not glide. They coast. My DG-650 will coast about 60-80 feet from (Vh) full power level flight. The lighter the craft the less penetration it will have. With full reverse from full forward speed it will stop in about 15 feet.

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Rearward Flight

Same as forward flight, except less efficient and slower because the propellers are optimized for forward flight.

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