Comments on: Army “Future”: Fewer Drones

By: pauljs75

pauljs75 — Thu, 04 Jan 2007 07:41:20 +0000

Stumbled upon here doing a search on lighter than air rigid envelope. Anyhow…
I’ll also vouch for a rigid envelope lighter-than-air craft. The outside skin would be a hard, yet thin and lightweight carbon or kevlar composite. The inside would be mylar or urethane bags filled with helium. The entire shape would be an aerofoil, possibly symetric. The way to describe it is that it resembles a “pregnant” B-2.
Advantages? Unlike a conventional lighter than air craft, the hard outside is designed to not deform at higher speeds. Thus you should be able to surpass 100MPH without envelope deformation, so it will not peel like a bananna and self-destruct from resulting turbulence. (Something that seems to be an issue with typical soft-skinned lighter than air vehicles.) This thing could set lighter than air speed records that would embarass the Graf Zeppelin. Obviously, it will tolerate wind a lot better than conventional airships due to its profile and hard envelope.
The other advantage with a rigid composite envelope, is that by designing it as an aerofoil structure — it can do “buoyant gliding”. That is when positively buoyant, you can shift the center of gravity back. The buoyant force will push it up, and displaced air is directed back. So it’s gliding forward as it goes up without any additional propulsive means. (Think of buoyant force acting in the place of gravity in traditional gliding.) Then you can glide downward in the conventional manner by shifting the center of gravity forward and reducing buoyancy. Thus it would be possible to engage in forward flight by simple use of a buoyant/gravitational porpoising behavior. This would be a very stealthy way to approach, as it would make no more noise other than that of the air being displaced by the envelope. Also think of it as a really neat way to slow cruise efficiently. Then again, if you need it — use the props or fanjets and you can cruise at more conventional aircraft speeds.
Definitely not your typical blimp, nor your zeppelin either. Think of it more as a unique “airplane that floats”.

By: Barry

Barry — Fri, 15 Dec 2006 20:01:02 +0000

The biggest obvious disadvantage of airships is wind.

By: Nicholas Weaver

Nicholas Weaver — Fri, 15 Dec 2006 02:55:39 +0000

You give me a contract which would allow me to NOT build to mil-spec and I could do them for $25k/each.
You want it to work with Jitters, and be to mil spec and everything else, $150k is doing pretty damn good.

By: Gordon

Gordon — Thu, 14 Dec 2006 21:38:04 +0000

Interesting note. The FCS Class I VTOL UAV was dubbed the “Flying Trash Can” by some people working on the project. The Army wanted these VTOLs to be $25,000 a piece. The problem is that right now they are $150,000 a piece without a payload.
Me thinks that the Army wasn’t realistic on pricing, and that this may be the reason for Class I scrappin’.

By: Sven Ortmann

Sven Ortmann — Thu, 14 Dec 2006 21:06:59 +0000

Raven is a smaller Dragon Eye …
By the way, in an interesting article about the British troops, Raven doesn’t look well, too.
http://www.nxtbook.com/nxtbooks/mh/dti1106/index.php
pp. 26–28

By: campbell

campbell — Thu, 14 Dec 2006 14:36:21 +0000

(sigh) boy, this sure gets old…but I’ll bite anyway.…
Nope, rigid shell only makes it more sturdy for ground handling and faster speeds.….
(forget what people “know’ about blimps, this is NOT in same class)
(1) airship is silent, doesn’t attract immediate attention to itself
(2) airship as described has some camoflage ability, making it less of a target
(3) at, say, 5,000′ AGL and moving, even at 30mph, its still a difficult target.
(4) rigid shell, of CARBON, with interior of urethane would have at least some stealth characteristics (re: radar), certainly more than chopper
(5) airship can still “fly”, or decend very gradually, even after sustaining multiple hits from ground fire
(6) attracting ground fire would result in obvious successful accomplishment of surveilance missions to find enemy forces…and result in targeting and suppression of same.
bottom line…its a cheap, real, effective tool. and Yes, I’d demo the thing myself to prove it.

By: SC

SC — Thu, 14 Dec 2006 14:20:36 +0000

Airships huh? Do they fly at 35,000 feet? I know the unmanned versions are getting rolled out but there’s something about a slow-moving airship in a country full of RPGs and antiquated AA guns. Does your rigid shell make those bounce?

By: campbell

campbell — Thu, 14 Dec 2006 11:34:57 +0000

this is fun. I’m the airship guy.
I propose, instead of UNMANNED aerial vehicles.…..One Man RIGID SHELLED airships. As easy to fly as hot air balloons, linger overhead time limited only by pilots’ endurance, speed slow about 30mph max, day/night flight.….with a man on board who can make decisions/communicate with ground troops instead of a robot.…who can use various sensors such as infra red, simple eyeball observation.…
such craft would measure about 60′ long, be about 40′ wide, 10’15′ deep.…shaped like Rogallo wing, simple weight shift for altitude control.…upper surface of RIGID shell made of lightweight plastics with thin film solar array for power generation (available now tech)to electric fan engines for day use.…obviously small combustion engine for night.….…bottom of RIGID SHELL covered with E-PAPER which can then be programmed to change color through white,grey,black…(available now tech) or programmed to form distracting/misleading shapes located away from pilot.….…pilot lives in cabin with thin lightweight titanium floor and Kevlar blankets.….….helium is contained within RIGID SHELL in many separate Urethane balloon “cells”.……
like I said, fun!
and effective and do-able and inexpensive and virtually off-the-shelf available, immediately
turtleairships AT hotmail DOT com