Electric Blimp?
 

Or dirigible? Something the size of the Hindenburg or bigger using helium for lift. Skin covered with the lightest photovoltaic cells possible. By day they power electric motors and charge lightweight batteries, by night the batteries take over.

Possible? Zero running pollution; load carrying capacity would depend on size but it need not look like a floating cigar. What about something circular with a hole in the middle? Wing profile through 360 degrees, the hole in the middle lets the air blow clear after it's given lift. Could the machine be steered by altering the wing profile as it flew?

Just a thought.

Whatever shape it is, there would have to be room for advertising on the side. :rolleyes:

Regards,

D-Ray

The Wright Brothers used wing warping on their early flyers but then you don't have a dirigible any more but a blimp. Not sure that a flying banger isn't the best shape though. You have the gas for lift and you need a form that affords directional stability. A disc or an annulus doesn't give you that.

The PV skin is an interesting idea. There's certainly a lot of surface area on the gas bag for that but does such a material exist or would you need to apply photovoltaic cells to a conventional skin?

John

In the past dirigibles the skin was merely for streamlining. The actual hydrogen was contained internally in gas bags. The crew was able to walk about inside the framework. So light weigh PV cells could take the place of the skin.

The Brits built a couple of beautiful airships, The R-100 and R-101. Both were pretty revolutionary in construction techniques and both saw service. The R-100 was a success but, when the perhaps too adventurous and inadequately testedR-101 crashed, the R-100 was permanently grounded.

R-100
http://upload.wikimedia.org/wikipedi...300px-R100.jpg

R-101
http://upload.wikimedia.org/wikipedi...01-at_mast.jpg

R-101, gas bag inside rigid airframe
http://upload.wikimedia.org/wikipedi...-framework.jpg

Not only was the crew able to climb around in the envelope but the passenger and crew spaces were often contained within it. Gondolas for passenger and crew were more a feature of blimps.

John

My Dad took pictures of the R-100 when it came to Canada. They built a mooring tower at the St. Hubert airbase outside of Montreal.:)

The idea has been bandied about in recent times. It usually comes down to speed.
30 mph or 600 mph? Makes a huge difference when travelling 3,000 miles. Besides our effed up politics, it's the same problem that dogs rail travel in the US. It would save huge amounts of fuel, have near-zero emissions and provide a pleasant, interesting travel experience flying low and slow so you can see the pretty scenery. But, here in America it would get zero support.

I can hear it now;

"F**k that stupid balloon. If I want to fly, I'll take a jet and be there in 1/20th the time." Then they'd make some ignorant sarcastic comment about how only "prissy Marxist Europeans fly in balloons", or some such idiotic nonsense.

Regards,
Dave

We went to Colorado on Amtrak SuperLiner, most pleasant experience, excellent food and service. Could have taken one of those flying coffins but they left at 6:00AM and that was when they insisted that you be at the airport two hours befoore departure time. Being somewhere at 4:00 AM is uncivilized.

Modern LTA craft have speed capabilities in the range of 80 - 100 mph with conventional power sources. I don't know whether that would be feasible with PV generation for electric motors. Maybe but current solar powered airplanes don't come anywhere even close to that and LTAs have massive frontal area to overcome.

I think the future for something line a solar LTA craft would be in less speed-critical applications like remotely piloted observation/surveillance aircraft. The key here isn't in speed but in flight duration. Theoretically, these can stay aloft forever.

John

Sightseeing?
 

I wonder how much R & D it would need to get something with the ability to carry say, 100 people (including crew) past safety requirements into the air. The Hindenburg had very heavy diesel engines, had to carry fuel for the engines plus food for passengers and crew. Apart from the initial purchase cost of photo-voltaic cells and their design life, running costs would be low. If tourists are happy to travel through the Rockies behind a steam locomotive, would they pay significantly more than that to look at the mountains from above?

The idea behind the doughnut design was that no matter what direction the wind came from, if the top surface had the same profile as the wing on a plane it would lift. There could be a slight problem in that the ring having a wing profile over 360 degrees means that the wind flowing over and lifting the wing at the 'front' would flow over and hit the wing at the 'back' which due to it having the reverse profile to the one at the 'front' could push it downwards.

The problem with 'simple' ideas is trying to make the bloody things work. The Victorians had the right approach. "You want to build it? fair enough. If it kills you, fair enough. If it kills bystanders, also fair enough; they shouldn't have been standing so close. Well, apart from one or two bits and pieces I guess they're not close anymore"

I don't see a significant difference between the weight of conventional fossil fuel engines and the powerful electric motors a PV LTA (don't you love acronyms?) would need. No weight of fuel to consider, of course, but there are batteries to consider. Need a lot of those to fly through the night.

Then there's the amount of generation required for charging all those batteries versus the amount required on-demand for propulsion. These things have been dealt with on manned and unmanned solar-powered HTA aircraft but, at least at present, these things are very, very slow.

John

Oh, I agree and think it's a wonderful idea. It would definitely be a niche market (Tourism-sightseeing), and I think it would be cool.

As for your comments about the "donut", I believe you're right. I think there ahs already been research into the donut shaped airfoil and it doesn't work very well. Not as an HTA design, anyways, and for the very reason you describe. At the trail edge of a standard airfoil is a natural down draft. In standard HTA aircraft design, there is a troublesome effect called "shadowing". If the horizontal plane of two airfoils is not offset, relative to the airstream, the leading foil will "shadow" the trailing foil with turbulent air, leading to a significant loss of lift and control problems.

In an LTA design, it may be somewhat different as the foil generates lift, even when static, and the speeds are generally lower.

Regards,
Dave

+1.

Dave

I came across this photo this morning so I scanned it in. A picture my Dad must have taken and that is probably my Mom and older siblings in the picture. That was August 1930 so I am also in the picture as I was born that December.

Taken at the airbase at St. Hubert, Quebec when the R-100 visited Canada.

That's very cool Rob.

I agree 100%.

Pete