I did some additional research about the speed of the Hindenberg and why. It comes down to each doubling of the power of the engines only produces 40% additional speed and the size and share of the Hindenburg creates the resistance.
That being said, with 6,000 SHP (shaft horsepower), for an engine which weighs 700kg, this gives us significant benefits over 1930's technology. Also propeller design has improved dramatically.
4 marine diesels used by the Hindenburg could only be driven at 850bhp rather than their max rated 1,300. This is obvious to any mechanic, the harder you drive these engines the less time they last. In the 1930's our materials knowledge was poor. A standard car engine of the day would require a rebuild after 50,000 miles. Today we expect to get 250,000 miles minimum.
So 8 tonnes of marine diesels would produce a usable 3,400bhp and it drove the Hindenburg at around 75mph. Around 40 hours to cross the Atlantic on the northern route. Rather an upgrade on 5 days for the fastest racing liner, but still not as good as the 16 hours provided by the Boeing 314 clipper.
Then again if you wanted to take the clipper you had to get to the port and from the port at the other end. So that added quite a few hours when Airships were more conveniently located.
Now let's look at speeds and modern powerplants.
A 6,000 shp turboprop can be had at 700kg in weight. Twelve of these will weigh 8.4 tonnes and produce 72,000 shp max.
Ignoring propeller design and hull surface design (graphene over canvas and higher deformity strength and low CD coatings), doubling the available cruise hp from 3,400 to 6,800 will bring the speed of the airship up to 105mph. Doubling again to 13,600hp brings us up to 148 mph and doubling it again to 27,200 hp brings our speed to 208 and doubling again to 54,400 just under 300mph.
At 54,400 hp the turboprops would be running at 75%. This is within standard cruise ability of these engines. But another 1.4 tonnes of engines would add another 12,000 shp which would bring it well into the 60% bracket.
Let's take a step back and see what this would have cost us on the Hindenburg in the 1930's. With the engines used, that speed would have required 64 engines. With a gross weight of 128 tonnes. Or more than half the gross weight of the entire airship at that time. For them 300 mph was simply impossible. They could not get it off the ground. Power to weight ratio of gas turbines makes things possible that were simply impossible before. For the weight increase of just one additional Hindenburg engine and some smart engineering to reduce the drag of the engines, suddenly airship speeds move into the same level as fixed wing.
As I write this I'm aware that there are both 10,000 shp turboprops designed for the A400 and a 12,000 shp turboprop designed by the USSR for their Bear military planes. So I'm being conservative here.
At 300mph that brings the no headwind time to cross the atlantic down to 10 hours. Just 4 hours over the time it takes a normal jet liner.
Of course tailwinds on such a ship would contribute far higher over ground speed advantages than a jet liner due to the the wind resistance of the structure.
Naturally a headwind would also cause more loss of time.
Here are some other things. Much of the navigation issues of the early airships were due to their speed and the speed of the winds they had to content with. If your cruising speed is 75mph and your max speed is 85 mph, when you hit a 60mph wind you are standing still with little ability to manoeuvre. If, however, your cruising speed is 300 mph and you have significant power in reserve to deal with headwinds, then your ability to manoeuvre is dramatically increased.
Then landing. Looking at the way we engineer things today compared to even 70 years ago, we see opportunities which were never even considered.
Let us take an example of the Forth road bridge and the new Forth Crossing.
The forth road bridge I have a lot of experience with having driven and ridden motorcycles over in fairly high winds. Speeds were lowered to 40mph and even 30mph and the bridge was often closed.
Note the lack of any wind protection.
Now let's look at the Queensferry Crossing, only recently opened.
Note the wind protection.
From their website.
“Since it opened in 2017, the Queensferry Crossing has never been closed to cars due to high winds, and we’ve only had to divert high-sided vehicles on a handful of occasions.
https://www.theforthbridges.org/news-from-the-forth-bridges/queensferry-crossing-wind-shielding-success/#:~:text=%E2%80%9CSince%20it%20opened%20in%202017,on%20a%20handful%20of%20occasions.
The Forth Road Bridge was opened on Sept 4th 1964. This is the advance in the way we do engineering between the nearly 60 years since.
Looking at the old pictures of airship "airports", there is no reason why the airship landing jetty cannot be rotating and orientated to the wind. Also there is no reason why wind shield barriers cannot raise and lower after landing and before take-off.
So I may be nuts and, perhaps airship mad. But I think that the world as a whole is ignoring a method of transportation which could redefine the way that we travel around the world and also how much we pollute/do not pollute as we do so.
Please feel free to rip any/all of what I've written apart. I don't do math well so I have to extrapolate from what I read which has been simplified to the level I can work with.
