Hacker News Reader

Comment by madaxe_again | Hacker News Reader

I can’t help but think it must be about protecting the aircraft rather than protecting the surface, as in ukraine roads are commonly built out of reinforced concrete slabs, and somewhat less commonly, but still frequently, they are built to take the weight of tanks, and are wide and straight enough to accommodate even large aircraft - there’s a strip of highway north of Mariupol that was originally built to accommodate strategic bombers.

The other thing that they would do is to even out the surface - decades of frost heave has left said concrete slabs pretty uneven, even in a car, never mind a jet, landing.

View on HN

It's really about the surface, which would be quickly destroyed by jet exhaust.

One of the impulses for changing surfacing methods for runways in Soviet Union was early jets ripping asphalt off the surface, for example, though later planes had higher-mounted exhausts that caused less problems.

As for road landing in Ukraine (and other Warsaw Pact countries, and Sweden), it's a mix of special road segments and special aircraft design (for example, consider MiG-29 with its intake shields that close when it's on the ground, and sturdier landing gear on many aircraft)

For a video example, here's a de Havilland Vampire destroying a runway on takeoff at an airshow: https://www.youtube.com/watch?v=gX3_mQZ4gY8

Is concrete used much in Europe? I’d think asphalt is a much more common highway surface material.

In the UK concrete has mainly been superseded by asphalt but there are one or two hold-outs. The M3 motorway (which heads from London down to Winchester / Southampton) has a long (ten miles?) concrete stretch which I drove along every day for years, although this is the exception that proves the rule. The road was noticeably more noisy / rumbly than others.

https://nationalhighways.co.uk/our-roads/concrete-roads/ 400 miles, apparently. But much less common outside of the east of england.

Concrete is also commonly used on heavy industrial estates - if they've got hundreds of 40 tonne lorries making sharp turns every day, they need the durability.

Probably depends on climate. Asphalt handles freezing temperatures much better.

It was used a lot in the GDR (and i suppose a lot in eastern europe a few decades ago).

Ah yes, I remember the distinct sound and the rhythm from the joint lines that the concrete plaque roads made when driving through the GDR as a child.

A lot of Warsaw pact countries, yes, and in Ukraine it was still common a decade ago when last I was there.

Well protecting the surface protects the aircraft - the exhaust from the F-35B version is so hot it melts the concrete and could kick of bits of debris.

Sorry to bother you on a random comment, but is your airship thing still current?

Yes. As with most things it’s taking time to get things moving - I’m still raising an initial round of funding, and am at the “I will if they will” on several counts stage, and am working with a local council to get my hands on a large chunk of industrial park on a grant. Not far off the target, and a few potential investors yet to approach.

It’s going to take a while to go anywhere, but in the meantime I’m working with a couple of aerospace engineer friends/family on solidifying the concept. If nothing else I’m having fun figuring out how to make something the size of a skyscraper fly with next to no energy expenditure.

Reply on news.ycombinator.com