Sorry I haven’t come up with a copy of the actual rule however.
Actually US 20 runs pretty much coast to coast. If I remember correctly it’s about 10 miles short of the ocean out in Washington or maybe Oregon and starts in Mass. There are a couple sections of it that you could land a plane on it but it wasn’t designed that way. It’s been around a lot longer than the interstate system.
I’m arguing here with no real facts to back me up, but here goes…
Obviously this scenerio wouldn’t work for every military aircraft, especially B52’s, but most fighter and attack aircraft could easily land on a mile stretch of Interstate highway. Most types of supply aircraft could manage it, as well (C-47?).
Remember, in this military fantasy we’re proposing here, the Interestate Highway system is there to supplement existing facilities. And granted, landing on a highway is never ideal, but there are a lot more miles of highway than airstrips in this country.
Ok, you military nuts, go look at Jane’s or something like it and then let us know the landing distance for military aircraft of the 50’s. If it is 5000 feet or less, then maybe we can accept this ‘straight mile every five’ stuff. 
P.S. I don’t think they follow this rule going through the Rockies…
Look, I’m not saying I know what I’m talking about, but this is the way I understand it:
When the Interstates were first built, there was a guide-line that had a certain amount of straight sections for emergency airplane landings, due to it’s military-based birth.
Now, after the first run of interstates were built, it became obvious that not just the military would use them, so when the subsequent batches of interstates were built, those guidelines were not followed anymore.
The trick would be to find out which were the first interstates to open up and how do they look in terms of straight areas on it? And match that data up with later interstates.
Yer pal,
Satan
Well this thread has gotten pretty haphazard so if I get a bit redundant forgive me.
First about the % of land vs. Interstate numbers statement. I can easily see how this idea would get propagated, but doubt it is implicitly accepted as a rule. The naming of Interstates was done taking several factors into considration. First avoiding confusion with existing highways. This has already been touched on, but they simply went opposite of the existing convention. Low interstates at the south, and west. Treating the US as a rectangle with a need for even distribution of interstates, one can see that the % of land estimate is useful, if not a required code. The initial plan called for numbering below 100. So it follows that if you space them evenly the numbering is going to closely appoximate the land area %. This fact is illustrated well here in Illinois. The interstates I-90, I-88, I-80, I-74, I-72 progress from North to South at separation that closely corresponds to their numeric differences. All this gets screwed up when you add new highways, and twist things together in the congested, and asymetrical Northeast. Rule, I doubt it, easy way to estimate areas, probably, used as a approxamite guideline by the originators, quite possibly.
To state some of the obvious conventions. Even=East-West, Odd=North-South, 100’s spurs, 200-900’s bypasses. With the final two digits assigned to the interstate spurred from or bypassed.
About the rule for a straight mile every 5, definately not a absolute rule. Could have been used frequently in the past, but I would credit the simple fact that a straight road is easier to build, and survey. Is it likely that some roads were designed with straight sections in specific locations to accomodate planes, I’d say its certain. But as a all encompassing rule, never.
Not much help eh?
Well I can say that every Military aircraft could land on a road without signifigant damage. The few that are truly huge, and could possibly damage roads are best landed on soft fields in emergency situations, their wheels and gear are designed to operate in these settings. A B-52 has an empty weight of 185,000 lbs, (practical emergency landing weight of 250,000) and 8 huge wheels. This is not alot heavier than many oversized loads frequently on interstates. So no, they won’t tear up most highways.
And after doing a little search I found a couple of road gek websites that may completely contradict my entire post, but i took a while writing it so i am leaving it as is.
http://www.ihoz.com/interstates.html
http://www.theramp.net/n9jig/home.html
http://www.kurumi.com/roads/freeway.html
These people have issues.
Ok, if we need to continue…
A mile is not NEARLY long enough. A B-52 needs about 10,000 ft of runway. The runways that were built specifically for B-52 staging in the 50’s were typically 14,000 ft long, and the concrete in the first 500ft of the runway is about 6ft thick.
A big problem with landing a jet fighter on a road is debris on the road surface. A tiny rock will destroy a million dollar jet engine.
Fighters and smaller cargo planes like the C-130 Hercules would have no problem taking off or landing on 5000’ of pavement, so that’s not an issue.
A bigger issue is WHY? The U.S. battle plans never included us fighting an air battle on our own soil, so why have all these emergency landing strips? And BTW, you would never need them spaced that closely together. At a normal cruising altitude for a military jet, it could glide 20-200 miles in case of fuel starvation or other engine failure. And if the airframe fails, everyone’s dead.
The interstate-as-runway just doesn’t hold up to any scrutiny at all.
An exaggeration I believe, but the cars would be a bigger concern when discussing debris.
I guess it depends what you mean when considering emergency landing strips. Are we saying places for a disabled plane to land? For a plane to land if the airfield is distroyed? Or to act as a substitute for an airfield (Take off, staging, landing)?
In the first case, the pebble theory no matter how literally you take that, is irrelavant. A little engine damage is a small problem to save the aircraft and pilot. For the second two, why the hell would you need one every 5 miles? So basically there is no good reason that legend holds up.
Well, there have been many a.f.u. posts like this one disagreeing with you, but many like this one seem to agree.
Cites either way would help and I’m still looking. Short of some enterprising B-52 pilot trying it out, we’re left with speculation. The AFU debate still goes on, but a consensus seems to be:
- It is possible to land a plane on an interstate.
- It is rarely the best place to land a plane in an emergency situation (what with obstacles like nearby hills, billboards, overpasses, Bob’s Big Boys)
- Taking off after landing there would be a huge pain, if even possible.
- It could muck up the plane and the road
- Little piddly Cessnas-type planes can do it and do do it occasionally.
- Many other countries do have roads with signs specifically saying that a specfic stretch can be used as an emergency airstrip.
(Still experimenting with UBB url code… my apologies if this mucks up the thread)
Back off, man. I’m a scientist.
I searched pretty hard for a cite to, the best I found was B-52 Specs, and IDOT overweight limits. None of which directly lend themsleves to analysis. I’d like to do a psi analysis given the heaviest reasonable craft, and the compessive strength of the road, but I just don’t care that much.
Remember, we’re talking EMERGENCY landings here. Back in the early days of commercial jet service, 707 and DC-8 jets regularly flew in and out of airports (NY LaGuardia, Washington National, Chicago Midway, KC Municipal and Dallas Love to name a few) that had – at best – marginal runways for planes that size. Hell, a 707 once made an emergency landing at the old Columbia, MO airport. Getting it out of there was a bitch, however.
The B-52 is only the worst-case example. As other posters have noted, there were a lot of military airplanes in the late 50s and early 60s that could easily land on a mile of runway.
I’m not saying the original story is fact, but there’s no logical reason why it couldn’t be fact.
Gee, I thought we just presented about a dozen logical reasons why it wouldn’t be fact:
To recap some of them:
[li]The U.S. had no battle plans which included engaging the enemy en-masse in the skies over the U.S.A[/li][li]You wouldn’t need an emergency landing strip every 5 miles, since a disabled airplane can glide much farther than that[/li][li]Roads are often not a good place to land airplanes in the first place, due to the many hazards around them[/li][li]One mile of road is not nearly enough space for the larger aircraft[/li]
I’m sure I’m forgetting some reasons. Basically, this whole thing smells of UL, and it doesn’t make any sense when you inspect it.
Gee, I thought we just presented about a dozen logical reasons why it wouldn’t be fact:
To recap some of them:
[li]The U.S. had no battle plans which included engaging the enemy en-masse in the skies over the U.S.A[/li][li]You wouldn’t need an emergency landing strip every 5 miles, since a disabled airplane can glide much farther than that[/li][li]Roads are often not a good place to land airplanes in the first place, due to the many hazards around them[/li][li]One mile of road is not nearly enough space for the larger aircraft[/li]
I’m sure I’m forgetting some reasons. Basically, this whole thing smells of UL, and it doesn’t make any sense when you inspect it.
There are lot of interesting facts about the Interstate system athttp://redbud.lbjlib.utexas.edu/eisenhower/highway.htm.
But with all the minutia on that page, it says not one word about landing airplanes. So I vote for UL.