Planes you'd never heard of

Delvo said:
U-2 never got decommissioned & then resurrected. At least into the 1990s, they had been in continuous use since their start, including for some other countries.

SR-71 did get temporarily brought back once. I have the idea stuck in my head that it was for one of the wars in Iraq, but that might be because I know the same thing happened with battleships at that time and the memory leaked over.

It might seem like the simplest solution for surveillance from above would be to just have enough satellites up there that when one gets too far from the subject another gets close enough. A dozen, for example, would be enough to put them only 30° apart from each other, which would put any point on Earth in line of site to 5-6 of them at all times. A low orbit might mean each one zips by in under an hour, but the job can just be handed off to the next one in line. I long presumed that that must be the way it is these days, although not during most of the life spans of U-2 & SR-71. But it turns out that the number and orbits of satellites that we've actually launched haven't been arranged that way. Given that there are lots & lots of other satellites for civilian functions (or both, like GPS) up there, this can't be because better military coverage would cost too much, so I wonder why...
Click to expand...

Way under an hour.

For example the ISS is in a 400 km orbit. If it passes directly overhead your location, the entire pass from horizon to horizon is over in under five minutes,
Also, keep in mind that spy satellites are usually in much lower orbits, around 130 km to 200 km, and that to be useful, they need to be within a few degrees of directly overhead. Spy satellites usually have only 30 seconds at most in a suitable position for photography.
 
Line of sight isn't good enough. Directly overhead is ideal, and a cone of viewing angles around that is acceptable.

You'd need a ton of satellites for near continuous coverage of the globe entire.

So we make do with less satellites, and a rolling swath of viewing stripes, and occasional gaps in coverage.
 
Delvo said:
This needs some esplainin.
Click to expand...

SpySatFoV.png


Like any camera, those on board spy satellites have a field of view. In order for a target to be in the field of view the satellite has to be within half angle of the field of view of directly overhead.

Additionally, these types of satellites are generally "down-looking" not "side-looking". Anything else would either require excessive use of the satellite's RCS wheels for orientation, or would require the camera body to have a two-axis tilt control system, which is very complex to engineer for space. Both of these attributes would severely shorten the operational life of the satellite. In the case of HEXAGON, it was capable of this sort of reorientation.. they could scan up to 120°, but this would require the retasking of the satellite, involving either or both re-orientation and altering its orbit. Both of these are hard on limited resources, so it not generally done unless the matter is urgent. Under normal circumstances, they would just wait until they had a better pass.

Surveillance satellites such as HEXAGON took a 36 mile by 36 mile image on a 9" x 9" large format film, from a height of 90 to 200 miles. A bit quick of math reveals that the field of view on each frame was.....

at 90 miles = 22.6°
at 200 miles = 10.3°

So, under normal circumstances, for a target of HEXAGON to be photographed, the satellite will have to be between 5.15° and 11.3° of directly overhead.... and as spy satellites go, HEXAGON has a relatively wide field of view.
 
Last edited:
Delvo said:
U-2 never got decommissioned & then resurrected. At least into the 1990s, they had been in continuous use since their start, including for some other countries.

SR-71 did get temporarily brought back once.
Click to expand...

Thanks. I had that the wrong way around.
 
Last edited:
...the latter of which, like the U-2, had its replacements designed, tested, & put into production, and were found to do the job better, but got budget-cut into numbers too small to actually replace them, so the full replacement didn't happen. (And with B-52, it happened twice.)
 
smartcooky said:
[qimg]https://www.dropbox.com/s/eaiklvnp4wxauw1/SpySatFoV.png?raw=1[/qimg]

Like any camera, those on board spy satellites have a field of view. In order for a target to be in the field of view the satellite has to be within half angle of the field of view of directly overhead.

Additionally, these types of satellites are generally "down-looking" not "side-looking". Anything else would either require excessive use of the satellite's RCS wheels for orientation, or would require the camera body to have a two-axis tilt control system, which is very complex to engineer for space. Both of these attributes would severely shorten the operational life of the satellite. In the case of HEXAGON, it was capable of this sort of reorientation.. they could scan up to 120°, but this would require the retasking of the satellite, involving either or both re-orientation and altering its orbit. Both of these are hard on limited resources, so it not generally done unless the matter is urgent. Under normal circumstances, they would just wait until they had a better pass.

Surveillance satellites such as HEXAGON took a 36 mile by 36 mile image on a 9" x 9" large format film, from a height of 90 to 200 miles. A bit quick of math reveals that the field of view on each frame was.....

at 90 miles = 22.6°
at 200 miles = 10.3°

So, under normal circumstances, for a target of HEXAGON to be photographed, the satellite will have to be between 5.15° and 11.3° of directly overhead.... and as spy satellites go, HEXAGON has a relatively wide field of view.
Click to expand...

(Note that my original remark was not about satellites replacing ALL types of spyplanes, just a given hypersonic drone with an appalling loss-rate, even not counting enemy action)

What you write above makes perfect sense, but many of those factors also apply, to greater or lesser degree, to spyplanes. Essentially, the spyplane, going lower, can get sharper pictures, but they are also plagued by vibration and buffeting by turbulence.

I think the difference may be more a matter of application.

Satellites are strategic: You can conduct a continuous long-term observation of enemy held territory without risk of getting shot down (as of yet, at least). And the enemy can do little but try to hide his stuff when he knows satellites are overhead.

Recon planes are tactical: You can find out what is happening just now, but at a higher risk. You have an element of surprise, but you are vulnerable.

Possibly, in the not so distant future, we shall see expendable drones that get dropped from high altitude, swoop down and take hig-res pictures, transmit them to a satellite link and then self-destruct.

Hans
 
MRC_Hans said:
Possibly, in the not so distant future, we shall see expendable drones that get dropped from high altitude, swoop down and take hig-res pictures, transmit them to a satellite link and then self-destruct.
Click to expand...


Photobombs! What a great idea.

Depending on the size of the "self-destruct" charge, could also be useful for taking a picture of your target for posterity, just before blowing it up.

"If you see one coming, smile!"
 
Last edited:
MRC_Hans said:
One reason for the seemingly inferior performance of the B17 was its far heavier defensive armament, up to 13 cal 50 machine-guns. The Lanc had far less and relied on operating at night.

Hans
Click to expand...

The defensive armament of the B17 did not save it. Losses were unsustainable until they introduced long range fighter escorts.

Incidentally, the B17 was vastly superior to the Lancaster in one area: it could fly about 15,000 higher.
 
jeremyp said:
The defensive armament of the B17 did not save it. Losses were unsustainable until they introduced long range fighter escorts.

Incidentally, the B17 was vastly superior to the Lancaster in one area: it could fly about 15,000 higher.
Click to expand...

Mmm, according to data I can find, it did have somewhat higher ceiling, but not that much.

As for armament: Well, the idea that a bomber formation could fight it's way through a determined fighter defense was simply an illusion. As long as they could stay in formation, however, they were no trifle for attacking fighters.

Hans
 
Myriad said:
Photobombs! What a great idea.

Depending on the size of the "self-destruct" charge, could also be useful for taking a picture of your target for posterity, just before blowing it up.

"If you see one coming, smile!"
Click to expand...

Ya, that would be the thing. I was thinking of drones in the range of commercial (fixed wing) drones, so the practical explosive payload would be modest, but ... trust military experts to create some mischief from it.

Certainly, commercial drones are being used for bombing in the middle-east.

Hans
 
Mark F said:
A more recent also-ran few have heard of; The Dassault Mirage 4000. Big brother to the Mirage 2000.
https://en.wikipedia.org/wiki/Dassault_Mirage_4000
Click to expand...
Some fun oddballs for anybody who likes fighters with delta wings & canards...

An F-15 with canards:
https://pbs.twimg.com/media/DUCZPzzUMAAWgiG.jpg

(Notice it also had flat horizontal paddles for its engine nozzles, like F-22's thrust vectoring system. This thing actually had those nozzles and more conventional-looking round nozzles at two different times, for experiments on two different thrust vectoring systems together with the canards.)

An F-4 with canards:
https://i.redd.it/gepjojlmz8p11.jpg

Weird how they just stuck canards on planes that already had tail fins but didn't build one with only the canards and no tail fins, which ended up as the standard way to do canards

A delta-winged F-16:
https://i.pinimg.com/originals/51/7b/9d/517b9d4f0d3970e125218093be976d15.jpg

Another delta-winged F-16:
https://i.pinimg.com/originals/51/7b/9d/517b9d4f0d3970e125218093be976d15.jpg

(Although this angle doesn't show it well, this one was made with its left wing slightly longer than its right wing, the same in the back & middle of the wings but extended farther forward at the front, to collect experimental data on both versions.)
 
You must log in or register to reply here.

Back
Top Bottom