Weird World War 2 Facts

evangilder · 07-24-2005, 08:59 AM

Keep in mind that the Dopler effect is essentially the principle behind radar. It is how the wave is reflected and changed when it returns to the antenna. To give a great example of Doppler shift, stand next to a train. As the train approaches, the sound appears to go higher. This is caused by the waves compressing as they travel toward you. After it passes, the picth changes again because the waves are stretching as they travel away from you. They aren't really stretching and compressing, they just get that way from the movement of the object.

So how the wave is returned to the radar indicates the direction of the aircraft in the radar range.

Nonskimmer · 07-24-2005, 09:08 AM

See? I told ya there were better people to explain these things.

DerAdlerIstGelandet · 07-25-2005, 01:38 PM

Quote:

Originally Posted by batsguy

sorry about the Vague...What I understand is that this Mark Willey worked on the Me-262 project...there was a recent (1943) quote about a request by Adolf Hitler for info on the bomb rack implementation on the Jet. Apparently this Mark Willey worked under Herman Goering. I just wanted to know if there was some history on this guy.

I could not find anything on this guy at all except for a musician and an author.

batsguy · 07-25-2005, 02:07 PM

Quote:

Originally Posted by KraziKanuK

Udet,
as Lune said the Hitler's order to make the 262 a bomber did not hold back the a/c. Messerschmitt was all ready looking at attaching bomb racks to the a/c before Hitler's order.

When Goering told Willey that Hitler wanted bombs on the 262, Willey replied that 'we have always provided for 2 bomb racks' When asked how long to add, Willey replied '2 weeks'. The only thing to be done was add fairings to the racks. This was on Nov. 2 1943.

DerAdlerIstGelandet · 07-25-2005, 02:16 PM

He is talking about Willy Messerschmitt not a "Willy"!

batsguy · 07-25-2005, 04:10 PM

Wow! for a moment there I thought I had an unknown relative working on the 262.

Thanks,
Glenn Willey

vanir · 07-25-2005, 08:24 PM

Quote:

Originally Posted by evangilder

Keep in mind that the Dopler effect is essentially the principle behind radar. It is how the wave is reflected and changed when it returns to the antenna. To give a great example of Doppler shift, stand next to a train. As the train approaches, the sound appears to go higher. This is caused by the waves compressing as they travel toward you. After it passes, the picth changes again because the waves are stretching as they travel away from you. They aren't really stretching and compressing, they just get that way from the movement of the object.

So how the wave is returned to the radar indicates the direction of the aircraft in the radar range.

Yes but my point was, isn't the purpose behind the specificatin of pulse-doppler radar that the technique was not utlised by the technology in early fire-control radars?

And the question remains as to whether then, SARH missiles are guided by pulse-doppler technique (as was my assumption), or by continuous signal strength, therefore making no use of ranging and directional details but simply following the strongest emanations to their source, as has been suggested?

Nonskimmer · 07-25-2005, 09:02 PM

Ah. My bad. I need to refresh myself on basic terminology.

Yes, Semi-Active Radar Homing (SARH) missiles use CW for guidance. The Sparrow is one such missile. "Passive" homing missiles actually home in on emissions from the target. They're either IR (thermal) signatures or radio/radar signal emissions, depending on the missile type. Sorry about that.

vanir · 07-25-2005, 09:28 PM

*bangs head repeatedly on desk*
:P
Okay, I'll try this.

You've got the latest AIM-7F Sparrows on your Canadian Hornet. Sure some AIM-120's would've been nice but the defence budget just isn't there.

You fire one. The aircraft keeps the target painted on its tracking avionics, so the missile can home in.
Is the avionics using pulse-doppler or CW mode at that moment.

Reason I ask is that CW can't do lookdown-shootdown and can't track multiple targets. As far as I know you've got to point the aircraft directly at the target with CW radar.
You can fire Sparrows at multiple targets. This is because of pulse-doppler radar.
Sparrows coincided with the introduction of pulse-doppler. The only SARH AA missiles in US service before pulse-doppler were short range AIM-4's of which you had to fire at one target at a time (but you could get a nuclear tipped Genie variant...).
Same with the overpowered CW radar on MiG-25's, perhaps the reason two MRM IR missiles were carried in conjunction with SARH missiles (so multiple targets could be engaged using multiple seeker head types rather than advanced avionics).

So far it's been said pulse-doppler radars use a CW mode when engaging targets. How are they doing lookdown-shootdown or multiple target tracking in CW mode...by gimballing multiple radar dishes??

Nonskimmer · 07-25-2005, 09:55 PM

*Sighs in frustration, rapidly growing tired of game*

I'll be straight up: Shipboard radars are really my thing. I'm in the Navy, and while the principles are exactly the same, the system-specific qualities of the F-18 radar sets are unknown to me. I've never bothered to research them, but I do know that they're multi-function units that utilize CW and pulse-doppler.

I was unaware that the latest airborne variants of the Sparrow could be fired at multiple targets, as I haven't been keeping up on the latest developments of the AIM-7, but a SARH missile does require CW guidance. That's the whole idea behind "Semi-Active" Radar Homing. If multiple missiles were to be fired at independent targets, they would each require a dedicated CW signal. Perhaps the AIM-7F is "Active" after all? You tell me.

vanir · 07-26-2005, 05:06 AM

No, multiple target tracking and lookdown-shootdown associated with pulse doppler has always allowed multiple target engagement with SARH AAM's since the radar type's inception.

MiG 29's can engage multiple targets with their SARH R-27's simultaneously and can target designate "off aircraft-axis" with the helmet mounted HUD.

Tomcats can track up to 24 and engage up to 6 simultaneously with combined AIM-7/AIM-54 loadouts, but their AA avionics are older.

The Sukhoi "superflankers" can acquire targets at 400km with its multimode doppler with combined search-while-track capability, track 15 and simultaneously engage up to 6 with its typically SARH loadouts (although AMRAAM style R77's may be fitted underwing, the various R-27 SARH types are more commonly loaded with R-73 "sidewinder class" missiles at the outboard stores and ECM pods at wingtips...R77 "AMRAAM class" are more commonly fitted to MiG-29M's).

I think most earlier pulse doppler setups could simultaneously engage up to 2 targets and track about 4, but this is an assumption.
Early fire control radars can engage 1 and track only what is in the immediate field of view (ie. directly in front of the aircraft), I think all they could do is search and range actually.

I should make clear everything I say here is mostly what I can surmise reading Jane's and that sort of thing. I have no real technical knowledge of radar and missile systems.

evangilder · 07-26-2005, 08:27 AM

I am not well versed on missile technology, but I can tell you that there is a big difference between pulse and CW. Pulse is just that, pulsed, meaning that it is toggling off and on, or that it is pulsing through different frequencies. CW means continuous wave. So CW is always on and always at the same frequency. Radar is not a "simple" technology per se, so it is sometimes difficult to put some of these things in laymans terms.

Keep in mind that some of the missiles also have homing/tracking capability and the on-board aircraft radar only paints the target and locks that target to a particular missile. The "fire and forget" technology.

Nonskimmer · 07-26-2005, 11:44 AM

As far as how all of that is actually accomplished through the systems associated with those various aircraft vanir, I don't know. I'd have to trace through the specs myself. Whether it's through some sort of time sharing or whatever, I really don't know. All I can really say is, evan's simplified explanation is spot on, even though I now realize that you desire much more specific information. I hope you find your answers, and quite honestly you've piqued my curiosity a bit as well. Maybe I'll do some light reading and research later.

vanir · 07-26-2005, 11:54 PM

Sorry, didn't mean to detract from the thread so completely.

Interesting WW2 facts...
Hmm...a prewar one, in 1921-22 the militant "brownshirts" or SA of the National Socialist Workers movement numbered 1.3 million in demonstrable, uniformed individuals whereas the German military arguably under Hindenberg, restricted by the Treaty of Versailles numbered some 200,000 total personnel. That meant support and administration included, it was the total personnel allowed in the armed services under the treaty (with a 7.65 caliber weapon, equivalent to the .32ACP in the US the largest caliber allowed).
No wonder the existing government was powerless.

FLYBOYJ · 07-27-2005, 08:55 AM

I think I read somwhere that even though they walked out of the League of Nations, Japan cried foul at the beginning of WW2 because allied aircraft had guns larger than .30. Anyone else recall this?