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  • SteveDaPirate
    replied
    Originally posted by Officer of Engineers View Post
    Jumps don't allow you time to steer. You jump. You look up and if you don't see your big umbrella, you open your reserve chute. Then you hit the ground. On combat jumps, you don't even have time to open your second chute. If your primary fails, you're hamburger.
    I guess I can see the rationale if jumps are commonly very low to the ground. Now that I think about it, most of the jumps are probably taking place at night. No reason to bother with steering if you can't see where you are going. Probably more likely to run into someone else if you are flying forwards and steering than if you just descend straight down.

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  • SteveDaPirate
    replied
    Originally posted by Doktor View Post
    Guys,

    What is the difference between land based naval bomber and regular tactical bomber? I am asking about the design, maneuverability, not the ordnance.
    You can see several differences in design choices for modern designs in each roll by comparing the P-8 to the F-35.

    CAS and Air Interdiction roles performed by a tactical bomber put more emphasis on maneuverability, stealth, and the ability to make high speed dashes. This can help tactical bombers approach radar defended targets by hugging the ground and using terrain features to mask their approach. A tactical bomber has to be able to sneak into and hit specific areas that are often well defended but don't typically move.

    The P-8 as a naval bomber puts far more emphasis on extended range, long loiter times, strong sensors, and signals intelligence. Naval targets aren't as obliging about staying in one spot as a base on land, and thus the ability to stay up in the air long enough to find your target is critical to being able to attack it. Naval bombers also can't take advantage of using terrain to mask their approach, and thus attacking from a long standoff range is preferred so as to avoid having the targets shoot back.

    While you weren't as concerned about ordnance, it plays a role in the design of the aircraft. A tactical bomber can get away with using shorter ranged ordinance like guided free fall bombs, or short ranged missiles, which allows for a low ordinance weight per target hit. A naval bomber attacking from long range makes much greater use of standoff weapons like cruise missiles. While cruise missiles allow a naval bomber to attack from extreme range, they also require that the bomber have sensors powerful enough to identify and track a target at those ranges.

    While cruise missiles combine very long range with very capable sensors of their own, this comes at the cost of large weight and size. A cruise missile with a 500 pound warhead generally weighs in at about 1500 pounds and has much larger dimensions than a guided bomb of equivalent explosive power. This means that naval bombers have to be quite a bit larger than a tactical bomber in order to hit the same number of targets with an equivalent amount of ordinance.

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  • Officer of Engineers
    replied
    Originally posted by SteveDaPirate View Post
    Anybody with knowledge of the paratroopers know why they are still using round parachutes?
    Jumps don't allow you time to steer. You jump. You look up and if you don't see your big umbrella, you open your reserve chute. Then you hit the ground. On combat jumps, you don't even have time to open your second chute. If your primary fails, you're hamburger.

    Leave a comment:


  • Doktor
    replied
    Guys,

    What is the difference between land based naval bomber and regular tactical bomber? I am asking about the design, maneuverability, not the ordnance.

    Leave a comment:


  • SteveDaPirate
    replied
    Anybody with knowledge of the paratroopers know why they are still using round parachutes?
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    Everyone that jumps for sport uses modern Ram-air steerable designs that open more predictably, offer better control over decent rate, can steer extremely well, and allow for very soft landings if you flare properly. The things are smaller and lighter to boot since they actually generate lift rather than just drag. Yet it seems like only guys who use modern parachutes are the special forces or demonstration teams.
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    Is it just a matter of being easier to train guys on rounds that don't give you much control, as opposed to learning to maneuver and flare a modern design? Is it too difficult to coordinate a designated landing site if guys are free to fly wherever they want after exiting the aircraft?

    Anyone have any insight into the logic of sticking to the rounds when seemingly better options have all but replaced them in the civilian world?

    Leave a comment:


  • Stitch
    replied
    Originally posted by JAD_333 View Post
    I was also surprised that they got their first kills with 30 cal ammo. Obviously I don't know much about ammo effectiveness.
    Don't get me started . . . oops! Too late!

    As with everything else, there was definitely an "arms race" vis-a-vis aircraft ammunition during WWII. Most fighters of the period were initially armed with rifle-caliber (≈.30/.303 caliber, or 7.92mm) guns (i.e.: Spitfire with eight .303 machine guns) but, as the war intensified, it became evident that fighters would need to be armed with at least .50 caliber weapons or larger. As the War progressed, fighters were increasingly up-gunned to the point where most fighters (most notably the F4U-1 Corsair and Spitfire Mk. XII) were armed exclusively with 20mm cannon. The P-38 was probably the only pre-war design to initially carry a cannon larger than 12.7mm

    For the Germans, it was even more important to carry heavy cannon and large-caliber (.50 cal+) machine guns, as they were increasingly combating large numbers of heavy bombers over the Reich. Hence, the Me 262 with it's unprecedented four 30mm heavy (though low-velocity) cannon; by the end of the war, it was the most heavily-armed fighter aircraft in the world, and could easily dispatch a heavy bomber with two or three well-aimed cannon rounds. And future aircraft designs, such as Ar 234 and Go 229, were slated to carry a combination of 20mm and 30mm cannon.

    Even more indicative of the aircraft arms race, at the very end of the war the Germans came up with a revolutionary aircraft cannon that formed the basis for many post-war auto-cannon designs; this was the superlative Mauser MG 213, which was later more or less copied for the British ADEN, French DEFA, and American M39 auto-cannon. It was a stepping stone to the later, full multi-barrel designs, like the GE M61 and GAU-8/A Avenger.

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  • Dan_Bickell
    replied
    Originally posted by Stitch View Post
    I knew that two P-40 pilots managed to get airborne during the Pearl Harbor raid, but I didn't know they'd shot down so many Japanese aircraft (even a Zero!).
    More than just those two got up. Do a search for "George R Bickell Pearl Harbor", and you'll find a few articles (new and old) about "Uncle George" (his nickname, but he also happens to be my uncle). He got up in his P-40 during the 1st wave, went down in the harbor, swam to shore, and got up in another P-40 in time for the 2nd wave. He got a few kills as well.

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  • JAD_333
    replied
    Originally posted by Stitch View Post
    I knew that two P-40 pilots managed to get airborne during the Pearl Harbor raid, but I didn't know they'd shot down so many Japanese aircraft (even a Zero!).
    I was also surprised that they got their first kills with 30 cal ammo. Obviously I don't know much about ammo effectiveness.

    Leave a comment:


  • Stitch
    replied
    Originally posted by JAD_333 View Post
    How well is this known?

    I knew that two P-40 pilots managed to get airborne during the Pearl Harbor raid, but I didn't know they'd shot down so many Japanese aircraft (even a Zero!).

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  • JAD_333
    replied
    How well is this known?

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  • mako88sb
    replied
    Originally posted by SteveDaPirate View Post
    Okay. Thanks. I just checked into it more and I guess the main point is that because it was designed as a short range aircraft, they felt the extra weight and complexity of a sealed door didn't offset the fuel savings cost realized from that extra little bit of streamlining. Seeing as it's such a successful design, I'm not one to argue about it. Always seemed odd to me but now I know.

    Leave a comment:


  • SteveDaPirate
    replied
    Originally posted by mako88sb View Post
    Something I've always wondered about but somehow forget to ask is in regards to why some aircraft such as the Boeing 737 don't have the the main gear fully enclosed behind doors when retracted?
    http://www.b737.org.uk/landinggear.htm

    Notice that none of the 737 series have ever had full main gear doors. Instead the outer wall of the tyres meet with aerodynamic seals in the wheel well to make a smooth surface along the underside of the aircraft. The first few 737's had inflatable seals which were inflated by bleed air when the gear was either up or down and deflated during transit. The landing gear panel had a NOT SEALED caption which would illuminate during transit (normal), if it illuminated at any other time you could have a puncture and the seal could be depressurised with the GEAR SEAL SHUTOFF switch to save bleed requirements.

    These were soon dropped as being too complicated and a similar drag and noise advantage was achieved with the present fixed rubber seals.

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  • Dazed
    replied
    Originally posted by gunnut View Post
    This is a general aviation question.

    I was just browsing Wikipedia (some people browse youtube, I browse wiki) and I came across the engines used in light aircraft like Pipers. I noticed the Piper Seneca uses 2 flat-6 engines with 220hp @ 2800rpm each. The displacement is 5.9L.

    Continental IO-360 - Wikipedia, the free encyclopedia

    My question is why such huge displacement for such low power rating? Is it possible to use more modern auto engines with higher power ratings with less displacement? Or even use some tricks in auto engines to boost power in these aero engines?
    Gunnut

    Economics. In number of gallons sold. One day of auto gas used in the US, is more than all the avgas sold in a year. The days are numbered but lead is still in AVGAS. The engine technologies date back to the late 1940's early fifties. The best power to weight ratio on a GA aircraft is an Extra 300 of 6.3 to 1. Comparing aircraft to auto engine? The environmental changes encountered driving your car two miles is not quite the the extreme change as going up two miles up. FADEC can solve a lot of that, but... replace a TSIO-520 with a Mercedes/Thielert engine and you have to lug an additional hundred pounds of coolant. The cost of the Thielert is three times as much. Oh and they are now out of business. The number of Senecas and Barons built in a year, single digits.

    G

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  • mako88sb
    replied
    Something I've always wondered about but somehow forget to ask is in regards to why some aircraft such as the Boeing 737 don't have the the main gear fully enclosed behind doors when retracted?
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    I just assumed they would be fully enclosed for better streamlining and fuel savings. Obviously they wouldn't be doing it this way without a valid reason but I can't figure it out. Hopefully not something that should be painfully obvious to me. lol

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  • 85 gt kid
    replied
    Theres also the LS7 a 427 that comes in the reproduction P-51 Mustangs. I think you can get the LS3s in them too.
    Last edited by 85 gt kid; 17 Dec 14,, 16:34. Reason: typo

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