Kula66 Posted July 17, 2005 Posted July 17, 2005 14/18 have them ... need lower speed handling for carrier landings ... most recent fighters have them ... big boost in turning fight. I guess they were considered in the design, especially given the big boost they gave the the F-4E(?) in WVR combat at the time of the Ealges development ... Given it was designed as a king of A2A(at the time), everything new included ... anyone know why they were not used?
Guest Cali Posted July 17, 2005 Posted July 17, 2005 It's called leading egde and I never knew 15's didn't have them.
britgliderpilot Posted July 17, 2005 Posted July 17, 2005 Not certain, but at least one site Googled says that they were considered unnecessary during the design phase. Shrug. It worked well enough anyway, you have to say - big wing and lifting body. http://img.photobucket.com/albums/v121/britgliderpilot/BS2Britgliderpilot-1.jpg
Kula66 Posted July 17, 2005 Author Posted July 17, 2005 It's called leading egde and I never knew 15's didn't have them. Actually, its called leading EDGE :)
Kula66 Posted July 17, 2005 Author Posted July 17, 2005 Not certain, but at least one site Googled says that they were considered unnecessary during the design phase. Shrug. It worked well enough anyway, you have to say - big wing and lifting body. But I guess it means it has a poor turn rate at lower speeds ...
GGTharos Posted July 17, 2005 Posted July 17, 2005 No, it has a pretty good rate - in fact, better than the F_16 at slow speeds. The flanker does better becaus eit has less wing loading at the same speed; however, at the same time LEDs would have aded drag at slow speed, so it may not have helped at /all/. [sIGPIC][/sIGPIC] Reminder: SAM = Speed Bump :D I used to play flight sims like you, but then I took a slammer to the knee - Yoda
Kula66 Posted July 17, 2005 Author Posted July 17, 2005 has less wing loading at the same speed I didn't think wing loading was a function of speed ... just weight and total lift area? Or does G get in there somewhere (and hence speed)? I guess it would add drag and also increase complexity, but the latter is something the 15 had in bucket fulls ... and you only have to use them when you need.
GGTharos Posted July 17, 2005 Posted July 17, 2005 You're right, I wrote that in a very confusing way. Wing loading does not have to do anything with speed. Rather, it becomes important -when- at slow speeds, as in low wing loading is what makes you maneuverable at slow speeds. As for adding complexity and drag (and weight!) I don't know ... adding the slats wouldn't really make it turn better, it would just allow it to turn at even slower speed. Ie. it doesn't change wing loading - extending the wing some on the other hand woudld change -that- in a hurry, or the addition of other lifting surfaces, like Canards, which would at the same time aid in maneuverability, would put the F-15 right on part for slow speed turning and instantaneaous turn rate with the flanker. [sIGPIC][/sIGPIC] Reminder: SAM = Speed Bump :D I used to play flight sims like you, but then I took a slammer to the knee - Yoda
Kula66 Posted July 17, 2005 Author Posted July 17, 2005 adding the slats wouldn't really make it turn better, it would just allow it to turn at even slower speed. It had a dramatic impact on the turn performance of the F-4 ... granted for an aircraft with a higher wing loading
Cobra360 Posted July 17, 2005 Posted July 17, 2005 You're right, I wrote that in a very confusing way. Wing loading does not have to do anything with speed. Rather, it becomes important -when- at slow speeds, as in low wing loading is what makes you maneuverable at slow speeds. As for adding complexity and drag (and weight!) I don't know ... adding the slats wouldn't really make it turn better, it would just allow it to turn at even slower speed. Ie. it doesn't change wing loading - extending the wing some on the other hand woudld change -that- in a hurry, or the addition of other lifting surfaces, like Canards, which would at the same time aid in maneuverability, would put the F-15 right on part for slow speed turning and instantaneaous turn rate with the flanker. Anyone remember the F-15 ACTIVE programme. If there was enough funding available and the F/A-22 was not so feckin expensive some feature from that may have filtered down into an F-15 upgrade programme. Canards and T/V engines. A US equivelent of the Su-30MKI.
GGTharos Posted July 17, 2005 Posted July 17, 2005 IIRC the ACTIVE was cancelled because it either added too much weight or maybe for other reasons - now that the 229's are availablef or the F-15's ACTIVE is so much more viable. [sIGPIC][/sIGPIC] Reminder: SAM = Speed Bump :D I used to play flight sims like you, but then I took a slammer to the knee - Yoda
Cobra360 Posted July 17, 2005 Posted July 17, 2005 I thought the ACTIVE was powerd by the 229s. One of the down sides of the canards was that there was no room for the gun
britgliderpilot Posted July 17, 2005 Posted July 17, 2005 Best bet is that they decided it would have been unnecessary to upgrade the F15s that far. There are TVC kits for most of the US fighter aircraft, IF anyone decides they need that extra edge. Who needs to turn that hard when your goal is to destroy the enemy BVR? USAF (or more accurately, Congress) thinking at the moment seems to be "Don't pay for any more than you absolutely need" . . . . and it isn't necessary to have supermaneuvrable F15s in active service. Back to slats - what slats do is increase the curvature of the wing to produce more lift, through increasing the lift coefficient. Only really useful at low speeds - at high speeds the vsquared term means you've got more lift available than you know what to do with, while at low speeds you're fighting for more lift. While the F4 may have needed more lift in the slow speed fight, the F15 doesn't really . . . . so leave the extra weight and complication behind. http://img.photobucket.com/albums/v121/britgliderpilot/BS2Britgliderpilot-1.jpg
Kula66 Posted July 17, 2005 Author Posted July 17, 2005 Thanks BGP, sure could do with the extra low speed turning ability in LO ... but I guess in RL you just keep firing AMRAAMs until they are all dead!
Cobra360 Posted July 17, 2005 Posted July 17, 2005 Kinda puts 940 20mm rounds to waste, doesn't it. Just strap on the slammers and let 'em rip.
britgliderpilot Posted July 17, 2005 Posted July 17, 2005 Kinda puts 940 20mm rounds to waste, doesn't it. Just strap on the slammers and let 'em rip. Nope - the cannon shells are vital ballast, and are usually always carried for that reason. They designed the F15 to be good everywhere, just in case . . . . try and avoid dogfights if you can, but make sure it excels if you have to get into one. Unlike the British approach (also government-dictated) . . . try and avoid dogfights if you can, and if you can't . . . . errr . . . . run? http://img.photobucket.com/albums/v121/britgliderpilot/BS2Britgliderpilot-1.jpg
Cobra360 Posted July 17, 2005 Posted July 17, 2005 Classic Tornado ADV approach. At least they got ASRAAM to help out in that area now. Typical F-15 load out for me is 6x120s and 2x9s after that I'm running unless its a MiG-23 or something in that league. May challange a MiG-29 into a dogfight and run him outa fuel for the laugh. Then gun him down when he's running for home. BTW. what you think of ED's F-16 and MiG-29 idea BGP, good to see you back around here again.
Kula66 Posted July 17, 2005 Author Posted July 17, 2005 Well the ADV has no choice ... it can't dogfight anything smaller than a Badger ... but boy can in run when low!
bflagg Posted July 17, 2005 Posted July 17, 2005 Back to slats - what slats do is increase the curvature of the wing to produce more lift, through increasing the lift coefficient. Only really useful at low speeds - at high speeds the vsquared term means you've got more lift available than you know what to do with, while at low speeds you're fighting for more lift. also as britglider suggests.. increasing lift is great for angles fighting (sustained turning...solid g turning..etc) but takes away from accelerated vertical plane movements.... it's a balance thing i would think. Thanks, Brett
Kula66 Posted July 17, 2005 Author Posted July 17, 2005 but takes away from accelerated vertical plane movements.... But surely they just get retracted and (apart from the weight penalty) have no effect on climb etc?
Cobra360 Posted July 17, 2005 Posted July 17, 2005 It more keeping the F-15 in the flight envelope it performs best in. The high energy turning fight. This negates the Fulcrum and Flankers low speed turning advantage and makes them fight on your terms.
GGTharos Posted July 17, 2005 Posted July 17, 2005 Actually, it would have a pretty bad effect: At slow speeds, power output from the engines is dimished due to lack of ram-air effect. You just added a bunch of drag with LEDs (And weight) ... I'm sure you can see the disadvantages now ;) As for the gun: It's there to make you feel good, insofar as today's air forces go. If you're out of missiles, YOU ARE OUT OF AMMUNITION. You turn around and go home. Guns engagements have been extremely rare in modern air to air combat. It can still be useful both A2A and A2G, but it is -essentially- a thing of the past. [sIGPIC][/sIGPIC] Reminder: SAM = Speed Bump :D I used to play flight sims like you, but then I took a slammer to the knee - Yoda
bflagg Posted July 17, 2005 Posted July 17, 2005 y'know.. your right.. that skipped my mind... I would figure with the 15, adding a leading edge, would really change the structure of the wing itself and would also force other structural change to accomodate this addition. so I guess we are back to the point before I opened my mouth.... Thanks, Brett
Kula66 Posted July 17, 2005 Author Posted July 17, 2005 Ok ... if I have 2 a/c ... a 15 and a 27, one turning at 350kts 22deg/sec and the other at 220kts 22deg/sec ... who wins? Doesn't the lower speed give you a lower G load and a smaller turn radius allowing you to turn inside the 15 ... if so keeping the speed up doesn't help! (Ignore the G-LOC modelling issue for now). The other guys is always inside your turn! PS> WVR is NOT my strong point ... I'm trying to learn! Got wasted about 10:1 last night by Shogun before he got board :(
bflagg Posted July 17, 2005 Posted July 17, 2005 Would think this is so.. but remember a slower moving aircraft cannot transition to a energy type fight as quickly as a 15 can.. To put this is another perspective... the 15 can go vertical and change the fight parameters quicker that the 27. (of course this is assuming I've got the angles vs energy types correct) if the 15 stays in the same horizontal plane as the 27, then yes.. your statement stands, but the 15 was designed to be a energy fighter also... hence it can take the fight out of the horizontal plane...... Yo-Yo's, going vertical because it can do it to trade alititude for speed.. etc... Thanks, Brett
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