Creating E-M Diagrams - Falcon 4.0 BMS or Strike Fighters?
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This is page 48 ?
Firstly the chart it is for a weight of 25197 lbs which is 100% fuel and 4 x AIM-9M
If the weight was reduced (e.g. it used half of the fuel weight ) then the chart will look very different, same if the Drag index was reduced down from 38.
Also if he was flying a Block 1 to 10 then they would have been even lighter than the Block 15 in these charts 1978 to 1980.
Also a colder day could increase thrust and the chart again……so very possible between somewhere 350 to 400.
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Many years ago when I first flew Falcon 4.0 I was amazed that the F-16C in the sim would bleed its airspeed down if I pulled a 9G turn at around 450 knots at sea level at full AB. But if I was flying at 500+ knots and pulled a 9G turn, the Falcon would just keep on accelerating at 9Gs. Back then someone told me that a jet fighter produces more thrust at higher airspeeds, and that’s why the F-16 will bleed its speed down if you pull a 9G turn at the lower airspeed, and will accelerate at 9Gs when at the higher airspeed.
If you accelerate at the same altitude the thrust output from a jet engine increases as you get faster (to a point)
In the F-16 I think the FLCS gives you a set AoA figure at 9G depending on CAT 1 or CAT 3 off the top of my head.
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this thread will be helpful for drawing EM diagram: https://www.benchmarksims.org/forum/showthread.php?20546-Plotting-EM-diagrams-from-the-flight-model-data&highlight=drag+index
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Many years ago when I first flew Falcon 4.0 I was amazed that the F-16C in the sim would bleed its airspeed down if I pulled a 9G turn at around 450 knots at sea level at full AB. But if I was flying at 500+ knots and pulled a 9G turn, the Falcon would just keep on accelerating at 9Gs. Back then someone told me that a jet fighter produces more thrust at higher airspeeds, and that’s why the F-16 will bleed its speed down if you pull a 9G turn at the lower airspeed, and will accelerate at 9Gs when at the higher airspeed.
Keep in mind that the limiter of the F-16 is making your upper limit relatively benign a turn. At 550 knots, you are not getting much control deflection due to the limiter (even though you are getting 9G).
But doesn’t a jet fighter pull 9Gs at a greater AOA at 450 knots, and at, say, 550 knots pull 9Gs at a smaller AOA? And higher AOA means more drag. If that’s true, do both of these factors impact the sustained turn performance of a jet fighter at higher airspeeds?
- more thrust at higher airspeeds
- reduced AOA to pull Gs at higher airspeeds (therefore less drag)
Do both contribute to the F-16’s ability, and other jet fighters, to sustain a high G turn at high airspeeds?
Thanks,
Starfighter
increased angle of attack does not necessarily mean increased drag (although it can, does for most typical conditions, and probably does in this case). Increased airspeed always (but not really) means more drag.
Simple (to the point of over simplification) example: At -90 degrees alpha, you have more drag than at 0° alpha, even though you have increased alpha to get there. Well, this is a very broad statement and probably not always true (Im thinking of a few shapes that I imagine this does not hold true for).
If you accelerate at the same altitude the thrust output from a jet engine increases as you get faster (to a point)
In the F-16 I think the FLCS gives you a set AoA figure at 9G depending on CAT 1 or CAT 3 off the top of my head.
Not quite… CAT I or CAT III will limit your available alpha. If the available alpha is limited below that required for 9G, then you wont get to 9G. G and alpha are directly related for a given airspeed and gross weight. Unless you vary alpha, airspeed or GW, you cant vary G. Ergo, regardless of CAT switch setting, if you are at a specific alpha, airspeed and GW, you will always have the same G (cockpit G, radial G is a different story).
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This post is deleted! -
Thanks!
I was just studying the sea level E-M chart for the F-16A in the HFFM manual. According to this chart, the F-16A could not sustain a 9G turn at any airspeed. The most it could sustain is 8.5 Gs. However, an F-16 pilot posted on F-16.NET:
“At slightly above 350 IAS and below 5K our early jets would hold 9 gees in burner.”
Could that be possible? The early F-16A sustaining a 9G turn at 350 knots in a level turn below 5,000 ft.? Does anyone have the V-N for the F-16A? Could the F-16A even achieve 9Gs at such a low airspeed - 350 knots?
to be tested at minimum weight and DI = 0
EDIT : just tested ,f16 block15 , WEight 19 000 lbs, DI =0, 9.3G sustained at 5000K at mach 0.63
and if you dont believe me about the influence of W and DI
just go there :
https://info.publicintelligence.net/HAF-F16-Supplement.pdf
look at page 207 and compare the EM chart with the HFFM one page 121
and look how the weight and DI influence the sustained G’s capabilities
There is a reason i didnt draw the HFFM EM charts at 22000 lbs and DI =0
In short : ANY “quote” from a pilot is absolutly of no use if you dont have the engine type, the Weight and the Drag index and the weather conditions with the quote
real pilots quotes have been challenged multiple times in BMS, guess who was right 100% of the time ?
If you want accurate and reliable performance about the F16, FLY BMS
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Thanks very much for flight testing the F-16A in the sim.
What was the lowest airspeed that the 19,000 lb. F-16A B15 at 5,000 ft. could attain a 9.3G turn? Just curious what the instantaneous turn performance is.
Thanks again,
Starfighter
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there is a book available in north America called " the great book of combat aircraft"- it has Em diagrams in the index, as well as detailed developer provided cross sections. I don’t know why my post was erased in this thread, but if you’re interested in data , there is that.
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I don’t know why my post was erased in this thread, but if you’re interested in data , there is that.
If you posted it the day of the server maint., there was an issue and a day’s worth of posting was lost!
C9
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there is a book available in north America called " the great book of combat aircraft"- it has Em diagrams in the index, as well as detailed developer provided cross sections. I don’t know why my post was erased in this thread, but if you’re interested in data , there is that.
Thanks!
What fighters does it have E-M diagrams for?
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Thanks!
What fighters does it have E-M diagrams for?
well i don’t have it with me sir, but if memory serves, it was re published in 2000, so it had the eurofighter, the f-15, the tornado, the f-16, the f-14, i think the f-18, a few other cargo aircraft, the vietnam era, the korea era.
There are different versions of it too, the one I have is very large and oversized, about a 500 page volume and it is in portfolio 35x 15s. it was not a cheap purchase at the time but i’ve never seen something so detailed. I’ll try and find it on amazon and post you a link.