It will be fun to see what kind of mental gymnastics the devs pull this time to justify the 18,000lbs of thrust in the F15C.
NASA documents https://ntrs.nasa.gov/api/citations/19990064011/downloads/19990064011.pdf show that the installed engine thrust in a test flight for the F15C engine #P680063 was 27,000ftlbs… We are being cheated by more then 50% of our engine power.
Is that unclassifed/ unrestricted?
If so put in a bug report with all of this
Is that peak thrust?
Ingame shows thrust at static position. Ram air will greatly increase thrust and when flying around Mach 1 the engine will create vastly more thrust than when standing still.
27,000 foot pounds / 2.2 = 12,272.73 kgf.
In-game:
14,150kgf. x 2.2 = 31,130 foot-pounds.
13,300kgf at 0.94 mach. x 2.2 = ~29,260 foot-founds.
So, if anything, Doc’s claim would actually “nerf” the engines? Am i understanding this correctly?
Likely it’d be dismissed cause it’s a secondary source, and it doesn’t specify speed.
It was actually during a flight test, where they were attempting to land with the controls locked. The pilot was only allowed to steer using the engines. So its a low speed test.
Already done, and yes, its a NASA public document.
No, because this was a low speed test done on landing. They were testing if the F15C could be safely steered with locked controls. It was.
That thrust value would be done at closer to 85 kias for landing speeds Not at Mach 1.
“The F- 15 was successfully landed without the use of any flight controls (Burcham et al., 1994). The big brute force of engine P680063, with more than 27,000 lb of engine thrust, was modulated with enough finesse (along with the other engine) to gently nudge the F-15, with flight controls locked, to a safe landing.”
This is a low speed thrust rate.
That is completely unrelated.
In the tests you mentioned the plane was nowhere even close to producing that much thrust. Producing that amount would have made landing impossible since you’d be accelerating insanely fast.
You are seeing two different things done by the same plane and conclude they are done at the exact same time.
A car can have 1000HP, can you still park your car into tight spaces in reverse? Do you think the car uses 1000HP in that moment?
See the issue? It’s not wrong to say that the plane has that amount of thrust. It’s also not wrong to say that it can maneuver with it’s engine at slower speeds, but it’s not possible for the plane to have both at the same time.
I mean sure… You CAN use 1000HP to park your car… But I guess you can see why that would not be an ideal situation.
The Thrust of the F-15 is pretty much correct within a small margin of error depending on the sources. What you suggest would mean that the F-15 should have a Thrust to Weight ratio of almost 3, when approaching Mach 1 at low fuel.
An argument made from conjecture can be dismissed with conjecture.
On top of that, the document addresses PW-100, not PW-200.
AKA F-15A’s engine.
And the sentence that uses PW-100’s paper stats AB thrust is unconnected to the landing test sentence. @DocUSMC
Thank you Alvis, but i’m worried that regardless of how much you might explain to him that he’s wrong he’ll keep on making these crazy claims.
F15s newer engines are even more powerful than this. F-15 Flight Research Facility - NASA
Initial ADECS engineering work began in 1983. Research and demonstration flights with the ADECS system, which began in 1986, displayed increases in engine thrust of from 8% to 10.5% (depending on altitude), and up to 16% lower fuel consumption at 30,000 feet and constant thrust.
The increased engine thrust observed with ADECS improved the aircraft’s rate of climb 14% at 40,000 feet, and its time to climb from 10,000 feet to 40,000 feet was reduced 13% at an airspeed of 350 knots (15% at 250 knots). Increases of 5% to 24% in acceleration were also experienced at intermediate and maximum power settings, depending upon altitude. Overall, engine performance improvements (rate of climb and specific excess power) were in the range of 10% to 25% at maximum after-burning power.
Proving we still don’t have enough thrust. Further more. If they were correct, then we could perform this:
I would love to see anyone do this within even 10% of the stated times with the in game aircraft. Do it clean, with minimum fuel (you can’t).
GIve me 1 minute =)
The correct procedure is:
Takeoff in 400 feet.
Hold on runway to 500mph
Pull 5G vertical to 80 degrees.
accelerate to Mach 1.0 within 23 seconds.
Reach 20,000ft at Mach 1.05 39 seconds.
Reach 30,000ft at Mach 1.0 in 49 seconds.
Reach 39,000ft at Mach 0.9 in 59 seconds.
At the time of that test engine #P680063 was configured as a PW1128 EMD demonstrator engine, meaning it had significantly more thrust than the engines used on production F-15s.
No F-15 can do 28,653 pounds, all will be heavier.
Since we cannot remove the Vulkan, and we cannot drop fuel below minimum, ours will always be heavier than that test.
4021 pounds of fuel.
28,204 pounds of aircraft.
My testing is sadly done at less than ideal conditions. I won’t bother doing an exact test for the simple reason of my F-15A being completely stock. When I chose the “reference” option I have either drop tanks which I can’t drop until I am in the air or I have weaponry slowing me down. I also pulled up way too hard at 9G’s.
Yet you can see that even with all those screw-ups, my time to altitude isn’t that far off. I also took too much fuel as I still have a ton of fuel left at the end.
I am not sure how heavy the F-15A at that fuel amount is but I reckon the F-15 used in that test had no weaponry installed, they sometimes even remove the radar and non-needed systems for those trials.
Without seeing all the details for the test it’s really hard to compare it to the ingame model. If we can match the weight it should be quite close though.
I guess the WT model is a bit heavier and since I lost more speed during the harsher pull-up I reckon you can gain a couple seconds from that alone.
EDIT: Also note my struggle with the brakes at the beginning, I was trying to hold them but for some reason my keybindings got messed up therefore there is some weird beginning to the video on the runway. I also couldn’t drop the weapons because I forgot to select them.
EDIT2:
Timestamps
-Start on runway at 22seconds
(That’s when I engaged the afterburner and released the brakes)
-Take-off at 32 seconds
(Could have been earlier if I pulled up earlier)
Mach 0.7 at somewhere around 43-44 seconds
Reach 20.000ft at Mach 0.96 at 1.08
-Reach 30.000ft at Mach 0.92 at 1:19
-Reach 39.000ft at Mach 0.8 at 1:29
Taking away the 22 seconds idle on the ground we get:
Take-off at 10 seconds
Mach 0.7 at 21-22 seconds
Reach 20K ft at 46 seconds
Reach 30K ft at 57 seconds
Reach 39K ft at 1:07 seconds.
And the test was actually done at “current settings” so the plane is indeed stock.
You can make a clean preset without weapons
IIRC you can also disable automatic refuel and rearm on runway
They stripped literally everything they could out of that F-15:
The aircraft was modified by McAir between April 27 and June 11, 1974 for the tests by deleting all non-mission critical systems including: the flap and speed brake actuators; internal armament; the radar and fire-control system; non-critical cockpit displays and radios; one of the generators; the utility hydraulic system; and, of course, the 50 pounds of paint (hence its name)
Yeah, I can’t because I didn’t buy it yet^^.
Test was also performed on “current” which seems to mean “stock” when I compare it against the “reference” setting in local:host.
