Hornet flight model and aerial refueling
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Nope…
…at least, it shouldn’t be.
But bear in mind: when flying to the boom, the boom operator also flies the boom to you - with probe and drogue, it’s all you. At least, that’s how it is in RL.
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The hornet (IRL and BMS) auto trims to 1G in pitch when the stick is centered and AoA is low. Is the lateral trim acting up?
I attempted some formation in the Hornet a while ago and ran into some pretty extreme PIO issues, were you seeing these as well?
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The hornet (IRL and BMS) auto trims to 1G in pitch when the stick is centered and AoA is low. Is the lateral trim acting up?
I attempted some formation in the Hornet a while ago and ran into some pretty extreme PIO issues, were you seeing these as well?
You described the issue exactly.
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Hmmm… maybe try switching between CAT I/III with the key command. You could also do what some real formation guys do, and trim the stick forward a bit so you’re never passing through the “dead zone.”
I’ve never tried refueling in the Hornet, I’ll see if I can come up with any other tips.
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…“1G in pitch”? 1G, but to the commanded AOA…which should be about 5, in cruise. Whatever pitch attitude you get out of that depends on CG…which will vary greatly with fuel levels in tanks 1 and 4. But you should maintain AOA and 1G.
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Whatever pitch attitude you get out of that depends on CG…which will vary greatly with fuel levels in tanks 1 and 4.
Ah, good point, but does BMS model CG in the Hornet?
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…“1G in pitch”? 1G, but to the commanded AOA…which should be about 5, in cruise. Whatever pitch attitude you get out of that depends on CG…which will vary greatly with fuel levels in tanks 1 and 4. But you should maintain AOA and 1G.
The FCS doesn’t really care about AoA and pitch attitude in cruise, it mainly watches G and pitch rate. The fact that it constantly trims for 1G hands off means that changes in airspeed and CG are automatically compensated for.
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The FCS doesn’t really care about AoA and pitch attitude in cruise, it mainly watches G and pitch rate. The fact that it constantly trims for 1G hands off means that changes in airspeed and CG are automatically compensated for.
…yes, it does. Mostly it cares about AoA and not pitch so much (in fact, not at all - pitch is just a byproduct). It watches G and AoA. But it takes CG into account to do that.
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one issue I have seen with the hornet is your throttle. Be sure to not map both left and right throttles. My warthog is about 0.5% difference between left and right values which results in a slight yaw till I unmapped the second throttle.
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…yes, it does. Mostly it cares about AoA and not pitch so much (in fact, not at all - pitch is just a byproduct). It watches G and AoA. But it takes CG into account to do that.
The auto trim is closed loop, it measures the current G and knows the desired G (which is 1, in this case), and adjusts the stabilators accordingly. It doesn’t necessarily know that the CG has changed, but it compensates anyway because it gets rid of any deviations from the desired G.
What I meant by “It doesn’t care,” is that the pitch control augmentation is G command until you reach 22 degrees AoA. The control laws will try to keep a constant stick force per G, with no regard to AoA until you reach 22 degrees. I should have been more clear that I was talking about cruise flight in particular.
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The auto trim is closed loop, it measures the current G and knows the desired G (which is 1, in this case), and adjusts the stabilators accordingly. It doesn’t necessarily know that the CG has changed, but it compensates anyway because it gets rid of any deviations from the desired G.
What I meant by “It doesn’t care,” is that the pitch control augmentation is G command until you reach 22 degrees AoA. The control laws will try to keep a constant stick force per G, with no regard to AoA until you reach 22 degrees. I should have been more clear that I was talking about cruise flight in particular.
That’s sort of what I was getting at when I said pitch is a “byproduct”. The primary command in the loop is AoA, and not pitch. But even so, yes - it does know about change in CG (approximated by the balance in Tanks 1 and 4) and the change in that arm goes in the trim loop; unless/until the pilot overrides with the Trim switch (and that can be nulled by pressing the T/O TRIM button, but only in the pitch axis). The crew may not know, but the system does.
Stick force per G is an entirely different conversation…in Cruise config (flaps up/AUTO and gear up) and level flight the only thing maintaining stick force are Q-feel springs.
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In BMS it seems to me that it is not you flying the probe onto the end of the boom, but getting the jet placed in the correct contact position and then the boom operator puts the end of the boom onto your probe. The sight picture is definitely different than for the F16, but i’ve gotten decently good at getting into the right place sort of quickly. That’s for the F-18C, the E and F models are still just too much of a handfull, I can connect with those but it’s more luck than skill. I agree though , it’s definitely a much higher workload than the viper which is pretty much just easy, by now. Go do hornet AAR for 20 minutes and then try it in the viper, it feels like a vacation (haha)
Also i’ve noticed the differential in thrust, especially in the E/F, when I spool up on the cat, if I have both throttles maxed forward I yaw off to the right in a very visually stunning and dangerous way. I’ve learned to max the right throttle and advance the left throttle only far enough to make the catapult ready. I have done differential throttle in cruise too, which seems to alleviate some of the control issues, but not entirely…
I’d love to hear any inputs to make it better/easier or explain to me how i’m doing it wrong, and how to fix