Stalling while inverted

[Krazee]

Something I found out while flying around in the Hornet. Not sure if it's a characteristic or a fault but either way, it's good to know how to handle it if it happens to you (and I thought it would be an interesting topic).

 

 

Now, we know that the Hornet (as well as other aircraft) retract the flaps above a certain speed as a kind of fail safe, which is all well and good. However, what if you inadvertently leave the flaps in full and you merge with a bandit, going below around 250 knts will see the flaps start to kick in, right? Now I'm not so knowledgable about basic combat manouevres or energy management so I don't know if this is a useful thing. However, I do know flaps bring some stability at lower speeds, which is useful in landing. But what if you are in the middle of a dog fight and you're at the top of a loop, is it helping to stabilise or is it messing with your energy management?

 

 

This particular time, I went inverted at the top of a loop and my speed dropped from around 130 knts to around 60knts instantly, a strange behaviour in it's own right. However, the Hornet then behaved like a turtle on it's back, unable to right itself and dropped out of the sky, like a stone. I had no response from the controls so I couldn't roll it or drop the nose to gain speed and even with the engines in full afterburner, the Hornet didn't gain any forward momentum, which again I thought strange. I plummeted to the ground, totally helpless and wondering what had gone wrong. I tried again and found that this action was repeatable.

 

 

 

I tested this with flaps retracted and found that I could recover every time, in fact it was impossible to get the Hornet to stay on it's back as it always wanted to go nose down. This is the behaviour I expected. So I tried with the flaps in full until the Hornet behaved like the proverbial 'turtle on it's back' and then when I retracted the flaps, with full afterburner, the speed slowly crept up to about 80 knts then suddenly jumped up to about 160knts and I could recover. I've heard of the falling leaf but this is not that.

 

 

So, is it a fault or one of those negative characteristic that only appears when you mistakenly leave flaps in full? Be nice to know if you guys can replicate it and what you think.

[Wrench]

The trouble with maneuvering with flaps down (or I suppose up if you're inverted :p) is that they produce so much drag.

This drag will prevent you from regaining airspeed, and will also effect airflow around the control surfaces, making them less effective.

I'd keep them stowed at all time except take off, landing, and perhaps certain emergencies, but I'd verify those procedures with the NATOPS.

[RED]

Sorry, but this is somehow comical. I enjoyed this little trip into a different view about aviation.

 

Don't forget to put the flaps up ;)

The hornet's flight computer will select optimum flaps during your maneuvers.

[Hog_No32]

Keep in mind the alternative to the HALF and FULL switch position is labelled AUTO (instead of OFF or UP) for a reason. If you watch the LEFs movement (TEFs are harder to see from the cockpit) during maneuvering you‘ll see flight computer in action. The TEFs are also extended when the computer feels the additional lift is what the pilot is demanding but (I‘m guessing here) they likely will not extend to full deflection when above 250kts due to the high stress and excessive drag.

 

Btw this is a feature any highly maneuverable 4th and 5th generation fly-by-wire fighter aircraft has.

Edited September 17, 2018 by Hog_No32