AoA Indexer is dependent on the weight?

[RodBorza]

Hello all,

 

It is an F-18 related question, but I will use the F-5 as an example.

 

Yesterday I started to fly the F-5. It is a nice, but tricky plane to fly, partculary on landings. And I believe that the AoA indexer on the F-5 is calibrated for a light airplane, with no stores, no ammo, and 1,000 pounds of fuel. I base that on what is written on page 204 of the F-5 manual, that states you must add so and so knots of speed on the glide slope to compensate for the extra weight.

So, I noticed that I have better landings coming to land with an slight fast indication on the AoA indexer, since I'm a little bit heavier than the computer expects me to be. And I noticed that you must pay more attention to IAS than the AoA indexer to land properly.

 

On the other hand, the F-18 is a different history. Regardless of the weight, loadout or fuel quantity, if I configure the airplane on the proper AoA (the donut) I always have perfect (or almost perfect) landings. Of course, speeds are differnt for each situation, butif it is on the proper AoA, it is guaranteed a good landing.

 

So, my question is: being more modern, with a thousand different sensors and more capable computers, does the AoA indexer on the F-18 adapt to each and every situation, considering differences on weight and loadout? Or my perception is totally off?

[104th_Maverick]

So, my question is: being more modern, with a thousand different sensors and more capable computers, does the AoA indexer on the F-18 adapt to each and every situation, considering differences on weight and loadout?

 

 

Yes sir.

 

 

Rocking up with min fuel and no payload will give you a much slower AoA speed than rocking up with the aircraft at the max landing weight loaded with fuel and weapons.

[GoshawkBall]

On speed is on speed regardless of stores, wait or configuration. What changes is the speed that corresponds with on speed

[RodBorza]

On speed is on speed regardless of stores, wait or configuration. What changes is the speed that corresponds with on speed

 

Wow. Now I understand.

 

The angle of attack is the fixed value. The variables are weight and speed. More weight equals more required speed to maintain the proper AoA.

 

So, the computer doesn't even need to calculate the new speed, it only needs to keep track of the AoA and the adjust on speed will come naturally faster or slower as the weight changes.

 

Genius.

 

Thanks man.

Edited October 25, 2019 by RodBorza

[RodBorza]

;4086100']Yes sir.

 

 

Rocking up with min fuel and no payload will give you a much slower AoA speed than rocking up with the aircraft at the max landing weight loaded with fuel and weapons.

 

Yes. Now I get it. Thanks man.

 

P.S.: When will the new movie be coming up?