Nose heavy on rotation?

[Corrigan]

Is it supposed to be this hard to pull up smoothly on take-off? Even with my extension on the warthog it's hard to pull up through the 13 degrees to the top of 3 degree poles smoothly. A few degrees nose up trim helps but I still end up with no give, and then suddenly going too far.

 

Thoughts?

[Pocket]

Is it supposed to be this hard to pull up smoothly on take-off? Even with my extension on the warthog it's hard to pull up through the 13 degrees to the top of 3 degree poles smoothly. A few degrees nose up trim helps but I still end up with no give, and then suddenly going too far.

 

Thoughts?

Takeoff pitch trim setting seems to have a big impact on rotation behaviour. Havent done any serious testing on it but thats the impression i get having practised more than 200 takeoffs and landings. I find that starting the pull back a couple of seconds before reaching rotation speed helps alot.

[Corrigan]

Am I really the only one that feels that the aircraft is a struggle to get off the ground smoothly?

[Pocket]

Am I really the only one that feels that the aircraft is a struggle to get off the ground smoothly?

 

Have you tried to start a pull back at around 250km/h and as it eases off on nose gear, gently easing the stick forward? I should add that 99% of my takeoffs so far has been with no payload or only x tank...

[outbaxx]

Am I really the only one that feels that the aircraft is a struggle to get off the ground smoothly?

 

 

No, I feel this too, it's impossible to start rotating before a certain speed, it's like elevons doesn't have authority before that speed. If you pull the stick full aft as soon as you start, nothing will happen until you suddenly have your nose looking at the sun :)

So to take off smoothly I need to apply pitch up after this speed. If I start pulling before I tend to pull too much.

[ac5]

Am I really the only one that feels that the aircraft is a struggle to get off the ground smoothly?

 

Same feeling here. Though, as reported by others, trim up helps.

[Corrigan]

No, I feel this too, it's impossible to start rotating before a certain speed, it's like elevons doesn't have authority before that speed. If you pull the stick full aft as soon as you start, nothing will happen until you suddenly have your nose looking at the sun :)

So to take off smoothly I need to apply pitch up after this speed. If I start pulling before I tend to pull too much.

 

This is wrong, then. Surface authority should turn-on smoothly with airspeed obviously.

[outbaxx]

Nose heavy on rotation?

 

This is wrong, then. Surface authority should turn-on smoothly with airspeed obviously.

 

 

 

You can always try to do a aerodynamic brake when landing:

-Softly raise nose to max alpha 16

-put nose wheel on ground at about 160kmph

- steer and wheel brake

- reverse if needed

 

Do it with a clean ac with less than 80% fuel.

[Pocket Sized]

This is wrong, then. Surface authority should turn-on smoothly with airspeed obviously.

 

If the main gear is far back on the aircraft (think naval planes, then remember how the Viggen is designed to be landed), the nose will be essentially unresponsive below rotation speed and extremely sensitive above rotation speed.

 

This is something the F-4 was absolutely notorious for. For a reasonable takeoff run you pulled the stick to the aft stop and waited until Vr, at which point the nose would shoot up without warning. You had to let the stick forward a considerable amount to avoid a tailstrike. So it's not unheard of. Just takes lots of practice to perfect.

Edited February 23, 2017 by Pocket Sized

[Corrigan]

Okay, well, fair enough. I should perhaps add that my experience is limited to simulated aircraft (and common sense + physics degrees). It's just that I've not seen anything mentioned in the SFI about this being an issue.

[outbaxx]

Doesn't the canard flaps create a nose up and that's why the elevons are dropped to counteract this? If so, when you give stick aft the canard flaps should make the nose go up?

Either way, with zone 3 you should according to the SFI be able to rotate at 190kmph, if you are low weight it is even less but the restriction is 190.

[Pocket Sized]

Yes, the flaps create a nose up moment. Without them, the nose would be even heavier during the takeoff run ;)

 

The current behavior is believable in my opinion but I have no idea if it's accurate to the Viggen.

[flo57100]

Set your trim to 5, and slightly pull the stick during take off roll to ease load on the nose gear. Your airplane will take off almost by itself !

Edited February 26, 2017 by flo57100

[Corrigan]

Okay, so I can see two issues here. First, the suddenness with which the plane is willing to rotate, which I can kinda see as plausible now as per Pocket Sized's post.

 

The second issue is that the plane does not rotate when it should according to the SFI, as outbaxx has found.