ANDY bush

[df54]

In one of his articles andy bush talks about a hi-g roll over and hi-g roll under. Sounds to me like he's talking about lag rolls tho his terminology is different. Am i correct?

[SlapShot]

These are what he considers "Last Ditch" defense efforts to shake a bandit from your tail. They are an "attempt to force an abrupt role reversal through a severe change in closure and/or angle off."

I wouldn't consider either of these maneuvers to be "lag" in the sense of the word.

His drawn example of the "High g Roll Underneath" is nothing like I have ever seen before. His drawn example of the "High g Roll Over The Top" looks very similar to a barrel-roll but from his description ... it's more than just a barrel-roll.

The article is here ...

http://www.simhq.com/_air/air_023a.html

Edit ... Andy Bush is the "real deal" ... reading and applying what he writes ... you can't really go wrong. When I first joined AH I read ALL his articles. He use to participate on this board, but I haven't seen him post in quite some time which is a shame.

[Andy Bush]

Originally posted by df54
In one of his articles andy bush talks about a hi-g roll over and hi-g roll under. Sounds to me like he's talking about lag rolls tho his terminology is different. Am i correct?

Hi guys!

I'm still around...just not seeing a lot of action these days.

DF...

As Slapshot said, these maneuvers are 'last ditch' defenses to a close in, 6 o'clock gun attack.

They are not in any sense a 'lag roll'.

Either maneuver (over the top or underneath) is an extreme application of controls that produces a very high angle of attack combined with a roll. The end result is the aircraft 'flat-plating and rotating about its longitudinal axis. The drag produced is very high and leads to a significant speed loss. This speed loss is the objective and is what causes the attacker to likely overshoot from his 6 to a 12 o'clock position.

Not all aircraft can perform this maneuver. Only aircraft that have a good amount of rudder authority are capable of this maneuver. Swept wing fighters with relatively large rudders are best suited to this maneuver.

The maneuver would be entered from a hard defensive turn. The pilot then increases g towards the buffet point as he feeds in full rudder. In a right turn, the left rudder produces a roll that causes the plane to rotate left...consequently the name 'over the top'. If the right rudder is used, the plane rolls further to the right, goes inverted, and then comes back out to its original position...hence, 'underneath'.

These maneuvers are very disorienting for the pilot flying them and leave him pretty much dead in the water. If the attacker wasn't forced into an overshoot, the defender is in serious trouble.

Hope that helps.

[FLS]

Originally posted by Andy Bush
Hi guys!

I'm still around...just not seeing a lot of action these days.

May I recommend candy and/or liquor?  



Happy Holidays!

[df54]

playing around with hi and lo g rollover. Am i suppossed to snap roll.
  Will post film for analysis shortly

[Andy Bush]

Read more about this maneuver here:

http://www.aviation-history.com/airmen/boyd.htm

[FLS]

Boyd seems to have been the model for Maverick in Top Gun.  

df54 that would be a "no" on the snap roll.

[Andy Bush]

DF...

A 'snap roll' is an aerobatic maneuver...not BFM.

In a High G Roll, the fighter is not usually stalled...although that might happen in some cases. Normally, the AOA is approaching the stall when the rudder is applied and the aileron held in (or reversed).

[SlapShot]

Ahhh ... there he is !!! ... good to see that you are still around Andy.

[Krusty]

Does anybody have an AH film of this in use? I *think* I get the idea, you rudder roll 180 degrees so you're going in butt-first, like a space shuttle slowing down. I just don't quite grasp how you pull it off.

[NoQtr]

yes, I would love to see this move on film.

[BaldEagl]

Originally posted by Andy Bush
Read more about this maneuver here:

http://www.aviation-history.com/airmen/boyd.htm

I can see where that would work in a jet fighter but can a prop driven WWII fighter actually pull that off?  It just doesn't seem like there would be enough E to pull it off.

[FLS]

Originally posted by BaldEagl
I can see where that would work in a jet fighter but can a prop driven WWII fighter actually pull that off?  It just doesn't seem like there would be enough E to pull it off.

As Andy stated in the article that Slapshot linked, if you're low E go low. You go up when you have the E to go up.

The Boyd maneuver is a little different because he's in an F100 and can't use the full aileron deflection that Andy recommends.

[Andy Bush]

Originally posted by BaldEagl
I can see where that would work in a jet fighter but can a prop driven WWII fighter actually pull that off?  It just doesn't seem like there would be enough E to pull it off.

The problem isn't one of energy...it's one of aerodynamics.

Swept wing fighters experience something called 'dihedral effect' when yawed at high angles of attack. Straight winged fighters may not experience the effect to the same degree.

The outcome is that yaw combined with high AOA produces a strong rolling force. This roll can be induced by rudder application alone...in other words, high AOA + yaw = roll.

Along with this roll comes a ton of drag...and this drag produces an exaggerated energy bleed off...much greater than just pulling the throttle to idle and/or extending the speed brake.

It is this speed loss that causes the attacker to overshoot...the attacker is surprised and cannot slow down fast enough himself. As a result, he flys past the defender and ends up 'out front'. Now, he's the defender.

Is there a counter to this maneuver? Yes...depending on the severity of the attacker's closure, either a High Yo-Yo or a Quarterplane will preserve his offensive position.

This maneuver does not have to flown with rudder only. Ailerons may be used along with the rudder, particularly in straight wing fighters.  In Boyd's case (the F-100), he did not use aileron because of the swept wing problem with adverse yaw...aileron deflection would create additional yaw that tended to result in the fighter departing controlled flight. The High G Roll may be abrupt, but it is still controlled.

[Traveler]

Originally posted by Andy Bush
Hi guys!

I'm still around...just not seeing a lot of action these days.

DF...

As Slapshot said, these maneuvers are 'last ditch' defenses to a close in, 6 o'clock gun attack.

They are not in any sense a 'lag roll'.

Either maneuver (over the top or underneath) is an extreme application of controls that produces a very high angle of attack combined with a roll. The end result is the aircraft 'flat-plating and rotating about its longitudinal axis. The drag produced is very high and leads to a significant speed loss. This speed loss is the objective and is what causes the attacker to likely overshoot from his 6 to a 12 o'clock position.

Not all aircraft can perform this maneuver. Only aircraft that have a good amount of rudder authority are capable of this maneuver. Swept wing fighters with relatively large rudders are best suited to this maneuver.

The maneuver would be entered from a hard defensive turn. The pilot then increases g towards the buffet point as he feeds in full rudder. In a right turn, the left rudder produces a roll that causes the plane to rotate left...consequently the name 'over the top'. If the right rudder is used, the plane rolls further to the right, goes inverted, and then comes back out to its original position...hence, 'underneath'.

These maneuvers are very disorienting for the pilot flying them and leave him pretty much dead in the water. If the attacker wasn't forced into an overshoot, the defender is in serious trouble.

Hope that helps.

Not a lot of help in this sim, only two swept wing aircraft and they have little tiny rudders.   But always enjoy your stuff. thanks