An Interesting Merge

[jerkins]

I saw no yaw until an indicated air speed  of 16 MPH. That is why I questioned the aircraft model. 

At this point, the aircraft is simply yawing due to gravity creating a moment on the airplane. I can draw up a diagram later.

[Traveler]

At this point, the aircraft is simply yawing due to gravity creating a moment on the airplane. I can draw up a diagram later.

 My point is that between 75mph and 16mph the aircraft shows no loss of directional control due to yaw and it should have.

[mechanic]

 Directional control was not really an issue, i thought. As jerkins says, he set-up the turn long before 16mph knowing that gravity and engine power would combine to complete the turn almost without further input. All that is required is a little after touch to stop a drastic stall and set the aircraft up to regain speed and regain control whilst still in a good angle of attack.
 Sure its a game and nothing in a game is perfect. But if you think that is a little suspect you should really worry more about something like the F4u Corsair when it comes to suspect stall handling.
 Personaly (without any real life experience in these birds) I think the flight model of AH2 would be the thing to tweak, not the mossy specificaly. yet i don't think it is too far off from reality.

[Traveler]

Directional control was not really an issue, i thought. As jerkins says, he set-up the turn long before 16mph knowing that gravity and engine power would combine to complete the turn almost without further input. All that is required is a little after touch to stop a drastic stall and set the aircraft up to regain speed and regain control whilst still in a good angle of attack.
 Sure its a game and nothing in a game is perfect. But if you think that is a little suspect you should really worry more about something like the F4u Corsair when it comes to suspect stall handling.
 Personaly (without any real life experience in these birds) I think the flight model of AH2 would be the thing to tweak, not the mossy specificaly. yet i don't think it is too far off from reality.

I don't know if flight models are specific to the game or each aircraft within the game.  My point was about the flight model as applied to the mossy in the specific video provided, I questioned how with power applied and the airspeed between 16 and 75mph, the mossy should not have been able to matain directional control with the rudder. I said nothing about stalls. as far as I know the AOA was within limits during the zoom up.  But the rudder at such low airspeed would have no effect on Yaw.  With power applie, Pfactor would be overwhelming.  Just do a take off in a Mossy without applying rudder with airspeed between 16 and 75MPH and see how far off the runway you end up.

After rechecking the video, it appear that WEP was applied during most of this flight.  That would produce a very large PFactor.

[mechanic]

Thats what i am trying to explain to you, the turn was set up at a time when rudder authority was much higher.

Like throwing a ball into a bucket, you set up the power, angle and apex then gravity does the rest for you without additional input. Jerkins threw the ball up at the right angle then caught it on the way back down before it landed in the bucket.

As for low speeds and rudder on the runway, the rudder counters the torque at 16mph on the runway, so why not in the air at similar speeds?

[dedalos]

As for low speeds and rudder on the runway, the rudder counters the torque at 16mph on the runway, so why not in the air at similar speeds?

 

[mechanic]

yeah i know, there is less ground stopping it roll. But i dont understand why even at 16mph the rudder should have 0% authority in the air.

[Traveler]

Thats what i am trying to explain to you, the turn was set up at a time when rudder authority was much higher.

Like throwing a ball into a bucket, you set up the power, angle and apex then gravity does the rest for you without additional input. Jerkins threw the ball up at the right angle then caught it on the way back down before it landed in the bucket.

As for low speeds and rudder on the runway, the rudder counters the torque at 16mph on the runway, so why not in the air at similar speeds?

No the rudder does not counter the tourque at 16mph on the runway, the weight of the aircraft on it's gear and the pilot  breaking against the tourque induced turn to the left by stearing to the right.  The linkage between tail wheel and rudder ensure that two (Rudder and differential breaking work together until the minimun airspeed is reached that the rudder becomes effective.  The tail can be raised at that airspeed.  The pilot knows that airspeed as it's is the lowest airspeed listed on the airspeed indicator.    In the case of the mossy, that's 40 mph.

Someone will have to explain to me how a pilot can set up a turn ahead of time?  Ailerons, elevator and rudder can be prepositioned now to  become effective later?  Not sure I follow that.  Not with the engine set at WEP and no effective rudder to counter the tourque.

I just flew a mossy with WEP on and below 40 mph in the air, you can't control the Yaw (tourgue). On the gound below 40 mph you stear to the right, hold right rudder.  until you reach 40, lift the tail and the aircraft rudder is effective enough to conter the tourgue even with WEP on.  What I didn't understand from the video was that the mossy with WEP at an airspeed below 40 did not show signs of Yaw until 16 MPS, what happened betwee 17 and 40?  In other words at 39MPH there should have been signs of a yaw as the rudder lost it's effectiveness.

My father, who flew P47's and P51's in WWII, told me about the lowest number on the airspeed indicator being the airspeed at which the rudder becomes effective.   He taught me to fly in a J3 and T6 some 45 years ago. 

 

[mechanic]

 Did you not hear jerkins playing with the throttle at all? He wasnt on wep the whole time and showed a good knoledge of throttle work which enabled the turn at all. Many people trying to replicate his move here will find themself falling backwards and losing the fight. I meant if you lock the tail wheel, you still have a very slight ammount of rudder control.
 
 Throwing the ball up does not require control input to make it come back down, right? So that is the essance of a stall turn, if you initiate the turn correctly gravity takes over for the moments when control surfaces are ineffective and setup well enough the move appears seamless despite the fact that some moments were totaly out of the players hands.

 I ask from an uneducated standpoint, are you telling me that below the lowest indicated airspeed the rudder simply does not work at all, or are you confusing the term 'effective' with 'not at all'? I am not trying to be a wise guy, i honestly dont know the answer.

[jerkins]

I think i may have some input on the situation from a dynamics perspective.

We will look at the plane the moment just before stall, so the momentum of the plane can be disregarded due to the low speed. We also will not look at the engine torque due to the fact that this causes rotation about the roll axis, not the yaw axis.  The reason rudder helps or hinders roll is do a moment created from the rudder being out of line with the CG.  This is another topic.







In this case I set the plane up with the right trajectory to let gravity do all the work for me.  It is what allowed the plane to yaw so quickly (similar to hammerhead)

The affect of this yaw can be reduced if the plane were in a steeper trajectory, notice that the start of the stall in nearly vertical, however, slight slanted left.  This means that at this point nearly all thrust produce be the engines is canceled out by the force of gravity, with a very minimal horizontal force.  Low horizontal force means, low moment produced, therefore, minimal yaw.  As the yaw angle from vertical is increased, the horizontal thrust increases, leading to more yaw.

[Traveler]

Did you not hear jerkins playing with the throttle at all? He wasnt on wep the whole time and showed a good knoledge of throttle work which enabled the turn at all. Many people trying to replicate his move here will find themself falling backwards and losing the fight. I meant if you lock the tail wheel, you still have a very slight ammount of rudder control.
 
 Throwing the ball up does not require control input to make it come back down, right? So that is the essance of a stall turn, if you initiate the turn correctly gravity takes over for the moments when control surfaces are ineffective and setup well enough the move appears seamless despite the fact that some moments were totaly out of the players hands.

 I ask from an uneducated standpoint, are you telling me that below the lowest indicated airspeed the rudder simply does not work at all, or are you confusing the term 'effective' with 'not at all'? I am not trying to be a wise guy, i honestly dont know the answer.

Yes, look at the video but stay in the cockpit and watch the rpm and boost,  He is in WEP for 95% of the fight.  he is in WEP during the zoom.  Look at the gages.

[Traveler]

This is another topic.

 
and that's the topic that I am refering to.  during the zoom when airspeed gets very low, below 40mph, There is not enough rudder authority to prevent yaw.  I was suprised to see that no YAW was induced until the airspeed was decreased to 16MPH.  The engins were in WEP.  I question the model.  There is no way that YAW would not have been present due to PFactor and Gyroscopic progression. 

[jerkins]

Yaw was present, I was fighting it the whole time, and then in the end, I reduce throttle, the cut it completely.

You can think of it like pre-loading the controls, and setting yourself up to let the plane, yaw and roll into a position that leads your advantage.  The the mossy  up and get some airspeed, say 250mph.  Put the mossy into the vertical make it stall straight up, and then fall backwards back to the earth.

Once you can do that, gather airspeed again and climb vertical, now try to time your inputs so that you can achieve a similar stall to what the video shows.  Too early on the inputs, your flight path become a large turn.  Too late in the inputs, you tumble to the ground.

Try letting your airspeed get down to about 100mph, and then kick rudder until your nose it at about 10 or 11 o'clock.  As soon as you reach this yaw angle, cut throttle, but hold your rudder and aileron where they are.  With practice you can do it.

 
 I was suprised to see that no YAW was induced until the airspeed was decreased to 16MPH.  The engins were in WEP.  I question the model.  There is no way that YAW would not have been present due to PFactor and Gyroscopic progression. 

As I tried to show in my diagrams, the rudder did not cause the yaw at 16mph, that yaw was induced by the factors mentioned in your statement.

[mechanic]

so the truth really is it was an interesting stall turn, and a pretty standard E merge

[Tr1gg22]

I thought it was a good merge