Flight model question . Is it a bug ?

[colmbo]

With no torque as in counter rotating props . Aileron is still needed ? Thrust differential would not induce axial roll but rudder would in RL aircraft ?

Think about it.  The aircraft is pivoting about the vertical axis when doing a hammerhead.  The inboard wing is nearly motionless, the outboard wing is moving quickly….that causes an imbalance in lift…the outboard wing is making more (high speed) than the inboard..

I think the forward stick is to counter gyro precession…is that correct Hitech?

[Mongoose]

Me doing one in my RV.

http://www.youtube.com/watch?feature=player_detailpage&v=ulpdOHcCiNE

HiTech

  Ok, I gotta ask.  Is that you narrating? 

[hitech]

I think the forward stick is to counter gyro precession…is that correct Hitech?

That would be my guess, But I really never gave it much thought, has always been a move stick that way  plane does this. Learning hammer heads was one of the strangest things for me to learn, Want to end up on my back many times. Then once if finally clicked , it was automatic.

Now the only trouble I have is when my thumb occasionally hits the up trim button on the top of the stick (I really hate its placement on my rv) and on the down line I end up with my elbow in my gut pushing the stick ahead while running the trim back down during recovery.

There used to not be a retaining pin holding the aft stick in place, You could just pull it out, which I always did and stowed when flying solo. Bob Shaw and I were out playing when I first got the RV. At this time I did not have the inverted oil installed so negative G's would make a big mess of the plane. Anyway bobs doing a hammer head and on the down line I feel my self bumping the straps, I say to bob, "Bob your on the negative side" nothing but silence "Bob your on the negative side" nothing but silence "Bob I got the plane" and I recover from the down line  to vertical after which I say Bob what was that all about. Bob said "I'm sorry Dale, I was a little bit busy trying to shove the stick back in the hole".

HiTech

[bacon8tr]

  classic   

[hlbly]

Think about it.  The aircraft is pivoting about the vertical axis when doing a hammerhead.  The inboard wing is nearly motionless, the outboard wing is moving quickly….that causes an imbalance in lift…the outboard wing is making more (high speed) than the inboard..

I think the forward stick is to counter gyro precession…is that correct Hitech?

Colmbo I am trying to understand here . I am not being obtuse,well not intentionally. Why is there axial roll as soon as the rudder is input? Why is there no axial roll when thrust differential is used.At 40 ias I slightly back off the inside motor for a split second then go back to full. Stomp rudder to that side and she hammerheads perfectly , no axial roll at all? A stall turn exactly as described by aerobatic schools. I am not stupid just ignorant about this kind of stuff. I could teach for years about leadership and people skills to some around here and still not get them up to speed. When I use thrust differential the outside wing is moving faster than when I use rudders only. Why no axial roll then ?

[hotcoffe]

for those who are asking themselves `what the hell is a hammerhead?!`
From Wiki:
Hammerhead; Stall Turn    1/4 loop (pull or push) to vertical, as momentum/airspeed decreases, rudder is applied and the aircraft rotates around its yaw axis, the nose falls through the horizon and points towards the ground, a momentary pause is made to draw the vertical down line, and 1/4 loop to level flight. This figure is sometimes called a stall turn which is a misnomer because the aircraft never actually stalls. The manoeuvre is performed when the aeroplane decelerates through 20 - 30kts (more or less, depending on the aeroplane flown) of airspeed. The cartwheel portion of the hammerhead is performed with full rudder and full opposite aileron. Gyroscopic forces from the propeller during the rapid rate of yaw will produce a pitching and rolling moment and a degree of forward stick will be required to keep the aeroplane from coming off-line over the top. The yaw is stopped with opposite rudder while the ailerons and elevator remain in position, then once the yaw is stopped and the aeroplane is pointed down vertically, all controls are returned to neutral together. Although they can be flown left or right in any aeroplane with the proper technique, a hammerhead is best flown to the left with a clockwise rotating prop, and to the right with an anticlockwise rotating prop (as in a Yakovlev type), due to propeller torque/gyroscopic effects.