Factors Effecting Vmc - One big headache

[ryan1234]

this drag can be more than insignificant. an improperly trimmed old piper knock can knock 200 fpm off the climb. i've also noted that in transport aircraft, adding some trim in the flair greatly increases the tendency of the aircraft to float, whereas a flare done entirely with the elevators tends to make the aircraft settle right in.

it is drag, and it can be notable.

I'm not test pilot, but it would be cool to see some test evidence about that out of trim condition knocking 200fpm off the climb... with power and airspeed being constant.

Just seems like within the performance envelope of a Seminole, the trim tab would have the least effect on a climb rate, in terms of drag, etc.

I mean... if it is, I'm open to see some test proof.

As far as the whole trim makes an aircraft float - I'm not sure if that's an illusion or what.. but if you set the power, and have a certain deceleration rate - considering the reduction of induced drag in the ground effect... by the time you're at that large of an AOA - the drag effects of a trim tab seem nil at best... of course, if anyone has any proof - I'm absolutely open to hearing it as this is just my humble opinion.

 

[stratoduck]

mind you, i am not at all talking about cherokee/stabilator systems here - i am talking about the ragwing pipers that used a moveable horizontal stabilizer as the trim - the J-3 through the PA-22's.

when the aircraft is out of trim, you have two large surfaces generating a substantial amount of force (nose up or down) being counteracted by two large control surfaces.

no empirical data - just my observation flying these aircraft. it also makes logical sense that horizontal stabilizers that are not aerodynamically aligned with the elevators would generate more than negligible drag.