1/4ing head wind or down hill?

[MauleSkinner]

since ogden's slope is very minimal is one reason i sought to use the runway with the headwind. i'll be the first to admit i don't fly in the mountains a lot, maybe 50-100 hours, yes i calculated it both ways and the numbers worked. but when we took off we maybe had 20 feet over the departure end. granted the airplane we fly is 40 plus years old and might not still be able to do what the book claims. who said there was an argument with the captain, a mere discussion. avbug i never heard of a difficult or easy airport, just difficult pilots. avbug i'll show you mine if you shom me yours

Another question comes to mind...How did your takeoff technique compare to the technique used to determine AFM numbers? The mere fact that the airplane is 40+ years old shouldn't make a tremendous difference in performance, but it doesn't take a lot of difference in technique to throw book numbers out the window completely.

Fly safe!

David

 

[avbug]

Fly old planes...You gotta pay somewhere...hopefully not in a ditch somewhere.

Old airplanes?

I learned to fly in a 1947 J-3 Cub. It flew just as well when I learned in it as it did when it was new. I flew a 1944 PB4Y-2 into all sorts of places where performance really did become an issue (not nice flat runways)...and I don't believe for a minute that it lost it's performance over the years. Age is no excuse. If the airpalne is properly maintained, it performs. The airplane doesnt know how old it is. It knows about airflow, lift, etc...but unless your aircraft has been redesigned in the last few years, it's age is really quite irrelevant.

The numbers in your AFM pertained to the aircraft used to demonstrate the performance on a given day, followed largely by extrapolation and interpolation.

Your height over the end of the runway is really quite meaningless, unless ou have an obstacle with which to contend.

 

[gsrcrsx68]

That's a good point about the maitenance, but nobody I knew that flew that plane would agree with your point about the height over the end of the runway.

 

[avbug]

If you're not hitting something and you don't have obstacles with which to contend, then the height over the runway end is meaningless. A little like floating in the deep end of the pool. Who cares how deep the water is, if you stay on the surface? Who cares how much altitude you have at the end of the runway, if you're above the runway?

If your performance is inadequate, then consider yourself for the failure...the airplane didn't fail to gain altitude, you failed to ensure it was light enough to meet the performance standards you desired. The runway takeoff roll wasn't too long because the airplane was old...it was too long because the pilot failed to shorten it by reducing weight, waiting for a cooler day, taking off into the wind, or whatever needed to be done on a given day to meet the desired criteria. Including choosing a different airplane.

As far as height above the runway goes...I've had a heck of a lot of flights that broke ground and never climbed higher for the next hour or two, and I have a hard time getting too misty over not being able to climb at some preposterous rate. I've flown other airplanes in which I turned downwind at eighteen thousand feet, still in the traffic pattern...which is nice if that's what your mission requires on a given day. In a light piston engine airplane, clearly that kind of performance isn't going to happen. You might be used to five hundred feet per minute or a thousand feet per minute in a 172...this is a different airplane, loaded differently, flying differently, requiring different performance calculations, and must be operated accordingly.

Merely because others who have limited experience disagree about the height, is also meaningless...if I took them out for a thousand hours and worked them at six feet, they wouldn't think twice about it. The airplane isn't lacking. The experience of those making the observation is lacking, and it shows in their assessment and observation. When considering these things, keep that in mind.