Aborted Takeoff

[NC_BE300]

I have aborted a T/O in a C150. On this airplane (built in 1974), the pitot tube has a metal flap attached to the assembly. During T/O roll, when the speed is great enough, the airflow over the tube fits the top part of the flap, and opens up the pitot tube. After advancing the power, checking the instruments, etc, it wasn't long before the C150 was ready to lift off because I was at a low T/O weight. I could feel the airplane wanting to fly, a quick check of the airspeed revealed ZERO. Pulled the power to idle, advised the tower, and taxiied back for another try, just in case the metal flap was stuck on that run. During the second try, I watched the metal flap on the wing during T/O roll, and sure enough, it wouldn't come off the pitot tube. I then aborted again, taxiied in, and removed the metal flap attachment myself from the pitot tube (which was only attached by what looked like a bobby pin). After that, everything was fine.

 

[sixpack]

WHOOOOOAH!

[ QUOTE ]
I would close the fuel selector on the 152 when we took position on the runway. This would result in the engine quitting at about 30 knots on the takeoff roll ... it always caught my students by surprise. Good object lesson in being prepared for anything on takeoff (or any other time).
FL270

[/ QUOTE ]
Not sure this such a good idea.
#1, you might shutdown the runway if you can't get the engine restarted soon.
#2, what if the selector is slow to kill the engine.. say kills it at 60 kts instead of 30kts?

 

[FL270]

1. It was a non-towered airport, and I only did this when traffic conditions permitted.

2. Whenever I did this, if the engine didn't quit by 40 knots, I would reject the takeoff by retarding the throttle. I never had to do it, though.

I did not do this without giving it the necessary consideration, rest assured.

FL270

 

[pilotjww]

The Mountain Flying Bible by Sparky Imeson includes a Rule of Thumb that says:
"If 70.7% of the speed necessary for rotation is obtained at the halfway point of a runway, you can take off in the remaining distance. If not, abort the takeoff."

 

[sixpack]

[ QUOTE ]
The Mountain Flying Bible by Sparky Imeson includes a Rule of Thumb that says:
"If 70.7% of the speed necessary for rotation is obtained at the halfway point of a runway, you can take off in the remaining distance. If not, abort the takeoff."

[/ QUOTE ]

That's 1 over the square root of two. Is assumes a lot of things, like constant acceleration. Personally, I'd add some fudge factor.

 

[Mavmb]

Anybody ever get tired of the pretakeoff briefing? Sometimes I just want to add at the end, "And if we have a meteor come out of the sky and hit our plane after rotation, we shall kiss our asses goodbye."