G109 Operations Startup and Taxi
First thing is start up procedure. The throttle should be “cracked.” This is aviation talk for merely a little bit of throttle. Not a lot, or the engine will rev too high on starting which is deadly for a cold engine with no oil flow. Begin with just a little throttle and when the engine starts, SLOWLY increase RPM to 1500. Get the FEEL of the engine.
Don’t start to taxi until the engine has warmed up for a while. I have observed punters blasting off after only a couple of minutes. It shouldn’t require takeoff power to start rolling towards the runway unless the tail wheel is sideways. Finesse, rather than brute force and ignorance is what it is required.
Taxiing is challenging for some people. The Grob has a full swiveling tail wheel. There is a weak detent to lock it in place, which may work on a paved surface or a German grass strip which is maintained like a bowling green, but on our sheep paddock is not sufficient to keep the aircraft straight. When one wheel hits a hole or soft spot and slows down the airplane wants to turn in that direction. The rudder pedals have to be in constant motion from side to side with no hesitation in the middle. The Grob will not go in a straight line for any length of time on a rough field with the pedals centered. But it is actually quite easy to steer once you get used to it.
With individual brakes on each pedal, it is possible to spin the plane around in a small place. This requires a great deal of situational awareness. This works OK on HARD ground or pavement. Unfortunately, we don’t have a lot of that. On soft ground, two things happen. 1. The stationary wheel augers into the earth. 2. The tail wheel turns sideways. With the main gear bogged and the tailwheel sideways, full take off power won’t move the plane. Make the radius of the turn wide and straighten the tail wheel by moving ahead after the turn. Soft ground can be a trap for any plane. Ian tells of a Ximango which suffered landing gear damage from a sharp turn on the ground. Of course, the Grob gear is far stronger, but there is still a lesson there.