Slim , further to G`s input a few suggestions; if you can fly early morning, or late evening and preferably over flat terrain/sea, you will minimise any turbulence effects.If there is any wind, preferably constant with increasing height, then I always try to set it on a beam and do a climb, descend and do another on the reciprocal hdg.
It is most important to set the a/c up before your start height at the correct power and balance/trim, otherwise you may find yourself still fiddling about and not stable in the climb. Depending on the a/c`s ROC, that may be 500-1000 ft below your start alt.A good flt.test observer should assist with adjusting power as you climb to ensure you keep max. Most important if you are doing S/E climbs.
Some a/c altimeter systems are a little "sticky" and lag and if you are looking for s/e performance every foot or so of ROC is a bonus, so if you can ,get your FTE to borrow a "vibrator",or even a battery toothbrush and hold it against the panel near the altimeter you are using.
He could of course just keep tapping the panel, not the gauge,
but I think it has a slightly more professional nuance and he can use it as a good excuse, ie "flight-test equipment"!!
I say "he", but of course it may be otherwise !!
Further, if you can do two sets of climbs , one at high weight, and one at low weight, and take stabilised temperature readings at the mid-climb point you will minimise errors.
Smooth flying and minimal control inputs are the secret, ie if you are a couple of knots too fast or slow, don`t chase it, just maintain it as a steady speed..
Happy climbing !!
