B. Bland, J. Kissel, T. Sadecki

Before we started the second round of testing, Betsy and Travis, under the advice of Joe O'Dell, wanted to make an adjustment to the blade spring tip heights of the M1 mass on BSFM01. Here was the story up to this point:
- Initial transfer functions showed several resonances much higher than expected, which implied the M1 suspension points ("d's") were off, and that therefore the M1 blade spring tips were too high. 
- The tips were then lowered a little bit (about ~mm), and no effect was observed.
- The tips were then lowered a good deal (several mm), which finally showed results where resonances were returning to the expected values. However, the tip lowering was done qualitatively so it was unclear exactly how far the tips had been lowered. Further, this caused the remainder of the chain to be significantly lower than modeled.
- BSFM01 was taken down (to be replaced by a QUAD).

However -- the story is little bit more complicated that this (see attached .pdf that demonstrates the story): The blade tip is ideally flat, from base to tip. However, because of the short geometry of these blades, (which, when unloaded, are highly curved) they are in reality a little bit curved up at the tip. Further, the procedure up to this point had been to physically measure the type height from a location that was *not exactly* at the blade tip, using gauge blocks placed physically on the blades (see E1000686). If the tip curves up *further past* the measurement point, then it is not representative of the actual tip height. Finally, though the gauge block as little mass, one still might imagine its presence on the blade spring influencing the measurement.

Now that BSFM01 was back up on the Assembly Test Stand, the plan of attack is two-fold. Re-adjust the blade tip heights back to the nominal height, but using a different reference point for measurement: a gauge block resting on the M1 base plate (with M1 locked down in its nominal position), exactly in front of the blade tip suspension point (again, see attachment). According to Joe's calculation, the distance between the the M1 base plate and M1 blade spring tip, with the suspension is under load and free, should be 26.6 mm.

The adjustment has been done; all four blade tips have been adjusted to have this height with respect to the M1 base plate. 

Now on to measurements, to see whether the results are promising!