Sunday Nov 19  2006

MGAS Filter tuning

Filter : C

Added an helical spring in parallel with the MGAS
Idea: Compress the MGAS to be slightly  negative and use the
helical spring to compensate.

Offset Mass: A1+B1+B2+B3+C1+D1+E2+F1+F2 

distance top surface base plate to top surface  safety plate: (105.1+-.1)mm
Mass Nut : (56+-1)g
Mass Bolt: (82+-1)g

There are two Cs with 90 degrees between the two  
Blade1 is on the left of the 'C' mark looking from the topview. Blades are numbered counterclockwise 

Helical spring length 153+34 = (187+-1)mm

Weight	Dt(s)	Periods	Frequ.(mHz)	Height(mm)	File	Comments
-	-	-	-		-		-	Blade 1 compressed  by 250um
2B	41.2	7	169.9		20.8		-	MISTAKE! CLAMP WASN'T TIGHT DOWN!
3B	42.2	8.5	201.4		18.0		-	-
-	-	-	-		-		-	Blade 5 compressed by 250um
2B+2N	64.0	11	171.9		-		-	-
-	-	-	-		-		-	Blade 6 compressed by 250um heard little bang found the three
								The three screws were not touching the clamp. It is quite
								probable (almost sure) the clamp went back. Measured 18.1mm
-	-	-	-		-		-	Blade 6 compressed by 250um
3B+1N	66.0	13.5	204		-		-	-
2B+1N	59.6	10.5	176.2		-		-	-
-	-	-	-		-		-	Blade 2 compressed by 250um
2B+1N	77.6	11	141.8		19.0		fit,psd,time
-	-	-	-		-		-	Blade 2 compressed by 250um
2B+1N	85.6	15	175.2		23		fit,psd,time
-	-	-	-		-		-	Blade 7 compressed by 250um
2B+3N	85.2	11	129.1		17.3		fit,psd,time

OBS: mode at about 1.2Hz is due to the pitching and rolling of the blades's tip connecting plate. 

Quality factor versus frequency: MGASC.Qvsf.pdf

pictures : dscn1178.jpg,dscn1179.jpg,dscn1180.jpg,