MAINTENANCE MINUTE By Scott Skola
BLUE LIGHT SPECIAL 3
String-aligning Bell 206 M/R blades can be a bit tedious. To help see the string better, fabricate a couple stringing mirrors. You can use pieces from a broken mirror or buy a couple small rectangular mirrors that will sit across the top of the M/R blade bolt. Carefully remove the reflective backing off the mirrors per the picture below. When aligning blades, center mirrors on blade bolts with clear area orientated chord-wise. While standing over the bolt, look down into the mirror and line up the actual string with its reflection. Check string position per CR&O. If the ceiling above the work area is dark, hold up a piece of light colored paper and position opposite your point-of-view to give a better background behind the string.
Ever need to remove something and the slide-hammer puller is MIA? Simply procure an appropriate threaded bolt and modify it with some safety wire as shown in picture below. If the item is a little stubborn, slip a ground handle wheel bar, other heavy wall tube, through wire and tap on loop until free.
The top mount nut on a Rolls Royce C20B FCU can be a bear, especially on the BO105 #1 engine. This “T” wrench is a concoction of a cut-off ¼” ignition wrench box-end, an MS20668 cable fork end fitting, and a couple old Bell 206 door latch rods. Cut the latch rods to make the “T” and weld them together along with the cable end fitting to fabricate the wrench. After cutting the ignition wrench, carefully drill a #40 hole in the remaining shank of the wrench. Insert box-end into cable fitting and rivet together ensuring the box-end still pivots. Reshape overall wrench to fit into the tightest of places.
Adjusting the idle screw on several different Rolls Royce 250 series engines while running can be challenging at times. Take the remaining open-end portion from the ¼” ignition wrench above and trim the shank to 1 ¼” total length. Drill a #40 hole as close to the wrench end as shown below. Add a second hole if you wish to upgrade it to the Adjustable Deluxe Model. Procure an 8” portion of 1/16” piano hinge rod and bond/swage an MS20667 cable eye end to one side. Fill a small syringe with 3M 2216 epoxy adhesive, or equivalent, and insert the other end of piano hinge rod into syringe until dry. Once released from the syringe, rivet the open-end wrench to cable eye end, ensuring open-end pivots. Bingo, idle adjustment tool. You may also need to grind off some wrench material to allow open-end to clear the FCU housing.
About the author: After 32 years maintaining helicopters in various capacities, Scott concluded a full-time career with a major operator in 2014. When not pursuing future writing projects, he can still be seen around the flight line tinkering on aircraft for beer money. He can be contacted at
tekaviationllc@gmail.com.
24 Mar/Apr 2019
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