The blade grips on the Synergy E5 are larger that the blade grips of most 500 - 550 sized helicopters. The measurement between the blade grip arms is 14mm (or pretty close). The blade root on the Rail 556 blades is 12mm, four 1mm shims with 4mm holes are required for proper mounting, one shim on the top and bottom of each blade root.
Do not attempt to squeeze the blade grips together using the blade retaining bolt (or any other method) in order remove the extra space and forgo the use of spacers. The result of doing so will be unpleasant at best and could result in the destruction of your helicopter and or injury to you or others. Spacers are not included with Rail 556 blades nor are they included with most other manufactures blades under 600mm. The reason for this is because most 500 class helicopters have blade grips that are 12mm (10mm in some cases) and therefore spacers are not needed. The Synergy E5 was designed to be configurable, and in anticipation of pilots wanting to stretch the boom and run larger blades a more robust head was included as standard equipment. Other manufactures sell upgraded heads for their 500 class machines for $60 or more to allow their helicopters to swing larger blades, on the E5 the upgrade is standard. A $1.99 set of shims are required if you are using blades with roots less than 14mm. This seems like a pretty good deal to me so don't forget to order your shims. Another course of action would be to purchase a E7 kit and a set of Rail 696 blades. You could then use the 1mm spacers from the 696 blades for your E5.
Rich
