I will publish a service alert later today on the website (www.rotaryaviation.com) on B drives used on turbo charged 13Bs and 20B engines. 

 

Decided to do this after reviewing Steve Brooks input shaft problem.  His input shaft was previously used for well over 100 hours on Ed Anderson's drive (fairly early drive) with no problems.  It used the welded style sun gear attachment to the input shaft.  Steve's turbo engine apparently had enough torque to break the weld in the same way that Dave Leonard's (another turbo) did. 

 

Shortly before starting C drive production (4-23-03)  we changed over to a drilled and pinned input shaft.  This service alert requests (strongly) that any B drive used on a turbo charged 13B or 20B engine delivered before this date be inspected for presence of a pinned input shaft.  If the sun gear is welded instead of pinned, the input shaft should be returned to RWS to have it drilled and pinned prior to any flight.  This service will be performed for only the cost of materials and shipping.  No problems have been encountered on RD-1, RD-1A or RD-1B drives used on normally aspirated engines but if you wish, this update can be done for a nominal service charge ( parts & shipping + shop time TBD).

 

 

Rusty was asking the dimensions and durometer of the rubber dampers in the drive.  I think the question was aiming to change durometer in order to change the resonant frequency on his one rotor installation.  The diameter of dampers is 1.374" and durometer is currently 50.  I don't think changing this will significantly change the fundamental (lowest order) resonance that occurs at low speed (idle area).  This is primarily affected by the system lash.  The dampers significantly affect only higher order harmonics which can't often be felt but can be very destructive to the drive train. 

 

Bottom line is I think it would be a wasted effort to change the rubber dampers.

 

Tracy