Real World Solutions, Inc
Home of RA Classic Apex Seals and RA Super Seals
|
How to Lighten the RD-1x Series of Gear DrivesSeveral builders have expressed a desire to lighten the RD-1A/B drive. The most obvious place to do this is the adapter plate but the correct way to do this is not so clear cut. Even though the 1/2" plate looks like a lot of weight, the standard adapter plate weighs 7 3/4 pounds, not a lot for the job it is doing. Shown below (upper left) is one example of a custom adapter plate that the builder fabricated to incorporate a couple of engine mount points. Since this increased the weight of the plate, he decided to reduce it a bit by milling out some pockets where it would not be detrimental. When looked at from the standpoint of stress imposed by engine weight and G forces in flight, this is a perfectly adequate way to reduce the weight since the plate is essentially a deep truss structure. But when looked at from the standpoint of gyroscopic forces imposed on the plate when the airplane is changing pitch, the forces on the plate are in bending mode. In this case, the strength is reduced considerably. It is difficult to determine exactly what the strength requirements are in this mode but I would be reluctant to reduce it in this way. My concern is not that the plate might break but when the plate flexes, the drive line is bent out of line and the consequences of this are not predictable without a lot of testing. Shown below (top right) is the standard RD-1A/B adapter plate. If you would like to lighten it, the only "Factory Approved" method is shown below (bottom right). This method removes metal where the stresses are minimal. Total weight reduction is about 1.5 pounds. Only the aircraft builder can decide if the reduction is worth the effort. I'm a bit of a 'weight freak' so I made the change on the RVotter.
|
|
Send mail to
laura@rotaryaviation.com with
questions or comments about this web site. |
