NoTechKnowledge Posted February 29, 2016 Report Share Posted February 29, 2016 Hey folks I'm middle of doing my cfi, and I cannot find any material that states how do manufacturers go about determining the reference datum point on a helicopter, particularly those that are outside of the aircraft, any help would be greatly appreciated thanks Quote Link to comment Share on other sites More sharing options...
iChris Posted March 1, 2016 Report Share Posted March 1, 2016 (edited) Hey folks I'm middle of doing my cfi, and I cannot find any material that states how do manufacturers go about determining the reference datum point on a helicopter, particularly those that are outside of the aircraft, any help would be greatly appreciated thanks The helicopter’s datum is established by the manufacturer as required under §27.1589 or §29.1589; however, its location is purely the choice of the manufacturer to describe and illustrate. Once the datum has been selected, all moment arms and the location of CG range are measured from that point. As a general rule, most manufactures place the datum forward of the nose. As a result, all values are positive when calculating the longitudinal CG. The datum is referenced from some point on the helicopter, as an example, the main rotor centerline. You can refer to the references below for more information: § 27.1589 LOADING INFORMATION Explanation. Control of the rotorcraft weight and balance is an operationalfunction and is the responsibility of the operator. However, instructions necessary toenable loading of the rotorcraft within the established limits of weight and center ofgravity and to maintain the loading within such limits are required by the operatingregulations, and inclusion of such loading instructions in the Rotorcraft Flight Manual isrequired by this rule. Approved loading instructions, therefore, must be presented in theRotorcraft Flight Manual and, at the option of the applicant, may be included in theapproved portion or in the unapproved portion. (iii) Dimensions and Datum Line Locations. The dimensions and relativelocation of rotorcraft features associated with weighing and loading of the rotorcraft andwith weight and balance computations should be described and/or illustrated…. Pg. G-48.2 – G-49AC 27-1B - Certification of Normal Category Rotorcraft Edited March 1, 2016 by iChris Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.