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Aircraft Moments of Inertia Analysis Report

Aircraft Moments of Inertia Analysis Report

Aircraft Moments of Inertia Analysis Report

(OP)
Dear All,

I looking for something guidance document on preparing a mass moments of inertia analysis report, that compares what changed between two different aircraft based on mass changes happened between them. Any tips or links please?

Thank you much...

RE: Aircraft Moments of Inertia Analysis Report

it's just "simple" data isn't it ?

you may get into trouble if you're changing payload and installed equipment, if you're trying to compare.

if commercial you need to consider partial payloads and people moving around the cabin, some call this the "potato" diagram.

You will need to be clear about what is accounted for where (under which heading) ...
Basic empty weight is a very basic airplane, often without an interior
Minimum flight weight has the minimum (duh!) added, like flight crew and unusable fuel and oil.
Operational empty weight would add the interior (including seats) and more crew and fuel reserves.
Max Zero Fuel weight (with is a type restriction) adds so much payload
Max take-off weight adds fuel

You need these weight distributions before you can calc mass moments.

You're modifying an existing plane ? you should be able to get the mass distributions for the unmodified plane and then calc the mass moment, and then your modified plane's masses and then mass moments.

Some more clues as to what you're doing (and why) would help.

another day in paradise, or is paradise one day closer ?

RE: Aircraft Moments of Inertia Analysis Report

(OP)
Thank you rb1957 Sir, but the mass moments are from the aircraft global CG?

Basically looking to compare before and after moments of a helicopter, and then somehow use the difference information to find effects on life limited parts.

RE: Aircraft Moments of Inertia Analysis Report

Society of Allied Weight Engineers [SAWE] may have useful information on this subject...

SAWE Introduction to Aircraft Weight Engineering
https://www.sawe.org/technical/publications/aircra...

SAWE RP-6, 1999: Standard Coordinate Systems for Reporting the Mass Properties of Flight Vehicles
https://www.sawe.org/technical/rp/sawe_rp-6_1999

SAWE RP-7, 2004: Mass Properties Management and Control for Military Aircraft
https://www.sawe.org/technical/rp/sawe_rp-7_2004

Regards, Wil Taylor

o Trust - But Verify!
o We believe to be true what we prefer to be true. [Unknown]
o For those who believe, no proof is required; for those who cannot believe, no proof is possible. [variation,Stuart Chase]
o Unfortunately, in science what You 'believe' is irrelevant. ["Orion", Homebuiltairplanes.com forum]

RE: Aircraft Moments of Inertia Analysis Report

Some data specific to a rotorcraft (Bell 412 / UH-1Y) can be found in this paper:
http://pubs.casi.ca/doi/pdf/10.5589/q02-021
(I only ever had the paper copy.)

No one believes the theory except the one who developed it. Everyone believes the experiment except the one who ran it.
STF

RE: Aircraft Moments of Inertia Analysis Report

"the mass moments are from the aircraft global CG" ...

yes, at the end of the day you want the mass moment about the CG, but to get there you sum masses and their moments about a datum point to determine the CG location. just like calculating the centroid of a section (1st and 2nd moment of area).

another day in paradise, or is paradise one day closer ?

RE: Aircraft Moments of Inertia Analysis Report

Also, may be useful...

SAWE-P-3020 MEASURING MASS PROPERTIES OF AIRCRAFT CONTROL SURFACES
https://www.space-electronics.com/contentAssets/Li...

ASD-TR-79-5004 Inertia Calculation Procedure for Preliminary Design
www.dtic.mil/dtic/tr/fulltext/u2/a072679.pdf






Regards, Wil Taylor

o Trust - But Verify!
o We believe to be true what we prefer to be true. [Unknown]
o For those who believe, no proof is required; for those who cannot believe, no proof is possible. [variation,Stuart Chase]
o Unfortunately, in science what You 'believe' is irrelevant. ["Orion", Homebuiltairplanes.com forum]

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