Rotax propeller, moment of inertia

bones

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Ok smart people, need some help here how would one work out how heavy of a propeller can i swing on a 914, reading out of the manual(cant believe i looked at it) it says the following;
Momentent of inertia for propeller;;; 6000 kgcm2, that is of course SQUARED.

So if i am using a 70in prop, how much weight can i swing around with out damaging anything?

The reason i ask is because i am trying a neat little trick for prerotator, only thing is i had to use a steel pulley on prop hub, and its damn heavy, took it back to the shop to put it on a diet, but i was wondering how do i work this out?
70in is 178cm

No idea if i am even starting this right.
What i did was 89x 3.1412= 280cm2, then divided that by 6000
I worked out to be about 46kg, but dont know if im right or not??????
 
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birdy

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The distance from the hub needs to be pondered too, just to keep the pressure on them miserable grey cells you have. ;)
If the extra weight is close, it wouldnt make much difference, but i know the 68" IVO iv got on the wasa is MUCH heavier in inertia than the old 72" WD.
Makes for smoother starts n stops, but it makes peddle stomp responce very lame.
 

bones

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So the 70" ivo med i got with this damn pulley gonna really suck then huh
 

birdy

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Duno, how much beefyer than a WD is the ivo med?

I dont think you gota wurry bout the pully, its radius is too small to hinder much.
 

bones

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Well the pulley only ended up 3.5kg so its not a prob now, so all i got to do is put it together, and wait for this this f**king rain to leave, so i can try it, ohh nd birdy that other yellow machine is going home tomorrow :( damn nice bit of gear now(now that it actuallly f*cking finished), just need to work out the efi bit better and sweeeeeet
 

birdy

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That didnt take long.

So ol mates a happy chappy now then?
 
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