BRP Rotax has introduced Generator Flange Part No. 953978. SI-PAC-023 explains drive flange integration and maximum torque i.e, 116 Nm at takeoff rpm. However, I think that SI-PAC-023 does not fulfill all the requirements for proper integration of optional accessories with drive flange. 

For example, Can I install belt driven external generator/alternator of 500W. If yes, then I have to install driver pulley on the generator flange. If I install driver pulley on generator flange, then there will be bending load on generator flange due to belt tension. So, there must be some limit of maximum driver pulley length and allowable bending load on generator flange which rotax has not provided in the SI-PAC-023 or any other document.

SI-PAC-023 is attached.


10165_1_SI-PAC-023_Optional accessory drive flange for ROTAX Aircraft Engines.pdf (You do not have access to download this file.)
  • Re: Optional Accessories Integration Requirements on Drive Flange - SI-PAC-023

    by » 7 months ago

    Hi Shoaib

    Thats a good question.  Your regional distributor is:

    Luciano Sorlini S.p.a.
    Via G. Marconi, 33
    25080 Carzago Riviera, Italy
    I would request they try to get you an answer.  I have never seen any such data before and am familiar with some engines using up to 5 KW off the crankshaft end with the 914 engines.  The drive end for the 915 is much better supported and i would guess that the side load should not be that much with only a 500 W generator.  You can send in a customer information report, request,  via the distributor and they should find out if there is any information and report back.

  • Re: Optional Accessories Integration Requirements on Drive Flange - SI-PAC-023

    by » 7 months ago

    Hi Wizard,

    Thank you for the reply. Actually, this is my old account almost 10 years old. I am now in KSA. I floated my question thinking that may be some have expert opinion about this topic on the forum. 

    About the question, I would say that 116Nm torque is a big number. It's almost 70kW at takeoff rpm. There will be no problem, if you are going to couple something directly to flange drive, but if you are going to have belt driven system you must know the bending load limit for crankshaft and drive flange.

    Even in case of gear box flange there is a limit for propeller extension block/spacer. 

    Let me check authorize distributor for KSA. 


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