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A solution to a Cof G problem on a Bristell NG5 is to install 5kg of ballast as for forward as possible.

There is a convenient place behind the gearbox on a 912iS.

Has anybody ever had to fit ballast, or have fitted ballast to the engine on a 912iS

 

  • Re: Installing ballast 912iS

    by » 4 years ago


    5kg is 11lbs!

    We have not seen anyone place this kind of weight behind the gearbox of a Rotax before and have no idea what kind of issues would come from it. Can the engine mount allow for that amount of additional weight?  This is something you would need to discuss with Bristell about 100%

     


  • Re: Installing ballast 912iS

    by » 4 years ago


    There is an issue with the Bristell W&B in the UK. The 912is is about 7kg heavier than the ULS and is less likely to have an issue.

    Regards,

     

    John


  • Re: Installing ballast 912iS

    by » 4 years ago


    The engine is a 912iS. The aircraft is a taildragger. The LAA have moved the pilot CofG aft by 150mm. I.e greater than the range of Cof G. The obvious solution is to move the seat forward by 150mm. ( Yes there is room for an average body). But the LAA have refused.


  • Re: Installing ballast 912iS

    by » 11 months ago


    It may be late, but at OSHKOSH this year, the demo Bristell had 9.5kg ballast installed in 2 weights; one on the top of the gearbox and one underneath on the forward engine mount. Certification in the USA is obviously easier than in UK!


  • Re: Installing ballast 912iS

    by » 10 months ago


    Hi Trevor

    Just to be clear we need to understand that the Bristell is flying without being certified in the USA under part 23.  They are flying under a special airworthiness for light sport aircraft built to the ASTM standards.  The OEM, Bristell in this case, self declares that they meet those design standards and the FAA has an inspection done, usually by a DAR, to check the paperwork to issue the airworthiness.  Apparently it is different in the UK where the government allows LAA to change such declarations?  It sounds like the LAA disagrees with the design weight and balance, perhaps they have found something wrong with the calculations?  In any event it looks like Bristell should work with LAA to resolve this.  

    I am unaware of any issues of weight and balance with the Bristell.  To be fair very few are taildragger and that might be the problem.  Normally a taildragger the main gear is forward of the position of a trike configuration to address that.  Adding weight is not really a good solution unless it has been approved by the OEM. 

    Cheers


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