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Hi friends,

We have 2 Super Dimona HK 36TC, one fitted with 912A3 and the other 912S3. It has been observed that Rotax 912 A3 and Rotax 912 S3 engines are non interchangeable. That is the aircraft which is meant for 912 A3 cannot be installed with 912 S3 and vice versa.

We want to convert A3 engine to S3. We know there are many parts like cylinder/piston set, carburetor etc. which are different between the two. Can we replace such parts one to one and get it converted?

- Has anyone got it done?

Thanks in advance for any useful input please.

Ray

 

  • Re: Convert 912A3 to 912S3

    by » 2 days ago


    Hi Ray,

    I own a Diamond DA20-A1.  It has a Rotax 912F3 engine.  Prior to my purchase, the previous owner upgraded from the 912A3 to the 912F3.  I'm not sure why Diamond was offering this upgrade path back then (The 912F3 and 912A3 both produce the same power level).  I think Rotax heavily revised some of the engine components (I believe the trigger coil design).

    The Super Dimona's were some of Diamonds first aircraft. 

    If you want to convert to the 912S versions, you will need to replace the entire engine.  You can't legally replace the internals to upgrade to the higher horsepower.  I think even if you could, price-wise it would probably just be cheaper to buy a new engine.

    The type certificate for the Super Dimona is available at this link:

    https://www.easa.europa.eu/sites/default/files/dfu/EASA-A-065-TCDS-h36-issue%2005.pdf

    In the type certificate for the HK36TC, it lists both the 912A3 and 912S3 engines, so there is an upgrade path to the newer engine.  For my aircraft you can get a field approval for the 912S3 upgrade.  Not sure what country you are in, but you could check with your local aviation authority about the upgrade.  There are probably some parts that you may need from Diamond (or Rotax) though: larger oil cooler, oil cooler bracket, new RPM gauge, possibly newer exhaust, possibly newer style airbox.

    For me, I have been looking into the 912iSC3 upgrade as the engine is "only" another $3-4k versus the 912S3.

    -John


  • Re: Convert 912A3 to 912S3

    by » Yesterday


    Hi All

    The difference is the certification.  The level to which the engine was originally produced with from Rotax.  A 912A3 is from the original JAR part 22 motorglider day VFR engine.  The 912F3 is made to comply to the FAR part 33 standards and has no restrictions for Day VFR, it can be used at night if the aircraft is correctly equipped electrically.  In this engine there are different fuel line components from Rotax and the configuration is noted in the build sheet from Rotax. 

    I don't know what is allowed under EASA  but for sure in the USA you cant change the original production certification standard by upgrades.  Even adding the TSO fuel system to the 912A3 will not make it a legal 912F3 engine as it was never produced with that approval.  The data on file from Rotax will always show only the approval at time of production. 

    I am sure that John is correct, you would have to replace the engine with one approved from time of production.

    Cheers


  • Re: Convert 912A3 to 912S3

    by » 17 hours ago


    Hi All,

    Thanks for your comprehensive responses. I understand now that there are two issues.

    1. Certification- Conversion from one to the other is not legally permitted. It would require a Supplemental Type certification from the engine manufacturer.

    2. Besides the certification issue, as John says, it won't make any economic sense too, since it involves many major parts. 

    Hence, conversion across the types is not possible. We need to maintain two different inventories for each type. 

    Thank you all once again,

    Ray

     


  • Re: Convert 912A3 to 912S3

    by » 14 hours ago


    Satyendra Prasad Ray wrote:

    Hi All,

    Thanks for your comprehensive responses. I understand now that there are two issues.

    1. Certification- Conversion from one to the other is not legally permitted. It would require a Supplemental Type certification from the engine manufacturer.

    2. Besides the certification issue, as John says, it won't make any economic sense too, since it involves many major parts. 

    Hence, conversion across the types is not possible. We need to maintain two different inventories for each type. 

    Thank you all once again,

    Ray

    Hi Ray,

    That is not correct.  The type certificate for your aircraft allows a Rotax 912S3 engine in addition to the 912A3.  You should be able to convert the aircraft to use the new engine 912S3.  As I mentioned, you may need to replace a few parts on your aircraft though.  Larger oil cooler, radiator, tachometer, etc.  Here is a link to the parts manual for your aircraft:

    http://support.diamond-air.at/fileadmin/uploads/files/after_sales_support/HK36_Series/Illustrated_Parts_Catalog/HK36T-IPC-r2-2013-12-10-complete.pdf

    I would suggest contacting Diamond aircraft.  They could tell you what parts would be needed.  For my aircraft, Diamond has a particular shop that they use to do the upgrade.  But, this can also be done with a field approval using your own maintenance shop.  it would be cheaper doing it yourself.

    I had thought you wanted to switch out parts such as pistons, etc on the old engine to make it have 100hp.  This is technically possible, but wouldn't be legal on a certified aircraft.  A lot of experimental operators do this.  There are a lot of after market companies selling these parts.  I would assume it could affect the longevity of the engine.  But again, in your case it is not legal.

    good luck.  -John


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