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Torque values to attach blades to hub - MTO Sport (2010 model)

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  • Torque values to attach blades to hub - MTO Sport (2010 model)

    Since I was going to torque the blades to the hub right now this seems important. I might have an old Line Maintenance Manual and old Heavy Maintenance Manual.

    Line Maintenance Manual MMM-MT-B_14-11-19
    Heavy Maintenance Manual MMM-MT-E_16-06-13

    Both of these show on “ 01-12-00 Torque Values “ that an M8 bolt is to be torqued to 25Nm +/- 3Nm

    The latest 25 hour 100 hrs Protocol AG-F-PCA-MT-EN-V2 shows on Page 1 Rotor System to check torque the blade to hub bar bolts/nuts to 20Nm +/- 5Nm and points to the Job Card 62-11-00 4-3

    When I go to the Job Card 62-11-00 4-3 on both the Line and the Heavy Maintenance Manuals I find it shows in step 5 to torque those bolts to 15Nm.

    That’s 3 different torque values for the same bolt. So which is it?

  • #2
    Originally posted by Piot135pd View Post
    Since I was going to torque the blades to the hub right now this seems important. I might have an old Line Maintenance Manual and old Heavy Maintenance Manual.

    Line Maintenance Manual MMM-MT-B_14-11-19
    Heavy Maintenance Manual MMM-MT-E_16-06-13

    Both of these show on “ 01-12-00 Torque Values “ that an M8 bolt is to be torqued to 25Nm +/- 3Nm

    The latest 25 hour 100 hrs Protocol AG-F-PCA-MT-EN-V2 shows on Page 1 Rotor System to check torque the blade to hub bar bolts/nuts to 20Nm +/- 5Nm and points to the Job Card 62-11-00 4-3

    When I go to the Job Card 62-11-00 4-3 on both the Line and the Heavy Maintenance Manuals I find it shows in step 5 to torque those bolts to 15Nm.

    That’s 3 different torque values for the same bolt. So which is it?
    Check with Bob from AG - he will have your answers

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    • #3
      They're all gone for the weekend.

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      • #4
        I find this so interesting. You post a picture of a crash and there are 20,000 experts giving their expert opinion. I post a simple torque question on something that people do practically every week and none of the people who own MTOs and do this have an opinion. Very strange.

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        • #5
          My educated guess is 25 is the correct number. You're splitting hairs IMHO. I worry much more about my torque wrench's ACCURACY.

          I am familiar with the blueprints and build manuals of a few different aircraft. Typically, they post a torque chart in the beginning few pages of the manuals.


          Most of the people that fly don't come to this forum any more. There's a whole bunch of people flying gyros that NEVER visit this site so don't assume that every gyro owner visits this site regularly, if at all. Sad but true. I'm about done myself now that I have gathered some great info and advice over the years. You should develop a relationship with the AG dealer close to you. It is my impression that the most active AG dealers are further west than Maryland. There are countless charts on the web for aircraft bolt torque values. The proper torque of a given size bolt does not vary by manufacturer. It depends on the size and the grade of bolt. I can give you the engineering behind why we torque bolts to a specific value but you can look it up It's was fascinating to me when I looked it up 30 years ago.

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          • #6
            Thanks Tim. I would normally think the higher the better but was worried I might squish the blades somehow, they look so fragile.

            Anyway Chris Lord, who I think has to do with AutoGyro USA now, told me to use the one in the latest 100 Hour Inspection Checklist so I went with 20Nm (= 14.75 foot/pound). I guess that's a happy medium between 15Nm in the Job Cards and 25Nm in the Bolt Chart, and it turns out that 20 is what they recommend in the Inspection Checklist, so go figure. I also took into consideration the accuracy of the torque wrench so that also influenced me going to the middle of the range.

            So the blades were lined up with the string, all bolts torqued and have the crosscheck paint on them, now this afternoon when I get back home I'll lift the rotor system into the teeter tower and it should be done.

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            • #7
              Finally went for a flight this afternoon after completing the condition inspection. Smooth as silk all the way to 95 knots !!



              https://www.facebook.com/VacaMooAirp...1492055900111/



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