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Bell 212 Best Rate Of Climb with FMS-29

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Bell 212 Best Rate Of Climb with FMS-29

Old 9th Apr 2019, 23:57
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Bell 212 Best Rate Of Climb with FMS-29

In the Bell 212 RFM it refers specifically to 58 Kts for Best Rate Of Climb (3-3-A) and the rate of climb performance charts all use 58 Kts as well. However, in FMS-29 "Increased Takeoff Horsepower" there is no direct reference to 58 Kts for Vy (VBroc) and the climb performance charts all use 55 Kts.

Any idea if Vy for FMS-29 is 58 Kts or 55 Kts? Any other thoughts on this?
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Old 10th Apr 2019, 09:12
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Use the Vy stated on the climb performance chart applicable to the operation.
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Old 11th Apr 2019, 10:47
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Not sure what FMS 39 is but sounds like it relates to the TB138/145 mods allowing higher T/O power. However, why would you expect Vy to change? Itís unrelated. Must admit my recollection is that Vy was 56 kts.
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Old 11th Apr 2019, 13:07
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55/56/59 Knots....just how accurate is the Airspeed Indicator anyway?

Gulli is right....if you are using a particular chart....use the Airspeed that is indicated on the applicable chart.

Reading the Supplement carefully should provide the information you need.

Memory tells me that if the FMS changes something in the FM.....it will be noted and that new data will supersede the FM original data.

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Old 11th Apr 2019, 17:30
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Keep in mind Vy varies with altitude. The RFM value is probably given for sea level and will increase ~1 knot per 1000’.

Disclaimer: I’m not familiar with the B212.
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Old 11th Apr 2019, 23:50
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From a Bell FMS....
.The information contained herein supplements the information of the basic Rotorcraft Flight Manual. For Limitations, Procedures, and Performance Data not contained in this supplement, consult the basic Rotorcraft Flight Manual and applicable Rotorcraft Flight Manual Supplements.
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Old 13th Apr 2019, 21:38
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Thanks, everyone. It is interesting. I assume that the "Increased Takeoff Horsepower" (FMS-29) mod must include some aerodynamic difference that changes Vy from 58 to 55. I think the tail rotor with the different yoke is part of this mod, but I'm not sure.

Also, is there somewhere that states that the speed used for the performance charts is, in fact, Vy or is that just common knowledge that I should just know?
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Old 13th Apr 2019, 21:46
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Was just told that the bigger tail rotor is not required for the Increased Takeoff Horsepower modification so that's not the answer either. Anyway, just being a bit pedantic but curious. :-)
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Old 14th Apr 2019, 20:12
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Me thinks 55 KCAS = 58 KIAS.
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Old 15th Apr 2019, 02:04
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As it was explained to me .”The numbers called for are for Standard ISA. and are IAS.
Of course as you go to ISA + you still use 58Kts IAS as TAS will be higher..at a higher density altitude.”
The guy was a Bell Pilot he made sense to me.
I could be wrong but he explained the chart was made to make it easy for the pilot in an emergency situation.

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