BK117

[Phoinix]

Hey FB!

Are these medical equipped, hoist? What BEM are we looking at? Thanks!

[Flying Bull]

Originally Posted by Phoinix

Hey FB!

Are these medical equipped, hoist? What BEM are we looking at? Thanks!

Nope - no medical equipment and no hoist - police role - wires for FLIR and WESCAM

[Phoinix]

Originally Posted by Flying Bull

Nope - no medical equipment and no hoist - police role - wires for FLIR and WESCAM

Right, thanks. Without the camera and flir; below 2000kg BEM?

[Flying Bull]

Originally Posted by Phoinix

Right, thanks. Without the camera and flir; bellow 2000kg BEM?

not quite...
TCAS, wires, long nose, sound proofing and some other added a little weight


BK C1 weight

[Phoinix]

Thanks for the help. Looking for a ballpark estimate.

[TwinHueyMan]

Reading through the B2 RFM, under limitations (sn 7253-sub or post SB 60-113 which I believe is the 125% gearbox) there is a note:

NOTE The engine is protected against over-TOT and over-torque by a STOP.

I can’t find any other reference to this, don’t believe it’s the collective pitch stop - does this imply that at TOT limits the engine will stop producing additional power (TOT limiting)? If so, does this mean in an OEI situation you can only expect TOT limits for power and nothing more should the situation be dire?

[wrench1]

Originally Posted by TwinHueyMan

Reading through the B2 RFM, under limitations (sn 7253-sub or post SB 60-113 which I believe is the 125% gearbox) there is a note:

NOTE The engine is protected against over-TOT and over-torque by a STOP.

I can’t find any other reference to this, don’t believe it’s the collective pitch stop - does this imply that at TOT limits the engine will stop producing additional power (TOT limiting)? If so, does this mean in an OEI situation you can only expect TOT limits for power and nothing more should the situation be dire?

The only engine limiting I recall was via the FCU topping stop. And yes, once that stop was contacted the rotor would droop as the engine(s) were "topped out" power wise. I believe the engine maintained the same the same speed/temp limits but the SB you mentioned allowed 125% max torque vs the previous 100% TQ.

[TwinHueyMan]

Originally Posted by wrench1

The only engine limiting I recall was via the FCU topping stop. And yes, once that stop was contacted the rotor would droop as the engine(s) were "topped out" power wise. I believe the engine maintained the same the same speed/temp limits but the SB you mentioned allowed 125% max torque vs the previous 100% TQ.

Interesting that it could limit the TOT with any reliability not being computer controlled… I also wonder what the actual TOT limit is at? Is it the 2.5sec OEI limit? The transient limit?

I wish it was more clearly articulated that if things go bad you more than likely will not have the 125% OEI torque available if you’re up at even a bit of altitude and that the engine will protect itself all the way to a smoking hole in the ground. Blackhawks have temp limiting (electronically controlled) and it’s warned all over the flight manual as well as clearly predicted with a torque available chart.

[wrench1]

Originally Posted by TwinHueyMan

Interesting that it could limit the TOT with any reliability not being computer controlled… I also wonder what the actual TOT limit is at? Is it the 2.5sec OEI limit? The transient limit?

The FCU topping stop limits fuel flow which in turn limits the TOT. So no TOT trigger. The stop setting also requires adjustment after certain maintenance tasks to ensure engine produces max design power. Below is a screenshot of the EASA TCDS which shows the TOT limits with the engine side remaining the same regardless of the SB 113 status.

[212man]

Originally Posted by wrench1

The FCU topping stop limits fuel flow which in turn limits the TOT. So no TOT trigger. The stop setting also requires adjustment after certain maintenance tasks to ensure engine produces max design power. Below is a screenshot of the EASA TCDS which shows the TOT limits with the engine side remaining the same regardless of the SB 113 status.

But I guess THM's comment:

NOTE The engine is protected against over-TOT and over-torque by a STOP

Was that it implies active TOT management, when in fact it is only Ng that is actively limited. I can recall doing topping checks in a 212 once, where I could not hit the Ng stop before reaching ITT limits. I stopped trying at 10,000 ft!

[wrench1]

Originally Posted by 212man

But I guess THM's comment: Was that it implies active TOT management, when in fact it is only Ng that is actively limited.

I think if that was the intent of the note, then it would also imply there was active engine TQ management outside of the transmission TQ limits considering the note states engine only protection.

I can recall doing topping checks in a 212 once, where I could not hit the Ng stop before reaching ITT limits. I stopped trying at 10,000 ft!

I always preferred performing the topping checks on the ground whenever possible, however, not all aircraft would permit that method. In flight topping could become interesting especially when at the moment you record the rotor RPM droop the engine not under test experiences a governor failure and everything gets a bit exciting.

[212man]

I always preferred performing the topping checks on the ground whenever possible, however, not all aircraft would permit that method. In flight topping could become interesting especially when at the moment you record the rotor RPM droop the engine not under test experiences a governor failure and everything gets a bit exciting.

Yes, the 212 had a part power stop (I think it was called) that allowed that, but I think it was for setting up and not for final verification.

There was an incident at Aberdeen Airport, but I can't find the report because the internet is saturated by more recent accidents of the 332/225 now. Engine replaced with bolts not tightened at the high speed shaft MGB connection (multiple shifts). During ground runs, the connection welded itself from overheating from friction, so was not evident. Commander elected to do the topping check in the visual circuit, with a 700 ft cloud base. Commander elected to manipulate the speed select levers while also the handling pilot. High speed shaft failed with the other engine at idle, on the downwind leg. Commander managed to get it onto a cross runway.

Sorry for thread drift.....

[TwinHueyMan]

Originally Posted by 212man

But I guess THM's comment:


Was that it implies active TOT management, when in fact it is only Ng that is actively limited. I can recall doing topping checks in a 212 once, where I could not hit the Ng stop before reaching ITT limits. I stopped trying at 10,000 ft!

It makes sense that NG is limited especially with the history of the PT discs on the LTS101… it just begs the question, what kind of TOT can you hope to get at XXX density altitude should it be a worst case scenerio OEI? Single engine performance in these older twins has always been “the first engine is the owners, the second engine is yours” but if the second engine won’t let you over temp it to get out of a bad situation then I believe the OEI performance charts (torque available charts?) should be much more robust in the RFM.

[wrench1]

Originally Posted by TwinHueyMan

It makes sense that NG is limited especially with the history of the PT discs on the LTS101….

A separate overspeed system was installed due to the disc failures. You’ll find a number of turbines with hydro-mechanical fuel control systems were designed to use a topping or trim procedure to adjust max engine power like the 101. Plus on this side of the spectrum, most models were transmission limited and you would smoke a transmission or twist a mast before your engine gave it up based on the components I've changed after a "dire" situation or two. But as I recall, most Sikorsky models were engine limited and would expense the engines to keep the blades turning which I always thought was a better priority in the big picture.

Originally Posted by 212man

Yes, the 212 had a part power stop (I think it was called) that allowed that, but I think it was for setting up and not for final verification.

Yes, part-power stop and one could sign off the check using that stop as the charts were calibrated for its use as it provided a more stabilized environment vs hanging at the outer limits of the power envelop. There was also a "slave" stop for the PT6s that allowed the check to be done on the ground, however, most used the built in part power stop in flight unless it was super cold outside.

[212man]

Originally Posted by wrench1

A separate overspeed system was installed due to the disc failures. You’ll find a number of turbines with hydro-mechanical fuel control systems were designed to use a topping or trim procedure to adjust max engine power like the 101. Plus on this side of the spectrum, most models were transmission limited and you would smoke a transmission or twist a mast before your engine gave it up based on the components I've changed after a "dire" situation or two. But as I recall, most Sikorsky models were engine limited and would expense the engines to keep the blades turning which I always thought was a better priority in the big picture.


Yes, part-power stop and one could sign off the check using that stop as the charts were calibrated for its use as it provided a more stabilized environment vs hanging at the outer limits of the power envelop. There was also a "slave" stop for the PT6s that allowed the check to be done on the ground, however, most used the built in part power stop in flight unless it was super cold outside.

Thanks - been over a quarter of a century!