Fuel consumption rate.
 

Hello folks.
I am looking at helicopters and powerplants, and they have data.
I am however curious with fuel consumption.

1. How do we know if a fuel consumption rate is high, low or good, not-so-good, and so on?
2. Is it even significantly important?
3. What powerplant has the best fuel consumption rate?

Those questions are hard to answer.
1. Good fuel consumption based on what? Engine power? Helicopter weight? Speed? Range?
For example, AW101 burns ~3.5 l/km. AS 350 burns ~1 l/km. But 101 carries a hell of a lot more payload.
2. see above.
3. IDK and can't be bothered to google it, so I'll go with one that is shut down.

Litres per kilometre ? Not kilograms per minute?

A 200l drum can run a B206 for 2.5 hrs with a bit left over.

Cant be doing much work with the 206 then !

load-lifting (short lifts) the 206 burns half a barrel an hour (102lts). so that equated to 2 hrs of hard work with nothing left over.

It was on powerline inspections, bopping along at 20-30kt at powerline level. Mostly the 2.5 hr limit was my bladder.

The smallest powerplant working the hardest.
Arrius at 100% ~500Hp
Arriel at 50% ~500hp
in that case would guess Arrius use less fuel

1. For an engines efficiency, look no further that its specific fuel consumption (SFC) and use the lb/(shp-h) as a comparison from one engine to another.
2. In principle, a reduction in SFC, means more range or better payload and of course reduced operating costs.
3. As for the most efficient engine type. It is going to be a recent design, incorporating the very latest technologies. Something like the GE38 on the 53K is around 0.4 lb/(shp⋅h), but I would hazard a guess that the GE T901 is even better and likely in the region of 0.3? lb/(shp⋅h).

Nick Lappos told me once in order to extend endurance time in a multiengine helicopter, fly at max endurance speed and bring one engine back to idle and watch your fuel flow decrease. So we tried it briefly and there was a discernible reduction in the total fuel flow. Pertinent here ? No idea, thought it was an interesting experiment from a long while back.

A turbine engine at idle is using quite a lot of fuel to self sustain yet provides no useful power. A better option is to shut one engine down completely.

Thank you for taking out to respond to this thread.

Looks like these days even aircraft powerplants are going hybrid too.
Fuel consumption is really like an outdated term.

R44 (Lycoming I0-540) burns 15 USG/hr of AvGas. R66 (RR300) burns 23 USG/hr of JetA.