R44 aircon - affect on fuel consumption?

[Dantruck]

Anyone got real figures on the affect the factory-installed, standard Robinson air-conditioning system has on fuel consumption, please? The craft in question is a new R44 Raven II.

Ideally, I could use numbers for both the 'intermediate' and 'high' settings; not estimates please, but numbers you've actually measured.

It would be...er!...cool if you do.

Cheers
Dan

PS: Yes, I have trawled with the search function, but come up with nowt

[What Limits]

Don't really know and don't really care but I used it today and reminded myself that it is awesome!

[darrenphughes]

Don't use it, fly a little higher with the vents open and you don't have to worry about the extra consumption!!

Probably doesn't answer your question though!!

[Stan Switek]

I completed the RH Factory Course recently. The only mention of the AC was that it automatically shuts off in the event you pull near max MP. There is no fuel consumption table in the R-44 POH. Frank wanted it that way.

[HFT]

Just completed 3000 mile trip in company with a/c version R44II and my machine hasn't air, no noticeable difference in fuel consumption. In fact the a/c equipped was 3-5 knts faster for same indicated manifold pressure and similar weight. Raven I with us pulled 1-2 more map and had one extra pax used 6-7 lts extra for each leg but kept up with us RII's no problem.

[Runway101]

Doesn't the POH mention the air condition consumes 3hp (or was it 1hp) extra? Don't have the POH handy I am in China right now...

[northpoint]

R44 Aircon

An engineer told me it adds 0.1 litre per minute to fuel consumption. Normal fuel consumption is 1.0 litre per minute at max continuous manifold pressure.

[Bravo73]

So, in effect, it adds 10% to your fuel bill? In the current climate (no pun intended!), that seems like quite a lot.

[Overdrive]

10% extra fuel consumption is actually a good approximation for almost any kind of fairly modern vehicle with a relatively strong air con. system.

[Dantruck]

Gracias northpoint and others.

Someone else profered the +10% theory to me, also. That figure seems to be the perceived wisdom, at least for now.

I will attempt to report back when I've completed a like-for-like series of flights...Spanish Air Traffic permitting........(don't get me started)

Dan

[topendtorque]

surely it would have to be a direct ratio of the power required for each function. I.E. if the compressor is dragging 3hp, which for modern equipment is a fair bit, but just suppose it is that at lower level on a hot day and you were using max continuous of 220hp say. that would give you less than 1/60 of the normal consumption???

would one need to switch the aircon off at higher cooler temps? surely there is a little thermostat gadget that would only demand the power required to cool the difference between that selected and OAT.

[Runway101]

Originally Posted by topendtorque

surely there is a little thermostat gadget that would only demand the power required to cool the difference between that selected and OAT.

I am not sure that this is the way the R44 air con is designed. There is only one switch: off, low and high. It doesn't have a device where you could select an air temperature of 22C for instance.