How to read this?

[Atomic_Sheep]

Hi,

Trying to understand this graph. WOT I'm guessing means wide open throttle? At least according to google, that's what it means. Which basically means that the only way that you can have different consumption at different RPMs would be at different altitudes? But in the caption of the graph, it's also stated that the graph was taken at a constant pressure. So now I'm confused. If it's taken at the same pressure, that likely means the graph was derived on a ground test which begs the question, how can you have WOT and have a range of RPMs other than max?

Ansaugdruck translated into suction. The engine is electronic injected.

[Heston]

. how can you have WOT and have a range of RPMs other than max?


By having a different load on the engine? Different propellor or the same propellor at different airspeed, or a variable pitch propellor.

[BackPacker]

Agree. I think this is a manufacturers graph that's used as input for the airframe manufacturer to eventually come up with the speed/power/map/rpm/fuel consumption figures that go in to the POH. A graph like this would be virtually useless for the pilot.

The other thing to note is that the "ECO" lines are most likely "leaned for best economy" while the "Power" lines are most likely "leaned for best power".

What engine is this by the way? It's not your typical Lycosaurus, which has a maximum RPM in the 2700 range. Must be something geared. Rotax 912Si or 912ULSi?

[PDR1]

It looks to me like a graph of fuel consumption against RPM for a range of throttle settings (identiofied by manifold pressure). So each line is the essentially variation in fuel consumption you'd get if you left the throttle alone and played with the propellor lever for that throttle setting.

PDR

[mikehallam]

I concur PDR,

Suction is at manifold gauge showing increasing throttle opening till at 950 mbar and above it's Full throttle (WOT is a well known short-hand for that).

I couldn't see what the power actually was, but converting from 0.45 lb fuel per h.p. gives approx 97.6 h.p.
Could be the new bigger Rotax, except it's unlike their usual graphs (for the 912 series).
One of the flat four Belgian motors ('D' or ....?)

mike hallam

[scifi]

Looks like the results of putting the engine on a variable Brake in the lab, and plotting fuel flow against manifold vacuum, to simulate various throttle settings or altitude changes.
.