Paul K
Well Known Member
I noticed a really high fuel flow rate during a takeoff yesterday, it lasted for about a minute and then went back to normal. Some background:
RV7a
IO360
Cold air induction
WW RV200 prop
Red cube transducer
WOT
Full Mixture
Prop all the way in, 2650 rpm
Air temp 35f
Winds calm
Full tanks, 100LL
With passenger
GRT Horizon and EIS but didn't have the record function running.
These conditions usually show a max fuel flow rate of about 17gph. For this launch, the GRT warning went off and I saw 27gph! As soon as we were at pattern altitude and on downwind, I retarded the throttle, prop, and mixture and all went normal. Boost pump on/off, no difference. Obviously thinking leak downstream of the transducer, I landed and checked everything. No fuel anyplace and nothing out of order! Wires good, plumbing good, everything!
So, I climbed back in, sans passenger, and took it around the pattern a few times including a couple touch-N-go's. Everything normal!
After thinking about it, I continued to test it in the air (after landing again and looking for anything our of place) doing about everything I could think of, pump on, pump off, full lean, full mixture, dial prop in, dial prop out, WOT, or not, pulled several 3G turns, steep climbs as if taking off, and every combination of everything I could think of, and couldn't get it to happen again.
The question is, what caused the very high flow indications and is this a messenger that something is failing?
RV7a
IO360
Cold air induction
WW RV200 prop
Red cube transducer
WOT
Full Mixture
Prop all the way in, 2650 rpm
Air temp 35f
Winds calm
Full tanks, 100LL
With passenger
GRT Horizon and EIS but didn't have the record function running.
These conditions usually show a max fuel flow rate of about 17gph. For this launch, the GRT warning went off and I saw 27gph! As soon as we were at pattern altitude and on downwind, I retarded the throttle, prop, and mixture and all went normal. Boost pump on/off, no difference. Obviously thinking leak downstream of the transducer, I landed and checked everything. No fuel anyplace and nothing out of order! Wires good, plumbing good, everything!
So, I climbed back in, sans passenger, and took it around the pattern a few times including a couple touch-N-go's. Everything normal!
After thinking about it, I continued to test it in the air (after landing again and looking for anything our of place) doing about everything I could think of, pump on, pump off, full lean, full mixture, dial prop in, dial prop out, WOT, or not, pulled several 3G turns, steep climbs as if taking off, and every combination of everything I could think of, and couldn't get it to happen again.
The question is, what caused the very high flow indications and is this a messenger that something is failing?