Good info
Engine 5376 RPM! Hooche Moma! 201 mph at 8.9 gal/hr is not bad.
I guess a typical cruise mode will not be at full throttle:
prop 1800 rpm
eng 4608 rpm
eng 21.0 map
eng 8.2 FF
tas
190 mph
To put that into perspective a 160HP RV-7A at 75% cruises at
190 mph.
Fuel flow should be around 8.5 ga/hr at 2,400 rpm (ref. Lyc diagram IO-320 B,D part throttle fuel consumption). So the H6 is getting 0.30 gal/hr better fuel econ from my rough numbers @ 190 mph.
A Sam James cowl on the Lyc, would go faster (or burn less fuel) than Van's stock cowl. Assume max gain for SJ cowl on a Lyc RV-7A is 8 mph, in cruise say 4 mph. The Lyc with electronic ignition gets you 4% decrease in fuel flow, down to 8.1 gal/hr, plus a mph or two. The SJ cowl would be a notch up on speed (4 mph) and efficency, but with the stock numbers the H6 compares favorable with the 160 HP Lyc in cruise.
However interestingly enough at full RPM, 5376, even if you would not fly that way all the time the 201 mph at 8.9 gal/hr is like a 180 HP Lyc at 75% power at 9.2 gal/hr. Interesting. Again this is a stock Lyc and cowl. It appears the H6 is producing about what a 180HP Lyc is making and slightly better spacific consumption at full RPM. Again a EI would give the Lyc the same FF and the SJ cowl gets you a slight speed edge.
What does that mean? The new drive is doing good from these prelim numbers.
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It looks like the H6 is a true 180 HP engine (equivalent Lyc at the prop). It also looks like it is getting similar speed and fuel burn. In fact the burn to stock Lyc numbers from charts is slightly better. However with EI and SJ cowl the Lyc will have a slight advantage in both speed and econ.
Good for Eggenfellner. The big question is would one want to cruise at 5376 RPM. Also weight was not reported but suspect it is hefty affecting stall speed, takeoff/landing dist and climb rate.
I would like to know the empty weight of the H6 set-up on the RV-7 with the new prop and reduction.
Good info thanks George