rv6ejguy
Well-Known Member
As we've seen from comparisons, the EFI is not a lot better than a well sorted mechanical FI at "normal" cruise power settings. More of the gains come from advancing ignition timing to the proper figure when LOP.
Forget the airframe as that doesn't enter into BSFC numbers. While I'm not at liberty to release all the details about Dave's engine and some of the dyno testing it's undergone at this time, feel free to work out the approx power and BSFC yourself from the MAP and rpm shown in the screenshot vs. the fuel flow. AFR was 16.7 in this screenshot. It's presently a 10 to 1 engine with ported heads and revised cam timing. This is not even optimized. An AFR of 17.5 to 18 would give slightly better BSFC figures.
A new engine is in the works, upping the CR a couple more points again.
The big issue with TE and the Wankel is the high surface to volume ratio and high heat losses.
Make sure any flight testing comparing piston and Wankels are both using optimized leaning techniques and optimized fuel and spark control, otherwise the results aren't very meaningful.
I've never seen or read anything reputable from car, airplane or dyno testing that Wankels are anywhere close to modern SI piston engines in BSFC under similar running conditions. The RX8 was abysmal in the real world as were all the previous iterations. (I know, I've owned a couple of them) If you have some data you'd like to share, please do. I'd be very interested.
For military use, certainly heavy fuels makes tremendous sense no matter which engine design is being used.
Forget the airframe as that doesn't enter into BSFC numbers. While I'm not at liberty to release all the details about Dave's engine and some of the dyno testing it's undergone at this time, feel free to work out the approx power and BSFC yourself from the MAP and rpm shown in the screenshot vs. the fuel flow. AFR was 16.7 in this screenshot. It's presently a 10 to 1 engine with ported heads and revised cam timing. This is not even optimized. An AFR of 17.5 to 18 would give slightly better BSFC figures.
A new engine is in the works, upping the CR a couple more points again.
The big issue with TE and the Wankel is the high surface to volume ratio and high heat losses.
Make sure any flight testing comparing piston and Wankels are both using optimized leaning techniques and optimized fuel and spark control, otherwise the results aren't very meaningful.
I've never seen or read anything reputable from car, airplane or dyno testing that Wankels are anywhere close to modern SI piston engines in BSFC under similar running conditions. The RX8 was abysmal in the real world as were all the previous iterations. (I know, I've owned a couple of them) If you have some data you'd like to share, please do. I'd be very interested.
For military use, certainly heavy fuels makes tremendous sense no matter which engine design is being used.
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