Very cool....but how much beer was Dave hauling?
Apples to apples, add a week's worth of clothes, camping gear, and my big butt too.
All kidding aside, that's not a crazy guess. At very small fuel flows the EFI can produce great cylinder balance with the new on-the-fly trim, and with dual EI's to fire it, get very lean. An optimized constant flow (small restrictors, and tuned for the specific conditions) could probably get close, but certainly would not be as easy to tune.
Remember this?
Returning to Fig.2, that is 35X higher than the mechanical system's pressure at a 6 GPH economy cruise flow. At idle the difference is even greater. The injector open time can be tailored for a small flow quantity, but the pressurized spray remains consistent and well atomized. You can expect the EFi system to be smoother at idle and partial power.
And this?
That's a 540 with a Bendix RSA-10 and Slicks (in beige) and dual EI and EFI (in blue). On the dyno, the EI/EFI combination would pull much leaner without significant torque loss. Here, the difference was 1.5 GPH saved with minimal loss of power. BSFC went from .525 to .483. That's an EI/EFI win, and precisely the sort of thing Dave is now demonstrating live with his RV-4.
It's from Kitplanes. At the time I was handed a lot of grief because the peak HP numbers were not what EFii fans wanted to see. The knowledgeable guy who did not find fault was Ross.
Folks, this is what EI/EFI does really well.
Certainly very impressive RV4 . Slightly off topic, which Wheel Pants are you running? Sam James or Vans?
Thanks
Tim
Dave Anders was mightily impressed by your GAMI spreads and especially CHT spreads. Your data made him run some more tests and I think he intends to tweak cooling a bit more to try to get where you are.
From Dave today:
"I use Klaus Savier wheel pants from Lightspeed Engineering . I think they are a bit better than Vans?. They?re smaller and lighter. I also run Lamb tires. I have landed on grass strips with them but they?re small and probably harder on your landing gear with rough rwys. I use less ground clearance so less exposed tire as compared to Vans? recommendation and I prefer asphalt rwys."
Ross, can the EFI use an external electronic ignition tach source rather than its own pickup for rpm info?
We've had some interest in developing EFI for the M14P radial. Hopefully start on that project in Sept. when all of our Lycoming 6 cylinder developments are done.
Yes, in fact Dave here is running his SDS ECU off the Lightspeed tach signal. The Lightspeed II does not output a compatible tach signal but the III does.
For the EM-5 ECU, we can work with any voltage between 5 and 200 volts, 2 pulses per crank rev for fours and 3 per crank rev on sixes, having something close to a square wave.
We've had some interest in developing EFI for the M14P radial. Hopefully start on that project in Sept. when all of our Lycoming 6 cylinder developments are done.
This should make mixture control completely automatic as Dave said from SL to very high altitudes.
Now we're talkin'! I do assume you mean "mixture stable", i.e. the ability to set a particular A/F ratio, and it stays there regardless of altitude change. Best power (ROP) or best economy (LOP) is still going to require pilot selection.
12.2 to 12.4 in 8500 feet is pretty darn good. The 12.2 to 13.0 shift in 15,800 very roughly compares to some data I got with an AFP FM200 last year, a shift of approximately 12.5 to 10.0 in 13,000 feet of altitude change, at WOT and mixture knob full rich.
Note the experimental system going leaner with altitude gain, rather than richer. I doubt it made any difference in Dave's CHT because power was also dropping off with altitude.
The EI I have from Robert Paisley is limited to 30 degrees advance.
Is that so with what is being discussed here?
Also, how is reliable A/F ratio indication being maintained. I had trouble with it burning 100LL.
The pilot must still make the change mixture for LOP but even that is being simplified in V29 with the flip of the advance switch which can also lean the mixture a pre-set, programmable percentage.
Many of our customers who usually fly in fairly narrow altitude/ power setting spreads have noted that they usually lean close to the same knob percentage each time. Now you'll have the option of throwing the switch and timing advance/ leaning to LOP will happen simultaneously.
The over leaning response with altitude increase is due to reduced exhaust back pressure making the engine effectively pump more air. This turns out to be pretty significant at high altitudes.
This is what I was hoping for all along!
Dave has been trying to sort out an intermittent fault which appears to be related to a TPS issue. He's now using the EM-5 PC data logging option to look at what's happening during the flight. This option allows the user to look at, store and print ECU data to aid tuning and diagnostics.
<snip>
The data logging feature often allows us to quickly solve customer tuning or running issues. The files are small and can be emailed to us for playback.
Oh I had to look it up - it's YOUR data logger, excellent!!
Having an interface box makes that super easy - not another development project for a data logger.
He's running a 65mm throttle body and new pressure recovery ram intake design which is netting 1.5 inches more MAP than ambient and .6 better than his best previous design.
We're now working on a solution to fix rising EGTs at very low MAP when the throttle is pulled back at mid rpms. This may be due to the LS ignition advancing a lot but we're investigating other possibilities with fuel mapping too.
Advance should lower EGT's, should it not?
Perhaps the effect of the prop driving the crank? Back in the day I had to jet a blue head Rotax a bit on the rich side to keep the EGT's from spiking past limits on downlines.
https://youtu.be/h8cWKi4Ir6E
Ross,
Are y'all selling that injector adapter separately, to us DIY'rs? Couldn't find them on your web site, last time I looked. They should fit a 320 without issue, right?
Charlie
It appears Dave has directed his oil cooler air downward, but it seems to dump behind his exit fence, is that correct? Or is there something we don't see?
Ross, thanks for that top picture. That answers my a nagging question on how to direct airflow into the cylinders. I have been stalled on that area between the cylinders.
Another question. It appears Dave has directed his oil cooler air downward, but it seems to dump behind his exit fence, is that correct? Or is there something we don't see?
The March 2017 issue of Kitplanes features an outstanding article by Dave Andrers, "Putting the Experiment in Experimental".
A portion of the article is dedicated to his use of the SDS EFI and Light Speed Plasma EI on his RV-4. Articles like this help me better understand the advantages of these more sophisticated systems and how they improve performance and economy.
It would be interesting to hear more about his electrical system. I don't see an alternator in any of the photographs. Maybe there's one on the back of the engine accessory case.
Back to spectating and learning.
In the meantime, he sent some more photos of his cowling ducting arrangement. His usual, very nice work: