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Andrew Findley Takes 1st Place in EXP Sport AVC 2017 with SDS EFI

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rv6ejguy

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We're very proud of Andrew Findlay who took 1st place in the Experimental Sport Class in the Air Venture Cup Race last week in his twin turbo Lancair. Andrew is using our dual ECU 6F system for fuel and ignition control. He ran the plane at the Reno PRS in June also (middle photo).

findlay4.jpg findlay2.jpg findlay5.jpg

Andrew loves the individual cylinder trim function. He likes to even out the CHTs with it.

He's entered to run at Reno in September and I'll be there to assist him and some other SDS clients. We're hoping for good things in Sport Class but he has some tough competition there. Should be interesting.
 
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tspear

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Ross,

Very cool, and congrats to Andrew and your team. Can you ask Andrew why balance on CHT?
So far from what I have read and from the APS course, EGT is more predictable on air cooled engines due to less variance. Therefore balance on EGT is the preferred method.

Tim
 

rv6ejguy

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Ross,

Very cool, and congrats to Andrew and your team. Can you ask Andrew why balance on CHT?
So far from what I have read and from the APS course, EGT is more predictable on air cooled engines due to less variance. Therefore balance on EGT is the preferred method.

Tim
I just posted this on VAF a few minutes ago: As I was driving to work, I was thinking about this more. Andrew is a pretty smart guy. If we look at why we get different cylinders peaking at different times when we know we have near equal fuel flow, it's because the airflow to each port is not the same as I've discussed in previous threads. If we assume perfect baffling and cooling mass flow to each cylinder for discussion, perhaps Andrew's method makes more sense than what conventional EGT based trimming is doing for us. Assuming the prior statement, Andrew is tuning for equal heat/ HP in each jug which should equal smoother operation than the EGT method which equalizes AFRs but not power between cylinders, since internal airflow is not equal. Food for thought.
 

tspear

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I just posted this on VAF a few minutes ago: As I was driving to work, I was thinking about this more. Andrew is a pretty smart guy. If we look at why we get different cylinders peaking at different times when we know we have near equal fuel flow, it's because the airflow to each port is not the same as I've discussed in previous threads. If we assume perfect baffling and cooling mass flow to each cylinder for discussion, perhaps Andrew's method makes more sense than what conventional EGT based trimming is doing for us. Assuming the prior statement, Andrew is tuning for equal heat/ HP in each jug which should equal smoother operation than the EGT method which equalizes AFRs but not power between cylinders, since internal airflow is not equal. Food for thought.
I am by no means an expert on this stuff. So let's see how much I can screw up!

When you look at a lot of the old charts in APS and from Lycoming/CMI you see that CHT is closer then EGT in terms of the curve power matching power production under ideal conditions. (EGT gets kinda flat as you approach peak, but CHT mimics the power curve better). However, CHT is significantly more susceptible to cooling impacts, so this is the primary reason we use EGT.
Thinking about it more, I think Andrew is attempting to make peak power. He should be running slightly ROP and adjust the timing to get peak CHT per cylinder. Depending on internal airflow, this may not be the smoothest either or even the most balanced. To keep the engine from shaking apart, he would also need to be close to equal cooling.

To get a smooth as possible engine would go for identical fuel and air to each cylinder; and spend the effort on reducing the variances between the cylinders.

Now, how far off am I?

Tim
 

rv6ejguy

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I am by no means an expert on this stuff. So let's see how much I can screw up!

When you look at a lot of the old charts in APS and from Lycoming/CMI you see that CHT is closer then EGT in terms of the curve power matching power production under ideal conditions. (EGT gets kinda flat as you approach peak, but CHT mimics the power curve better). However, CHT is significantly more susceptible to cooling impacts, so this is the primary reason we use EGT.
Thinking about it more, I think Andrew is attempting to make peak power. He should be running slightly ROP and adjust the timing to get peak CHT per cylinder. Depending on internal airflow, this may not be the smoothest either or even the most balanced. To keep the engine from shaking apart, he would also need to be close to equal cooling.

To get a smooth as possible engine would go for identical fuel and air to each cylinder; and spend the effort on reducing the variances between the cylinders.

Now, how far off am I?

Tim
EGT is merely a way to judge AFR, stoich in this case. You don't really know what the AFR is on either side of peak EGT. Only a wideband can tell us that easily.

In the screenshot, Andrew is in LOP cruise, note the low FF, MAP and RPM. It's a different game racing where this engine will run up to 3200 rpm and 90 inches and we have ADI and spray bar water to keep it cool. It will also be running at best power AFRs.

Unfortunately getting equal airflow into the cylinders at all rpms and MAPs is immensely time consuming and expensive. I agree, that should be the ultimate goal though. In the real world you have to work with what you have. I disagree that equal AFRs can produce a smoother running engine when airflow is not equal in the first place. I believe we should trim for maximum smoothness rather than equal CHTs or having all EGTs peak at the same time. Max smoothness means that all cylinders are producing close to the same hp. Doesn't matter much whether one jug is at 16 AFR and another is a 16.5 really. Of course varying AFRs also varies flame speed and the point of PCP in the cylinders but by trimming for max smoothness we address all the variables.

APS can't vary the fuel trim across the board with conventional mechanical injection. I think this new EFI technology may force people to re-examine their beliefs and recommendations because control is so easily at your fingertips now- literally. As I said, food for thought.
 
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proppastie

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probably here somewhere else, but car's use oxy sensors, why not us?
 

rv6ejguy

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Swift fuels is already distributing UL94 in many areas in the US: https://swiftfuels.com/ul94-map/

Their higher octane UL102 is still undergoing FAA PAFI testing. I talked to one of the engineers at Swift and he thought it would be on the market in 3-4 years. This is the replacement for 100LL. The UL94 would work fine for the atmo engines most folks fly here on HBA.

GAMI is also testing their unleaded fuel but surprisingly, not under the PAFI initiative.

Shell made some noise a year ago but I haven't read anything lately about their UL fuels.

It's certainly coming here in North America but it's been a long wait. UL avgas has been available in several countries in Europe for over 15 years now.

We've had the closed loop technology in place on our automotive ECUs for 20 years now so it will be easy for us to add this to our aviation ECUs when UL fuels come into widespread use. We already have a rough schedule to release the initial control software for this late next year.

One challenge though on typical Lyconental engines is that many have poor cylinder to cylinder mixture distribution so a single O2 sensor will not do what it can on a properly designed modern auto engine. We may have to leave the trimming manual or develop proper intake manifold designs in conjunction with equal length exhaust systems to physically improve mixture distribution. In testing with flow matched heads and CFD developed intakes by Sky Dynamics, variations were cut down to around 3% which is acceptable. Another possibility is to look at EGT data to auto trim each cylinder.
 

rv6ejguy

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The race results were finally published today: http://www.airventurecuprace.com/racers/race-results/2017-race-results/

Notice Dave Anders who also flies with SDS was the fastest RV by over 20 mph beating a lot of Glass even.

Andrew is prepping his plane now for Reno, adding in the ADI and spray bar tanks and new forged pistons to handle the onslaught of 80+ inches of manifold pressure. He'll start to MAP the EFI to the upper power reaches in mid August.
 
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