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Dave Anders Flying SDS EFI

Test Data on Head Mount vs. Tube Mount Injectors

Dave finally had some decent weather:

"I was able to test today to compare the 60 lb injectors on the induction tubes verses the 46 lb injectors on the heads.

OAT varied today from 59 degrees F @ 600? decreasing to 17 degrees @ 17500? Palt. Tests with the 60 lb injectors were done with OATs from 97 at 600' to 23 at 17500?.
Time to climb from 600' to 17500? Palt 10 minutes 28 secs @110-120 mph IAS, full fuel and with everything in the plane that is always there included the O2 system. So the climb is about the same.

It generally seems the max mpg and max speed is about the same, maybe slightly less on the mpg. I don?t know why that would be perhaps the difference in the injector spray pattern.

Injector temps in degrees F: OATs on the days tested were different as indicated below.
4000' OAT 52 59
#1 63 #2 71
#3 67 #4 84
It appears the injectors operate at around 11-25 degrees above ambient. During the test today, the #1 & #3 continued cooling during the climb to 17500? until #3 indicated 38 degrees F and #1 wouldn?t register a temp (below 32) at an OAT of 17 degrees at 17500?. It still demonstrated 11 degrees above ambient in those conditions. It may be that the injector temp is actually lower than the recorded temps due to the cold fuel flowing through the injector.

The gain above ambient with the tube mounted 60 lb injectors was about 160 degrees so it left little room for the 284 degree F max injector temp. However, with OATs during the 60 lb injector tests being 90 -100 F the maximum temp I observed was 274 F under the most adverse conditions with the injectors in my original location.
I will get comparable temps when the OAT comes up in the summer and the heat rise after shut down.

Vmax:
injectors
17500? Palt 60 lb 16.4? MAP, 12.4 AFR, 2820 RPM, OAT 23 F, AFR 12.4 232 MPH TAS
46 lb 16.3? MAP, 12.8 AFR, 2820 RPM, OAT 17 F, AFR 12.8 231 MPH TAS
6900? Palt 46 lb 24.6? MAP 12.8 AFR, 2800 RPM, OAT 55 F, AFR 12.6 241 MPH TAS
5500? Palt 60 lb 26.0? MAP 12.4 AFR, 2800 RPM, OAT ? , AFR 12.4 243 MPH TAS
1500? Palt 46 lb 30.1? MAP 12.6 AFR, 2820 RPM, OAT 60 F, AFR 11.0 243.5 MPH TAS

EGTs & CHTs:
Injectors 60 lb 46 lb 46 lb
Cruise: EGT CHT EGT CHT Vmax EGT CHT
1. 1292 296 1166 296 1241 287
2. 1304 295 1173 291 1337 291
3. 1273 277 1160 282 1302 292
4. 1253 295 1158 307 1299 300
spread 51 19 15 25 96 13

I may have had #1 cylinder trimmed a little rich Vmax test because I believe that cylinder CHT should have been hotter than #2.

It appears the cylinder trim is more variable with the 46 lb head mounted injectors requiring different percentages of trim for each cylinder at different power setting and is perhaps more sensitive.
I intend to get better numbers and check it again before reporting.

It runs smooth at 17500' all the way to 19.7 AFR and down to 3.6 gph if the cylinders are trimmed.

For the ease in installation in the heads verses the induction tubes, the performance difference, if any, is not worth the effort."
 
Dave made it to Mojave for the fly-in Saturday and met up with Bill Beaton and Ralph Inkster.

On the way home, he posted these numbers-"...good economy with with reasonable speed, running only 20.2? MAP, 2220 RPM, FF 6.0 GPH, 33 MPG, 190 MPH TAS with a 17 mph XW, at 37% power, and at 17.0 AFR. This is just our normal low power cruise.
We were 4.2 gal into the flight at that time and still had a range of 911 miles with remaining 27.8 gals. We get about 2% more per 1000? increase so it kind of indicates what it does at altitude."
 
Altitude??

Dave likes to fly high... Like flight level high.

I spoke to Dave and Bill at length yesterday and got the distinct impression that they are very happy with their SDS systems. Dave reports that the difference in injector temperature on his setup between the tube mount and head mount is significantly better with the head mounts. With the head mount he's seeing something like 10 degrees above ambient air, while the tube mounts were much closer to the limits of the injectors. Daves were mounted on the inside of the tubes however, but the takeaway for me is that I'm a lot more relaxed about my head mount injectors and will simplify my originally planned plumbing scheme. Nothing but good news from both Dave and Bill.
 
Yeah, that's what I figured. Not arguing about the great numbers, but it's worth pointing out that not many of us mere mortals will see anything like that without canulas stuck up our noses. I start getting woozy when I climb above the crop duster levels. :)
 
Yeah, that's what I figured. Not arguing about the great numbers, but it's worth pointing out that not many of us mere mortals will see anything like that without canulas stuck up our noses. I start getting woozy when I climb above the crop duster levels. :)

Ahhhh...it says 20.2" MAP, ballpark 10K if not throttled, lower if throttled.
 
Yeah, that's what I figured. Not arguing about the great numbers, but it's worth pointing out that not many of us mere mortals will see anything like that without canulas stuck up our noses. I start getting woozy when I climb above the crop duster levels. :)

While Dave often flies extremely high, I'm guessing the trip back home yesterday was much lower than normal, so his numbers are representative for the rest of us.

Interesting point that Dave made to me yesterday was with the barometric compensation built into the EM-5, Dave can climb from sea level to 18k and the AFR stays rock solid without having to touch anything. Truly hands free mixture control now.

Also interesting is the extreme contrast between Dave's search for maximum efficiency and Bill Beaton's search for Reno race winning engine output- yet both find it in the SDS EM-5 system. These guys pretty much bookend the performance spectrum for the rest of us, so if they're happy, then there is a very good chance the rest of us will be too.
 
Mohave award Best Design

Very nice meeting Michael & Dave at Mohave. It's good to put faces to the posters on VAF.
Bill Beaton & I felt it deserving to put forth Ross & Barry of Racetech up for recognition in front of the Mohave judges. Our presentation highlited the many customer generated features added to their SDS EM-5 & CPi systems in the last 2 years. We also wanted to mention the many years SDS has been changing the nature of homebuilt aircraft engine management.
Happy to say we are bringing back an impressive Mohave Best Design trophy for Racetech's wall. Congrats Ross & Barry!
You might have to wait a few days to get the trophy, Ross, as the RV8 & Bill's Rocket refused to turn north, they diverted us to Phoenix instead. What plane or pilot in their right mind wants to fly back to Calgary's spring weather...
 
You're talking about hot start? Fuel is not boiled off as in mechanical fuel injection systems. The fuel going to the electronic injectors is maintained at what ever the pressure regulator is set at, be it 35, 40 or higher psi. Fuel in the lines leading to each electronic injector will not form vapor bubbles because it is under pressure.
 
Ralph gave me a call this afternoon saying that the judges at Mojave awarded us the Best Design trophy. I'd really like to thank Bill Beaton for coming up with the idea to do the presentation in Mojave and to him and Ralph Inkster to actually fly down and give it.

I'd also like to thank our many customers who've contributed great ideas on new features they'd like to see and given us feedback on how to improve the products and documentation- especially Dave Anders, Michael Robinson, Rusty Crawford, Caleb Lesher and Gaylon Koenning. All great folks to work with.

We've got some other new projects in the pipeline for release in mid 2017 and early 2018, just starting the R&D on those now as time permits.

I'd finally like to thank my friend and 23 year business partner, Barry Wilks, who's the real brains behind the electronics and software. One of the smartest guys I've ever met.

Anyway, this award means a lot to both of us and validates our hard work over the years. We look forward to bringing even better and more capable stuff to the market in the future.
 
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You're talking about hot start? Fuel is not boiled off as in mechanical fuel injection systems. The fuel going to the electronic injectors is maintained at what ever the pressure regulator is set at, be it 35, 40 or higher psi. Fuel in the lines leading to each electronic injector will not form vapor bubbles because it is under pressure.

I was actually thinking about the max allowable injector temperature. I would assume that without airflow, the injectors would heat up to the same temperature as the CHT.

Paige
 
Thermocouples on the injector housing showed a max temp of 174F after 10 minutes with the heads at about 280F on shutdown so the injectors don't get anywhere near as hot as the heads.

Remember that the CHT is measured deep in the head near the chamber floor and the injectors are screwed into the intake port which can be 200F cooler than the core of the head when running due to airflow and fuel vaporization.

Second, the material of the threaded portion purposely has poor heat conduction properties. The injector does not touch the metal parts of the adapter as it's located with O-rings and the injector we use has a stainless steel body which also has poor heat conduction.

As the heat flow travels from the core to the fins and other cooler parts, the core temperature starts dropping rapidly.

While others have a "feeling" that you might have hot start issues, the instrumentation shows the injector to be cooler under all conditions than those mounted under the heads near the exhaust stacks plus actual hot weather testing shows no hot start issues with the injectors mounted in either location.

Remember that EFI is totally different than Bendix type mechanical FI since EFI runs the FP at around 40 psi while Bendix FI has only a few psi at idle. The high FP with EFI means the fuel boils at a much higher temperature than on Bendix type systems as soon as the engine starts to crank.

In flight, where the engine spends more time and is a more important regime, injectors temps are 150-200F cooler with the top mount injectors compared to induction tube mounting as they're bathed in ambient air rather than air passing through the head finning and adjacent to the 1200F+ exhaust stacks.
 
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Sorry, we don't. Have to reserve production for our complete kits. We do sell the weld in ones separately.

Hi Ross,

Was the answer to the second component of the question an affirm?

i.e they should fit a 320 without issue?
 
Ross,

Any updates to share? Any chance you could give some info on how Dave has his electrical system set up?

What alternator? Where? One or 2 batteries?
 
Dave is coming along with his top injector installation and hopes to be testing next week.

daveinj1_zpsgihzvwlu.jpg


Uber clean job installing the wiring and hard lines.

Dave did have to cut some small reliefs into the heads to clear the bosses on his engine BTW.

This photo shows the Alt on the accessory case. No belt drive alternator detected. This option appeals to me for my consideration of the SDS system in that it removes the supposed vulnerability of the alternator belt from taking out the crank sensors.

Any downside to a system like this?
 
This photo shows the Alt on the accessory case. No belt drive alternator detected. This option appeals to me for my consideration of the SDS system in that it removes the supposed vulnerability of the alternator belt from taking out the crank sensors.

Any downside to a system like this?

Assuming you're using a vacuum pump pad-driven alternator: Since that splined shaft only rotates at 1.3x crankshaft RPM, you'll get very little output at idle/low RPM (belt-driven alternators typically run >3x crank RPM).

Heinrich
 
...This option appeals to me for my consideration of the SDS system in that it removes the supposed vulnerability of the alternator belt from taking out the crank sensors...

There may be some good reasons to move the alternator off the nose of the engine, but hall sensor vulnerability is pretty low on the list. The SDS mount itself is strong enough to hook a chain to and lift the engine. The wires are really the only weak part and they can easily be armored enough to withstand a shotgun blast if that's what you require.
 
This photo shows the Alt on the accessory case. No belt drive alternator detected. This option appeals to me for my consideration of the SDS system in that it removes the supposed vulnerability of the alternator belt from taking out the crank sensors.

Any downside to a system like this?

You need roughly 8-9 amps at idle to feed the EFI hardware plus whatever other loads you have. If you can do that with a a couple pad mounted alternators, it's viable.

Have not heard too much from Dave lately. He flying and doing some new mods for the Air Venture race I believe.
 
Mechanical pump use?

You need roughly 8-9 amps at idle to feed the EFI hardware plus whatever other loads you have. If you can do that with a a couple pad mounted alternators, it's viable.

Have not heard too much from Dave lately. He flying and doing some new mods for the Air Venture race I believe.

Ross: Is this still the load if a mechanical pump is used?

Thanks!
Mark
 
Mark,

Are you asking about a stock engine driven pump? I don't know of any that will approach the 40+ PSI needed for automotive style injectors.

Ross,

Are you saying your system will work with the ~25 PSI from a Lycoming style engine mounted pump?
 
Mark,

Are you asking about a stock engine driven pump? I don't know of any that will approach the 40+ PSI needed for automotive style injectors.

Ross,

Are you saying your system will work with the ~25 PSI from a Lycoming style engine mounted pump?

People are flying with modified aircraft mechanical pumps using our EFI. Fuel pressure needs to be in the 40 psi range.

We'll be offering a smaller electric pump in late July for sub 150hp engines. This reduces pump current draw from around 4.5 amps (normal medium pump) to 3 amps. Mainly offered for Rotax 912 and Jabiru engines which have wimpy charging systems.

We also offer a larger pump for engines over 350hp which draws around 5.5 amps at 40 psi.
 
Well, now I'm in Sgt. Shultz mode...

Can you share details on the mod to the Lyc style pump? Just increased return spring pressure? Which spring is used? Enough hours to tell whether there'll be problems with extra wear on the actuating cam & pump arm?

The automotive injection pump is the highest consumer of electrons, *and* drives the need for a mechanical bypass regulator, so if there's a way to do a diaphragm style pump driven by the engine, that simplifies both plumbing and electrical needs.

Charlie
 
Well, now I'm in Sgt. Shultz mode...

Can you share details on the mod to the Lyc style pump? Just increased return spring pressure? Which spring is used? Enough hours to tell whether there'll be problems with extra wear on the actuating cam & pump arm?

The automotive injection pump is the highest consumer of electrons, *and* drives the need for a mechanical bypass regulator, so if there's a way to do a diaphragm style pump driven by the engine, that simplifies both plumbing and electrical needs.

Charlie

I'm not sure of the mods done to the pumps, resultant life reduction etc. One is a Sport Class Continental which is a different design than the standard finger drive Lyc pump. I believe the Lyc users have fitted the Lear type rotary pumps.

Plumbing is not really simplified with the mech pump and you still need the bypass regulator to maintain proper differential over MAP for precise metering since pump output exceeds engine usage.

The twin electric pumps have proven to be 100% reliable to date if mounted and filtered as we recommend. The current draw is only a concern if you lose the alternator. We recommend either twin alternators (small vacuum pad one is fine for backup) and/or a backup battery with our EFI systems.
 
Ross,

Do you have a preference for 2 alt and 1 battery or 1 alt and 2 batteries?

I can see that Dave has at least 1 alt mounted on his accessory case but there may be a second one back there I can't see I these pics.

Any idea how his electrical architecture is set up?

Is it 1 alt 2 batteries?

Thanks
 
I'm not sure what Dave is using for electrical backup but he has a mechanical fuel backup to make enough engine power to get the aircraft to a runway if the EFI was to fail. His LS EIs would only draw 2-3 amps at cruise rpm.
 
That's a really cool feature Ross. I had no idea that option was available. I thought it was all electrical, no mechanical. That makes it more appealing. With
mechanical fuel pump only, what kind of performance could one expect from a lycoming IO360 with 9:1 pistons. Can you sustain flight? Or is it just prolong flight?

If you have documention on this feature, could you please send me the link where I can learn more?

Thanks
 
That's a really cool feature Ross. I had no idea that option was available. I thought it was all electrical, no mechanical. That makes it more appealing. With
mechanical fuel pump only, what kind of performance could one expect from a lycoming IO360 with 9:1 pistons. Can you sustain flight? Or is it just prolong flight?

If you have documention on this feature, could you please send me the link where I can learn more?

Thanks

Several single ECU SDS users over the years have devised their own mechanical fuel backups. Usually consists of some fixed orifice nozzles mounted in the intake plenum with a manual fuel valve or solenoid valve to turn on and off fuel. This gives you one power setting with a fixed throttle amount to get back over an airport. You'd size nozzles for the hp level you wanted. This is not something we offer or give design advice on.
 
I'm not sure of the mods done to the pumps, resultant life reduction etc. One is a Sport Class Continental which is a different design than the standard finger drive Lyc pump. I believe the Lyc users have fitted the Lear type rotary pumps.

Plumbing is not really simplified with the mech pump and you still need the bypass regulator to maintain proper differential over MAP for precise metering since pump output exceeds engine usage.

The twin electric pumps have proven to be 100% reliable to date if mounted and filtered as we recommend. The current draw is only a concern if you lose the alternator. We recommend either twin alternators (small vacuum pad one is fine for backup) and/or a backup battery with our EFI systems.

I think the twin alt is the way to go, or use a smaller backup with a load reduction plan for emergency.

In talking with another EFII user who had an alternator failure, even with two batteries, the run time was measured in minutes because of the load of the pumps. I think very prominent annunciation for alternator output drop is a critical thing too.
 
To be fair, the electrical draw is a known value, so if someone has a run time of "minutes", then the batteries were not sized properly to meet requirements. Someone didn't do their homework.

Mine is a VFR airplane and loss of the single alternator is a "land right now" event, despite enough battery capacity to exceed the fuel supply. I know some want enough redundancy to be able to carry on to the destination after a failure, but that's not for me.

There are numerous ways to skin this cat, so it does not surprise me one bit that Ross doesn't want to make a recommendation. But the tools and the methods to make your own determination are out there, and Dan H dragged us through an effective system deconstruction on this very forum recently.
 
Soap box mode ON

I think the twin alt is the way to go, or use a smaller backup with a load reduction plan for emergency.

In talking with another EFII user who had an alternator failure, even with two batteries, the run time was measured in minutes because of the load of the pumps. I think very prominent annunciation for alternator output drop is a critical thing too.

I'm certainly not Ross, but I am installing an engine that will have automotive style injection. I also have had several different 'lives' all related to electronics.

If you're running an electrically dependent engine, there is no good reason to not *know*, within a few minutes, the remaining duration of flight after you lose your electron maker. And there's no good reason to fly a system that can only last 'minutes' (unless that is a significant percentage of an hour) after losing your electron maker.

Know (all) your electrical loads. Know your battery's standby capacity, at required loads (hint: it's never as good as the number on the label). Design so that you can shed loads as required to stay in the air. Test the battery(ies) at reasonable intervals to prove it can still tote the load, for as long as you expect.

Or install a backup electron maker, capable of sourcing enough electrons for your (known) loads.

There's nothing inherently bad (and a lot that's good) about electrically dependent engine control, but if you don't do complete failure analysis, it can drive some bad decisions.
 
Go easy guys. I like a dual battery KIS approach to powering ignitions, but we're talking VFR and 1 amp per sparky thingy. Dual alternators make a lot of sense with large pump draws and a heavy panel. It's not so easy to be sure of full battery capacity all the time, every flight, and IFR might not offer an immediate path to the ground.
 
All good replies here on backup power. If I was flying IFR, I'd have 2 alternators and 2 batteries. On the other hand, I wouldn't fly IFR/ night VFR in a single piston anyway but that's just me.

On a Lycoming with a free vac pad, I'd probably add a small backup alternator there- so easy to do and downsize the backup battery a bit to offset the weight.

We tell people to figure on about 11-12 amps with dual SDS ignition at cruise rpm on a Lycoming four, about 13-14 on a six for one pump, injectors, ECUs and coil packs.
 
Thanks Ross. Sorry if I drifted your thread, but I learned a lot asking those questions.

Looking forward to the next Dave Anders update.
 
Explanation/Plan A

Mark,

Are you asking about a stock engine driven pump? I don't know of any that will approach the 40+ PSI needed for automotive style injectors.

snip

No, I will get a stock TCM pump changed around to produce the proper pressure (50PSI min) and flow (55GPH min) - similar to what Andy Findlay did for his TSIO-550. I won't need quite the pressure and flow that Andy will as I'm only gonna set up for 50"MP.

One of the usual O/H shops told me they could do a similar pump mod using a Romec type pump (vac pad setup), or the pump used on the TSIO 550 that uses a Bendix fuel system (another Romec type pump that actually fits up to the TCM engine). Of course, the Romec can be affixed to the 540 with a change-out to the aft cover.

If using the Romec style pump, plan to use your boost pump when taking off, or landing and taxiing in.

I am thinking of keeping the mags due to the boosted engine - it's gonna have 30"MP where ever I go. That would allow for an emergency fuel nozzle to be placed at the outlet of the supercharger for the one time the electrons decide to bail out. 8-10GPH ought to do the trick if such is actually possible.

BUT! Those electronic ignitions sure do light off the fuel in a hot start situation...

What could possibly go wrong??!!:eek:

Don't worry - I know there are PLENTY of things that could allow me to log some glider time...

Best,
Mark
 
Mark: For what it's worth, I'm flying my AF Performance injected, Lycoming 540 on a Romec vane pump that's been "tuned down" to around 28 gph for takeoff. Seems to work well and yes, I run the boost pump on takeoff and in the pattern. I doesn't need the electric pump just taxiing much of the time but in the summer, especially taxiing in, it sometimes won't run smoothly without it.


Lee...
 
Dave sent me this after the AVC race and Oshkosh in response to questions people asked:

"I have 2 batteries (actually 3 if you count the Skyview back up, but the back ups are small and light) and 1 vacuum pad mounted B&C alternator. It does go into debt below about 1100-1300 RPM. It has a real charge rate of about 24 amps at cruise rpms. It has never been a problem. The back up battery is never used, just checked every time the engine is started. I see you mentioned about a belt breaking and that was my thought when I went to electronic crank timed ignition. The Dynon battery takes care of itself. Even in the Congo line for departure at Oshkosh I had no problems. I just taxied forward put on the brakes and ran an rpm so it was charging a little. There must have been 40 or so planes ahead of me and they were landing inbound planes first and launching the Trimotors ahead of us.

As everyone knows, you worked with me to pair your injection with 2 Lightspeed plasma 3 ignitions. It has worked flawlessly. I use one plasma 3 as the primary SDS source driver and the remaining as the emergency backup, and it is checked before every flight.

That is also how I use your electric fuel pumps. One is primary and the other is only emergency.

I do have a totally separate fuel source if for any reason I lose the injector circuit or ECU or both if I even had a bus failure.

I have a separate fuel line from the your fuel plenum to a fuel solenoid valve on the plenum side of the throttle body behind the butterfly that feeds a 6.3 gph Mister from McMaster Carr, so all I need to stay in the air is 1 working ignition (either), 1 working fuel pump (either) and either the main or backup battery which can be isolated from the main bus.

I have shut down everything in the air and tested the system. It draws about 3 amps at low rpm and at 7500? it trues about 190 mph. At that rate I?ll run a out of fuel before I have to land. Well that may be an exaggeration because I only flew about 100 miles that way and it was doing fine on just the main battery. Of course, the throttle becomes the mixture control. It takes me about 5 seconds now pulling breakers and flipping 2 switches to effect the change and I have practiced that."
 
Some more info from Dave flying back home from Osh:

"This was after leaving Great Falls Montana on the way home. Those are obviously incorrect winds and xw. Then look at 31.4 mpg at this low altitude at about 20” MAP at 2200 rpm, while truing 197mph. I love this system, you can full power or lean with no problems and it starts like a car, even on hot starts."





Dave says he's overcooling in cruise running LOP and will look at reducing the inlet ring size at some point.

The SDS programmer here shows the AFR at 16.7 which is well LOP.
 
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SDS Digital Fuel Flow Accuracy

Some more feedback from Dave today showing the accuracy of our optional FF software. We generate a pulse train from the ECU to feed the engine monitor so no Red Cubes are required.

"Just wanted to let you know that the speed we did in the race was while burning 14.5 gph, confirmed by the max FF indication I was getting when using the SDS fuel signal was within 0.1gph and confirmed by the fuel added at the pump at the pit stop, so at that flow, the FF was accurate to within .227 gals of all the 32 gals in my tanks. During those conditions my engine was producing about 194 real hp at 2830 rpm. Also during the race I burned the left tank out until I saw the fuel pressure fluctuate 2-3 lbs off of max pressure then changed the selector to the tanks without even a hesitation in the engine operation.

hp = 14.5 gph x 5.9 lbs/gal / 0.44 bsfc"
 
FF calc

I have been collecting a lot of data on my install. I do plan to publish it in the future after about 100 hours of use. Currently - at 50 hours - I am consistently within 0.1 gallons at fill up on my IO-390 using the SDSEFI system.
 
Thanks Marvin. Barry will be happy to know all his hard work paid off writing this software. It was dead on in lab testing but nothing like these real world results on running engines to fully confirm.
 
Im very happy to hear the computed fuel flow of the SDS ECU is consistently accurate. I never liked that fuel flow meter clap trap on the engine and especially after Dan dissected one which revealed the miniscule flow passages. Good riddance!

I have just flow tested my new fuel system for the Rocket and am happy to report that it flows 60 GPH with the single pump and 90 with the second running. During the retrofit I went to great lengths to eliminate 90 degree fittings on the suction side, including changing the in tank pickup to a straight fitting. An interesting side note is that I also intended to run two Faccet cube pumps as "pushers" right at the wing roots thinking that my planned use of auto gas would need help to prevent vapor lock. I decided to only install one cube pump for the test period so that I could easily determine if I needed to add the second, or remove the first. During the FF test I noted that the "cube side" sounded more labored than the "non cube side" despite the fact that there was no measurable difference in delivered flow rate. Based upon this, I would not be surprised to find that the added restriction of the cube pump has actually increased my susceptibility to vapor related issues. Testing will determine.

At any rate, the less hardware in the loop, the better! Thanks Ross!
 
Battery Update and Reserve Number Analysis

Dave just installed two Shorai LiFePO4 batteries.

"I decided that I didn't have a long enough reserve capacity in my aux battery. I put in brand new batteries at the time I installed the SDS then put in a larger aux batt when I put the injectors into their new locations on the heads. I looked at the failure voltages of the essential electric components, and the fuel pump is around 9V. Then after looking at the capacity of the aux batt and the voltage decrease as the lead acid battery draws down, I decided that I didn't have enough flying time before i got down to 9V.

With the old system (before i was all electric) I had the Plasma ignitions that would go down to 6V or slightly less. I actually tested that and if I had a total bus failure back then just after take off, I could switch to the aux batt and I would run out of fuel before I lost power to the ignitions. This is not the case now, because as I tested it, my minimum emergency current draw is about 7A.

You may remember that I have the fuel solenoid on the throttle body so all I need is 1 ignition, 1 fuel pump, and that fuel solenoid turned on. Now with the LiFEPO4 36 Ah lead acid equiv aux battery (which isn't really) I can get 1.2 hrs at voltages above 12.8V at a 7A draw.

I can test the batteries individually before I start, to see their voltages, and determine their capacity remaining based on their voltage. The aux batt charges through a Schottky diode so it's not going to get a totally maximum capacity charge but should charge to about 95% of capacity, which would still be enough flying time. If a total main bus and main battery failure occurred in flight, I would have a 320 mile diameter to find a place to land and that would be the worse case scenario. I monitor and alarm the buss minimum/maximum voltages, now set for the LiFePO4 batteries, through my Dynon Skyview.

More likely, an alternator failure may occur and the diameter of the circle increases to about 600 miles because you would use the main batt first. Also with the "indicated voltage/remaining capacity chart" you can actually kind of determine the time remaining as the capacity decreases while the voltage is drawn down.

It took a little work to get the batteries in. I had to reroute fuel lines in the compartment where the batteries are and insulate the batts from the fuselage skin. They were a net 14 lbs lighter."

 
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Dave was the fastest RV at the Airventure Cup race this year, even faster than 2 atmo F1 Rockets. Pretty impressive for a 4 banger. Congrats Dave!
 
I got a message from Dave last week, hadn't heard from him for a while. He's relocated to Arizona from California and been busy with the move.

He said the plane is running fantastic and he loves the efficiency, tunability of individual cylinders and the quick hot starts.
 
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