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  #31  
Old 08-06-2016, 07:48 PM
gasman gasman is offline
 
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Isn't Dave still using dual Lightspeed ignition?
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  #32  
Old 08-06-2016, 08:09 PM
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Quote:
Originally Posted by DanH View Post
...at 17,500, with a clean RV-4. Excellent numbers for sure, but it's important to maintain perspective.

Very few of us have an personal data at 17,500. Let's go back to the previous post for something more typical.



Ok, so Dave reports 174 knots on 6.8 with the small RV-4 airframe and a modified 360.

Here's a clean RV-8, dead stock 390 with Slicks and AFP constant flow, similar altitude....hauling camping gear, clothes, and three half-cases of Spotted Cow back from OSH. 178 knots on 7.8:



25~30 LOP was the limits of smoothness with the Slicks, which is why I'm now converting to EI. Go a bit leaner, and the airplane will slow down and burn a little less fuel, closing the gap on that 174/6.8 benchmark. The catch will be mixture distribution with 0.028 restrictors as fuel flow drops closer to 7, and the flow divider starts playing a larger role in cylinder balance. Without question, the SDS EFI will maintain superior balance at very low flows, in particular with the new on-the-fly balancing capability.
And then here is a quote from the RV12 page......... "I just looked again at a D180 screen shot from the trip. 7500', OAT 18C, DA 9690, 22.3" MAP. The TAS was 119 knots, 5380 RPM and burning close to 7 GPH."
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  #33  
Old 08-07-2016, 08:52 AM
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rv6ejguy rv6ejguy is offline
 
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Quote:
Originally Posted by gasman View Post
Isn't Dave still using dual Lightspeed ignition?
Yup, he has the knob dial timing function so he can play with it in flight.
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Ross Farnham, Calgary, Alberta
Turbo Subaru EJ22, SDS EFI, Marcotte M-300, IVO, Shorai- RV6A C-GVZX flying from CYBW since 2003- 441.0 hrs. on the Hobbs,
RV10 95% built- Sold 2016
http://www.sdsefi.com/aircraft.html
http://sdsefi.com/cpi2.htm


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  #34  
Old 08-07-2016, 08:54 AM
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rv6ejguy rv6ejguy is offline
 
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Your numbers are very impressive too Dan. Your -8 looks very slick in the photos and you've got that proper cowl flap and exit on there which we know helps a few more knots.

I guess I was more impressed with the 4.8/ 158 KTAS part. Doubt any other RV equipped with mechanical FI and mags will come close to that.
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Ross Farnham, Calgary, Alberta
Turbo Subaru EJ22, SDS EFI, Marcotte M-300, IVO, Shorai- RV6A C-GVZX flying from CYBW since 2003- 441.0 hrs. on the Hobbs,
RV10 95% built- Sold 2016
http://www.sdsefi.com/aircraft.html
http://sdsefi.com/cpi2.htm



Last edited by rv6ejguy : 08-07-2016 at 09:01 AM.
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  #35  
Old 08-07-2016, 10:40 AM
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DanH DanH is offline
 
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Quote:
Originally Posted by rv6ejguy View Post
Your -8 looks very slick...
Not as slick as Dave's RV-4. Larger too.

Readers unfamiliar with Dave Anders may enjoy this CAFE Foundation report from the January 1998 issue of Sport Aviation. If this link doesn't work, log in at eaa.org and use the publications search function.

file:///C:/Users/wks/Downloads/Article-10152.pdf

Quote:
I guess I was more impressed with the 4.8/ 158 KTAS part. Doubt any other RV equipped with mechanical FI and mags will come close to that.
Yeah, and Seabiscuit was a fast horse because he drank beer
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  #36  
Old 08-07-2016, 06:20 PM
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rv6ejguy rv6ejguy is offline
 
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Quote:
Originally Posted by DanH View Post
Not as slick as Dave's RV-4. Larger too.

Readers unfamiliar with Dave Anders may enjoy this CAFE Foundation report from the January 1998 issue of Sport Aviation. If this link doesn't work, log in at eaa.org and use the publications search function.

file:///C:/Users/wks/Downloads/Article-10152.pdf



Yeah, and Seabiscuit was a fast horse because he drank beer
I think Dave has some more wing than you. That may actually be helping him up high. In any case, Dave's always willing to put his plane in a side by side with anyone who's curious and in his locale.

There should be a new article upcoming in Kitplanes on Dave's RV-4 journey a few months down the road too.
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Ross Farnham, Calgary, Alberta
Turbo Subaru EJ22, SDS EFI, Marcotte M-300, IVO, Shorai- RV6A C-GVZX flying from CYBW since 2003- 441.0 hrs. on the Hobbs,
RV10 95% built- Sold 2016
http://www.sdsefi.com/aircraft.html
http://sdsefi.com/cpi2.htm


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  #37  
Old 08-08-2016, 07:41 AM
Don at Airflow Don at Airflow is offline
 
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Not to hijack the EFI glory, but here is a set of flight test data on a IO-340. While this customer was not looking for flying high LOP he was interested in going fast WOT low altitude. A box stock RV-6, standard Vans cowl, up draft sump, Vetterman cross over exhaust. This is with an Airflow Performance FM-150L Mechanical constant flow fuel injection system with one P-mag and one electronic ignition, and 9:1 compression.

WOT Take Off 2700 RPM, Fuel Flow 15.1 GPH, 29.7? MAP (MAP before engine start 30.2?)

3500 Feet, 2400 RPM, 24? MAP
Full Rich Fuel Flow10.5 GPH, EGT/CHT #1 1214/343, #2 1261/335, #3 1217/343, #4 1238/336
All cylinders peaked at 7.7 GPH with EGT #1 1412, #2 1465, #3 1428, #4 1452
The fuel rich fuel air ratio .086 (AF 11.6). Peak EGT fuel air ratio .065 (AF 15.4)
GAMI spread <0.1 GPH. CHT spread 8 degrees F

3500 Feet, 2500 RPM, 22? MAP
All cylinders peaked at 7.2 GPH with EGT #1 1431, #2 1478, #3 1445, #4 1468
GAMI spread <0.1 GPH

8500 Feet, 2500 RPM, 22? MAP
All cylinders peaked 7.8 GPH with EGT #1 1412, #2 1457, #3 1418, #4 1452
GAMI spread <0.1 GPH
LOP operation engine smooth 6.5 GPH with EGT #1 1280, #2 1309, #3 1294, #4 1309
Running approximately 125 degrees LOP with smooth engine operation the fuel air ratio was approximately .055 (AF 18.2)

Again not set up for efficiency but at 3300 feet ,2650 RPM, 22? MAP and 10.5 GPH, speed was 162 MPH.
All with old school mechanical fuel injection, no computers, no O2 sensors, no tuned intake pipes or plenum, no 4 into one tuned exhaust, no pressure cowling.
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  #38  
Old 08-08-2016, 09:17 AM
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rv6ejguy rv6ejguy is offline
 
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Quote:
Originally Posted by Don at Airflow View Post
Not to hijack the EFI glory, but here is a set of flight test data on a IO-340. While this customer was not looking for flying high LOP he was interested in going fast WOT low altitude. A box stock RV-6, standard Vans cowl, up draft sump, Vetterman cross over exhaust. This is with an Airflow Performance FM-150L Mechanical constant flow fuel injection system with one P-mag and one electronic ignition, and 9:1 compression.

WOT Take Off 2700 RPM, Fuel Flow 15.1 GPH, 29.7? MAP (MAP before engine start 30.2?)

3500 Feet, 2400 RPM, 24? MAP
Full Rich Fuel Flow10.5 GPH, EGT/CHT #1 1214/343, #2 1261/335, #3 1217/343, #4 1238/336
All cylinders peaked at 7.7 GPH with EGT #1 1412, #2 1465, #3 1428, #4 1452
The fuel rich fuel air ratio .086 (AF 11.6). Peak EGT fuel air ratio .065 (AF 15.4)
GAMI spread <0.1 GPH. CHT spread 8 degrees F

3500 Feet, 2500 RPM, 22? MAP
All cylinders peaked at 7.2 GPH with EGT #1 1431, #2 1478, #3 1445, #4 1468
GAMI spread <0.1 GPH

8500 Feet, 2500 RPM, 22? MAP
All cylinders peaked 7.8 GPH with EGT #1 1412, #2 1457, #3 1418, #4 1452
GAMI spread <0.1 GPH
LOP operation engine smooth 6.5 GPH with EGT #1 1280, #2 1309, #3 1294, #4 1309
Running approximately 125 degrees LOP with smooth engine operation the fuel air ratio was approximately .055 (AF 18.2)

Again not set up for efficiency but at 3300 feet ,2650 RPM, 22? MAP and 10.5 GPH, speed was 162 MPH.
All with old school mechanical fuel injection, no computers, no O2 sensors, no tuned intake pipes or plenum, no 4 into one tuned exhaust, no pressure cowling.
The GAMI spreads here are very good but all at about the same rpms. I've had many mechanical FI users tell me- yes spreads can be very good if they cruise near the same rpms but often not good if they really drop the rpms and fly high. The point is that the EFI can have zero GAMI spread everywhere from 2000 to 2700 rpm and any altitude with any manifold pressure and any intake manifold, no screwing around changing nozzles trying to find the best compromise, no more hot or cold start issues, no more rough idle issues.

WOT, low altitude power is relatively easy and the EFI can do that well too.

The reason why Dave switched from mechanical FI was exactly this since he flies at all different altitudes and power settings. He wasn't satisfied with the mechanical injection. You can read his own comments in this thread.

Technology marches on and we see all new aviation engine manufacturers equipping their engines with EFI, not mechanical injection- Rotax, D-Motor, UL Power, Adept Airmotive etc.

Lycoming, Continental and Jabiru users are seeing the same benefits with EFI over legacy engine controls.

For many new builders, carbs, mags and mechanical FI are heading the same way as steam gauges in Experimental aircraft.
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Ross Farnham, Calgary, Alberta
Turbo Subaru EJ22, SDS EFI, Marcotte M-300, IVO, Shorai- RV6A C-GVZX flying from CYBW since 2003- 441.0 hrs. on the Hobbs,
RV10 95% built- Sold 2016
http://www.sdsefi.com/aircraft.html
http://sdsefi.com/cpi2.htm


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  #39  
Old 08-08-2016, 10:04 AM
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DanH DanH is offline
 
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I suspect this debate will be going on a long time

I am sure Anders likes the EFI system. With the new on-the-fly fuel trim, it can be tweaked to a zero GAMI spread at very low flows, something current constant flow systems can't do. Heck, I like that detail, and I'm very much in the KIS mindset. Who can resist perfect, even when there might not be a practical reason for it?

In terms of absolute numbers, it might be misleading to claim this RV-4's efficiency is due to EFI. Dave has been working on efficiency since he built the airplane, something like 25 or 30 years ago. It's simply a very efficient airplane. Here EFI is allowing the exploration of remote corners of the flight envelope. Such performance delights the experimenter, but frankly, very few RV owners have reason to care about low fuel flow at 17,500 feet. As we've seen, constant flow gets pretty close to the same numbers at common altitudes and power settings.

Hot starts and hot idle? Point to EFI. Simplicity, not electrically dependent? Point to constant flow. Right now it pretty much a draw, with choice going on what the buyer values most.

To Ross's point about the future, yes, EFI is the future, but perhaps not this EFI, which is actually quite old on the technology scale. When we start burning unleaded, and can go to closed loop control with an integrated spark and FI map, well, then aircraft EFI will enter the 21st century.
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  #40  
Old 08-08-2016, 10:39 AM
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rv6ejguy rv6ejguy is offline
 
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Quote:
Originally Posted by DanH View Post
I suspect this debate will be going on a long time

I am sure Anders likes the EFI system. With the new on-the-fly fuel trim, it can be tweaked to a zero GAMI spread at very low flows, something current constant flow systems can't do. Heck, I like that detail, and I'm very much in the KIS mindset. Who can resist perfect, even when there might not be a practical reason for it?

In terms of absolute numbers, it might be misleading to claim this RV-4's efficiency is due to EFI. Dave has been working on efficiency since he built the airplane, something like 25 or 30 years ago. It's simply a very efficient airplane. Here EFI is allowing the exploration of remote corners of the flight envelope. Such performance delights the experimenter, but frankly, very few RV owners have reason to care about low fuel flow at 17,500 feet. As we've seen, constant flow gets pretty close to the same numbers at common altitudes and power settings.

Hot starts and hot idle? Point to EFI. Simplicity, not electrically dependent? Point to constant flow. Right now it pretty much a draw, with choice going on what the buyer values most.

To Ross's point about the future, yes, EFI is the future, but perhaps not this EFI, which is actually quite old on the technology scale. When we start burning unleaded, and can go to closed loop control with an integrated spark and FI map, well, then aircraft EFI will enter the 21st century.
Never claimed the EFI was completely responsible for the numbers Dave is seeing. It certainly isn't. As you correctly state, Dave's airplane has been aerodynamically refined for many years along with the engine mods by Lycon. The first post in this thread covers Dave's initial observations of the EFI vs. the mechanical FI and yes, you're correct, the mechanical FI can deliver very good numbers within a narrower "more normal" cruise range as we've seen this many times.

You might be surprised how many folks fly high with O2. Certainly not over 15% in my estimation but quite a number. Lots do fly at 10-12K though. I think showing what can be done up high might make more people try that, at least below O2 levels.

I agree too on your point that one product does not fit all needs or missions or wants so it's good that people have more choices now.

As far as electrical needs, yes EFI needs that but these days many Experimentals already have a backup power source for the glass panel anyway. This fact does not make many decide to put steam gauges in any more however.

You are right again about this EFI being somewhat low tech compared to what the automakers are using today and the reason is mainly the leaded fuel. However, we have had closed loop technology now for over 20 years in the SDS product line and when unleaded avgas is introduced, people will already be set up to take full advantage of that feature too. We tested targeted AFR software 10 years ago in Florida on an RV and it was pretty magic. That's easily implemented with a reflash to current ECUs.

With this, we could also change ignition timing automatically with AFR and load, bringing our capabilities closer in line with the latest auto technology.
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Ross Farnham, Calgary, Alberta
Turbo Subaru EJ22, SDS EFI, Marcotte M-300, IVO, Shorai- RV6A C-GVZX flying from CYBW since 2003- 441.0 hrs. on the Hobbs,
RV10 95% built- Sold 2016
http://www.sdsefi.com/aircraft.html
http://sdsefi.com/cpi2.htm



Last edited by rv6ejguy : 08-08-2016 at 01:03 PM.
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