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  #21  
Old 03-15-2018, 12:40 PM
Patrick14 Patrick14 is offline
 
Join Date: Feb 2018
Location: Mainz, Germany
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Quote:
Originally Posted by rv6ejguy View Post

Propeller control would add a lot of cost and at least one more year of development time and validation testing to make happen. Many prefer to leave the prop control manual. I don't see that one in the cards for us.
Dear Ross, thank you for quick the reply!
An automatic prop control would need at least manifold pressure and rpm inputs, which are available by the EFI. It would be nice to make them accessible via a port, interface or bus. So a third party company could develope a prop control device which might be programmable or just follows an adapted MP-RPM squared or similar.
One could use it or not.

best regards

Patrick

Last edited by Patrick14 : 03-15-2018 at 12:42 PM.
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  #22  
Old 03-15-2018, 05:20 PM
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rv6ejguy rv6ejguy is offline
 
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We can currently output serial sensor and cpu data from the EM-5 and this will be expanded more on the EM-6.

Someone could use this data to run a prop controller. We don't have the time, money or ability to test for that aspect but we could share the info if someone was serious about designing such a prop controller.

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Ross Farnham, Calgary, Alberta
Turbo Subaru EJ22, Marcotte M-300, IVO, RV6A C-GVZX flying from CYBW since 2003- 419.2 hrs. on the Hobbs,
RV10 95% built- Sold 2016
http://www.sdsefi.com/aircraft.html
http://sdsefi.com/cpi.htm



Last edited by rv6ejguy : 03-15-2018 at 05:29 PM.
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  #23  
Old 03-15-2018, 05:32 PM
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rv6ejguy rv6ejguy is offline
 
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Quote:
Originally Posted by Patrick14 View Post
The FADECs/ECUs i worked with over the last 20 years (CFM, RR, PW, IAE) were working pretty stable and helped a lot against mishandling of the engine. The backup modes for a minor failure (sensor fault or similar) do not neccessarily cause a thrust reduction to idle. If a modern intelligent ignition and fuel management helps to keep the pre WWII technology lycoming and continentals within their healthy envelopes, it may also save us from mechanical failures later on.
I think he was referring to the fact that many OEM auto ECUs command low power or complete engine shutdown to save the engine in the event of certain sensor failures or out of range engine parameters.
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Ross Farnham, Calgary, Alberta
Turbo Subaru EJ22, Marcotte M-300, IVO, RV6A C-GVZX flying from CYBW since 2003- 419.2 hrs. on the Hobbs,
RV10 95% built- Sold 2016
http://www.sdsefi.com/aircraft.html
http://sdsefi.com/cpi.htm


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  #24  
Old 03-17-2018, 02:40 PM
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czechsix czechsix is offline
 
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Location: Spring Hill, KS
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Quote:
Originally Posted by Toobuilder View Post
Your panel looks fantastic, but for clarity the switches you have shown are personal choice - not "required". For example, I do not power my ECU's independantly, nor do I have a separate switch for the fuel pumps. I have a single "Engine On/Off" switch, and the Pri/Sec. The engine switch powers both ECU's, the coils, and a single fuel pump. Just like a car. My second fuel pump is in my old "boost pump" location on the throttle, and it is used exactly as we have been trained for generations: takeoff, landing, and "as required". There are many ways to skin this cat and personal choice is going to dictate what we are comfortable with.
I've been thinking a lot about switch configurations for the EFI system in my RV-14A. A few years ago I had the opportunity to spend a dozen hours flying an RV-12, and it really struck me how simple the airplane was to operate. There's no mixture or prop levers, no fuel selector, and the boost pump and nav lights came on with the master switch. For takeoff and landing it was just throttle and flaps!

So back to the EFI switching scheme, I'm thinking about having just two switches. The left switch would be DPDT with one circuit controlling power to ECU A, Coilpack1, and Pump1 and the second circuit controlling injector selection (injectors would be using ECU A when this switch is On and switch to ECU B when Off). The right switch would be SPST controlling power to ECU B, Coilpack2, and Pump2.

This really reduces the proliferation of switches related to the ignition/EFI from seven down to two. You can do a standard 'mag check' on run-up where you turn off one side of the system and verify that the engine runs on the other. If you have an engine problem in flight, you switch tanks and turn Off the left switch (because this moves injectors from ECU A to B). A bit unconventional perhaps but very simple and the left switch would be clearly marked (yellow) for this function.

Downsides would include running both fuel pumps all the time (don't know if this would substantially reduce reliability of the pumps, it would mean pulling another 4.5 A continuously but I'm planning dual alternators so not really worried about the electrical load). Also the left switch becomes a single point failure for the engine since it controls power to one side of the system AND switches injectors between ECUs...but I think it would be a very unlikely failure mode where one circuit of the DPDT switch fails open (loss of power to ECU A/coilpack1/Pump1) and the other circuit fails to actuate when you flip the switch off to move the injectors to ECU B. And if this failure mode is even possible, it would most likely happen when actuating the switch at the beginning or end of the flight, and not during flight when you would not normally be touching the switch.

One other downside to ganging everything together is troubleshooting...if something isn't working, it's a bit less obvious who the culprit is. The fuel pumps could be ruled out by looking at fuel pressure, so it would mainly be a question of ECU vs coil pack.

Has anybody used a switching scheme like this?
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Spring Hill, KS
RV-8A N2D #80583 - built/flew/sold
RV-14A #140017 - wings complete, empacone in progress...

Last edited by czechsix : 03-18-2018 at 09:50 PM. Reason: minor wording clarification
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  #25  
Old 03-23-2018, 05:34 AM
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rv6ejguy rv6ejguy is offline
 
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I want to thank the people who've commented and sent us ideas for the EM-6. We've got plenty to work on for sure and we've compiled "The List" now.

Spent a lot of evening hours evaluating displays lately and we'll be ordering some samples soon to see which way we want to head there.

Looking forward to the new design challenge in the coming months.
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Ross Farnham, Calgary, Alberta
Turbo Subaru EJ22, Marcotte M-300, IVO, RV6A C-GVZX flying from CYBW since 2003- 419.2 hrs. on the Hobbs,
RV10 95% built- Sold 2016
http://www.sdsefi.com/aircraft.html
http://sdsefi.com/cpi.htm


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  #26  
Old 03-25-2018, 03:51 PM
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rv6ejguy rv6ejguy is offline
 
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Default Panel Planning

Evaluation work is slowly starting to proceed on the EM-6 now.

We've had a number of requests about what type of display we'll use on the EM-6. Can't really say much at this time but I'd plan to allow 5 X 4 inches of front panel real estate for it.
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Ross Farnham, Calgary, Alberta
Turbo Subaru EJ22, Marcotte M-300, IVO, RV6A C-GVZX flying from CYBW since 2003- 419.2 hrs. on the Hobbs,
RV10 95% built- Sold 2016
http://www.sdsefi.com/aircraft.html
http://sdsefi.com/cpi.htm



Last edited by rv6ejguy : 03-25-2018 at 04:10 PM.
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  #27  
Old 03-26-2018, 11:31 AM
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czechsix czechsix is offline
 
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Quote:
Originally Posted by rv6ejguy View Post
We've had a number of requests about what type of display we'll use on the EM-6. Can't really say much at this time but I'd plan to allow 5 X 4 inches of front panel real estate for it.
Ross, the RV-14 I'm building has a larger panel than most of the RVs (other than the -10) and 5x4 is going to be hard to find space for in my panel layout with dual G3X displays, an IFR stack in the middle, and G5 on one side. I'd much prefer a footprint that will mount in a 3 1/8" hole like the EM-5 control head. Ok if the bezel is in front of the panel and extends a bit beyond the hole, but 5x4 is going to tough to fit.

Might be a good idea to make sure those dimensions will work for the majority of your customers before committing...

Thanks,
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Mark Navratil
Spring Hill, KS
RV-8A N2D #80583 - built/flew/sold
RV-14A #140017 - wings complete, empacone in progress...
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  #28  
Old 03-26-2018, 12:36 PM
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rv6ejguy rv6ejguy is offline
 
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It's a case of not being able to please everyone unfortunately. Some want a 2.25 inch display but it becomes too small to use and display anything usefully.

We may continue to offer the current 3 1/8 round programmer for those with limited panel space as well as the newer, larger one. Not as flashy but perfectly functional.

We don't have plans to develop two new displays of different sizes however which would be too expensive and time consuming.

The 5 X 4 is not set in stone yet but looks like we're headed that way at this time. We'd have liked to integrate with the popular EFIS' but one manufacturer questions the amount of units they would sell configured to control SDS and whether they could justify the engineering time to expend in that direction. I understand that. If we can't do it with both of the big 2, it won't fly.
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Ross Farnham, Calgary, Alberta
Turbo Subaru EJ22, Marcotte M-300, IVO, RV6A C-GVZX flying from CYBW since 2003- 419.2 hrs. on the Hobbs,
RV10 95% built- Sold 2016
http://www.sdsefi.com/aircraft.html
http://sdsefi.com/cpi.htm



Last edited by rv6ejguy : 03-26-2018 at 12:42 PM.
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  #29  
Old 03-26-2018, 05:17 PM
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Larry DeCamp Larry DeCamp is offline
 
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Default Fuel pump duty cycle question

Ross, The question was raised above if continuous use of both pumps should be any consideration on an EFI system. Your experience with cars and planes would be appreciated. The proposed simple system above has merit if two pumps running 100% is a non issue.
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RV-4 fastback w/ Superior EXP 0360 /AFP & CPI
Clinton, IN
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  #30  
Old 03-26-2018, 06:45 PM
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rv6ejguy rv6ejguy is offline
 
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I've had this question a few times lately.

Depending on the pumps and regulator used, we usually see a 1-9 psi pressure rise at idle with both pumps running. This is a function of flow rate, return volume, base pressure setting and regulator orifice area.

Fuel flow changes as the square of the pressure so when we're talking 40-50 psi base pressures, a rise of 9 psi will richen the AFRs somewhat at idle but have less effect at WOT/ high power settings where the return flow is considerably less. A 2 psi change would not be very significant. Return flow is roughly 99% at idle (engine burning 1% of the total pump flow).

The standard pumps we use in most Lycoming installations output around 50 gal./hr ea. X 2= 100GPH.

The drawbacks to using both pumps continuously would be extra heating of the fuel, some loss in metering accuracy over the whole range of power settings as the regulator may not be capable of accurately maintaining the differential pressure over MAP, using double the current as one and possibly not knowing if one pump fails.

Be sure to shed the load from the other pump if you have an alternator go down though as the pumps are big current hogs (4.5-5.5 amps at usual pressures)

Main advantage of using both would be the engine would keep running if one failed with no pilot intervention.

Our experience with these pumps is that they are extremely reliable if mounted as we recommend. I personally put over 5000 hours on one of these in our shop car over 18 years. We've also sold hundreds of them and never had a legitimate warranty claim yet (2 failed in a few hours when mounted improperly with inlet ports facing upwards vertically). Put proper filtration on them too. We supply a large 40 micron inlet filter on the 2018 kits now.

It's well down my list of things to worry about in my aircraft so I use one at a time- pump 1 on odd days, pump 2 on even days. If you prefer to run them both at the same time, I see no big issues with that, just be aware of the things I listed above.
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Ross Farnham, Calgary, Alberta
Turbo Subaru EJ22, Marcotte M-300, IVO, RV6A C-GVZX flying from CYBW since 2003- 419.2 hrs. on the Hobbs,
RV10 95% built- Sold 2016
http://www.sdsefi.com/aircraft.html
http://sdsefi.com/cpi.htm


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