VansAirForceForums  
Home > VansAirForceForums

- POSTING RULES
- Donate yearly (please).
- Advertise in here!

- Today's Posts | Insert Pics

  #51  
Old 09-01-2017, 07:25 PM
rv7charlie rv7charlie is offline
 
Join Date: May 2006
Location: Pocahontas MS
Posts: 2,331
Default

Quote:
Originally Posted by tspear View Post
No, it is on to on the buy before I start list.
I have reviewed a few excerpts from others who have it.

Tim
Once you get the book and read the subject matter, you'll find that the author has little use for the various electronic bus managers, for a number of (pretty good) reasons.

He also champions the idea that the electrical system should be 'failure tolerant' (my words), in that any single avionics-related failure shouldn't be a reason for early termination of a flight, or even be a cause for alarm. Aircraft equipment and mission define the features (backups) of the avionics and electrical system. A byproduct of this philosophy is that you don't need access to the circuit protection devices in flight, which means that (gasp!) automotive style (ATC) blade fuses work just fine, and are lighter, and radically cheaper than a/c style breakers (a complete set of power supply buses can cost less than a couple of a/c CB's). FWIW, Van's seems to have gotten the memo, with the -12.

My take, and hopefully, worth at least what you paid to read it...

Charlie
Reply With Quote
  #52  
Old 09-01-2017, 09:08 PM
1001001's Avatar
1001001 1001001 is offline
 
Join Date: Dec 2014
Location: Just Minutes from KBVI!
Posts: 654
Default

leok,

I'm planning on using an Arduino for climate control and lighting as well. Do you intend to share your code for the Arduino climate control system? I'd be interested. I was thinking about implementing multi zone temperature control, but am not sure where the temp sensors would best be located (this is way in my future anyway).

I also wanted to do the seat heaters with the Arduino. Basically all comfort-related functions, I planned to do with Arduino, and a Bluetooth dongle to allow a custom phone app to control heat and lighting.
Reply With Quote
  #53  
Old 09-01-2017, 09:09 PM
MCA's Avatar
MCA MCA is offline
 
Join Date: Jun 2005
Posts: 610
Default

You should download and read the VP-X installation manual. Anyone who says it is a single point of failure does not understand it or how it is wired. The manual clearly lays out ways to wire backup circuits for critical devices, and also how to use backup batteries for additional redundancy. Additionally, the VP-X Pro is designed with two independent systems as part of the core architecture. I could go on...

There are always people who want to go old-school and that is fine. But in general, for those with an open mind, I believe new technology has great benefits over old stuff.
__________________
Marc Ausman
RV-7 980 hours, IO-390, VP-X (sold)
RV-8 (flying a friend's)
EAA Director (--> come to Oshkosh in 2018!)

VAF Advertiser - Aircraft Wiring Guide
Book to help with experimental aircraft wiring.
Reply With Quote
  #54  
Old 09-01-2017, 09:32 PM
Mich48041 Mich48041 is offline
 
Join Date: Apr 2008
Location: Riley TWP MI
Posts: 2,523
Default

I agree with Carl and Walt and Charlie. Use circuit breakers or better yet, fuses. It is unlikely they will become obsolete. If they break, the aircraft owner can fix the problem herself without grounding the aircraft. Van's Aircraft put fuses in the RV-12 for a reason. Over 500 are flying.
No doubt the VP-X performs as advertised. But for me, simpler is better and less expensive. I know how to replace a fuse, but do not know how to repair electronics.
__________________
Joe Gores
Reply With Quote
  #55  
Old 09-01-2017, 09:36 PM
tspear tspear is offline
 
Join Date: Nov 2010
Location: Boston Area
Posts: 126
Default

Quote:
Originally Posted by rv7charlie View Post
Once you get the book and read the subject matter, you'll find that the author has little use for the various electronic bus managers, for a number of (pretty good) reasons.....
I have had that impression, based on other comments. My concern about the VPx is more about product longevity.

Quote:
Originally Posted by MCA View Post
You should download ....
There are always people who want to go old-school and that is fine. But in general, for those with an open mind, I believe new technology has great benefits over old stuff.
I like a lot of the VPx fail over, dual bus architecture. I have downloaded and read the manuals, including a lot on the new PPS. However, it has a lot of complexity, for the fault tolerance.

I now waffle mentally if this is over analyzing it. A simple bus bar, with two alternators connected to it and a battery. Set the voltage for the primary alternator a half volt higher then the backup alternator. At startup, turn on the backup alternator first to test it, then the primary alternator. I effectively have a three tier system. Lose the primary alternator, I have to manual drop some load (such as pitot heat), but the system is super simple. Would use stuff that I can almost guarantee to find a replacement for in thirty years.

Like I said, I am still at the waffle stage. I really like ECBs, I like the technology... But sometimes, pure simple just wins.

Tim
Reply With Quote
  #56  
Old 09-01-2017, 10:22 PM
leok leok is offline
 
Join Date: Apr 2013
Location: Clarkston, MI
Posts: 162
Default

I really do appreciate the thoughtful critique of my design. I spent many years as an engineer and engineering manager. I always ran my thoughts by others and encouraged others to do the same. There is no way one person can approach a design from as many angles as a group can. So in that spirit let me give a shot at your comments

Quote:
Originally Posted by 444TX View Post
Nice work with lots of planning. There may be a few gotchas though.

1. BATTERY BUS (SWITCHED). If you are forced to shut of the master in flight you have no power to the bus and lose fuel pump and electronic ignition #1.

Yes, absolutely true. My thinking was that the loss of the master (and/or both alternators) it was time to get on the ground. The fuel pump is backup for the engine driven pump during take off and climb. Not required to get safely on the ground when power is limited to battery. The same for EI #1. EI #2 will get me on the ground. Would I really want to run 2 electronic ignitions when power is limited to what is in the battery? I think this is sound reasoning, but am open to others thoughts.


2. If switching the E-BUS switch from VPX to battery there may be a momentary open that would reset some of the avionics. If done in IFR or an emergency this would not be good. At least test for problems.

The only time I would switch the E-buss on is if both alternators went down or the master relay craped out. Power would already be dead. (I would still have the G5 as it has it's own battery backup.) At that point it is intended to be a fast easy way to unload non-critical items with a single switch.
Garmin allows two power feeds into each instrument separated by internal diodes. Power feed to the instruments is power in #1 through the master/VPX, and power in #2 through the E-buss. You can see that in the pin outs for the critical instrument diagrams. There is no cross talk between the power feeds.
Powering the E-buss all of the time is possible. However, since I have Avionics #1 and the E-buss on the same switch (DP/ST) leaving the E-buss on all of the time is not possible as currently wired. I will think on that one for a while to see if there is a better alternative.


3. Might take the E-BUS backup power feed off the fuse and use the fuse box input stud with a fuse link. Would not use one fuse for so much important stuff. Have seen fuses melt and fuse connections get hot and distorted.

This comment/question has me really thinking. I have the blade fuse in the rear behind the rear bulkhead. If I used a resettable breaker on the IP I could at least bring back some power if the breaker tripped. It would really be a bad day if I lost both alternators and then popped the E-buss. All I would have left at that point is the G5 and no EI ...... that needs some rethinking!!

I had been considering that I needed to move at least one of the ignitions to a direct battery feed based on reading the Light Speed Ignition installation manual. The ignitions are one thing I do not have wired yet since I haven't purchased the engine. So easy to change.

Thank you for your comment!


4. 7 SWITCHES. Three are down on and four are up on. The aircraft standard is all down for off and up for on. I see what you may be doing and it is you who is flying your design, but non standard can cause confusion issues when emergency decisions are made. Would recommend consistency.

Here is the thought process. (Page 19 of the power point is the switch group in question) In the normal run/cruse condition all switches are up. The bottom row is all on, the top row is all off. They are rocker switches that show red when down, so in normal run no red shows. If any switch is pushed to the down position, it is an abnormal situation and red shows on the top of the switch. i.e. boost fuel pump on is down (showing red) reminding me to turn it off as appropriate.
Again, my logic tells me this is simple and appropriate. As always I am open to other thoughts.

5. I would remove the G5 from any external bus inputs to keep true independence. A single point failure could take out the entire set of Garmin flight instruments. I know that the Garmin experts say it can/will not happen, but do you want to bet your life on it flying IFR. True independent redundancy would be preferred.

The G5 connection to the system is through the CAN buss. Physical damage to the CAN buss wiring/daisy chain can take the buss down. However communication is based on packets of info being transmitted with appropriate headers. The loss of the CAN buss or corrupt information on the buss have no effect on other buss devices. This is the same buss technology that has been used in automobiles for about 50 years.
MY larger concern is that by taking the G5 off the buss you loose all of the backup functions available from the G5 which are GPS, AHRS, and auto pilot functionality.

A single large diagram of all the power circuits may find other small potential problem areas. A lot is riding on the VPX. Hope it is reliable and glitch free.

I don't disagree here on the VPX. I would really be bummed if ever had to rip it out and reconfigure to a conventional power system.
I do like what I have, and think I have a reasonably well thought out implementation plan. I like the flexibility and diagnostic capability and think it a good trade off. I also like solid state components.
I appreciate the comment on one large diagram. The (virtual) paper I have been working with, as well as my evolving thought processes led to several smaller diagrams. What is important is that I can find and identify every wire from the diagrams. In the spread sheet, I also listed what is on each buss so I can see the overview there.

One last comment: I am close to a finished plan for my specific aircraft, but am always open to thoughtful feedback. Usual disclaimers, I do not suggest this is appropriate in whole or part for anyone else's project. I will be testing and looking for issues before and well into flying. I will try to follow up in this thread over time.

George
__________________
Building my RV-10 since Oct 5th 2014
Flying .. once I figure out how to pay for everything
http://www.mykitlog.com/leok
RV Hotel
Dues paid 2017

Last edited by leok : 09-28-2017 at 01:53 AM. Reason: add color to text
Reply With Quote
  #57  
Old 09-01-2017, 10:50 PM
leok leok is offline
 
Join Date: Apr 2013
Location: Clarkston, MI
Posts: 162
Default

Quote:
Originally Posted by tspear View Post
Here is a question I was asked this week, and I do not have a good answer.
I would like to use VPx, but in the last ten years they have had multiple model changes.
My next plane will be my last plane, and I hope to fly for thirty more years.
So, if you plan to fly for a long time, do you treat the VPx like your avionics and plan to replace it? Or do you abandon such advanced technology and go with simple single pole circuit breakers which have been the same for forty years and will likely still be the same in another forty?

Tim
My response to your comments is that early adopters are often stranded with obsolete products. Fast model changes are a fact of innovation with fast moving development. The question in my mind is are we far enough into this technology that changes will come less frequently and will VPX stick with the current product for a long time. Or at least consider backward compatibility with the next offering.

I don't see ECBs becoming obsolete. Only time will tell on the current VPX offerings.

I also see no reason to attempt to change anybody's mind. As stated elsewhere, if you see no value in the added features of the VPX don't get one. If you do find the features compelling, and plan to use them, the money difference is not that great after you piece together a conventional system.

I do (with respect) challenge the refrain "single point failure" as used in the context of the VPX. If I understand the architecture of the VPX Pro properly, there are two fully separate internal electronic busses. Other than one power wire attaching to the box, there is no "single" failure that would take the VPX completely out.
Good planning will split redundant critical functions between these. I also don't feel that I have spent any significant money, only thought, logic and a few wires to add layers of redundancy while incorporating the VPX Pro. I'm not trying to be a pain here, just accurate. Please correct me if you think I am wrong.
__________________
Building my RV-10 since Oct 5th 2014
Flying .. once I figure out how to pay for everything
http://www.mykitlog.com/leok
RV Hotel
Dues paid 2017
Reply With Quote
  #58  
Old 09-02-2017, 07:38 AM
leok leok is offline
 
Join Date: Apr 2013
Location: Clarkston, MI
Posts: 162
Default

Quote:
Originally Posted by 1001001 View Post
leok,

I'm planning on using an Arduino for climate control and lighting as well. Do you intend to share your code for the Arduino climate control system? I'd be interested. I was thinking about implementing multi zone temperature control, but am not sure where the temp sensors would best be located (this is way in my future anyway).

I also wanted to do the seat heaters with the Arduino. Basically all comfort-related functions, I planned to do with Arduino, and a Bluetooth dongle to allow a custom phone app to control heat and lighting.

Sure, no problem, here is the link to the program file:

https://drive.google.com/file/d/0BxZ...ew?usp=sharing

Just a few comments; The YouTube series by Paul McWhorter is excellent instruction on how to program the little beast. https://www.youtube.com/channel/UCfY...ZTpNFrc_NDKfTA

He is a school teacher in Texas, and does a great job in explaining the programming. I found tuning the end points of the movement to be an iterative process. You don't want the servos to be in a stalled condition at the end of movement. The numbers in my program will not likely work in anyone else's. I used 1K pots for my control. If you use other values the numbers would also have to change. Without a shield, a single Arduino can control up to 6 servos. I have seen shields that will handle up to 12. I also added a connection shield to mine as it has better wire attach points and a breadboard where I could add the power circuit to drive the servos in a nice neat package.

The addition of climate control should be an easy thing with a little playing around. All you would have to do is tie a thermistor into the servo position loop. Oh, and also find a position in the aircraft to place the thermistor that gave reasonable performance. I do plan on playing with that some time in the future ... maybe.

So good luck. I would like to hear how it goes.
__________________
Building my RV-10 since Oct 5th 2014
Flying .. once I figure out how to pay for everything
http://www.mykitlog.com/leok
RV Hotel
Dues paid 2017
Reply With Quote
  #59  
Old 09-02-2017, 07:45 AM
leok leok is offline
 
Join Date: Apr 2013
Location: Clarkston, MI
Posts: 162
Default

Quote:
Originally Posted by PilotjohnS View Post
Now you got me thinking about a VPX. This could get expensive. Especially if you tell me the VPX sends data to the G3X over the CANbus.
Well sorta, there is a RS232 link (not CAN) to the G3X. Control of the electrical (on/off) can be done on screen or through a physical switch.
__________________
Building my RV-10 since Oct 5th 2014
Flying .. once I figure out how to pay for everything
http://www.mykitlog.com/leok
RV Hotel
Dues paid 2017
Reply With Quote
  #60  
Old 09-02-2017, 07:58 AM
1001001's Avatar
1001001 1001001 is offline
 
Join Date: Dec 2014
Location: Just Minutes from KBVI!
Posts: 654
Default

Thanks very much!

I used an Arduino a few years ago to semi-automate a small (10-gal) brewery. I started off with it doing temperature control for the mash. there was a PID controller library that someone wrote that I used. It worked pretty well in testing. I ended up mostly running the brewery manually because I wanted to make beer more than I wanted to spend time automating the system, but I still have a couple of Arduino boards and plenty of accessories sitting around. I also got a bluetooth serial link running with a basic Android app to monitor the temperatures and set the setpoint, so I have the basics of what I want to do with the airplane complete. Once I have my project ready to go, I intend to share the code.

I don't want to put any safety related or high-current systems on the Arduino itself (even with a relay breakout board), so if I go with a VPX, I will just use the Arduino to send signals to the VPX for things like seat heaters and maybe cowl interior temp control (if I go with cowl flaps). Lighting and climate control will be via a relay board with an option to override critical lights like panel and pilot map illumination. Nav lights and strobes will be strictly through the main power system, probably.


Quote:
Originally Posted by leok View Post
Sure, no problem, here is the link to the program file:

https://drive.google.com/file/d/0BxZ...ew?usp=sharing

Just a few comments; The YouTube series by Paul McWhorter is excellent instruction on how to program the little beast. https://www.youtube.com/channel/UCfY...ZTpNFrc_NDKfTA

He is a school teacher in Texas, and does a great job in explaining the programming. I found tuning the end points of the movement to be an iterative process. You don't want the servos to be in a stalled condition at the end of movement. The numbers in my program will not likely work in anyone else's. I used 1K pots for my control. If you use other values the numbers would also have to change. Without a shield, a single Arduino can control up to 6 servos. I have seen shields that will handle up to 12. I also added a connection shield to mine as it has better wire attach points and a breadboard where I could add the power circuit to drive the servos in a nice neat package.

The addition of climate control should be an easy thing with a little playing around. All you would have to do is tie a thermistor into the servo position loop. Oh, and also find a position in the aircraft to place the thermistor that gave reasonable performance. I do plan on playing with that some time in the future ... maybe.

So good luck. I would like to hear how it goes.
Reply With Quote
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump


All times are GMT -6. The time now is 07:48 PM.


The VAFForums come to you courtesy Delta Romeo, LLC. By viewing and participating in them you agree to build your plane using standardized methods and practices and to fly it safely and in accordance with the laws governing the country you are located in.