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03-31-2019, 01:52 PM
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Join Date: Jun 2006
Location: 8I3
Posts: 3,564
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Quote:
Originally Posted by Walt
an unplanned short to one of these 'hot busses' can have serious consequences (I've seen it happen).
If you don't think one wire can create enough smoke/heat to cause a fire maybe you should try it.
Nothing worse than an electrical short that you can't shut off, all you can do is watch it burn.
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Walt is absolutely correct here.
A cell short in one of the batteries, game over. I've had a battery in my Jeep die in this manner and could not jump start it.
__________________
Please don't PM me! Email only!
Bob Japundza CFI A&PIA
N9187P PA-24-260B Comanche, flying
N678X F1 Rocket, under const.
N244BJ RV-6 "victim of SNF tornado" 1200+ hrs, rebuilding
N8155F C150 flying
N7925P PA-24-250 Comanche, restoring
Not a thing I own is stock.
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03-31-2019, 02:12 PM
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Join Date: Aug 2017
Location: Sebastopol,CA
Posts: 358
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Quote:
Originally Posted by Brantel
I wish you the best of luck in your endeavor. I find it strange that you are so eager to dismiss simple proven technology/concepts and so willing to bet the farm on a smoke filled black box (not literally, just an analogy) that you have no real knowledge of internally. Your mind appears to have been made up long ago and the true motive behind these post appears to be something different than stated.
As I said before, this has nothing to do with EarthX and their BMS, I would use them in a heartbeat. It is about how they break your criteria you specified earlier. Seems to be very double standardish in nature.
But hey, this is experimental aviation. Go for whatever you like and want to do!
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Brantel, Thanks for participating, I appreciate your input. It is a bit troubling to have my motives questioned, and I don?t understand at all what you mean in saying that I am dismissive of simple proven technology. What I?m trying to do is align the design of modifications to my airplane with current technology, and share this process with others facing similar challenges on this incredible forum.
High energy-density batteries and electron-dependent aircraft are both game-changers, and thinking outside the box of magneto-era solutions is very much called for. If you really spend some time with the schematic I presented, it should become clear that it does a very good job of meeting those goals where electron supply and management is concerned, and that it also scores very highly against any criteria for redundancy. -Otis
__________________
Otis Holt-
RV-7A (bought)
Built Monnett Moni
Frmr Test Pilot/Author CAFE APR's:
RV-8A, S-7C, Europa, Glastar.
-2019 VAF donation!!-
"RV-Fun is inversely proportional to RV-Weight!"
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03-31-2019, 02:42 PM
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Join Date: Jun 2010
Location: Sunman, IN
Posts: 2,189
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Yes
Yes, there are many here who choose the status quo because that?s how it?s always been done...
Had Van himself used that line of thinking, there would be no RVs to fly and this discussion would not be taking place...
__________________
Bob
Aerospace Engineer '88
RV-10
Structure - 90% Done
Cabin Top - Aaarrghhh...
EFII System 32 - Done
297 HP Barrett Hung
ShowPlanes Cowl with Skybolts Fitted - Beautiful
Wiring...
Dues+ Paid 2019,...Thanks DR+
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03-31-2019, 02:56 PM
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Join Date: Aug 2005
Location: Dallas/Ft Worth, TX
Posts: 5,686
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Quote:
Originally Posted by rocketman1988
Yes, there are many here who choose the status quo because that?s how it?s always been done...
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Or maybe some of us prefer not to be test pilots in this hobby, give me a million hour proven method of doing things and I'm ok with that.
When I was younger (and invincible) I might have tried to put a V8 in the RV if someone suggested it, but I like to think I'm a little wiser now.
__________________
Walt Aronow, DFW, TX (52F)
EXP Aircraft Services LLC
Specializing in RV Condition Inspections, Maintenance, Avionics Upgrades
Dynamic Prop Balancing, Pitot-Static Altmeter/Transponder Certification
FAA Certified Repair Station, AP/IA/FCC GROL, EAA Technical Counselor
Authorized Garmin G3X Dealer/Installer
RV7A built 2004, 1700+ hrs, New Titan IO-370, Bendix Mags
Website: ExpAircraft.com, Email: walt@expaircraft.com, Cell: 972-746-5154
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03-31-2019, 03:14 PM
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Join Date: Jun 2010
Location: Sunman, IN
Posts: 2,189
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And
...and everyone is entitled to their own opinions in our wonderful hobby...
It is unfortunate that there are some that can?t accept that there is more than one way (their way) to do things, and still end up with a safe, reliable machine.
That being said, changes and modifications are not necessarily for everyone...and I am ok with that.
__________________
Bob
Aerospace Engineer '88
RV-10
Structure - 90% Done
Cabin Top - Aaarrghhh...
EFII System 32 - Done
297 HP Barrett Hung
ShowPlanes Cowl with Skybolts Fitted - Beautiful
Wiring...
Dues+ Paid 2019,...Thanks DR+
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03-31-2019, 06:24 PM
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Join Date: Aug 2005
Location: Dallas/Ft Worth, TX
Posts: 5,686
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Quote:
Originally Posted by rocketman1988
...and everyone is entitled to their own opinions in our wonderful hobby...
It is unfortunate that there are some that can’t accept that there is more than one way (their way) to do things, and still end up with a safe, reliable machine.
That being said, changes and modifications are not necessarily for everyone...and I am ok with that.
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Very true, but …
I think the motivation for many posts, including my own, is to try to keep this hobby as safe as possible especially for those that may not have the insight/experience in this business to necessarily determine what's safe on their own.
__________________
Walt Aronow, DFW, TX (52F)
EXP Aircraft Services LLC
Specializing in RV Condition Inspections, Maintenance, Avionics Upgrades
Dynamic Prop Balancing, Pitot-Static Altmeter/Transponder Certification
FAA Certified Repair Station, AP/IA/FCC GROL, EAA Technical Counselor
Authorized Garmin G3X Dealer/Installer
RV7A built 2004, 1700+ hrs, New Titan IO-370, Bendix Mags
Website: ExpAircraft.com, Email: walt@expaircraft.com, Cell: 972-746-5154
Last edited by Walt : 03-31-2019 at 06:54 PM.
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04-01-2019, 08:28 AM
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Join Date: Aug 2007
Location: Ontario, Canada
Posts: 2,291
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Otis - a very simple comment here...
Your "momentary" switch concept is interesting in concept, however I would advise that in its real-world application it may be a little more difficult than expected to actuate that momentary switch.
Solely from an ergonomics standpoint I would suggest replacing that momentary toggle switch with a "start" push button momentary switch as is available from both Stein and B&C. The push button is far easier to actuate. Its form factor nestles in very neatly beneath the flip-up plastic switch guard. The push button is just a lot easier for our fingers to manipulate.
Switch example:
https://www.steinair.com/product/starter-switch/
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04-01-2019, 07:41 PM
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Join Date: Feb 2010
Location: Gardnerville Nv.
Posts: 2,828
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Trying to digest your main goal here, one of your statements about having 800 CCA for starting with two batteries, if you are using the Earth X 900, you will not need two of them, one of them will crank your prop fast enough to taxi with the starter alone  Also these new batteries keep their charge for a long time with very little discharge, these can sit for months with no trickle charger and start just fine, even in cold weather. I tried the schottki diode with heat sink for charging the backup battery but it did not do well, so I just tied in a manual switch to top off charge it during runup and taxi, then off. Ready to go for backup at the flip of a switch. Also, keeping the secondary battery isolated protects it if a runaway alternator goes crazy, or the crowbar fails and takes the main battery off line. With my set up if this happens, I just shut off the master, turn on the back up battery and everything comes alive......for about 90 min.
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7A Slider, EFII Angle 360, CS, SJ.
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04-02-2019, 08:48 AM
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Join Date: Apr 2008
Location: Riley TWP MI
Posts: 3,070
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There is a flaw in the schematic. The diodes prevent the small relays from energizing.
__________________
Joe Gores
RV-12 Flying
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04-02-2019, 10:53 AM
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Join Date: Jun 2016
Location: coupeville wa
Posts: 134
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Electrical systems reviews
Otis,
I wouldnt fault you for wanting to experiment and look for a better way. In a past life I spent a lot of time looking over the work of young engineers looking for a more inovative way to use new technology to solve avioncs and control systems problems. How to develop a culture of critical review without being disparaging or discouraging others to risk being dismissed as incompetent is critical to getting the best out of the process. Doing it at arms length over the internet in a hobby environment is even more difficult.
Many approaches to system design are flawed due to starting out with a concept and then trying to make it fit the situation - a solution looking for a problem if you will. The telltale signs are lack of balance in the design ( do we have a complex solution for a simple straightforward problem), patches to mitigate undesirable features or holes in the proposed design and finally the need for components with very tight tolerances or hand selected characteristics. Only you can make the determination of what is right for you for your electrical system - I would encourage you to do a critical review with those three concepts in mind before casting your design in stone. You may decide to proceed with what you have or you may decide to put it to one side and start over with a clean sheet of paper. I hope it is the latter.
KT
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