General questions regarding designign a panel ( instruments to include, wiring, etc.)

Discussion in 'General Experimental Aviation Questions' started by mcurcio1989, Jan 5, 2015.

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  1. Jan 5, 2015 #1

    mcurcio1989

    mcurcio1989

    mcurcio1989

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    The project is an Aventura II which is very similar to the sea rey. Time has come to lay out my panel. The engine I am using is a Suzuki automotive conversion similar to the Honda Viking in operating principles.

    I was trained in a Pietenpol with an A65 engine and the operation and MO on this aircraft is obviously quite different. The knowledge that I am bringing in is very limited in this area as a result.

    As of now my plan is to have an Altimeter, Air speed, VSI tach, water temp, oil pressure, Fuel gauge, voltage gauge and I'm debating on oil temp and egt / cht. I have the oil temp and egt / cht gauges but I'm just not too sure if I want to install them. Unless I buy 4 cht probes, 4 egt probes and the switches for them i think the egt / cht is largely worthless and that cost will add up quick and I 'm just not sure if it really adds any value. With a water cooled engine I see oil temp as not providing a whole lot of information.

    This engine is obd2 and I will have a bluetooth dongle which will be connected to a dedicated phone (operating as a small instument panel) giving me additional engine diagnostics such as 02 sensor output. I see that as providing as much indication as a single egt probe would.

    My other big question is the power circuits. What would you typically include on circuits and what should have dedicated circuits?

    I'm going to have a radio, intercom, and transponder. I've had a really hard time finding information on these things. Specifically reviews. I want to go used as much as possible on these. I've seena lot of the KT76a' transponders by king for a very reasonable price. Any experience with those?
     
  2. Jan 5, 2015 #2

    Joe Fisher

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    Re: General questions regarding designign a panel ( instruments to include, wiring, e

    Part 91 requires oil temp on air cooled engines OR water temp on liquid cooled engines. Other wise what else you use is up to you.
     
  3. Jan 5, 2015 #3

    mcurcio1989

    mcurcio1989

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    Re: General questions regarding designign a panel ( instruments to include, wiring, e

    . . I guess the question then is really what do you all see as worthwhile gauges for this kind of installation and usage? In addition to what I have listed, if any, that is. I don't have an excessive amount of space on my panel so I'm afraid that if I leave something off it will be hard to make room later if / when I decide I want to add something.
     
  4. Jan 5, 2015 #4

    Dana

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    Re: General questions regarding designign a panel ( instruments to include, wiring, e

    That only applies to standard category aircraft; there are no specific requirements for experimentals.

    Dana
     
  5. Jan 5, 2015 #5

    Jan Olieslagers

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    Re: General questions regarding designign a panel ( instruments to include, wiring, e

    Anything electronic should be behind a fuse AND protected with a crowbar circuit.
    To decide what to wire behind which fuse, think about redundancy: if transponder and comm's and GPS are on one and the same fuse, blowing that fuse will leave you rather naked. Just as an example.

    You definitely want a separate fuse for the charge current from the alternator to the battery.

    Answering a question you did not ask: consider a battery master switch, if only for the day your cockpit suddenly begins to fill with smoke.

    And instead of an analog voltmeter, consider a little led bar, kits are plenty and cheap, most use the LM3915 IC. Cheaper, more accurate and easier to read than an analog instrument.
     
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  6. Jan 6, 2015 #6

    mcurcio1989

    mcurcio1989

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    Re: General questions regarding designign a panel ( instruments to include, wiring, e

    ^Thank you for the info very good things to look at. DO you have any master switches you could recommend? This is all I found. I guess 20 amp may be enough.

    Master from Aircraft Spruce

    or something like this.

    http://www.amazon.com/Battery-Master-Isolator-Switch-12V-24V/dp/B00MQU9YJ0/ref=sr_1_3?s=automotive&ie=UTF8&qid=1420508417&sr=1-3&
    keywords=master+switch+boat


    I know it seems trivial but it makes me nervous since its a single point of failure.
     
  7. Jan 6, 2015 #7

    Jan Olieslagers

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    Re: General questions regarding designign a panel ( instruments to include, wiring, e

    A real "master" switch switches everything, including the starter, so 20 amp is definitely insufficient. It is indeed the second type I was thinking of. However some of those shown are so cheap that I would mistrust them in a plane.

    As for single points of failure, there are already so many that one more won't change much. The pilot, to begin with, next the engine, propeller, you name it.
     
  8. Jan 6, 2015 #8

    Magnus Wallner

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    Re: General questions regarding designign a panel ( instruments to include, wiring, e

    The first master from Spruce is either more of an avionics master or a trigger for a remote relay. It will not work solely as a battery master.

    The second on is a standard type battery switch. I've seen the cheap types fail (on boats) so get a good quality one and make sure you can reach it easily in flight.

    If you install an avionics master I suggest you get a secondary master (think: avionics bus 2) should the first one fail. But if you have a fairly basic panel, which it sounds like you plan to have, I'd rather not have a master but use the on/off-swithces on the radios.


    If you have an oil temp sensor and gauge, why not use it? I shut down an engine once due to loss of oil (leak). The oil temp was going up, less oil to handle the same amount of heat, but the pressure and cylinder head temp was ok. First I suspected a false indication but then the pressure started to fall (due to the hot oil).
    When water temperature indicates an overheat condition due to lack of oil it might already be too late.
     
  9. Jan 6, 2015 #9

    cluttonfred

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  10. Jan 6, 2015 #10

    mcurcio1989

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    Re: General questions regarding designign a panel ( instruments to include, wiring, e

    I like the idea of using dual master switches. I was actually thinking about that a few days ago. I would alternate their use when first starting up and then switch to both before take off to ensure I would know if one failed. As you all stated that is what concerned me about them. I too have seen them fail before. In my experience aftermarket automotive switches can be very subpar.

    I have the oil temp gauge but not a sending unit or a dedicated port for one at this time.

    ^I'll take a look at those article during lunch. Thank you very much for sharing! I think the idea of a standardized wiring coding system is great! I plan to draw up the entire diagram before hand and write up a brief description. I know on past projects after several month passing I will even forget how I ran something.

    This may be covered in those article but when it comes to wiring very little things can become big problems - One thing I have learned from my work experience of looking at custom panels is that labeling and zip ties are your friend are your friend! I always view a custom project like this as an opportunity to improve upon things that have bothered me when working on mass produced vehicles while taking advantage of methods that produce good reliability and ease of maintenance.
     
  11. Jan 9, 2015 #11

    mcurcio1989

    mcurcio1989

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    Re: General questions regarding designign a panel ( instruments to include, wiring, e

    Transponders - I have been advised by a trusted flying friend / mentor to purchase a tray for a transponder first, for the purpose of laying out my dash and then grab a deal on a used transponder to place in this tray when I see it come up an any of the online marketplaces. He is under the impression that the garmin GTX327 tray (link below) will work for both the garmin and a kingkt76a transponder (perhaps others as well). I have not been able to confirm this. Does anyone know if this is true? Also I have seen a lot of kt76a transponders for sale used but have not been able to locate kt76a installation kits sold on there own in a similar fashion as the gtx327 kit linked below. Many of the listings for kt76a's I have seen do not include the tray - If the two are compatible than this won't be an issue so I need to confirm this.

    Garmin GTX-320/327 Installation Kit
     
  12. Oct 8, 2019 at 2:54 PM #12

    Speedboat100

    Speedboat100

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    How do you make instrument panel vibration free ?
     
  13. Oct 8, 2019 at 3:40 PM #13

    Toobuilder

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    The wiring is easy. Buy Bob Nuckolls book and follow the instructions.

    As for engine instrumentation, there's not much reason to not have a full engine monitor these days. Buy a used EMS and be done with it. In fact, if you get lucky you can find a Dynon180 and have all flight and engine instruments in one lightweight box.

    Since you are "developing" a non standard engine here, full monitoring is even more important IMHO.
     
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  14. Oct 8, 2019 at 5:48 PM #14

    Dana

    Dana

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    CHT probably not too useful on a watercooled engine. EGT is nice when tuning. But... you mention OBD2, which I presume means keeping the original engine computer? They can get unhappy when expected inputs are missing, e.g. vehicle speed, the second O2 sensor that monitors catalyst efficiency, etc. And if you plan to run avgas, the O2 sensors definitely won't like the lead.
     
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  15. Oct 9, 2019 at 3:09 PM #15

    rv7charlie

    rv7charlie

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    Speedboat isn't the OP. Probably should have started a new thread for his question. Speedboat, with new, solid state instruments, vibration isn't much of an issue. Look at vibration isolators like Barry Mounts if you decide you really need them, but I haven't seen it done in a homebuilt in close to 30 years, even with conventional instruments.

    Charlie
     
  16. Oct 10, 2019 at 2:47 PM #16

    Speedboat100

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    Ok I did start a new topic for it...and found the same answer you just gave.
     

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