Glass panel vs. steam gauge instruments

monclerjacket · Post by **monclerjacket** » Wed Aug 21, 2024 8:48 am

GlenNJ · Post by **GlenNJ** » Wed Jan 29, 2014 7:24 pm

I guess another option would be steam gauges, and hand held devices.

Glen

Post by **psalter** » Tue Jan 28, 2014 9:18 pm

Glen,

Best way to think about a glass panel, is an aircraft radio or transponder. More than likely, they will be replaced over the life of the aircraft. Because of the development and testing time, avionics tend to stick around longer than commercial goods like smart phones. GRTs EIS (Engine Instrument Systems) has been around for at least 10 years. Several other avionics I can think of have been around about as long. I agree, if you expect it to last 40 to 50 years get a steam gauge. But, keep in mind, as steam gauges less common, they will be harder to get repaired.

Paul

GlenNJ · Post by **GlenNJ** » Tue Jan 28, 2014 8:43 pm

Tony & Paul,

You bring up some pretty good points. I guess my biggest fear about glass panels is the equipment becoming obsolete in the near future. As the next, "latest and greatest" model comes along, how long a manufacturer supports what they sell today, is anybody's guess. I do heating and air-conditioning work, and run into this problem all the time. Manufacturers will go out of business, or stop supporting older equipment. When you can't get the circuit boards for their machines, they usually become junk. Software updates can also cause problems. I'm sure most of us have flown 40 to 50 year old airplanes that still have their original steam gauges installed. These gauges might look dated, but they still work, can usually be repaired or easily be replaced if need be.

Glen

Post by **psalter** » Sun Jan 26, 2014 9:37 pm

Forgot to add, most of the displays are pretty good in sunlight. The LCDs that are available now are very bright. The units are pretty reliable, lifespans are measured in years. I have heard of many that are 5-10 years old with no problems.

Post by **psalter** » Sun Jan 26, 2014 9:34 pm

Glen,

Many of the glass cockpits have minimal filters, they will take care of small spikes, but not necessarily large ones. However, with the small loads on most aircraft now, especially homebuilts, there usually aren't many spikes. Mainly, only if there is a problem with the alternator, relatively rare.

You can add a "crowbar circuit" if you want that gets rid of large spikes and has a capacitor that also helps with low power fluctuations. These are fairly cheap, less than $100 and not to hard to wire in. We do not have this in the Panther, and have had no problems.

One of the big benefits of glass vs steam, especially in an aerobatic aircraft is the gyros. The electronic sensors in glass cockpits operate at any attitude without tumbling. Many mechanical versions will tumble at high pitch angles.

GRT has been in business many years, and will most likely be around for many more, but as with everything, there are no guarantees. Besides GRT, you can run Dynon, MGL, and Garmin just to name a few. Garmin of course is the biggest, but also the most expensive.

Sport Performance Aviation is a dealer now for GRT and MGL, but you are welcome to install any system you like. We want the builder to be happy with their aircraft.

One downside of glass, is they can be affected by EMI (electromagnetic Interference). Typically, this will manifest itself as engine instruments being erratic when you key the microphone. Using shielded wires as directed for the radio, a good antenna with a true connector, and good shielded antenna cables will get rid of this problem. Also, be sure to have good grounds. These are good practices for any electrical/radio system installation, not just glass cockpits.

And like you said, if you really want to, a couple of backup instruments could be installed, glass or steam.

Post by **Tony Spicer** » Sun Jan 26, 2014 7:31 pm

(a) General. Except as provided in paragraphs (c)(3) and (e) of this section, no person may operate a powered civil aircraft with a standard category U.S. airworthiness certificate in any operation described in paragraphs (b) through (f) of this section unless that aircraft contains the instruments and equipment specified in those paragraphs (or FAA-approved equivalents) for that type of operation, and those instruments and items of equipment are in operable condition.

Glen,

Experimental aircraft do not have a standard category airworthiness certificate.

Tony

GlenNJ · Post by **GlenNJ** » Sun Jan 26, 2014 7:01 pm

Tony,

I can't answer that question, because I have no interest in buying a GPS. If I lost my airspeed indicator in flight, I would just stick the nose where it should be, and fly by the "seat of my pants". Most of my flying will be local. My local airport is by the east coast. It's hard to get lost. If I do cross-countries, I'll break out the section charts and draw a line. The glass panel alarm system for engine instruments is a great feature. I can't agree with you on the blank panel/ day VFR EAB statement. Look up FAR 91.205(a) & (b). My FAR book is from 1998, but I think this rule is still the same.

Post by **Tony Spicer** » Sun Jan 26, 2014 4:12 pm

Glen,

Instruments in airplanes are highly overrated. It is perfectly legal to have a blank panel on a day VFR EAB. Part 91 does not apply. The only reason to go with steam gages would be if Uncle Ralph died and left you a box of freebies. Should you install them, just hope that you're looking at the fuel pressure when it slowly starts heading south. Or the oil pressure. Or the CHT heading up. Or the EGT going down. The value of glass is the ability to alarm every last thing that's being monitored. I know lots of folks flying with glass. I don't know even one that's lost one inflight. My RV-3 had the crap kicked out of it by a tornado. The Dynon fired right up the next day.

The time require to transition from steam to glass is at best 15 minutes.

The Panther prototype started out with MGL glass.

Question: Your glass craps out. You have a GPS. The windsock/smoke indicates a 10 mph headwind. You typically fly final at 60 mph. What GPS groundspeed should you fly?

Tony

GlenNJ · Post by **GlenNJ** » Sun Jan 26, 2014 2:11 pm

I was wondering if builders could share their views on traditional steam gauge instruments, vs. the new glass instrument panels. Team Panther seems to be pushing the GRT Avionics, Sport panel. It's a nice looking display, and seems like an affordable way to get all the information you need on one display. If you add up the prices for all the steam gauges, it seems to be cheaper to go with the GRT display. My concerns with glass cockpits are:
- If one part of the GRT display doesn't work (that's say the airspeed indicator), the airplane would be grounded until you send it somewhere to be fixed. With steam gauges, you can just swap out the defective component.
- Will GRT Avionics be able to repair their panel 5, 10, 15 years from now? Will they still be in business? If they go out of business, will anyone support their product?
- We all know how 5 year old computers, phones, pads, etc. are considered obsolete, and usually not worth fixing. Will this be the fate of glass cockpit displays?
- If the glass cockpit display is considered obsolete and must be replaced, will the old sensors work on the new display?
- What is the lifespan of a glass cockpit display, considering the harsh environment it's put in? (cockpits are hot in the summer, cold in the winter, humidity issues, possibly getting wet from rain when you open the canopy, etc.)
- How well can you see the glass panel display, when the sun is beating on it?
- Do glass cockpits have any built in protection to control voltage spikes?

I'm not trying to put down glass cockpits. I have never flown an airplane that had one. The closest experience I have had to a glass cockpit, was playing an F-18 computer game (buy the way, I hated the altitude and to a lesser extent the airspeed number bars). I can see some of the benefits of having a glass cockpit, like having all the information you need on one display. The total package would probably save some weight. There would be an initial cost savings, but again, I'm not so sure about long term costs. Might it be a good idea to have a hybrid panel (glass cockpit, with some steam gauge instruments like airspeed and altimeter) so the airplane isn't grounded if the display goes bad. If you look at Dan's old construction photos, it looks like he had a steam gauge panel initially, then switched to the glass cockpit later on.

Glen

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Glass panel vs. steam gauge instruments

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Glass panel vs. steam gauge instruments