Are steam gauge cockpits always lighter than glass?

Depends. A glass panel is generally lighter than an equivalent panel made of round gauges. Legacy panels need vacuum systems, regulators, filters, hoses, and stuff like that to drive the vacuum gyros. Those gyros are heavy in their own right.

Now, if you're replicating a J-3 panel, the round gauge panel might be lighter than the nearest thing in glass.
 
DMD3. said:
As there is a wide variety of panel options in the experimental world, is it a safe assumption that steam gauges will always weigh lighter than any kind of glass cockpit, even if it’s a relatively small screen with few other gauges?

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Your pic is of an RV-4. My RV-4 lost weight when I pulled out several steam gauges and vacuum system and replaced with a couple of small Dynon boxes and a Garmin portable GPS very similar to what you have pictured. It gained that weight back when I added more glass but that was along with things like magnetometers, a new prop, and a bunch of other stuff not related to the glass, even with the change to a lightweight starter and removing some weight in other areas. With no harmonic damper on the flywheel empty weight is very close to what it was with steam/vacuum. I like the CG shift with the damper more than I like the reduced weight without it.

Before:
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After:
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Nauga,
adding lightness
 
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My plane lost 10+ pounds going from vacuum to electric gyros. Taking out the vacuum pump and associated hardware makes a big difference. I also gained a ton of functionality.
 
Depends on what you're talking about exactly. A G5 weighs less than a pound. My old AI was 3.7. My old King 55 HSI system was something like 7 with the remote gyro. The last mechanical gyro I have is the TC and I'm thinking of getting rid of it to save another couple pounds. The vacuum pump, valves, filters, hoses, etc was another 5 or so.

A 10" g3x touch weighs 6.5lb, so it doesn't save quite as much, and people often put in two or even three, which is where the weight starts to add up.
 
Definitely, I lost ~50lbs, vacuum pump and electric backup, KNS80(5+lbs IIRC), electric turn coordinator was heavy too, VSI was light. So if replace old avionics as well as just 6 pack you can save some weight.
 
The G1000 system, which most pilots never see because it's hidden behind the panel and behind the baggage compartments, weighs more than steam. Easily. The displays alone are heavier than the steam gauges.

But it's old tech by now. New stuff will be a lot lighter.
 
I was just going to say the same as Dan above. I trained in steam gauge 172s until about halfway through training and then switched over to a G1000 172. That G1000 was definite heavier and you noticed it when it came time to land/flair.

I updated my original 1980 panel in a 172 with all garmin including 2 G-5 which allowed me to remove the vacuum system. It saved me some weight. It was in 2018 and I don't remember how much weight I saved. I gained it all back from drinking too much beer.
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I’ve mostly assumed glass vs. steam weights was a wash. Sometimes you gain a little weight and sometimes you lose a little weight after doing a project. The aircraft that I’ve weighed or had good weight and balance documents to start with have always come out fairly close to the same weight after I’ve finished the project and weighed them again.

In my experience, It takes a lot of effort and money to make big reductions in an aircraft’s empty weight.
 
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Digital instruments like Aerospace Logic are much lighter than OEM. My G3X Touch includes remote comm and txp so the GDU and breakers are the only thing in the panel. Compared to typical radios and analog gauges with equal capability as the G3X? I’d think the G3X probably has a slight advantage.
 
Stewartb said:
Digital instruments like Aerospace Logic are much lighter than OEM. My G3X Touch includes remote comm and txp so the GDU and breakers are the only thing in the panel. Compared to typical radios and analog gauges with equal capability as the G3X? I’d think the G3X probably has a slight advantage.
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Do you have the G3X EIS? I don't have time to add up the weights, but the following LRUs:
  • GDU 460
  • GSU 25
  • GEA 24
  • GAD 29
  • GMU 22
  • G5
Will replace at least the following:
  • Vacuum pump, filter, suction gauge, and plumbing
  • Vacuum AI
  • Vacuum DG
  • Electric TC
  • ASI
  • Altimeter
  • VSI
  • Two CDIs
  • Whiskey compass
  • Clock
  • Tachometer
  • MAP gauge
  • EGT/CHT gauges or engine monitor
  • Oil pressure gauge
  • Oil temperature gauge
  • Fuel gauges
  • Fuel pressure gauge
  • Fuel flow gauge
The remote boxes can also be moved around in the plane to solve small CG problems. And then there's the whole safety aspect of flying with glass. I don't know or much care if my plane would weigh a little less with steam instead of glass. The panel pays for its cost and weight every time I go on a trip and my engine gauges are right in my main instrument scan with all sorts of weather information far ahead of me available at a glance.
 
Yes on the EIS. No GAD or G5. I do have two AP servos, though. My components are on a shelf behind the panel. My boot cowl is removable for access but pulling the display works better for some things, like plumbing the GSU for the afterthought AOA probe addition.

I can’t imagine CG being a problem.
 
Van Bortel lists the G1000 suite at 45 pounds, not including servos, and that sure wouldn't include the sealed lead-acid backup battery either, which would be 10 or 12 pounds.

Do all the steam gauges, vacuum system and radio stack come to that? I doubt it. I've actually had the stuff out, as a mechanic.
 
Dan Thomas said:
Van Bortel lists the G1000 suite at 45 pounds, not including servos, and that sure wouldn't include the sealed lead-acid backup battery either, which would be 10 or 12 pounds.
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And on top of that, the Cessna 172/182 retained a vacuum system (dual pumps, I think) for the backup AI. Plus the KAP140 autopilot had a TC mounted blind.

The G1000 is ~20 years old. Moore's Law says there oughta be ~1024x improvement by now.
 
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