Trying to get my 182 lighter, already removed the standby vacuum pump and dme/adf, also did the firewall battery and wondering how much weight removing the vacuum system completely will save.

It has a wet vacuum pump now, I want to keep it ifr, so could put in another G5 to replace the DG. Wondering if it'd be enough weight off the nose to justify buying another gauge.

My 2cents- A wet vacuum pump driving a A/I is a pretty reliable primary source. If you're flying IFR for real, Its awfully nice to have an independent attitude platform for when the glass goes T/U. Notice I said "WHEN". Fly long enough with glass, and you will experience "rogue electrons" with their associated mayhem. The weight is just not all that significant in the big scheme of things. I guess you could go to an eletronic standby A/I., but then you need the standby battery etc. Just a lot of expense and more just chasing your tail. I get removing unneeded obsolete avionics to shed weight, but some of this weight shedding that some folks do is crazy. JMHO-Carry On.

Toss. There is no comparison between vacuum system reliability and “electrons”, rogue or not.

I ditched mine for dual G5's...

jaudette wrote:I ditched mine for dual G5's...

I am in the process of ditching the pump. Putting in 2 G5’s. After losing a pump at 10,000’ on top. Clouds solid from 9500 to the ground. Airliners icing up on the decent into Pittsburgh. Fortunately I still had 5 hours of fuel on board. Got to better weather. My backup is iPad with ForeFlight and synthetic vision.


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I have my panel out now doing twin flush mount G5's. I pulled the pump, filter, regulator, hoses, and a Garmin 106 and associated wiring. NET NET the total weight savings was 8lbs.

I now have an HSI that drives my A/P (with GPSS steering.) Pretty cool... And in the case of failure, you have two independent battery operated AIs. Pull the vac system.

Loosing less than 10 pounds to remove a second power source doesn't make any sense to me. I've had a complete power failure four times in my flying life...never a vacuum failure. Luck of the draw there, but still...

By the time you add a back-up battery you'll have spend a lot of money and saved zero weight. Besides...10 pounds in a 182 is negligible, even if you were saving it.

A second G5 is fine, but I would keep the vacuum, even if you add ten pounds doing it.

FWIW... the weight savings included the two batteries in the G5s. (the STC calls for use of the batteries in the units.) I just dont see the downside. To be in the blind, you'd have to loose all ships electrics, then loose one G5 battery, then loose the other. Pretty good redundancy.

You are also getting all the ancillary data like alt tape, VSI, airspeed, mag compass, etc... AND an HSI.

Two G5s run about $4600. In my case, after selling my unneeded Garmin 106 and Stec GPSS, the total cost was just about $3k. I've had two dry vac pumps go now in 2 different Skywagons, so it seemed like a no brainier to me.

And as far as the value of 10 lbs... It all adds up. LOL

I would toss it. I've had 1 vac failure and never had an electrical failure yet. I'm going with no vac on my 206 rebuild, but starting from scratch it won't cost a whole lot more one way or the other. I just feel better with the extra redundancy of glass.

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I guess opinions on the subject pretty much come down to each pilots history, which is purely anecdotal; mine included.

Shucking a viable power source for attitude flying doesn't make one bit of sense to me, unless you simply never utilize the attitude instruments to begin with and couldn't make use of them in a pinch. I'm not saying I'd recommend someone pay to install a vacuum system if they already had two electric instruments, or even pay to have the existing system rebuilt, but since it's there (and I assume it works), the weight-savings verses lost-utility doesn't make any sense to me.

I can damn near loose ten pounds by pissing prior to take-off and emptying my pockets of things I'm not likely to need on the flight, so I just don't see the gain. Pencil out what the cost per ounce is for the conversion from vacuum to two G5's and I'll bet that the weight of a paper chart is worth over a hundred bucks, never mind a bottle of water or spare quart of oil or the assorted clutter that's in every airplane seat pocket.

Hey...there's about 40 pounds of paint on that bird...why not strip all that off to save weight? (sarcasm)

People take this weight savings business too far sometimes. Ten pounds in a 182 just isn't worth thinking about, in my opinion.

A lot of peoples point of view is determined by whether or not they fly instruments much or are just using the airplane as a flying VFR 4x4. Squabbling about a few pounds in a IFR platform that needs reliability over inhospitable terrain of Alaska? Apples to Oranges. Comparing dry vacuum pump failures to a wet pump system? Again apples to oranges. While the G5's show some promise, they have been less than totally reliable so far. Too many comments of issues with them to depend on 100 percent in IMC. Maybe in the future when they have proven themselves.

Edit-I'd be curious to know the flying experience of the commenters on this thread? Might be reflective of their point of view?

At work I fly behind an Aspen Pro 1000and have flown lots (50+) hours in the last couple of years of actual and much more the previous 14 years and have never had an issue. I have had several alternator failures, but the backup battery has always come through.

I just installed two G5’s driven by a 750 in my Skywagon and expect the same reliability. I understand that is anecdotal as two different installs and manufacturers, however, I have turned the ships electrical power off to test the G5’s and they chugged right along. Over the last five years I have experienced at least two vacuum failures in my work aircraft, good thing our aircraft has dual pumps, so no real issue. I will gladly fly actual without a vacuum pump from hear on out as I believe the risk is very manageable. I would much rather fly hard IFR without a vacuum pump then launch at dark over inhospitable terrain.

My .02

Bigrenna wrote:I now have an HSI that drives my A/P (with GPSS steering.) Pretty cool... And in the case of failure, you have two independent battery operated AIs. Pull the vac system.

Out of curiosity, what autopilot did you install?

I pulled the entire vacuum system out of my C180 including horizon & DG.
Total weight loss was 14 pounds.
Installed a single G5 including backup battery, added one pound.

I'm a VFR pilot, I removed the vacuum stuff from my last 2 airplanes.
Thought about dong the same to the 180 but wanted to have something "just in case".
I did the G5 just before the STC'd version was introduced, I installed the "experimental only" version as a minor alteration.
I installed it, cost me $1400 & change for the parts plus my mechanic doing the paperwork.

I have had one glitch with the G5, just a week or two ago.
I was flying along and I noticed that it was indicating a left bank of maybe 10 degrees although the wings were level.
Turned it off, then turned it back on-- all was well. No problem since.
Might have been a bad deal if I'd been in the soup and not able to look outside & realize what it was doing.

The vac system is coming out of my 182 when I get to the panel part of my project. The certainty of eventual vacuum failure outweighs the risk of multiple digital units failing in my mind. They do communicate with each other but should operate independently if installed correctly, so it would take a pretty significant event to disable all of them at once. Now you ARE putting all AI eggs into a single electrical basket and must be mindful of that too. If the alternator fails you have a short time until the radios go dark, and the G5/etc backups should give you an extra hour of attitude control beyond that. A total charging loss in IMC is an emergency no matter what else is in the panel, so even the presence of vacuum does not grant "business as usual" flying.

For the occasional light IFR I'm likely to ever encounter (when I actually get IFR rated) it is well within my risk tolerance. Even if the electrical system is lost, the backup batteries should keep things running for quite a while until VMC can be found. I haven't tried to use a tablet AHRS arrangement yet, but that might serve as a tertiary source in a true emergency as well.

If I flew people for money or was expecting to fly hard IFR as a regular thing, my risk tolerance might keep the vacuum AI in the panel and just deal with the system requiring upkeep from time to time; then again I would probably be in a different plane if I needed to do those things. For what I expect this plane to do for me, electrical redundancy in the instruments is sufficient and the added maintenance and complexity of a vacuum system offers little to zero benefit.

FWIW I fully respect the decision of anyone who thinks they need a vacuum backup, even with multiple screens, batteries, etc. I agree the 10-15lbs of weight isn't a big deal if you want the isolated redundancy it brings.

In my limited weight saving efforts I will take what I can get since it does all add up. A few pounds here and there culminates into something meaningful if you keep at it, so that's a nice side effect of going glass - but not the main reason I want to do it.

Obsessing over weight savings is not something that I do, but 8-10 pounds is a decent chunk. In a 180/182, firewall battery, vacuum system removal and a minimalist interior will get you around 35-50 pounds of weight savings. That is a significant weight reduction for a small airplane.

As far as vacuum system reliability vs electric, either one can and may eventually fail. I would definitely rather have two G5s working for me over a vacuum system failure while in the soup.

Suppose you had an electrical system failure with 2 G5s installed. Then the G5 that provides primary attitude info poops out. Can the G5 that's set up as an HSI be easily reconfigured to provide attitude info?

In said unlikely emergency situation, I could use a tablet or phone for lateral navigation. Partial panel flying, using one G5 and Foreflight provides far better situational awareness than depending on the magnetic compass, turn coordinator and pitot-static gauges in my opinion.

I installed one G5 with an electric DG to get rid of my vacuum system. I'll probably install another G5 in the future.

Maybe I've been unlucky, but I have experienced oil leaks at my accessory drives and tachometer drives several times over the years. Therefore, a big factor for me was having these points plugged up tight on the accessory drive housing. Less possible points for oil to leak was a strong incentive to dump the vacuum pump and install electric attitude equipment and a digital tachometer.

Scolopax wrote: Suppose you had an electrical system failure with 2 G5s installed. Then the G5 that provides primary attitude info poops out. Can the G5 that's set up as an HSI be easily reconfigured to provide attitude info?

Yes the second G5 can, with a push of a button function as an attitude indicator. It also will display heading and track in the AI.

I would not want to use a G5 configured as a HSI as a backup ADI if the G5 configured as a HSI was the only nav indicator available to shoot an ILS or GPS approach with vertical guidance. Based on that my project 180 will have a vacuum powered ADI as a backup to a pair of G5's. As for 8 or 10 pounds, I am either not a good enough pilot for it to make a difference or a good enough pilot that it doesn't matter. For those of you that want the light empty weight, the question is, do you adjust your approach speed when landing weight changes by 10 pounds, 50 pounds, 100 pounds, or never adjust it at all and always use the same speed? If you do are you good enough to fly -0+1 of the correct approach speed for your weight? Do you operate out of strips where the difference of 50 or 100 feet on take off would make the operation unsafe? Do you operate with minimum required fuel or top it up when you refuel and take what you have? So I guess it comes do to how much of this weight chasing is for bragging rights around the camp fire or on the internet?

Sorry for the thread drift.

Tim

bat443 wrote:So I guess it comes do to how much of this weight chasing is for bragging rights around the camp fire or on the internet? Tim

There seem to be 2 groups of airplane owners in the 'backcountry' world: one counts ounces and the other will do anything possible to keep their plane far, far away from a set of scales. The mindset of "my plane is already 1800 lbs, whats another 10?" results in grossly heavy aircraft.

Everyone has a different mission. Similarly, no two pilots would complete an identical mission in an identical fashion.

If your number one priority with your particular aircraft is to get in/out of tight spots, then weight is king, period. On the other hand, the majority of guys that spend big $$ to save weight would be better off investing in practice fuel or eating Keto. In the end, to each his own; you've got to decide what makes sense to yourself, your budget and your mission.

I agree that weight is king but it is not just empty weight. It is attention to detail, adjusting your speeds as appropriate, carrying only the equipment and fuel you need. Just like automation will never replace an experienced airline crew no matter how hard airline owners and the FAA try to convince us, light empty weight and a highly modified airplane will not allow an inexperienced pilot to operate where a pilot landing at a short strip five or ten times a day can.

Tim