Opinion on removing vacuum system after two G5 installation

[redbaron1982]

Hey, I was going to ask about the useful load gain by removing the vaccuum system, I've read two persons here mentioning 50lb by removing all the vaccuum system include the main and backup pump. I assume this factors in also the weight gain/loss of replacing the mechanical AI and HSI by the G5s.

That's the number that we should expect by doing this upgrade/replacement? That makes going to G5s (or Gi275) even more intereseting.

Regarding redundancing, I think having two G5s that can be one backup of the other, plus a Stratus+ForeFlight, is much more redundant than the original vaccuum with a single AI.

[hammdo]

I'd be careful of what to expect. I had mine re-weighed after all the upgrades and removals and lost 30 lbs of UL.  50+ years of 'no increase in weight' of minor upgrades catches up...

-Don

[rbp]

17 minutes ago, hammdo said:

I'd be careful of what to expect. I had mine re-weighed after all the upgrades and removals and lost 30 lbs of UL.  50+ years of 'no increase in weight' of minor upgrades catches up...

-Don

i don't understand this thinking. you didn't lose any UL. with the old weighing, when you flew at calculated MGTOW, you were actually 30# over

[hammdo]

11 minutes ago, rbp said:

i don't understand this thinking. you didn't lose any UL. with the old weighing, when you flew at calculated MGTOW, you were actually 30# over

Assuming I flew max - which I don't. Essential it was probably 45 lbs heavier vs the calculated weights before the re-weight after all the upgrades. On paper, I lost UL.

-Don

[rbp]

9 minutes ago, hammdo said:

Assuming I flew max - which I don't. Essential it was probably 45 lbs heavier vs the calculated weights before the re-weight after all the upgrades. On paper, I lost UL.

-Don

From the POH

[Andy95W]

31 minutes ago, rbp said:

i don't understand this thinking. you didn't lose any UL. with the old weighing, when you flew at calculated MGTOW, you were actually 30# over

I do understand his thinking.

Instead of quibbling about 1% of the MGTOW, I’d much rather have the extra 5 gallons of gas.

[markgrue]

I guess I am on the other side of the fence about the ADF.  I added one about a year ago just for the thousands of navaids (am radio stations) in the US.   I have dual VOR and GPS but it is nice to have a needle that points to a known point.  I  did however install dual AV-30s to replace the AI and DG.  Vacuum system is gone.  I did weigh the airplane as I also installed an alternator and lightweight starter.  I also removed a bunch of unused wiring and avionics trays from some lost modification.  Total I lost 31lbs.  Last  actual reweigh was 93 when it was painted.  Calculation is seldom perfect. 

 

Mark Grueninger 

[rbp]

13 minutes ago, Andy95W said:

I do understand his thinking.

Instead of quibbling about 1% of the MGTOW, I’d much rather have the extra 5 gallons of gas.

I understand that, but let's not call it "Useful Load." that's MGTW - BEW. 

just call it what it is and say "oh, i don't mind flying 30# over gross."

[Guest]

Along with flying with an inaccurate weight and balance report, I never set the Baro scale on my altimeter and fly the ILS a few dots low.  So far it’s working out.

Clarence