How do planes gain weight?

Morgan3820

Morgan3820

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I am trying to lower the empty weight in my Warrior. Aside from going on a diet, how do planes gain weight? :dunno:My plane is 70 pounds over factory empty weight. I know that factory weights are unrealistic and that 70 pounds might not be too bad but I am looking for improvement. I have the standard panel with 2 navcoms, DME, transponder, audio panel. There was an ADF I had removed.
 
Avionics upgrades are one way because the installer seldom removes old wiring. It is simply abandoned in place and new wiring installed.
 
The easiest weight to lose is with a good cleaning. You'll be amazed how much oil soaked dirt and grime you're likely to find on various nooks and crannies.

The next easiest is to go to lighter rotating electrics. As an example, see attached photo of the gear on my travel air. On your warrior you mighe be starting with a chrysler alternator instead of the monster deocl generator I had so there might not be much to gain there, But if you have the original huge starter that is a great place to begin.

After that I'd start looking for unused wiring, brackets, hardware, etc that were left behind when equipment was removed. Most shops are lazy and don't remove everything when they tear out an old autopilot, intercom, whatever (or the owners are cheap and don't want to pay the shop to do it).
 

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Several ways a plane can gain weight. But first, are you saying YOUR plane is 70 pounds over the weight it was when it came from the factory? Or are you saying it is 70 pounds over what the average empty weight in the manual says it is?

In the latter, those weights are more or less average. Well, more on the optimistic side of average, I would say.

In the former, there are many reasons why planes gain weight. Orphaned wiring from long removed equipment. Oil and grime in the belly that accumulates over the years. Undocumented additions. Etcetera.

I don't know if it applies to your plane, but in the distant past, they didn't actually weigh every plane that came out of the factory. They would weigh every 5th one, or so, and sort of use that as an average for the others. Not saying there was a significant difference, but every little bit adds up over the years.
 
I am in the upholstery/fabric supply business. If you go from cloth to vinyl, you'll double the weight of the upholstery easily. Leather is even heavier.

So, if your plane started with a cloth interior, using, say 15 yards of cloth, that's about 15 pounds of cloth. Let's say you reupholster the seats with straight vinyl, you're now at 30 pounds. Add leather into the mix, and you may be around 40 pounds of material. You've just increased your weight by 15-25 pounds.

That's one of the biggest reasons why the later model Saratogas are much heavier than the earlier ones, and even the Lances. I would imagine the Cessnas are similar.
 
First: Define "factory empty weight".
 
They overeat and stop doing exercise.
 
frfly172 said:
They overeat and stop doing exercise.
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That's how I gained 50lbs in two years. My first son was born and I went from running 70~80 miles per week to not running much at all, while still eating the same. 3 years later and I'm trying to get back into it. Ugh.
 
Take a look behind the back bulkhead. If any avionics were replaced, the odds that the old equipment is still there. Disconnected, but still there. Old avionics often had the guts behind the baggage area and only the indicator up front in the panel. Which means lots of wiring, too.

While the cherokee was down for the overhaul, I had the shop pull the old wiring. Gained 10 pounds, which was eaten up by the new insulation in the walls and overhead.
 
It might be my tools that I left in the tail. Could you send them back when you find them?
 
kmead said:
It might be my tools that I left in the tail. Could you send them back when you find them?
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:rofl:

Others have stated where the gains come from. The 310 has lost 100ish lbs under my care. Avionics, starter/alternator, and removal of other junk all adds up.

Weight loss is great, it's improved performance in all phases and it's a useful load improvement.
 
Doublers, Adel clamps, vernier throttle/mixture controls, you name it -- each one is under 1 lb when you add it, so it's "negligible" and there's no W&B change for any individual addition, but a pound here and a pound there, and after 40 years or so, you're talking about a lot of weight.
 
Someone mentioned paint. That is especially true if it was a scratch and shoot job instead of being stripped before shooting.
 
Morgan3820 said:
I am trying to lower the empty weight in my Warrior. Aside from going on a diet, how do planes gain weight? :dunno:My plane is 70 pounds over factory empty weight. I know that factory weights are unrealistic and that 70 pounds might not be too bad but I am looking for improvement. I have the standard panel with 2 navcoms, DME, transponder, audio panel. There was an ADF I had removed.
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Scum and scunge. Oil and dust nd detritus, tools left in fuel tanks (no kidding, when I replaced my Left main bladder, I found a 2' long Craftsman screwdriver in it.), then there is also the fiberglass insulation , it's hygroscopic and will gain water weight in time as well as molds and funguses, especially if there are any leaks. Carpet collect sand and grit,...

If you ever completely take the interior out and clean everything up (including left ove unused wiring from avionics upgrades, what came out of the 310:yikes::yikes::yikes: boxes full of boxes and big unused looms of wires. Between the panel and avionics clean up and the conversion to alternators I lost 200 lbs.) and take a steam cleaner to the airframe like you're doing a restoration, then put in all new, fresh, clean materials, you get back down to weight. A few pounds here and there adds up fast.
 
I don't know how Piper did things but Cessnas left the factory with calculated weights, not actual. The two I've owned were about 100# heavier than the factory weight including optional equipment. It's common. Some guys resist getting a new W&B. I like real numbers. I've weighed my current plane 3 times after various mods. I like current weights and accurate equipment lists. A few years back I rebuilt a PA-12 from the ground up. New engine, engine mount, airframe, gear.... that's a fun W&B. I could've sold squares for a pool bet.
 
Ron Levy said:
Or if you replace a thin enamel coating with a nice thick polyurethane job, even if you strip first.
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Actually Poly is lighter 3 mils is the standard. Cessnas came from the factory with a 5 coat lacquer finish.

The difference between a painted and a polished 172 was 15 pounds. sea plane corrosion proofing 22
 
ahkahn said:
I am in the upholstery/fabric supply business. If you go from cloth to vinyl, you'll double the weight of the upholstery easily. Leather is even heavier.
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I don't know what leather you are using but this interior was much lighter than the old fabric that came out.

You make up a lot of weight with modern padding.

old interior was nugies & excelsior , new wool and leather comfort foam interior by Stitch.
 

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Tom-D said:
I don't know what leather you are using but this interior was much lighter than the old fabric that came out.

You make up a lot of weight with modern padding.

old interior was nugies & excelsior , new wool and leather comfort foam interior by Stitch.
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Layman's terms here:
Foam padding is "material" and air bubbles (similar to bread). That ratio is referred to as density (NOTHING to do with firmness), and is measured by the weight of the foam padding. The higher the density/weight of the foam padding, the more wear and tear the foam padding can handle, and the higher the price of the foam. If your foam padding was replaced with a lighter foam padding, it will not hold up as long as the original... and is an easy cost-savings method for an upholsterer to employ. Foam padding has not changed since it was invented... other than people are using lighter and lighter densities over the years for cost savings. Think of a couch purchased in 1972 vs. one purchased today. Much lighter and cheaper, but throw it away after 3 years.

I was referring to only the fabric/vinyl/leather cover, not the foam padding. Most of the time foam can be reused... but if it was changed out, see my explanation above. That is not an area to cut quality corners on.

FWIW, I do not do upholstery work... I sell the materials to the people who do.
 
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I suspect a lot of the clean up probably makes the plane lighter, but it probably doesn't do anything for the book numbers. A lot of that added weight was never reflected in the aircraft weight figures.

When I substantially renovated my plane and reweighed it, the resulting weight was pretty close to the 50 years of calculated W&B changes. This was after removing old wiring, insulation, and probably 20 pounds of 5606 that had soaked into the carpeting.
 
kmead said:
It might be my tools that I left in the tail. Could you send them back when you find them?
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Are you missing a flashlight?

7feb6d1049a0d012b7d0496a9e588662.jpg



Sent from my iPhone using Tapatalk
 
Miss Piggy didn't get her name for nothing. Like her owner, she has been gaining weight since birth, which was one year before my own.

Areas of weight gain:

o Paint, she was originally bare aluminum
o Engine, not only weight gain itself, but along with a modernized O200A came:
Oil Filter
Different mags
Heavier air filter box
o Custom Panel with lots of heavy early eighties avionics
o 150 components including:
o Wheel pants
o Seats
o Wheels and brakes
o Custom landing light in nose
o A coating of some sort applied inside the fuselage
o Zinc chromate in the wing structure
o Strobes
o ELT


I fully expect that there are many other things that I did not think of or even know about. a few pounds here and there add up quickly, since the aircraft is very light to start with. It only takes ten or fifteen pounds on many small planes to give a 1% increase. It doesn't sound like much, but it is.
 
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I need to worry about my fat azz before I worry about the airplanes waistline. :eek:

#Iweigh295 #Imalardazz #workingonacoronary
 
OkieFlyer said:
I need to worry about my fat azz before I worry about the airplanes waistline. :eek:

#Iweigh295 #Imalardazz #workingonacoronary
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LOL! :goofy:

Im in the same boat, I could lose some weight cheaper than the airplane can! :rofl:


Maybe not faster though? :mad::dunno:
 
If it's an old enough airplane, there is probably five pounds of dirt, grease, and bug carcasses tucked throughout the airframe.
 
Stewartb said:
Is that just the zinc chromate or the seaplane kit which included fuselage doublers, etc?
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That number would probably be whole thing, but the corrosion proofing was available for the 100 series at $45.
 
Morgan3820 said:
I am trying to lower the empty weight in my Warrior. Aside from going on a diet, how do planes gain weight? :dunno:My plane is 70 pounds over factory empty weight. I know that factory weights are unrealistic and that 70 pounds might not be too bad but I am looking for improvement. I have the standard panel with 2 navcoms, DME, transponder, audio panel. There was an ADF I had removed.
Click to expand...

Dirt.
 
kmead said:
It might be my tools that I left in the tail. Could you send them back when you find them?
Click to expand...

I thought it was all the panties ripped off in a fit of passion. :) Everyone knows being a pilot is a aphrodisiac.
 
Norman said:
Avionics upgrades are one way because the installer seldom removes old wiring. It is simply abandoned in place and new wiring installed.
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Troof. My avionics shop removed several pounds of old wiring and even an old converter box of some kind (she told me but I don't recall) - none of which was in use even in the old configuration.
 
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