Interior weight differences

[231Pilot]

A lot of people have been showing pictures of their new leather interiors, and they are very beautiful.  Since useful load is an important issue to most Mooney owners (including me) I am curious as to the difference in total weight of a leather interior compared to a fabric interior. 

Let's face it, if the 30+ lbs. difference that a set of bladders can add to the weight of an aircraft can bring about heated exchanges on this board, any significant weight difference in interiors should be information that those who are considering interior refurbishments (possibly me) would want to know.

So if you install interiors, or if you have had one installed recently, what, if any difference is there between the two...not between your new leather interior and your old fabric one, but between new installations of each material?

Thanks for any and all feedback.

[jetdriven]

Our plane was not reweighed after the new paint or the new leather interior installed by the previous owner, so it must have not added anything 

I think that leather and fabric are similar in weight per SQ YD, IE 6-8 OZ leather will weight the same at 6-8 OZ fabric.   I think where the real weight gets added is soundproofing and the trend of covering the interior plastic with fabric or leather.  That adds weight and in a few years when it wears or the glue loosens up its not such a great idea anymore.  

I also think getting into a brawl over 30 LBS useful load is ridiculous seeing as how later M20Js got a 160 LB gross weight increase with nothing more than a rudder balance check, a revised airspeed indicator, and paperwork. A Bravo can weight 3368 LB.  Thats 628 LB more than a J with the same wing, tail, etc.   I'm not advocating flying over gross but I can say the wings won't fall off, either.

 

 

[panther1400]

I thought I heard about a gear change some where in the changes to the planes.

 

I agree about the adding weight, not because the plane can't handle it, but just to be legal and keep insurance company happy.  I am also looking at interior but looking at synthetic leather and might weigh as much as leather but have heard the 30lb number also as a rough guess.

[philipneeper]

i just redid my seats and they are about 5-8 lbs lighter than my orginals

[Shadrach]

I weighed all of the crap that  I pulled out verses what I put in and it turned out to be about a wash. The super sound proofing/ultra-leather that I used to replace the ceiling pieces was actually lighter than the foam rubber/cloth stuff that I removed.

[Txbyker]

Lew,

I just replaced my 20J interior and from what we calculated on paper it came to about 8 lbs increase.  That included ultraleather covering of panels, wool carpet, seats with the two front getting the special foam and headrest.  For my planning purposes I rounded up to 20lbs increase in my W&B app.

Russ

 

[1964-M20E]

If anyone is truly interested get with a mechanic who has a set of scales and do a complete weight and balance on you airplane.  You will then know the exact numbers for you plane when empty and you can go from there.  Somewhere I though I read that after painting the plane should be weighed and a new W&B done.  Not that I am that picky about it, but I think it would be a good idea after new interior and paint.

[Skyatty]

I just came through annual and decided to have my J reweighed.  The IA said, that like most people, most airplanes gain weight as they age.  We reweighed the aircraft largely because he found that five 337s had not been completed and he was concerned that W&B changes had not been updated correctly.  The aircraft was painted in the late 90s and has a relatively recent interior and much of the panel has been replaced.  The bottom line is that the aircraft was that I lost 110 lbs. of useful load based on the new weight - down from about 970 to 860.  Seemed like a huge amount to me and I may not have purchased the aircraft had I know the true empty weight.

[danb35]

There's never a requirement that we have our Mooneys weighed.  That said, it may be a good idea in some cases--there's really no way to calculate the effects of paint, for example, and even interior stuff can be hard to give a station to.  Also, over the years math errors in calculated W&B add up (and, in some cases, the math is wrong from the factory).

The downside is that you often find that your plane has gained weight compared to the records, and you've thereby reduced your legal useful load.  I'm tempted to buy a scale and weigh '48Q myself (yes, it can be done with one scale), but not sure I want to spend the $400 or so on that right now.

[231Pilot]

I am pretty certain that new interior of almost any variety is going to be lighter than the original stuff removed.  I am interested in knowing if a leather interior is heavier than a fabric one, and if so, how much heavier (or lighter).

The 30+ lbs. mentioned in the first post was a reference to bladders instead of sealing a tank and how heated the postings get on adding that small amount of weight. 

I am thinking about a refurbished interior on a 231, and there isn't much useful load to play with there.

[jetdriven]

Thats one reason not to weigh your airplane, I would guess that most airplanes on this forum would be 40-50 or more pounds overweight from what the paperwork says.  Why shoot yourself in the foot?  The orioginal weight was an estimate to begin with. If the prospective buyer raises cain about, let him reweigh it. Right now, its legal.

Commercial aircraft aere required to be reweighed every 36 months.  They also use estimated weights for passengers (includes carryons), and checked bags.  I had a fed ramp check me on the Beech 1900 once. We were flying out of Denver in the winter with lots of bags, coats, carryons, the works. He asked me if the aircraft may be over gross and I replied "I'm certain it is.". he asked what I was going to do about it, I replied "I'm flying this airplane to Wichita."  I reminded him that on paper it was legal and it was the FAA who approved the carry on baggage program and estimated weights.  Its legal.  Its legal.   We departed on time.

Quote: Skyatty

I just came through annual and decided to have my J reweighed.  The IA said, that like most people, most airplanes gain weight as they age.  We reweighed the aircraft largely because he found that five 337s had not been completed and he was concerned that W&B changes had not been updated correctly.  The aircraft was painted in the late 90s and has a relatively recent interior and much of the panel has been replaced.  The bottom line is that the aircraft was that I lost 110 lbs. of useful load based on the new weight - down from about 970 to 860.  Seemed like a huge amount to me and I may not have purchased the aircraft had I know the true empty weight.

[Skyatty]

With a 110 lbs. difference it becomes a safety issue.  There are good reasons for weight and balance restrictions, the foremost being safety.  Even if you decide to make a conscious decision to overload by a small amount, the unknown can kill you by increasing that unknown to unsafe levels.  I suppose shooting yourself in the foot on paper beats shooting yourself in the head in practice. Just my opinion.  I respect the envelope. 

Quote: jetdriven

[DXB]

Considering reweighing my C- feel like it should have more useful load than it does (894 calculated, even after completely redoing the panel with minimalist modern stuff).  But a prior owner replaced my old original interior with faux leather and fabric panels that have a metal sheet core, but no weight adjust at that time.  Is it typical to use these metal materials for interiors?  I thought most were plastic. Am worried that actual weight is worse, not better than calculated

[Raptor05121]

I'm scared to reweigh mine. In 2004 when she was fitted with a 3-blade, her useful dropped down to 1,003lbs. I removed a remote compass, radar altimeter, and several pounds of wiring. But even with removing some stuff, I'm sure I'll be down in the 900 range. I like my useful loads to include commas.

[Yetti]

I replaced my cloth side panels with leather over alum. The leather was heavier weight than "upholstery" weight leather. But it was on sale. The alum with leather was several pounds lighter than the factory cloth panels.

[DXB]

1 hour ago, Yetti said:

I replaced my cloth side panels with leather over alum. The leather was heavier weight than "upholstery" weight leather. But it was on sale. The alum with leather was several pounds lighter than the factory cloth panels.

Huh- thanks good to know

[M20F]

3 hours ago, Raptor05121 said:

I'm scared to reweigh mine. In 2004 when she was fitted with a 3-blade, her useful dropped down to 1,003lbs. I removed a remote compass, radar altimeter, and several pounds of wiring. But even with removing some stuff, I'm sure I'll be down in the 900 range. I like my useful loads to include commas.

I never understand this logic.

[Shadrach]

1 hour ago, M20F said:

I never understand this logic.

The logic is that the empty weight is already a soft (as in guesstimate) number from the factory. It's more likely than not that an aircraft was never weighed by the factory. The FAA does not really care what the airplane weighs, they care what the legal paper work says the airplane weighs. This is the incentive to ensure that the paperwork is correct and states the highest "soft number" legally possible.  Weighing the plane doesn't make it fly better, but it certainly might come in heavier, limiting its utility. If you reweighed your 67 Executive after taking possession form the factory, you'd have likely lost useful load right out of the gate. So the real question is does the plane become safer now that it's lost 10, 20, 30 or 40lbs of its "on paper" useful load? If you think the answer is yes, than I think you should have your plane weighed ASAP.  If you think that you know when to fly at gross (winter, cold and low) and when not to fly at gross (high and hot) and that a 40lbs paperwork change is not going to affect your personal margins, then it's probably more useful to spend your efforts elsewhere. Especially on an airframe that was certified to 2900lbs with 200HP.

Edited January 25, 2016 by Shadrach

[DXB]

4 minutes ago, Shadrach said:

The logic is that the empty weight is already a soft (as in guesstimate) number from the factory. It's more likely than not that an aircraft was never weighed by the factory. The FAA does not really care what the airplane weighs, they care what the legal paper work says the airplane weighs. This is the incentive to ensure that the paperwork is correct and states the highest "soft number" legally possible.  Weighing the plane doesn't make it fly better, but it certainly might come in heavier, limiting its utility. If you reweighed your executive after taking possession form the factory, you'd have likely lost useful load right out of the gate. So the real question is does the plane become safer now that it's lost 10, 20, 30 or 40lbs of its "on paper" useful load? If you think the answer is yes, than I think you should have your plane weighed ASAP. If you think that you know when to fly at gross (winter, cold and low) and when not to (high and hot) and a 40lbs paper work change is not going to affect your personal margins, than probably more useful to spend your effort elsewhere. Especially on an airframe that was certified to 2900lbs with 200HP.

Ross, I  agree, but unless I'm mistaken, my '68C did appear to have been weighed at the factory.  Useful load per the TCDS is 1050, but my original factory W&B sheet says 1005 after weighing- I don't see any calculation subtracting optional factory equipment from 1050 on the sheet.   I'm not a 100% sure on this- I'll have to recheck tonight, and someone with direct knowledge of the production process may be able to shed more light.

Regardless, I do feel a strong urge to know what my plane actually weighs. The calculated one for a 50 year old plane might be wildly inaccurate in either direction. I assume staying under the official max gross provides a wide margin of safety around most situations in which I would be likely to use it.  If I want to get the max utility out of the plane by loading it up, trying to simply guess exactly how wide that margin is at any particular DA seems too risky without deep aeronautical engineering and test piloting knowledge. Byron's situation where useful load increased for later years of the identical airframe and powerplant seems like a special case where there's clear quantitative indication that the margins built into his year were much wider than necessary.  

As far as the weight on the official document, that is a somewhat distinct issue. I suspect that I have more useful load than calculated, but don't want to give up official useful load on it if I'm wrong - as it may impact the value of the plane.  There is also urge to have the legal option to occasionally use a small amount of load that is not really there based on the actual weight, knowing the wide built in margins, but this is probably not the healthiest mindset.  

Is it unsavory to ask an A&P to "unofficially" weigh the plane, then write up officially only if the result is in my favor?

[carusoam]

Weigh it so you know.  

The PPI is going to let the next buyer know.

Expect that Back in the day the factory weighed a sample of the planes coming off the line.  Probably didn't weigh every plane.

MGTW and density altitude are important to your long term health as is max power at T/O.

If you can measure it, do so.  If you can't, get your best estimate and apply a proper margin of safety...

If you measure all of these, the proper margin of safety is still quite large...

Engineer, not CFI ideas...

Best regards,

-a-

[M20F]

2 hours ago, Shadrach said:

The logic is that the empty weight is already a soft (as in guesstimate) number from the factory. It's more likely than not that an aircraft was never weighed by the factory. The FAA does not really care what the airplane weighs, they care what the legal paper work says the airplane weighs. This is the incentive to ensure that the paperwork is correct and states the highest "soft number" legally possible.  Weighing the plane doesn't make it fly better, but it certainly might come in heavier, limiting its utility. If you reweighed your 67 Executive after taking possession form the factory, you'd have likely lost useful load right out of the gate. So the real question is does the plane become safer now that it's lost 10, 20, 30 or 40lbs of its "on paper" useful load? If you think the answer is yes, than I think you should have your plane weighed ASAP.  If you think that you know when to fly at gross (winter, cold and low) and when not to fly at gross (high and hot) and that a 40lbs paperwork change is not going to affect your personal margins, then it's probably more useful to spend your efforts elsewhere. Especially on an airframe that was certified to 2900lbs with 200HP.

I have posted a couple of times after I purchased my F I had it reweighed.  I guess I fall into the category of it is either right and correct or it isn't.  

[Raptor05121]

4 hours ago, M20F said:

I never understand this logic.

What logic?

[Yetti]

Walking out at the end of the annual I saw some scales and asked the IA if they work.  He said sure you can borrow them at anytime.   It's tempting

[ArtVandelay]

You would have to drain the fuel tanks completely, kinda of a PITA.

[DXB]

Could one get an estimate by weighing with the tanks topped off and then subtracting that weight?  This might at least give a sense of whether worth it to reweigh formally.