One piece belly

[brad]

My IA asked if I have thought about the one piece belly mod for my 75 F.  Hadn’t really.  Is it worth the money?

 

 

[EricJ]

"Worth it" is totally up to you and your tradeoff assessments.   I don't have one and it's kind of nice to only have to take off the panel required to get at whatever it is you need, rather than having to take the entire thing off.

They're often installed as an easier way to repair the belly after a gear-up landing, which they're definitely good for, but beyond that I find it questionable.    There's a variety of opinion here, though, so it really comes down to your own tradeoff values.

[A64Pilot]

You have to define what value is.

As far as I know it only makes removal easier for inspection, something that I’m sure used to be a bear, but with battery powered drills I don’t find to be nearly as big a deal now. Maybe a J model is easier, less panels?

I would go out on a guess and guess some at least were added after a gear up, but that’s a guess.

Just me personally I’m putting the money into fuel.

[KSMooniac]

Many were added as part of a gear-up repair as it might've ultimately been faster and perhaps cheaper, but I'm not sure how many new "kits" might be available, either from the factory or the aftermarket.  I scavenged a used kit over the years and will install it one of these months as an elective upgrade... and I'd like to hide an antenna or two under it in my further quest for drag reduction.  Bill Wheat was working with Dugosh maybe 15 years ago and STC'd a carbon fiber version to keep the weight down, but I don't know if it is still available or not.  Antennas could not live under it, though.

[Fly Boomer]

On 7/10/2023 at 5:37 PM, KSMooniac said:

Many were added as part of a gear-up repair as it might've ultimately been faster and perhaps cheaper, but I'm not sure how many new "kits" might be available, either from the factory or the aftermarket.  I scavenged a used kit over the years and will install it one of these months as an elective upgrade... and I'd like to hide an antenna or two under it in my further quest for drag reduction.  Bill Wheat was working with Dugosh maybe 15 years ago and STC'd a carbon fiber version to keep the weight down, but I don't know if it is still available or not.  Antennas could not live under it, though.

I'm sure carbon fiber is lighter, but I was surprised how little the fiberglass weighs.  It's really thin.

[KSMooniac]

25 minutes ago, Fly Boomer said:

I'm sure carbon fiber is lighter, but I was surprised how little the fiberglass weighs.  It's really thin.

The factory belly is thin. but some of the aftermarket STC options that used to exist were quite fat and heavy.

[kortopates]

The factory went exclusively to one piece belly at some point around 86 since all the 252 K's have them and all long bodies. No screws eithers, just camlocs which go on and off quickly. I know I really appreciate the ease of mine at annual time so I am not surprised your IA asked you about it.

[glbtrottr]

Whats the pricing like these days for the various one piece belly’s?


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[1980Mooney]

In addition to ease of access to the belly (I think it is only about 14 quarter turn cam-locks on a J Mooney factory one piece belly) there is a small (claimed) speed increase.  The Mooney factory one piece belly is very light and easy to remove.  And antenna are mounted on the belly panel.

As @M20Doc says the kit is $5,000 but you need to add labor.  At Lasar they sell one piece bellies.  They say 35 hours to install on a short body and 70 hours on a mid and long body.

Mooney Speed Modifications - Lake Aero Styling & Repair — LASAR

[M20F-1968]

Mine was for Lasar and I think I paid about $3000 ten or more years ago.  The real "cost" is in the labor to install it.  It is definitely worth having.  It likely adds some speed as the belly is cleaner.  I is much easier come annual time.  The installation is not trivial and is more time-consuming than you might expect.

John Breda

[A64Pilot]

On 7/11/2023 at 7:11 PM, Fly Boomer said:

I'm sure carbon fiber is lighter, but I was surprised how little the fiberglass weighs.  It's really thin.

Glass isn’t really heavy, it’s the resin that adds weight. A “proper” hand laid glass layup and the resin squeeged out isn’t all that heavy. 

Yes carbon fiber is lighter but most of it is marketing, like Titanium is lighter than steel, but if aluminum can do the job Ti isn’t really much if any lighter, but it sure does market well.

Glass gets heavy if mat is used and in particular if a chopper gun is used, but nothing wrong with glass and unlike carbon there isn’t an issue with corrosion.

[FlyingDude]

For those of us that are CB, is there a mod to replace the screws on the existing multi-piece belly with camlocks or dzuses? I think this is actually a minor alteration (no change in flight characteristics, w&b)... 

The goal is to suffer once but save time later on during future annuals.  If I save fuel, I'll be a happy man. Not really counting on speed gains.

 

[ArtVandelay]

For those of us that are CB, is there a mod to replace the screws on the existing multi-piece belly with camlocks or dzuses? I think this is actually a minor alteration (no change in flight characteristics, w&... 
The goal is to suffer once but save time later on during future annuals.  If I save fuel, I'll be a happy man. Not really counting on speed gains.
 

Yes, I have camlocs on my 1 piece belly, about 20 of them.

[Vance Harral]

1 hour ago, FlyingDude said:

For those of us that are CB, is there a mod to replace the screws on the existing multi-piece belly with camlocks or dzuses?

Not that I know of.  But the best CB approach to maintaining the existing panels is a bin full of replacement screws (a lifetime supply is cheap); a lightweight, clutched drill driver with a good Phillips bit; a cotter key hook tool to align the Tinnerman nuts; and a paint job you don't care much about.

When it's time to remove the panels, use the driver to spin the screws out, and throw them away.  To reassemble, pull new screws out of the bin, install a couple to hold the panel in place and then use the alignment tool to verify all the Tinnermans are in place, then go to town with the driver.  Yes, you'll wind up with occasional scratches in the paint this way, even if you're careful.  For many of us, that's entirely worth the time and frustration saved.

[FlyingDude]

36 minutes ago, ArtVandelay said:

Yes, I have camlocs on my 1 piece belly, about 20 of them.

Could you send pictures? I'm not really into the one pieceness of the belly but the camlocks are worth the one time effort I believe.

@Vance Harral that's what I do now. 

[ArtVandelay]

Could you send pictures? I'm not really into the one pieceness of the belly but the camlocks are worth the one time effort I believe.
[mention=12653]Vance Harral[/mention] that's what I do now. 

Pictures of what exactly?

[KSMooniac]

By the time you install a couple hundred camloc fasteners (both sides!) in a metal belly, you could maybehave paid for a smooth belly conversion, or a big chunk of it.  You'll have to rivet the camloc receptacle into the structure of the belly, and then install the grommets, bodies, and retention rings in all of the panels.  Camlocs are not cheap, and installation is not trivial, and the weigh a lot more than a screw and a nutplate or tinnerman nut.  

[47U]

2 hours ago, FlyingDude said:

…is there a mod to replace the screws on the existing multi-piece belly with camlocks or dzuses?

I think Mooney used too many fasteners on the belly 3-panels-in-sequence installation from the nose gear rearward.  That’s A LOT of nut plates to convert to receptacles.    It might be less expensive labor/materials-wise to cut a sheet of aluminum and replace the 3 panels (or the back 2 panels?) as a single sheet.  The spacing of the fasteners on the left and right sides might need to be kept the same, but certainly the number of fasteners in the field of the panel could be reduced by maybe… half or two-thirds?

I took the time to put a dap of anti-seize on all the screws, wing panels included.  And I install them with a ratchet screwdriver.  I now rarely have stuck screw.  

[FlyingDude]

13 minutes ago, ArtVandelay said:

Pictures of what exactly?

The belly where it matches the side walls...

[EricJ]

1 hour ago, Vance Harral said:

Not that I know of.  But the best CB approach to maintaining the existing panels is a bin full of replacement screws (a lifetime supply is cheap); a lightweight, clutched drill driver with a good Phillips bit; a cotter key hook tool to align the Tinnerman nuts; and a paint job you don't care much about.

When it's time to remove the panels, use the driver to spin the screws out, and throw them away.  To reassemble, pull new screws out of the bin, install a couple to hold the panel in place and then use the alignment tool to verify all the Tinnermans are in place, then go to town with the driver.  Yes, you'll wind up with occasional scratches in the paint this way, even if you're careful.  For many of us, that's entirely worth the time and frustration saved.

^^This.    Once you get a methodology and a little discipline to keep the screws in decent shape it's not that awful to deal with.    I find that when removing them starting a quarter turn or so to break torque with a screwdriver, then coming back with an electric tool gets them all out reasonably quickly without damaging the screw heads.    A clutched screwdriver makes replacing all of them reasonably quick.

[FlyingDude]

14 minutes ago, EricJ said:

^^This.    Once you get a methodology and a little discipline to keep the screws in decent shape it's not that awful to deal with.    I find that when removing them starting a quarter turn or so to break torque with a screwdriver, then coming back with an electric tool gets them all out reasonably quickly without damaging the screw heads.    A clutched screwdriver makes replacing all of them reasonably quick.

Yea but that's what I've been doing! I don't get stuck or seized screws and all speed nuts are in shape. 

There are remote oil filter kits for C models, which people install due to the sheer amount of screws. I don't think those guys suffer from bad screws.

Anyway. I understand that nobody has done this alteration and those who have camlocks, got it that way with the one-piece belly...

Thanks anyway.

[1964-M20E]

20 hours ago, 47U said:

I think Mooney used too many fasteners on the belly 3-panels-in-sequence installation from the nose gear rearward.  That’s A LOT of nut plates to convert to receptacles.    It might be less expensive labor/materials-wise to cut a sheet of aluminum and replace the 3 panels (or the back 2 panels?) as a single sheet.  The spacing of the fasteners on the left and right sides might need to be kept the same, but certainly the number of fasteners in the field of the panel could be reduced by maybe… half or two-thirds?

I took the time to put a dap of anti-seize on all the screws, wing panels included.  And I install them with a ratchet screwdriver.  I now rarely have stuck screw.  

I have been threatening to make a single piece like this for years.

[FlyingDude]

Guys, frankly, I don't give a rodent's rear about the oneness of the piece.  3 is not too many.  Actually, smaller is easier to clean than a huge one.  Sheets #2 and #3 from front could be joined, at most, reducing the number to 2.  I wouldn't want a humongous sheet lying on top of me while I'm under the plane trying to stick the front of the sheet between the stringers and aft of the nose gear door, and screwing in the first pilot screws to hold it in place.  However, the multitude of the fasteners is shocking. 

If I make a minor alteration, I'll convert the screws into camlocks.  Maybe every other.  Suffer once and call it good.

[aviatoreb]

17 minutes ago, FlyingDude said:

Guys, frankly, I don't give a rodent's rear about the oneness of the piece.  3 is not too many.  Actually, smaller is easier to clean than a huge one.  Sheets #2 and #3 from front could be joined, at most, reducing the number to 2.  I wouldn't want a humongous sheet lying on top of me while I'm under the plane trying to stick the front of the sheet between the stringers and aft of the nose gear door, and screwing in the first pilot screws to hold it in place.  However, the multitude of the fasteners is shocking. 

If I make a minor alteration, I'll convert the screws into camlocks.  Maybe every other.  Suffer once and call it good.

I agree with you.

And power screw drivers even more so.

The ONLY advantage I can figure of the one piece is to hide antenna - but why cant someone make a small nonmetallic panel shaped as already have to hide antenna.

And save 10k in labor to convert.

The idea of spending 10k to save a little bit of time and money with the screw driver at annual doesn't add up.  As a speed mod - its just the antenna right?  And its not a big speed mod bang for the buck.

[FlyingDude]

16 minutes ago, aviatoreb said:

to hide antenna

I thought that was due to the materials used, not the oneness. I haven't seen a one piece yet, so I don't know if the fasteners that run laterally are still there. 

I would do the labor (under supervision) so to me, it's like suffering for 2 days one time but then never worrying about spending hours on the bottom panels in the future.