Really High Empty Weight?

[smmilke]

I've been looking into the weight of other people's BC-12Ds and it looks like mine weighs 70 lbs more than most. I'm not sure about the cg, but I think it is a bit tail heavy considering I have the extended engine mount. My empty weight is 891 lbs and cg is 17.3 inches, if I remember correctly. Just so you can compare, here is what I've got:

'46 BC-12D-4-85
Gilberti STC
No starter
B&C lightweight alternator
small scooter battery under the seat
Scott 3200 tailwheel
8.50X6, no wheel pants
Metal prop
pretty sparse interior, no headliner or door upholstery, some Airtex upholstery on the firewall and side panels under the instrument panel

I removed all the wiring for lights and have scoured under nearly every panel and plate to try to find unnecessary weight. I read another thread on the weights of these things and the average was around 820. I've never heard of a T-craft as heavy as mine (unless is was well above 85 hp). I asked the guy who did the rebuild in the '90s about it and he said he had never done a paint job before and went pretty heavy on the silver and the paint. I can't imagine the paint making 70 lbs difference.

Any ideas on what makes this thing so heavy? I would also like to get an idea of what the average empty cg is, especially with the long engine mount.

[skip]

Re: Really High Empty Weight?

I've been looking into the weight of other people's BC-12Ds and it looks like mine weighs 70 lbs more than most. I'm not sure about the cg, but I think it is a bit tail heavy considering I have the extended engine mount. My empty weight is 891 lbs and cg is 17.3 inches, if I remember correctly. Just so you can compare, here is what I've got:

'46 BC-12D-4-85
Gilberti STC
No starter
B&C lightweight alternator
small scooter battery under the seat
Scott 3200 tailwheel
8.50X6, no wheel pants
Metal prop
pretty sparse interior, no headliner or door upholstery, some Airtex upholstery on the firewall and side panels under the instrument panel

I removed all the wiring for lights and have scoured under nearly every panel and plate to try to find unnecessary weight. I read another thread on the weights of these things and the average was around 820. I've never heard of a T-craft as heavy as mine (unless is was well above 85 hp). I asked the guy who did the rebuild in the '90s about it and he said he had never done a paint job before and went pretty heavy on the silver and the paint. I can't imagine the paint making 70 lbs difference.

Any ideas on what makes this thing so heavy? I would also like to get an idea of what the average empty cg is, especially with the long engine mount.

I have a recent weight on non-certified scales (so if anyone notices some minor discrepancy between these numbers and what is in my official weight and balance, these numbers are UNOFFICIAL...)

'46 BC-12D-4-85
Gilberti STC
Standard Delco starter
Standard Delco generator
Battery box for 35 amp battery in baggage as per the STC (really helps with CG)
Scott 2000 tailwheel
6X6, no wheel pants
Metal prop
Full airtex interior, headliner, door upholstery (not much weight, but a little
Radio and Transponder

Empty 910, CG 13.8

You have to remember that the battery and cables add a lot. I have a heavier starter and generator than you so that adds some. I have a bigger battery, but being in the back of the extended baggage compartment, the CG is not too bad. My cover (at the time) was Stitts with a fairly light hand on the silver. Radio and transponder and associated wiring add a bit.

The standard way for measurement was typically to start with book value and compute all changes and additions. I suspect that if most BC12-D's were weighed, they would come out heavier than many expect. That said, if the Gilberti/Harrier/Bowden STC is properly applied, the engineering supports a 1500 lb gross regardless of the route chosen for the official gross weight, so you are not in danger of the wings falling off.

[smmilke]

Re: Really High Empty Weight?

Wow that is surprisingly heavy. I should add that my only electronics are a radio and intercom. The battery I have can't weight more than 2 lbs, and I think the wiring for it is only 12 gauge. I can't believe your cg is so far forward! The truth is I'm not as concerned about the weight as I am the cg, mine is really hard to keep within the aft limit at 1500 lbs. Maybe your tail wheel is a lot lighter and the combo of the starter and generator are a lot heavier than on my plane?

[Pearson]

Re: Really High Empty Weight?

Paint is heavy. If that were my plane, I would water sand it down to the silver with fine grit paper and repaint it with one coat of polyurethane paint. I used to know how much each coat weighted on a small single engine plane, but it has been too long. I would guess at least ten, and maybe twelve pounds or more per coat.

By having extra thick coats of silver and top coats, you will probably get cracking and/or peeling eventually. By sanding it down and recoating it with a single coat of polyurethane, you will not only be losing weight but also getting a longer lasting paint job.

[Guest]

Re: Really High Empty Weight?

I've been looking into the weight of other people's BC-12Ds and it looks like mine weighs 70 lbs more than most. I'm not sure about the cg, but I think it is a bit tail heavy considering I have the extended engine mount. My empty weight is 891 lbs and cg is 17.3 inches, if I remember correctly. Just so you can compare, here is what I've got:

'46 BC-12D-4-85
Gilberti STC
No starter
B&C lightweight alternator
small scooter battery under the seat
Scott 3200 tailwheel
8.50X6, no wheel pants
Metal prop
pretty sparse interior, no headliner or door upholstery, some Airtex upholstery on the firewall and side panels under the instrument panel

I removed all the wiring for lights and have scoured under nearly every panel and plate to try to find unnecessary weight. I read another thread on the weights of these things and the average was around 820. I've never heard of a T-craft as heavy as mine (unless is was well above 85 hp). I asked the guy who did the rebuild in the '90s about it and he said he had never done a paint job before and went pretty heavy on the silver and the paint. I can't imagine the paint making 70 lbs difference.

Any ideas on what makes this thing so heavy? I would also like to get an idea of what the average empty cg is, especially with the long engine mount.

My bc12d with A65, metal prop, 2 wing tanks, dual brakes, swivel tail wheel, elt, ROC, clock, large rear windows and skylights is EW=834 lbs, EWCG=+18.87.

I think that most come out heavy because the original weights were calculated not scale weighed.

Dave

[smmilke]

Re: Really High Empty Weight?

I know the when the paint was removed on the 150 I used to own the EW changed by 15 lbs, but I would think it might be a bit heavier on a fabric airplane. I still can't imagine it being 30 extra lbs, especially since the paint really doesn't look that thick compared to most paint jobs I've seen.
These threads give a lot of measured weights and mine still seems heavy, but I would agree that there is a discrepancy between original weights and those measured shortly after.

http://vb.taylorcraft.org/showthread.php?8880-BC12-D-Empty-weight&highlight=empty+weights

http://vb.taylorcraft.org/showthread.php?3990-Taylorcraft-Empty-Weight&highlight=empty+weights

I was trying to think of other things that would make my empty cg aft. My extended baggage has sheet aluminum covered in cloth bolted to the four "walls" and the floor is a big sheet of some kind of ply wood. I took out some of the aluminum panels and thought they were surprisingly heavy, but I'm not sure how much weight I can really save there. What do you guys have to form the walls of your baggage area?

[M Towsley]

Re: Really High Empty Weight?

I have the stock canvas sling. Works for me and is relatively light.

[Guest]

Re: Really High Empty Weight?

I removed almost all of the plywood that was in the baggage area to move the CG forward. I left only pieces around the rear windows and used a baggage sling. It helped.

I recall weighing wings after covering and doping. I think dope only added 5 lbs per wing.

Dave

[smmilke]

Re: Really High Empty Weight?

You guys are referring to slings in the original baggage compartments right? I have the extended baggage which would make for a pretty big sling!

[M Towsley]

Re: Really High Empty Weight?

I am, yes.

Everything behind the CG is going to make it more tail heavy. If there is nothing out of the ordinary besides your extended storage and paint I wouldn't know what you can do to eliminate it. Big piece of wood, that may be heavy, and aluminum may be a partial culprit.

[Guest]

Re: Really High Empty Weight?

I put in the standard 50 lb. sling. The big baggage area is just a for show in my a/c. My sling is cabin width and about 14" in the fore-aft direction.

[cvavon]

Re: Really High Empty Weight?

My 1940 has a seat sling and baggage sling that is made out of some kind of synthetic nylon material very light Thin cushions on the seat fabric head liner and thats it for the inside.My wings are 41 deluxe 15 rib pre war stick built ribs 2 wing tanks light weight starter and alternator Oddysey battery empty scale weight 776 with 67 lbs on tali wheel and the cg 16.1 with fuel and two people 17.2 oh thats with disk brakes and 3200 ak bush tail wheel and 26 in bush wheel tires they can be light.

[Pearson]

Re: Really High Empty Weight?

Shaun,

It is fairly common for the tubes at the aft end of the fuselage to rust out on Taylorcraft. It may be possible that someone repaired your tailpost and/or rear section of lower longerons and added a bunch of weight in the process. Even that should not add 30 or 40 pounds to your empty weight, but it could be part of the problem.

[Joe cooper]

Re: Really High Empty Weight?

Shaun,

It is fairly common for the tubes at the aft end of the fuselage to rust out on Taylorcraft. It may be possible that someone repaired your tailpost and/or rear section of lower longerons and added a bunch of weight in the process. Even that should not add 30 or 40 pounds to your empty weight, but it could be part of the problem.

It's the paint. Paint is HEAVY! Repairs to the tail could not possibly have caused this. I recently passed on a very nice, well done 85 hp as it weighed 900 . Magnificent paint and workmanship. Lots of paint.

[cvavon]

Re: Really High Empty Weight?

Has any one put a gallon can of paint on a scale and weighed one I am curious what it would be. and how many gl does it take to paint a plane from bare fabric 5 or 6 gl??