W&B - 975 @ 11.59 (FWD CG Limit is 12.3) & Potential Weight Saving Items

[6643]

I'll always be out of the forward tolerance unless I'm full fuel. (REF. IMG_1605, IMG_1606)
*This is with the current empty weight CG at 11.69

I'll be always outside of tolerance with 3.5g of fuel (minimum VFR + unusable fuel) unless the empty weight CG is >=12.7 (REF. IMG_1607)

Yeah, I know. I already ran some numbers with your spreadsheet. I don't have an answer for you, other than a possible error in the spreadsheet itself.

Question:
On a 2 points landing, it's impossible to do a nose over without the extender even if I put to much forward pressure on the yoke.
The nose over will only happen if I hit a bump or I ride the brake too hard.
This is correct?

No, you can nose it over, with or without the extenders. It's just a lot harder with them on. If you land with the brakes applied on a hard surface it'll nose over pretty easily. On the other hand, if you keep the tail low and stay of the brakes, it's not going to nose over just because you hit a bump.

On the other hand, the extenders impart a twisting moment on the gear, which causes changes in the toe angle of the wheels and can make it a lot easier to take a turn for the weeds.

While you're getting familiar with it, it's a good idea to avoid going anywhere that will require aggressive braking. There's no shame in a well executed go-around.

There are drawings and descriptions of the gear legs and a discussion of the extenders in this thread.

[maverick_fa]

So, I'd suggest you level it using the horizontal overlap that runs the length of the fuselage, hang a plum-bob off the wing leading edge and measure to your mains and tail wheel. From this you can calculate the C of G.

I'll definitely do that.

I don't have an answer for you, other than a possible error in the spreadsheet itself.

Maybe but my spreadsheet is working for all other AC that I flown. I also did the manual calculations with the W&B on the website & I end up with the same result...

I'll do the troubleshooting probably next week when I'll get the airplane.

No, you can nose it over, with or without the extenders. It's just a lot harder with them on. If you land with the brakes applied on a hard surface it'll nose over pretty easily. On the other hand, if you keep the tail low and stay of the brakes, it's not going to nose over just because you hit a bump

Thanks for the clarification & thanks for sharing the document for the gear leg!

[cdoughty]

You might also check the chain of calculations from the last weighing as things were added and subtracted. I have seen lots of small errors in these updates.

Also on my plane in 3pt ground attitude it wont flow fuel below about 1.5 gals per side. So at 3.5 gals you could easily get the fuel "unporting" on climb out with a go around. Perhaps others disagree, but I wouldn't fly that low on fuel. Perhaps a higher limit would solve some of your problems.

[maverick_fa]

You might also check the chain of calculations from the last weighing as things were added and subtracted. I have seen lots of small errors in these updates.

Also on my plane in 3pt ground attitude it wont flow fuel below about 1.5 gals per side. So at 3.5 gals you could easily get the fuel "unporting" on climb out with a go around. Perhaps others disagree, but I wouldn't fly that low on fuel. Perhaps a higher limit would solve some of your problems.

Thanks cdoughty!
I did the ferry flight today. It was a blast!!
I'll empty the oil & fuel wing level when I'll carry out the W&B.
I agree the difference between low level fuel on take off & for lading... I'll never TO with a low level fuel but I might come back with minimum fuel... & I want to know if I'm still in the limit of the flight envelope (forward CG).

Not sure about the calculations but I believe the kept the gear extender, oil & probably some fuel (3 points attitude).

I'll keep you posted.

[8424]

Hi Mat.

Glad you had a good first flight. Lots of fun ahead!

I recently had an official W&B done, and the oil had to be in the engine as it is included in the empty weight. Wing tanks had to be empty.

Steve A H

[6643]

Planes of the era did not include the oil in the empty weight. It's only a convention, though. You're not going to fly without oil, so no reason not to weigh the plane with oil on board. Subtract it out if you want to be period correct.

The easiest way to deal with fuel is to fill the tanks completely and weigh the plane that way, then subtract out the weight and arm of 25 gallons.

Level the plane and drop a plumb line from the leading edge of the wing(s) to establish the datum. Then, measure the exact arms of the mains and the tailwheel.

[8424]

Sorry, Mat, for steering you wrong on the oil being included in the empty weight of our planes. John (6643) is really good for me...he keeps me on the straight and narrow! I did find the actual reference John is using in FAA-H-8083-1B, Weight and Balance Handbook, Chapter 3: Oil The empty weight for aircraft certificated under the Civilian Air Regulations (CAR) part 3 does not include the engine lubricating oil.

I actually like the idea of subtracting 11 pounds off my empty weight, but I'll stick with the paperwork from the W&B guy.

Steve A H

[maverick_fa]

Usually, it's mentioned in the POH (W&B section) if the oil is part of the Basic Empty Weight or not.
Oil isn't part of the Basic Empty Weight IAW the C140 W&B sheet (see attached file).

Full Oil is part of the Basic Empty weight for the C152 as an example.

The full fuel is a good tricks.

[maverick_fa]

I decided to put my 140 on diet from the instrument panel forward & I expect to get in the CG tolerance range when I'll be done with the mods as per my calculations (for entertainment use only).
I'll properly weight my AC (hopefully this summer)... the last time that she was officially weighted was in 1970...
She probably weight way more than I was thinking...

FYI, she was already with a forward CG back in the 1970... since them a huge 35A generator have been added on the top of the heavy prop (69CK-0-48L)

Question:
On the W&B for the Pilot/PAX. The 19.5 arm is it for full aft or full forward seat adjustment position.