weight and balance

[astjp2]

I just emailed off a weight and balance worksheet in .xls, I am hoping it will get posted where the 337's are, I was suprised that my airplane is way nose heavy when I put in my as weighted numbers in, I can put in 200 lbs of baggage with the short mount and still be within CG, over gross but still within CG limits. Weird, for the factory to went a longer mount, I calculated that if I went with the long mount, I would be way too far foreward and outside the limits using a -8 engine. It was fun to play with a loading schedule. oh well...Tim

[Hank Jarrett]

Re: weight and balance

Might want to run the numbers again manually. I have a 41 and if I could be in CG range with 200# in the baggage sling the plane would tip up on its prop empty. Something is VERY wrong here!
Hank

[Howard Wilson]

Re: weight and balance

Might want to run the numbers again manually. I have a 41 and if I could be in CG range with 200# in the baggage sling the plane would tip up on its prop empty. Something is VERY wrong here!
Hank

Yeah, there's an extra zero in there somewhere. You can climb or dive just by moving your arm forward or back.

[astjp2]

Re: weight and balance

I took the measurements from the TCDS, It will be way over gross but still within CG for my airplane. I can email you the excel template, its real simple, just fill in the blocks for your airplane....Tim

[Hank Jarrett]

Re: weight and balance

Tim,
Check your PM. I sent my email for your spreadsheet. Something just ain't right here.
Hank

[Hank Jarrett]

Re: weight and balance

Tim,
I ran your numbers through my spreadsheet and my numbers through your spreadsheet and everything looks fine to me (you have a nice light plane there! 720# is a GOOD one!) Our distances don't quite match up, your arm to the mains is 2" while mine is 2.5", and your tail moment is 193" and mine is 198". That could be different springs on the tail or different tail wheels and one of us may not have been perfectly level for the mains, but it didn't result in that big a difference. I calculated all four ways with the CG within range (from 14.2 to 20" behind the leading edge). With 200# in the baggage compartment the plane was WAAAAAAAY tail heavy. I don't know how you got it to show within range with all that weight back there but I suspect a "finger fumbel" typing in the numbers. Your spreadsheet looks fine to me.
When I first did mine I backed into the moments to see how accurate they were. I did a true EMPTY W&B by doing one when there was NO oil or fuel anywhere, then added the 4 qts of oil and did it again to make sure the CG of the oil was right. I them added 12Gal of fuel and did it again to make sure the main tank was really at -9". I followed that with one with me in the cockpit to see if my belly moved MY CG forward from 23" (it did, but not enough to worry about). I continued to include the battery, voltage regulator, wind generator, intercom/hand held/headsets and even messed with the raised seat cushons I never use. What I found out was everything moved the CG around a little, but not enough to worry about from the "book" numbers. I have since repainted, taken a bunch of JUNK out, put in an all new panel (original) and new interior. I plan to do the W&B thing again with the new lower GW just for fun. I started out with 799# and hope I can get mine down to your 720! Taking 80# out should make her fly even better.
Hank

[astjp2]

Re: weight and balance

Hank, My airplane is 910, I was just plugging in some number for comparison. Try 410 on the left, 440 on the right and 60 for the tail. I took the arms from the TCDS, but when i weighed it, it was .02 degrees from level on the left horizontal. It still is within I think.
I think that I really screwed up somewhere because I felt that I am 100 over what I should be. I went to Hydraulic toe brakes, but that was only about 20 lbs. I followed the Stits manual to the letter, and used poly tone instead of eurothane. I will know better for next time to be more careful.
Tim

[Guest]

Re: weight and balance

Tim,
I ran your numbers through my spreadsheet and my numbers through your spreadsheet and everything looks fine to me (you have a nice light plane there! 720# is a GOOD one!) Our distances don't quite match up, your arm to the mains is 2" while mine is 2.5", and your tail moment is 193" and mine is 198". That could be different springs on the tail or different tail wheels and one of us may not have been perfectly level for the mains, but it didn't result in that big a difference. I calculated all four ways with the CG within range (from 14.2 to 20" behind the leading edge). With 200# in the baggage compartment the plane was WAAAAAAAY tail heavy. I don't know how you got it to show within range with all that weight back there but I suspect a "finger fumbel" typing in the numbers. Your spreadsheet looks fine to me.
When I first did mine I backed into the moments to see how accurate they were. I did a true EMPTY W&B by doing one when there was NO oil or fuel anywhere, then added the 4 qts of oil and did it again to make sure the CG of the oil was right. I them added 12Gal of fuel and did it again to make sure the main tank was really at -9". I followed that with one with me in the cockpit to see if my belly moved MY CG forward from 23" (it did, but not enough to worry about). I continued to include the battery, voltage regulator, wind generator, intercom/hand held/headsets and even messed with the raised seat cushons I never use. What I found out was everything moved the CG around a little, but not enough to worry about from the "book" numbers. I have since repainted, taken a bunch of JUNK out, put in an all new panel (original) and new interior. I plan to do the W&B thing again with the new lower GW just for fun. I started out with 799# and hope I can get mine down to your 720! Taking 80# out should make her fly even better.
Hank

Hi Hank,

I am perplexed that you get different arms than the TCDS.

The TCDS spells out +2 for mains and +193 for all approved tail wheels.

Does your a/c have mods made that change these arms?

Dave

[astjp2]

Re: weight and balance

He did as measured, not published. There were some descrepancies on the sweep of the gear from what I have been told. The tail wheel model could effect the distance some. Tim

[astjp2]

Re: weight and balance

When I just plugged in my as weighed and put my fat A$$ in with full fuel, 200 lbs baggage, cg was 18.72, the max was 20.0 but I am way over gross.

I just put 450 passengers, 24 fuel, 200 baggage, 910 empty and still had 19.08 cg This give a gross of 1708. So the aircraft would be 508 over the limit.

if anyone wants the spreadsheet, I will email it to them. Its for a bc12-65 Tim

[Guest]

Re: weight and balance

When I just plugged in my as weighed and put my fat A$$ in with full fuel, 200 lbs baggage, cg was 18.72, the max was 20.0 but I am way over gross.

I just put 450 passengers, 24 fuel, 200 baggage, 910 empty and still had 19.08 cg This give a gross of 1708. So the aircraft would be 508 over the limit.

if anyone wants the spreadsheet, I will email it to them. Its for a bc12-65 Tim

so then in this scenerio how much fuel can you burn before the cg moves too far aft?

[Guest]

Re: weight and balance

He did as measured, not published. There were some descrepancies on the sweep of the gear from what I have been told. The tail wheel model could effect the distance some. Tim

I am not sure I believe that the factory is that sloppy. Plus the list of approved tail wheels all list their arm at +193 in teh tcds so there should not be 5" difference between one model and the next unless its stc-ed or field approved.

I suspect its more likely that we folks in the feild are not able to precisly level and measure that might cause a variation like a 1/2".

Dave

[1938BF50]

Re: weight and balance

It's hard for me to stay out of this thread, but.....I think WAY too much credit is given early manufacturers for weights, teqhniques, methods, etc. I personally dont believe there was a prayer in hell that EVERY early Taylorcraft was weighed. Probably with most other manufacturers as well. I'll bet the airworthiness certs for that entire weeks production(of the same engine) would vary no more than a few pounds and MAYBE one plane was actually weighed to satisfy the CAA.

Forrest, Do any of the test logs record empty weight?

[astjp2]

Re: weight and balance

More like the first plane in a series, but I can be wrong, Forrest may know more. Tim

[astjp2]

Re: weight and balance

2 gallons in the header tank, 450 people, 200 baggage, 1572 gross, 20.05 cg
12 gallons wing, 2 header, 450 people, 200 baggage,1644 gross, 20.22 cg

This is sure fun to play with.....Tim