1969 piper Cherokee weight and balance??

jmarine225

jmarine225

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Jmarine225
I’m curious if anyone can help me with this. Without getting crazy and inputting all of the data, my weight and balance states my cg is too far forward anytime two of us are in there don’t seats, even filled to the tabs. We found it’s definitely not the case because the plane easily climbs nose high and then some. I’ve added weight to the baggage area just in case and it was like a rocket shooting nose up. Now I have my tanks filled
(50 gallons)and the cg is really forward. Curious if something is off, if all Cherokees are like this and if it’s okay to fly with the filled tanks and weight in the back, yet not overweight. I’ve compared my data to similar 140’s and it seems my arm for the front seats is shorter by a few reasons for some reason. I’m also going off a handwritten w&b provided when I purchased the aircraft.
 
Step 1 - go to the FAA website and download the TCDS for the cherokee 180. It contains the legal location of each point for determining the W&B and CG. Do not compare to a 140 and do not depend on the handwritten W&B. AROW, remember?

Step 2 - find an A&P with certified scales to create a legal W&B.
 
murphey said:
Step 1 - go to the FAA website and download the TCDS for the cherokee 180. It contains the legal location of each point for determining the W&B and CG. Do not compare to a 140 and do not depend on the handwritten W&B. AROW, remember?

Step 2 - find an A&P with certified scales to create a legal W&B.
Click to expand...
Yeah my plan is to get it weighed out. The numbers don’t make sense with how the plane flies. As far as the FAA website, does it contain the data for a 140? Or, is there a location I can find the arms for the 140? The 1969 owners Manual is no help.
 
So these numbers are good for the 140 also? Looking online my arms are different than all other 140’s.
 
In order to be legal, you are required to carry a current empty weight and balance document with other paperwork in your plane. You should have a copy in the plane, if not, you should look in your aircraft log book and find the last log entry with weight and balance. Then, use the type certificate data sheet on your make, model and serial number to determine if your plane is within limits.
 
jason gula said:
I’m curious if anyone can help me with this. Without getting crazy and inputting all of the data, my weight and balance states my cg is too far forward anytime two of us are in there don’t seats, even filled to the tabs. We found it’s definitely not the case because the plane easily climbs nose high and then some. I’ve added weight to the baggage area just in case and it was like a rocket shooting nose up. Now I have my tanks filled
(50 gallons)and the cg is really forward. Curious if something is off, if all Cherokees are like this and if it’s okay to fly with the filled tanks and weight in the back, yet not overweight. I’ve compared my data to similar 140’s and it seems my arm for the front seats is shorter by a few reasons for some reason. I’m also going off a handwritten w&b provided when I purchased the aircraft.
Click to expand...
As was said, get the TCDS for your bird. Maybe even download it.
Go to the FAA home page. Click "Aircraft" Then down to "Aircraft certification". scroll down to "Design approval resources" At the bottom of the page, click on "Type Certificate Data sheets"
You are taken to the TCDS page. Find Piper, then your model. Ta Da. Beware, TCDS seems to be moved around the FAA home page often. Good luck.
 
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On the 140 I fly if there are two 200 pounders up front it won’t take full fuel and would still be very close to forward CG when filled to the tabs. It has the small rear seats and adding someone back there would put it over gross.

Just because it’s up to the forward limit of CG doesn’t mean you it won’t “easily climbs nose high and then some.” It’s a limit for another reason, not that it suddenly won’t pitch up.

When the rear seats are occupied (and CG is still well within limits) the decrease in stability is noticeable.

Get a legal W&B. I wouldn’t fly it until you know for sure you are in CG!
 
Does your weight and balance graph have two chamfers in the upper left corner or just one?
Also, I believe that the front seat datum is for the front hole position and you can make adjustments for it as you move your seat to further rearward hole positions.
 
EdFred said:
Does your weight and balance graph have two chamfers in the upper left corner or just one?
Also, I believe that the front seat datum is for the front hole position and you can make adjustments for it as you move your seat to further rearward hole positions.
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I’m using the one on foreflight and it has two. Others I’ve seen online for the 140 have one. Totally confusing.
 
jason gula said:
I’m using the one on foreflight and it has two. Others I’ve seen online for the 140 have one. Totally confusing.
Click to expand...

You want the one with two chamfers. I think each hole position on front seat is a 2in change. What happens if you calculate the weight and balance with your front seats in the rear position? I sold my 69 Cherokee 180 in 2008 so I'm going from memory on this.
 
jason gula said:
The numbers don’t make sense with how the plane flies.
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FYI: the numbers don't relate to how the aircraft flies, rather it relates to control authority, i.e., whether you run out control movement, when you get to the edge of the flight envelope. Not a good place to be.
 
EdFred said:
What happens if you calculate the weight and balance with your front seats in the rear position?
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Doesn't matter if his certified empty weight is not accurate which from his statements leaves that in doubt.;)
 
What serial number is your 140? Or, to the closest 50 or 100 if you’d rather not reveal that.
 
Maxnr said:
As was said, get the TCDS for your bird. Maybe even download it.
Go to the FAA home page. Click "Aircraft" Then down to "Aircraft certification". scroll down to "Design approval resources" At the bottom of the page, click on "Type Certificate Data sheets"
You are taken to the TCDS page. Find Piper, then your model. Ta Da. Beware, TCDS seems to be moved around the FAA home page often. Good luck.
Click to expand...
Max....I posted the direct link to download the TCDS for Jason. IMNSHO, I think it's one of those reports that every owner (maybe even renters?) should always have in their collection of documents. Know what else tablets are handy for, besides Garmin/WingX/ForeFlight/whateever? Keeping PDF copies of the stuff for the airplane, just in case you need to land someplace for maintenance. You got the parts manual? No problem if the local shop doesn't have it for your airplane, or you're someplace without a shop - you got the parts manual, a phone, and you can order what you need while trying to find an A&P. Within reason, of course. You're not going to order the engine, or even a couple cylinders, but for smaller stuff, sure does come in handy.

Having the TCDS with you eliminates arguments with CFIs who claim "oh, another 2 big guys in the back seat won't cause a CG problem...."
 
EdFred said:
You want the one with two chamfers. I think each hole position on front seat is a 2in change. What happens if you calculate the weight and balance with your front seats in the rear position? I sold my 69 Cherokee 180 in 2008 so I'm going from memory on this.
Click to expand...
So with this, each hole the seat is moved back from the front I could move that arm by two inches? Just curious here though I’m going to have to just go out and waste 15 gallons of fuel.
 
jason gula said:
So with this, each hole the seat is moved back from the front I could move that arm by two inches? Just curious here though I’m going to have to just go out and waste 15 gallons of fuel.
Click to expand...
If my memory serves correct yes. But I would verify that.
 
Bell206 said:
Doesn't matter if his certified empty weight is not accurate which from his statements leaves that in doubt.;)
Click to expand...
A weight and balance was last completed approximately 16 years ago. I think it’s time for a new one.
 
jason gula said:
I’m curious if anyone can help me with this. Without getting crazy and inputting all of the data, my weight and balance states my cg is too far forward anytime two of us are in there don’t seats, even filled to the tabs. We found it’s definitely not the case because the plane easily climbs nose high and then some. I’ve added weight to the baggage area just in case and it was like a rocket shooting nose up. Now I have my tanks filled
(50 gallons)and the cg is really forward. Curious if something is off, if all Cherokees are like this and if it’s okay to fly with the filled tanks and weight in the back, yet not overweight. I’ve compared my data to similar 140’s and it seems my arm for the front seats is shorter by a few reasons for some reason. I’m also going off a handwritten w&b provided when I purchased the aircraft.
Click to expand...

There should be a logged empty weight and arm in your logbook, modifying any original W&B document that came with your plane. You need that number to be legal to fly. It is possible that there was an error in computation of the modified W&B at some point, but you would have to go through the logs to find and verify it. The proper arms for various stations can be found in the TCDS if not in the POH or owner's manual. It's been a long time since I flew a Cherokee 140, but I don't remember flight planning with two so that it was beyond the forward CG. My Grumman will come close to, but not beyond the forward CG with two relatively hefty individuals aboard.
 
The numbers should be in your AFM as well as the TCDS. I have a 1969 140 and I can put two 200 lb people in the front and be just at the edge of the envelope with full fuel. I never fill it past the tabs so that gives me an extra 90lbs and puts me in the Utility category.

https://touringmachine.com/Cherokee/W&B.php?plane=N7290J

Here’s the TCDS. You need to read carefully to see the ARMs.
Cherokee 140 TCDS 1.png Cherokee 140 TCDS 2.png
 
JScarry said:
The numbers should be in your AFM as well as the TCDS. I have a 1969 140 and I can put two 200 lb people in the front and be just at the edge of the envelope with full fuel. I never fill it past the tabs so that gives me an extra 90lbs and puts me in the Utility category.

https://touringmachine.com/Cherokee/W&B.php?plane=N7290J

Here’s the TCDS. You need to read carefully to see the ARMs.
View attachment 88123 View attachment 88124
Click to expand...
Well that was helpful. In comparison. MY empty weight is heavier and arm is 84.4 which is much more forward than most. That’s what Is on my w&b paperwork from the last weigh.
 
jason gula said:
arm is 84.4 which is much more forward than most. That’s what Is on my w&b paperwork from the last weigh.
Click to expand...
So, two possibilities. Someone ****ed up and wrote down the wrong arm, or someone took a sawzall to the fuselage between the seats and firewall and shortened it by 1.1 inches.
 
It is a good idea to check the math on previous equipment changes to weight and balance whenever figures seem out of line. I have found math errors more than once.

When I was in A&P school, someone donated a nice single seat composite airplane to the school...reason was the plane did not fly well and owner was not happy with it. After a review of the weight and balance document, I found that the owner had made a serious math error..the plane was shown to be within normal limits but was actually very aft cg...ballast up front would have made the plane fly much better.
 
Capt. Geoffrey Thorpe said:
So, two possibilities. Someone ****ed up and wrote down the wrong arm, or someone took a sawzall to the fuselage between the seats and firewall and shortened it by 1.1 inches.
Click to expand...
So should the arm be 85.5 then?
 
I used to fly an airplane like that, the weight and balance data made it really hard to keep in CG. After some research, a previous weight and balance form had two of the numbers for the empty arm transposed - something like 83.7 instead of 87.3 - which threw off all the other calculations. Had been flying that way for years, with people discussing putting ballast in it, all kinds of solutions. But it was just a math error.
 
fwiw - my '74 cherokee 140 was nose-heavy (the AC unit didn't help). I always had to be careful about bumping up against the forward CG limit before I worrying about max gross weight.

btw - as part of an extensive "annual" (engine overhaul, swapping alternators, removing some equipment, etc), I had the aircraft weighed and it actually gained weight.

Good luck with the airplane. I really enjoyed owning and flying my 140.
 
jason gula said:
My aircraft is actually in page 12. East seat numbers are correct but front are wrong. Thanks for the help.
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Edited the previous post. Front seats in all the PA28 series are +85.5
 
The 1962 Cherokee I was trying to learn how to land has an “owner’s manual” that does NOT include W&B. That data is in a separate document. (Had to bug the instructor to find and show it to me - it was stored with the airplane/ engine logs.)
There was a current W&B report in the plane, but no way to calculate or graph anything. Maybe a ‘69 is documented the same way.
 
Another thing to watch for is modifications. An Isham STOL kit modification changes the aft CG limit as documented in the STC.
 
I have a 64 piper Cherokee 180 and it is nose heavy. If you put 2 200 pound guys in the front and full of fuel, the CG is probably going to be too far forward. Usually only about 20 or 30 pounds in the baggage compartment solves the problem. My 180 will haul 800 lbs full of fuel, so having 20 lbs in the baggage if you only have 2 onboard is really no big deal.
 
It can happen in a Cherokee but both guys gotta be pretty seriously + sized. Can be fixed by a a flight bag or something heavyish in the luggage bay
 
Super useful thread guys. I looked through the POH like three times looking for arm data. Now I have some new leads to chase down.
 
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