Finding Cessna arms

airpix

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Airpix
Where can I find specific arms for a Cessna 172K (1969) weight and balance? Front seat, rear seat, baggage, fuel.

Thanks, Airpix
 
Yes, The POH list the moment for a "sample plane" but not the arms.
 
Right. I have the empty weight and moment but not the actual moments (or arms) for the other stations.
 
It may be different for your older plane but for my 1980 172RG the POH has generic data. The actual W&B sheet up to date with the actual equipment list is kept with the maintenance logs.
 
It may be different for your older plane but for my 1980 172RG the POH has generic data. The actual W&B sheet up to date with the actual equipment list is kept with the maintenance logs.

True. It's a good idea to transfer the W&B data to the POH -- either with a facsimilie or simple pen entry into the worksheet page.
 
I wondered when Cessna started to make weapons and what they were?:confused:
 
Where can I find specific arms for a Cessna 172K (1969) weight and balance? Front seat, rear seat, baggage, fuel.
The ancient-style owner's manual for a 1969 172K may not have that data, and it predates the more detailed AFM/POH's required starting in 1978 which must have it. Back then, Cessna just gave a graph with weight on the x-axis, moment on the y-axis, and lines of varying slopes for each item (front seat, rear seat, baggage, and fuel). However, reference to Page 8 of the Cessna 172 TCDS tells us the arms for the K-model are:

Front seat: +34 to +46.2 (depending on how far forward/back it is on the track -- you'll have to measure where you put the seat)
Rear seat: +73
Baggage area: +95
Fuel: +48

BTW, that TCDS covers all 172 models from the original C-172 through the most recent C-172S (including the T-41's produced for the USAF).
 
The ancient-style owner's manual for a 1969 172K may not have that data, and it predates the more detailed AFM/POH's required starting in 1978 which must have it. Back then, Cessna just gave a graph with weight on the x-axis, moment on the y-axis, and lines of varying slopes for each item (front seat, rear seat, baggage, and fuel). However, reference to Page 8 of the Cessna 172 TCDS tells us the arms for the K-model are:

Front seat: +34 to +46.2 (depending on how far forward/back it is on the track -- you'll have to measure where you put the seat)
Rear seat: +73
Baggage area: +95
Fuel: +48

BTW, that TCDS covers all 172 models from the original C-172 through the most recent C-172S (including the T-41's produced for the USAF).


Give a man a fish, he eats for a day, teach a man to fish....
 
Armless fishing could be just a bit difficult. How's 'e gonna tie on the 'ook?

You zoom along the water on floats and knock out the fish coming to the surface...

kodiak-float-plane_387.jpg
 
You zoom along the water on floats and knock out the fish coming to the surface...

kodiak-float-plane_387.jpg

Well...it's obvious that you're the expert in these matters so it just my opinion...but I'd think that approach would interfere with the beer drinking that is a required part of fishing.

You know the saying, give a man a fish and he's fed for the day, teach a man to fish and he'll drink all your beer!
 
Yes, The POH list the moment for a "sample plane" but not the arms.

Moment is weight x arm length.

Do some math.
You should be able to calculate the individual arms of each and every station that has a moment product reported.

If you need to plug something in, use nice round numbers like 100 lbs (in the seats) or 10 lbs (baggage)

Remember fuel is 6 lbs/gallon for avgas.

Calculating such a value is perfectly within the skillset of someone who wants to be a pilot.

If you are willing to do the work to figure it out on your own, I'm sure several people here would be willing to VERIFY it (rather than do it for you).
 
Hi Ron, Thanks for the Type Certificate Data sheet link. This is exactly what I was looking for, the precise arm locations. As previously mentioned the 1969 Owners Manual leaves much to be desired.

Airpix
 
I did some math, that's why I posted the original question. Without the arm locations in the 1969 manual I divided moment by weight in the "sample airplane" graph (pge 3-4) and for the rear seat got a arm of 70. Well come to find out that was the arm for the previous 172 models and not the K whose rear seat arm, according to the TCDs, is actually 73! Cessna must have been in a rush to get the manual out in 69 and copied the previous years manual, ha.




Moment is weight x arm length.

Do some math.
You should be able to calculate the individual arms of each and every station that has a moment product reported.

If you need to plug something in, use nice round numbers like 100 lbs (in the seats) or 10 lbs (baggage)

Remember fuel is 6 lbs/gallon for avgas.

Calculating such a value is perfectly within the skillset of someone who wants to be a pilot.

If you are willing to do the work to figure it out on your own, I'm sure several people here would be willing to VERIFY it (rather than do it for you).
 
Well...it's obvious that you're the expert in these matters so it just my opinion...but I'd think that approach would interfere with the beer drinking that is a required part of fishing.

You know the saying, give a man a fish and he's fed for the day, teach a man to fish and he'll drink all your beer!

Yes, my expertise is based on my observation of the "Drunken Fisherman Floatplane Regatta."
 
great ya got another one
 
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