Finding Cessna arms

Discussion in 'Pilot Training' started by airpix, Sep 22, 2009.

  1. airpix

    airpix Filing Flight Plan

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

    Thanks, Airpix
     
  2. dmccormack

    dmccormack Touchdown! Greaser!

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    Have you tried -- Approved Pilot Operating Handbook?
     
  3. airpix

    airpix Filing Flight Plan

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    Yes, The POH list the moment for a "sample plane" but not the arms.
     
  4. dmccormack

    dmccormack Touchdown! Greaser!

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    If you have the moment and the weight, you can calculate the arm, right?
     
  5. airpix

    airpix Filing Flight Plan

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    Right. I have the empty weight and moment but not the actual moments (or arms) for the other stations.
     
  6. AuntPeggy

    AuntPeggy Final Approach

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  7. dmccormack

    dmccormack Touchdown! Greaser!

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    Usually (though not always) there is a Weight and Balance supplement to the airplane's POH that provides actual W&B data for that airplane.

    ...and -- welcome to POA!
     
  8. RMCN172RG

    RMCN172RG Pattern Altitude

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    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.
     
  9. dmccormack

    dmccormack Touchdown! Greaser!

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    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.
     
  10. RMCN172RG

    RMCN172RG Pattern Altitude

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    Gets real messy after thirty years:D

    That's what a home computer is for:rolleyes:
     
  11. dmccormack

    dmccormack Touchdown! Greaser!

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    That's the best option -- though the legal-types may argue that the homemade spreadsheet printout is somehow not "official" (under the same suspect category as "homemade checklists")
     
  12. TangoWhiskey

    TangoWhiskey Touchdown! Greaser!

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    I saw the subject line and thought he was looking for wing-mounted rockets...
     
  13. steingar

    steingar Taxi to Parking

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    Personally I think the Cessna's arms would be found in its sleeves.
     
  14. B2Soar

    B2Soar Pre-takeoff checklist

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    I wondered when Cessna started to make weapons and what they were?:confused:
     
  15. Clark1961

    Clark1961 Touchdown! Greaser!

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    Well maybe it's been dis-armed which is why he's looking for'em.
     
  16. poadeleted20

    poadeleted20 Deleted

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    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).
     
  17. dmccormack

    dmccormack Touchdown! Greaser!

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    Give a man a fish, he eats for a day, teach a man to fish....
     
  18. Clark1961

    Clark1961 Touchdown! Greaser!

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    Armless fishing could be just a bit difficult. How's 'e gonna tie on the 'ook?
     
  19. dmccormack

    dmccormack Touchdown! Greaser!

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

    [​IMG]
     
  20. Clark1961

    Clark1961 Touchdown! Greaser!

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    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!
     
  21. Doggtyred

    Doggtyred En-Route

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    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).
     
  22. airpix

    airpix Filing Flight Plan

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    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
     
  23. airpix

    airpix Filing Flight Plan

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    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.




     
  24. dmccormack

    dmccormack Touchdown! Greaser!

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    Yes, my expertise is based on my observation of the "Drunken Fisherman Floatplane Regatta."
     
  25. Capt. Geoffrey Thorpe

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    Teach him how to use the internet and he won't bother you for weeks.
     
  26. Peter Sawiris

    Peter Sawiris Filing Flight Plan

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    Below the shoulders?
     
  27. Stan Cooper

    Stan Cooper Line Up and Wait

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  29. Stan Cooper

    Stan Cooper Line Up and Wait

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    Last edited: Feb 2, 2019
  30. Tom-D

    Tom-D Taxi to Parking PoA Supporter

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    great ya got another one