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Thread: flying over gross weight

  1. #41

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    I have a 18A that has a new 18 fuselage. I would like to see a stock 18A frame pics in case I want to do a flat floor mod.
    DENNY

  2. #42
    574cub's Avatar
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    I should be getting off work around 6am when I get home I'll take a couple pictures and post them.

  3. #43

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    Quote Originally Posted by don d View Post
    Stay under aircraft's maneuvering speed and regardless of loads are not going to over-stress the airframe. Wing will stall first.
    ^^^^What he said^^^^

  4. #44

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    The gross weight increase is from Wipair http://www.wipaire.com/modifications/mods-pa18.php also there are a couple of belly pods out there I have the Firman belly pod, this allows you to keep heavy objects forward, and sleeping bags, popcorn and potato chips in the extended baggage

    MTV yes you are correct your stall speed decreases with aft cg, as stated it becomes hard to recover from a stall if max aft cg is past.

    John Pex
    72A
    Chugiak AK

  5. #45
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    My 18A had a ready-rod through the x-brace tube that was not removable without cutting fabric.
    It's a common mod to make the x-brace removable to ease loading/unloading "stuff".

  6. #46
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    Click image for larger version. 

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ID:	16903Here are some of the tubing, the removable rear seat bar and the floor.

  7. #47
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    Good news! Just finished the annual on the J-4. Weighed the plane and was happy to find the plane was 30.0 lbs. lighter than the previously recorded W&B showed. It does have a wooden prop instead of the metal one that was on it at that time, but pretty sure that's not the bulk of it. Perhaps it had wheel pants at one time. Anyways, I'm happy to get that 30#s.

  8. #48
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    Where is that metal prop now? Is it local? Perhaps you could try it in order to answer the performance question for yourself?
    N1PA

  9. #49
    Biotex's Avatar
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    Quote Originally Posted by skywagon8a View Post
    Where is that metal prop now? Is it local? Perhaps you could try it in order to answer the performance question for yourself?
    Long gone. The logbooks show it was replace several years ago.

  10. #50
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    Quote Originally Posted by bob turner View Post
    Be careful with the paperwork, and never unintentionally go out over gross - that means you do not know what you are doing.

    Opinion.

    Damn bob, You are starting to make sense !!! I must be overdosing on my meds again !!!! haha

  11. #51
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    FWIW I did my flight review in that 20# under gross C150 today, it was still "interesting".... All I can say is that I'm glad we didn't do it yesterday.

    I saw some things UP CLOSE that I hadn't even seen before off the end of the runway...... I need to lose at least 30# in the next 2 years and/or take my review early in maybe Feb............................

    Jack

    PS(Edit) I've thought about this and if I had it to do again I'd have Joe pick me up at CBE or wait until he had less fuel. Flying out of 1W3 leaves few good options if the engine quits. I had been waiting 2 months for review, first I was sick, then the 150 down for annual, then weather etc.... We got it done but could have waited longer.

    If anyone is interested look at a sat. shot of 1W3. TO on 27 is straight at Knobly Mt. Normal TO you turn left before another mountain/hill to the left. We could not safely make the turn and flew up Rt.28, first time I had to do so. I laughed and asked Joe where were the turn signals. Bob Turner makes exact correct comment below. thank you O200 for running for another hour.....Joe has confidence in his engine while I've somewhat un nerved. Oh well, we many times depend on the fan not to stop......

    Maybe fly with Joe again this winter and get better time slot for reviews although I'm thinking this may be last flight review......We are all getting old and bailing out, not enough folks at the airport to even tell lies to anymore.......
    Last edited by n40ff; 08-29-2014 at 06:32 AM.

  12. #52

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    Stay out of 150s if you do not have viable engine out fields for just after takeoff. If you and your passenger add up to less than 300#, it might be ok with full fuel. And 172s often lead to grief at high altitude airports, two guys, and their innocent girlfriends. Opinion.

    One comment above has me worried - I am not sure, but I believe maneuvering speed is defined as that speed where, at full gross, the airplane will stall before it breaks with full control deflection, or unusual gust. I believe that actual maneuvering speed varies with weight.

  13. #53

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    Maneuvering speed is lower at lower weights. Counterintuitive.

  14. #54

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    isn't maneuvering speed the airspeed at which full deflection of any 1 flight control surface without risk of structural damage?

  15. #55
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  16. #56
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    That in mind the SUPER 18 is certified at 2300lbs.
    Lots of structural changes in the fuselage and wings on the Super 18.

    Friend of mine flipped his 90hp cub on its back a couple weeks ago. In his paper work to the faa he had to provide w/b at the time of the wreck.

  17. #57

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    I always have that in the back of my mind. Fortunately, nobody has ever asked.

    I keep packets in the seat back, with scenarios that can at least make a Fed happy.

    "Waddaya mean full? Look in there! That tank is at six gallons!"

  18. #58

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    Quote Originally Posted by Canadian Farmer View Post
    isn't maneuvering speed the airspeed at which full deflection of any 1 flight control surface without risk of structural damage?
    Might want to read this very timely article, which states it very well.

    http://www.avweb.com/eletter/archive...t=email#222680

  19. #59
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    Quote Originally Posted by GeeBee View Post
    Might want to read this very timely article, which states it very well.

    http://www.avweb.com/eletter/archive...t=email#222680
    This is a well written article. It brings to mind a question which I have asked several times and not received a learned answer. During my career, I have attended many ground schools for high performance aircraft. All of the airplanes have a list of limitations which must be memorized. One of which is: "Turbulence Penetration Speed M .xxx/xxx KIAS". My questions have been, "Are you supposed to fly at the Turbulence Penetration Speed or below it?". And, "If you are at a lower speed when penetrating turbulence, should you increase speed to the published speed?" The article seems to imply that you should be "AT" the turbulence penetration speed. I was never given an absolute answer. I was usually given a blank stare with a non answer. As a result the number was memorized and we moved on. I just flew carefully and didn't break anything.

    So, what say all you learned pilots, are we supposed to fly at that speed or below it when entering turbulence? Do any of you know for sure? Or, are you just speculating based on your training as described in the article? After more than 50 years, I still do not know.
    N1PA

  20. #60
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    Va is a calculation requirement of Part 23 airframe certification.

    48. What is the design maneuvering speed VA?

    a. The design maneuvering speed is a value chosen by the applicant. It may not be less than Vsn and need not be greater than Vc, but it could be greater if the applicant chose the higher value. The loads resulting from full control surface deflections at VA are used to design the empennage and ailerons in part 23, §§ 23.423, 23.441, and 23.455.

    b.
    VA should not be interpreted as a speed that would permit the pilot unrestricted flight-control movement without exceeding airplane structural limits, nor should it be interpreted as a gust penetration speed. Only if VA = Vs n will the airplane stall in a nose-up pitching maneuver at, or near, limit load factor. For airplanes whereVA>VSn, the pilot would have to check the maneuver; otherwise the airplane would exceed the limit load factor.

    c. Amendment 23-45 added the operating maneuvering speed, VO, in § 23.1507.VO is established not greater than VSn, and it is a speed where the airplane will stall in a nose-up pitching maneuver before exceeding the airplane structural limits.
    Source- http://www.faa.gov/documentLibrary/m.../AC_23-19A.pdf

  21. #61
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    More interesting reading about Vb, design speed for maximum gust intensity. Look at paragraph d.

    http://www.gpo.gov/fdsys/pkg/CFR-200...-sec23-341.pdf

  22. #62
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    Not learned, but I consider that the MAX speed in turbulence, with SLOWER then that, all the way down to stall speed, even better/easier on the airframe. All I know is the more scared I get, the slower I fly, short of stalling it.

  23. #63

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    It might be different in jets at high altitude. You probably want to be equally away from stall buffet and high speed buffet, and often those speeds can be very close together. The buffet can be quite similar. Many jet jocks want to fly as high as possible, and sometimes that is just not a good idea.

    Henry Ginter was the Boeing instructor for jet aircraft performance. He said the B-47 could get so high that it would buffet no matter what you did, and the throttles could be moved with no effect on thrust. Coffin corner?

  24. #64
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    Bob, The limitation did not have an altitude associated with it. Not related to the coffin corner.
    N1PA

  25. #65

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    Cubs don't have a coffin corner - but I think Va is independent of altitude. I was just submitting a thought that might say turbulence penetration is best done at speeds somewhat removed from stall.

  26. #66

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    Quote Originally Posted by skywagon8a View Post
    This is a well written article. It brings to mind a question which I have asked several times and not received a learned answer. During my career, I have attended many ground schools for high performance aircraft. All of the airplanes have a list of limitations which must be memorized. One of which is: "Turbulence Penetration Speed M .xxx/xxx KIAS". My questions have been, "Are you supposed to fly at the Turbulence Penetration Speed or below it?". And, "If you are at a lower speed when penetrating turbulence, should you increase speed to the published speed?" The article seems to imply that you should be "AT" the turbulence penetration speed. I was never given an absolute answer. I was usually given a blank stare with a non answer. As a result the number was memorized and we moved on. I just flew carefully and didn't break anything.

    So, what say all you learned pilots, are we supposed to fly at that speed or below it when entering turbulence? Do any of you know for sure? Or, are you just speculating based on your training as described in the article? After more than 50 years, I still do not know.
    Glass cockpits and airspeed tapes give you a pretty good view of what you need to do. TPS is very close to L/D at high altitude and that puts you pretty close to the low speed hook. The higher you get you notice high speed hook closes in and thus the margin become narrow. So the answer is be on TPS. Equally so, in many cases where the turbulence loads the aircraft, you will note the increase in the low speed hook often up to L/D. Not a lot to play with there so being on TPS is important.

  27. #67
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    Quote Originally Posted by courierguy View Post
    Not learned, but I consider that the MAX speed in turbulence, with SLOWER then that, all the way down to stall speed, even better/easier on the airframe. All I know is the more scared I get, the slower I fly, short of stalling it.
    On the other side of that idea, I can remember a flight in my 180 where I decided my less than gross Va was 115mph. Straight and level I had frequent stall horn squeaks and occasional momentary stalls. At 60mph above stall speed. What then? Should a guy slow it down and increase the stall events and duration and reduce control authority? There's a balance of protecting the airframe and maintaining control. The more uncomfortable I get, the closer to max Va I fly. Personally I prefer to avoid those situations but sometimes you encounter unusual conditions along the way. Something to consider in all this over gross talk.

    One of the fun things about owning a 180 and a -12 was comparing them in rough air. A few times I'd fly one home and experience turbulent conditions, would land, and would quickly launch back out in the other plane to compare them. What a guy is comfortable with in the wind is a very interesting topic. Which plane and at what weight was fun to experiment with. Sometimes light and nimble is better. Sometimes it is not. Wing loading, power loading, and center of gravity. The holy trinity of aviation.
    Last edited by stewartb; 09-03-2014 at 09:48 AM.

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