Piper Cherokee 140 nose cowling crack

Discussion in 'Maintenance Bay' started by jason gula, Jan 31, 2020.

  1. jason gula

    jason gula Pre-Flight

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    I’m writing here as I’m a new owner to a 1969 Piper Cherokee 140. Upon a recent inspection to the nose cowling, below the propeller and off to the side, I’ve observed some sort of circular gouge in the cowling, maybe an inch or two long. The cowling is secured and not loose and we’ve been flying the plane with no issues. Prior to the purchase the plane had an annual with no issues. I’ve also separately had a prebuy inspection from a different a&p who found no issues. I’m curious, if this is an inspection issue or merely cosmetic as it is not affecting anything. I can provide a photo over the weekend if needed.
     
  2. Grum.Man

    Grum.Man En-Route

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    has it always been there or happened between flights?
     
  3. jason gula

    jason gula Pre-Flight

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    I just bought the aircraft in December and I noticed it then. Again, it was inspected by two separate a&p’s who haven’t mentioned it. After flying it for approximately 10 hours, it is still the same and not getting any worse or changing. Last thing I want to do is ask a shop if it’s okay. I’m sure they will give me the answer “oh we need to take care of that”.
     
  4. Grum.Man

    Grum.Man En-Route

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    I wouldn’t be concerned. What likely happened is someone ran it without the tip cowling on and the nose bowl flopped around and got into the spinner.
     
  5. jason gula

    jason gula Pre-Flight

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    That makes sense. It’s circular around the bottom side of the propeller.
     
  6. kgruber

    kgruber En-Route

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    Do you have a picture?
     
  7. jason gula

    jason gula Pre-Flight

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    I'll try to grab one this weekend and post it. I have a pic of the front of the aircraft, but you wont be able to notice it.
     
  8. murphey

    murphey Final Approach PoA Supporter

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    Depending on the condition, you may be able to do the fiberglass repair yourself with approval by the A&P. For non-structural parts, like the tailcone, the owner can repair minor fiberglass problem without A&P signoff. I recommend the fiberglass blanket kit you can find at your local Aviation NAPA shop. Piper maintenance manual has detailed instructions how to do fiberglass repair, by the way. I speak from experience. Do a good job and you won't even need touch-up paint.

    In the 2009 Warrior MX manual, fiberglass repairs are in Section 4 - Structures, 4-57, Grid 1F20. The instructions read a lot more complicated than it really is.
     
    Last edited: Jan 31, 2020
  9. jason gula

    jason gula Pre-Flight

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    Thanks. I'll look into it but I don't want to make more of a mess out of it, then I have to get it repaired. The owner said it's been there for a while now. Either, it's not a big deal as it's not structural or a hazard, or two A&P's overlooked it during the pre-buy process.
     
  10. murphey

    murphey Final Approach PoA Supporter

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    Patching simple cracks in fiberglass:

    1) understand you're working on the underside, the inside of the cowl.
    2) clean it really good. I used comet cleanser - it's a mild abrasive altho the instructions say degreaser, etc.
    3) buy a small fiberglass patch kit
    4) cut the fiberglass blanket to the appropriate size to completely cover the area in question
    5) put on nitrile gloves
    6) you really want to do all this when it's at least 50F
    6a) mix the epoxy - instructions in the kit
    7) lay the fiberglass and the epoxy. It's pretty much like patching sheetrock but you don't have to sand and paint after.
    8) when finished, the epoxy is no longer any good, so wrap it carefully and dispose properly
    9) go home to let the epoxy dry
    10) come back tomorrow and fly
     
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  11. jason gula

    jason gula Pre-Flight

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    Heres a photo of the front of the aircraft. If you zoom in, you may be able to notice it under the prop. If not, I'll grab a photo this weekend.

    upload_2020-1-31_22-1-28.png
     
  12. jason gula

    jason gula Pre-Flight

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    Thanks. Curious, does this stuff come in different colors? I'll have to blend it into the red cowling unfortunately.
     
  13. jason gula

    jason gula Pre-Flight

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    The simple "boat fiberglass" kit on aircraft spruce work for this?
     
  14. murphey

    murphey Final Approach PoA Supporter

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    You're working on the inside of the cowling, not where it's painted red. Inside. Where all the crud is.
     
  15. murphey

    murphey Final Approach PoA Supporter

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    Why not? It's just that NAPA is closer to me than West Marine.
     
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  16. jason gula

    jason gula Pre-Flight

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    Got it. So a regular fiberglass repair kit fro NAPA will work? My only concern is the location, where the repair will be subject to 120mph air blowing on it/through it.
     
  17. murphey

    murphey Final Approach PoA Supporter

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    Then chat with the A&P and ask if it's a real problem or just cosmetic.
     
  18. Pilot Steve

    Pilot Steve Pre-Flight

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    If you are worried about it spreading while you sort it out, a strip of Gorilla clear tape over it works like a charm to help protect it in the meantime.
     
  19. jason gula

    jason gula Pre-Flight

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    I may try this as a cheap alternative. The previous owner stated it has been there for a bit now and passed inspections. I'm hoping when I bring it to my IA he has the same thoughts.
     
  20. Dan Thomas

    Dan Thomas Final Approach

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    Those kits usually have polyster resin in them. You want epoxy. Epoxy sticks ten times better than the polyester. The cowl was made with polyester resin, but new poly resin doesn't stick all that well to old resin.
     
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  21. jason gula

    jason gula Pre-Flight

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    Got it. So the epoxy is strong enough to stick on the nose cowling, even with the airspeeds?
     
  22. murphey

    murphey Final Approach PoA Supporter

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    One more time....the repairs are on the INSIDE of the cowl. No one will see the repairs unless the cowl is removed. Inside, where it’s not painted red. Inside where it’s really cruddy from all the engine crap. Inside where the 120 mph wind is not hitting it.

    When you’re inside your car, windows rolled up and driving 75 mph, does the wind affect anything INSIDE the car? Nope. At least I hope not.
     
  23. Dan Thomas

    Dan Thomas Final Approach

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    I have repaired fiberglass cowls and other parts with epoxy and it stays there no matter the speed. Even on the outside. The preparation is important: paint and all oil or grease must be removed. The epoxy can't stick to the cowl if there's any contaminaion in the way. I've repaired sloppy repair jobs where almost no prep was done, and the patch was falling off. It's more work the second time, since it sticks in a few places and has to be carefully ground off.
     
  24. Domenick

    Domenick Pre-takeoff checklist

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    Actually, exterior airflow does create force on the exterior sheathing. You don't feel it, but the sheathing will flex and vibrate. The question is will the repaired cowling resist the flexing and vibration induced by airflow and engine?
     
  25. murphey

    murphey Final Approach PoA Supporter

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    But you don’t have to paint it red. Even if the shop repairs the crack, it’ll use the procedures in the Piper manual.
     
  26. jason gula

    jason gula Pre-Flight

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    I'm going to grab a picture and send it. It's more of a gouge than a crack, being able to see through the cowl where the damage is located. So, even working on the inside of the cowl, the patch will be able to be seen on the outside as the gap is filled in. Which is why i asked if that is strong enough to withstand the air speeds. I'd rather not have a failed patch blowing around the inside of my engine compartment.
     
  27. Dan Thomas

    Dan Thomas Final Approach

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    It will need fixing on BOTH sides. Best to leave it to someone with experience in this. You need more than a repair kit; you need an angle die grinder with appropriate discs to clean up the area and dress the repair, and a mask to keep the dust out of your lungs. Eye protection, too. You need to know how to orient the fabric weave to make it conform to compound curves. You need to know how to properly layer the glass. You need to know not to use too much resin.

    AC43.13-1B has a chapter on it.
     
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  28. Ravioli

    Ravioli Final Approach

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    I think your first step is to mark both ends so you can see if it's growing.

    IRAN -- Inspect Repair As Necessary should suffice on this.
     
  29. murphey

    murphey Final Approach PoA Supporter

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    aHA! Didn’t understand that it’s all the way thru and not a simple crack. Yup, this is for people experienced in this stuff, not beginners.
     
  30. kyleb

    kyleb En-Route PoA Supporter

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    Me? I'd put a layer of electrical tape on the outside to keep the epoxy trapped on the inside. And I'd make an interior repair using fiberglass cloth and epoxy resin, after carefully cleaning and sanding the interior. That'll keep it from growing. Once the epoxy hardens, remove the electrical tape.

    It'll look the same as it does now from the outside, but won't leak air and the crack won't grow. Of course, this repair probably requires prop removal, so you'll need to get an A&P involved for that part.

    The next time you have any touch up paintwork done, have them do the cosmetic part on the outside.
     
  31. mondtster

    mondtster En-Route

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    I’ve made a lot of simple repairs using this method as well. It is somewhat crude and probably not as good as other repair methods but it works and holds up fine. As suggested by Dan earlier in the thread, I’d use epoxy resin, not the cheap stuff you’ll get at the hardware store though.

    Here’s a good link to a more involved repair that would probably be a better method than the tape and fill method Kyle proposed and I’ve also used.

     
  32. jason gula

    jason gula Pre-Flight

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    Again, as I'm new to this.....this the cowling under the prop easily come off, with screws? Or something more advanced?
     
  33. mondtster

    mondtster En-Route

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    Depending on when it was built, some are split and some require prop removal. Judging by the picture you posted, your nosebowl will require removing and reinstalling the prop, which requires help from a mechanic. Either way, being a new owner with minimal experience maintaining airplanes I’d strongly suggest finding an aircraft mechanic who is willing to supervise and show you the ropes of aircraft ownership/maintenance. A Cherokee is simple machine but there are rules and guidelines for how things need to be done.
     
  34. murphey

    murphey Final Approach PoA Supporter

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    Hm....I've never seen a cherokee that needed the prop removed to take off either the bottom or top cowl. I should look more carefully at the cherokees out here at the field. I've seen the piano hinge top cowl to make it easier to check/add oil (and I'm incredibly jealous considering I have to remove the entire top cowl to install the oil cooler cover).
     
  35. kyleb

    kyleb En-Route PoA Supporter

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    We're not talking removing the cowling, we're talking removing the nose bowl. I've never paid much attention to Cherokees either, but I think (thought?) they have a one piece nosebowl. If it is a two piece, then the owner should be able to remove it fairly easily. Otherwise...
     
  36. mondtster

    mondtster En-Route

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    I’ve never seen a split nosebowl in the style shown in the picture here either but that doesn’t mean it isn’t modified. Plus, the later 140s had a different bowl that was two piece.

    I’d say the odds are really high that the prop is going to need to come off so the nosebowl can be removed in order to make a repair that I’d consider adequate.
     
  37. Domenick

    Domenick Pre-takeoff checklist

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    Depending on the -140 year and serial number it either has a split or unsplit nosebowl. Either the prop has to come off or not. If the prop needs to comes off the owner can pull it, but not replace it. If you do decide to pull the prop, consult with an A&P BEFORE removal.
     
  38. Timbeck2

    Timbeck2 Final Approach

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    I have a 69/70 Cherokee as well - the prop has to come off. Not a big deal. You have the rest of the answers you seek.

    I had a similar problem with the starter ring rubbing on the inside of the nose bowl to the point of coming through. I repaired it with fiberglass and epoxy and repainted the entire nose bowl. I'm now very careful when I replace the cowling and make sure it is tightened in such a way that the nose bowl clears the starter ring.
     
  39. jason gula

    jason gula Pre-Flight

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    Here is the photo I took today. Is this a major problem or something cosmetic that can be repaired down the road.....

    upload_2020-2-3_18-51-59.png
     
  40. murphey

    murphey Final Approach PoA Supporter

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    That little thang? Put a strip of 100 mph tape over it and go fly.
     
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