Announcement

Collapse
No announcement yet.

"Engine Problems" Solved !

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • "Engine Problems" Solved !

    BTW, I have identified the cause of most of my engine failure on takeoff events, thanks to another event today.

    The bottom of the T-craft tank is slanted SLIGHTLY downward, so the fuel gravity feeds to the front, where the outlet is.

    One day a few months ago, taxiing uphill to the departure end of the runway with very little fuel on board, the engine quit. I put more gas in, and flew home with no problems.

    A few days after returning from a trip 3 weeks ago, I had a few gallons of car gas left in the airplane, and went out to fly and burn it off. I must have taxied onto the runway, turned the airplane onto the runway heading, and accelerated all in one fast move, the engine quit on takeoff. But I managed to keep it running, taxied off the runway, did three or four runups with no problem, and then took off again with no problems. I blamed it on the car gas, thinking something in the gas had swelled up the rubber tip carb needle.

    Last week I installed 8.00 x 6 tires to get a higher deck angle on the ground (looks cool too!). I did not think about the fact that it made the slope of the bottom of the tank LESS steep relative to the horizon. Today I took off with about 6 gallons on board, and swung out onto the runway, turned to line up with the runway, and took off in one smooth fast motion. Guess what?!? It stuttered and quit on takeoff again. We taxied off the runway, did three or four runups, found nothing wrong with it, and taxied back to take off again. No problems on takeoff the second time because I was careful to line it up on the runway before accelerating.

    It therefore appears the T-craft is very sensitive to un-porting the fuel outlet at the bottom of the tank when you have less than 4 gallons on board with 6.00 size tires, and even with 6 gallons on board if using 8.00 size tires. So please be aware of this very real problem if you are operating with minimal fuel in the airplane. I'm sure you would never have this issue if you always took off with 8 or 10 gallons on board, but there is supposed to be NO un-usable fuel in a T-craft so it is reasonable to assume you can take off with 45 minutes or an hour's fuel on board and not have a safety issue.

    The only other "real" engine failure I had was one flight attempt with another carburetor altogether, which was genuinely malfunctioning and has been replaced.
    Taylorcraft : Making Better Aviators for 75 Years... and Counting

    Bill Berle
    TF#693

    http://www.ezflaphandle.com
    http://www.grantstar.net
    N26451 (1940 BL(C)-65) 1988-90
    N47DN (Auster Autocrat) 1992-93
    N96121 (1946 BC-12D-85) 1998-99
    N29544 (1940 BL(C)-85) 2005-08

  • #2
    Re: "Engine Problems" Solved !

    On our runway, the north end is uphill farly steep. I used what portion for a takeoff last week. We have no wind and I din't wanted to wast runway length. I did a runup in this nose high position as well. No problem with 6 gallon in the tank.
    Bill do you have finger strainer in the tank,it could be partly plugged?
    A friend of mine used to own a homebuilt ,(a Fike also a drager) and it hade a slosh coated tank and some of the sloshing material was loose in the tank and would cover the outlet,SOMETIME
    HIS ENGINE WOULD BEHAVE SIMMILAR TO YOURS.
    You make a fast Turn onto the runway the fuel should not move away from the outlet to a degree what the engine dies or sputter, after all I can run full power for 15 to 20 seconds maybe more with full trothel and fuel shut off. ( A 65) Just on what fuel is in the carb. I say you have a "dirty" tank!
    Note what sloching componds will NOT accept a change from Avgas to Mogas They are made of different compounds for the different fuels, see Aircraft Spruce catalog, they sell 2 different kind, selection is depending on the type off fuel used!
    Len
    Last edited by Len Petterson; 10-28-2008, 04:06.
    I loved airplane seens I was a kid.
    The T- craft # 1 aircraft for me.
    Foundation Member # 712

    Comment


    • #3
      Re: "Engine Problems" Solved !

      in my 1982 f21 it shows 3.0 gal unuseable in the main 12 gal tank per the POH.

      Comment


      • #4
        Re: "Engine Problems" Solved !

        Sounds reasonable Bill...glad you figured it out!! We're running 8.50's here too, so will have to keep that one in mind... just gotta line up and behave for a few seconds....or carry a mostly full nose tank.
        Thanks!
        John
        I'm so far behind, I think I'm ahead

        Comment


        • #5
          Re: "Engine Problems" Solved !

          ALSO ! Those of us with 85 or better horsepower... I am guessing that a higher powered T-craft can get to a fairly high "deck angle" on a max angle takeoff to clear an obstacle. This would potentially cause the same problem, except that it could happen after takeoff and over those big trees you are trying to vault over.

          The best possible solution IMHO (suggested by a friend) is to have another outlet at the back of the tank that is connected to the main (front) outlet. That way the fuel would get to the gascolator from either outlet regardless of the deck angle.

          This of course would be a modification which would be much easier to do with the tank out of the airplane during major maintenance.
          Taylorcraft : Making Better Aviators for 75 Years... and Counting

          Bill Berle
          TF#693

          http://www.ezflaphandle.com
          http://www.grantstar.net
          N26451 (1940 BL(C)-65) 1988-90
          N47DN (Auster Autocrat) 1992-93
          N96121 (1946 BC-12D-85) 1998-99
          N29544 (1940 BL(C)-85) 2005-08

          Comment


          • #6
            Re: "Engine Problems" Solved !

            I can see it at 3 gallons (maybe) but Six? Just trying to contribute something helpfull here, not be disagreeable. As you know I have pretty much the same setup as yours Bill, but I have never had that happen and I have 8.00 tires and do pattern work, starting with 4 or 5 gallons in the main tank, all the time.
            I humbly suggest there may be another problem and it is corrected by having the additional pressure head when you have more gas in the tank.
            I am thinking things like a sticking needle valve or float. Binds on the first takeoff of the day, for example.
            Doesn't sound like garbage in the lines or tank, although when I took my shutoff valve off and drained the tank I couldn't believe the debris in the bottom of the tank. Scary.
            Darryl

            Comment


            • #7
              Re: "Engine Problems" Solved !

              Originally posted by flyguy View Post
              I humbly suggest there may be another problem and it is corrected by having the additional pressure head when you have more gas in the tank.
              I am thinking things like a sticking needle valve or float. Binds on the first takeoff of the day, for example.
              We had the carburetor off, and checked it thoroughly for function, set the float level, etc. not 25 hours ago. I would assume that if the float was going to bind up it would bind up when I ran it up to check the mags ??
              Taylorcraft : Making Better Aviators for 75 Years... and Counting

              Bill Berle
              TF#693

              http://www.ezflaphandle.com
              http://www.grantstar.net
              N26451 (1940 BL(C)-65) 1988-90
              N47DN (Auster Autocrat) 1992-93
              N96121 (1946 BC-12D-85) 1998-99
              N29544 (1940 BL(C)-85) 2005-08

              Comment


              • #8
                Re: "Engine Problems" Solved !

                You can run quite a while on one carb full of gas. Supposedly that was what happend to a guy flying a BC12-65 that I had sold. He made it to about 200 feet and unfortunately tried to turn back. Mind you I never believed that was so just because they found the fuel cutoff pulled. I didn't think he could get that far at full throttle and just pulled it for safety after the engine shut down for some other reason.

                As you say, not likely the carb since you have had it gone through. I really love intermitten failures--they will drive you totally nuts.

                I never got around to trying to duplicate your failure, as I have been having quite enough problems with my funky magneto.
                DC
                PS: I try to remember that things often fail just after being worked on, (infant mortality, incorrect parts, assembly errrors, all that.)
                Last edited by flyguy; 10-28-2008, 15:01.

                Comment


                • #9
                  Re: "Engine Problems" Solved !

                  I was "noodling" on this all day...and I just happen to have a BC12 with 8.50's sitting here with no bootcowl... so I grabbed a level and set it under the tank tonight. The rear of the tank is a bit higher, but not that much. (the level is sitting level in the pics... sorry for the optical illusion) I do have to think that you'd have a bit of time to empty the float bowl of the carb, as well as the lines and gascolator, but this is sure something worth noting... I've seen stranger things happen. Just for reference... the front of the tank is 1.5 inches lower than the rear of the tank in 3 point attitude as measured with the 8.50's.
                  John




                  Last edited by N96337; 10-28-2008, 18:42. Reason: changed pic to a better one
                  I'm so far behind, I think I'm ahead

                  Comment


                  • #10
                    Re: "Engine Problems" Solved !

                    Would a larger diameter tail wheel solve the problem?
                    Don

                    Comment


                    • #11
                      Re: "Engine Problems" Solved !

                      I guess the thing that bothers my sense of logic (lean as it is) is how long would the tank drain be uncovered, that is, tail down and accelerating? Maybe 5 seconds? Surely the carb bowl and line would keep the engine running that long even at WOT. It seems like forever to run mine out of fuel at 1500 RPM for shutdown. Bet it is 45 seconds at least.
                      It is really quiet at this airport during the week, maybe I will play around with 3 gallons in the main. (don't worry, we have 4,000 ft with overruns. I'll keep it on the ground.)
                      Darryl

                      Comment


                      • #12
                        Re: "Engine Problems" Solved !

                        I am willing to bet the deck angle and low fuel on board has nothing to do with why it quits on the ground. See how long it will run when you pull the main fuel valve to off. There should be enough fuel in the bowl to run at idle for about 30 seconds or more. I never had any fuel starvation problems even which only 2-3 gallons of fuel on board and 26" bushwheels. On every Taylorcraft I have worked on I could drain all the fuel from the main tank out through the gaskolator with the plane sitting 3 point. Remember that the gaskolator needs to be mounted so it's the lowest point in the fuel system.
                        Jason

                        Former BC12D & F19 owner
                        TF#689
                        TOC

                        Comment


                        • #13
                          Re: "Engine Problems" Solved !

                          I am willing to bet the deck angle and low fuel on board has nothing to do with why it quits on the ground. See how long it will run when you pull the main fuel valve to off. There should be enough fuel in the bowl to run at idle for about 30 seconds or more. I never had any fuel starvation problems even with only 2-3 gallons of fuel on board and 26" bushwheels. On every Taylorcraft I have worked on I could drain all the fuel from the main tank out through the gaskolator with the plane sitting 3 point. Remember that the gaskolator needs to be mounted so it's the lowest point in the fuel system.
                          Jason

                          Former BC12D & F19 owner
                          TF#689
                          TOC

                          Comment


                          • #14
                            Re: "Engine Problems" Solved !

                            So guys... tell me what would cause this problem OTHER than un-porting the tank outlet? This exact thing has happened twice now, and both times I did the following:

                            Taxied off the runway running at idle
                            Did two or three full throttle runups within 30-45 seconds after it stuttered
                            Found no problems with the runups
                            Taxied back, took off more carefully
                            Climbed out at a normal angle
                            Flew for 30-40 minutes with no problems at all
                            Taylorcraft : Making Better Aviators for 75 Years... and Counting

                            Bill Berle
                            TF#693

                            http://www.ezflaphandle.com
                            http://www.grantstar.net
                            N26451 (1940 BL(C)-65) 1988-90
                            N47DN (Auster Autocrat) 1992-93
                            N96121 (1946 BC-12D-85) 1998-99
                            N29544 (1940 BL(C)-85) 2005-08

                            Comment


                            • #15
                              Re: "Engine Problems" Solved !

                              If you have one, post a side view picture of your firewall forward with the cowl removed that shows the relative position of the gaskolator and fuel line to the carburetor. I would also like to see a picture of your main fuel valve setup

                              I suspect a carb problem, but am not ruling out a supply issue. It might even be ignition switch or p-lead related????
                              Jason

                              Former BC12D & F19 owner
                              TF#689
                              TOC

                              Comment

                              Working...
                              X