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  • #61
    LETOV SLUKA

    OK Bill, well at least we would like to contribute to the bottle !......I'm for Edinburgh mid July to continue my family tree research, but I know you are quite a distance away, up in Wick. OK on X air thermometer.
    OK Gerry, The carb heater was fitted by the builder, not me. It is a heating element inserted into the carb body, and draws 5amps from the ac generator. Dont know how warm it gets as I haven't quickly got out and touched the carb after a flight. I must try that Bill.

    Unfortunately I have a developed a worry since my permit renewal. I was away flying today in her. Left at 10:15am for 1hr 5 minutes, and landed behind a farming relative's house. No probs. After over an hours' stay took off again with no probs and flew back to the strip. Another 1hrs flight. Just after anouncing that I was on base leg for the strip and with the power well off to loose height, the engine just died. I couldnt believe it, I was stunned. Anyway in put her down safely in a field between a lot of HT pylons, as our strip is near a power sub station. My first power failure, she glides perfectly. I was still amazed when i landed. Couldn't get her started straight away as I had flooded the carb and had to wait a while. But she started again and i took off and landed on the strip with no further probs. Now this is what happened to the examiner when she was going through her flight test for the permit, and everybody put it down to carb icing. But now I dont know about that. Trying to think what was happening at both times, all thats common was the power was back and the plane was turning onto finals. It looks like a fuel problem. But the filter was full of fuel when I landed in the field, so i am assuming it is something between the filter and cylinder, Maybe the pump. Have ordered the repair kit for the pump. I did renew all the fuel hoses from filter to engine, but inspector was happy with them. Any ideas Bill?

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    • #62
      LETOV SLUKA

      I'll put in another rambling instead of making the last any longer !... Yes Bill I did see the mention of the fatality in a sluka last August. I presume there are no details as it is still under investigation. Terrible that, as he was coming in to land ! very strange he had control problems, then dived. maybe it was one of the tail bracing wire tangs. My inspector remembers replacing the ones on my machine with stanless steel ones rather than the weak aluminium, But Yes a good idea to have them separated.

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      • #63
        LETOV SLUKA

        Victor, Here is the drift of what happened to me. I had just bought the Sluka and went for my first take off at Wick. I took off normally and was on left turn out when the engine stopped completely at about 300ft. I landed ok on a peritrack. The engine would not restart hot, but started after about twenty minutes. I plucked up courage and went down to the end of the runway and took off again to see if the problem reappeared. The engine behaved normally over the circuit. Next time I took off it stopped again, so grounded myself until the problem was solved. I did continuity checks on the ignition coil and insulation was ok.
        Then I checked out the fuel system and found nothing untoward.
        I don't know what prompted me to do it, but it was the requirement to check the ignition generator coil regularly that pointed me in that direction.
        I carried out a full power ground run and sure enough the engine stopped when everything warmed up. I removed the flywheel and took the coil into the instrument department at Rolls Royce and told them to do continuity checks at increasing temperatures. Initially they found no snags, until the guy held the leads coming out of the mouldings at each end with the multimeter connected, and when he moved the wires it went open circuit as if there was a switch on it - a defect on the wiring within the moulding. I got a new coil from Skydrive, fitted it and took the opportunity to renew the points as well, put the engine back on and away it went with no further frights. I had thought of wearing a stout pair of brown corduroy trousers for the test!!
        It can be a real pain trying to find an intermittent fault. That is why I had to pluck up courage to find the fault in flight conditions It was flat calm and I knew I had plenty of room to land safely.
        Remember, if you have air, spark and fuel, everything should be ok.
        Regarding the fatality, if you phone the engineering department at the PFA to enquire if there is a preliminary report on the accident, they may give you a hint of what happened.

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        • #64
          LETOV SLUKA

          I'm tempted to say at this stage, Bill, "Its nice to hear that I'm not the only one that this happens to", so the problem has a chance of being sorted, (many heads and all that) but as we are talking about engine failures, I'll refrain from saying it. But I am glad I posted it here.

          Just looking back over my logs, dring the year I have flown it, the average flight time is approx 2hrs (6 over 2hrs, 13 > 1hr and 5 < 1hr) up to the permit, and since then 1 > 2hrs, 3 > 1hr and 6< 1hr. Dont know if this could still point to the ignition coil area. Would the engine have stopped on all or most of these flights. What do u think? How long was the ground test ? 10mins or are we talking about near 30mins? was it at as high a rev count as possible using the brake, or did you chock the wheels to get more revs? or even tie her down !

          I just keep thinking there was something done for the permit to cause this problem. What about cheap fuel ? Although when then engine did fail I thought it was no spark. I thought if it was fuel starvation it would maybe splutter ajnd not just die quietly. Come to think of it when in the field it did take a long time to start again, and i put this down to flooding the carb. Thinking back to the tets flight with the instructor, it would have been 10-15mins maybe before we tried it again (After he was asking me all the questions as to what was done to the engine for the permit). So can the ignition coil fault just develop over time, and not be present from birth? Better end this now I'm rambling.

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          • #65
            LETOV SLUKA

            Victor,
            The ground test took less than five minutes. The Sluka was ckocked and two volunteers held on to the main wheel "legs". The engine did not splutter nor did I get a reduction in revs - it just cut out as if I have just put the ignition switch to off. Revs were at 6000.
            How was the head temperature. If high, this can indicate late timing. How old was the fuel in the tank. Fuel loses a fair bit of volatility with time. I change mine if it has been unused for about a month.
            Maybe engine vibration can cause the coil to fail, but mine was a definitive wiring failure.
            I also had the engine stop on final (post coil renewal) and put this down to engine timing and a defect in the ceramic part of those platinum spark plugs. This was identified by a burn mark on the plug hexagon just below the defect - so the spark was jumping to earth.
            Is the rubber hose between the carb and engine intact.
            Skydrive also said that sometimes a little bit of rubber fuel hose can get lodged in the carb - just where it enters the casting. Don't worry we will work it all out somehow.

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            • #66
              LETOV SLUKA

              Oh dear..if I had your post before i ran my engine I could have saved a lot of fuel !!.....I have just run the engine for 1 hr. Mostly at 4500 - 5000 rpm, with a short time at 5500. But I couldnt get it to stop, when I backed off the revs. So dont now think it is the same prob u had with the coil. Will go for an 1hr or so flying tomorrow morning...oh i see its friday the 13th hmmmmm. CHT is a bit uneven on each side. The max i could get today on the ground was nearly 400degrees on one side with the other around the 350 or less. Same with EGT a bit of a difference but not the same degree of difference. Fuel is OK. I just mentioned it last time as i had been using petrol from one of these cut-price garages. Used it the last couple of times. But today used the full-priced stuff. Didnt look at plugs, will do that tomorrow. They had done around 30hrs or so. Yes I have ordered a new carb socket to renew that bit. and also ordered the repair kit for the fuel pump. Yes OK on bit of hose in carb input. Well the inspector thought it could be something like that, and we took the bowl off and the float out and blew back through the inlet port. He wanted to use compressed air but none available. Could it be something stuck in there. then? I did cut the new hoses with a hawsaw, (To his horror!!) but blew etc through them, but he would have liked liquid through then before i fitted them . any clue there Bill?

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              • #67
                LETOV SLUKA

                Victor,
                I,ve just remembered another important check to do. I had also found quite a bit of backlash in the main jet clip retaining groove. If it is worn the needle can drop down just that little bit and give you a reduction in revs with attendant leaning of mixture which will also increase CHT.
                I think I would flush through your fuel lines to make absolutely sure there is no rubber debris hanging about. The thing is it can sit there and possibly give spurious blockages.

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                • #68
                  LETOV SLUKA

                  OK Bill I'll check those areas and flush the tubes. Let you know what I find.

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                  • #69
                    LETOV SLUKA

                    Bill, Victor Hi!
                    As you know I'm new to the Sluka and the 447 so be gentle. If the spark is points driven then it has a condenser as well as coil? Could the condenser have a intermittent problem? I was also intrigued at the calmness of the no engine event! I'm sure it wasn't that relaxed but does the sluka glide reasonably and with good control?
                    Regards
                    Gerry

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                    • #70
                      LETOV SLUKA

                      Yes the ignition system has a condenser for each set of points. Points gap setting and the need to remove the engine from the boom to get enough room to do this is steering me towards getting an electronic version of the 447 or even the dual ignition 503, which apparently, someone has fitted. Engine removal however is very simple and takes no more than fifteen minutes - needs two people to do it. I make sure there is a chair or something under the tailskid tube and then remove the engine/propeller assembly to a clear workbench. I find trying to set the points through the flywheel "windows" a bit tricky, therefore remove the flywheel to do this - you need the flywheel removal tool which I got through Skydrive - very simple to use.
                      You won't find a more docile 3-axis than a Sluka. You don't need pedal input when flying, just point it the direction you want and it will do as asked. The take off acceleration never ceases to amaze me - it takes off like a rocket.
                      I have an intake silencer on mine and am told that it is extremely quiet when flying overhead. I find that on a clear frosty winters day it is a job to get it to descend - you virtually have to force it to land. I firmly believe that if there is a fuel/air/ignition problem that it will show itself during the take off phase when everything is churning away, flat out. I have quite a long taxiway, therefore the engine is nicely warmed up before takeoff. The only problem I can see in established flight is perhaps carb icing if you haven't got a heater.

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                      • #71
                        LETOV SLUKA

                        Hi Bill/Gerry. Yip I surprised myself when she cut out. But it glides so well. There was no panic to push the stick forward. I didnt look at any instrument after the cut out. After I was certain the prop had stopped and was not to turn fast enough to give me control. (it did turn jerkily for a very short time as the wind pushed it) I just spent the time from 800ft picking the field and setting it up for a gently landing. I know they say you shouldnt do a sharp turn but the filed i wanted was passing on my left so i had to turn nearly 180degrees. Which was were my 800ft went. !! It was an uphill slope, couldnt have asked for a better field. OK bill on the points. Well I dont know if I have points or not !! What signs or components on the outside of the casing would tell you?....I am now thinking it could be a fuel prob. What about the priming bulb. i dont know its history, but it looks shiny enough with no cracks anywhere. But i hear there is a component inside which may move and inter block the pipe. I read this re-guarding a flex-wing prob. I had her up for 1hr today, from 9 - 10am. I was worried about all the air bubbles that were going up the pipe in front of me. Surely there shouldnt be ANY at any time eh? I have noticed these before, but only a couple of small ones and always after hitting a bit of turbulence. But todays was the worse i have seen them, which one of the reasons for only 1hr flight. They were coming all the time even when flying calm. And I was thinking on both times she failed it was turning left for finals, so maybe the internal component moved in the priming bulb and blocked pipe. I cant remember what bubbles if any where in front of me then, I was looking out, lining it up on the runway. So I've ordered a new one of these. A modified one from PMA. BTW I checked the plugs and all seem OK.

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                        • #72
                          LETOV SLUKA

                          The primer bulb is fitted with a one way valve, there was a few faulty ones around a couple of years ago. Once you are primed though, there should not be any bubbles going along the fuel lines. It suggests that the system is sucking in air at some point. The favourite for this is one of the joins clipped with a Jubilee clip. If clip has been moved and the pipe is in anyway hardened it will not reseal well, if in doubt cut it back or replace the pipe. You can check by useing the bulb to pressurise the system and waggle the pipe near any joint to see if you can reproduce the bubbling, that will help to track it down. The other cause that springs to mind is that should the bubbles show in the pipe between the Mickuni pump and the carb you may need to service the Mickuni, this is dead easy and the service kit is available from Skydrive.
                          Also if you have wear on your carb neadles in the groove you should fit the tiny O ring to the neadle that you will also get from Skydrive. This just pushes down onto the top of the neadle and prevents the circlip from moving. it is a good idea to check if you have these fitted anyway just to prevent wear from taking place
                          Good Luck
                          Ginge

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                          • #73
                            LETOV SLUKA

                            Hi Ginge.

                            Yes I am replacing all the fuel lines from the tank to carb, some of them again. I am going to use the clear 6mm plastic pipe advertised by LAS as used for microlights on "some parts of the fuel system". Not sure what "certain parts" means. Surely if its suitable for some its suitable for all parts, No.?....OK on the hardening of the ends of the existing pipe. Well yes we took the tank out and drained it, to look for debris, none was found. So maybe the re-connection of the pipe there was not tight enough. OK on the fuel pump. Yip I've just got the repair kit for that & the carb socket to the engine. So i'll do those this afternoon. Just seen though, you can get a new carb from LAS for the price of the repair kit i got from skydrive !. I have also just found out the length of the vacumn pipe from crankcase to pump is specified in the engine build paperwork i have. Its 150mm I must check this as i just cut a suitable length of pipe for this and think it mihgt be a bit longer. Is this length critical do you think?.. Is the bore of this pipe different from the other fuel lines. Is it 4mm ?...Unfortuneatly the carb is not an area i like working on, as i dont really know what i'm doing there!!....

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                            • #74
                              LETOV SLUKA

                              Right Jeremy, I see now why its clear up to the filter and black rubber type after that. OK I'll stick to that. Just got the carb socket rubber fitted today. Maybe its just me but the carb did feel a lot "stiffer" on the engine, takes more force to move the assembly.

                              What is the orientation of the aerials on commercial jets? Using the hand held radio at home with its whip antenna. I get the local airports' information service better horizontally than veritically. Is it jus for convienence that all microlights use vertical, because i was thinking of mounting a half wave dipole under the cabin of the Sluka. In fact i'm going to try it out someday, by taping a thin wire dipole to the underside and comparing the standard vertical whip i have on the boom behind the wing. Have you any thoughts on this?

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                              • #75
                                LETOV SLUKA

                                OK Jeremy. Have read article.Very good.I have now food for thought. Many thanks.

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