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  • FUSELAGE CRACKS

    [3][/3]

    [3]Having recently removed the front wing saddle from the fuselage (G MZGF) I have discovered the dreaded cracks (3) that some of you may have already sorted. I am of course dealing with my LAA Inspector, however, the LAA are finding it difficult to refer me to someone who has had this Mod approved (their last correspondence referred me to a Cessna registration??) Can anyone kindly provide me with the details of an approved modification and/or refer me to where I might be able to source a Mod. Also the holes in both leading edge roots and front saddle (where the locating pins go through) need bushing. The saddle bushing looks straightforward, but I would be interested to talk to who may have tackled the leading edge wing root holes. Any info would be useful. Thank you.[/3]

  • #2
    FUSELAGE CRACKS

    Roger
    One Sluka that had the Main Boom Mod was G-MZOI owned by Brian Finch and based at the moment in Kemble.
    As I recall it was the official PFA(LAA) Mod and would have been done about 4 years ago.
    Brian might help if you e-mail him at bspfinch@googlemail.com
    If that fails then let me know and I'll talk to his Inspector who carried out the Mod.
    Regards
    Gerry

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    • #3
      FUSELAGE CRACKS

      Thanks Gerry, I have mailed him.

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      • #4
        FUSELAGE CRACKS

        I'm fairly sure that if you have cracks you have to renew the boom tube. Cracks are a no-no and will grow to failure.

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        • #5
          FUSELAGE CRACKS

          I seem to recall that there was a repair scheme that involved stop drilling and sleeving, but I can't recall the detail. I understand the fuse tubes are no longer available from Letov as they have been out of production for a while.

          Sorry I can't be of more help but I suppose that you could try to contact owner getting the contacts from GINFO as there are a fair number about, including our own chairman, Keith Negal

          Ginge

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          • #6
            FUSELAGE CRACKS

            I once ask Guy why round boom tubes were used in microlights. He replied that it was purely "habit" - I still have the letter. I think there is a strong case for using square section ones with radiused corners. It would be dead easy to convert the Sluka to square section - apart fron the engine mount system, but that could easily be changed to something like that fitted to the AX 3-axis micros (done already on one I hear). It would be a great pity to see the Sluka sink without trace over such a "minor" issue. It is a little belter. However, getting it through the mod approval process would kill it stone dead. The sleeving and stop drilling repair proposed by Sluka when the problem appeared was thown out by the LAA.

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            • #7
              FUSELAGE CRACKS

              The only microlight that I recall seeeing with a square section tube was the old Scout so I'd alway assumed that there was good reason. As a matter of interest is the tube the same dia as a Thruster? They are certainly similar, and I'm sure that Thruster would supply an undrilled tube is asked, they are a pretty helpful lot. Failing that they may be able to put you onto a supplier of such tubes, as you say a Sluka is too good an aircraft to let go of easily

              Ginge

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              • #8
                FUSELAGE CRACKS

                Very interesting (as always) to hear your views comments gents. My correspondance with LAA have resulted in me receiving drawings from them for a mod which has already been used on one Sluka. I have also spoken to an engineering company who have successfully mod'd G MZOX fuse tube (with a different mod procedure to same problem) and fitted a 503 to it. Ginge, I will measure my mates Thruster fuse today, could be simpler.
                I will let you know how I progress and once again thanks

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                • #9
                  FUSELAGE CRACKS

                  Hi Roger, the Shadow has a round boom tube which may be suitable as well. Danny Crosbie has stock and can be contacted on 07966 176080. Good luck - am looking forward to seeing the Sluka in the air again!

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                  • #10
                    FUSELAGE CRACKS

                    Roger, can you describe the mod for the engine mount ? And I am definitely keen to hear about that 503 on a Sluka as well. Should I need to change mine I would go for that option for the dual ignition alone. The tube bore is about 89mm with the OD about 92mm (ish). Another mod I would like to pursue on the Sluka is to alter the main axles to have the wheels run in ball bearings rather than aluminium bushes and have disc (bicycle) brakes on them. The front brake on the Sluka is ok but as Guy said also, it imparts a fair bit of strain into the framework. Brakes on the main wheels would certainly improve its manoeuvring turning circle to maybe three feet instead of 60ft !

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                    • #11
                      FUSELAGE CRACKS

                      Hi All,
                      Square tubes are easier to machine and fix things to but round tubes are lighter and probably better in twisting loads.
                      Boom tubes are usually driven by availability of material I suspect.( the Shadow one is a water drain tube from the local power station I am told)
                      If you find another replacement boom for your plane it needs to be the same material , size and manufacturing method to be successful as an easy solution otherwise the tests and paperwork would go on for some time and even then it would need some providence I suspect.
                      The approved LAA mod should be good because it effectively replaces the front of the boom with another inside and increases the support for the front wing through bolt.
                      You should consider this at an early stage even before you can see the cracks as its a known problem.
                      It might be good for a few of you to get together and produce the fix collectively to keep the price down.
                      Extra brakes might be possible but do not dismiss the small drum brakes as they are more efficient for the likes of planes than the discs but its all down to weight.
                      The engine change was a 508 fourstroke which is only practical for competitions due to its availability and fuel performance.
                      There is no reason why you cannot fix a 503 but the only advanage of the duel ignition is down to the removal of the points, it actually works better as a single spark.
                      Hope this helps
                      Mick
                      Mick Broom
                      Member 909
                      Shadow G-MWTN

                      Comment


                      • #12
                        FUSELAGE CRACKS

                        Hi Roger,

                        I have recently had the boom modified as I have added a 508 engine. The work I had done was more than necessay ie a slightly longer sleeve. I had the boom sleeved with a piece of sluka original boom, split and cut and and new saddles and new bolts(2) made. We reammed out the front holes to accept the new saddle. The sleeve was pop riveted all over to keep in place as requested by LAA. Because I also had made different engine mountings the whole lot was then load tested to cater for a heavier 508 engine. The loads for a 447 are much lighter in both weight and torque.

                        Give me a call if you want some information or email.

                        Regards

                        david 01227 700441 haddersd@talk21.com

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                        • #13
                          FUSELAGE CRACKS

                          Square tubes don't have anything like the tortional strength of round ones, If you can find a Spectrum, check the tail and see how easy it is to twist

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