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  • #16
    Four Stroke V Twin progress

    First setback; running the engine up to revs and the fan let go with a bang, damaged the casing and took some of the plastic outer shielding off the ignition Mag units.

    Buggeration!

    Turns out the steel mesh fan screen braces it against centrifugal forces, take it off and it weakens the bloody plastic structure. When some excited idiot starts revving up the thing it needs bracing.

    Ordered a new fan, fixed the light damage to the ignition units with epoxy and ran it up to test sans cooling shrouds, all OK. The Americans advise bracing the fan across the fan fixing screws, or refitting the screen.

    Did consider binning the lot and going the free air via cooling duct route but in the end stuck to plan A, fan cooled.

    Kev
    G-KEVA
    BMAA 5696

    "If anybody ever tells you anything about an aeroplane which is so bloody complicated you can't understand it, take it from me: it's all balls."

    R.J. Mitchell :- Designer of the Supermarine Spitfire

    Comment


    • #17
      Four Stroke V Twin progress

      How do you know what revs you ran when the self distruct happened Kev? Running without a prop is a dangerous exercise. (Running with one is even more dangerous - but only for you...)
      Dave

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      • #18
        Four Stroke V Twin progress

        Hello Kev.

        You might of wrote previous so if I missed it, apologies, but what prop are you thinking of?

        Having just read the superb Hercules story in LAA mag it begs the question whether he's your man!

        Spoke to him re a prop for my Hawk but the hassle/price of a noise test put me off big style.

        Good luck and please talk to E-go about your engine because I am not happy with the thought of a white hot rotary slowly melting away my arse at 10k without me knowing about it. Thinks I will fit a Spitfire style rear view mirror to watch for smoke!

        Hugh.

        Comment


        • #19
          Four Stroke V Twin progress

          Just built the exhaust headers, used two 90 degree and one 45 degree elbow per side, 1.5 wall in 32 external to get the right internal for torque, as found on the online exhaust tuned length calculators. To get as much length as poss but keeping it compact, I had to send them over the redrive and down the other side. Can still get to the clamping bolts to allow belt adjustment on the eccentric shaft

          Stick tack-welded it up on the motor, bolted to the head by laser-cut exhaust flanges, then off to Fab Shop to get one of the lads to TIG it all up properly after grinding my pigeon-poo off ;-)

          Got 690mm header length and need to join them at 915, so need to make a Y piece join the two pipes within 235mm or 9 1/4".

          We tend to ignore exhausts but this was bloody hard work to create.

          Cheers

          Kev

          Dave Smith wrote:
          Fabulous!
          Got your hearing back yet?
          Particularly liked the petrol feed tube just grazing the prop pulley, and being licked by the exhaust...
          You should be able to tune it on the colour of those exhaust flames (remember the Colotune?).
          Can't seem uch vibration.

          Dave
          Attached files
          G-KEVA
          BMAA 5696

          "If anybody ever tells you anything about an aeroplane which is so bloody complicated you can't understand it, take it from me: it's all balls."

          R.J. Mitchell :- Designer of the Supermarine Spitfire

          Comment


          • #20
            Four Stroke V Twin progress

            Accounted for the 270 degree firing offset into the 'Y' Kev?
            Dave

            Comment


            • #21
              Four Stroke V Twin progress

              Where'd you get the Metalstik bushes from and how did you select them?
              Dave

              Comment


              • #22
                Four Stroke V Twin progress

                Looking good Kev!

                Comment


                • #23
                  Four Stroke V Twin progress

                  That looks amazing Kev. - It puts my current project into perspective (moving the Rocket's horn from the front to under the side panel - with my skills that will probably take longer than your engine project)
                  BTW - what Honda's have silencers like that
                  Mike

                  Comment


                  • #24
                    Four Stroke V Twin progress

                    ..... and what's the Honda silencer's weight Kev?

                    Comment


                    • #25
                      Four Stroke V Twin progress

                      Kev, I am sure you are aware, but I suggest that before you decide on your battery, especially if going for a LiFePo4 type that you measure the Cold Cranking current drawn by your engine (anything up to 200 Amps) and remember that the CCA quotes are usually for 10 seconds!!!!!!!!!!!!

                      If you are also not aware a couple of companies in the states sell their batteries specifically stated as for use in aircraft.

                      http://www.aerolithium.com

                      and

                      http://www.uflyit.com/index.html

                      Comment


                      • #26
                        Four Stroke V Twin progress

                        Equally both impressive and scary! Being in a confined space that close to so much energy I think I'll leave to you & other engine experts.

                        Looks good!

                        Mike

                        Comment


                        • #27
                          Four Stroke V Twin progress

                          Mike Cowlishaw wrote:
                          Equally both impressive and scary! Being in a confined space that close to so much energy I think I'll leave to you & other engine experts.

                          Looks good!

                          Mike

                          True, Paul Dewhurst kindly posted earlier to remind about restraint to the top of the engine, and after all the other stuff it was time to have a think. Just cobbled up a top bracing to take the upper reactions into the seat frame, re-used the original engine bearers and a couple of 50mm Lord mounts, this may qualify for the prize of 'Worlds Ugliest Engine Mount'. A follow on project would be better with steel tubes curved into a plate or bobbin rubber.

                          But it works well enough.

                          Doing the numbers was interesting; an engine mount has to take 15G forwards, and 40 times 15 equals 600 kilos, add in 1:1.5 safety factor and you're at 900 kgf.

                          Split that top and bottom though and its 450 per top and bottom set, 225 per mounting ultimate, working 150kilos force per leg, so doing a radial or multi link mount cuts the forces hugely.

                          Kev

                          PS 0.75 kilos over 115; looks like that expensive battery is on the cards, or trying a smaller one as the Vangaurds starts so well on a YTX 9BS Yuasa
                          Attached files
                          G-KEVA
                          BMAA 5696

                          "If anybody ever tells you anything about an aeroplane which is so bloody complicated you can't understand it, take it from me: it's all balls."

                          R.J. Mitchell :- Designer of the Supermarine Spitfire

                          Comment


                          • #28
                            Four Stroke V Twin progress

                            Leave the battery behind (or carry in your flying suit) ;-)
                            Have you made a loose collar for the cylinder head end of those links?
                            Could almost do with a rubber 'grommet' of some sort.
                            I'd keep a careful eye on the bolts there, as there's a lot of flexing going on.
                            Dave

                            Comment


                            • #29
                              Four Stroke V Twin progress

                              Steel sleeve bush over the 8mm bolt, thicker alloy spacer underneath and locked down tight but clearance hole in the alloy arm, so the arm can pivot and swivel on the steel bush Dave, well spotted that man, I did think of using a Rose joint but in the end alloy runs on steel pretty well, if it wears too quickly will use a nylon or bronze bush. Slight clearance under the bolt head/washer to allow small movement in other planes.

                              Bolt is being changed for a caphead Allen bolt as it are easy to drill the head for lockwiring.

                              Cheers

                              Kev

                              Dave Smith wrote:
                              Leave the battery behind (or carry in your flying suit) [IMG]/emoticons/wink.gif[/IMG]
                              Have you made a loose collar for the cylinder head end of those links?
                              Could almost do with a rubber 'grommet' of some sort.
                              I'd keep a careful eye on the bolts there, as there's a lot of flexing going on.
                              Dave
                              G-KEVA
                              BMAA 5696

                              "If anybody ever tells you anything about an aeroplane which is so bloody complicated you can't understand it, take it from me: it's all balls."

                              R.J. Mitchell :- Designer of the Supermarine Spitfire

                              Comment


                              • #30
                                Four Stroke V Twin progress

                                Allen bolts usually 10.9 or 12.9. Too brittle. Don't go above 8.8 hardness.
                                Dave

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