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danny_galaga

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Everything posted by danny_galaga

  1. danny_galaga
    Agreed. I've seen it, having been an auto electrician, but it's not common. But what I'm driving at I guess is you increase the risk of it happening if you get a cheap solenoid. The contacts might not be as good a grade of alloy, or not very well aligned etc. So the original thrust of this thread was to find a reputable solenoid brand I could go with that is available in Australia. The mercruiser one was mentioned, but hard to know if I'm getting the real deal or not. But everyone can stop looking, because I've discovered a popular Rotax engine that uses the same Denso solenoid 🙂 https://www.rotax.com.au/shop/item/starter-relay-evo Which you can get from Go kart shops etc. My journey is done, and I'm also fitting a starter indicator light as well thanks to this thread. Thanks guys!
  2. danny_galaga
    I think I've covered all that in previous posts. If engine continues running with solenoid fused, starter destroys itself through centrifugal force because the starter will remain engaged with the engine. Ratio of pinion to ring gear is easily 20:1 so even if the engine is only running at 1000rpm, the starter is spinning at 20,000rpm! If you stop the engine, then starter keeps spinning the engine over until battery goes flat, or starter melts down. As you alluded to before, starters don't like cranking for long..they get hot really quickly. If it has field windings, the insulation burns up causing shorts . And whatever type, the armature windings can also short out if very hot. The brush tags, if soldered can melt off. If the armature has soldered commutator segments, those can also melt. Molten solder is a saving grace in this case because everything becomes open circuit very quickly. The only way the starter would keep spinning for any length of time is if the pinion clutch failed, or didn't engage the ring gear. Then the starter would spin quite happily for ages. Although that would give you plenty of time to disconnect the battery 🙂
  3. danny_galaga
    Agreed. But it won't be long before either the battery is flat or starter has melted down if the solenoid is fused. The voltage will drop extremely rapidly once it's been cranking for a while. This is because at rest a starter has virtually no resistance. When it is spinning it produces back emf. So at the instant of start, it might draw 500 amps, and within a fraction of a second, it is drawing only 100 amps because it is spinning. But say it gets down to maybe 8 volts. Now there isn't enough voltage to spin the starter, or at best very slowly.so it's virtually presenting as a dead short again to the battery. Now instead of only 100 amps, it's drawing 300 amps. At 8 volts it's discharging at 3 times the rate it was at 12 volts! The figures are just ball park to illustrate, but you get the drift. I'm not saying that's a great thing to happen, just pointing out all things being equal your battery will be quite flat quickly in that scenario, or the starter will burn out, going open circuit. I'm in two minds about adding a battery isolator. Yes, it could be safer but I'm also adding more and more weight and complexity. A ballistic chute thingy would make my plane safer too. Where does it all stop? But you have sold me on the warning light 🙂
  4. danny_galaga
    I should add that a light on it's own isn't going to save your starter motor. You will need a battery isolator as well. I haven't got a battery isolator in my plane, might add one later. But the warning light will tell me the contacts are fused and best not to take off. All I can do at that point is shut off the fuel. Motor will stop, and starter will keep cranking till the battery goes flat or it burns out 😃
  5. danny_galaga
    All you need to do is run one wire out to the starter side of the solenoid, and the other to negative bus. Then it only comes on when starter is cranking. If contacts stuck, light will stay on. If you wanted the reverse logic, you would have one wire on starter side, and the other on positive bus. Since a starter is almost a dead short at rest, in effect it is negative until you start it. So in that case the light would be on all the time except when starting, or contacts fused, or the internals of the motor are totally obliterated! Not really any point, I'm just showing off 😄
  6. danny_galaga
    I think I might do that. But 'saving your life' might be dramatic. When a starter stays engaged, it gets spun up to higher revs than it's designed for. The armature windings start to move out, and at some point they, or the commutator segments fly out and arc out against the housing. As you would probably have seen, it's a big explodey mess inside the starter, no doubt. But once everything has fallen away the arcing stops pretty quickly. I take your point though. It would be yet another one of a large number of things that can rob your engine of power on take off. In this case, the loose chunks of copper etc inside the starter can cause extra drag on the engine. I'll pop in to Jaycar aeronautics and get a small panel mounted LED. I'll mount it where the key points at the starter position 🙂
  7. danny_galaga
    I wish I could re edit posts more than 2 minutes later. I meant PLANE, not PARTNER 😅
  8. danny_galaga
    Granted, I don't have enough experience to have had an engine failure (yet) but seems to me this issue the ideal situation to be landing the plane, rather than locking in the destruction of your partner by pulling the chute? https://www.avweb.com/aviation-news/285055/
  9. danny_galaga
    I can keep it simpler by just using a good solenoid. What brand have you got? Is it the original Rotax part?
  10. danny_galaga
    So what are you guys using for your Rotax or Jabiru starter motors? I just ordered some bits and pieces from overseas and thought I had included a Nippon Denso relay in the order. Looks like I forgot it, so if there's something thats proven amongst you guys I can get locally I'll do that. FYI, the Rotax part is a denso starter relay part number 182800-1950. It's less than half the price of a 'rotax' one. Pretty much anything around that size will do, including the knock off version. BUT.... if I use a $20 relay, and the contacts fuse together, it wasn't much of a savings if my starter motor goes nuclear 😄 I tried looking at other similar relays to get a feel for what's out there, but hard to tell without specific part numbers for each. I looked at relays for Honda CB900, BMW R1200, Polaris, Harley Davidson etc When I was a sparky, the solenoids we used for cars were fairly cheap, but blowing up a Rotax starter is a different ballgame to blowing up a Cortina starter 🤣
  11. danny_galaga
    Simplest thing I can think of without mucking around with aerodynamic mods is to add an extra oil cooler inline with the existing one. Almost anywhere you mount it will add some extra cooling, even if on the firewall, unless of course it's right next to the exhaust 😄
  12. danny_galaga
    https://bydanjohnson.com/mosaic-ready-powerplant-brp-rotax-surprises-sun-n-fun-with-a-powerful-new-announcement/
  13. danny_galaga
    From this it implies Rotax themselves say 48 month shelf life https://www.rotax-owner.com/en/912-914-technical-questions/9671-912-fuel-pump-shelf-life?start=0
  14. danny_galaga
    Yes, that has crossed my mind, that the rubber might perish just sitting there. I will investigate. My garage is cooler than my house, so heat shouldn't be an issue
  15. danny_galaga
    Dunno if it helps, but at least some perspective from a different system - on the Bushcat, there is one small oil cooler above the radiator. Radiator is in much the same position as the CH701 as far as I can tell. Then another small oil cooler on top of the engine. The cowl ducts air straight to the cooler ( no hoses) and then straight out again, going over the windscreen.
  16. danny_galaga
    Looking forward to hearing more 🙂 I may buy one or two and store in my garage for the next five year replacement.
  17. danny_galaga
    Of course I've just gone and ordered a Rotax one 😂 But that part number goes in my list of spare parts now. Thanks for the info. Might buy one of these as well. How long have you run this one? Do you know if others are using them?
  18. danny_galaga
    It's what I'm getting at. Surely they can go to ten before replacing? If not, then surely a safer system would be better. Or at least the option.
  19. danny_galaga
    Are you replacing your gearbox every five years 😄
  20. danny_galaga
    So no one knows about the company I linked to in the first post? Or another like it?
  21. danny_galaga
    This is all true, but if you specifically talk about mechanical diaphragm fuel pumps, I've never heard of any car fuel pumps having to be replaced every five years. Were a y of the diaphragm pumps you replaced less than five years old? Or were they 30 year old EH utes etc? While it's true an aircraft ENGINE has a harder time of it than a car engine, I don't see that an aircraft FUEL PUMP is under that much more duress. And if so, then ditch the diaphragm, and go with a piston design (which I imagine was the Billet Pump solution) . They had tested theirs to 2500 hours, which is 500 more than the engine is supposed to go for. If non rubber diaphragm, you don't have the time constraint, just hours operated, like the rest of the engine. It did sound like the Billet Pump fuel pump was more expensive than a standard Rotax one, but since it was supposed to last longer than the engine, you would no longer have to worry about it. Look at it another way. You used to be able to rebuild fuel pumps. Not so the Rotax. Nice little earner for Rotax. Why sell you a $100 kit, when you can sell a whole pump?
  22. danny_galaga
    And yet the equivalent in an older car, in constant contact with the same fuel it would go decades. If it can last decades, I think replacing after ten years is more reasonable. Anyway, what's the point of the electric pump if you don't get to use it occasionally in an emergency 😄 In any case, my big question is, is there anything out there like that Billet Pump solution for Rotax? From what I can tell, there is no diaphragm to perish.
  23. danny_galaga
    I found a link to something that would have been a great replacement, but it seems to be a dead end. For whatever reason, they didn't catch on http://www.billetpump.com/ Is there anything else like this out there? For now, I've just ordered a genuine fuel pump, but it is a bit of a gyp isnt it, having to replace them every five years. In the automotive world, with their 'made by the million' specs, diaphragm fuel pumps easily lasted decades. It seems nonsense to me Rotax fuel pumps cant last at least ten years. Are they made by Ducati, like the regulator/rectifiers? 😄
  24. danny_galaga
    Latest item is the regulator/rectifier. I got a Carmo. Less wires and runs cooler. Made in the Netherlands. HUP HOLLAND! HUP! 🙂
  25. danny_galaga
    TRue, but still not really an item I need to put in my list of substitutes for OEM stuff. There's no specific call for that tape on my aircraft
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