Turbo

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Everything posted by Turbo



  1. Turbo added a post in a topic What pitch to use on a 582 3 blade 68" Kiev 2.58 gearbox   

    Cowlove came up with a really neat & simple version of the hacman system using an inexpensive, small 12V diaphragm vacuum pump.  These things are used in some portable  medical devices, and are surprisingly easy to find online.  My greyhead's carbs have no drillings for throat vacuum, to be used as a source, so the vac pump was much easier to do.  I have installed his system on my engine, have used it to shut down the engine, but have not had the opportunity to check it out at altitude.  Cowlove shared a pic of his instrument panel with the Catalina at 14kft!  A nice side benefit is the ability to smooth out idle at any density altitude.  FWIW.
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  2. Turbo added a post in a topic INVERTED TAIL RIBS QUESTION   

    Just don't ever fly into icing conditions!  Maybe all that aft-body upsweep is sufficient to keep mud from the tires off of the H-tail.  That would be my worry, as it's difficult if not impossible to see any contamination on the tail from the cabin.
     
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  3. Turbo added a post in a topic INVERTED TAIL RIBS QUESTION   

    Hear, Hear!
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  4. Turbo added a post in a topic A simple, but worthwhile hack   

    Yes, Adelle clamps can be a real pain!  So can those little spring hose clamps, as they tend to distort, then not work right (at least the cheap ones do).  Correct me if this is a bad idea, but I've taken to using small cable ties to terminate fuel and oil lines instead.  I pull them tight with pliers, pulling against a crescent-style adjustable wrench open just enough to pass the tail of the zip tie through.
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  5. Turbo added a post in a topic Tail Wheel Swap to a Matco Pneumatic 8"   

    Thanks, Nick.  There are, for me, some keeper ideas here.  I think I will also install a bar to extend the rudder horns to the same width as those of the tailwheel.  The uneven spring pair is evidently offered as a way to mitigate shimmy, but with a left-turning prop, and hence greater on-ground P-factor thrust on the left side, I think I will break with tradition and swap the stiffer spring to the left side.  I think I'll keep my Maule TW for now. Plunka-plunka-plunka!
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  6. Turbo added a post in a topic INVERTED TAIL RIBS QUESTION   

    USA35B was used on Pacers and worked well.  Looks almost like a dead ringer for NACA4415, one of the most versatile of the old NACA  4-digit sections.
    For the H-tail, a serious consideration is mud splatter and other forms of contamination.  A thin flat plate can get to a max sectional CL of 0.7.  This is about as low as it goes, so it doesn't get worse with contamination, so for safety reasons aero designers just size the thin, flat-plate tail accordingly.  On more modern planes they've gone to thin NACA airfoil shapes that have less aerodynamic profile drag, but they too have low enough thickness ratio that their max CLs are low enough to not degrade much with contamination. They too are sized to the max CL when badly contaminated.
    The CH750 kinda scares me with its tiny, thick, highly cambered H-tail.  If it gets too contaminated with ice, mud, etc, and the stall CL is degraded too far, it's not inconceivable that the H-tail could be overpowered at some flap deflection, stall, and the plane suddenly noses over.  Speed won't help as it increases wing nose-down moment.  If the pilot is too close to the ground, or doesn't get what's happening, and pull up the flaps, he's toast.
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  7. Turbo added a post in a topic A simple, but worthwhile hack   

    Sorry, I just don't get what you're trying to say here.  Could you please re-phrase that?  Thanks.
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  8. Turbo added a post in a topic tank cap   

    The wing's boundary layer is surprisingly thin, order of 1 mm, so the vertical part of the vent does not need to be very tall.  I'd give it at least a couple of cm, though.   Having a forward-facing vent means if you happen to fly into a rain storm you will collect a little water.  To counter this I would overshoot on height a little, then come back down to put the forward-facing part parallel to the local wing surface, not the freestream direction. The amount of pressure you get from a forward-facing vent is around 1 kPa, not much, however with two wing tanks with similar vents you can be sure they will be very close to the same pressure.  The total pressure is the easiest to enforce.  By comparison, freestream static pressure is much more difficult to get right.
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  9. Turbo added a post in a topic A simple, but worthwhile hack   

    Gotta try that one!
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  10. Turbo added a post in a topic On 2-stroke oil...   

    At this point, at least per my reckoning, the dead horse has been beaten well beyond horse-purgatory.
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  11. Turbo added a post in a topic 582 no spark   

    I was there a while ago.  With only 0.016"- 0.020" gap, the spark is too weak to see in daylight.  I hooked up a cheap ignition flash lamp, and it flashed.  Whew!  Had bailing wire wrapped around the plug base to ground and all.  Couldn't see it!
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  12. Turbo added a post in a topic On 2-stroke oil...   

    I believe it.  Got a bottle of the pride of Mazatlan (Pacifico) open and am feeling more sanguine already!
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  13. Turbo added a post in a topic On 2-stroke oil...   

    Thanks, JimChuk,
    That was precisely what I was avoiding.  The oil companies all promote their product with, well, propaganda!  However, there was a lot of info on oils of which I was ignorant, so I thought a share was appropriate.  But the real point had to do with oil testing against standards.  Hell, I have not yet found a JASO-FD rated oil that I like the price of!  But no way was I going down the classic rat-hole!  Too much superstition afoot.  Maybe I need a beer.
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  14. Turbo added a post in a topic On 2-stroke oil...   

    Should I now say that I know who to avoid if we ever have a fly-in?  These two gentlemen just violated the first rule of this site, and one is a moderator!  Hey, like so many of us, I'm just a little old guy trying to dig into what might be pertinent details to make sure my prop doesn't stop unexpectedly.  Like each of us I process information in my own, unique way.  These two offended me.  What did I do to evoke such unkind responses?  Any apologies tendered will be accepted, of course.  Was I delusional to think of you all as friends I have yet to meet face-to-face?   
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  15. Turbo added a post in a topic On 2-stroke oil...   

    Such a display of kindness.  Thanks, guys.  Apparently y'all didn't notice my focus on standards.  The oil companies all claim to produce the best oils, ergo my use of the word "mysterious" in my first post on this.  
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  16. Turbo added a topic in Technical tasks   

    A simple, but worthwhile hack
    This hack may be well known to many of you already, but it came as a sudden epiphany to me the other day.  
    I was trying to install a washer & nut in a location where my fingers could not go - underneath a plate atop the engine.  I couldn't hang on to both for the install, but could easily turn the bolt from above.  Finally, I cut off a square piece of duct tape and stuck it to the bottom of the jaws of the open-end wrench I was going to use to hold the washer & nut, and keep the nut from turning.  The tape temporarily held both washer & nut on the end of the wrench.   This allowed me to place them on the end of the bolt where my fingers couldn't go, while I rotated the bolt from the top!
    There must be dozens of hacks y'all have created over the years.  It would be great to hear them!
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  17. Turbo added a post in a topic On 2-stroke oil...   

    Nice, definitive statement, however oil technology and standards continue to evolve.  JASO (Japan Automotive Standards Organization) has developed a refinement over its FC standard (essentially equivalent to ISO-TC).  The New standard, JASO-FD, further limits the amount of ash allowable from 0.25% or less down to 0.18% or less.  Some ash is beneficial for hot-running small, high-revving engines, as the higher temps tend to burn off the excess, and as explaned above, that ash creates a second layer of protection in the event of the oil failing to lubricate at too-high temperatures.  Our liquid-cooled 582 engines don't go to those high temps, so the excess ash ends up building up on the combustion chambers' interiors.  The lower ash levels mandated by the JASO-FD standard would seem appropriate.  Any JASO-FD - rated oil also satisfies the ISO-TC standard.  FWIW - Turbo
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  18. Turbo added a post in a topic 582 Fuel requirements   

    The newer gas cans, especially the Canadian-made polyethylene ones, can sustain the 7- to- 9 psi vapor pressure (significantly less pressure if temp is lower than 100F).  Am I wrong to assume that I can store, for long duration, mogas in a sealed container?  If so, why?  I routinely do this and see no ill effects.  My engine starts & runs just fine.
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  19. Turbo added a post in a topic On 2-stroke oil...   

    One of the not-so-surprising takeaways I got was that oils branded with a manufacturer of lawn & garden equipment, like Stihl, Huskvarna, Echo, Poulan, and Deere, etc. Are almost always rated JASO-FD, which, at least by meeting that spec, makes them good choices for us.  The small amount of ash, 0.18% or less, is put there intentionally as a secondary layer of protection, and can be things like ZDDP, or other slippery solids.  This could prevent scuffing in an overheat situation, but leaves deposits.  Ashless oils lack this backup protection, but leave less stuff behind.
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  20. Turbo added a topic in Two Strokes   

    On 2-stroke oil...
    I was wondering about 2-stroke oils, and wandering online found this deep dive into that mysterious world: http://www.dragonfly75.com/moto/oil.html 
    Some interesting take-aways:
    The word "synthetic" is not particularly meaningful, as some oil companies apply it to oils that are petroleum based, but just super refined.  Apparently that's legal.
    The reason ethanol is a no-no for us is that it often doesn't evaporate instantly upon hitting the opposite cylinder wall, diluting the oil film there!  (This, in addition to the fuel tank slowly dissolving!)
    More oil than the 50:1 recommendation apparently will reduce ring-and-cylinder wear.
    More oil than the 50:1 ratio apparently increases ring sealing, compression, and max power output!
    Overall, it's a longish, but interesting read.
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  21. Turbo added a post in a topic Autumn light over the mountains   

    Le 2CV du l'air!  How apropos.  Some may not recall that diminutive Citroen.  Great pics of some rugged terrain, Fred!
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  22. Turbo added a post in a topic North Idaho Mountain Flying   

    Awesome!  I'm seriously jealous!  
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  23. Turbo added a post in a topic Soggy Plugs   

    It just occurred to me that the place to put a fuel filter is downstream of the header tank, which really is a huge gascolator, i.e. a water trap!  Note that the outlet of the header tank is above the bottom, which is where the drain is.  That's a lot of volume for trapped water.  In my plane, there was a paper inline filter just below the fuel tank, behind the seatback.  When I took it off, I found it had a small amount of trapped water.  I am moving the fuel filter to the engine compartment, just ahead of the fuel pump.  I expect it to not accumulate water there.  
     
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  24. Turbo added a post in a topic Soggy Plugs   

    Silly me!  I keep going to auto parts stores instead of places that sell & service snowmachines!  Thanks for the tip, JimChuk!
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  25. Turbo added a post in a topic Soggy Plugs   

    Just swapped out the paper filter in my fuel line for a screen.  I intend to test the new screen for pressure drop.  Burning pre-mix, that old filter had some water in it, yet was still flowing pre-mix with negligible pressure drop.  Maybe the oil in the pre-mix wetted the paper, trapping the water.  Maybe fuel alone would do the same.  I could see a scenario where that paper filter could be inundated with so much water that it could stop flowing, though. The very small pore size makes surface tension a much more powerful effect.  Without being able to wet the paper with water, I can see how the pressure drop required to push the water thru that filter could be large.
    Where I am contemplating using a paper filter is only in the oil line to the oil injection pump.  Went online looking for a screen filter in 5/16" line size, and couldn't find one.  I am going to locate that filter where it is easily inspected.  The much smaller OI tank should not suck in anywhere near the amount of water that a wing tank would.  I intend to keep the oil tank full when stored.  
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