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  1. Hot Wings

    How does this Hybrid work ?

    Several modes: Run the motor, from batteries, and the ICE at the same time. Lots of power for take off and climb. Run the Ice only for cruise with the option to recharge the batteries slowly for another climb, or just to have battery reserve if the ICE should fail. Run off whatever charge is in...
  2. Hot Wings

    Raptor Composite Aircraft

    That last flight didn't look so bad - until I saw the cockpit view. The low frequency roll response looked to me to be divergent and pretty well matched to what we can see of the motion of the left aileron. The higher frequency aileron 'flutter' seen in the stick starting about 13:58 doesn't...
  3. Hot Wings

    A practical UL trainer....or not?

    I've had this thought before. The only problem I haven't been able to solve is a way to simulate a plane with mechanical controls. With the stepper/servo driven controls there is no such thing as stick free stability mode. That could cause some transition problems when the student tries to...
  4. Hot Wings

    Elon Musk REVEALS Tesla's new battery design

    With sprinkles too.
  5. Hot Wings

    Elon Musk REVEALS Tesla's new battery design

    Looks like a huge investment in the cell factory - a variable that according to the slide has zero effect on range. The cell design costs look to be the only one that is actually paying for the development cost. At about a 2/1 ratio of investment/savings for the cell factory it may be a while...
  6. Hot Wings

    Elon Musk REVEALS Tesla's new battery design

    Maybe not internal resistance but less overall resistance. It does have a more direct and robust path to the terminals. My take is that the real advantages are the speed with they can be produced and because they can now build a bigger battery there are fewer connections needed in the final...
  7. Hot Wings

    Elon Musk REVEALS Tesla's new battery design

    The 5X energy increase is due to the 5.48X increase in the volume of the package from the 2170 to the 8046. The packaging is a pretty clever innovation, IMHO, but hardly worthy of the hype.
  8. Hot Wings

    Are tube spars an insult to the engineering community?

    Bean counter override formula ... (mu^x)/n which should be as low as possible. x>1* n= Need mu = Money Unit n to be sourced from the marketing staff or, if your own project determined by your personal bank account due to fixed mu value. * good scroungers can use a value for n <1
  9. Hot Wings

    Raptor Composite Aircraft

    Is there any runway like one of these here in the US where he might move for first flight? No dead zone for the BRS at these. :pilot:
  10. Hot Wings

    Are tube spars an insult to the engineering community?

    Changed quote I don't like either. I'm one of those structures nerds. But I see more reason to use a tube for a wing than for a fuselage. A tube can be an elegant engineering solution - depending on the project parameters. I've just never been interested in a project where the parameters...
  11. Hot Wings

    VW Heads Designed for Aircraft- Poll

    Agree. That is just human nature. Give us some margin and we will use it up - and then some. Solve the new problem, rinse/repeat. Depending on how you figure the generations we are on VW Aero G3 at the moment, maybe G4.
  12. Hot Wings

    Prandtl lift distribution for conventional configurations?

    No decrease in wing load - just a longer lever arm for the gusts to toss you around. Was not aware of that bit of history.....stored for future forgetting. :confused:
  13. Hot Wings

    VW Heads Designed for Aircraft- Poll

    That IS pretty much what we are trying to optimize, though not so much power/cylinder area but waste heat transfer from a limited area. On the VW the primary limit is the heat transfer from the exhaust valve. Solve that one and we may find another area to be the limit. Right now the...
  14. Hot Wings

    Prandtl lift distribution for conventional configurations?

    I've pondered that same question. 2 possible problems: The Prandtl distribution is only good at one point* on the performance curve. For a speed limited ultralight that may be an acceptable trade. Ultralights are already at too low a wing loading to allow flight in anything more than a slight...
  15. Hot Wings

    VW Heads Designed for Aircraft- Poll

    They don't need to be run WOT for extended periods to prove the technology. Once the head mass is heat soaked (at normal operating temp) it is just BTU transfer/time. RPM is only indirectly related to waste heat generation. Put a turbo on the Rotax to make the same power at 3600 rpm as it does...
  16. Hot Wings

    VW Heads Designed for Aircraft- Poll

    The heat pipe idea has been brought up before. It sounds good in theory but so far no one has spent any time implementing the concept. There are other already proven methods to remove heat from the troublesome exhaust valve. Both Porsche and the motorcycle world have spent a lot of time on...
  17. Hot Wings

    Help with removing snap ring please

    This type of retaining clip is notorious for raising a small ridge on the shaft. It's not generally enough to see but it is large enough to keep close fitting parts for sliding off. A quick touch with a file solves that problem. Yes, some of these clips are pretty malleable. Just squeeze it...
  18. Hot Wings

    Simple, proven, off-the-shelf industrial V-twin?

    Hadn't thought of this - kind of like some of the Leyland inertia bendix?
  19. Hot Wings

    Simple, proven, off-the-shelf industrial V-twin?

    I'd like the option to move my starter to the PTO side as well but haven't found an off the shelf reverse rotation starter. To be honest I haven't taken the time to find out what pitch gears B+S uses so I can sort through the available options. If you have this figured out and care to share...
  20. Hot Wings

    Simple, proven, off-the-shelf industrial V-twin?

    Have the failures been due to torsional stress or simple gyroscopic bending loads? I think Pictsidhe may have done the torsional math? I keep thinking about all of the direct drive chipper shredders out there. The huge metal disk has to have more inertia than the stock flywheel and they...
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