Recent content by djschwartz

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  1. djschwartz

    Headseat Microphone VOX sensitivity

    The problem with the internal "intercom" function in all of the aircraft radios is that it is not a true intercom. When the VOX circuit activates it simply makes all of the mics in the aircraft hot. So, you get the noise picked up by all of the mics on top the the voice being picked up by only...
  2. djschwartz

    Why so few V-Tails?

    Another disadvantage of V tails that has not been mentioned here is trim drag. If the aircraft is balanced such that there is little load on the tail to maintain level flight then the V tail will have very slightly less drag than the conventional tail due to the reduction in interference drag...
  3. djschwartz

    Anyone Familiar With Rejuvenator

    A simple Google search brought up this from the manufacturer: Poly-Fiber Aircraft Coatings
  4. djschwartz

    Current Limiter In Starter Circuit

    You have other issues to consider. If the two batteries are simply connected in parallel and one battery goes dead the other battery will attempt to charge it and go dead itself quite quickly. I would install a diode battery isolator in the charging circuit and then contactors controlled by...
  5. djschwartz

    Prop tip speed in cruise vs. hp & torque. Is bigger better?

    Torque is irrelevant to such estimations. If you assume all other factors, aircraft weight, drag coefficient, propellor efficiency, are unchanged, then speed varies as the cube root of power. That is a simple calculation. The problem is, of course, that when comparing two different power...
  6. djschwartz

    Prop tip speed in cruise vs. hp & torque. Is bigger better?

    The helix angle at any given point on the propellor blade is the arc tangent of the forward speed of the aircraft divided by the angular velocity at that point on the blade. For the example above that cites a roughly 470 MPH tip speed, if we assume a 200 MPH cruise speed the helix angle at the...
  7. djschwartz

    VG stall angle improvement

    I've actually not seen Bud fly the Yak. I have other aerobatic friends who have tried VGs with mixed results. This is not because VGs are bad in any way but because they were doing exactly what was intended, delaying stall. With the VGs the aircraft would pull around a corner at high angles...
  8. djschwartz

    VG stall angle improvement

    Often a quick search can turn up some real information. For example, a Google search on "airfoil polars with vortex generators" turned up this report from Ohio State University for the NREL titled "Effects of Surface Roughness and Vortex Generators on the NACA 4415 Airfoil"...
  9. djschwartz

    Dyn'Aero in trouble?

    Having been around the homebuilt scene for 40 years now it's pretty easy to understand what is going on. Van's planes and his company do what they claim. Sure, they're not perfect, but they're darn good and there's little hype. Few in the industry come close on the "say what you do and do what...
  10. djschwartz

    Bush plane, mabe?

    +1 on the stay in school and do well there, that's a good start for life in general. As for aviation, join the Experimental Aircraft Association. The national organization isn't much use anymore for ordinary folks like us but the local chapters are filled with great folks that are part of the...
  11. djschwartz

    Being practical with the homebuilt.vs. certified decision

    An IA pays for a subscription to the ADs. Any reputable IA should be able to look up all the ADs and service bulletins for you aircraft. That's a required part of an annual. If you doubt the IA's efforts in this regard then I would also be suspicious of other aspects of the "annual" he performed...
  12. djschwartz

    Firewall! SS or Titanium?

    There is no advantage to titanium other than weight. Thin titanium sheet can be sheared and punched with the same light duty tools you would use for stainless; however, titanium is stiffer than stainless and work hardens when formed so bending tabs will be both more difficult and present the...
  13. djschwartz

    Carb Ice on Corvair Conversions

    If your carb or throttle body is mounted directly to the cylinder head as with the original ones in the car you are unlikely to have any icing problems as the carbs are heated by contact with the heads. If you plumb the engine for a remote mounted carb then you should have carb heat available...
  14. djschwartz

    Marvel Schebler Carbs

    The model numbers have to do with several things, among which is the main jet size. The only way you'll figure out which one might work on a Corvair is to find someone who has used one successfully on a conversion very similar to yours or to just buy one and start experimenting. Dave
  15. djschwartz

    Interest in a magazine or site focused on affordable flying?

    If it actually had real, verified, and useful information, not just a bunch of whining about high cost, "vapor ware" wishful thinking, rumors, and overblown hype I would be interested. Otherwise I wouldn't waste my time, much less my money.
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