Ah-1 Cobra Pilot

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About Ah-1 Cobra Pilot

  • Rank
    Full Member

Profile Information

  • Gender
    Male
  • Location
    Lincoln NE
  • Interests
    Flying, duh!
  • Reg #
    N468W
  • Model
    M20J
  1. Engine out glide distance

    There is a HUGE difference in glide performance depending on a few things. 1. Is your engine barely running? If so, it will not provide thrust, but may allow you to feather your prop. Anyone who flies twins can attest to what happens when you change your prop pitch in flight. Most twins have the prop set to go to feather if the engine fails in flight; singles do not. (In fact, most singles' prop systems fail to the max rpm mode.) It also makes a big difference how many rpm your engine still has. Some rpm is the zero-drag-point, with higher rpm producing thrust and lower rpm producing drag. 2. Is your prop stopped? Big difference in drag between windmilling and stopped. 3. If your prop is windmilling, throttle open or closed? Less engine resistance with a full-open throttle reduces drag. If you really want to give us all some good numbers from your experience, please test all of these and let us know.
  2. Ice

    That is nothing; no lollipop!
  3. Insurance valuation

    I have to think the insurance companies know what your plane is worth, (replacement cost), and will not insure it for much more than that. Otherwise, it would invite fraud.
  4. Insurance valuation

    I ran VREF. Since you did not give a TT, I used the standard 4040TT. It gives credit for the GTN-650, EDM 380, Strikefinder, Alt Hold, and nice interior, but, surprisingly, nothing on the G5s. End result is: 1967 - MOONEY SUPER 21/EXEC M20 E/F $65,400.00 (as configured) I have been thinking a lot about this, too. I bought my 201 about 2 years ago for $69,500. VREF now shows it worth about $84,000. Replacement value is foremost in my mind, as my dad landed his T-210 gear-up recently, and the repair bill was quoted between $80,000 and $110,000! Unbloody believable, as the only visible damage is 3 square feet of skin and the prop. ( He made a perfect landing. The investigator noted 16 prop slashes on the centerline.)
  5. 350HP Mooney

    The equations I am using apply to the engine directly. I avoid discussing propellers much, as their efficiencies can vary more widely. Keep in mind, all these numbers are VERY approximate and presume more-or-less flat curves in the changes. Speed vs. horsepower is also easy to figure out. If the new Acclaim does 242 KTAS with a 280 hp engine, what would it do with a similar-design 400 hp engine? 400/280 = x3/2423. Thus x = 272.5 KTAS, (all else being equal, of course). So you could add about 30 knots for about 43% more fuel burn.
  6. 350HP Mooney

    Lots of weird numbers coming up on this thread. You can make some pretty good estimates as to horsepower and fuel consumption using these. (Keep in mind, the numbers presume roughly stoichiometric flow.): As memory serves me, these are the common Specific Fuel Consumptions for these engine types: Turbine = 0.43, gasoline recip = 0.36, diesel = 0.34. All are in lbm/hp/hr. As you can see, recips are 20-25% more efficient than turbines for the same horsepower. The big difference is that turbines lose less capability at high altitudes. You can also make your own estimations, such as this. "I doubt it’s making 450HP if it’s only burning 17GPH." Absolutely correct. 17 gal/hr * 6.8 lbm/gal ÷ .43 lbm/hp/hr = 269 hp. (I use 6.8 lb/gal for jet fuel. There may be some fudge to that.) You can also use this to correlate your fuel burn with your presumed %-power. i.e. a J-model at 75% power should burn...150 hp * .36 lbm/hp/hr ÷ 6 lbm/gal = 9 gal/hr. Again, this is best-case-scenario. If you run rich, your results may will vary. I think a little Math can make us all better pilots. Please try it for yourself. P.S. I may be too low on the recips. This gives 10 gal/hr for the J-model, if you accept the number for the IO-720 here: https://en.wikipedia.org/wiki/Brake_specific_fuel_consumption
  7. 350HP Mooney

    I use 37:1 compression ratio, so better thermal efficiency. Then, I have a long expansion stroke, and very little reciprocating mass. Gasoline actually has a higher energy density than diesel. 20260 BTU/lbm vs. 19110 BTU /lbm. Diesel has more energy/gallon, though, 138110 vs. 116485 BTU.
  8. 350HP Mooney

    No, nothing like the Wankel. I use separate compression and combustion epicycloidal chambers with a sliding vane in each.
  9. 350HP Mooney

    They are probably exaggerating a little. That yields a SFC of 0.28 or 0.327 lb/hp/hr, (depends on your presumed fuel density). A good Caterpillar diesel gets about 0.34 @ 1050 rpm. https://s7d2.scene7.com/is/content/Caterpillar/LEHW0058-00 If you are truly interested in higher powered engines, I have a rotary engine patent, and I even wrote my Masters Thesis on its analysis. A 127 cu in engine turning 2700 rpm should produce 380 hp @ 2.4 gph. If you have $2,000,000 to invest, (I guarantee a return between 0 and 50,000%), please PM me.
  10. Not terribly happy with FF scout

    As an entrepreneur/small business owner, I see this kind of thing all the time...It was designed and built by guys with good electronics skills and lousy plastics knowledge. The Tg was obviously too low, but they were in such a hurry to get it to market, they did not do diligent research.
  11. Tires: Air vs Nitrogen

    That is interesting. I would have thought it would be the opposite, since O2 has a molecular weight of 32 vs. 28 for N2. I always thought the selling point for pure nitrogen was the avoidance of oxidation inside the tire.
  12. Introductory Light Jet flight?

    Here you go. https://www.barnstormers.com/classified_1299752_Bede+5B.html
  13. Anyone have a spare windshield OAT gauge

    Are you looking to drill a hole in your windscreen? I have seen that done on other aircraft, and it seems to work well. It is also the first place to catch ice, so it makes a good warning. It would scare me to risk a windscreen crack, though. Some boob mounted my OAT probe on the aluminum baffle right in front of the right-front cylinder. (Pun intended.) I constantly get readings that I know are too high. My mechanic suggested relocating it to another location, but what he suggested as easiest also put the probe where it would constantly snag on anyone checking the oil, etc. Any recommendations as to a new probe location?
  14. $500 FOR A SWITCH???? DAMN!

    Wow. I guess I can charge more than I thought for those switch covers.