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Thread: Cowl-flap as speed brake?

  1. #31
    steveinindy's Avatar
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    Bob, quick question : which manufacturers are you using for the LEDs? I am trying to decide on them for my LSA. Ron I never would have thought of that. How would one overcome that? Perhaps like the little wires embedded in the rear window of cars?
    Unfortunately in science what you believe is irrelevant.

    "I'm an old-fashioned Southern Gentleman. Which means I can be a cast-iron son-of-a-***** when I want to be."- Robert A. Heinlein.



  2. #32

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    Quote Originally Posted by steveinindy View Post
    I never would have thought of that. How would one overcome that? Perhaps like the little wires embedded in the rear window of cars?
    That is one way. Blowing hot air into the cavity is another. Having an arcraft design that handles the ice is another (or putting the light in a place that doesn't ice (like some airplane bellies). An advantage of LEDs is the potential for smaller frontal area. I have also heard of people using the "frame" as a heat sink for the electronics.

    Ironically, this is not a big problem as airplanes large enough to have FIKI normally have extra "power" to deal with the situation, and those that don't have the power, normally aren't FIKI approved.

  3. #33
    prasmussen's Avatar
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    Quote Originally Posted by Ron Blum View Post
    Bob: I like the out of the box thinking; combining functions is always a good thing. But, the problem with cowl flap speed brakes is that when you most want them open (takeoff/climb) you don't want the added drag, and when you want the drag (coming down) you want the engine cowled to keep it warm. I also like Tony's comment: Plan ahead.

    Nobody has mentioned slipping the airplane either. Oh, that's right, we don't teach using your feet anymore (tic).
    Those of us who enjoy making things work have four problems when that compulsion applies to airframes:

    1. Complexity adds to the weight; controllable and retractable mean pounds,

    2. Adding to your work load, even slightly, may be something you regret someday. Even I, who am, of course, the worlds greatest pilot, have tried to land with the wheels, prop, spoilers and my brain in the wrong place. Thank God not all three at once....... yet.

    3. Don't know which Murphy's law it is but the more ways you give a device to break, the more often it will. Simple tends to be reliable (remember how the Vanguard rocket got us into trouble?).

    4. You will enjoy the time you spend building the perfect machine but would you rather be flying with those hours? Should we admire your skill as a pilot or marvel at the machine you have designed? It's all good.
    Last edited by prasmussen; 05-07-2012 at 03:22 PM.

  4. #34

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    Nobody has mentioned slipping the airplane either.
    Hey, I did!



    LED's with a frenel lens - brilliant thinking!
    The opinions and statements of this poster are largely based on facts and portray a possible version of the actual events.

  5. #35
    bwilson4web's Avatar
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    Quote Originally Posted by prasmussen View Post
    . . .
    4. You will enjoy the time you spend building the perfect machine but would you rather be flying with those hours? Should we admire your skill as a pilot or marvel at the machine you have designed? It's all good.
    An engineer by training and background, I'm more interested in perfecting the machine. It is an occupational hazard . . . polishing the musket balls. <grins>

    On a serious note, the 320 hours in my old Cherokee 140 were important:
    • Relief from high-pressure job - when I reached the airport boundary, I hung up my work and home cares and totally surrendered to being the safest possible pilot.
    • Managing limitations of old technology - often I was disappointed by the 1964 Cherokee technology.
    • Night VFR - brilliant when it works but easily able to become 'serious' in seconds.
    • Flight Service Station weather reports - most closed at night.
    • Efficiency - 150 hp, fixed pitch prop, burning 8 gallons/hr, and only gets 100 mph. It climbed nicely with a good load but cruise was disappointing.
    • Ignition - dual plugs fouled by 100LL.
    • Electrical power - a generator using a relay voltage regulator that 'steamed' the battery.
    • Carburetor - icing risk, manual mixture, required EGT to properly lean, and secondary, priming gas plumbing.
    • Tube radios - they worked but gosh they burned a lot of power and ran so hot.
    • Too much talk when we needed text - 1976-1980 voice radio, what a waste of bandwidth!
    • ELT, instrument panel, . . . - there is a long list of that many have already been addressed.
    Notice I didn't discuss VOR navigation since I never had a problem keeping on my true course even with a single VOR head. GPS was not available nor electronic maps. But it will be nice to enjoy what for me will be a technological leap.

    As for flying, I'm expecting 3.8 gal/hr with a 600 mile range. If I really wanted to do something 'interesting', I suppose additional tanks in the cargo and passenger areas might add enough range to do a non-stop, transcontinental flight. If the electro-political issues could be worked out, using a series of 2,000 mile hops I should be able to reach the EU to visit their homebuilding shows and return. But that is in the future.

    The one thing I don't want is to deal with a bunch of 'old technology' management issues.

    Bob Wilson
    Last edited by bwilson4web; 05-08-2012 at 02:45 AM.

  6. #36

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    Quote Originally Posted by Frank Giger View Post
    Hey, I did!
    Sorry, Frank, I missed it. You are correct.

    As for complexity (airplanes with speedbrakes), yes it does add a level of complexity ... and look at all the "world's greatest pilots" that have left the gear in the wrong position. But some airplanes have a hard time going down and slowing down at the same time. I would put Bob's airplane in this category.

    Heck, even my Cessna P172D with 40 degrees of flaps was great; one could get it in anywhere. Flaps going from 30 to 40 only added drag. Note: Cessna got rid of the 40 degree flaps because people tried to "missed approach" climb with the airplane in that configuration. Personally, I would have the speed brakes as either "out" or "in" (no intermediate positions).

    Many sailplanes on the other hand replace a throttle handle with a speed brake handle. It works the same way though ... forward for fast (brakes stowed) and aft to slow (boards out). In that case, some kind of speed brake device is required.

    Bottom line: I agree with KISS.

  7. #37
    bwilson4web's Avatar
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    Waking up this morning, I'm reminded of Burt, Dick, and Jeana and their round the world trip. In the beginning, everyone was a 'Burt' financing, fabricating and testing the voyager. Eventually, Dick and Jeana climbed in the Voyager and flew around the world while Burt provided ground support. Even that flight had to deal with technical problems including loss of the wing tips on takeoff yet they pulled it off.

    So it isn't an either build or fly choice but first comes the build and then comes the flying. Like any flight, there is no guarantee that new (or old) technology won't have problems but a through understanding gives us choices.

    Bob Wilson

  8. #38

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    Bob: Well put, as I look above, behind and to my right in my home office to see an autographed picture of the "Voyager". The photo was taken before the flight as both winglets (fuel vents) were still intact.

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