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Thread: Tail low or tail high - flaps?

  1. #1

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    Tail low or tail high - flaps?

    Dave says a new thread is in order - I agree. One of my favorite subjects.

    We have well-marked pavement, with arrows every 200 feet on takeoff. These new GPS units are uncannily accurate. I'll look for my data, but on hard surface with almost everything held more or less constant, I get better performance with a STOL Cessna 180 through 100 feet with flaps up, tail wheel only an inch off the runway, then pull back at about 50mph. The worst performance was with flaps 20, rotate to level attitude, then pull as soon as level. Most spectacular, and most scary, was flaps 20, three-point, climb at 60 indicated. I wonder if I could have survived a sudden engine stop at 50 feet.

    My performance engineering school said that best climb is attained at minimum drag, and Piper and Cessna modify that by allowing climb at speeds below clean stall with flaps extended. For the Cub and Cessna, I think best performance off of hard surface is flaps up. Soft surface and water is a different situation.

    I know we have done this before, but I think flaps are over-used on climbout. Most pilots think extended flaps increase climb rate.

  2. #2
    Dave Calkins's Avatar
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    Bob, thanks.

    I just finished a set of VG's on a '54 180. At low airspeeds, the a/c feels much more solid, control authority-wise, in every axis (pitch, roll, and yaw) with Micro VG's. This statement is to go with your description of the "..most spectacular, and scary, takeoff...".

    The statement that "... for the Cub and the Cessna, best performance off a hard surface is flaps-up.."............. Not for me. Flaps commanded at the correct moment feel like they're connected to a jack directly lifting the a/c....................for good lift-off performance. After lift-off, I'm not so convinced that flaps help.

    I agree that best climb happens at the most-efficient speed for the airfoil system, which should seem to be the same speed as best-glide speed.

    I'll leave the argument open here for a bit so others can join. Bob, Thanks again for opening a new topic. DAVE

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    SJ's Avatar
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    I think the question is, are you trying to get all three wheels off the ground for a contest, or are you trying to clear the 80' trees staring you in the face?

    I learned a pretty good lesson on a 90 degree day at 4500' in Oregon that you really don't need/want those darn flaps to clear the trees, and that the teensy little baby pinecones I saw way too close up will someday grow up to be big pine cones, you know, 3 or 4 inches high....

    sj
    "Often Mistaken, but Never in Doubt"
    ------------------------------------------

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    Susan was telling me about that takeoff! ...Clyde

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    Steve - you and I - and a lot of true aerodynamic engineers seem to agree: flaps hurt you in the climb. Even best angle climb.

    Flaps are lift, and lift makes you go up? That, along with the kick in the tail, is what makes the average private pilot believe that flaps are good for climbing. But it ain't so - lift is what counteracts gravity, and excess power is what makes the thing climb.

    Flaps shorten the ground roll. You get the required lift at a slower airspeed, but at the expense of drag.

    Best glide is probably around Vy - but best angle up is Vx. You want best angle down only when the field is way below you and straight ahead.

    That's all opinion, of course.

  6. #6
    mvivion's Avatar
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    A lot of mixed metaphors there, guys...

    First, as Steve noted, you have to define "best climb". There are two "best climb" speeds for any aircraft: Best rate of climb (which is indeed generally close to best glide, or best L/D) which affords you the most altitude for the amount of TIME you are climbing. Best Rate is almost always with flaps up, in my experience.

    BEST ANGLE of climb, however, is a whole different deal. Best Angle is the climb configuration that will offer the most altitude gained for every foot over the ground of forward progress. A very different task, and almost always done with flaps deployed.

    Another way to look at this is that the point of best angle is not to maximize climb, but to minimize forward motion while climbing. In that context, yes, flaps do help, by significantly lowering stall speed, and permitting the airplane to be flown at a slower forward speed.

    For example, the Super Cub best angle of climb configuration is full flaps and 45 mph with full power. Go out and try to do better with no flaps, in altitude for forward motion covered, and you'll fail, believe me.

    As to takeoffs, they are so sensitive to pilot technique that I doubt you could ever say much absolutely.

    I'm of the opinion that you'll get the shortest takeoff run with half flaps and tailwheel lightly on the ground in most tailwheel aircraft. In otherwords, flown off pretty much three point, or tail low.

    MTV

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    Quote Originally Posted by mvivion
    A lot of mixed metaphors there, guys...

    I'm of the opinion that you'll get the shortest takeoff run with half flaps and tailwheel lightly on the ground in most tailwheel aircraft. In otherwords, flown off pretty much three point, or tail low.

    MTV
    My experience is limited to Cubs, Pacers and 180/185's but I would have to agree. Our home strip is marked as well and my best departure in the 180 is always with 20 degrees, and a 3-point departure. As far as the climb out, I use 20 degrees (or 10 degrees on later models) until i clear my obstacle.

    One thing interesting to note is that when I went from the stock tailwheel spring and stock 8" tailwheel to the uprgraded spring and XP mods tailwheel...I lost a good 50 feet on average in take off roll. This is just when I 3-point it off. I'm assuming due to the lost AOA. Looks like big main tires are in order.


    I should also note that when I tow gliders in the Agwagon, flaps at zero ALWAYS produces the best rate of climb.

    Bill

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    S2D's Avatar
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    Re: Tail low or tail high - flaps?

    Quote Originally Posted by bob turner
    , I get better performance with a STOL Cessna 180 through 100 feet with flaps up, tail wheel only an inch off the runway, then pull back at about 50mph.
    I think the first thing you have to do is define performance
    I may be wrong but that probably won't stop me from arguing about it.

  9. #9
    jnorris's Avatar
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    Quote Originally Posted by mvivion
    I'm of the opinion that you'll get the shortest takeoff run with half flaps and tailwheel lightly on the ground in most tailwheel aircraft. In otherwords, flown off pretty much three point, or tail low.
    I'm with MTV and Bill on this one. When it comes to getting up and over those trees at the end of the short strip, half flaps (20 degrees in the C180) and a very tail-low takeoff run will get you up and out the quickest.

    Once the obstacles are cleared, then no flaps and best rate will get you to altitude in the least amount of time (but not the least distance traveled).

    Works for me anyway!

    Joe

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    I agree with Mike only when the climb speed with flaps is lower than any speed you can attain without flaps. I have found that at recommended speeds for flaps extended Vx in both Cubs and 180s the deck angle is extreme to the point where such climbs are in the realm of emergency procedures. But what I really find is that students extend flaps to 20, rotate the tail up for a long ground roll, lift off at 60 or so, and climb at 70 or more all with flaps extended. That is because the experts have told them that things go better with flaps extended when you go up.

    As far as takeoff performance is concerned, I rank the best performance as that which gives you the highest altitude at a predetermined point, for any given configuration. I get that with tail low and flaps up, except for emergency situations, which I try to avoid on takeoff.

  11. #11
    StewartB
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    For fun...and we're talking about a C-180....

    You're on a slightly sloping beach. The sandy gravel is soft. Your 29" mains are leaving 2" deep tracks, your big tailwheel about the same. There's driftwood and debris within 2' of you track path on both sides, but scattered. There are a couple of drainage depressions you'll be crossing perpendicular to, and some other bumps, too. The wind's blowing about 45* from the left at 15mph. After 400' the surface degrades badly, and at 500' ground gives way to water. There are trees on your left but the horizon to the right is essentially unobstructed.

    What'cha gonna do?

    SB

  12. #12
    cubflier's Avatar
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    When I was practicing for the Valdez Contest I tried just about every sensible configuration imaginable. Much to my disappointment there was not much difference in take-off lengths. In the end it was a toss-up between two styles that provided a benefit.

    The two techniques that provided a perceived benefit were 1) Tail low, full flaps already applied, otherwise the classic 3 point take-off and 2) A variation of tail high with initial setting of 10 degrees and then pull full flaps on lift-off.

    I had planned on doing one of each technique but ended up using the tail high technique both times and oddly enough had identical length take-off rolls.

    In the real world tail high is the technique I use on a regular basis for many reasons and they are as follows:

    1. I'm not tall and need the visibility.

    2. Tail up protects my tail wheel and the tail structure of the aircraft.

    3. Tail up provides better steering on the take off roll.

    4. I use my flaps as a jack to pick the plane as Dave described above.

    5. I rarely if ever climb out with full flaps since any benefit is short lived and results in too much drag at least for my cub anyway.

    As with all techniques I vary what I do per the situation and assure you if I'm in a swamp where you're lucky to get a light cub off in 700-800 feet I will use a much different technique than described above.

    Jerry
    If it looks smooth...it might be

    If it looks rough...it is!!

  13. #13
    Jerry Burr's Avatar
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    Hi Guys. First off I think that Cessnas and Cubs are about as comparable as apples and potatoes. The next problem is stock or modified wings or flaps. And the last is how much power is on tap. I'll stay with the subject of Cubs thank you. A stock wing with modest hp, say 150 will fly off the ground in 3 point or modified 3 point with no flaps in a good distance. That's the procedure that I see some Cub pilots using. Then there is the pop the flaps and jerk the stick crowd. But they usually go to 1/2 or no flaps for climb out. I am from the low power, usually overloaded crowd. I will explain why I do what I do and you can try it. If it doesn't work for you I won't be surprised and you shouldn't use it. My first problem is that I have just short of 200 sqft of wing that is usually at a high AOA when sitting on the ground. If I try to go off in 3 point it's like dragging two large barn doors along with me. The run has to be started with no flap/ails or it would be like dragging the doors plus a plow. So the plan is to get the wing in the best position to accelerate. This is minus 2.5 degrees of AOA or negative lift. Assuming a minimum of wing twist that is the position the wing will accelerate the fastest. The counter argument is usually that the elevator deflected down creates as much drag as the wings would create. Phooey. The AOA at rest is nearly the same and there is a signficant size difference. Anyway as soon as the airplane gets serious about moving the elevators are almost neutral as it is though lifting and is more balancing. The other thing I take into consideration is that in the 3 point attitude you are trying to power or drag the airplane out of a stall into flight. By starting out in flying attitude you can increase the AOA beyond the normal critical AOA for a short bit of time and the airfoil will continue to create lift. A high drag factor to be sure but nothing like the drag of a stalled wing. Remember that in the air at altitude you have gravity assisting your speed in recovery from the stall. Then the flap/ailerons are applied to get you into ground effect, and you just stay there until the flaps are bled off and you have the speed you want for best angle or rate of climb. For best angle that happens very quickly. By having 4 notches of flaps you can select 10deg which produces a significant amount of lift with (very) little drag increase. Which is usually used only for terrain clearance as my next problem is usually oil temp so I try to keep the speed up as soon as possible. Another consideration is tires. They seem to have a terminal velocity on the ground or in grass. The sooner you can get them off terra firma the better you can accelerate. You high power guys don't have to worry about applying flaps too early as much as we low power types do. If I drop them too soon I can use up a terrifying amount of distance. Jerry.

  14. #14
    cubflier's Avatar
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    Jerry,

    I'm curious to know your thoughts on trim position on take-off.

    Specifically for a light loaded minimum fuel take-off contest type of configuration.

    Jerry
    If it looks smooth...it might be

    If it looks rough...it is!!

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    Here is an unrelated performance thought: Suppose you had a full commuter jet, and just discovered that your runway was way too short.

    What do you do - do you hold it on the ground until the other pilot hollers V!, rotate, or do you yank it off like a Cub, climb out below Vmc until you clear the trees, and hope that one of them doesn't quit? Boeing finds minimum unstick by doing approximately that. They literally bang the tail on the runway trying to get airborne.

  16. #16
    Jon B.'s Avatar
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    Quote Originally Posted by bob turner
    Here is an unrelated performance thought: Suppose you had a full commuter jet, and just discovered that your runway was way too short.

    What do you do - do you hold it on the ground until the other pilot hollers V!, rotate, or do you yank it off like a Cub, climb out below Vmc until you clear the trees, and hope that one of them doesn't quit? Boeing finds minimum unstick by doing approximately that. They literally bang the tail on the runway trying to get airborne.
    Geez, Bob, it's a part 135 operation. You go back to the gate and unload passengers 'til you're light enough.

    Were we all taught the wrong techniques in our primary training? I've been led to believe that a short-field take-off and a soft-field take-off were quite different, with the short-field taught as Jerry Burr described it. Get the aircraft moving with low drag, positively rotate and hang on.

    The winners (and all of us losers) at the New Holstein used the tail up - some way up - method. A 130-foot ground roll isn't too shabby.

    The soft-field TO is intended to be draggy, as the idea is to load the wings as quickly as possible, getting light on the wheels. If the field is short and soft, I'm SOL, 'cause I can't get out.

    Jon B.

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    Jerry Burr's Avatar
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    Hi Again. I've spent a lot of time testing the tail high as in how high. And anything above or below negative lift is just unessary drag. As for trim, I never touch it. The long droop ailerons balance the flaps so no trim is needed. One other thing I wasn't going to mention, but will share it because of Jerry's inquiry. I was having trouble trying to break the 40' takeoff barrier. Then I discovered that it took 15 feet to raise the tail. If I raised the tail before the roll I could shave off those 15 feet. Have Fun. Jerry.

  18. #18
    mvivion's Avatar
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    Jerry makes an excellent point in his posts: These techniques may work best in an airplane with a VERY light tail. His point was that comparing Cessna taildraggers and Cubs, or even Scouts and Cubs, or maybe even lardo Cubs with very light Cubs truly is apples to oranges.

    I certainly don't disagree with Jerry's assertions relative to a very light Cub. Try that in a Cessna 185, though, and your results MAY vary. Those heavy tails take a lot, aerodynamically speaking to lift off the ground.

    One point, though, Jerry: when you say "anything above or below negative lift is just unessary drag", am I correct in assuming you mean zero lift, rather than negative lift? In other words, the wing basically parallel to the ground, or slightly higher? The ultimate in "negative lift would be the airplane on its nose. Just asking what you define as "negative lift".

    MTV

  19. #19
    Dave Calkins's Avatar
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    A long one, but read the whole thing!

    I have an answer for StewB's question.

    Jerry's airplane is different from the ones that most of you SuperCubbers are flying.

    I have found that if one breaks ground and leaves it with a positive climb, one will be off shortest. The most-often seen mistake with the "tail high, yank the elevator and flaps, cross your fingers and toungue AND hope"-crowd, is that THE moment THEY choose to fly, may not be the moment the AIRPLANE chooses, and thusly, will often bang the tailwheel and go dribbling down the takeoff zone. That's not a good way to get off short!

    With a tail low takeoff you will get in the air positively every time, no matter what the load, etc. etc. ..........assuming wind and terrain allow this.(My opinon, not to be construed as refuting Jerry Burr!)

    Stewart B.hat'cha gonna do?

    I don't know what "slightly sloping beach" means to you, but I'll bite anyway. Also, 2" deep tracks sounds like a pretty good load, but "sandy gravel is soft" could mean the gravel moves around alot and allows you to sink in, even if light. You're talking about a 400 foot usable surface, so you are obviously not at gross.

    (I'm trying to get a feel for how sloped your beach is and how heavy the a/c is. I'll have to make some assumptions without complete information. Can you say what beach we're at?)

    ................Depending on the beach slope, My worries are:

    1. not turning to the top of the beach
    2. not hitting any wood on the take-off zone

    ....and I'll need rudder authority and visibility over-the-nose for this. So......tail high is winning.

    But, I'm also dealing with only 400 feet for a 180 on a soft surface, so I need to get the wing carrying the load........so....The tail should be low and 20 degrees of flap.

    But what if "slightly sloping beach" means enough beach that the wind will be attempting to lift the uphill wing? I'll need the tail low so the wing, with left roll input to the ailerons, will make some lift. I don't want to come off the ground and drift crosswind into the water if there are waves!

    And what if we could clear some debris nearer to the water where the beach might be firmer and then use THAT as our takeoff zone.

    And, if the water is smooth, are we up to the task of skipping the tires on the water if we run out of takeoff length??

    Sorry, I've added questions.

    DAVE

  20. #20
    Dave Calkins's Avatar
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    A summary for Stewart B.'s question: (which I'd like to hear an answer to from some other 180/185 guys for).

    ........left aileron, tail low, but high enough for ok visibility, 20 degrees.

    Of course, conditions other than how I interpret SB's description, could change everything.

    ......DAVE

  21. #21
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    I trim the nose almost full down for take off. 1 or 2 notches of flap ( i have 4 ). Little forward pressure on the stick and by the time the tail comes up a little back pressure on the stick and apply full flap and it lifts off. Took off in 135' in new Holstien and I think my other 2 take offs were with in 20' of that at 80F so its consistent. Cub weighs 1198 with a 8244 prop. Big thing is not to pull flaps to early.

    If I try starting my take off with the tail up when I release the brakes it falls back on the ground.

  22. #22
    StewartB
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    Dave,

    In my scenario I'd start with 20* flaps and get the tail high as soon as possible to maximize visibility, steering, and to keep from being launched into the air prematurely by the bumps. I'd keep my tail as high as practical until I was ready to commit to flying. After the initial 400' the weight on the mains would be minimal so in this case the runway is probably 500' long. If I thought the last 100' was too soft I'd go to flaps 30*.

    My bigger point was that the techniques used on pavement often don't have much use in the real world.


    SB

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    Jerry Burr's Avatar
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    Hi Mvivion. My mistake Zero lift is correct. Should be minus 2.5 degrees for a clean 35B airfoil, or the horizontal about two inches lower than the trailing edge of the wing.
    Hi Dave. My experience has been that if you wait to break ground with a positive climb you will probably be assured a good second or third place in a competition. As far as knowing when the airplane is ready to fly, a good low speed airspeed will increase that accuracy immensely. No matter if you are taking off downwind, upwind, crosswind the wing experiences the same relative wind as the pitot. In Montana one year I had to adjust my sunglasses for 3 or 4 minutes until the Coke banners all dropped dead, then I could do a minimum speed takeoff without getting blown across the runway. Just use all of the information that's available. Jerry.

  24. #24
    Dave Calkins's Avatar
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    Jerry, how many feet longer than first-place is second or third-place?

    Will a meat-laden Cub know it should fly when Joe-Blow pulls hard on the stick after attempting a "STOL competition" takeoff?

    I know Jerry is in tune with his Cub for STOL comps., but what technique should a grossed-out-Cub pilot use when the atmosphere differs from one day to the next, one ridge-top to one creek-bar, to rain/shine, wind/calm, crossing/tail/straight-on wind, frozen a.m., warm p.m., rock, grass, pea-gravel, wet sand, soft sand, mud,???? What works every time with ZERO guessing.........

    .........POSITIVE climb away from the ground will bring the a/c home every time.......dribbling down the runway from failed pull-timing will have that bird on top of the bushes.........and the pilots' buddies helping him patch it up (if there are buddies around to help).............no thanks for that, unless I'm getting payed for the recovery, thank you!

    I mean this in all respect for Jerry, who has simply stated what works for him in STOL comps.

    I'm also interested in what methods work for Joe-STICK everyday to hunting camp or fishing-bar.

    DAVE

  25. #25
    Jerry Burr's Avatar
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    Hi Dave. Me again. I misread your post. You didn't say positive rate of climb. You said it will come off the ground positively. Well..... to tell you the truth that is the reason I don't ever use the tail low method. It won't come off clean. Many the times I held my breath as I tried to power through the not on the ground / not in the air mode. I was vulnerable to every little bit of turbulence and cross wind that wanted to kick me around. By getting a little speed and making a positive break with rotation from terra firma I just skip through that previously somewhat helpless speed range. In fact in a nasty crosswind I hoist the tail up real high and keep it nailed until I'm good and ready to depart. Most do have a lot more power than I do and can motor through that area. Not meaning to cross you, just more thoughts on the subject. Jerry

  26. #26
    Dave Calkins's Avatar
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    Hey Jerry.

    Yeah, I guess the horsepower is a difference to consider.

    I note in your description that you said you: "...In fact in a nasty crosswind I hoist the tail up real high and keep it nailed until I'm good and ready to depart.."

    That doesn't sound like a STOL, but a "survival" takeoff.....and for good reason.

    As far as tail low and wait, or tail high and yank, I suppose the difference in Horsepuller will lead to a difference in technique.

    Cheers, and goodwill! DAVE

  27. #27
    Jerry Burr's Avatar
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    Boy Dave you're quick. How much between 1st and 2nd. Well last month I lost to Denny Martel's 200+hp experimental Cub by 4 feet. That's less than a hick-up. When I was up there one year a famous Cub pilot took me to the side and says "Listen here sunny, this is how you get a Cub off short" And I have no reason to doubt him. " You pull the Cub back between the trees as far as you can. Then run her up and release the brakes and push forward on the stick and start counting. When the tail comes up start counting again and when you get to the same number rotate and she will come off the ground every time." It doesn't work for me but he had a heck of a lot more Cub time than me, so I wrote it down. Had no idea I would be sharing it on the World Wide Net. Man just get out there and practice. And practice Heavy. Then you won't get stuck in places like Dave suggests. Jerry.

  28. #28
    Dave Calkins's Avatar
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    Yes, practice.

    Practice will help you to know when to pull back on the stick. Or when to let it fly on it's own, or when to pull it in next to the trees and tie it down for the night. That's an option that I thought of giving StewartB. for his scenario, depending on how steep and high the beach was, and if it was a sustained 15 knot wind, and if the tide phase would allow him to wait for a different wind.

    So Jerry, how many horse is the white Cub?? You only gave up 4 feet to Denny?

    What do each of your a/c look like in the current iteration?

    Thanks. DAVE

  29. #29
    S2D's Avatar
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    You get the shortest takeoff by knowing where to place the 2X4.
    I may be wrong but that probably won't stop me from arguing about it.

  30. #30

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    Note to Jon B: I was alluding to a recent event, where it was clear that the pilots ran out of runway way too late to return to the gate. Absolutely, even part 91, if your computations do not yield a survivable event with an engine failure at V1, you do not go.

    Remember Air Florida, where they flew into the Potomac with reduced thrust set? Suppose the mind set was absolutely we must not fly below Vmc? Just a thought.

  31. #31
    Jerry Burr's Avatar
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    stuff

    Hi Dave. On a really good day I have almost 100hp. I got rid of the Piper exhaust (on a field mod no less) and that freed up about 9hp according to my figures. I haven't had a chance to talk to Denny this week. He is drilling wells like mad. Uses the Cub to haul drill rig parts between the islands. With his power and Waynes slat and extended chord flaps plus extended chord droop ailerons he is tough. I never compete in the experimental class because I'm in normal category. But this contest was (different) ran the flower bombing 3 times and no short field landing. Ahh, but that's life. Take Care. Jerry.

  32. #32
    Dave Calkins's Avatar
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    Thanks Jerry. I love hearing about your stuff. Sure would be nice to see you in action in AK. again!!!?

    S2D: 2x4, 4x4, driftlog, dead coyote.............

    PS I ferried a Husky today.....ferried a different one a couple of days ago. Felt pretty nice. My landing technique started with a 'behind the power curve' approach at about 50mph. I got it down to 45mph on final with the VG-equippped Husky, and the feeling was good. I just peeked at the ASI to see what it said, There was no need as there's plenty of feel in it. It's blowing straight down 13 at Hood right now at about 17mph, and the thing was impressive with the help of the wind. I'm guessing about a 40 foot landing. Later I'll ask how long the landing was of a guy who was waiting to take off when I touched down.

    Thanks for your response, Jerry.

  33. #33
    mvivion's Avatar
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    Dave,

    I think one point that your and Jerry's comments make here is that in the various scenarios you presented a few posts back, one can probably conclude that in the "real world" of off airport operations, there probably really is no "Best SINGLE technique" for max takeoff performance.

    I think every situation, every surface, every airplane and every loading may respond better to a slightly, or sometimes a significantly, different technique.

    That was, I believe, Stewart's point, and a valid one.

    MTV

  34. #34
    mvivion's Avatar
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    Dave,

    I think one point that your and Jerry's comments make here is that in the various scenarios you presented a few posts back, one can probably conclude that in the "real world" of off airport operations, there probably really is no "Best SINGLE technique" for max takeoff performance.

    I think every situation, every surface, every airplane and every loading may respond better to a slightly, or sometimes a significantly, different technique.

    That was, I believe, Stewart's point, and a valid one.

    MTV

  35. #35
    Jon B.'s Avatar
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    Quote Originally Posted by bob turner
    Note to Jon B: I was alluding to a recent event, where it was clear that the pilots ran out of runway way too late to return to the gate. Absolutely, even part 91, if your computations do not yield a survivable event with an engine failure at V1, you do not go.

    Remember Air Florida, where they flew into the Potomac with reduced thrust set? Suppose the mind set was absolutely we must not fly below Vmc? Just a thought.
    Oops! I guess you mean the one in Kentucky. That was ugly. They tried to get airborne off a 3500 foot runway. Even their best technique probably was insufficient for that one.

    I though it was ice that brought down the Potomac River flight. It was snowing mightily that day.

    Jon B.

  36. #36
    Jerry Gaston's Avatar
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    Best takeoff performance for me in a C-185 is trim neutral and one notch of flaps. Hang it on the prop. Any more flap just acts as a drag. In talking to Cessna they say the best lift config is one notch of flaps and I think that applies to Super Cubs as well. Full flaps are for landings.
    Another thing I noticed when watching short field take off contest is the guys that try to raise their tails before rolling simple end up dropping the tail when they release the breaks any way so why waste the effort.

  37. #37
    StewartB
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    Specifically for 180/185 guys.....

    Did you ever pay attention to the effort it takes to keep your tail up while rolling out after wheel landing? It's really easy to keep the tail up with 40* of flap. A bit harder at 30*, harder yet at 20*, harder at 10*, and near impossible at 0*. That's precisely why we dump flaps to maintain contact with the ground on short squirrely landings.

    So, go out and find the speed at which you can fast-taxi with the tail up at 0* flaps. Pull flaps. What happens? (You fly.) Heck, just fast taxi to a speed where you feel the plane getting light on it's feet in three point and pull flaps. What happens? (You fly.)

    The effect is the same if you start the drill at 10*, and so on.

    The only reason I don't select full flaps for a normal take-off is that I can get the plane into the air at speeds that are slow enough that it's hard to control the plane, leaving too little safety margin. There are times that such a technique is valuable (soft field), but you'd better not catch any gusts, and you'll need to retract flaps to gain speed.

    I will NEVER hang a Cessna on the prop unless I have no options. If that happens I screwed something up.

    For what it's worth...my normal take-off is tail-up with 20* of flap. Once airborne and clear of obstacles I retract flaps and then reduce power and prop. I use Vx often (64mph). My normal landing is tail-low at 40* flaps.

    SB

  38. #38
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    Last night I went out with the C-180 and tried all the different take off configurations mentioned here. For my plane ('57 C-180 IO-520, 3 blade Hartzel, Sportsman STOL) 20 degrees, trimmed nose down a little, tail up, produced the shortest, best feeling, take off.

    Tried 3 point O flaps, 10 degrees, 20 degrees. Tail high 0 degrees, 10 degrees, 20 degrees. Yanking the flaps on when the tail came up etc., etc.

    Still, the best controllable take off was getting the tail up and rotating. It may be different with different airplanes. I think you need to find what works for you and use it.

    Take care. Crash

  39. #39
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    I agree that both on and off-airport ops will require a complete bag of tricks.

    A 180/185 guy who has impressed me during the time I've known him uses the tail-low method most, and agrees with the others here.....tail-low 20 degrees flaps, let it fly off. Anyway, yeah, whatever you feel most comfortable with.........and to some shorter members, getting the tail up so you can see over the nose is important. But, yes, whatever you're most comfortable with!

    Stewart B. said, about an obviously lightly-loaded 180: "...The only reason I don't select full flaps for a normal take-off is that I can get the plane into the air at speeds that are slow enough that it's hard to control the plane, leaving too little safety margin."......

    .SB.....Can I interest you in a set of MicroVG's?!!!!!!! The VG's give the "margin" back by increasing flight-control surface authority at low speeds in all axes. Really!

    Really! DAVE

  40. #40
    StewartB
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    Dave,

    There's only been one time where I wished I had VGs. Short-ish strip with trees very close on the right, crosswind from the left. I found the plane drifting toward the trees left-wing-high even with full left aileron, full power, and the nose lowered. That's not a good feeling. I learned from that experience, and haven't done it again. (I had lifted off about 100' before the end of the available strip. That 100' would have provided me more penetration speed. I don't leave usable runway in front of me to fly off slow anymore. )

    Thanks for the VG offer but I'll respectfully decline. The Cessna's going dormant again this winter. Maybe next year.

    Have you ever done a full flap take-off in a 180/185? Pretty impressive, huh? A crafty old BFR instructor used to have me demonstrate them, and a few other cool things that most guys would argue a 180 can't do. I miss Tom Wardleigh.

    SB

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