Roger Lee Posted July 16, 2016 Report Share Posted July 16, 2016 I was taught both since 1980. I know it isn't new, but few talk about it or even give it consideration. Newton's law may also explain why 15 is effective. As air hits the dam caused by the flap there in turn adds some back pressure and more upward force. I do believe it is both theories at work and not just a single one. Come on Eddie. I know you lived during Newton's time because when you were here you told me you were old so chime in here. I know you're just chewing your tongue off trying not to comment. Never say things like you're old. It could come back and haunt you. p.s. Nah Tom you aren't old. I know ED and I are only a couple months apart and I think we are both older than you. Link to comment Share on other sites More sharing options...
Tom Baker Posted July 16, 2016 Report Share Posted July 16, 2016 I was taught both since 1980. I know it isn't new, but few talk about it or even give it consideration. Newton's law may also explain why 15 is effective. It certainly explains why 15 flaps has more drag than 0 flaps. While I may not be older, I'm not some wet behind the ears newby either. I'm not much on self promotion , but I would be happy to provide a bio if you want. Link to comment Share on other sites More sharing options...
Tom Baker Posted July 16, 2016 Report Share Posted July 16, 2016 Roger, I had a student this morning , so I conducted a test. I did 2 take offs back to back. I measured time to climb to 500 feet AGL. One take off was with 15° flaps, and the other 0° flaps. Now the big question for you. Which one took longer to climb to 500 feet AGL? I will post results after you have had a chance to answer. Edited to add: time was measured from a standing stop, with full power applied prior to brake release. Link to comment Share on other sites More sharing options...
Ed Cesnalis Posted July 16, 2016 Author Report Share Posted July 16, 2016 I know, I know, I know [recent grad of Fast Eddie's over night school of advanced aerodynamics] The configuration that reached 500' AGL last was the dirty one. Link to comment Share on other sites More sharing options...
Tom Baker Posted July 16, 2016 Report Share Posted July 16, 2016 I know, I know, I know [recent grad of Fast Eddie's over night school of advanced aerodynamics] The configuration that reached 500' AGL last was the dirty one. I'm not saying you should reconsider, but something to think about is the airplane with 15° flaps did get off the ground quicker, so it had more time to climb. I also edited my first post to explain the timing method. Link to comment Share on other sites More sharing options...
Ed Cesnalis Posted July 16, 2016 Author Report Share Posted July 16, 2016 Trick question! Didn't know when time to climb begins. With your method and a student its possible the zero flaps take off had a late rotation. Question for you Tom: If you time from take off does the result change? Link to comment Share on other sites More sharing options...
Roger Lee Posted July 16, 2016 Report Share Posted July 16, 2016 Hi Tom, If this debate is all about who wins at take off at the end of the runway then there is no debate because zero flaps will get there sooner than 15, but the zero guy will be lower. I did the same thing this morning with a weight of 1420 lbs. Full fuel and two big boys. I don't care which one gets to the end of the runway faster just which one gets me higher in a shorter distance. Getting there faster serves no purpose and is less safe than having more altitude at the end of the runway and less ground speed and less time on the ground with that higher speed. The OAT was 90F and DA was approx. 4800'-4900'. I started my rotation at 45 knots with 15 and let is rise to 60 knots for the climb out. I saw 235F in climb up to my cruise altitude, but stabilised and 221-225F in cruise at 90F and 5200 rpm. All perfectly normal. At the end of a 6500' runway I was higher with 15 flaps over zero flaps by about 150'. The zero flaps got me to the end of the runway faster which I didn't care about. I still would like to know why someone would care if they get to the end of the runway or just past it faster? At zero flaps I had a higher take off roll speed and a longer on the ground. With 15 I lifted off sooner and with a lower ground speed, but I see no advantage in racing there and giving up valuable and possibly life saving altitude. Now the guys who absolutely abhor high speeds on the ground because they have to land at full stall then that higher ground speed must drive them nuts or their argument about extra ground speed handling is toast. Link to comment Share on other sites More sharing options...
Tom Baker Posted July 16, 2016 Report Share Posted July 16, 2016 Trick question! Didn't know when time to climb begins. With your method and a student its possible the zero flaps take off had a late rotation. Question for you Tom: If you time from take off does the result change? Yes they would. I was flying the airplane the student who is an engineer was timing. Link to comment Share on other sites More sharing options...
Tom Baker Posted July 16, 2016 Report Share Posted July 16, 2016 Hi Tom, If this debate is all about who wins at take off at the end of the runway then there is no debate because zero flaps will get there sooner than 15, but the zero guy will be lower. I did the same thing this morning with a weight of 1420 lbs. Full fuel and two big boys. I don't care which one gets to the end of the runway faster just which one gets me higher in a shorter distance. Getting there faster serves no purpose and is less safe than having more altitude at the end of the runway and less ground speed and less time on the ground with that higher speed. The OAT was 90F and DA was approx. 4800'-4900'. I started my rotation at 45 knots with 15 and let is rise to 60 knots for the climb out. I saw 235F in climb up to my cruise altitude, but stabilised and 221-225F in cruise at 90F and 5200 rpm. All perfectly normal. At the end of a 6500' runway I was higher with 15 flaps over zero flaps by about 150'. The zero flaps got me to the end of the runway faster which I didn't care about. I still would like to know why someone would care if they get to the end of the runway or just past it faster? At zero flaps I had a higher take off roll speed and a longer on the ground. With 15 I lifted off sooner and with a lower ground speed, but I see no advantage in racing there and giving up valuable and possibly life saving altitude. Now the guys who absolutely abhor high speeds on the ground because they have to land at full stall then that higher ground speed must drive them nuts or their argument about extra ground speed handling is toast. Life saving altitude is the whole point. I agree it shouldn't be about who gets to the end of the runway the fastest. Altitude is life. So the question remains which configuration reached 500 feet AGL sooner? What if you didn't have a 6500 foot runway? What if it was 1500 foot long and surrounded by swamp? Since safety comes with altitude what is going to get you the most altitude in the shortest period of time? Link to comment Share on other sites More sharing options...
Roger Lee Posted July 16, 2016 Report Share Posted July 16, 2016 When I fly formation at take off (which I didn't do today, but usually do 80% of the time) and I'm in 15 (normal for me) and the other CT is in zero I always get off the ground sooner and climb off to the side just a tad because they tend to be lower than me. Speed wise we are the same until we get out past the runway and then he'll be pulling ahead because he's in zero flaps. If I'm solo and they are two up I have to pull back throttle or I overtake them. If they are two up and I'm solo I may be 100-200' above them at the end of 1.5 straight out (that includes the runway length). The only time the zero CT leaves the ground same time as I do is when we are both solo and because I'm fairly heavy and they may be only 180 lbs they get off the same time as I do. I also never leave the ground right at stall speeds where some are rotating at 40 I tend to keep it on the ground until I see 45-50. So when we all start to compare notes no two pilots are exactly the same in takeoff technique. That part said it all works and is within any takeoff spec. It just boils down to personal preference. Some dump 15 flaps right away after lift off and I wait until I'm at a safe altitude before making any adjustments. Just the way I was taught and it made sense. p.s. I would never use zero flaps on a 1500' runway. Too short and you pass the point of no return too fast. Link to comment Share on other sites More sharing options...
FastEddieB Posted July 16, 2016 Report Share Posted July 16, 2016 I did the same thing this morning with a weight of 1420 lbs. I just have to ask... ...was that a typo? Link to comment Share on other sites More sharing options...
Roger Lee Posted July 16, 2016 Report Share Posted July 16, 2016 Nope. I knew I could suck you back into this conversation. Link to comment Share on other sites More sharing options...
Tom Baker Posted July 16, 2016 Report Share Posted July 16, 2016 Roger, you have made 2 lengthy post saying how you do things, but you have yet to answer my question. I did 2 take offs back to back. I measured time to climb to 500 feet AGL from a standing stop full power and release the brakes. One take off was with 15° flaps, and the other 0° flaps. Now the big question for you. Which one took longer to climb to 500 feet AGL? I'm talking the same airplane and pilot minutes apart, using published climb speeds. Link to comment Share on other sites More sharing options...
Doug G. Posted July 16, 2016 Report Share Posted July 16, 2016 Why the games? Why don't you just tell us. It would be interesting to know. Link to comment Share on other sites More sharing options...
FastEddieB Posted July 16, 2016 Report Share Posted July 16, 2016 Hint: "The Socratic method, also known as maieutics, method of elenchus, elenctic method, or Socratic debate, is named after the classical Greek philosopher Socrates. It is a form of inquiry and discussion between individuals, based on asking and answering questions to stimulate critical thinking and to illuminate ideas." Link to comment Share on other sites More sharing options...
Tom Baker Posted July 17, 2016 Report Share Posted July 17, 2016 Why the games? Why don't you just tell us. It would be interesting to know. I will tell in due time. If you need an answer any sooner you can replicate the test in you airplane. I next time I will add a climb to 1000 feet AGL. I also have a couple other test I would like to try. Link to comment Share on other sites More sharing options...
Doug G. Posted July 17, 2016 Report Share Posted July 17, 2016 I am laid up with sciatica. Today would have been a beautiful day for flying. Yes, Eddie, I know what the Socratic Method is. I have used it a great deal in teaching. However, once the students don't respond the discussion was usually much more productive by working from the known to the unknown to the known by providing the starting point. My favorite question was always, "What does this mean?" A question that has served me well as a student of aviation and a variety of other things. Link to comment Share on other sites More sharing options...
Tom Baker Posted July 17, 2016 Report Share Posted July 17, 2016 Since the question was directed at Roger, I thought I would give him a chance to answer. Link to comment Share on other sites More sharing options...
GravityKnight Posted July 17, 2016 Report Share Posted July 17, 2016 I did 2 take offs back to back. I measured time to climb to 500 feet AGL from a standing stop full power and release the brakes. One take off was with 15° flaps, and the other 0° flaps. Now the big question for you. Which one took longer to climb to 500 feet AGL? My aplogies if it was posted before, but what was the config/weight/DA etc. Reason being....at 6200ft, with a 10k+ DA on a hot day, with passenger/fuel etc., you don't want to even bother trying to take off with 0 flaps in a CT. Especially if runway length is at all questionable. Unless you really enjoy driving down the runway for what seems like eternity. Which config in this scenario clears the 50ft obstacle on a short runway. Of course this is a different scenario than what was posted in comparing climbs to 500ft. So not trying to find fault in your findings, just wondering what the current conditions are where you performed the testing. In my opinion, which is just some guy who doesn't even fly a CT anymore.. it seems the best thing to take away from this thread is that there are different ways to best tackle different situations.. and knowing where/when to apply what configuration/tactic is important and it really is good to share experiences and pose questions and challenges to seek the best results for a given situation. Link to comment Share on other sites More sharing options...
Roger Lee Posted July 17, 2016 Report Share Posted July 17, 2016 Hi Tom, I did answer in post 182. I got to 500' in a shorter distance than the zero flaps. By the time I got to the end of the runway I was at least 100+ feet higher than zero. Before the zero flap setting was ever off the ground I was climbing. If memory serves in 15 I was climbing at 550 at that DA and at zero only 400 at that weight. Link to comment Share on other sites More sharing options...
Tom Baker Posted July 17, 2016 Report Share Posted July 17, 2016 " Hi Tom, I did answer in post 182. I got to 500' in a shorter distance than the zero flaps. By the time I got to the end of the runway I was at least 100+ feet higher than zero. Before the zero flap setting was ever off the ground I was climbing. If memory serves in 15 I was climbing at 550 at that DA and at zero only 400 at that weight. Roger, first off you stated results of what you did, and not the answer to my question. You are measuring how high in regard to distance not time. I don't think anyone will argue that the airplane will climb at a steeper angle with 15° flaps. It is because of this steeper angle that you like many other pilots are letting the illusion flaw your thinking. Yes you reach a higher altitude in a shorter distance, but that is only important if you have an obstacle clear. If you are trying to get, "life saving altitude", shouldn't you be concerned with how quickly you get there, and not where you are when you get there? Here is a slightly exaggerated example. Airplane #1 takes off with 15° flaps and climbs to 1,000 feet AGL. He reaches 1,000 feet just as he is passing the end of the runway and it took exactly 2 minutes to reach that point. Airplane #2 takes off with 0° flaps and climbs to 1,000 feet. He reaches 1,000 feet well past the end of the runway, but it only takes 1 minute 30 seconds. Which airplane got to the safe altitude sooner? Link to comment Share on other sites More sharing options...
FastEddieB Posted July 17, 2016 Report Share Posted July 17, 2016 I am laid up with sciatica.I empathize. After roughly 10 years symptom free, a while back I had a six week back episode that was nearly crippling. Cleared up eventually with Prednisone and muscle relaxant. Scary part is nothing in particular brought it on, making it kinda like a Sword of Damocles hanging over my head. Yes, Eddie, I know what the Socratic Method is. I have used it a great deal in teaching. However, once the students don't respond the discussion was usually much more productive by working from the known to the unknown to the known by providing the starting point. My favorite question was always, "What does this mean?" A question that has served me well as a student of aviation and a variety of other things.Good for you! I think that was the original intent of the query, but it does not seem to be very fruitful. I've pretty much given up trying to convince anyone about the original thread topic - I've already made the best case I possibly can. Link to comment Share on other sites More sharing options...
Tom Baker Posted July 17, 2016 Report Share Posted July 17, 2016 So in the results of my test I was measuring in time, not where I was in relationship to the runway. I was a little surprised that in both cases I reached 500 feet AGL in 59 seconds. As Roger reported it did take longer to get off the ground with 0° flaps, which means there was less time to climb. Based on that the rate of climb is definitely better with 0° flaps. Climbing to any altitude beyond 500 feet you would have a definite advantage using 0° flaps. When I transitioned to the CT 9 years ago I too was taught to use 15° flaps for take off, and I continue to use and teach that to this day. For me it is because I like the feel of the airplane better. I will likely still teach it this way, because for the short distance the increased time to climb at the reduced rate will equal out with the shorter time to climb at the higher rate. The thing to remember is that once you are past that cross over, 0° flaps will give you more altitude in less time than 15° flaps. Link to comment Share on other sites More sharing options...
Tom Baker Posted July 17, 2016 Report Share Posted July 17, 2016 My aplogies if it was posted before, but what was the config/weight/DA etc. I was close to gross weight, but don't have an exact number. DA as reported by the AWOS was around 2000 feet. Field elevation was 500 MSL with climb to 1,000 MSL. Link to comment Share on other sites More sharing options...
Roger Lee Posted July 17, 2016 Report Share Posted July 17, 2016 I only use 15 flaps for take off to a safe altitude before changing to zero flaps and for landings. My safe altitude before changing things is usually 400-500 ft. I do agree that once switched to zero at my safe altitude zero will climb faster, but I also have more speed there. You're still speeding up on the runway and up to the end of the runway. I'm going back out Monday or Tuesday and I'll play a little more and get some numbers. When I'm at 10K or higher or I need to climb better to clear some Mnts. at a lower altitude I may use zero to get faster climb over -6. Hi Tom, I fully agree. "As Roger reported it did take longer to get off the ground with 0° flaps, which means there was less time to climb. Climbing to any altitude beyond 500 feet you would have a definite advantage using 0° flaps." Link to comment Share on other sites More sharing options...
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