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The Jacobson Flare


Rodney

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I have always had trouble with landing.   One day I'd grease it on and then the next day bounce it in.   Didn't matter what airplane I flew.  In all my years of flying I could never find a method by which I could consistently, repeatedly perform really good landings.   And no instructor I have ever flown with could tell me how.   It was the old joke of "There are three rules to making consistently good landings - unfortunately no one knows what they are."   Well now I know what the rules are - they do exist in a clear easy to understand mathematical model that everyone can apply. - No - you don't need your calculator on final!

Full disclosure here - I'm a Kitfox 7 pilot, but I like hanging around your space cause there is just a lot of good information here.  Especially enjoy soaking up all the wisdom Roger has on the Rotax engine.  Went to the Page Fly-in several years back and my wife and I had a great time.

 I flew my Kitfox for five years as a nose-gear airplane, but just recently converted it to a taildragger with big tires.   I had to do something to learn how to land a tail dragger without  continually bouncing down the runway.   It's embarrassing when the guys at the airport get out their lawn chairs - pop a few beers and start taking bets on how many times your going to bounce on landing - or when the inevitable ground loop will happen.   Until I learned this method - I will admit I put on a pretty good show.   

I talked to most of the tailwheel pilots around my airport - talked to one of the pro pilots that fly a Beech C90 for medivac - he also has a Whitman Tailwind - but none of them really helped me.  So I started searching books and the internet.   I finally found this YouTube video - 

 
www.youtube.com/watch?v=cv3ZSHjt8fs
 
The gentleman is a retired airline pilot from Australia.   In the video, he discusses the concept of the method - but does not tell you actually how to do it.  There is an app that can be downloaded to your Iphone or Ipad that goes into all the detail of how to perform the Jacobson Flare.  I think it was about $40 - or so.   It works.  It''s the best money I have ever spent   Believe it or not - it gives you a mathematically based procedure that will work on any airplane - from a LSA to an Airbus 380.   In fact, there is a video of a dude landing a 380 - and you absolutely cannot tell when the airplane's landing gear touches the concrete.    It's the most perfect landing I've ever seen.   
 
I'm passing this information on because it has made a huge difference in my landings.   I don't even worry about my peripheral vision, which at 72 has deteriorated quite a bit.  I don't need it anymore.   I now have a concrete set of rules to apply to landing an airplane.  No guessing.  
 
 I have no financial interest here - just an interest in passing along to other pilots a technique that will actually work for you just like it works for me.     I really find it so strange that I have never heard of this before now, never read it in any magazine nor have run into any individual that pointed me to this technique.   
 
Be prepared to change how you think about landing.  No more "Elevator controls airspeed and throttle controls rate of decent."    That will get you to the runway - but it won't do anything to help you know when to flare.   With the Jacobson Flare - you will know exactly when too flare and how to finish the landing.   Be prepared to spend a few hours practicing.  It's hard to break old habits, but after a few hours of practice, you get it - and it just becomes natural.    I was out this afternoon practicing crosswind landings.   After about the third TnG, I realized I wasn't even consciously applying correction for the crosswind  -  as long as I concentrated on applying the technique - the correction just seemed to be automatic.  I'm also discovering that as I learn to control the energy of the airplane - I am finding out I can pick out where on the runway I want to land.    I picked out the numbers as a target - and landed the airplane and stopped with easy braking well before I hit the thousand foot marker.   I wasn't really trying to do a short field landing - it just kinda happened.   
 
For those of you that are struggling with landings - please try this.  I would love to hear back from you and see if it has helped you as much as it did me.
 
Regards
Rodney 
 
 
 
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7 hours ago, Rodney said:

Be prepared to change how you think about landing.  No more "Elevator controls airspeed and throttle controls rate of decent."

Hey Rodney,  A few observations, I've only quickly skimmed through the YouTube video.  The landing clip around :22 is what caught my eye, holding an aiming point as a constant fixed non-moving spot on the windshield, maintaining this with flight controls (primarily elevator, but aileron / rudder for any crosswind correction also), and airspeed is maintained by throttle, is the process I was taught and employ.

With the CT being such a minimal flare event (close to ground) this aiming location is the numbers on standard long runways, and short landings moves it closer before the runway, maybe as this visual shows.

image.png.8d2abf0f0ab8966f513c2562b042e871.png

 

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20 minutes ago, GrassStripFlyBoy said:

holding an aiming point as a constant fixed non-moving spot on the windshield, maintaining this with flight controls (primarily elevator, but aileron / rudder for any crosswind correction also), and airspeed is maintained by throttle, is the process I was taught and employ.

I was never taught this, however it is how I fly.

 

21 minutes ago, GrassStripFlyBoy said:

the CT being such a minimal flare event (close to ground)

I like how you put this.  Its nice to be on my speed numbers when I arrive at this flare event but extra speed can be bled off quickly without balooning if you have the feel.

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The problem with landings is not that people don't know principles on how to land or miss on some secret "fool-proof system" but rather the fact that this can be highly unpredictable process with many outside variables that need to managed via interdependent inputs.
In other words, it is a complex process that needs constant attention and management - something that comes with experience rather than discovering a magical secret sauce.

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Warmi - this is not magic - it is mathematics.   Of course you still have to fly the airplane and account for all the variables on landing.  

Just from my own experience, in 50 years of flying - no one ever told me or taught me exactly how to manage the flair.    Mostly it was hold off and hope.    I too was taught to use an aiming point to get to the runway.  But that only got me to the runway - it does not give one a precise method of knowing when and how to flare.   As Mr. Jacobson said - all the books etc tell you what to do - but not how to do it.    

Ed  -  Your photos are just awesome.   Wish I hand a eye for photography like you do.  It must be a gift.

I know there are lots of you guys that are not having any challenge in flaring and gently meeting the runway.   

My only goal here is to pass along, to those of you that are having trouble in flaring and meeting the runway - a precise method that has really helped me.   Obviously, if your not experiencing any problems, you don't need any help or education in this area. 

For the rest of us - this is a valuable educational aid.

Regards

Rodney

 

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Rodney, I went to Stick and Rudder in Idaho this summer to learn tailwheel and the Kitfox.  Me and my buddy Kin are building one and it should be done end of winter.

Paul Leadabrand was my instructor and he basically taught me this method.  Great experience.  Since that course my landings have dramatically improved and my wife is much happier to fly with me!

By the way, I'm in Tulsa and fly to Durant regularly to visit my buddy Kin.  Maybe we can meet up sometime and visit.

Grew up in Atoka/Tushka and flew to Atoka twice in the last week to visit family.

 

Tom

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20 minutes ago, Rodney said:

to those of you that are having trouble in flaring and meeting the runway

At the risk of sounding arrogant, I am the very best Flight Design "land-er" at my home airport... ; )

(the only one based there).  My airport is well known for its shear, the FBO Manager, a gruff dude who is an excellent pilot said to me  "I hate Light Sports, if I were you I would land at least a 1/3 of the way down the runway... on both ends because of our windshear".   Our airport sits up on a table top at 420 feet MSL, we are next to the coast and north of us are hills... so the wind, even on "nice" days can be tricky.  We have two wind socks and a US Flag on the field, I have seen when all 3 are pointing in different directions many times..

I am totally intrigued and will follow up Rodney, thanks for posting.

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Rodney - I watched the entire video and the ideas he presented, in terms of determining height above the runway by distance from the target point, the timed flare, etc. are interesting. I looked up the app but there’s not much information there about what it does, and it’s a bit pricey.  Can you tell us in general terms what the app does?  

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John -   Thank you for your question.   We all land our airplanes using visual "clues" or observations from the cockpit.   In the app, Mr Jacobson goes into very specific detail on the flare maneuver.     However, he does start with the approach to the runway.   He tells you in very specific terms what are the visual clues you need to employ and use on the approach to the runway.   And I mean it is specific - there is no ambiguity.   When it gets to the flare - he does two things.   One - using visual references - he tells you exactly when to start the flare, and then Two -  he tells you specific visual clues to execute the rate of the flare.    If your interested - he goes into the math and principles behind the technique - but most important:  what are the visual clues - when to flare - and the visual clues used during the flare.   

The thing that has helped me the most is knowing exactly when to flare and exactly what to do in the next 4-6 seconds from the flare to the touchdown.  

In my first post I apologize if I sounded so excited - but this has been a total eureka moment for me in my flying journey.   I imagine if Coronado had discovered the Seven Cities of Gold he would have gotten down off his horse n whooped and hollered.   I feel the same way.  

AGLyme - I used to fly in Arizona.  Between Phoenix and Flagstaff there is an airport at Sedona.   Locally - it's called the USS Sedona - like an aircraft carrier.  It is located right on top of a mesa with steep drops on each end of the runway.  I think your airport manager is very wise in telling you to land 1/3 of the way down the runway.   I know a guy that - after they landed - a gust flipped their Cherokee over.

Okent - let's get together.  Are you building a nose or taildragger?    I'm just a few minutes from Durant and would love to see your airplane.  We can get together and go flying too.   Would love to give you and your buddy some more Kitfox time before you fly your bird.  My email is:  Stinson97502@gmail.com    

Regards

Rodney  

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  • 2 years later...

This is an interesting thread that I never had seen.

I wanted to put out some things here. The whole "pitch for airspeed throttle for altitude" is a teaching tool that isn't supposed to have each thing considered in complete isolation, it's a generalization to describe what the aircraft is doing aerodynamically. It's a teaching tool for theory for climbs and descents, but it's often not taught correctly for landings because there's one more factor: you're trying to aim for a target.

When you're doing a landing and you use throttle to speed up as some people have said, what you are also doing is controlling pitch. You're not doing one or the other entirely on its own. If you were just using throttle, you would climb away from the runway as the nose pitches up to hold speed.

It is impossible to use pitch or throttle alone to change airspeed and maintain the same aimpoint.

So if we break it down and you pay attention to your inputs, you'll see that when you throttle up you're also making subtle pitch movements and you might not be realizing it. You're still pitching for airspeed and using throttle to control your gradient, it just might not appear that way at first glance.

I will look at the video later, but @GrassStripFlyBoy holding a spot like that is called the zone of action in the military. It's the spot that will neither move under or away from you. It's a very useful tool for emergency landings too and someday I'll have to make some videos on this stuff.

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All of my landings in the CT are done with full flaps, and I find that if I trim for 60-62 kts with 15 flaps before turning base, it yields 45 kts at full flaps, which is my normal target for short final.  Only one trim adjustment required. Flaps don’t go down fully until fairly late in the approach. On base and final, trim takes care of the airspeed, no pulling or pushing the stick, just using power to hit the aim point.   With a little experimentation, the same method could be adapted for whatever you like in terms of flap setting or approach speed.  This largely takes pitch control out of the equation until over the runway.  FWIW. 

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45 knots on short final? Are you trying to short field every landing, or is your ASI malfunctioning? That speed will stall some CTs with load even with full flaps (no power)

Also, you are controlling pitch with the trim. Whether you push on the stick, use an autopilot, or use the trim, it's still pitch control. That said, it sounds like you just let the nose move when you use your throttle. It would be subtle but it will move.

It will work just fine for smaller adjustments. I also have no issue flying in very windy conditions (15+ knots with gusts) and full flaps should not be used in those conditions and will sometimes take students out in those conditions to really drill home how wind can make things very difficult, and to lay the foundations for them to still get to safety if they're really forced to fly in that kind of stuff. It's not uncommon to have winds change like this while out on a cross country.

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My airplane stalls at about 30 kts indicated with full flaps, so for me 45 gives me a fair margin and very little float during flare.  With gusty conditions, I add a bit but not much. I’m guessing that not all CT’s indicate the same airspeed at stall, and I would suggest that people make sure they know their indicated stall speeds by actually stalling it.  Yes, the nose changes pitch with power change in order to maintain the trimmed speed.  I wouldn’t recommend that people with lower time in the CT land in windy/gusty conditions with full flaps.  For me, though, the lower landing speed is more comfortable because it limits the time spent with wheels on the runway at close to flying speed.  I’m not suggesting that others use these airspeeds, but I thought the trim method might be helpful. Just be sure you don’t inadvertently pull back on the stick when it pitches down. 

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Corey, I think that much of the variation in indicated airspeed on short final reported by CT pilots is due to variability in ASI calibration across the fleet.  So, whenever I see a pilot report their airspeeds (or worse, recommend airspeeds for various maneuvers to other pilots) I make a mental note that "YMMV".  I practice slow flight in the landing configuration at altitude so that I am very familiar with my airplane's indicated airspeed at which it will stall and at which it will fly.  (As I am typing this, I see that John has just made a very similar point.)

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I don't see this kind of variation with the 5 CTLS I work with. They're at most a few knots different, and that includes cross referencing with the round gauges. That's why one of my eyebrows raise when I hear speeds like that.

I can get one to stall at 30 knots but that means I have to have a lot of power in to do it. I usually see stalls around 35-38 knots.

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Mine stalls at 30 at idle power, so apparently there are some differences.  It’s always been this way, so although I’m certain that TAS is higher, I can rely on the indicated speed for control but wouldn’t use the same speeds in a different aircraft.  Back to the trim method again, one of the benefits I see is that airspeed control is automatic in reasonably smooth conditions, so eyes can be out of the cockpit. Again, make sure that stick inputs are aileron only.  

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@Anticept To expand on your very pertinent comment, I was able to retrieve these interesting 2 diagrams (sorry for french) that shows effect of stick or thrust change on speed and vertical path over time. 

1. if changing AOA (stick position) at constant thrust :

A is for Stick Position ; B is for Speed ; C is for vertical path 

image.thumb.png.577c73c2e0b89b2172e50b21bd08559b.png

 

2. if changing thrust at constant AOA (stick position)

A is for Thrust ; B is for Speed ; C is for vertical path 

image.thumb.png.124e03462229d8596911985a6fcc5f34.png

1 remark I translated from the original article from Michel Barry

Between VI and V2, two speeds taken at around 1.3 VSO, we can clearly see an influence of the control stick on the trajectory, but not the one we expected!
In fact, the trajectory at VI is steeper than at V2.
In other words, at constant power, the more you pull back on the stick, the steeper the descent, which seems paradoxical
And if you don't respect the approach speed properly, especially at lower values, you'll be surprised to find that, despite correct pre-display of power, you can't maintain the approach slope at all speeds below speeds below 1.3 VSO.

 

image.thumb.png.ad2a4b2c780e97ffa36e74ca2d0f05c8.png

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3 hours ago, Anticept said:

Question. What's your estimated weight at landing?

If you're a lightweight with 10 gallons of gas in a sub 750 CT, that might make it light enough that the stall speeds can get so low.

I did consider that.  I’ve checked it at near gross weight, and the actual break was as described.  45 kt on short approach in this airplane gives me a few seconds of float, just about the right amount for me, enough to make a comfortable transition without eating up lots of runway.  But again, the main point I was trying to convey was not the approach speeds, just the trim method. BTW, I’m impressed with your ability to raise just one eyebrow.  I don’t have the gene for that.  😁

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Francois: It's because of the lift to drag ratio and L/D max.

https://i.stack.imgur.com/NEFfp.png

 

Basically, when you're at the bottom of the L/Dmax bowl, drag forces are at their lowest, and you get the greatest bang for buck distance. This is where best glide speed lies. If you go up one side of the bowl or the other in speed, you are doing nothing less than shortening your glide distance. Usually approach speeds are on the induced drag side of the slope, relatively close to L/Dmax.

Some aircraft even exhibit a very strange phenomena called the zone of reverse command (ZoRC). That might be related to speeds below 1.3 VS0 that you were talking about. In the ZoRC, it takes substantially more power for a given increase in airspeed, until very suddenly you break through a "wall" and lurch forward, and could even bring back power and as long as you don't cross that barrier, it takes very little throttle to maintain airspeed. It's almost like the lift drag bowl has a tall speed bump in the middle.

Generally, when teaching approaches, we just use a very generalized method of teaching people how to perform the approach. This is all too complex to teach and humans are actually pretty good at approximating things and developing a sense, given enough experience.

@John Vance that's interesting. What year and model? What avionics? Is your static port on the belly reversed? I've seen a couple aircraft out there where the air dam is misaligned, which would have an effect on static pressure and give you a lower airspeed reading.

What power setting are you at during all this? I do know I can get mine to break at ~28 knots full flaps full power during AoA calibrations. I've never tried to see how it would behave between.

Anyways, I don't find any fault with your method. You've refined what works, and what you're doing isn't a concern to me if you're able to handle yourself in a variety of situations. As an instructor, one of the things I like to challenge people to do is to keep yourself adaptable, no telling what circumstances you might encounter and your method is one tool in the toolbox!

That said, I do want to point out one thing: our flight designs go slower than most other airplanes. If you enter a pattern doing that you're going to be causing people to do long downwinds or have to break out to avoid overtaking. Be neighborly too!

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Corey - it’s a 2020 CTLS, Dynon 120/100.  The static port is correctly installed.  I aim for 90kts @ 0 flaps abeam the numbers on downwind, pull power to idle, hold altitude & slow to 80, apply 15 flaps & trim for 60 kts. By then it’s about time to turn base.  60 kts is held until short final, then it’s time to hit the brakes, i.e. apply full flaps.  I do give the stick a little push at that time to avoid ballooning.  My goal is always to leave power at idle, but it doesn’t always work out.  Sometimes a VERY small touch of power helps during flare in windy conditions to give more time to sort things out. I’m aware of other folks in the pattern and do make changes when needed, but this method is rarely an issue.  I’m capable of landing with any flap setting, including -6, just in case of flap failure or other situations.  This is what works best for me after 8 years of trying to get consistent approaches.  I was often either too high or too low on final, and for awhile was even using the slow side of the L/D bucket to increase glide angle rather than slipping (which bothers my wife).  Holding 60 kts from base turn to short final seems to have helped me get more consistent approaches in the CT, and allows reasonable blending with other traffic.

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2 hours ago, John Vance said:

Corey - it’s a 2020 CTLS, Dynon 120/100.  The static port is correctly installed.  I aim for 90kts @ 0 flaps abeam the numbers on downwind, pull power to idle, hold altitude & slow to 80, apply 15 flaps & trim for 60 kts. By then it’s about time to turn base.  60 kts is held until short final, then it’s time to hit the brakes, i.e. apply full flaps.

That's very standard.

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Yes.  But this was in answer to your questions, none of which relate to my original point, which was simply that applying proper trim after chopping power allows you to let the airplane largely take care of pitch inputs through base & final when conditions allow.  The happy coincidence for me is the fact that one trim setting works for both 15 & 35 flap settings. That’s it.  Maybe this will help someone, maybe not.  

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