Jacobson Flair

[APenNameAndThatA]

Hi All

 

I have accumulated about 5 hrs in the Foxbat and need to learn how land. (I had about 25 hrs in 172s and 152’s 25 years ago) As you probably know, the Foxbat is pretty STOL. With power on, you can see 0 kts indicated on the Dynon and steam gauge and still be sort of flying (I can’t remember the details. Too busy —— myself, tempting fate with the parachute sitting in the LAME’s shed.)

 

The JF recommends a 3 degree approach. That is equal to about 1:20. So, if you start the final at 500 ft, you will be at 10 000 ft from the threshold. (2 NM is 12 000 ft. 10 000 ft is about 3km.) (I can see where 10 000 ft is on Google maps.) That is a long way out. Too far? Circuits too big? 

 

The Foxbat is at 50 kts on final. That equates to 5000 ft in exactly a minute. (At 60 kts you would go 1 MN in 1 minute.) That equates to descent at 250 fpm. Too slow?

 

The glide ratio of the Foxbat is 11:1, so the JF puts one out of gliding distance. Too risky?

 

If you do a glide approach at 50 kts and 10:1, you descend at 500 fpm and about 6 degrees. 

 

Also the JF recommends that you adjust speed with throttle and rate of descent with elevator. It seems to me that you could adopt the aiming components of the JF without adopting that bit of it. True?

 

The JF says that the traditional way of controlling descent and speed relies on secondary effects. I don’t care. In Cessnas it certainly worked. Also, if you got too low and added power, then you add energy and don’t risk stalling. In Cessnas, the pitch up that accompanied the increased power automatically meant you gained height, rather than speed, with added throttle, as far as I remember.

 

I imagine that you could rework the JF maths for a 6 degree approach and keep the other elements. True? 

 

As a less important point, I am told to turn onto base with the threshold 45 degrees behind me. If I fly downwind ½ to 1 NM from the runway, that will change.

 

I fly out of Archerfield. When I was at the Gold Coast all those years ago, I preferred to come in a little shallower than 3 degrees according to the red and white lights. I have no clue if I approached too fast. No such lights at YBAF yet. 

 

If the final is supposed to be stable by 500 ft, then my final should probably start at 600 ft. Too, a 15 degree bank turn at 65 kts has a radius of 1400 feet. 

 

 

[turboplanner]

Get a good instructor

 

 

[old man emu]

You seem to be overthinking this whole thing. Forget trying to do mental arithmetic in the circuit. Landing is all visual, just like driving a car to the airfield. You don't do any arithmetic while you are driving, so, with experience, you land by instinct.

 

The important thing is to fly a neat, rectangular circuit. To do this at your training field, have your instructor help you identify the reference points.

 

The important ones are:

 

1. The point on the horizon that you fly to so that you are close and parallel to the runway on the downwind leg.
    
    
   
2. The sight picture over your left shoulder when you are 45 degrees off the end of the runway.
    
    
   
3. The point on the horizon that you aim for to fly base leg at 90 degrees to the end of the runway.
    
    
   
4. The sight picture  of the point where you begin your descending left turn onto finals. 
    
    
   

 

 

Keep your eyes on the piano keys, numbers or the bare patch at the end of the runway and fly straight at your target. Initiate the descent with elevator and maintain with trim and engine revs. After the descent path has been established by the elevator and trim, leave it alone. If the target seems to be going under the line of sight, reduce power. If the target seems to be going above the line of sight, add power. Hold your nerve and keep flying to the target until you reach the flare point (That's another lesson in recognising the correct sight picture).

 

On the ground, before you begin a session of circuits and bumps, identify any crosswind component in the wind, relative to the direction of landing. If the crosswind is from the right, you will have to keep in mind that your Base leg will have to be extended before the turn to finals. If it is from the left, the Base leg will be shortened. (Also do the same for a destination airfield when you are doing cross-country flying. If you have prepared your circuit entry plan before you leave home, it will be one less task to do when approaching your destination.)

 

Also, start developing the skill to estimate position from visual clues. The best place to start is while you are driving to the airfield. Start estimating how far from an intersection you should start indicating a turn; how far from red traffic lights you should come off the accelerator or start gentle braking. If you do this practice in your car while you are driving your usual routes, you will hone the skill and it will be easier to apply it to circuits and bumps.

 

 

 

[Blueadventures]

Is your 5 hrs under instruction?

 

Have you done flights at Caboolture as they have Foxbats?  

 

I did a couple a flights in a Foxbat A22 and they will get into and out of tight places.

 

What Foxbat are you flying 22 or 32?

 

As tubo says; get good instruction and do the necessary takeoffs and approaches and landings to be be confident and knowledgeable about its performances.

 

Even consider flying in another similar performance aircraft brand to get the feel then convert to the Foxbat.

 

Cheers and look forward to hearing you kicked the goals. Cheers

 

 

[facthunter]

Get an instructor who is fluent in Foxbat and go to a small strip without much traffic  Preferably none, and do many "different" approaches, based on looking at the strip. A STOL plane is VERY affected by winds  and gusts as it has lots of "extra"lift if you get a small airspeed increase.  A minimum size Foxbat circuit us very small. What you are reading will only confuse you as it has no relevance to your operation, whatever. Nev

 

 

[Soleair]

 JF recommends that you adjust speed with throttle and rate of descent with elevator.

I was taught to adjust speed with elevator and rate of descent with throttle.

 

Bruce

 

 

[turboplanner]

I was taught to adjust speed with elevator and rate of descent with throttle.

Bruce

You had a good instructor, after that you have to do something very unnatural not to land on the mains with the nose up off the ground so you can allow  it to lower at a much slower speed.

 

You're unlikely  to write off a nose wheel.

 

What Pen is talking about is point and shoot which takes you into wheel barrowing, bouncing territory, snapping wheel legs and blaming RA for flimsy legs. These aircraft are not jet fighters and don't respond well to those techniques.

 

 

[M61A1]

Please take note of the warning at the start of these clips, and Turbo's advice of "get a good instructor", especially if you actually intend on using the STOL capabilities of your aircraft, if not, just keep flying your 3° approach.

 

 

 

 

 

[frank marriott]

Short answer, you will not learn to fly off the internet, talk to your instructor is the best advice you will get on line particularly in the student stage.

 

 

[Downunder]

Don't fly a Foxbat at 3 degree circuits. They will take forever at 50 kts on final (important if you are creating a bottleneck for others in the circuit and those waiting to take off) and you will not be able glide to the strip if the engine fails. 

 

Unlike GA and other slippery aircraft, you will not gain speed if coming in steeper. The light weight and aerodynamics of a "brick" make that happen.

 

At 3 degrees, that would be "on the power" for sure.

 

Where I like it on final, is just sitting on 50 kts and the throttle just off idle. I don't know what angle that is and don't care. But it is far far greater than 3 or 5 degrees.

 

Being just off idle allows the option of increasing power or DECREASING power..... 

 

Make sure lowest static idle on the ground is quite low( 1650/1700). 1800 static or higher and it will want to keep flying and will be difficult to get the power down on final.

 

This does make a significant difference. I'm getting about 2100/2200 rpm on final.  

 

I generally use one stage of flap on takeoff and base/final. The main reason is that in a go-around situation I'm already set for flap. 

 

Your widest circuits should be the maximum distance you can glide to the strip from circuit height. If any instructor told me otherwise, I would find a new instructor.

 

My life is MY responsibility. ....

 

600 hrs on type.

 

What Foxbat are you flying 22 or 32?

The 22 is the Foxbat. The 32 is the Vixen......

 

 

[Geoff13]

Hi Pen

 

I learned in a Foxbat at Caboolture and have about 200 hours in one now. 

 

There are some very good and very experienced Foxbat instructors up there.

 

If you are flying 3 degrees at Archerfield in a Foxbat, then you are going to be a world of pain if the noise stops.

 

Many have already said get a good instructor, I would add to that get a good instructor who knows your aircraft.

 

In the Foxbat if you can't glide to the strip from wherever you are in the circuit then I would be very worried. That simple fact almost forbids a 3 degree approach.

 

 

[Kyle Communications]

Get a instructor.....I doubt any decent instructor...certainly the ones that I know would ever be teaching you that flying a low energy aircraft like a foxbat...unless your flying a jet

 

 

[frank marriott]

What does JF stand for?

 

 

[facthunter]

 The name of this post.  It goes back about 30years and was a "suggested" way  by an individual pilot of "judging" landings in commercial jets.. Read and believe my last para of #5 ...Please. Nev

 

 

[old man emu]

Here's a paper describing the Jacobson Flair: https://www.jacobsonflare.com/wp-content/uploads/2015/02/1988-01-aa-aircrew-bulletin-article-optimised.pdf

 

Be sure to read and understand the caveats expressed in the editor's comments (italicized text at the beginning). 

 

 

[frank marriott]

 The name of this post.  It goes back about 30years and was a "suggested" way  by an individual pilot of "judging" landings in commercial jets.. Read and believe my last para of #5 ...Please. Nev

Should have realised, I was thinking in terms of the POH/flightmanual etc.

 

 

[facthunter]

  NO two landings are exactly the same. There's more variation with U/L's as the wind effect is more  as a % of approach speed. and the aircraft have less inertia. You should also adjust the (air)speed you use " over the fence " for ACTUAL weight , gusts, sink rate crosswinds, power on/off etc.. Your flare rate varies also. If you are quite slow the flare will be more abrupt  to arrest the sink rate while you still have flying speed and a stall margin. If you are (too)fast you reduce the RATE of the flare to wash off the excess speed and avoid landing on the nosewheel. That uses up runway so should be allowed for  in your consideration to Go Around if the runway length is marginal. Nev

 

 

[old man emu]

I wonder if part of the problem is that of being timid with putting the plane down on the aiming point. Should a pilot develop a mindset that says, " Who's controlling this plane? Me or Mother Nature. I've decided on a landing point. That's where I'm going to put this plane on the ground, and I am going to make the plane do it."

 

 

[dsam]

The U/L instructor should also cover off the value of sideslipping, especially when clearing obstacles near the threshold.

 

 

[APenNameAndThatA]

Is your 5 hrs under instruction?

Have you done flights at Caboolture as they have Foxbats?  

 

I did a couple a flights in a Foxbat A22 and they will get into and out of tight places.

 

What Foxbat are you flying 22 or 32?

 

As tubo says; get good instruction and do the necessary takeoffs and approaches and landings to be be confident and knowledgeable about its performances.

 

Even consider flying in another similar performance aircraft brand to get the feel then convert to the Foxbat.

 

Cheers and look forward to hearing you kicked the goals. Cheers

Thank you for the kind words. I am at Archerfield and have only ever flown with my instructor. The Foxbat is an A22LS; the slow one. 

 

 

[APenNameAndThatA]

Don't fly a Foxbat at 3 degree circuits. They will take forever at 50 kts on final (important if you are creating a bottleneck for others in the circuit and those waiting to take off) and you will not be able glide to the strip if the engine fails. 

Unlike GA and other slippery aircraft, you will not gain speed if coming in steeper. The light weight and aerodynamics of a "brick" make that happen.

 

At 3 degrees, that would be "on the power" for sure.

 

Where I like it on final, is just sitting on 50 kts and the throttle just off idle. I don't know what angle that is and don't care. But it is far far greater than 3 or 5 degrees.

 

Being just off idle allows the option of increasing power or DECREASING power..... 

 

Make sure lowest static idle on the ground is quite low( 1650/1700). 1800 static or higher and it will want to keep flying and will be difficult to get the power down on final.

 

This does make a significant difference. I'm getting about 2100/2200 rpm on final.  

 

I generally use one stage of flap on takeoff and base/final. The main reason is that in a go-around situation I'm already set for flap. 

 

Your widest circuits should be the maximum distance you can glide to the strip from circuit height. If any instructor told me otherwise, I would find a new instructor.

 

My life is MY responsibility. ....

 

600 hrs on type.

 

The 22 is the Foxbat. The 32 is the Vixen......

Cool. What sort of plane do you fly? 

 

 

[APenNameAndThatA]

Get an instructor who is fluent in Foxbat and go to a small strip without much traffic  Preferably none, and do many "different" approaches, based on looking at the strip. A STOL plane is VERY affected by winds  and gusts as it has lots of "extra"lift if you get a small airspeed increase.  A minimum size Foxbat circuit us very small. What you are reading will only confuse you as it has no relevance to your operation, whatever. Nev

Hi Nev. Have you ever tried using the Jacobson flair? Getting the information costs some money, and you probs land quite okay already, so I would understand if you have not. 

 

 

[facthunter]

It was available to me fully at the time free.. I am comfortable with a Foxbat and stand by my advice that where you are going won't help you at all. It will possibly  and most likely confuse the issue for you. Don't Just take MY word for it. Get flying with a person fluent in Foxbat and that type of plane and show it to him/her and see what they think of the Jacobsen flair...  Confusion is the LAST thing you need when flying and particularly when landing a plane. I contend a Foxbat is considerably different from a  more conventional plane  especially when you have excess speed. near the ground. I'm not going to go into some on line lesson here. That's a silly thing to indulge in as it's irresponsible being a very poor and inadequate way to communicate the vagaries of landing a plane . Pilots don't all do it the same way. You can't do it by numbers as there's too many variables.. The discussion on throttle /speed and pitch/speed  can be unhelpful also  as it's BOTH at times  unless you are gliding. Same as crab or wing down. It's BOTH if you want it to be depending on the situation.. Fly the "B" thing and forget silly numbers. A plane is never on rails. It's in a moving air mass generally. Nev

 

 

[old man emu]

Hi All

The JF recommends a 3 degree approach. That is equal to about 1:20. So, if you start the final at 500 ft, you will be at 10 000 ft from the threshold. (2 NM is 12 000 ft. 10 000 ft is about 3km.) (I can see where 10 000 ft is on Google maps.) That is a long way out. Too far? Circuits too big? 

 

The Foxbat is at 50 kts on final. That equates to 5000 ft in exactly a minute. (At 60 kts you would go 1 MN in 1 minute.) That equates to descent at 250 fpm. Too slow?

 

The glide ratio of the Foxbat is 11:1, so the JF puts one out of gliding distance. Too risky?

 

If you do a glide approach at 50 kts and 10:1, you descend at 500 fpm and about 6 degrees. 

Just doing some simple trigonometry.

 

If an aircraft is at 500' AGL and flies a constant descent angle of 3 degrees, then, in still air, it will travel 9540' before it contacts the ground.

 

TAN 3 = OPP/ADJ = 500/x

 

x . TAN 3 = 500

 

x = 500/TAN 3

 

x = 500/0.05240778

 

x = 9540' (1.57 nm)

 

If you are flying a circuit that puts your aircraft 1.57 nm from the threshold at the Base/Finals intersection, you are just nicely placed. If your aircraft was at 500' AGL,  and 1.57nm from the threshold, then with a still air ground speed of 50 kts, it would take [1.57/50] = 1.8 minutes to descend 500'. That's a rate of 277 fpm.  If, under the same conditions, you did a 500 fpm descent, your airspeed would be 94 kts. 

 

Airspeed on Finals.

 

You have made a mistake here. You have confused Indicated Airspeed with Ground speed.

 

Your airplane needs to have the speed of the air over the wings and control surfaces to be 50 kts for best controlability. However, that 50 kts does not necessarily relate to speed over the ground. You could be trying to land into a 50 knot direct headwind, and the thing will never get onto the ground.  Your IAS would be 50 kts, but your ground speed would be zero knots. The 50 kts approach speed is the still air approach speed.

 

(We could go on about IAS -v- TAS. As I write this, Camden air temp is 39C;  QNH 1009.6; Density Altitude at 500' AGL is 3435' and 50 kts IAS is 53 kts TAS)

 

Glide Ratio.

 

Your glide ratio is 11:1. That's one foot drop for every 11 feet horizontal.

 

TAN X = OPP/ADJ

 

TAN X = 1/11

 

TAN X = 0.0909

 

X = 5.1 degrees

 

From 500 ' AGL

 

TAN 5.1 = OPP/ADJ

 

TAN 5.1 = 500/X

 

X . TAN 5.1 = 500

 

X = 500/TAN 5.1

 

X = 500/ 0.0909

 

X = 5500 ft 

 

5500 ft = 0.9 nm.

 

You can see that by using Best Angle of Glide, instead of 3 degrees, you halve the distance you have to travel to descend from 500 to the threshold. At 50 kts (still air) ground speed, it will take a smidge over one minute to descend 500 ft. 

 

That's a good reason not to turn your circuits into cross-country excursions. Fly close. You'll get more landings per lesson that way.

 

 

[facthunter]

 OME,  You do USE flaps for the approach and they are very effective so your figures are based on the wrong ones . Also If  true airspeed  equals the Wind velocity you will get to the ground but not move forward at all.. Your ROD  (Flapped) will be at least  twice the stated 11:1 glide angle rate which will be close to best rate. with a clean aircraft.. ROD ( average) from any height gives a time in the air figure for you.

 

   The "normal"glideslope whether by ILS or  a visual slope indicator (VASIS) is 3,000 feet height (above the aerodrome) at 10 miles to touchdown. Even in still air  a flapped gliding approach in a Foxbat will be much steeper than that. As far as being stabilized at 500' that's excessive  and it was only 400' for a B727 which has lots of inertia, and lots of things to do, whereas a Foxbat has very little inertia and a very slow approach speed which you wouldn't want to apply at 500 feet as you would hold up all the other traffic. and make life more difficult for yourself. Nev