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1 minute ago, RFguy said:

u can edit the post/ delete the post

Done, Apologies. 🥺

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Hi everyone, I recently had an opportunity to fly the Jabiru J230. I had the flaps fully extended, power off and speed about 70 knots on finals, with the trim set fully back. As a part of normal

@anjum_jabiru , 70 kts is a bit hot on finals with full flap isnt it ?  I would have thought more like 65, then 60 late late (nil wind, good condix)    BTW my J230 does not have a pronounced

J230D: my best approach starts with slowing the aircraft on late downwind abeam the threshold. Carby heat on and reduce rpm to 1600, trim back to maintain circuit ht. 84kt 1/2 flap. Turn base and fly

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cheers Ross, I know it was unintentional. the system got messed up.

 

yeah doesnt apply to Jabiru, applies to any plane.

There are many taught techniques.  each has its pros and cons.

 

Try and do a short field  at Jindabyne from the north, by dragging it in , if you get a downdraught, I think  you will end up crashing into the valley wall before the strip.

J230 is a good plane , heaps of power/climb capability for an LSA. 

 

back to the topic... ANJUM,  anyway, I would suggest , in still conditions ,reducing final speed to 60-65 kts ,   otherwise you will use alot of runway with the float, in my opinion anyway.  and not have much margin for Vflap.

 

My instructor  charges me 20c for every meter I am over the book minimum runway usage.

 

 

 

 

 

 

 

 

 

 

Edited by RFguy
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J230D: my best approach starts with slowing the aircraft on late downwind abeam the threshold. Carby heat on and reduce rpm to 1600, trim back to maintain circuit ht. 84kt 1/2 flap. Turn base and fly down to final at 70kt. Fly final at 65kt. When you’re sure you’re in take full flap, maintain 63 to 65kt. Carby heat off at 100ft ish. Power off in the round out.

For touch and go or go around apply full power and use right rudder to maintain the centreline, pushing forward on the controls to counter nose up tendency, accelerate and raise flaps to 1/2 when positive climb felt, trim for climb. It’s best to have full power and full control before changing configuration.

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trim is for desired descent rate  (maybe 500 fpm on final)  for the applied power, usually.

 

Edited by RFguy
changed 'with' to 'for'
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2 hours ago, RossK said:

Basically the POH says to drag it in, low and slow with power. The risk is if the engine quits, you've got no safety margin in airspeed or height.

If you are approaching at 55 kt, with minimum rate of descent, would you also be in the region of reverse command. That is, might your rate of descent increase if you moved the control column forward or backwards? 

 

I agree with your comment, of course. Slow, with. power and hight AOA is tricky. 

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Any 230 I've flown runs out of trim at both ends of the speed envelope. It's not really an issue though  .  As Jabiru say  you don't have much speed margins at slow speed AND I think some might stall above 45 knots. While it's nice to be able to perform a good speed control and touchdown point,  I'm not sure the skills are that relevant to the go around issues, really.  If you need stick forward don't over do it. It's a "milking the Mouse" exercise till you get the normal climb away situation same as an Auster rough strip take off where you get bounced into the air quite slow sometimes, before you want to.  Ground effect is your friend. Nev

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The advice given that 'brakes are the best way to slow the aircraft' is, IMHO, the worst bit of advice ever in respect of achieving a short-field landing.  Go ask a pro how it should be done.

 

Firstly - cutting the power before the roundout will result in you being unable to hold the aircraft up with elevator, causing it to touchdown  ' flat' on all 3 wheels. Then applying hard braking almost ensures that weight goes onto the nosewheel and off the mainwheels - where you hoped to achieve braking.  Not the smartest idea!   This leads to  nosewheel damage, and often leads to loss of directional control. 

 

As to approach speeds, it's very simple.  For standard approaches - use Vso x 1.3   where Vso is the stall speed at the current aircraft weight - not MTOW.   For short-field, why not use 1.1 or 1.15  x  Vso for the approach, but keep rate-of-descent to 500fpm using power.  When you get to know your aircraft, then this allows you to make the last part of the approach in a configuration that allows an abbreviated roundout.

 

The 1st key to landing on short/soft strips is to only use an into strip aim point if the strip is uphill and it's gusty too.  Otherwise, aim to use the best part of the undershoot to flare across.   Then, keep the power ON  -  until you have the nose well & truly above the strip.  This gives you the aerodynamic braking which is very desirable where conditions direct you to not allow the nosewheel down early.  

 

The other operational item that you should consider with any aircraft that you intend to use for short-field work is to ensure the CG is in the 'middle 'ie, so that you don't run out of nose-up trim capacity.  And yes, you should re-trip on approach - it's not hard, and allows you to keep a 'standard' feel in the pitch control.

 

There is a lot of skill needed to do short-field stuff well and safely.  Scaring the horses via the POH isn't the way to build confidence in pilots or your product.

 

happy days,

 

 

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I have been using a different approach for my regular landing. Once abeam the threshold on late downwind, get carb heat out, power to idle, pitch for white arc / 84kt. 1/2 flap, maintain 80kt, turn base. On base, maintain 70kt, trim full back. If profile is  high, full flaps on base, or wait until on final and landing assured. Aim for 65kt over the fence, and then look outside the cockpit to flare and land. A complete glide approach from abeam the runway threshold on late downwind to touch down, unless other traffic in pattern.

 

Only problem with trim full back, is the amount of forward pressure that may be required if EFATO.

Edited by anjum_jabiru
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Trim setting on final is always full back trim, using throttle to adjust attitude only if necessary.

Having said that, I can still stuff it up with the best of them!

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I forgot to mention that regular glide approach in a Jab is not kind to the engine because it gets cooled down too much (air cooled). Leaving that bit of power on enables the engine to maintain a temperature that is better suited to a sudden acceleration, temperature rise, and the increased load of a “go around” or “touch and go” 

When flying behind a Jabiru, more “mechanical sympathy” means better reliability ( be nice). It’s a great engine and, like all others, needs to be understood and operated in an optimum manner.

Full back trim is normally easily overcome as the trim control will move as the controls are pushed forward.

Edited by phantomphixer
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4 minutes ago, anjum_jabiru said:

Is reducing to 2000 rpm more ideal, than taking the power off completely?

2000rpm is what I was taught in the J160, so probably good for the J230 also.

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id reckon 2000 is a bit hot with the big pitch J230 prop.  It is a much coarser prop than a 160.170..  if all the flaps are out, the high drag configuration will take care of needing engine power to stay afloat. 

Edited by RFguy
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Power will stabilise speed better than if you are gliding. In Gusty conditions your power is an active control and like all other controls will be varying when appropriate. . More power requires the glide path be shallower It also energises the tail feathers and makes them more effective.  Without using power your touchdown point will be harder to achieve accurately in rougher conditions. Nev

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The only problem I see when coming in with power is, I will need to extend my downwind and and final legs, as it will stop me from descending fast enough.  In which case, it would take me further away from the runway, meaning there is less chance of making it to the runway if the engine quits. I guess it is a catch 22.

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Most of your flight you won't be able to glide to THAT runway OR the one you departed from. It's a question of choosing best options for your particular situation. I personally consider a lot of engines approaching on idle are far more likely to stop than one on a low power setting is. Powered descents are being considered a good idea in many aircooled engines to prevent piston temps dropping to where there is excess clearance and ring barrelling happens. If you have to go around a warm engine is better than a cold one AND Carb heat won't work IF the muffler and engine are cold. Nev

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I've forgotten what the speeds and engine RPM were landing the 230 but I do remember the 170 which has the same wings with 1/2 flap and 2000 rpm will sit very nicely at 500 fpm down at 70 knots. I think therefore that the 230 will do the same but at 16-1700 rpm. Then on short final reduce rpm & slow to 60 knots over the fence. Fly to the ground & begin flare to stall at a foot or so off the deck. The horn will be blaring as you increase pitch to touchdown on the mains & keep the stick back to reduce nosewheel weight until you are at fast taxi speed. You do not require full flap most of the time. 1/2 works well so it is generally not needed.

 

When I converted from GA I had a tendency to start rounding out as I came over the fence & then just let the aircraft settle. Pipers & Cessnas will almost land themselves using this method but it doesn't work for Ultralights with less inertia.

Edited by kgwilson
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The Jabiru lists the best glide speed of 65kt for the J230. Any ideas, if this is without flaps or with half flaps? In my understanding half flaps increase lift, without increasing much drag, hence half flaps should give you better glide performance. 

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Flaps never increase your lift  drag ratio unless of the negative type, which are fairly rare. If there's a headwind a slower approach speed will mean the headwind operates on the aircraft longer. Bear this in mind if you are without power. and look as though getting there may be in doubt. Ie delay flap extension at all till you are absolutely sure of making it.  Nev

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Take a look at the curves of lift versus drag for various airfoils, and flaps . Lift increases yep , drag increases alot  . The  centre of lift may back  move slightly, assists attitude and visibility, reduces descent airspeed usefully. 

 

On a simulated EP, my flaps never go out until I'm assured. if I need to drop out of the sky fast, I use a slip. Nev you have I think here pointed out some aircraft will do left  or right hand slips more effectively depending on prop etc config.

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No I've never commented on prop direction only X-wind and visibility over the nose .. I have stated that, in my observations, it's rarely done well and is therefore less effective and sometimes dangerous.  Nev

Edited by facthunter
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I always apply roll (aileron )  first, then push the opposite rudder around and iterate with more roll until I get the slip I want and go no further on the rudder once I have hit what appears to be 'max slip'

 

In the  MS flight sim, on one of the cessnas , if I put a boot of right rudder in BEFORE left roll will produce a skid  and spin. 

Edited by RFguy
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Yes get the bank established quickly and stop the nose falling with rudder. Till you run out of it and you are then on the limit .The slower you go (Safety being considered always) , the more steep your approach angle will be and that is the purpose of the exercise. Getting the pitch angle correct  (it's NOT nose down) is the challenge and depending where the pitot head is the  ASI reading will vary. With practice you can do a nice turn towards the lower wing. (Slipping turn) and that is a very nice thing to watch when done well. Till you are very proficient only do the slip till about 200ft AGL.  Nev

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4 hours ago, RFguy said:

Lift increases yep, drag increases a lot.

I think this makes a lot of sense. The reason you apply take-off flaps is not to increase the lift. It is actually to increase the drag, without affecting the lift too much. This gives you a steeper climb path (if there is such a thing), making it appear as though you have a better climb performance. What is actually happening in reality, is that you are able to climb to the desired height, within a lesser horizontal distance travelled (due to the drag created by the take-off flap). 

 

On applying take-off flap in a glide, once again the horizontal distance travelled will reduce (due to the increased drag), without much impact on the lift being generated. Hence your glide distance (horizontal distance travelled) from a given  height will reduce. Thus causing a deterioration in your glide performance!

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