J230 Short field landings

[compsci]

I realize that there was a thread on this topic in 2008, but maybe there is now more experience with landing the Jabiru J230.

 

I make normal (and very good) landings with a final approach speed of 65 knots with 20 to 30 degrees of flaps. However, I am having difficulty landing a J230 on fields less than 2500 feet. I would appreciate advice that included final approach speeds and flap setting, etc.

 

I have been told by instructors (with no Jabiru experience) to use some power with high pitch on final. In essence drag it in.

 

 

[petetheprinta]

That seems a lot of runway for a 230, do you use that distance because you touch down well past the threshold, or does it just take a long time for you to pull up. The 230 I fly lands comfortably in 1200 to 1500 feet approach speeds and flaps as per yours. Are you rounding out too high and using up runway by "floating"?

 

 

[jetjr]

Hi Compsci,

 

Im no expert or instructor but any power will see Jab going faster and less likely to land ie longer. Make approach with full flap, nil power and 65kts over the fence sounds about right. Need to bleed off speed just prior to touchdown though and this means getting timing right. In a short field setup this means being slower by the time the end of the runway is under you

 

Trick is to get final turn in correct height and location so you touch down @ close to stall speed on the piano keys. I do use a little power if I think Im not going to make runway but try to keep it off.

 

The concept of power on landings is a GA approach where aircraft tend to stop flying more quickly and sink is faster. Jabirus are light and slippery tend to keep flying without much effort

 

 

[Camel]

I realize that there was a thread on this topic in 2008, but maybe there is now more experience with landing the Jabiru J230.I make normal (and very good) landings with a final approach speed of 65 knots with 20 to 30 degrees of flaps. However, I am having difficulty landing a J230 on fields less than 2500 feet. I would appreciate advice that included final approach speeds and flap setting, etc.

 

I have been told by instructors (with no Jabiru experience) to use some power with high pitch on final. In essence drag it in.

I fly a J230 and am able to land short with the technique you were told by instructors which is correct and sometime referred to as hanging off the prop, you do your approach normal at 65 with full flap, this will always depend on conditions, when you round out as you come close, slow down and add power with a higher nose attitude but not to gain height but to keep the speed slower, this will depend on conditions, when you pull the power off it will go down quick so get close to the ground and slowly pull the power, depending on nose attitude you will not need to flare. I would think you should be able to halve your distance easily. I am very careful with the J230 at low speed as aileron control at low speeds is very ordinary so speed is very dependant on conditions. I would say do not attempt short landing with crosswind until you are very comfortable.

 

I use a 1500 foot runway on occassions and find it very easy but a very experienced friend with a J230 was not keen to try it but after I pushed him he said it was no problem, so I can understand your position as I think if you find an instructor with J230 experience that can land short you will be fine.

 

I use this technique in a C172 and a 172 can land very short in fact short enough that you won't get out.

 

 

[facthunter]

A short landing needs a minimum speed at just before the flare, and you must not waste runway. To get it this precise, you must use power and would ideally have a moderate amount of power on till the "short" flare is commenced and then cut the power just before the wheels touch. Quite a few 6 cyl jabs have the idle revs set too high and they float too far. They keep on flying if there is any power left on. I've seen pilots who regularly cut(turn off) the engines at flare to stop this effect. This means that a go round is not possible but you have to make your choice, and at wheel contact you should not need to go round in normal circumstances. You can't do it in a glider anyhow. Nev

 

 

[David Isaac]

I don't fly Jabs, but Nev has described a proper short field approach. Short field approach speed is typically 1.3 x VSo (VSo is Stall speed with maximum flap) and using a powered approach, anything less than full flap is not a short field approach and neither is a glide approach a short field approach. Short field technique is short field technique whether GA or RA.

 

Power is used to maintain your aiming point (touch down point) at the minimum speed of 1.3 x VSo. The proper technique is to get all the flap out early in the final and get the power right back to get to your minimum approach speed as early as possible and maintain your speed with attitude (trimming helps) and use small amounts of power to maintain your aiming point. Get all this stable as early as possible on final and fly down the approach slope maintaining precise speed control to the aiming flare point, pull power at the flare and touchdown (getting that bit right will determine how much you float or sink), hold the nose off and use maximum braking with the mains on the ground to use the minimum runway. With aircarft with big flaps the flap drag may mean you need a fair bit of power on approach to make your aiming point. Speed above your minimum approach speed for short field will have you consuming much more runway ... the correct minimum speed is the key.

 

As Nev and Camel have said the power is pulled just before settling as there is typically very little flare and hold off when the speed is at minimum. However, I have heard (and Camel has confirmed) that Jabiru control effect is very poor at minimum speed, so you would need to exercise care and take advice from experience J230 flyers or instructors such as Camel. As Nev has said if the engine idle speed is too high the float will be significantly extended.

 

 

[facthunter]

There is always more to an explanation of this sort of thing. The power may actually have to be increased at the flare If a sink has established that is excessive. You are not carrying any excess speed. You are not coming in high over the fence( every bit of available runway should be used), so in this situation you need to be ready to put a bit( or a burst) of power on, but if you overdo it the whole approach is wasted as you end up being faster than you need to be. That is why I suggest don't take the power off till you are SURE you don't need it. Nev

 

 

[bushpilot]

We have 2 J230s that we hire out.. When doing conversions or check flights we demo short field - with low / flat approach at about 2000 RPM and 60kts over the keys; then back to idle (needs to be below 1000 RPM at idle). The ground affect is minimal and we can pull up within 200 m in nil wind. (Don't try this at home.. Do it with an instructor first; each has their own technique.. :)

 

 

[Wynand]

compsci:

 

Some good advice posted above.

 

I'm still puzzled why you find 2500ft fields a bit tight. What altitudes are you flying at (other than Chicago)?

 

Perhaps the best advice, above, is to check your idle rpm. My motor idles quite happily at 800rpm (static), showing about 1000 rpm in the hold-off.

 

I always use full flap for all landings, even cross wind conditions. Some Jab drivers will advise otherwise, and I'm not arguing.

 

My field elevation is 1800ft and I regularly vacate at the taxiway to my hangar, 900ft after the runway "numbers". I flare over the numbers and probably float at least 200ft before touch-down, so my rollout must be about 700ft. This is without "dragging it in".

 

Chris Stott: 200m sounds about right for a proper short field technique (at low altitudes, light load).

 

 

[frank marriott]

My J230 Flight Manual - short field. 55kts

 

 

[David Isaac]

My J230 Flight Manual - short field. 55kts

Thanks Frank, That was always going to be the next obvious question. If that is what the manufacturer says, then used with the correct short field technique, that is the speed and 5 knots less will make a hell of a difference to the landing distance required.

My suggestion is get some proper instruction with someone who knows the proper short field technique.

 

Regards

 

 

[Wynand]

Bushpilot: I like your website. Nice fleet of Jabs you have. Looking at the specs of the J230 and also at Frank's comment, I realise that you guys are talking J230 at MAUW of 600kg. The 55kt approach speed stated as opposed to to the 65kt called for by my J430 (700kg) POH will make a big difference.

 

The opening poster (compsci) also approaches at 65kt and finds he uses too much runway. What does the US version of the J230 POH call for?

 

And, why use anything less than full flap extension?

 

 

[facthunter]

The indicated speed you use depends on.. 1 Your weight 2 The wind gradient/shear. 3 how much power you have on 4 the gusting nature of the wind.

 

No-one can just give a speed without qualifying it. With a precautionary you are using the power to regulate your speed and flight path. Essentially you are on the low edge of a safe speed so if it gets lower you have to respond with power, quickly. This is quite an advanced precise manoeuver and should be practiced with a competant instructor until it is natural for you to fly that way (in those particular circumstances). For people who have become used to full glide approaches it takes quite a bit of learning sometimes. The aim is to get it nicely and safely ( even if a little firmly) on the ground close to the upwind boundary at the slowest safe speed, so then you can brake hard or whatever you want to do. Nev

 

 

[Guest Andys@coffs]

....... so then you can brake hard or whatever you want to do. Nev

This is a jabiru we are talking about brake and hard should not be used in a sentance in that order but rather the reverse " Its hard to brake" would be more accurate......or perhaps "when braking hard its more likly that you'll break the brake" but then you knew that cause we've talked about it before......

 

Perhaps more seriously if the short field landing will require serious application of brake to stop before the fence or gully then unless you have an after market braking solution you should plan an alternate.

 

Andy

 

P.S I agree full flap until the cutout stops the motor......Drag is good for shortfield landings, the more the better. In fact (joke) have you considered you and the passenger opening the door early on final as an air brake as well. On the checklist add "Doors 30"

 

 

[Geoff]

Have used that technique in the J160 before Andy

 

 

[frank marriott]

"P.S I agree full flap until the cutout stops the motor....."

 

Andy

 

My my comment is only about a fully servicabe aircraft and if you can't get full flap at 83 kts then there is a problem with the flap extension system. If the

 

cutout you referred to happens within the white arc then it needs to be addressed. I can get full flap at the top of the white arc if I am a bit hot/high.

 

As with any aircraft if a problem exists then you make the suitable decision i.e. flapless approach - not to min airfield.

 

Consistant hard application of breaks will result in break fade but intermittent hard breaking will work better in my limited experience [especially on a tar surface]

 

FrankM

 

 

[frank marriott]

Ref Chris's post

 

I agree with his speeds and idle rpm and hiring to people with limited time on type it is better to be consersative.

 

In my experience the published numbers do work. Try inventing your own speeds in an engine out situation in a twin at AUW - the dead engine will only take you to the crash site.

 

Try a PARTIAL engine failure (say max of 2000 rpm on t/off in a J230) and if you are not at book numbers of 65kts then your VSI will be negative but at 65 you can get a positive indication and allow you to return to the airfield instead of landing straight ahead in a paddock.

 

Don' t take my word for it - try it.

 

FrankM

 

 

[Guest Andys@coffs]

Frank

 

my comment about cuttout is simply that theflaps extend until the microswitch is engaged which prevents the motor drivinf further, not that anything is wrong, just that the only way you know youve got to the end of the travel is that the motor stops...The cutout im talking about is fully as designed and intended, not an indication of a fault....

 

The brakes are what they are, they arent great and you plan accordingly......

 

andy

 

Have used that technique in the J160 before Andy

I'd worry about asymetric operation......wonder what that'd do:amazon:

Andy

 

 

[frank marriott]

Andy

 

I obviously misread the intent of your post re flaps - Flap position indicator?

 

FrankM

 

 

[facthunter]

Assy flap would be dificult to control unless you retract to where the other is quickly. I don't think there are any control standards set for RAAus planes. Nev

 

 

[ianboag]

Reminds me of when I was learning to handle my J200. Quite simple - you could slow down or you could descend. Doing both at the same time was a bit tricky :-)