Goolwa Hangar 1: Jabiru 0 30/12/21

[facthunter]

Well surprise.!! I've not had any  problem either but that's not the point. Many use the pedals to rest their feet on and don't think of  the plane getting on one main and the nosewheel. Nosewheel planes should be easier  as the mains are behind the C of G and should touch first and that is inherently directionally stable. Significant transfer of weight to the nosewheel changes all that and makes it even more unstable than  a Tailwheel configuration.. in the 60's when the Chipmunk and Tiger moth were replaced by Cherokee140 and C-172s there was an epidemic of ground loops and tip overs caused by approaching too fast. This is a constant tendency (laziness). Put the effort into pinning your approach speed to the correct figure and it won't happen. "Some for Mum" means eat up runway or land fast.. Nev

[facthunter]

Some of those incidents reflect lack of recency no doubt. IF you're a bit rusty be ready to go around  at the first bounce. If in doubt get an instructor to be there. A tip over in a low wing can be more of an issue than some highwings but you just don't want to be there. at ALL. Nev

[FlyBoy1960]

Why is the Jabiru such a difficult plane to fly?

 

Seems to require above average pilot skills for what is generally a low performance aircraft by comparison with some others.

[turboplanner]

1 minute ago, FlyBoy1960 said:

Why is the Jabiru such a difficult plane to fly?

 

Seems to require above average pilot skills for what is generally a low performance aircraft by comparison with some others.

It doesn't require above average pilot skills, just correct RA training.

 

[RFguy]

Just on numbers- there are alot of them. 

 

As a J230 owner, I have as usual over analysed this one :

Landing- inappropriate airspeed (too high) I think is a issue -

 

 - you need to have the airspeed spot on for the job. Get the airspeed nailed, and landings are quick and short. The J230 has still plenty of elevator authority at stall even at full forward CG config.

 

That beautiful wing is a mixed blessing.  I think that, the landing phase , where the aircraft is in a vulnerable state , may be with too much airspeed - is  extended  - because that wing has very low induced drag, so the drag doesnt increase abruptly at low speeds and  plane doesnt want to land and stay down if the airspeed is too  high.

This might lead to tricky condix in a Xwind where I would, at least in the Brumby carry more airspeed and power into the flare, where I want to fly it onto the ground wing down..  I think the POH speeds for the J230 for benign condix are 5 kts too high. Well it might be OK with lots of runway , but IMO you are in a vulnerable phase floating along the runway a few kts above minimum flying speed in all but benign condix.

 

 

Edited December 31, 2021 by RFguy

[facthunter]

High engine idle speed contributes to the "clean" problem.  The Jabs are just another aeroplane if you keep to the right speeds. Most experienced pilots adapt quite normally. Depends on what  you have become used to. A Gazelle is far less demanding.   An LSA 55 with only one light pilot on board is  quite an exciting ride..Nev

[RFguy]

 

Nev you are right about the idle- My Jab behaved quite dfferently with 850RPM ground idle versus 1000 RPM idle....

I have a hypothesis about these wheel barrows landings..... :

If sailing along the runway a foot above, due to too much airspeed , (which is what happens) there *might* be a tendency to point the nose down to get it on the ground , when very close to the ground.

 

In these excess airspeed conditions, application of elevator to try and increase the flare, as to bring on a bit of drag, and nose up , slow it down etc will  generally generate a balloon unless carefully applied. She will fly off a few kts above stall.

So, the operator needs to either apply that flare oh-so-carefully, but in any case, runway gets chewed up.  And if it is  short strip - well I think a go around is a must.   There there is a puff of headwind, will that will send you up also, more so if again, excessive airspeed.  

 

So, I think that is where the wheel barrow landings might come from - a nose down command very close to the ground , You can  wait (and wait)  in the very gradually increasing  flare (and chew runway) or a go around .

 

 

Edited December 31, 2021 by RFguy

[turboplanner]

10 minutes ago, RFguy said:

I think the POH speeds for the J230 for benign condix are 5 kts too high. Well it might be OK with lots of runway , but IMO you are in a vulnerable phase floating along the runway a few kts above minimum flying speed in all but benign condix.

A lot of non-related comments have crept into the thread, so people are now talking about a variety of issues. If you come in too fast, you'll float longer but otherwise have an uneventful landing unless you get blown across by a crosswind. Long landings always leave you vulnerable to crosswinds for longer, so, as you've done, knowing your speeds is 101.

If for some reason when the float seems too long, you disregard your training and leave the throttle on but try to make it go lower by pushing the stick forward, you've just set yourself up for a bounce/;wheelbarrow.

 

 

[turboplanner]

3 minutes ago, RFguy said:

 

Nev you are right about the idle- My Jab behaved quite dfferently with 850RPM ground idle versus 1000 RPM idle....

I have a hypothesis about these wheel barrows landings..... :

If sailing along the runway a foot above, due to too much airspeed , (which is what happens) there *might* be a tendency to point the nose down to get it on the ground , when very close to the ground.

 

In these excess airspeed conditions, application of elevator to try and increase the flare, as to bring on a bit of drag, and nose up , slow it down etc will  generally generate a balloon unless carefully applied. She will fly off a few kts above stall.

So, the operator needs to either apply that flare oh-so-carefully, but in any case, runway gets chewed up.  And if it is  short strip - well I think a go around is a must.   There there is a puff of headwind, will that will send you up also, more so if again, excessive airspeed.  

 

So, I think that is where the wheel barrow landings might come from - a nose down command very close to the ground , You can  wait (and wait)  in the very gradually increasing  flare (and chew runway) or a go around .

You beat me to it!

3 minutes ago, RFguy said:

 

 

[Blueadventures]

I'm no expert with Jabs and only flown one once with instructor; but have seen where there is a need to have the fitout weight verified correct and add or remove weight in tail.  An example I have seen is a 230 that had no elevator authority at flair flying the correct number.  This was assessed by an experienced Jab pilot who owns and flys a 230.  As he flared he found the nose would not come up at the landing speed.  A check over w&b and weight added to tail area as per Jab specs and flying great now.  The new owner and previous owner were accepting the poor behaviour and landing with extra speed to allow the nose to come up.  OK, maybe; but only if there is plenty of excess runway ahead.  May not be a contributing factor with this one but worth knowing about I believe. Cheers.

[Yenn]

Surely if you land with extra speed to allow the nose to come up, you are not landing, you are practically taking off. You need the nose up to get the speed down, not speed up to get the nose up.

[RFguy]

Maybe read as "push the tail down" ?

[onetrack]

The speed with which the Jab hit the building - after hitting the shed door outrigger - and possibly the water tank as well - appears to me, to indicate LOC after a failed go-around.

 

Perhaps this article below is highly relevant? I know there's major differences between high-wing and low-wing response upon landing, but a PIO is a PIO, regardless of wing position?

 

https://www.gleimaviation.com/2020/01/10/recovering-from-bouncing-porpoising-during-landing/

 

The final report will make for useful reading. I trust the blokes involved make a full recovery, that must have been a very frightening and painful episode for them.

[kgwilson]

Every pilot in the world has bad landings. No-one is perfect. It is not embarrassing to go around. I have gone around heaps. It is the approach that must be right to land well. Whenever I do go around the next time I nail the approach with the correct airspeed, attitude and rate of descent 90% of the time except when there is a severe crosswind or the conditions are gusty. I have had to go around 3 times on a couple of occasions.

 

 

[Yenn]

I didn't look at the video above but it reminded me of when the RAAF did an approach into Gladstone, I saw them wheels down and flaps out and it looked as if the were landing. the airport operator was just about having kittens and then at about 50' they applied full power and went around, directly over the city council office, where a friend of mine worked as a draughtsman. He later told me his brother was one of the crew and they just wanted to say Hullo.

[facthunter]

Your chances of recovering a nosewheel first porpoise are practically NIL.  Chances are your inputs will be out of synch with the oscillations. With a lighty you might have to stay in ground effect to get a safe climb speed established in the go around.

  It's common for the elevator down force to be insufficient to flare the plane if it's nose heavy. The effect is exacerbated when you close the throttle if the propwash blows the elevators. You then  either land fast(er) or have a heavy landing. (Unchecked fast RoD).   Nev

Edited December 31, 2021 by facthunter

[cooperplace]

I took the jab for a flight the other day, hadn't flown in months. My first landing was untidy. Then I practised a side-slip -was too high on a glide approach- and ended up going around: it just didn't look good. I would not point fingers at other pilots: we all make mistakes. Main thing is no-one was hurt. But that 230 might need some buffing before it flies again.

[facthunter]

Recent experience is important. You get rusty. Nev

[alf jessup]

23 hours ago, horsefeathers said:

What is the reasoning behind that? A weaker nosewheel? More sensitive geometry?

A more sensitive geometry alright, they do a yippy vippy dance real quick (160 that is) not sure on the 230 but I’m guessing so..

[horsefeathers]

44 minutes ago, alf jessup said:

A more sensitive geometry alright, they do a yippy vippy dance real quick (160 that is) not sure on the 230 but I’m guessing so..

I must be missing something basic here. I've put over 500 hours on my Jab 160, with (I suppose, 6-700 landings, and I assume the same number of takeoffs), and it has been stable every time. I genuinely  don't understand the comments about the Jab. 

Now, to put that into context, I previously flew a Streak Shadow (you want to talk about understrength nosegear??) and when landing I would religiously keep the nosewheel off the deck till the last possible moment, at which point it would give a quick shake, and the straighten up.

But I have never seen behaviour as described in this thread with my Jab. And sheet, I've made my fair share of mistakes, but intrinsic problems with the Jab?  As Pauline Hanson would say, "Please Explain"

 

I admit that if you land with the nosegear first, you are in for a whole world of hurt. But that is the same for any tricycle aircraft.

 

[turboplanner]

7 minutes ago, horsefeathers said:

 

I admit that if you land with the nosegear first, you are in for a whole world of hurt. But that is the same for any tricycle aircraft.

 

You have to screw up the landing method to produce it; you answered your own question. If you land on the mains and let the aircraft settle itself you’re not going to experience it.

 

 

[APenNameAndThatA]

18 hours ago, RFguy said:

High crosswind (desire for nose on ground early to gain authority ) and bad surface (desire to keep nosewheel light)  are opposing requirements and I have not practiced nor encountered those requirements yet. 

any comments ?

 

Agree Turbs, and finals and landing in the J230 without anything much in the rear  is usually done with full back trim.  at least in my bird... landing and flare is  full stick back with two pax. 

It would take a bit weight in the back (due to wing posiiton is over the back) to change that.  stick is held back until nose lowers on its own as airspeed decays once mains are down. at least in benign  (nil Xwind ) condix

 

 

 

 

 

Nosewheels aren’t for landing, they’re only for taxiing. (I have a massive 160 hrs. So, Im just repeating something memorable and instructive I heard.)

[APenNameAndThatA]

The best thing to do when landing is to try not to land. Prevents a lot of problems with nose wheels. 

[peterg]

8 hours ago, horsefeathers said:

I genuinely  don't understand the comments about the Jab. 

I have flown the J120, 160, 170 & 230 and have not experienced any type specific control problem similar to some described above. I have flown many other types in GA, RA-Aus & GFA and have experienced type specific peculiarities. The J170 requires a bit of skill to avoid float. The J230 may be the same due to wing similarities but I have not experienced it.

 

An observation - I know a L2 who specialises in Jabirus and he has undertaken wheel alignment correction on a few. That said, it is a maintenance item that is often overlooked and many types probably have an issue but whether it affects handling adversely is not proven to my knowledge.

 

Some of the above comments are unhelpful, unproven and not evidence based - reeks a bit of "Jab Bashing" which I had hoped had died a natural. 

 

Comments from those that have no or little type experience, those that haven't flown anything for a loooong time and those that feel the uncontrolled need to comment on absolutely every item raised on this Forum can be misleading.

 

Personally, I prefer the comments from the "bush lawyers" as I usually get a good laugh.

 

 

[turboplanner]

1 hour ago, peterg said:

I have flown the J120, 160, 170 & 230 and have not experienced any type specific control problem similar to some described above. I have flown many other types in GA, RA-Aus & GFA and have experienced type specific peculiarities. The J170 requires a bit of skill to avoid float. The J230 may be the same due to wing similarities but I have not experienced it.

 

An observation - I know a L2 who specialises in Jabirus and he has undertaken wheel alignment correction on a few. That said, it is a maintenance item that is often overlooked and many types probably have an issue but whether it affects handling adversely is not proven to my knowledge.

 

Some of the above comments are unhelpful, unproven and not evidence based - reeks a bit of "Jab Bashing" which I had hoped had died a natural. 

 

Comments from those that have no or little type experience, those that haven't flown anything for a loooong time and those that feel the uncontrolled need to comment on absolutely every item raised on this Forum can be misleading.

 

Personally, I prefer the comments from the "bush lawyers" as I usually get a good laugh.

 

 

If you are searching for the truth you can go directly to the Accidents section on the RAA site, and I'd suggest scrolling through from around  2007 to the two cases listed for November 2021, and you will have an unbiased, non Jab Bashing, non bush lawyer version of how many runway excursions, where they occurred, how they finished up and what make and model of aircraft was involved.

 

The thread has drifted with some people referring to completely different subjects, and this just happens; it doesn't imply any link with excursions, but these claims are also easily searchable from the same database.