skippydiesel

11 minutes ago, facthunter said:

RPM is not enough . You need a torque figure or a thrust figure as well.   You could be way out. MP might suffice.  Nev

From poor memory (will need to check on next flight) MAP around 22" 

4 hours ago, RFguy said:

skippy , your comment of : " My current Rotax aircraft seems to be delivering about 15 L/hr, 5200 rpm at 130 knots indicated - how would a Jab compare?"

 

Is not valid for this discussion.

 

We're talking about a specific fuel consumption for a specific shaft horsepower (in cruise for total fuel consumption argument ~ 75% ) .

The discussion is aircraft invariant  . 

And no correspondence will be entered into

 

So - for one comment, within many, you refuse to engage - Me thinks that puts all your commentary in doubt😈

I think you will find that Rotax 5-5300 rpm is about 75%  power.

RF ,

Your logical presentation is heading in the right direction however some possible holes (I stand to be corrected):

"Prop spins a bit slower on the Rotax, that's worth a few % in efficiency. The Rotax prop spins a lot slower (a little over 2100 rpm at 75% cruise, to the Jab (guess) around 2700 rpm) and is not only more efficient it tends to be quieter - important in Europe now and in Australia in the future (fly neighbourly)

Rotax torque 128 NM @5000 rpm gives it an advantage in TO/Climb out.

Rotax runs lean in cruise. Jab runs compatratively rich, costing perhaps 5 to 10% in fuel " - My current Rotax aircraft seems to be delivering about 15 L/hr, 5200 rpm at 130 knots indicated - how would a Jab compare?

AT 2000 hours, Rotax has had a gearbox service  @ 1000h maybe about a grand, - 1200 hrs if run on ULP

Both have had two sets of plugs. - will need to check but I think Rotax recomend 200 hr/set of plugs = 10 sets

Both have had 1 set of hoses  - Rotax rubbers replaced every 5 years of service and likely at least twice as much hose involved - must be more costly than Jab

Both have had 40 x  oil and filter changes.  - Rotax recomend an oil change very 100 hrs (when run on ULP) so this would be 20 oil changes, compared with Jab X 80? (at today's prices, this is a difference of about $2,000)

The rotax fuel consumption is worth a bit, at 2000 hours, youve probably put 1 litres more per hour into the 2200  = 2000 litres = $4000 more ! and proportionaly more for the 3300 6 cylinder.$6000. - seems to me your fuel consumption for the Jab is a tad optimistic - More likely up to 5 l/hr difference (could easily be a 10,000L difference or $23K today, for 98 RON).

My feeling is the 2200 you end up costing  about the same as  the rotax, Nice thought

and the 3300 end up costing quite alot more -

but you have a far more powerful engine that can do 115 hp all day. True but this does not take into account the higher torque delivered by the Rotax at 5-5200rpm which I assume means a more efficient prop delivering the same/more thrust at 75% cruise..

Note: I have focused on the Rotax 912ULS , as I have no experience with the 912UL, comparing it with the little I understand of the Jab 3300

2 hours ago, justinjsinclair said:

I completely agree and that’s the whole point. If you are looking at building or buying  an aeroplane or thinking about learning to fly by all means use the web as it it’s a great tool. Agreed But please seek out qualified advice by a LAME, CFI or someone who has real world experience in or on the thing you are looking at.

if someone tells you that something is a bad choice then that’s fine but you really should be asking for facts. The reality is we all tend towards bias, even "LAME, CFI". I absolutely agree with "asking for facts" however, in my limited association with the small aircraft world, it seems to me that bias, in the form of familiarity  unreasoned product loyalty, etc is on a par, if not trumping fact and this observation includes "LAME, CFI".  Confirmation bias is alive & well, reinforced by the retreat into the tribal gatherings, for reassurance/ afformaton. Difference of opinion is met by derision and even aggression.

Dont  trust me either 👍 Good advice but I do own a Gen 4 powered Jab. Happy for anybody to fly it as well.

 

 

14 hours ago, facthunter said:

Skip is it JUST POSSIBLE your last post applies to you?. You are very scathing/dismissive of many other opinions, Nev

14 hours ago, Blueadventures said:

Exact same thought, absolutely agree. 

I do not dismiss other opinions - where I have something to contribute, I do. Scathing - for sure! where such a response is warranted.

Much depends on the logical progression of the writers case - if it doesn't sound right, it possibly isn't. If there are large gaps/omissions, the writer is either poorly informed or so biased he/she is unwilling to acknowledge information that does not support their assertions, alongside those that do ie not a balanced argument.

It is a shame that our debates, so often seem to, degenerate into personal attach.

10 hours ago, justinjsinclair said:

Hey KG, what an awesome post. 
In fact the Jab is nearly 50% cheaper 2200 vs low hp 912 if you add up all the costs in a mature way. SD doesn’t want to put the effort into obtaining the facts but that’s his or her choice.  
Don’t get me wrong, the Rotax is a wonderful bit of kit but now that we are up to $350 hr for a RAA aeroplane dual because the 100’/annual can be $5-7000.00 at LAME rates, I kind of feel a fleet of J160’s is still a great choice for a flying school, particularly if you have a L2 that can maintain the Jabs exactly as per the Jabiru Work pack.

Given that Jabiru is so much cheaper inguess in that case we can probably accept a bit of bracket creep as Jabiru costs increase 😢. 
SD banging on about the top is also a odd thing given that nearly all air cooled engines need work at some stage once they go under that 75 hours per year, having said that the Gen 4 has nikasil bores and the head issues are gone I am betting that the Top overhaul requirement will move as well.

as I said I don’t have a vested interest in Jab other than owning one and maintaining a couple, if anyone wants to pm or call me for further info fee free.

Justin “who identifies as him” 😅

Faith is a wonderful thing. Those that have it, are often blind to any other reality and so happy in their world. 😈

9 hours ago, kgwilson said:

SD you are obviously a Rotax evangelist  Bit overstated. I certainly like my Rotax 9. Had great service from the last and hope to have the same from my new one. and that is your right but when I commented in another thread that I liked the simplicity of the Jabiru engine compared to the complexity of the Rotax 9 series you disputed this. I agree (as always) the Jab is a "simpler" engine but "complex" ?? As a person pretty much raised on small capacity high revving automotive engines, I can't say I agree - probably a perspective/semantic thing.  Complexity for me equates with difficulty in understanding /servicing /maintaining, non of which seem to apply. mentioned that the failure rate of Rotax engines is actually higher News to me. Do you have figures and analysis to back this statement? than for Jabiru engines in Australia in 2023 plus a catastrophic failure in a Sling locally. One off incidents do not indicate a trend. All mechanical devices will fail, the question is how long will a type stay in service ie maintain reliability over time. I have no doubt that Jabs have an will probably continue to improve - then the question is  what is the most cost effective engine (within a hp range)  I thought that would be like a red rag to a bull but no not a peep. I don't care that there are Rotax engines with 2. 3, 4 ,000 hours on them. You should, because length in service, without significant life extending intervention, will impact on the cost per hour to run the engine.Plenty of jab engines make the 2000 hour TBO as well. I note, with a wry smile, that you immediately have the Jab at a lower TBO None of these I would guess are owned by private pilots unless they were purchased from a flying school.

 

The Jab engines restrictions imposed by CASA back in 2014 was pushed by some disgruntled FTF owners who ended up as CASA employees and the numbers originally quoted were way over the top but it led to some pretty nasty comments on this and other sites back in 2014. Nowhere else in the world had any issue with Jab engines at the time.  This seems to be a very unlikly assertion. Tall poppy syndrome alive and well again. Jabiru is easily the most successful aircraft and engine manufacturer Australia has produced. We should be promoting local industry and innovation not deni grating it. What would you suggest? - hide our heads in the sand? in the name of brand and national loyalty? Well there are over 2,000 Jabirus flying around the world, "More than 50,000 engines of the Rotax 912 / 914 series were sold since 1989, resulting in more than 45 million" flight hours" of the fleet half of them in Australia and they are exported to over 30 countries with over 7,000 engines having been produced and installed in all sorts of aircraft and even drones. Yes they are an Australian success story and I so acknowledge however initial purchase cost is a big factor in this, as is the low flight hours/year of many recreational pilots. The low hours means that a 1000 hr overhaul may not happen in the time of the original purchaser (ie of little/no consequence) and may also mean that many are predominantly used in local flying ie concerns about reliability, as part of the purchase decision, are reduced. So if you want to argue that Jab meet a need, I would agree.

 

It costs me about $45.00 to do an oil and filter change every 25 hours, about twice a year. The cost per oil change (Jab/Rotax) is likely to be in the same ballpark - the Jab just has to incur the cost X 4 often. How may private owners fly 100 hours a year?  I agree - see below. Most will still need an oil change annually anyway. How many purchased by private owners are going to make TBO given the low annual hours. Most will be out of time well before they reach TBO. As I said above - if you want to argue that the majority of Jabs will only fly a few hours a year, thats fine and whatever additional costs there may be, then pales into insignificance.

 

Your cost comparisons are irrelevant. All the plumbing has to be replaced at 5 years. The jab engine only has the oil cooler hoses. True! (assuming the water cooled heads conversion has not been done😎) In my case I fly 19/experimental, which means I can minimise my costs by purchasing automotive hoses that equal or better Rotax  specifications . I still have to purchase Rotax carburettor rubbers, so about  x2 the cost of a Jab carb rubber replacement.

I note that my questions/observations have neither been answered or challenged.

It seem a little unbalanced that I can be taken to task over a spelling mistake but when I ask some searching questions/observations regarding statements made, I am somehow "having a go at a few people lately"😈

1 hour ago, Methusala said:

Faux pas (not fopa) gaffe, blunder, indiscretion,impropriety etc. I.E. a mistake which really demands an apology, Similar to addressing me as Donna!!

Thanks for the spelling lesson.

I have made my apology.

6 hours ago, BrendAn said:

You have been having a go at a few people lately. Never noticed it before.  

I have no idea what you are referring to - please elaborate.

How is this" having a go"????

1 hour ago, justinjsinclair said:

That’s ok,  Skippy or what ever your real name is. Tad aggressive 😎
Just like the spelling there is a valid reason for my questions/s
If you can’t get a name spelt correctly and want to sprout anti Jabiru and pro Rotax sentiment that’s fine and it’s your right, just as it’s my right to point out that your (just like mine)  opinions need to be treated with caution. Agreed

i asked you on what basis and education you have to post on the subject. Could not find this question 
Have you built, maintained, flown either of these types. Simple question really ? Never built from scratch. Have done a complete in/out refurb on a composite/fabric and finished off  (intensive 24 months) an all metal homebuilt. I am the sole maintainer.

So many look to these forums to guide them on potential purchases of all RAA style aircraft and that we should all be careful sprouting rubbish that is ill informed and frankly lazy. Is this a generalised comment or are you aiming at me?

We need to be more positive, if someone wants to buy a Drifter, Metroliner or Primary glider we should encourage them and if we are going to poo poo their  idea then we need to make sure we are not hiding behind some pseudonym, drinking almond soy lattes from our tesla on our way to another Microsoft flight sim session where we think a FW190 is easy to fly. (BTW not accusing you of fitting that mould] I agree with having a posative attitude to life in general however when it comes to the purchase of a machine, I advocate for critical analysis (what you seem to infer as negativity) - so many are purchased on the basis of familiarity/brand loyalty/marketing claims and little else.
I know the costs of both Rotax and Jabiru (actually you can add Lycoming, Continental, P&W, Garrett, CFM and RR to that as well) and think both of them are fine engine’s and both have a place in our world. Cost? If we are being absolutely logical, this is made up of Pre Purchase (investigation), Acquisition, Running, Repairs, Insurance, Residue (sale of old) and if being really strict Depreciation (aged brain probably missed one or two). Without a shred of evidence I suggest that Rotax (compared with other similar Hp) will come out as least cost overall.

You are asking me to put in effort to answer questions that you don’t appear to want to put in the effort yourself to answer. If you want me to answer them I am happy to but you will need to pay, happy to invoice you incl GST. Actually not asking you to do anything other than acknowledge that you may have missed a few points in the Jab V Rotax never ending debate
I have no vested interest in Jabiru other than they are a fine company that brings dollars into our country that we all need to pay for our Eectric vehicles, city slickers coffee and pensions. I confess, on a regular basis, to having a love affair with my Rotax 912ULS.🥰

Jabiru Australia tare wonderfully passionate people, they are awesome to deal with and absolutely 100% reliable from a professional point of view. They own their product and employ many Australians. Passion is but a necessary ingredient in the development of any product and its great to hear of a provider receiving such a glowing akolade.
Why we as Aussie’s feel the need to tear them down is quite beyond me. I am so sick of the “Jabiru in the paddock joke” perhaps you might like to see where much of the European technology comes from, might be a nice history lesson for you.

Maaate! Jab make a fine airframe, no question. Personally I would like a little more "feel" in the controls and a lower stall but otherwise hard to fault. I don't need to tell you they have had their engine problems - I hope the Gen 4 will resolve all of them BUT your list of 1000 hr interventions, does not exactly inspire the confidence I would hope for.

have a great week -Justin Thanks and to you too🙂

 

1 hour ago, BrendAn said:

You are an angry kangaroo lately.

When you insult someone at least own it.

I have no idea what you are referring to - please elaborate.

19 hours ago, BurnieM said:

What does Trump think ?

Think?????????

16 minutes ago, jackc said:

As an aside,  yesterday I looked at an aircraft getting retrofitted with a new Rotax 912IS  and decided

after looking over the  complexity of the job and the differences to the 912 UL it replaced.

I would never consider doing that job.  I would simply have done that job with a Gen 4 Jab motor.  I would suggest ANYONE going to a 912IS is, DONT 🤢

You want to go 912IS?  Just go buy a new aircraft with a factory specced one. 

Speculation:

Compared with the 912ULS

• The main  benefit s of the 912iS would seem be lower fuel consumption, reduced chance of inlet icing and FADEC like engine controls.
• Its claimed 100 hp is the same however I have read reports that it is able to deliver the power such that TO/Climb Out is improved.
• The big downside is much higher upfront cost.
• It has been suggested and sounds logical, that the iS can only be justified (cost effect) by high time flight operations ie training/renting as the savings in fuel will only be returned by such operations.

For my flying, an iS could not possibly be justified, however I would simply go for a trusty 912ULS, as I have now.

10 hours ago, justinjsinclair said:

Hey Skippy, the name is Justin. 
just out of interest have you ever owned an aeroplane ? 
Justin

 

 

Sorry about the spelling fopa.

What has your question "ever owned an aeroplane" got to do with the cost of owning one?

So how come you didn't address any of my observations?

On 17/04/2024 at 8:34 AM, justinjsinclair said:

Hi Glen, I guess we need to compare like with like, I know you are well versed in Jabs 😅 and are Lucid, intelligent and a great thinker.

 

I ..............................................................................................................................................................................................Justin 

 

Hi Justine, Me again - sorry!

I may have missed it in your lyrical support of Jab engines - did you fail to mention/cost that Rotax

• Recommend  100hr oil / filter change intervals. From imperfect, aging memory, this means that Jabs will have 4 oil/filter changes to one Rotax. Cost$$$
• In the same airframe, a Rotax of similar performance to a Jab (ie 80/80 or 100/120) will deliver markedly better fuel economy. Cost$$$ 
• Resale of used Rotax 9's (TBO sales from schools etc) looks pretty healthy. Cost $$$
• Just checked the approximate price of a Rotax 912UL (the equivalent of your Jab 2200) $30K - this is probably base price, so lets say $35K, a tad cheaper than the $40K you estimated.

Rotax 9's are expected to go to TBO (hrs) & well beyond, with little if any major life extending intervention. It can be a bit of a shock when the occasional one fails to deliver on this expectation but really all mechanical devices are subject to failure, it's just a matter of when and how much it may cost, in dollars, loss of amenity & crew health. (none of the later costed by you)

Dont know if Jab 4's have been around long enough to compare but the fact that you have costed sundry life extending intervention, would suggest that they still have some way to go from a reliability (crew health) perspective, loss of amenity (when aircraft in the shop for length repairs).

Speculation; Your costed list below  for the 80 hp Jab ".......from $..." could easily blow out to a replacement engine every 1000 hrs😈

"Current jabiru pricing is 

  2200 Engine Gen 4

** Top End Overhaul            from $5,200
** Full Overhaul                     from $6,300
** Bulk Strip                            from $6,300
**Does not include replacement of substantial items ie. crank, 
cam , conrods, cylinders and heads. Engines must still be running.. 

so in actual fact the Gen4 is cheaper to overhaul every 1000 hours by about $15,000. "

Is it an option to have an instrument maker repair it?

Many many years ago I had a TIF in a rag & tube, high wing, side by side seating, nose pod with windscreen, and a 2/ engine screaming out on the end of a pole in front (Thruster?)

So up I went with the demo pilot, I did notice it was a tad diffrent sensation , to C 172 I was training in at the time.

Anyhow we got up to about circuit height (I think) and the demo pilot asks me if I would like to try an engine out?

Yes says I. Your aircraft said he.

Moments later the engine was reduced to idle - nice!.

Nose down says he. I am says I. Nose down says he ...... ..............

in short he took back control and pointed the nose down VERTICALLY, or so it seemed.

The picture before me was the upwind end of the runway and little else.

Seemed to take a long while (I guess thats funk in action) and then with not further change from nil power, we rounded out, plonked the aircraft down and it rolled may be 3 meters, before he applied power to taxi back to the waiting crowd.

I sooo appreciated my 172 after that.

What I did learn was:

Light/high drag aircraft, when power is reduced/lost, basically stop in the air (low inertia) the lessons from 172 are raise nose to gain height & wash off speed, until best glide reached, then lower the nose, to maintain best glide - I am sure its the same theory for both however the execution is quite diffrent.

Best glide, in a low inertia/high drag aircraft, may appear much steeper, than in a GA aircraft - glide distance/landing options is likely to be severely reduced

Speculation:

If the wheel axle, is ahead of the steering (it appears to be so) the steering may be overly twitchy, pay be prone to oversteer.

A trailing axle (behind the steering) tends to be easier to control and self centering (castering)

You would have to store them very carefully, so as not to encourage pest infestation and subsequent holes.

12 minutes ago, Thruster88 said:

Comparing wikipedia or even manufacturer performance is a waste of time. Adsb shows anyone interested how they cruise in the real world. Cessna 182, 120-130 knots all day every day. 

You are likely correct. Unfortunatly manufactures performance data being suspect, one can only turn to third parties (Wiki) in the hope they may not just be paroting the manufacturer's claims. 

ADSB? - you would need to know the registration of the aircraft, the power setting, engine type, propeller/ load, altitude, OAT, any speed/lift mods - what else? to be able to make determination (data) that could then be used to compare with another aircraft in the same conditions .

Not impossible but unlikly, outside the controlled confines of a competition.

This is why I like competition data - its the only information that is likely to be untainted by marketing hype.

https://www.pipistrel.ad/pipistrel/travel/virus-912

http://worldrecordplane.com/

Thruster my friend, me thinks you miss the point -

Your engine fails, somewhere between end of ground role and achieving circuit height (1000 ft above airfield)- what to do?

Conventional training/wisdom is to land straight ahead (or close to it).

However it clear that , depending on height above terrain/obstacles, when power is lost, pilot competence with the aircraft in question and the characteristics of that aircraft, it may be possible to return to the field (the impossible turn) and land down wind.

There are great risks involved, the aircraft (especially a lightweight RAA one), may rapidly lose momentum/air speed.

This loss of airspeed may result in a stall, when the pilot attempts a turn back (a turn raising the stall speed).

The stall, depending on height above terrain, may not be recoverable.

All of the above, are why a straight ahead landing is promoted - best chance of avoiding a stall/loss of control.

It's not impossible but the pilot must know his/her aircraft very well, especially its low speed handling/ glide/impending stall characteristics.

Anyone who has not practised down wind landings, should do so. The sensation of speed (above the normal) as the aircraft approaches the ground, can be quite disturbing, to anyone not having tried it. The greater the tail wind the greater will be the ground speed.

As an alternative model - Club/Group ownership (does require a critical number to generate the necessary capital).

In my general area (1 hrs drive ) there are two successful group owned strips  - Wedderburn (very successful) & Mittagong.

I fly from The Oaks (under 5 mins) a private (single owner) strip BUT somewhat hampered by limitations, I believe, imposed by the owner. His right but unfortunate.

On 05/04/2024 at 8:47 PM, skippydiesel said:

I  install/fit my own Trigg ADSB & then had it initialised (commissioned) by a qualified/certified technician.

 

Dont have the knowledge to understand your predicament (mix/match) however I had no difficulty having my system passed.

 

Good luck - hope you get the help you need from an electronics person on this Forum 

 

 

6 minutes ago, KRviator said:

If you're the builder of the aircraft (or can maintain it either through RAAus L1 or Instrument 18/22), then you can install the ADS-B equipment and sign off on it for the purposes of the rebate as you're an approved installer. At least, that's how I read it.

And from CAO20.18
 

 

Hi KR - As mentioned earlier - Did my own physical install, applied for unique code BUT had to have certified person do the actual initialising (commissioned).

Initialisation involved electronic gizmos, that also checked out the accuracy of my altitude, air speed, direction measuring equipment.