Jabiru vs Rotax

[AndyCAP]

I am new to this sport and want to get into 3axis microlight flying. I am 6'7,5" tall and as a result I dont fit into may planes! I've checked out the Cheetah XLS and so far it seems to be the best option (space wise). I still intend to check out the Bushbaby, A22 Foxbat & Thunderbird

I have however had quite a bit of conflicting info about the reliability engines - particularly the rivalry between Rotax & Jabiru. I know I'm probably opening a can of worms, but where can I get stats on engine reliability of Rotax 582 and Jabiru 2200 (80 or new 85hp)? Are these stats accurite - or are most engine failures which are followed by successful emergency landings not reoprted?

My current thinking is to build a Cheetah from a kit and fit it with either a Rotax 582 or Jabiru 2200 (I would love a 912 or 912s, but the cost precludes it at this stage)

Cheers

AndyCAP

[Junkie]

Why not go for the 3cyl 100hp Hirth Fuel injected motor,
its lighter and way more powerfull than a 582.

By all accounts looks like it will be more reliable too

[AndyCAP]

I've never even considered this motor - they are not used frequently in SA are they? will check on the Net for more info (local supplier etc)

Thanks for the feedback though!

[AndyCAP]

Thanks for your view Demon. I would prefer to have a 3axis machine - would love to progress to a homebuilt (e.g. RV7) some day. For now it looks as if the hole in the roof idea is not too bad - just need some goggles though! Vladimir recons a modified seat mounting bracket and some bulged roof panels may be a bit more elegant though!

[Martin]

ROTAX is a solution for those who really want to fly. The others who prefer to spend most of their free time in hangar repairing and maintaining their engines should consider Hirth, Jabiru, Verner and other similar "products".

[Aviation Engines]

I do not believe in "Slagging off" other products, but this one needs some facts stated which is clearly lacking here.

Yes, the Rotax is a more expensive engine and cannot be compared to other engines.

The 912 engines are available in certified versions to JAA and FAA requirements. The non-certified versions are exactly the same, just without the Release Certificate.

To get an engine FAA approved, in short, the following test procedure has to be followed:
The first production engine is run in a test cell for 50 hours at full power with all operating limits (oil temp, pressure, cyl hd temp, etc.) in the normal range (in the green).
The engine is then checked and run for a second 50 hour period, also at full power but with the operating limits at maximum (in the red).
The 3rd 50 hour period is run at it's maximum continuous power (eg. 75% power) and with the operating limits at maximum (RED).

The total 150 hours is the minimum required by FAA.

The engine is then completely stripped down, inspected and all wearing components measured and MUST be within the new part tolerances.
The FAA requirements are of course far more detailed.

Rotax has passed and exceeded these requirements and I am interested to know if any of the other engine makes being compared have been put through these tests, does anyone know?

Rotax is an Aircraft Engine and has been specifically designed for that purpose. In a book entitled "Tips on Engine Care" published by Teledyne Continental Motors Inc it is quoted:
"In reality, the aircraft engine has very little in common with the stock automobile engine in terms of operating procedures. the aircraft engine is the athlete of it's species and it was designed for high power output."

Your standard car engine is seldom operated at more than 60% of it's maximum power, in fact it is running at 30-40% of it's max power almost all of it's life. An aircraft engine is run mostly at 75% to maximum all of it's life. The car engine does not have a prop spinning on it, to compare, take a 5 ltr bucket of water and swing it around in your arm and see what it does to your shoulder socket.....................

Another interesting fact is that Titan Aircraft in the US have stopped using Hirth engines and do not recommend the use of them due to the high number of fatalities caused by engine-outs. Other aircraft manufacturers in the US may follow soon.

Each Rotax 912/914 engine is test run on a dyno and all operating limits are checked and recorded including the power output at various rpm's. The test run period is between 30 and 45 minutes. Many other inspections are carried out before the engine is ready for delivery. The detailed test report is available on request for each engine. Send an e-mail to tech@aviation-engines.co.za with "Test Run Protocol - (serial no.)" in the subject field and I will forward your the report in 3-4 days.

All Rotax engines, 2 and 4-stroke are manufactured in accordance with ASTM standards.

The 582, although 2-stroke has proven itself over many years and in 100's of applications as the choice for affordable flying all over the World. It still offers the best power-weight(-cost) ratios. 90% of Rotax engine failures have been a direct result of shortcomings in the installations, especially the fuel systems, pay special attention to this aspect of the installation. The same applies to the 912 engines.

If your want to enjoy your flying and if you want to do it safely, use a Rotax, do the installation with safety in mind, READ THE MANUALS (seldom done), maintain it properly and please if your have any questions, ask me first before going to your nearest Rocket Scientest!

Regards
Niren
Aviation Engines & Acc

[RudiGreyling]

<SNIP>
Yes, the Rotax is a more expensive engine and cannot be compared to other engines.
<SNIP>

Hi Niren,

That is exactly the reason why it DOES need comparing to other engines. You simply can't say you can't compare?

You say you pay more because you get more, and people need to be able to justify that purchase.

I can understand the differences and riqerous testing the 912/914 certified version goes through, but what distinguisses the 503 and 582 from other engines? (other than saying it has a manual and has proven itself)

Please back that up with some facts, otherwise it just looks like a biased opinion from the supplier, and it does looks like "slagging" from where I am reading.

FACT: Rotax is more expensive...WHY: is not clear.

It seems that people follow the crowd for the sake of inertia, and suppliers take advantage of that inertia, but that is just my opinion. The same is true for Microsoft software and Lycoming engines. I am currently flying a Rotax, I do not know what I will do on my next plane, but I do know competition is good for the consumer. I'd like to see more competition, since I am a general consumer.

Kind Regards
Rudi

[Aviation Engines]

The comparison I refer to is one of certification and I merely wanted to state the process required by FAA.

What kind of facts do you want about the 2-Stroke engines? The wide use of these engines speaks for itself. For more information about Rotax, go to www.rotax.com

It was not my intention to Slag off any products and if that is what was conveyed, my apologies.

The costs in getting certification is quite substantial, I do not know the exact amounts. The quality systems involved in the production of aircraft engines are far more intensive than for other applications. R & D costs are recovered over a much smaller number of engines than it would for eg. automotive engines.

Why is a Mercedes-Benz or BMW more expensive than KIA or Toyota?

The suppliers who take advantage of the inertia you refer to have good foresight and are therfore successful businesses. People who follow those trends obviously feel that the product satisfies their needs.

[DieselFan]

Why is a Mercedes-Benz or BMW more expensive than KIA or Toyota?

I don't think it's fair to use the German VS Jap car comparision here as with a BMW one gets more than just the engine and not too mention the ever important STATUS, which I believe ROTAX has and rides on.


Firstly these general across the specific brand.

Lets see
Toyota = lower performance figures, recognised reliability using older (proven) technology, shorter service intervals.
BMW more modern = not widely reliable, higher performance, longer service intervals
KIA = Average (neither low or high) but reliable and uses a mix of old and new tech. Average service intervals. Did you know the longest running generator in SA is Korean and the loads experienced are quite varied?
Merc = Low performance figures, reliable and built to last the next 10 owners..., long service intervals.

Due to more local competition the gaps between service intervals have shrunk.

But now should I buy a kia motor which comes out tops in Price / Perfomance / Reliability?

In terms of Technology, VW's current Chico models have OLD Carb engines , yet are very cheap and they have being producing these engines for a long time. It is EXTREMELY rare to find a car with Carbs. 98% of new cars have new tech in terms of ECU's etc. Surely ROTAX has recovered it's costs of the 503 and 582?

"The wide use of these engines speaks for itself" - This reminds me of the Toyota debate , ignorance is bliss ie it is no longer accurate to use that statement ESP if there's no one to compare it to yet...ROTAX strikes me as a good reliable STATUS engine, that needs competition from the Japs, Australians etc. to improve in technology and price.

Personally I've only heard good of Rotax and bad of Jabiru, but I wonder if it's not the same as the argument about ML's being unsafe?

Motorbike engines are most like aircraft motors in terms of operating loads.

I also know of many people who have fitted VW V5 motors to their bliks and have logged many hours with them. What did merc and BMW start off with? My point here is it can't be THAT hard to develop an aircraft engine over any other type. Mostly there should be compression levels etc to adjust to more extreme temps.

Did you know that Hondas and Mercs are run in for over 90 Hours at FULL throttle - This I learnt from a publisher of a motor magazine.

----
Before I get flamed for generalising above:
Please note I have been fortunate enough to own one or two of each of the above marques and I'm not saying one is worse/better than the other but they are what each marque is known for and you dont JUST BUY the engine...

PS
I will most likely also get a Rotax, but would LOVE to try something else just for the sake of not being mainstream

[RudiGreyling]

Hi Niren,

Thanks for your reply. I do not want to get into an argument and I do not want to ‘slag’ your product. I genuinely & seriously would like to understand why a Rotax is sold at a premium, and what I get for that.

My response to your writing in blue and my question is in red.

<SNIP>
What kind of facts do you want about the 2-Stroke engines?
I would like facts to back up your statement that they can't compare to other engines.

<SNIP>
For more information about Rotax, go to www.rotax.com
I did visit rotax.com but the site does not give any useful info on aviation engines, your web site has much more data on the aviation engines.

It was not my intention to Slag off any products and if that is what was conveyed, my apologies.
As a single consumer I accept your apology

The costs in getting certification is quite substantial, I do not know the exact amounts.
Agreed on certification, but I still query the non certified engines.

The quality systems involved in the production of aircraft engines are far more intensive than for other applications. R & D costs are recovered over a much smaller number of engines than it would for eg. automotive engines.
I Agree, that is why aviation engines are more expensive in general. Why Rotax is even more expensive than other 'equivalent' aviation engines is not clear. Rotax have almost captured the market, so they sell much more engines than other manufactures, so they should recover their costs sooner, yet the uncertified engines are priced at a premium. Why is that? What do I get for it as a consumer? More reliability, better service, backup, spares? Just say it and back it up with facts.

<SNIP>
The suppliers who take advantage of the inertia you refer to have good foresight and are therfore successful businesses. People who follow those trends obviously feel that the product satisfies their needs.
I do not want to follow inertia for the sake of it, I want a factual understanding what is behind it. If there are no facts behind it, then it is just inertia.

Kind Regards
Rudi

[AndyCAP]

Its good to see all the opinions and so far the 'flow' seems to be very much in favour of Rotax.

But where are the Jabby enthusiasts?? You dont have to slate the opposition, just tell us why you like Jabiru motors and how you are experiencing them in service?

I have spoken to a number of people in the flying community recently and have come up with the following disadvantages of Jabbies:

1) They swing a smaller prop since they dont have reduction drives
2) Can only use Avgas up here at the Highveld
3) There is a perception that they are not reliable.

The last statement has been contradicted by the guys at Aerosud based at Swartkops, who train PPL's & MPL's on Jabiru aircraft. The same feedback (on reliability) was given to me by a bunch of Bantam owners during a Bantam breakfast run I attended in Nelspruit. In both cases you could argue that the parties involved are not likely to advertise negative facts about their engines.

Judging by the light aircraft survey that was recently published (Aug '05??) in African Pilot, Jabiru aircraft and Jabiru powered aircraft (Bantam) are very popular in SA. The balance are powered by Rotax and admittedly the survey did not include Trikes, of which I would guess about 90% are rotax powered.

So far I think Rotax is perhaps a safer option (for me) due to the backup service available in SA. But it is more expensive - at least here at the reef one can still use Unleaded Petrol instead of Avgas which will help a little cost wise.

I do however think that people underestimate Jabbie motors and that given the ol' test of time, they may just become a lot more popular (providing they remain competitively priced)

[/b]

[FAWGie]

I've never even considered this motor - they are not used frequently in SA are they? will check on the Net for more info (local supplier etc)

Thanks for the feedback though!

The SA agent's name is Warren and his contact number is: 083 997 9814...

[FAWGie]

But where are the Jabby enthusiasts?? You dont have to slate the opposition, just tell us why you like Jabiru motors and how you are experiencing them in service?

I am fortunate to own a few aircraft including one with a Rotax 912 motor and one with a Jabiru 3300 motor, so will pass a few unbiased ownership comments...

* The Rotax motor was introduced into a world market long before other brands got any market dominance. I do agree with the sentiment that Bombardier could make their un-certified product far cheaper considering the sheer production volume that they do and supply into a world market....Rotax have refined their product relaibility over time, kept the engines simple and thus built up a reputation....

* The Jabiru engineis a new comer if you want to compare it to the likes of Rotax...Yes, there were engineering teething problems in early generations of the 2200 engine, but these have been long resolved....World wide, Jabiru engines are giving Rotax a run for their money and if you gloss over a kitplane mag listing all kits avaiable, you will be surprised to see how often the Jabi motor is recommended....

* The direct drive is far better than thru a gearbox, even if it means a small prop being swung, but in tractor config, the ground clearance should be preferred....

* I have found both engines extremely reliable, BUT, both engines require proper maintenance to be carried out......cut corners on any engine and it will bite.....

* The Jabiru motor starts faster than the Rotax and runs smoother...Regarding the perception on Jabiru motors....Flying was considered unreiable not too many years ago....These engines have come a long way!!!

Considering that there are so many Rotax's as well as Jabiru motors flying in SA (over 250), I am comfortable with both types......

Then there is the debate of 2 stroke versus 4 stroke.....If affordable, go 4 stroke !!! Even though in many cases, a light plane performs better with a Rotax 582 from a power to weight ratio.....

[AndyCAP]

Thanks for the info FAWG

I have searched the net a bit and have come to the conclusion that you either LOVE Hirth or you HATE it. Unfotionately the most seem to fall in the latter category. They seem to have a particularly bad reputation in the States. As is frequently found most of the sentiments found seem to be based more on opinion than on fact.

As far as I can gather, Hirth are not even close to being a big player in the SA market and as such it does not make (in my opinion) a lot of economic sense in terms of resale value to go with a relatively unknown product.

For all I know it could be a very good product, but I think it will take a very big marketing effort (and testing thats visible to the microlighting community) to convince more pilots to consider it as a powerplant.

I'd rather let others pay schoolfees - particularly when your safety could be at stake!

Suppose it would have been different story if we were on an airboat forum though - then at least if the thing quits you can paddle home!

[RV4ker (RIP)]

Interestin reading.

Question?

Why no Jabi motors on trikes?