Zongshen engine replacement in a Tecnam Bravo

[Kiwi55]

Hi All,

We have just had our second complete failure (engine right off) in our Tecnam Bravo.

Now considering a Zongshen replacement.

Has anyone had experience with this engine?

Dave

[RFguy]

I have had some contact with them a year or two ago. They were good to deal with. 

Price is by negotiation.... I made the point that pricing their 912ULS equiv engine at approx AUD20k ,--- that  people would not pay 20k  for a unknown, non tried and tested product,  when they could pay 28k for a genuine rotax...... That is if people are going to spend 20k, they will spend 28k.

So I think pricing came down to about 15k from memory.

 

I am unsure to whether they are building under license, or buying some critical parts from rotax,  or simply doing their best copy. 

Anyway, what are you doing to the poor Rotax to hurt them ? They DO need cylinder bore airflow, and you need to ensure the oil system doesnt end up with too much vaccuum, and keep them cool but nothing else.....

Edited January 16, 2023 by RFguy

[rodgerc]

Can’t assist with advice on the Zhongshan, but as an owner of a Rotax I’m very curious to learn from your experience and the response you’ve received from Bombadier and Tecnam. 

[facthunter]

In that situation you have a "Factory Installed" engine which should give a measure of extra confidence.  Nev

[Kiwi55]

Hi,

Our experience with the Rotax:

1 (original engine) suffered from the cracked crankcase problem the earlier motors had. No help from Rotax.

2 Freak failure. We had a Rotax carb heat system fitted on the engine (original factory fit). It uses a extra assy fitted to the outside of the muffler which has circular spacer rings separating the outside of the muffler from the inside  of the heater sleeve.

One of the these ring collapsed and a piece found it's way  right through the carb system into the no.1 cylinder. Not good. We are told because of the shock to the engine we need to replace:
Crankcase and crankshaft assy including conrods.

No1 cylinder and piston.

Check gearbox.

Now the Zongshen looks attractive.

 

[rodgerc]

Thanks for the update. I’m comforted by the information, although that’s no consolation to you. 

[facthunter]

Is it really likely to be better or even as good?  A copy is rarely better but there's a lot of room for it to be inferior. Rotax 912 is a critically bult engine not tolerant of  "quality" reduction.   Nev

[Kiwi55]

That is why I am trying to find out users experiences. I don't wont to get involved in the China thing. However this company made 1.1 million motorcycles last years so they must know what they are doing.

Wouldn't be surprised if they make parts for other aircraft engine manufactures. Dave

[facthunter]

Honda don't make an aero engine either nor any other motorcycle manufacturer. though manyhave been adapted. with mixed results.To find an answer to your query will take years with no real guarantees. Talk to the guy who modifies them in SWEDEN. He WELDs the original Rotax cranks which I don't consider a good fix but HE obviously considers it necessary.. HIS motors no longer have ROTAX anywhere on them..  Nev

[RFguy]

Try the Zongshen. for you, from your point of view, cant be worse...

 

Edited January 17, 2023 by RFguy

[facthunter]

Can you guarantee that logically?  Nev

[RFguy]

But I agree with you Nev, I would consider a Rotax a much more difficult, sensitive and critical  engine to copy well. compared to say, a Jabiru. 

[facthunter]

Yes  that's my analysis pretty much. Some Lyco Clones haven't been too good when the orig 360 is as reliable as any. Nev

[Old Koreelah]

As Kiwi says, Zongshen should have built up considerable expertise by now. For years they sponsored an Endurance racer I know. Admittedly their race bikes were Suzuki-based, but surely contributed a lot to their street bike designs. 

 

[facthunter]

I've got a lovely Harbour bridge to sell cheap with only a few burn marks from fireworks.. Hell who even knows someone with one?   Like testing a rope bridge over  a swollen river with an overloaded truck. After you sir. Nev.  

[Bruce Tuncks]

My son has a chinese ute which has gone for years and still is ok. It is a Great Wall, and he reckons he could give it away for nothing and still be way ahead of those who paid double for a "known" brand.

Here on the farm, I use a chinese tractor and it is much better than the US-brand-name ( Massey Ferguson ) one which preceded it. The US one turned out to have been made in Mexico, and among other problems, it was controlled by a computer.

So while I agree to be wary, I reckon that you could be wrong to assume that the chinese motor will be inferior. It may even be better! The only problem so far with the chinese tractor  is that the hydraulic fittings  are not standard, so I can't buy spares locally. I had to buy them online and wait a week for delivery from WA.

[facthunter]

Test one if you wish . It's an AEROPLANE motor and at times your life will depend on it. Most aeroplane motors aren't that good even  though they cost heaps to produce. The "famed " Merlin never exceeded 650 hour s  for a time to rebuild. Not should it. It was designed for a fighter plane. Only ever certified for civilian use in a few countries due to the single skew gear magneto drive to both magnetos. They also suffered from scuffing of the non roller cam followers on start-up at times.    Nev

[onetrack]

When the Zongshan throws a leg out of bed at 5000 feet over tiger country, will the few thousand dollars saving, really seem worth it?

 

It takes at least a decade for a manufacturer to establish a solid reputation for reliability, excellent QC, good parts and service backup, and good technical support.

 

Remember at all times, the Zongshan is simply a cheap copy, possibly using stolen information, likely to be ignoring patents and registered designs, using manufacturing processes of unproveable abilities, and possibly corrupt components and materials suppliers - and you want 100% guaranteed reliability, at 2/3rds the purchase price of the genuine article?

 

It's not going to happen. If you purchase one, simply expect it it to fail - and more than likely, at the worst possible moment. The book, "Poorly Made in China" is a good read.

[facthunter]

Another Gamble with the China replacement what effect will it have on the resale value of the Plane and is the different motor certified?  Nev

[facthunter]

Reverse Engineering has been proven to produce a lot of pitfalls. Eg an existing design might already be on stress limits and require exceptional fits and materials  and heat treatment precision to be marketable and reliable. They have no experience of it in the field as the original manufacturer does. IF there's no arrangement and cooperation with Rotax then I would be very wary of  being involved with it and it's UNLIKELY that they do.. I also don't have the view the 912 has all the answers for the U/L pilot as many have thought and promoted. It should be fuel injected for starters. It's expensive enough to get them already fitted.  Nev

Edited January 17, 2023 by facthunter

[RFguy]

In general, but not always, ---in China quality  at least on high volume parts, is reduced until the customer complains. I'm not quite sure how that works with airplane engines.

Most of it is junk

but they do make some good stuff. I buy my miniature coax cables from a single supplier on the HongKong border who has not made a bad nor failed cable in 10 years...

The high end printed electronic circuit board business is interesting. it's labour intensive , and hard. lots and lots of precision. 12 stacked layers with blind internal  interconnects over 300x300mm all stacked up in X and Y within 0.02mm.... and the best complex circuit boards ( IE before parts are soldered to it) come from China, no doubt about it worldwide. Working on low margins with extremely complex  requirements and every circuit board is 100% tested for its literally thousands of connections internally .....I guess that hones their skills when they will go out of business if its not right and every single article is 100% tested for quality. 

But plenty of other stuff - like some of the cheap tools they sell, wel they really are first grade junk.  and look at half the stuff in bunnings. junk.

 

I did talk to the ZOngshen gentleman about getting a single engine at low cost to demonstrate to local market (if it was any good). that was 2021 but in the end I bought a used 1900 hour 912ULS. 

 

 

 

 

[RFguy]

By the way Kiwi, the 914 'lookalike' was 30k aussie. 912uls lookalike was 16k aussie. 

 

I wonder if they followed suite of rotax when rotax recently in a service bull uprated all the exhaust valves in the 914  ?

[facthunter]

I  spent a fair bit of time on their site. Not really impressed with their targeted market. I doubt there's any way it would be certified. Of course the Chinese can make good stuff but making money is what they are best at (and gambling).. Nev

[Bruce Tuncks]

We come down to the test which will tell if a motor is about to fail. I sure would like to know of these tests.

Leakdown?.....Nahh

Compliance with AD's....  nahhh

So, what is the best I can do?

[Kyle Communications]

I think you will find a new 912ULS is around 36 to 37k here now