Zongshen cd 100 /912 clone

[Marty_d]

Man of the people, huh!  Nothing like parking your Roller where everyone else has to trudge in.

[spenaroo]

9 minutes ago, Marty_d said:

Man of the people, huh!  Nothing like parking your Roller where everyone else has to trudge in.

chauffeured in, and it was a Bentley...

it was a special consideration given after he had a stroke, which paralyzed half his body. wheel chair access (just a bigger chair)
apparently he would always send friends/family that arrived in the back seats, to standing areas the stand as it was a poor view from the back.

Edited July 11, 2023 by spenaroo

[RFguy]

NOTE - this engine and the chinese bits were discussed elsewhere in this webiste/ forum.

 

[FlyBoy1960]

3 hours ago, facthunter said:

No I can't and I won't offer an opinion here, except there was a LOT of animosity between the Parties.  Nev

There was never any legal action by the importer to the RAA, never ever.

It was not a Pipistrel Sinus but a TL-Ultralight Sting.

The failure of the crank came because the then owner flew the plane for > 6 months with a spinner he fitted and drilled by hand !

 

Apparently the vibration was so bad he got numb feet after 10 minutes but he kept on flying. He did this for more than 6 months.

All this came to light after the coroners inquest when the full document package was available, which included the owners maintenance records that were not presented in court.

Never let the truth get in the way of a good story !

[facthunter]

I suggested the facts be looked up as All I had was from memory and it's a while ago. I'm fact hunter not fact provider and don't care who gets the credit. Your underlined last line could not be more WRONG. Lets see who nearly sent the RAA broke. I did see the CASA report on the crank and thought it was the result of a propstrike.Just what WAS the big legal problem?  Nev

[BrendAn]

think i will leave that can of worms closed.

[danny_galaga]

On 09/07/2023 at 7:29 PM, skippydiesel said:

Imitator is the sincerest form of flattery

 

If the Chinese  follow the post WW2 Japanese model, they will copy all sorts of technology for a few years, then start improving the copies, then come out with original stuff that is World Class .

 

On this basis, I would expect the next version, to delete all those strange Rotax 9 quirks, that no one seem to know why they do it.

For a short time a couple of years ago, china was number 2 in the world for patents submitted, overtaking Japan. I think they are number 3 again now. Clearly then, they are way beyond just copying stuff. 

 

Having said that, also clearly, this engine is a copy and not licence built. 

 

Edit: I misremembered. They were number one.

 

https://www.visualcapitalist.com/cp/countries-new-patents/

 

Edited July 11, 2023 by danny_galaga

[facthunter]

I'm not trying to have a  go at the maker but really most of that stuff in their line up is NOT Top of the range stuff at all. These days the best ride on Lawn Mower  engines are nearly good enough for a U/L. When something is copied you don't know what parts of it are near limit in the design copied.  Nev

[Area-51]

I don't understand why anyone is even debating this subject. The engines are cheap with unknown reliability. So just buy and install two 🤷🏼‍♂️

[Kyle Communications]

That Zongo engine isnt that cheap anyway...I spoke to them when they popped their head up a few years ago.  At the time I think the Rotax was about 28k but the zongo was about 22k...so it wasnt that advantageous to try on a risk

[IBob]

13 hours ago, FlyBoy1960 said:

There was never any legal action by the importer to the RAA, never ever.

It was not a Pipistrel Sinus but a TL-Ultralight Sting.

The failure of the crank came because the then owner flew the plane for > 6 months with a spinner he fitted and drilled by hand !

 

Apparently the vibration was so bad he got numb feet after 10 minutes but he kept on flying. He did this for more than 6 months.

All this came to light after the coroners inquest when the full document package was available, which included the owners maintenance records that were not presented in court.

Never let the truth get in the way of a good story !

 

Here is the crankshaft analysis: file:///C:/Users/user/Downloads/aair200700054_001.pdf

 

'Abstract
On 6 January 2007, a TL-2000 Sting Sport ultralight aircraft, registered 24-3770, impacted the
ground approximately 30 km north west of Goulburn. The aircraft was fitted with a Rotax 912
ULS Engine. The engine disassembly and inspection was conducted by a Rotax engine specialist
at the request of the NSW police, during which, the crankshaft was found to have fractured.
Recreational Aviation Australia subsequently requested the assistance of the Australian Transport
Safety Bureau in conducting technical analysis of the crankshaft. That analysis found no
indications that would have prematurely initiated failure or have been detrimental to the fatigue
life of the crankshaft.'

 

 

[facthunter]

The LOADS that all pistons stopping twice each revolution impose far exceed anything possible from a poorly balanced spinner.The propshaft bearings take out of balance prop loads NOT the crank end.  There were more comments about the crank failure of a technical nature. Any runout there would cause a lot of vibration as the revs are higher, also.  Nev

[IBob]

Sorry, wrong link, should be:

https://www.atsb.gov.au/sites/default/files/media/24363/aair200700054_001.pdf
 

My reading of that ATSB report is that they examined the crankshaft remains, using various methods.

They verified that the alloy complied with the stated Rotax spec.
They did not find any evidence of any manufacturing fault that may have contributed to the failure.

They made no analysis of the design itself, which presumably was outside their remit.

 

 

[facthunter]

In the whole kerfuffle there was some mention of a prop strike in the planes history. That would be a possible explanation of the shafts condition. They couldn't determine if the interference fit was correct  (as a piece was broken out) nor am I suggesting it wasn't.   There is no way of checking it available...  Nev

[Thruster88]

It is unlikely the crank would have fractured in two places without some external event.

[facthunter]

It was about 1/4 of the circumference of one cylindrical  surface that dropped out so the hardness must have been considerable.. I agree it was overloaded consistent with a prop strike, maybe at some earlier time.   Nev

[BrendAn]

48 minutes ago, facthunter said:

It was about 1/4 of the circumference of one cylindrical  surface that dropped out so the hardness must have been considerable.. I agree it was overloaded consistent with a prop strike, maybe at some earlier time.   Nev

You forget that there is a clutch to prevent overloading the crank.

 

 

[kgwilson]

I don't know the details but a Sling had an Engine failure and landed on Sapphire beach near Coffs a few weeks ago. My understanding is that there was a failure in the valve train somewhere which caused a piston to disintegrate, bending a conrod and crankshaft and distorting the crankcase. There is no coming back from that sort of catastrophic failure. I'd be interested to find out the details, anyone?

Edited July 12, 2023 by kgwilson

[facthunter]

Pressed up  cranks are $#!t . They are already loaded up (strained) before they take any more load due to dynamics  and torsion. There are specific runout test for prop strikes. Let's just assume the possibility of than not being done and the engine continuing in service while out of alignment.  Nev

[Area-51]

6 hours ago, facthunter said:

Pressed up  cranks are $#!t . They are already loaded up (strained) before they take any more load due to dynamics  and torsion. There are specific runout test for prop strikes. Let's just assume the possibility of than not being done and the engine continuing in service while out of alignment.  Nev

Rotax Heavy Maintenance, SEC 72-00-00, Pg23 - Pg25, Propeller Shock Load, Inspection Crankshaft Distortion.

[turboplanner]

On 11/07/2023 at 6:32 PM, facthunter said:

Just what WAS the big legal problem?  Nev

It doesn't need to be muddied up any further. 

[BrendAn]

The intent of this thread was just to make people aware of the you tube videos about the  installation of a 912 copy.  I suggest anyone interested follow the channel to see how it performs .  

[aro]

15 hours ago, facthunter said:

Pressed up  cranks are $#!t . They are already loaded up (strained) before they take any more load due to dynamics  and torsion.

Who has had more crank problems? Rotax or Lycoming?

Lycoming cranks are long and bendy, and bolting a propeller directly to the end was a terrible idea.

[facthunter]

  The larger Lycoming's have dynamic torsion dampers. Why is having a prop bolted on the end of the crank a TERRIBLE idea? There's NOTHING simpler. The prop acts as a flywheel  and if you gear a flywheel you're looking for trouble. Flat motors have the shortest cranks of all (bar radials). Nev

[Area-51]

 

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