Zenith Aircraft Builders and Flyers
Online Community of Zenith Builders and Flyers
Emergency Landing: Viking Engine
I had an engine failure in flight a few days ago. We were about 3 minutes out of the field and about 1200 feet AGL when there was a loud pop and a moderate level of vibration started. A liquid appeared on the canopy but it did not look like oil. A quick 180 was done and power reduced to the lowest level to maintain altitude until we were with in glide distance of the airport (perhaps 45-60 seconds). An emergency was declared and we landed downwind in the opposite direction.
The Honda engine behaved flawlessly even with what turned out to be an almost total loss of coolant. We were able to taxy back to the hanger leaving a trail of coolant behind.
The failure was that the "spider/plate" on the back of the gearbox lost one of its three sides. It exited the aircraft making a hole in the cowling and badly damaging the coolant pipe and radiator.
On looking on line, it seems that this failure mode seems to have been happening more frequently. Of course since this is in an experimental, there is no central place where all these failures are reported.
I am now quite sure that these failures have all been caused by miss alignment between the gearbox shaft and the engine crank shaft. The gear box is mounted on long standoffs which are non precision and do not offer any way to insure the alignment of the shafts. Jan provides an alignment disk when assembling the gearbox but that does not insure anything as if there is any misalignment, the disk will be slowly destroyed. Additionally the mounting standoffs are positioned asymmetrically so that the engine and prop torque will introduce additional alignment errors. Even a few thousands of misalignment results in a flexing force on both the spider and flywheel. This is happening 5000 times per minute. Only spring steel can withstand this but that alloy would not be suitable for these applications. The result is metal fatigue and ultimately failure.
I have noted to others that we have known for almost 100 years now to mount a transmission on an engine. It is done with various variations of a bell housing and alignment pins or the equivalent. Jan thinks he knows better and provided a system that has no alignment mechanism.
If this was a certified/production aircraft, I am sure that there would have been an AD grounding the fleet until there was a proper fix. Personally, I would ground all viking installations. For those who continue, I would frequently replace the spider, rubber isolator and flywheel, probably at intervals of no mare than 100 hours. Even that may not be enough as I believe there was one failure in under 100 hours.
I have included pictures of this event.
I am retiring the viking package and may put a UL or Rotex engine in. I see no way to modify it to make it reliable short of designing a whole new gearbox. Even then since jan chopped off one of the Honda alignment pin holes, making anything that would align like a Honda transmission is probably not possible.
- Attachments:
-
-
PXL_20221029_171801081.jpg, 1.2 MB -
PXL_20221029_170638385.jpg, 1.3 MB
-
PXL_20221029_172731272.jpg, 1.3 MB
-
Replies to This Discussion
-
Permalink Reply by Glenn Davis on
-
Hi Mark
This is the first I've heard of this type of failure. Can you source the other failures?
Thanks
Glenn
-
Permalink Reply by R Michael Moore on
-
100% Agree with Glen Davis. Full Disclosure is essential.
To say "Looking Online" ... "Happening more frequently" is not proper or sufficient with such a serious matter. That is Internet speak.
It is more than just a courtesy to provide the details of similar failures referred to. It is an obligation.
Please present the actual links so we can see the facts.
Thanks
-
Permalink Reply by Jan Eggenfellner on
-
I had an engine failure in flight a few days ago. We were about 3 minutes out of the field and about 1200 feet AGL when there was a loud pop and a moderate level of vibration started. A liquid appeared on the canopy but it did not look like oil. A quick 180 was done and power reduced to the lowest level to maintain altitude until we were with in glide distance of the airport (perhaps 45-60 seconds). An emergency was declared and we landed downwind in the opposite direction.
BE SURE TO NOT CALL THIS A VIKING ENGINE. YOUR OWN ECU DESIGN (THE PART THAT RUNS EVERYTHING FROM START TO STOP, MAKES THIS YOUR ENGINE DESIGN)
The Honda engine behaved flawlessly even with what turned out to be an almost total loss of coolant. We were able to taxy back to the hanger leaving a trail of coolant behind.
The failure was that the "spider/plate" on the back of the gearbox lost one of its three sides. It exited the aircraft making a hole in the cowling and badly damaging the coolant pipe and radiator.YOU ARE THE ONLY ONE WE KNOW OF THAT HAS TAKEN THE GEARBOX APART AND MADE YOUR OWN INTERPRETAITONS OF HOW TO PUT IT BACK TOGETHER, ETC. (SO, IT IS YOUR GEARBOX DESIGN)
YOU WOULD HAVE AVOIDED LOSING ANY COOLANT IF YOU HAD SIMPLY FOLLOWED THE SERVICE BULLETINS OF THE COMPANY THAT INITIALLY MADE THE ENGINE YOU MODIFIED. THERE IS A WRITEUP DOWN ON THIS PAGE UNDER THE 110 ENGINES. Service Bulletins — Viking & Valkyrie Power (squarespace.com)
THERE IS A SERVICE BULLETIN ON THE COOLANT TUBE LOCATION AND ON THE DRIVE COUPLING. WHERE WOULD YOU LOOK FOR A SERVICE BULLETIN, OTHER THAN ON THE ENGINE MANUFACTURERS WEBSITE?
On looking on line, it seems that this failure mode seems to have been happening more frequently. Of course since this is in an experimental, there is no central place where all these failures are reported.THERE HAS NEVER BEEN SUCH A FAILURE REPORTED AFTER A SERVICE BULLETIN WAS EXECUTED 8 YEARS BASCK AND ALL ENGINES WERE OFFERED FREE REPLACEMENT PARTs THAT WAS DESIGNED FOR THE MORE POWERFUL 130 HP ENGINE. YOU NEVER TOOK ADVANTAGE OF THIS FREE OFFER.
I am now quite sure that these failures have all been caused by miss alignment between the gearbox shaft and the engine crank shaft. The gear box is mounted on long standoffs which are non precision and do not offer any way to insure the alignment of the shafts. Jan provides an alignment disk when assembling the gearbox but that does not insure anything as if there is any misalignment, the disk will be slowly destroyed. Additionally the mounting standoffs are positioned asymmetrically so that the engine and prop torque will introduce additional alignment errors. Even a few thousands of misalignment results in a flexing force on both the spider and flywheel. This is happening 5000 times per minute. Only spring steel can withstand this but that alloy would not be suitable for these applications. The result is metal fatigue and ultimately failure.
I have noted to others that we have known for almost 100 years now to mount a transmission on an engine. It is done with various variations of a bell housing and alignment pins or the equivalent.Jan thinks he knows better and provided a system that has no alignment mechanism.
AND CLEARLY, YOU ARE ADMITTING HERE THAT YOU HAVE NO IDEA OF HOW THE ALIGMENT WORKS.
AGAIN, DONT COMPARE YOUR ENGINE TO A VIKING ENGINE. YOU ARE OPERATING A HOMEBREWED ECU. YOUR GEARBOX HAS BEEN MODIFIED / OPENED BY YOURSELF. YOU CLEARLY DO NOT UNDERSTAND THAT THE WAY THE GEARBOX IS ALIGNED, USING A PRECISE AND DISPOSABLE ASSEMBLY BUSHING, IS A VERY ACCURATE WAY TO ALIGN THE CENTER OF THE ENGINE WITH THE CENTER OF THE INPUT OF THE GEARBOX AND HAS NOTHING TO DO WITH THE ATTACHMENT HARDWARE. AS FAR AS TORQUE UPSETTING THE WORKS, THE 130, 150 AND 195 ENGINES PRODUCE A LOT MORE POWER, WITHOUT ANY ISSUES. PILOTS SEND THEIR GEARBOX TO VIKING IF ANY REPAIR ARE NEEDED, USE A NEW CENTERING BUSHING EACH TIME AND OPERATE THEIR ENGINE WITH A VIKING ECU THAT WAS TUNED BY VIKING.
If this was a certified/production aircraft, I am sure that there would have been an AD grounding the fleet until there was a proper fix. Personally, I would ground all viking installations. For those who continue, I would frequently replace the spider, rubber isolator and flywheel, probably at intervals of no mare than 100 hours. Even that may not be enough as I believe there was one failure in under 100 hours.
I THINK IF YOU HAD UPDATED THE PARTS AS NEEDED, AND DONE THE INSTALLATION CORRECTLY, YOU WOULD NOT HAVE THIS ISSUE. ALSO, AS OUR ATTACHED EMAILS WILL SHOW, YOU HAVE ALWAYS HAD YOUR OWN IDEAS ABOUT HOW TO DO STUFF.
EMAILS:
Mark:
As stated many times prior, we suggested multiple times to send the gearbox here for us to look at along with the hub.We have NEVER had this issue, and we suggested you send it in.I don’t understand why you do not want to send it here? We have the proper tools necessary and everything here to compare and fix any issue you may be having.That has and still is our suggestion. We can not verify anything from a distance and you have opted to do this on your own, so we are unaware of what has been done or what needs to be done.AlissaSent from my iPhone-------------------------------------------------------------------------------------------Thank you, but I did state in the past why it is not coming off other than to replace the engine.Mark Hubelbank----------------------------------------------------------------------------------------------On 4/3/2018 3:24 PM, Alissa Daniel wrote:Just a follow up to my previous email. Just wanting to make sure that you are aware that the gearbox has to be completely disassembled so the spider can be pressed. If not it will cause internal damage.Thank you,Alissa Daniel------------------------------------------------------------------------------------How do I place the order?Mark Hubelbank--------------------------------------------------------------------------------------YOU ALSO MENTIONED BY EMAIL THAT YOU DID NOT NEED A NEW TORSION DAMPER, BECAUSE YOU HAD YOUR "OWN"?YOU WERE ALSO RELUCTANT TO SEND THE GEARBOX HERE WHEN YOU HAD A PROP SEAL LEAK, BECAUSE YOU SOMEHOW THINK A SPECIAL JIG IS NEEDED TO INSTALL THE GEARBOX AFTER REMOVAL. THIS REMOVES ANY CREDIBILITY TO YOUR SUPOSED MECHANICAL KNOWLEDGE. YOU ALSO REMOVED THE PROPELLER HUB YOURSELF AND SAID THE REPLACEMENT WOULD NOT FIT WHEN THE THEY ARE ALL IDENTICAL. YOU SOMEHOW MODIFIED IT YOURSELF AND USED IT. YOU SENT A PICTURE OF IT SCRAPING METAL, SHOWING IT WAS NOT PRESSED ON STRAIGHT.AND NOW THE CONCLUSION: THE REASON YOUR GEARBOX IS GOING THROUGH ONE DAMPER AFTER ANOTHER IS BEACUSE YOU ONLY REPLACED HALF OF THE PARTS YOU RECEIVED FOR THE UPDATE. TAKE A LOOK AT YOUR SECOND PICTURE YOU ATTACHED ABOVE. THE DRIVE COUPLING THAT IS ON THE GEARBOX IS NOT THE NEW ONE. YOUR INVOICE SHOW THAT YOU WERE SENT THIS PART. YOU ELECTED NOT TO SEND THE GEAROX HERE, THEN YOU FOUND OUT THAT ALISSA WAS CORRECT IN THAT THE NEW COUPLING HAD TO BE PRESSED ON AND SHE BEGGED YOU TO SEND THE UNIT HERE. YOU DID NOT WANT TO DO THIS AND USED THE EARLIER PUSH FIT PART. THIS PART ALSO HAD THROUGH BOLTS TO HOLD THE RUBBER TORSION DAMPER, RATHER THAN PINS, NOT ALLOWING IT TO BE FREE FLOATING ON THE PINS. THIS ADDED STRESS TO THE COUPLING WHEN THE BOLTS WERE TIGHTENED AND DISTORTING THE RUBBER. HEAT WOULD BUILD UP DURING OPERATION, ETC. THE UPDATED DESIGN IS RIGHT NEXT TO YOUR AIRPLANE IN YOUR SHOP AND IS STRONG ENOUGH FOR 195HP AND 500 HR.FOR THOSE THAT WANT TO STUDY PICTURE 2, THE BOLT HEAD CAN BE SEEN AT THE LOWER PART OF THE COUPLING, IN THE MACHINED CUTOUT OF THE GEARBOX. ON THE GEARBOX SIDE.I'm happy you landed the plane safe, but when/if you are ready to send the gearbox in we can go through all of this for you.
The way I recall you also had a pretty large amount of hours on this setup as well.
We just simply believe and know the "issue" here is misplaced. To state that all Viking engines should be grounded based on your interpretation and flying outdated parts, as well as stating "many" have had this issue is so far from the truth - there are over 1400 engines in total at the end of this year in the field, this issue has only happened to you after service bulletin.
The service bulletins above came into effect for a reason, about 8 years ago, by one gentleman having an issue - it was adhered to by most. Being "experimental" also removes a lot of accountabilities from the builder/flyer.
-
-
Well
Marks allegation ended like I thought it might.....DEbunked.
I've southern engineered a couple of things on my plane I came to regret and it was nobody's fault but mine.
-
Permalink Reply by Jonathan Fay on
-
Which model of Viking was this? How many hours?
-
-
When I first got my engine 4 years ago it was secondhand. I had the pin drives that were covered by the bulletin and I was a bit upset to have to immediately replace parts on a zero-hour engine, but I did because Viking was insistent that it was critical and I should not fly with the old parts. I see the same part on the failed gearbox pictured above. While the engine pictured is a 110 and I have a 130, it was the failure in a 110 that was the reason for the service bulletin in the first place. What I do know after 250 hours and over 3 years flying my Cruzer with the 130 is that Viking is vigilant about improving their product and learning from every issue encountered by customers. I have seen firsthand the brutal openness they have dealt with operational issues with their products, and I have seen them respond to immediately improve when they find anything that can be improved, even if it has not caused any issues.
I also see how disingenuous the "if this was a certified/production aircraft, I am sure that there would have been an AD grounding the fleet until there was a proper fix." comment was. There was a service bulletin. The owner ignored it and clearly the broken part was under the service bulletin for years and he still flew with it. Ignoring anything Jan posted, the pictures that were posted in the thread show the old parts. This should never have been signed off for a single Condition inspection with an unimplemented service bulletin.
Trying to blame Viking for your non-compliance is a serious denial of your own responsibility. If you ignore the manufactures recommendation and go your own way, then you own the responsibility for the outcome.
-
Permalink Reply by John Austin on
-
Jonathan,
I agree with your comments and certainly think it is critical that the service bulletin be followed and implemented, especially since it pertained to such a critical component! However, just to clarify for any novice builders/flyers, service bulletins are not mandatory unless an AD is issued than incorporates the service bulletin. Additionally, AD's are not applicable to experimental aircraft unless specified in the AD. So, a condition inspection can be signed-off despite an outstanding service bulletin (and no AD), but not signed-off if there is an AD specifically addressing the experimental aircraft, engine, propeller, etc.
Again, I concur with your comment that the specific service bulletin mentioned should have been addressed!
John
N750A
-
Permalink Reply by Jerry Griego on
-
Thanks for your post. We as experimental home builders are always trying to save money because this hobby of ours is expensive. It is far cheaper to have qualified professionals do some of the work. It sounds like Viking Aircraft tried to help you out. Of course it would have cost you a little money but it would have been worth it. I have a Zenith 701 and a 650. I flew a Jabiru and it froze up on the ground twice., I then bought a Rotax 912ULS and it blew up in the air. Bought another Rotax and 26 hours later it is still working. If you think Rotax and UL are going to solve your problems, good luck. It is almost impossible to have someone ask you to send in the part so they can solve the problem. Jan tried, you won't get that from those other guys. Sometimes you have to spend a $1000 to save $30,000.
-
-
Jerry,
I think your experience points out that no brand of engine is immune to problems! Some look to certified engines from major manufacturers such as Lycoming and Continental as being the "gold standard." However, in 1999 I bought a brand spanking new Cessna Stationair (C206H) that was supposed to have a new engine, a Lycoming IO-580. However, during testing it had problems and Lycoming and Cessna used the IO-540 instead - a "tried and true" engine with hundreds of thousands (?millions?) of fleet hours. Things didn't work out so well ... those engines started breaking crankshafts and eventually an AD was issued to get those cranks out of service. Lycoming supplied a basket of parts - new crank, etc - probably worth $20K for a bargain price of $2K but did NOT reimburse for labor. I was out-of-pocket about $11K+ as I recall. So, even a "gold standard," "tried and true" engine line can bite you!
(BTW, this fiasco all happened because Lycoming specified a change in the steel alloy mixture in the crank. The forging company advised against this change, but Lycoming was insistent. Later, when the crank problem became apparent, Lycoming sued the forging company and lost! Unfortunately, a class-action against Lycoming for the engine owners went nowhere - it was simply drawn-out and lawyered to death until the suit went away.)
OK, rant over. I feel better now, but not $11,000 better!
To summarize, the only airplane I'm aware of with absolutely never, ever any engine problems is a glider! :)
John
N750A
-
Permalink Reply by Dave Blackburn on
-
Mark, I'm changing out my Viking 130 (let me down at 77.5 hours - coolant circulation failure). Lost the engine but saved the airframe. Currently installing new firewall forward package of UL 350. It's a lot of work, but I think it's worth it. No engine is bulletproof but running an auto conversion engine at rpm's it was not designed for should be food for thought. I looked into Rotax and it is designed to run at high rpm but you have a gearbox, coolant, and either dual carburetors or electronics as factor in possible failure. The UL Power is direct drive (lower rpm) and only electronics as factor outside basic mechanical engine failures. Rotax is high test MOGAS, UL 350iS also, the new flash update on UL350i will run on medium grade MOGAS.
Both engines do not require a header tank but you will need to install a fuel return line so using the header tank makes it easier than going to your wing tanks. Carbs will only have a flow through low pressure fuel pump the fuel injections engines use high flow and around 45 psi. Both like to have fuel pumps on the fire wall with negative pressure from header to pump. I think some folks in Texas are using header pump (Viking) to supply a UL power. If you go with preferred fuel system, you need to run at minimum 7-8mm fuel line. That is 5/16 minimum. I'm running aluminum tubing with 'rubber' ends connecting header (both return and feed). And 'rubber' ends from aluminum tube to fuel pump and from engine return to tube. I'm having blanks made to cover the old in tank pumps and upsizing the feed and return (I have the vertical cylinder style header with main fuel input and vent lines on top - engine feed on bottom). I will resize and tap one vent line on top for fuel return and use the remaining vent line Y'd to both wings). Get rid of the feed manifold, high pressure fuel filter, and consider making a standpipe on the feed line from header which will ensure any water that makes it from the wing tank to the header is not going into the engine (going to braze a brass pipe about 3/4 inch into the bottom fitting). Give a little unusable fuel but the drain will show any water or impurities on sample. It's up to you for fuel lines, but I'm running new ones from header to firewall with 3/8 (9.5mm) as the min. I still have a month plus of work on removing the wiring harness (I buried to much behind the instrument panel and with full shelf - bad planning on my part) and installing the UL Power.
Have fun,
Dave aka Blackie
-
Permalink Reply by charlie rosenzweig on
-
I believe it is important for all of us to share important factual information. If we can share information with each other and keep the blame game comments limited, we will all be better off.
I have read of a second PSRU flange failure, this one on Eric Millers plane. I have not talked with Mr. Miller and I hope he would be willing to share his information publicly. There are pics of both flange failures that have been shared publicly.
There have also been penetrating dye tests on these parts that revealed other cracks that with the naked eye would not have otherwise been seen.
I hope both Jan, (owner, manufacturer) will post here again on the Miller case. I know he improved upon the engine/crank flange and maybe there is some merit to an improved PSRU input flange as well.
Let's all have a civil and respectful Diaglog with intent to help each other so we can make informed decision on how best to move forward with what we know.
There are 3 pics below that I hope will post OK
Flange%20failure%20of%20both%20Miller%20and%20Hubelbank%20flanges%2...
eric%20miller%20dye%20showing%20second%20crack%20mark%20up.jpg
-
-
I just got an email from Jan, and he shared that both the Miller and Hubelbank were 110 set ups......
New from Zenith:
Classified listing for buying or selling your Zenith building or flying related stuff...
Custom Instrument Panels
for your Zenith:
Custom instrument panels are now available directly from Zenith Aircraft Company exclusively for Zenith builders and owners. Pre-cut panel, Dynon and Garmin avionics, and more.
Zenith Homecoming Tee:
Flying On Your Own Wings:
A Complete Guide to Understanding Light Airplane Design, by Chris Heintz
Builder & Pilot Supplies:
Pro Builder Assistance:
Transition training:
Aircraft Spruce & Specialty for all your building and pilot supplies!
How to videos from HomebuiltHELP.com
Developed specifically for Zenith builders (by a builder) these videos on DVD are a great help in building your own kit plane by providing practical hands-on construction information. Visit HomebuiltHelp.com for the latest DVD titles.
© 2024 Created by Zenith.Aero.
Powered by
