Viking 90 engine video.. your thoughts?

Discussion in 'General Auto Conversion Discussion' started by pfarber, Aug 24, 2019.

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1. Aug 24, 2019

pfarber

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I've noticed the following 'trends' from several 'auto conversion videos' and I think it should be pointed out.

PLEASE NOTE: This is for (my) educational purposes, when I was in A&P school there were a lot of extra steps that auto mechanics never, ever had to deal with. Conversely, with an auto engine there are a few things that are not done on on them that I think would be mandatory for flight.

NOTHING WAS LOCK/SAFETY WIRED. Big ass drain bolt on the bottom of the PSRU? Kinda important that it doesn't come out. Not safety wired (or even a lock washer). Oil filter? Not safety wired. There were also very few witness marks on bolts.

The 'Aircraft Spruce quality' cable mount was a simple metal crimp type, not rubberized.

The mounting bolts of the PSRU did not protrude past the lock nut (some did, most looked flush). I remember from A&P school that you needed at least 1-2 full threads past the nut. MANY bolts suffered from this 'to short' issue.

From The AMT General Handbook page 7-46

After the nut has been tightened, make sure the rounded or chamfered end of the bolts, studs, or screws extends at least the full round or chamfer through the nut. Flat end bolts, studs, or screws should extend at least 1 ⁄32 inch through the nut. Bolts of 5 ⁄16-inch diameter and over with cotter pin holes may be used with self-locking nuts, but only if free from burrs around the holes. Bolts with damaged threads and rough ends are not acceptable. Do not tap the fiber locking insert. The self-locking action of the elastic stop nut is the result of having the bolt threads impress themselves into the untapped fiber.

Do not install elastic stop nuts in places where the temperature is higher than 250 °F, because the effectiveness of the selflocking action is reduced beyond this point. Self-locking nuts may be used on aircraft engines and accessories when the engine manufacturer specifies their use.

Yet the Viking engine uses elastic stop nuts about 4 inches from the exhaust manifold.

Almost none of the wiring harness on the engine was protected, either with tape or plastic conduit. No stress/strain relief on most connectors to sensors or the ECU.

Does anyone see any other 'best practices' that were not performed?

Again, I have nothing against this company, they just happened to have a video that showed a lot of the engine.

2. Aug 24, 2019

BJC

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I personally know several people who did business with the previous auto conversion business owned by Viking Aircraft Engine Company’s owner. They would suggest that a best practice would be to steer clear of that man’s business.

BJC

3. Aug 24, 2019

pfarber

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"Does anyone see any other 'best practices' that were not performed?

"Again, I have nothing against this company, they just happened to have a video that showed a lot of the engine."

These should be the topics of the thread, not attacks. If the setup is bad, please point out why. I mentioned several things, did anything else go un-noticed?

Don't start attacking the company, or the owner. This is the 'general auto conversion' forum. Not the BBB or yelp.

4. Aug 24, 2019

Victor Bravo

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Then perhaps the title of the thead should not have been "Your Thoughts".

However, in fairness, I do agree that perhaps this topic should be split into Viking Engines and Viking Business.

5. Aug 24, 2019

Daleandee

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I'm not interested in this engine at all and will refrain from comments on the company ...

I don't care for barbed hose fittings on pressure lines whether fuel, oil, or coolant. I'm certain they have been proven to work but it's just something I personally would avoid.

Dale
N319WF

6. Aug 24, 2019

TFF

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Auto mechanics is taught just like A&P. People who love cars or airplanes love the process and machines more than the job.

What is as manufactured in A&P world is unchangeable by the A&P unless they change the manuals so in the airplane world you are supposed to blindly keep the flaws flying until the manufacture fixes it. The General A&P handbook only applies if there is no manual to follow from the manufacturer. I know I am being overboard for the effect.

Flaws I see. Elastic stop nuts. While placement is ok but not stellar. I think they are far enough away to not melt. He did use elastic stop nuts to hold his gearbox on. Something that can not shake loose in flight at all. Safety wire or cotter pins, please. Barbed connections. Another plenty on older airplanes, but they are all low pressure connections. High pressure fuel or coolant lines should be better quality. I would also get rid of the muffler right there. Just a big chunk of heat.

I actually think car guys would go straight to AN hoses, at least anyone who reads Hot Rod. Reliability for airplane is just like race cars. Similar dangers when something goes wrong. Regular auto or airplane mechanics just follow the rules. Car enthusiasts are in line with home builders.

7. Aug 27, 2019

pfarber

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I saw and agree that the barbs are not great, but coolant lines are not high pressure, and as long as the hose is routed correctly I don't think its a show stopper. One reason I like the idea of synthetic coolant.. no pressure at all. For a radiator coolant line I'm on the edge.. there is no AN fitting that would be of sufficient diameter (is there??) For oil lines yes, AN fittings on AN hoses (that's a $50-75 hose now). Would I use barbs? No, but I would use the proper beaded fittings and rubber hoses with clamps. For the gear box elastic stop nuts are an approved fastener for use by the FAA. MS20635 is for < 250F. They have metal lock nuts AN363 good for up to 550F which is what SHOULD have been used. What I saw that I didn't like was that the bolts were not long enough, and without threads for the insert to grab, it will come right off. I'm not sure if safety wire would be better, as you typically don't safety wire a nut/bolt combo. You use a drilled bolt and a castellated nut or a self locking nut. I hope someone else can find a different video so we can see what changes we can make to improve the operation of conversions into airframes. Maybe one of the$40k+ v8s that seem to be popular.

8. Aug 27, 2019

TFF

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For the case bolts I probably would have machined it for the bend tab safety or the cotter pin option. They have to be positive safety. Bolt bolt head to bolt head. Nut to nut. Both sides. Cage the bolt heads. Something. I’m ok with odd if still reasonable. A lot of this is because it is a homebuilt engine project. No vetting is required. A lot is on the installer to fix their problems. It’s actually why the FAA allows the hobby. It is really a hard hobby to be a consumer driven hobby. Some companies think they are but most would fold with any real challenge. Vans is probably the only company that could hold their own. You might be buying something, but you not buying anything with any appreciable running. Good or bad; it’s an experiment.

9. Aug 27, 2019

Himat

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I do not know modern car standards and I have not worked that much on modern cars. Anyway, I am not sure if the pictured engine is up to say Toyota manufacturing standard. Still your question about safety wire, castellated nuts and hose fittings can be turned around.

How many castellated nuts and how much safety wire do you see on a modern car?

How often do screws work lose on modern cars?

Could it be that modern car manufacturing practice is as durable or better than A&P best practice?

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10. Aug 27, 2019

litespeed

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How do you lock wire a oil filter?

11. Aug 27, 2019

BJC

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12. Aug 27, 2019

litespeed

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Thanks for that BJC,

However the auto ones don't have a flange to lock wire to, or are they available like the aero ones to suit?

13. Aug 28, 2019

Daleandee

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I use K&N oil filters and they do have a welded nut on the top that allows them to be safety wired:

Do not use the nut to tighten the filter as it should be used only for removal if needed.

If your filter of choice does not have a lock wire provision you could always use a hose clamp around it to fasten the safety wire to. I don't go crazy with safety wire but the oil filter and the drain plug are items that I insist on safety wiring.

Dale
N319WF

14. Aug 29, 2019

pfarber

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Safety wire is standard in many industries that require as much reliability as you can throw at it. Its a cheap and easy method to reduce failures.

Just about any suspension part has cotter pins or lock washers/nuts. If its subject to vibration/shock it has a locking device on it. Ever see and engine's main bearing caps? Or con-rods? FWD drive shafts on trucks? Most FWD hub nuts are one time use. Also in cars they can use lock washers much more freely. In AC not so much , the steel lock washers can rip clean through Aluminum if torqued. To use lock washers in AC they usually need a steel flat washer under them.

Remember, car motors are not designed for the same environment. Take a plane up to 10,000ft the air temps can easily reach 20F, how cold do you think the air is when its moving at 120kts? Minus how many degress??

15. Aug 29, 2019

rv7charlie

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Uh, 20F.
edit; wasn't at a computer for initial post. You're probably thinking about wind chill, but once an object is down to ambient temp, it won't get colder than ambient. So 20F would be 20F wind speed zero or 120.
https://en.wikipedia.org/wiki/Wind_chill

Last edited: Aug 29, 2019
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16. Aug 29, 2019

Himat

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I have seen a lot of lock nuts, loads of chemical thread lock, lock tabs, depending on industry lock washers, some lock screws, but on anything produced in volume not much lock wire. I do think I see parts assembled by special tools pressing, swaging or crimping the parts together more often than safety wired.

The most common use of cotter pins I see are on bow shackles of the kind where shackle is not threaded and a separate nut is secured with a cotter pin. This is also a good example on where to use cotter pins and safety wire. A bolt laded in shear where the nut only keeps the bolt in place and take no strain. With a screw laded in tension, the tension is already lost when the safety wire or cotter pin stop the rotation.

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17. Aug 30, 2019

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