Oil Injection

[gyropilot]

I thought I'd show everyone a few pictures of the new oil injection system I added to the Rotax 503 on my Bee.

This is a photo of the oil injection pump on the pull-start cover, taken from the left-front of the engine. Note how far back the engine is from the mast to give adequate clearance for the pump. The ripple effect: Moving the engine back required new engine mounts, which shifted the CG back, which required the rotor head to be moved farther aft...

http://home.usaa.net/~gyropilot001/Injection/InjectionPump.jpg

This next photo shows the oil-injection pump control cable where it terminates at the pump. During the 1 hour engine break-in procedure a couple of weekends ago (I had the cylinders bored and installed new pistons/rings), I discovered after-the-fact that the end of this control cable (at the pump) had vibrated free of the bracket. This effectively lengthened the control cable, which in turn caused the pump to meter too much oil into the engine for a given rpm. The result was a little too rich fuel/oil mix and some excess carbon buildup in the cylinders. Not a problem for the break-in, and definitely better than having not enough oil.

You'll see I've added safety wire to prevent the control cable from vibrating free of the bracket...

http://home.usaa.net/~gyropilot001/Injection/ControlCable.jpg

Here's the oil tank mounted above the engine on the existing brackets which support the muffler. This is a Rotax tank designed to mount directly to the head of a 582 engine...

http://home.usaa.net/~gyropilot001/Injection/OilTank.jpg

And lastly, new vertical engine support struts. With the engine shifted back so far, these were added to give extra support to the rear of the engine mount.

Those of you who know anything about material stresses and metalworking will notice a big fat design NO-NO on the strut end fittings I machined. They're machined out of 6061-T6 rod. Can you guess what the problem is?

My excuse? I guess I just got in a hurry when making these parts and it didn't dawn on me what I was doing until they were finished. I plan to replace them at some point before they become a problem.

http://home.usaa.net/~gyropilot001/Injection/EngineSupportStruts.jpg

Regards,

John L.

[Brian Jackson]

Square sharp corners! :eek: . Nice installation though. I've always admired your machine. Hope my Bee turns out as nice. Thanks.

Brian Jackson

[gyropilot]

Square sharp corners! :eek:
Winner! Winner! Winner!

John L.

[CLS447]

Really nice work John! I was gonna say about the square cuts, but I wasn't fast enough. Why no washers under the nuts & bolts? Oh never mind ,I see them now , at least under the nut.

BTW, how are the ends attached to the tubes?

[gyropilot]

Why no washers under the nuts & bolts? Oh never mind ,I see them now , at least under the nut.

BTW, how are the ends attached to the tubes?
Chris,

Washers aren't required under either a bolt head or nut... they're normally used for spacing as needed up to a maximum of 3. However, I do prefer to use at least one washer under the nut to prevent the nut from turning directly on the part being held. That way the cheap washer takes the repeated wear of assembly as disassembly.

The machined ends are epoxied about 1.5" deep into the tubing. They're under compression so pull-out shouldn't be an issue.

Regards,

John L.

[GyroRon]

That Rotax Oil line hose won't last long. A year or two before it starts to leak through.

Man alot of work to add something else to fail John!!!!

[gyropilot]

That Rotax Oil line hose won't last long. A year or two before it starts to leak through.Ron,

Thanks for the warning about the oil line hose... I take it you're talking about the large black braided cloth covered supply line? I replace all the hoses on my gyro once each year during the annual condition inspection, or at least every other year, so this shouldn't be a problem.

Man alot of work to add something else to fail John!!!!To each his own.

John L.

[Doug Riley]

John's right that those down-struts he's installed will generally be loaded in compression. Certainly they will be in a tailwheel-first landing. There are times, however, when this particular component of a gyro is loaded in tension.

For one thing, engine torque can put one of the pair in tension. The torque will tend to rotate one side of the engine up, and that's the side that'll be in tension. The torque figure that matters in this case is the torque at the PROP, not at the crankshaft. You need to multiply crankshaft torque by the redrive ratio to get prop torque. This figure is then the average torque. Peak torque pulses can be 2,3 or more times the average.

Also, thrust can put both legs in tension. On a Gyrobee like John's, the Rotax gearbox is down and the cylinders are up. This puts the engine mount right on the prop thrust line, with very little tendency to fling the back end of the engine up or down as throttle settings change. On other engines where the redrive puts the prop centerline above the mounts, the down-struts may go into tension at high power settings. That's the way it turns out on the Rotax 912 and 914, for example, if you use the bed mounting option.

It's safest to design for loads in both directions.

[Brian Jackson]

Forgive my ignorance as I am but a student here on this forum. If the Rotax 503 is a 2-cycle engine, what is the purpose of an "oil injection" system? I'd always assumed the oil was mixed with the fuel before filling the tank. Or is this new oil system to lubricate the engine's internal parts... bearings, etc., and separate from that of the fuel or a dedicated oil pan?

I really know too little about engines, so I'm asking to learn.

Thanks,
Brian Jackson

[gyropilot]

If the Rotax 503 is a 2-cycle engine, what is the purpose of an "oil injection" system? I'd always assumed the oil was mixed with the fuel before filling the tank.Brian,

The oil-injection system is simply an alternative to pre-mixing the 2-stroke oil directly into the fuel. With this system, 2-stroke oil is injected by a metered pump into the intake manifolds instead of adding it to the fuel. Rotax currently provides an oil-injection system as standard equipment on all new 2-stroke engines.

Oil-injection is thought to have several benefits over premixing:

1. The fuel to oil ratio is varied by the metering system from 70:1 at idle to 50:1 at full power. This is said to reduce emissions and carbon buildup in the cylinders as the engine doesn't need a 50:1 ratio at lower rpms, but does at higher rpms.

2. Unmixed fuel will stay "fresh" longer than premixed fuel (retain octane longer).

3. The presence of alcohol in fuel becomes less of a concern, because it's primarily the reaction of the alcohol when mixed with the oil in the fuel tank that's the problem.

4. Refueling becomes less of a chore... especially when cross country flying. Just fill up the fuel tank and make sure there's 2-stroke oil in the oil-injection tank. No more measuring, pouring, and shaking!

However, premixing is still preferred by some due to concerns over possible failure of the oil-injection system. Failures are rare, but like anything else, it could happen. It's an individual risk assessment.

I bought my injection pump from someone who removed it from a brand new engine.

Regards,

John L.

[cgmg]

John,

I can sympathize with your engine remount issues. I just mounted our new 503 on our Air Command, and had to move the engine back 1" for clearance for the oil injection. It was a pain, but in the end, I think it will be worth it due to the benefits of oil injection. Your installation sure looks a lot nicer than mine!

I'm having trouble with the cable ferrule(?) not wanting to stay centered in the pump arm, still working on a way to keep it centered. Got two things to try, one is e-rings on either side of the cable, the other is to add a little solder to each side of the cable. Trying the e-ring first, unless anyone has a better idea.

Ron,

I'm glad you brought up the hose issue. Fortunately for me, the hose wasn't long enough for my setup, so I replaced it with a better hose from my NAPA buddy. I still will probably replace it every other year. I do all my fuel lines every year, but believe every two years will be often enough for the oil hose.

[GyroRon]

I guess I was just being Mister Negative.... The hose should last at least a year or two and probably alot longer before it goes bad.

Most of the hoses on ultralight type aircraft go bad by becoming hard and easy to break and crack. The oil injection hose doesn't do this. It stays soft and useable. But at some point down the line the hose will begin to seep out oil and will start to make a mess on the gyro. I have seen it on every rotax using this hose that is more than a few years old with the original hose. So there is no real need to replace it every year, but do know that it will leak not harden.

BTW I got a brand spanking new Rotax 447 in my living room. Came today from Lockwood and I get to install it on the Challenger ultralight living in my hangar this weekend. It did NOT come with oil injection....

[Udi]

Viton tubing will last a long time (probably longer than the engin) in low-pressure oil applications. They are expensive, but worth every penny.

Udi

[gyropilot]

BTW I got a brand spanking new Rotax 447 in my living room. Came today from Lockwood and I get to install it on the Challenger ultralight living in my hangar this weekend. It did NOT come with oil injection....I stand corrected:

Every new 2-stroke engine supplied by Rotax *except* the 447 comes now with an oil-injection system as standard equipment.

Regards,

John L.

[gyropilot]

I'm having trouble with the cable ferrule(?) not wanting to stay centered in the pump arm, still working on a way to keep it centered.I noticed the very same problem with mine.

The CPS catalog calls this little ferrule an "Oiler Swage." Interestingly, they list two different sizes: one 5/16" OD x 3/8" wide for the 503 and one 1/4" OD x .260" wide for the 582-618.

In my case, I simply squeezed the little u-shaped ears of the pump arm together *slightly* so there was no chance this swage could come out on one side or the other (thus jamming in the pump arm). Look closely at my photo in this thread and you can see the slight bend.

A better more elegant fix might be to have some sort of tiny nylon bushing around the cable just resting on the top of the swage (which would keep the swage centered between the ears of the pump arm). Or you could make a wider swage and install that... but that would mean replacing the entire inner cable (what a PITA).

Good luck,

John L.

[Brian Jackson]

Can the 447 be fitted with one as an add-on? Or does the design not permit one? Seems like a great idea the more I think about it.

[cgmg]

John,

I tried bending the ears like you did, but it didn't seem to help, and I didn't want to take the chance of it getting jammed at an angle.

I tried several sizes of e-clips, and found a set that fit snugly on the swage. Once I got them over the swage, I used needle-nose pliers to squeeze and position them to the outside of the swage. Now the swage is firmly centered in the arm.

I agree that working with the oil injection cable is a PITA! I've had the swage in and out of the arm half a dozen times, for one mistake or another. That may be why bending the arm ends in a little didn't work for me. I suspect that I've gotten it enough out of whack from side to side that the swage doesn't rest evenly in it from side to side. But I will do everything I can not to have to remove the cables, and open up the splitter again. I wouldn't wish that experience on anyone, unless they're very good at making their own cable ends.

By the way, if you bought the CPS oil injection cable, how did you get the oil injection cable end into the splitter? We had to melt the solder on the swage end, pull the cable out, and then build the splitter. Then we had to re-solder the swage end on, after threading the slightly bent cable through the swage, and getting it bent over properly again. That was a truly frustrating experience.

The bad news is that once we got all that done, I noticed two cracks in the outer skin of my Brock throttle cable, which means that later this winter I have to repeat the oil injection cable nightmare again.

Enough whining, I believe I'll be able to break ground tomorrow, it's supposed to stop raining late morning.

[GeneWeber]

Hi Folks,

John’s oil pump is from my new 503. Let me make it very clear that I think very highly of John. He’s talented, knowledgeable, and a genuinely nice person. We’ve exchanged numerous email and he’s helped me out on several occasions. More than once I’ve wished he didn’t live on the other side of the country so I could meet him in person.

That said, I’m concerned about the modifications for the Bee that inexperienced guys are so quick to embrace. Take a lesson from John. First he built a relatively stock Bee and learned to fly it well, now he’s modifying it. He’s also doing it one mod at a time. The stock Bee is a proven design. When I first approached gyroplanes I was fired up to create something unique. My thinking was “I’m an engineer, I’ll learn some basic principles and start creating!”. Fortunately some wiser and more experienced people talked me into sticking with proven stuff. I also started to realize how little I knew. There aren’t just a handful of fundamental aerodynamic principles; there is a large body of knowledge (aerodynamic, mechanical, structural, materials, construction) that takes time and experience to acquire. To be frank, most of us never will. Ignorance of a key bit of trivia could kill you.

My biggest concern with much of what I read here lately is added weight, and specifically where it’s placed. Ralph’s Gyrobee is based pretty closely on Martin Hollmann’s HoneyBee. He’s been put down on this forum, but Martin Hollmann is an aerodynamic engineer with years of practical experience. The CoG on a stock Bee based on most reports is a couple inches below the thrust line. Consider what happens to that when you add heavy shocks below the thrust line, engine supports below the thrust line, disk brakes down low below the thrust line, more fuel below the thrust line. John is smart enough that I’m sure he’s rechecking his CoG relative to his thrust line. On the other extreme was a post several months ago where someone built a “CLT Bee” by completely reworking the frame to something like a Dominator set up. If the stock Bee is only off of CLT by a couple of inches, raise the seat (yes, you need to consider not making your shoulder harness mount too low so you don’t break your back in an accident), and add a Wunderlich pre-rotator which will give you some pounds up high. I’ll bet you my Bee comes in pretty close to CLT when I’m done, without any major modifications.

I think John is probably rare in that he flies his Bee cross country. He’s outfitting it for that, and that’s fine. As already noted he’s bright and experienced. But if you’re new at this, consider what the Bee was designed as, an ultralight. My Bee will be registered experimental but won’t exceed ultralight by too much. You don’t buy a 100cc Honda and try to turn it into a GoldWing highway cruiser. The GyroBee is a proven cheap entry level gyroplane. If you don’t want to start small and move up later, buy something designed for more, like a Dominator.

Please take this in the manner intended, and also please forgive me if I come off too preachy. I’d just hate to see someone get hurt or killed needlessly. Just building a relatively stock Bee and flying it is going to be the thrill of a lifetime.

Sincerely,

Gene

[Brian Jackson]

Great post, Gene, and I wholeheartedly agree. That's part of the charm of the Bee is it's simplicity and safety if built stock. I think it's great that mods can be made for various reasons, but concur that newbies like me should stick with known values.

Thanks,
Brian Jackson

[GyroRon]

Gene, good post. It is bured here in this engine related thread, so I started a new thread with your advise. It is in the Builders Corner section.

[GeneWeber]

Hi Brian & Ron,

Thanks. I debated posting it, so I’m glad it was taken in the spirit intended.

Best Regards,

Gene

[Jerseywing]

John,
If the struts are an add to the existing structure to beef it up a little then I think the ends will be fine. They look pretty beefy and will have little to no load on them so IMHO they'll be fine.
BTW beautiful job...
Mike

[CLS447]

What happens to the pics in these old threads?

[Dirtydog]

Don't know what the problem is I can't see the pictures at all!

[CLS447]

Chris, You would love the pics that John had posted here! He was an artist!

I wish there was a way we could see them again !

[Resasi]

Our 503 arrived with oil injection however the position of the engine on the Hornet meant taking it off as we wanted to avoid the various changes that we would have to do to keep it on.

I had asked my son to inquire whether it was possible to relocate it, those pics may well have answered my question. Have read the various pros and cons and would fit if we can place the oil pump somewhere else, although it still sounds as though one has to move it back to do even that.

[CLS447]

Resasi, what pics are you referring to ?

The first post in this thread.......can you all see the pics or just little red X's ???

[DennisFetters]

I posted this before, so I'll post it again. If you want to read more posted about what I wrote on this, then just do a search for my posts under "oil injection" and author DennisFetter.

I just hate to see new people in this sport starting off wrong by taking bad advice, so here are the facts again, take it, leave it or argue it as you wish;

""It's no wonder people complain about Rotax engines failing and not lasting more than a few hundred hours. The oil injector on the Rotax was the second best thing they did to improve the reliability and longevity of their engines. The electronic ignition was the first best thing.

The oil pump will not just fail for no reason.

If you don't use the oil filter than your oil pump will fail, so always use a filter.

If you don't use the proper metal screen filter, then your oil pump will fail, so only use the right filter.

Never mix oils. Find an oil and stick with it. Pennzoil 2-stroke is great, readily available at any Big-Box-Mart or Wally World. It's a mineral oil so it provides rust protection and it's affordable, most importantly predictable.

If you use a pure synthetic, poor you. If you use a synthetic mineral mix OK, but stick with it and when you run out, you're grounded until you're shipment arrives. Do not mix another brand of synthetic or mineral with another brand. There are additives in synthetics that will not allow them to be mixed with just any other oils. Mixing incompatible oils can cause a slow reaction and congeal the thickening agents in the oil that will clog your filter and pump, causing engine failure.

Never run your EGT's in cruse flight below 950F. 1050F is even better.

The fact is that 98% of all Rotax engine failures are due to improper installation and/or improper care and feeding, or not knowing the difference of whats right or wrong.

The oil injector on the Rotax engines is a must, and anyone not using one, I can only think that they simply do not understand it's importance. Think about it.....

What is the reason oil protects the engine? Magic? No, it's viscosity prevents the metal from touching, simply speaking.

What works well to clean up an oily mess? Gasoline. Why? Because it brakes down the viscosity of oil.

So, mixing oil with gas dramatically reduces the oils viscosity, lowering it's protection capability. That is the simple reason why a Rotax engine with an oil injector will last 4 times longer than one without.

As I said above;

There is no good reason not to use the oil injector, and there are many good reasons to use an oil injector.

1. Better lubrication from higher viscosity oil droplets.

2. Uses much less oil then mixing, reducing pollution, carbon buildup and smoke.

3. Oil injected droplets tend not to burn as much, or in the bad way that mixed oil does. Mixed oil burns dry and causes buildup, while injected droplets tend to stay wet and burn in the exhaust system, clogging rings to a much lesser degree.

4. You can take much longer trips using oil injection, because you don't need to add oil for up to 10 fill-ups, while you need to mix every time you fill-up.

5. You don't need to carry oil with you on cross country flights when you fill-up at other locations, mixing oil you do.

6. You can go up to 10 fill-ups before having to remember to add oil when you have an oil injector. You have to remember every time when mixing.

7. I have had only 2 Rotax engine failures out of the thousands of hours I have flown gyros. Both were due to not mixing the oil with the fuel. I have never had a single engine failure since I started using oil injection.

Why would anyone not use oil injection? I guess because they simply choose to ignore the facts.

Please, you new guys that are just starting, please don't follow the advice of someone when they come up with some rare reason why they choose not to use an oil injector. They are simply giving you bad advice.

I had a buddy killed on a motorcycle because the helmet he was wearing got tangled on a tree branch and broke his neck. But, does that mean that helmets are bad and should never be used? Of course not.""

I'll add this, no matter what the facts are, if someone chooses to ignore them, then........ well, you can lead a horse to water, but you can't make it drink.

[Dirtydog]

I am not using my Oil ing. on my motor. I don't trust them at all. I have seen filters get cloged up because of the oil and hose come off. This was all on golf cart motors.
It just to much motor to trust.
But it might have been a lot of things I did wrong!