Yamaha RX1 Engines

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Posted

Well....should have listened to you guys.

The sled I had my eye on, got sold out from under me. I spent 3 weeks setting up ...and

one weekend, driving all over creation...and in the end...nothing.

So...I called Jim in Ballston Spa....and he is hooking me up!!    (Thanks Y-fox)

He is meeting me half way...next weekend...How cool is that !

Had my last flight on skis, Monday....just snuck that in....Took it into the hanger...Sat up my X-Y axis laser... and took some measurements.

First thing I noticed was FW to prop hub was under 24"...Everything I have read...says the RX1 is 27 +   Can you say cowl Mod...!!!

Everyone is going with straight through thrust line...Right?  No 3 degree offset, like the 582....(I could have missed something...)

I have been flying this 582 grey head and have just over 100 flawless hrs on it... Am thinking of selling complete FWF (except C box ) of course :P  

Motor mount, cheek radiators, Hac-man system,  exhaust....Everything...mounted...ready to Bolt on. Somebody should want that...

John O

 

 

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Posted

Just so you know, it wasn't me. :)

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Posted

Congrats John!  Welcome to the club!

Glad to hear of another good experience with Jim at Spa City Parts.  Seems like a really good guy.

And  I'm sure youve seen Jaed Paynes post here "My Mk4" where he put the Yamaha in his avid.  As far as cowl mod ideas I think he might be able to give you some ideas on solutions.  The only thought I have for you is that the stator cover is rather small and protrudes the farthest into the firewall.  If there were a way to make a FW cutout and allow for that you would gain 2-3" aft engine placement or so.  Probably unlikely but when you get the motor you'll see what I mean.

As far as engine angle I chose to give it a tweak to the left, mayne 3 deg or so but I really couldn't find much reason or necessity in doing that after posting up the question to the group here last year.

Please do start a new post of your conversion when you get a minute!

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Posted

Me_and_RX1_Jim.thumb.jpg.99c805c6a444588  Well....here it is. My RX1 in a  bucket. This is me (on the left) and Jim from Spa City. We met in the Bass Pro parking lot.

I think this will be my opening pic for my build thread (yet to be named). Mostly writing this to say what an absolute pleasure

it was to work with Jim, and him getting me this motor. His business is getting crazy, and it couldn't happen to a better guy.

Being honest and straight forward...is everything..to me, at least..and it shows, and is paying off for Jim. He is getting

overseas calls for motors. So if you need an RX1 or Apex motor....Call Jim...607-329-8676

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Posted

Buying a motor in a Bass Pro parking lot could end up being a very expensive trip. :)

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Posted

Buying a motor...for an Airplane...in a Bass pro parking lot...Who Would Do That?   :lmao: We all, had a good laugh over that.

You are so right....While I was buying a motor... the little lady, was bringing out new tile for the kitchen...

from the Lowes next door. What happened to retirement? Working on MY projects...All that good stuff????   Sorry...a little vent ...John O

 

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Posted

Walk inside the Bass pro and look at the prices on outboard boat motors.  It will make you feel a LOT better about flying!

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Posted (edited)

Easiest way is the "water trick".  Essentially you fill the clutch bolt hole with water, then find another bolt that has threads that match the larger threads in the center of the clutch (get a flashlight and you'll see them), wrap teflon tape on those threads, and thread it in....  the hydro pressure forces off clutch.

Here is a vid of one way to do it using a bolt from the sled.  I would weld the hole on the end of the bolt closed if I used that bolt, wrap teflon, tip engine up, fill water, thread bolt in, pressurize water... off comes clutch.

(And no that's not me in the video...  I'm a hell of a lot uglier than that)  :) 

 

Edited by Yamma-Fox
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Posted

Hello everyone, 

Well we finally melted out of the snowbank and are appreciating some warmer temps in the Cariboo Country. Winter is nothing but a faint memory and the skis have been replaced with the Tundra's. Here is a few clips of Willis flying the "Frozen Nose Fat Bastard" or as we now refer to it, the "Screamin Demon" on skis. The RX has performed well (outperformed the rest shall we say!!). Nothing fancy on the editing, I left the sound in original to give a better idea. 

https://www.youtube.com/watch?v=b1wamjY_-AE 

 

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Posted

What is the oil temp like with the RX-1?

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Posted

It has an oil cooler integrated on the engine, and also a big external tank (dry sump system).

 I plan to mount the oil tank up front by the cowl Inlet holes so that it gets extra air flow. I have not yet heard of anyone who has had issues with high oil temp.

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Posted

I am running at 257F which is a little on the warm side.

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Posted (edited)

I am running at 257F which is a little on the warm side.

Sorry.. forgot who I was talking to (someome already running a yamaha!)

I plan to run full synthetic Mobil 1 0w40 which can tolerate higher temps and avoid thermal breakdown of the oil.  I wouldn't flinch at running 257F

 

Screenshot_2018-06-26-14-24-25.png

Edited by Yamma-Fox

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Posted

What's the consensus on the final weight of the Yamaha? 

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Posted

Any flight reports on the new gearbox yet?

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Posted

257 degrees is a lot hotter than Ive ever seen on my oil. If I remember currectly it runs 10 to 20 degrees hotter than the coolant. I would check your plumbing to your oil cooler. The yamaha oil cooler seems to do a pretty good job. No flight reports on the new Apex gearbox yet. I have switched gear manufactures and I awaiting another set of gears to test the clutch. The first set that the clutch was tested with showed no visual wear except on the sprag races. The hardness was no where near what I specified. The new gear shop, hardening shop and grinding shop are locally and I can check up on and control quality standards a lot easier. 

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Posted

Excellent! Thanks for the update.

Clark

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Posted

As far as the weight question. There are so many weight numbers. Like fire wall forward installed weight or engine and drive weight so im going to assume that when you say"final weight" your asking the weight with everything on it istalled on the plane. Mine come out to about 160 lbs. Thats with carbs exhaust bottles radiator ready to fly. So if your familiar with the weights of the 912 it is about 15 lbs heavier. 

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Posted

On the oil temp discussion,  i bet it also would make a huge difference where you measured it right?

In the tank or coming out the bottom must be a lot cooler than if you were taking it off a tapped sensor in the oil cooler bolt or at the oil test port above the #1 exhaust port. 

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Posted

True, im not sure how much cooler it would be at the oil cooler. I measured mine at the oil filter. 

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Posted (edited)

Teal contacted me today with a report that a pinion shaft bearing began to fail on a (appox 200 hr) Skytrax RX-1 running an RK-400 centrifugal clutch.  

This event is noteable because it is very similar to one other case where the same problem was encountered  (also a Skytrax RX-1 w/ RK400, but with approx 110 hrs).

Other noteable facts include:  

-  Both failures suffered NO powerloss.  The bearing began to give out but the rigidity of the RK-400 clutch (mounted on the PTO) helped keep the clutch drum and pinion shaft centered and the gears remained "meshed" and running.  It appears likely that at least one of these two gearboxes ran for a number of hours in the partially failed bearing condition.

The problem (in both cases) was detected during a subsequent preflight by noting some side to side play in the clutch drum.

-  Also noteable is that there are many other setups nearly identical to this one (centrifugal clutch with similar hrs of use) which have had NO problems, and also there have been no reported problems while running the rubber flex drive ("hardy disc").

******UPDATE****

Analysis is back from the Rotax service center on these two gearboxes.  It was determined that the latest gearbox was assembled incorrectly during a gear set change (see pic 2 posts down), and that both gearboxes had the pinion bolt come loose during operation.  (that bolt in the center of the pinion shaft, bolt head located in gearbox, going out through to the coupling that connects to the clutch drum / hary disk)

When that bolt came loose, the pinion shaft  apparently "rode up" the gear teeth and rammed against the outer pinion bearing (in outer case), loading it axially which in time caused the bearing to fail.  Also the gear wear pattern on the second (improperly assembled) gearbox had the large gear scraping the case cover and the pinion bearing race.  Wear marks showed that the two gears in that one only had about 50% tooth alignment.

So it looks like the problems here have been isolated to improper assembly and also more noteably from the pinion bolt coming loose, so a couple unofficial recommendations are suggested from the shop to users of the c gearbox:

The pinion shaft bolt should be cleaned thoroughly and red loctite used during final assembly. (torque is 212 in-lbs)

When you have the gearbox apart to that point, the axial clearance of the pinion shaft should be checked.  This clearance is critical to bearing life and gear engagement.  In the post below I'll reference the service manual excerpt on how to make this check.

Additionally anyone running the Rotax gearbox can also make an easy preflight check to determine that the pinion bearings are in good condition.  This is a simple procedure where you reach in the access / cooling hole and physically push on the drum / hardy disk.  There should be no detectable side to side movement.

 

Edited by Yamma-Fox
Edit for final analysis.

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Posted (edited)

Reference post above,  here is the axial clearance measurent screenshot from the manual, along with a description of how I found to do it in an easier way:

For anyone who wonders the procedure for checking Rotax C pinion shaft axial clearance, here is a copy, but I found it easier to simply add a number of shims (I put in like 4), install and torque pinion bolt, then set the case cover down (without gasket).  The proper gap IS the .4mm gasket, so I measured the case cover gap without the gasket and removed a number of shims that measured the same (or slightly more) than the gap.  

Then I double checked my measurement by doing it the way described in the manual.  For my box I had a .44mm clearance with zero shims. 

I also think it is important, during reassembly,  to triple check that you don't have too many shims in by checking that the case cover actually still will contact (without the gasket) the case.  This ensures that you didn't add too many shims and have a binding problem when you bolt the cover on.

I'll re-check that at about 30 hours after break-in and predict that I may need to add one shim at that time.

FB_IMG_1530546670112.jpg

Edited by Yamma-Fox
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Posted (edited)

For anyone who might be following, I did an update 2 posts up on the c box that had a problem.

And here's a pic of what was meant by "improperly assembled".  Absolutely amazing that the gears and gearbox held up to 140 hp for 200+ hours with the gears barely even meshing like that!!

 

FB_IMG_1531073664799.jpg

Edited by Yamma-Fox
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Posted

I had a similar situation were the pinion screw came undone.It came to my attention when doing an oil change as there was a lot of metal on the plug.The shim(shims?) had failed due to the hammering at idle,it had been loose for so long the screw had a flat spot worn in the threads from rattling around.We cleaned it up and had a few extra eyes look it over.there was no gear or bearing damage visible.An oil change was done at 10 and 20 hrs with no metal visable on the plug.These boxes are tough!      The only giveaway the problem in hind site was a rough idle below 2000rpm and the start was a little slower.

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Posted (edited)

Just incase any one is following this thread, and not the rest of them, I have a C gearbox, 3-1 ratio with about 200 hrs on it that I might sell.  Send me a PM if interested. JImChuk

Edited by 1avidflyer

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