Yamaha RX1 Engines

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Posted (edited)

I was in the Army with a WW2 P38 pilot - He said that there was so little heat in the cockpit that he would wrap a sheepskin flying jacket around his feet and they still froze.  EDMO

I watch alot of those old war stories on tv and see how rough it was  Really makes me respect what you men did for us. You had to be one tough SOB to fight back then.

Most had no choice - It was either do or die, and a lot of them died trying to protect others.  Vets are tough "SOBs"!    Fuck the rich spoiled NFL players who wont even stand for them and our National Anthem - No football on my TV, and I wont spend a nickel on their jackets and caps!   I have a lot more respect for the slaves and others who fought to free America and to keep it free than I have for those ungrateful bastards!  

(My wife says that I am a gentle sweet person until someone kicks a Vet, then "All Hell is coming out"!).   

Guess I wasn't through with my rant - I wanted to say, "Fans" of those money-players think the players are doing this for them, but all they are playing the game for is MONEY!   EDMO

 

Edited by EDMO
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Posted

Being a Vet. Myself I appreciate that and feel the same for my Vet. Brothers and Sisters. 

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I've always wondered about the delivery motives on those aircraft.  If I ran the effort to equip Stalin with some airplanes it would make sense to me first to send all my very best pilots into combat in Europe and the Pacific.  Then, wanting to save as much money and time as possible I would build a string of airports at distances apart from each other that closely aligned with the range of the aircraft being ferried to Russia, then I would take those pilots that weren't especially fit for combat and put them in the cockpits of airplanes that I didn't particularly want and send them to their dooms over the top.  I imagine that that scenario is probably a factor; not the factor. 

A careful read of any one of dozens of histories of command decisions during WWII will suggest a peculiar cold efficiency to their methods.  Also, all of those airplanes were widow makers.  The only ones the pilots (several of whom I knew personally) really liked were the P-51 and the F-6.  Corsairs, P-40s and many others were horrible beasts. The P-38 early was a death trap until they figured out counter rotating props to eliminate the critical engine.

I was in the Army with a WW2 P38 pilot - He said that there was so little heat in the cockpit that he would wrap a sheepskin flying jacket around his feet and they still froze.  EDMO

the poor Russian pilots must have had a hard time on long flights Ed

Hey is the avid fox p39 forum:)

Nah, for those Russian pilots ANY heat was like a nice sunny day at the beach.

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Posted (edited)

I was in the Army with a WW2 P38 pilot - He said that there was so little heat in the cockpit that he would wrap a sheepskin flying jacket around his feet and they still froze.  EDMO

I watch alot of those old war stories on tv and see how rough it was  Really makes me respect what you men did for us. You had to be one tough SOB to fight back then.

Most had no choice - It was either do or die, and a lot of them died trying to protect others.  Vets are tough "SOBs"!    Fuck the rich spoiled NFL players who wont even stand for them and our National Anthem - No football on my TV, and I wont spend a nickel on their jackets and caps!   I have a lot more respect for the slaves and others who fought to free America and to keep it free than I have for those ungrateful bastards!  

(My wife says that I am a gentle sweet person until someone kicks a Vet, then "All Hell is coming out"!).   

Guess I wasn't through with my rant - I wanted to say, "Fans" of those money-players think the players are doing this for them, but all they are playing the game for is MONEY!   EDMO

 

Now I am finished!   I'm going to have a nice day without watching any "games".   ;<)   EDMO

Edited by EDMO
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Posted

You missed a wild ending to the Vikings game..... They make me so mad, I don't know why I cheer for them.... JImChuk:wacko:

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Posted (edited)

You missed a wild ending to the Vikings game..... They make me so mad, I don't know why I cheer for them.... JImChuk:wacko:

I didn't know that Norway played ball?   Their fast invasion boats were pretty cool.   ;<)  EDMO

Edited by EDMO
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Posted (edited)

Ok guys, finally got to that rx-1 test running with 1 (and 2) of the 4 cylinders down:

Yamaha RX-1 Performance Test on 3 cylinders:

Ok, so part of my decision to go yamaha was that (since it does not have dual ignition) it would perform adequately on 3 cylinders if one were lost to a bad coil, spark plug,  carb blockage, stuck/burned valve, etc.

So I put the theory to test out on the snow today by pulling a coil lead off a cylinder.

Results were better than I expected,  with an easily started motor, good idle, and an estimated 80 hp output.

Details of test:  (All speeds are off the snowmobiles "dreamometer", which are accurate in comparison to one another, but all read high by approx 8%). 

2005 Yamaha RX-1, 30 deg F day (heat wave here in MN!) through 2" of loosely packed snow.  Top speed 78 mph with the #2 cyl coil unplugged.

That compared to a MUCH lighter 2012 Ski Doo 600 ACE (60 hp 4 stroke).  Top speed 64 mph.

For the 100 lb heavier RX1 to go 14 mph faster than the  ski doo in loose snow would probably take between 15 to 25 more HP.  (Note that a lighter 90 hp ski doo I ride occasionally would have gone about 85 mph in those conditions) 

So I am happy in those results.  The engine sounded and ran surprisingly well!  And 80 hp would be plenty to fully operate my kitfox 5 which was designed to use an 80hp rotax 912 as the normal powerplant.

Conclusion IMO is that dual ign is great, and would be preferred.... but it does only cover ignition redundancy.  I prefer the yamaha (with it's extra power reserve) which could carry the day very well with ANY failure of power output from a single cylinder.

 

Running on 2 cylinders test:

Test results running on 2 cyls (#2 and #3 coils unplugged):

I'm really surprised by this one,  started right up, idled fine on the all cyl idle stop, ran 53 MPH down the trail!!

That's gotta be 50 HP!

I was guessing it would have done less, but that would keep me in a gentle drift down in the plane... giving 10 times the options and time for a emergency landing.

Really happy to see it perform like that!

Edited by Yamma-Fox
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Posted

And hey Leni,  you're a sled guy too.

Can you look over my estimations here and give your opinion on their accuracy?  Thanks

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Posted

You guys got me sooo fired up about this motor, when I went through this thread, a couple months back.

Since then, I have been checking on sleds to buy...and all the components needed for such an undertaking.

I emailed Steve and he wants $2300 for his headers and says he has 5hrs on the Apex motor. I still think the

RX1 and carbs are a better choice (for me)...I can work on carbs.

I worked many years as a millwright, and can build most anything...given enough time and money..:P

So, I plan to build the motor mt and exhaust...possibly air box. But, anything can change at any time...

I guess, what I am really doing... is rambling on... trying to keep this thread going...trying to inspire..

Love all your work...postings etc..   Just...  GIVE ME MORE...

I realize that I am 2 years out...from the initial hype. That's right...don't follow me in the stock market...John O

 

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Posted

Love to see see someone local within an hour or so flight tackle this install on an Avid. Hoping to get back to my A+ this year and   that is the only conversion I'm interested in at the moment. Would make a kick ass amphib!

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Posted

You're right...it would make an awesome amphib.

I am waiting on pulling the trigger, on a motor, until I 

hear back from Teal. I don't know if he has anymore adapters for the RX1. I have a C box on my 582.

Hoping to get started during the "mushy month"  coming soon...

 

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Been flying my Avid+ on skis with the RX1 engine and she launches out of a foot of snow like its ass is on fire ,lol. So far very happy with the conversion, We have about 3 feet of snow this year almost like the good old days ,I will try and get a video one of these days.

IMG_2341.JPG

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Posted

Whats the difference between the apex and rx1 engines?

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Posted

RX-1 four cylinder carburated, Apex three cylinder EFI.  That’s the way I understand it. 

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Posted (edited)

The 3 cyl is in the Vector, Nytro (120-130hp), and sidewinder (180-280hp factory turbo) sleds.

Rx1 is 4cyl 140hp carb and apex is 4 cyl 150/165 hp efi.   The 4 cyl motors have a built in rubber damper within the internal gear reduction (see pic) and are arguably beat suited for conversion because of that.  The 4cyl motors are sometimes turboed in the 210-280 hp range in sleds.

A great read on yamaha engine development:

https://global.yamaha-motor.com/business/4st-snowmobiles-10th-anniv/edition3/feature_001/

pic_001.jpg

Edited by Yamma-Fox
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Posted

I am still supplying the RX1 to C box adapter at this time. I think the Apex will be a good alternative in the future but there is somthing to be said about the simplisty of carbs. 

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Posted

Why do you guys always use the C gearbox? Why not the E box?

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Posted (edited)

The "E" box has the starter mounted to it, therefore is not compatible with the necessary clutch.  The Yamaha has it's own starter.

 

 

 

Edited by Av8r3400

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Posted

I...for one, am delighted :P     that  Teal is going to continue to make the adapter for the RX1. Many

others are on the verge of jumping into this conversion, and I think are more comfortable with carbs as well...

What better timing...Winter is winding down...Sled prices will be dropping...

Hope to have an  engine in hand soon..

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Posted

Why do you guys always use the C gearbox? Why not the E box?

Although it still remains to be done, in theory an E box would be a direct fit on teals  RX1 adapter.

The clutch would still work fine.  The reason the clutch is not listed for use in the ebox is that you couldn't start through the ebox starter (with a disengaged clutch).  But in the case of the RX-1 you wouldn't need to.

Obstacles include:  slightly more weight and bulk, would have to remove the starter, block off the hole for the starter, and fabricate a spacer where the starter shaft was.

Upside is that new e boxes are readily available from rotax.

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Posted (edited)

What is the clutch even used for for this engine? If its a starting issue cant you just find a starter with a bit more snot behind it. A clutch to me is just another point of failure. Think if it was me I would loose the weight of a clutch leave the Ebox starter and try to run it parallel with the engine starter, Maybe there is other factors as well?

Edited by TJay

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Steve Henry has been running the RK400 clutch without failure other than the first (?) one due to a bearing issue.  His new Apex engine is over 150 hp, plus Nitrous.

Running and synchronizing two starters is far more weight and complexity than the clutch, with the added possibility of bind and locking up or destroying the entire system.

The starter is not strong enough to swing a propeller fast enough.  This is designed to be a SNOWMOBILE engine, not an aircraft engine.  It's designed to turn a low inertia primary clutch on a sled.  Putting a stronger motor on the starter may not solve anything if the starter drive design can't handle the torque needs, either.

 

Yes, I am coming around on the idea of the Yamaha power system.  I'm not there yet, but I am watching and learning as much as I can.  For me it means a better supply of used 912 engines on the market, which is a good thing.

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Posted (edited)

I think teal said that the e-box will not fit on the RX 1 with the starter attached. The starter sticks too far back where the motor is.

 

The issue with starting without the clutch is more of a  low idle engine problem, and not a starter problem.   As I am told, with a big prop the starter spins it up fine, but the motor itself will not be able to fire off and accelerate to idle.  It can get into a "shake" unable to achieve full Idle.

Edited by Yamma-Fox
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Posted

At -20c my RX1 engine couldn't seem to spin over fast enough to fire  once it warmed up to -12 or so it started no problem, I only seem to get the shake problem restarting the engine after it has been warmed up, usually a quick shot on the throttle gets it past the low idle shake and it runs smooth but a clutch would diffenently help on the cold starts

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Posted (edited)

At -20c my RX1 engine couldn't seem to spin over fast enough to fire  once it warmed up to -12 or so it started no problem, I only seem to get the shake problem restarting the engine after it has been warmed up, usually a quick shot on the throttle gets it past the low idle shake and it runs smooth but a clutch would diffenently help on the cold starts

Good info Willis!   Thanks.   And keep an eye on that rubber hardy disk.   It holds up great for most everyone, but I hear it can possibly get stretched with use on bigger/heavier props.

Guess I've only heard of one instance,  so probably not a big worry, especially like teal says that the disc's fail mode is running but without dampening.

Just maybe something to keep an eye on during inspection, or maybe you could detect that with a prop free play check during preflights.

Edited by Yamma-Fox

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