Yamaha RX1 Engines

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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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Posted

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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Posted

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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Posted

So Im trying to get as much info as I can on these because I have always liked Yamaha engines. You guys say you get a shake at idle? Can you not just turn up the idle like every other gearbox driven aircraft engine?

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Posted (edited)

I haven't seen the "shake" myself, but am told it can be pretty rough.. 

I decided to skip that excitement / frustration and go with the TMR400 clutch from Twisted Metal Racing (Canada).  Tony there was a co-designer of the original RK400 and holds production rights.  After discussion here with Leni, and after talking with Tony, Teal, and Steve Henry I became convinced that the clutch was the way I wanted to go for a couple reasons:

1. Cold starts and uncoupled warm up with the big prop

2. Easier on everything during start and shutdown.  No shakes during startup, and the yamaha 4 strokes shut down fast and hard compared to 2 strokes that "coast down" smoother.  Both of those situations (especially the shakes) can be a little tough IMO on the rubber hardy disk, gearbox, engine mount, airframe, and any components mounted FWF.

3. The engine already has a rubber damper built into it (see pic and post above), so there is less need to have additional dampening.

4. Seaplane use of "Neutral" at idle

5. I can go up front and tell people I'm running a turboprop while freewheeling the prop by hand.  (The only reason really.... I made that other stuff up!) :lmao: 

Edited by Yamma-Fox
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Posted

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.

I just shit myself... :lmao:

 

:BC:

 

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Posted

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.

I just shit myself... :lmao:

 

:BC:

 

Makes a lot more sense than a Arctic Cat engine...

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Posted

I’m officially kicking myself for selling my RX-1.  :blink:

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Posted

I’m officially kicking myself for selling my RX-1.  :blink:

I really think you did the right thing!  

It looks great on the front of my plane.

:BC:

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Posted

Somehow I knew you were going to chime in. I'm glad you like it. 

 :lmao:

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Posted

the yamaha 4 strokes shut down fast and hard

That sounds an awful like your typical 912, someone needs to develop a YamaSoftStart module lol.

Seaplane friendly, yesss!

Bravo! By the time I'm ready to power up my A+ I figure you guys will have all the kinks worked out.

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Posted

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.

I just shit myself... :lmao:

 

:BC:

 

Makes a lot more sense than a Arctic Cat engine...

douche  I meant touché  damn auto correct.  :lmao:

:BC:

 

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