YAMAHA Genesis (RX-1) install in Kitfox 5

58 posts in this topic

Posted (edited)

Ok guys.  Looking for help and input here!  

This will be a big project for me and I'd like to lay out my plan of attack for ya'll to review as I go.  It's a such great group here and I will be thankful and greatful for everyone's help.... please don't hold back if you have an idea or advice!!

I also hope that this build thread will provide good info for anyone interested in the Yamaha power option.  Hopefully people can learn a little from both my successes and from my mistakes. :)

First a little about me so you know what you're up against!

Not an EAB builder.  Reasonably decent mechanic, but not an experienced fabricator.  Aero Mfg. Engineering B.S. degree which helps a little, but mostly put emphasis on the "B.S." since I never actually worked as an engineer. Also keep in mind that I am interested in a functional and safely done repower and install here...   but this is NOT going to be a "show plane", so looks, beauty, and a perfectly "clean" install are low on the priority list.

So I got my bird crammed into my garage yesterday, pulled the prop of the subaru and am getting ready to dig in.   Here's my initial game plan:

1. Take lots of pics of the sooby and measure up location of prop flange to hopefully eliminate too much cowl rework in the end.

2. Pull the motor and take a look at the soob motor mount.  I was considering building off it if possible to simplify the fabrication process.  Any concerns with that?

3. Get things lined up, plan for airbox and exhaust, then tack together the new mount.  I am a novice welder and own only a cheapo wire feed welder.  I'd plan to emulate what others have already done and fishmouth the thing together and just tack it, then send it off to a pro to TIG it up and powdercoat.  (I'd be glad to hire out the entire mount fabrication but so far I'm the first guy I know of to put a Yamaha in a Kitfox, so it would presumably be hard for someone else to build me a mount without a KF5 firewall jig and a RX-1 motor laying around)  Any ideas / thoughts? 

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Edited by MN Kitfox 2

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Posted (edited)

There are lots of posts in the 4-stroke section about the Yamma engine and I believe there may be photos of a mount - I don't know if it is for Avid or Kitfox.  Guess you have looked at them?  Maybe you should post your progress there?  Your NSI might be worth a little more if the mount was included.   Firewall jig is easy - clamp a piece of plywood and outline to your firewall and drill thru the mounting holes - weld up frame using that - Well, your firewall isn't flat, so you may have to build something to fit.  I went the opposite way - Had Pelican mount for my Soob and used it to add mounting bushings to firewall.  You could probably do the same with an Avid mount.  EDMO

Edited by EDMO

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Posted

There is probably a few different ways to build the motor mount ,we ended up bringing the tail up to level the plane and had a bench on wheels the exact high we needed to sit the RX1 on. When we had all the right angle and measurements from the firewall we installed the larger  main  mount to the motor and then tacked on each of the smaller pieces from the firewall to the main mount, There wasn't much room left from the back of the RX1 to the firewall on my avid but your kitfox may have more room depending on your cowling,

Good luck on it

 

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Posted (edited)

Thanks guys.  I like the rolling table idea.  That'll make life alot easier!

Edited by MN Kitfox 2

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Posted

Everyone needs a gantry at there hanger for times like this . It made pulling my motor way easier . 

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Posted

I don't have a gantry, but a fold-up 2000 lb hoist from Harbor Freight for about $179 made it easy to lift and move my Soob engine.  EDMO

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Posted

We've had this thing for about 15 years from harbor freight my dad had a couple raf 2000 gyros we built and used this for the hang tests. I've thought about getting rid of it but always end up using it . It just rolls to the back out of the way. Several people around the airport have used it for various projects and a couple gyro hang tests for people too . I definitely don't plan on trying to sell it anymore as it will always come in handy. 

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Posted (edited)

The easy part.

(Decided that the soob mount wasn't even close to what I'd need for the yammy)

Pic 2 shows tailwheel spring support.  With the motor off she'll be a wee bit tail heavy!

Pic 3 is my quick little (sorry ass) attempt for a prop flange locator jig. (Bolted to firewall)

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Edited by MN Kitfox 2

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Posted

Harbor Freight has two tables like this that jack up[ 500 to 1000 lbs about 3 feet, might that help mount that engine?

harbor freight.jpg

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Posted

What are you going to do for a wiring loom? I want to do the same conversion.

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Posted

My hanger neighbor used all the wiring and everything that was stock with the motor. He put one in his own design gyrocopter. He's working out some non motor related kinks but is getting 90mph cruise conservatively. 

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Posted

Not trying to be offensive but........... The thought of doing 90 plus in that thing would empty my bowels into my britches! Pretty cool that he can design/build/fly it, though. Hat's off to him!!!

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Posted

What are you going to do for a wiring loom? I want to do the same conversion.

Mine is a carbureted (RX)-1 4cyl.  Teal Jenkins  (skytrax) sells the c box adapter and wire loom (which is very simple for that motor).   I believe he is working on an  adaptation for the EFI 4 cyl (Apex) as well, which requires a MUCH more complicated wire loom mod.

More info on the RX-1:

http://www.avidfoxflyers.com/index.php?/topic/4138-yamaha-rx1-engines/

 

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Posted

Harbor Freight has two tables like this that jack up[ 500 to 1000 lbs about 3 feet, might that help mount that engine?

harbor freight.jpg

I have one of the 500lb, and one of the 1000lb, they are the handiest things I ever bought.  If you need higher lift, Northern Tool has some that lift more than 2x these.  I haven't found a need for them yet, but I bought a forklift, so my lifting needs are pretty much taken care of.

Mark

 

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Posted

I've been around gyrocopters half my life so it's normal for me . But yeah I can tell you the first time I flew in one I was sucking the seat in my cheeks. After building a couple with my dad and working for a company building them I still get amazed by what you can do with one . That is one loud engine though , he did a couple fly bys and I was going to film but forgot . It seems like it'll work great in a avid or kitfox. I'm seriously considering it when it's time to replace my 582. 

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Posted

Roughly lined up. .. 

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Posted

I looked into the wire loom in detail.  

Teal has full (one page!) instructions and has made it super simple:

From Teals harness:  Hook up batt positive, ground engine to airframe (my airframe is common ground, I'll run a heavy wire to it from the starter mounting bolt on motor.  Hook up the ignition supply wire (I'm going to two switches for redundancy, one to hot batt, one to engine alternator/magneto).  Hook up starter solenoid wire to the start button in plane.

That's it!  Teal also has one wire ready for the tach and the rest are plug and play connectors to the small weatherproof ECU and VR boxes, and also to the spark plug caps (with built in ign coil on each)

I will add a fused switch to the electric carb heaters installed in the carbs on the yammy. This bird will fly all winter here in N Minnesota and the elect carb heat helps supplement the standard carb heat (heated by engine coolant) 

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Posted (edited)

the easiest way I came up with for the mount fab.  Make a jig that the mount bolts to, and that the prop flange bolts to all in one.  Unbolt the old engine and bolt the new engine to either the firewall of the prop flange and block the engine up.  Figure out how to fill in the blanks.  This will put the prop in the right spot on the cowling versus firewall for minimal if any cowling modifications. 

 

Look up the thread I did on the 912 mount.

 

Gives you an idea of what I am talking about.  I started with a 582 mount that gave me the firewall pattern.  Then I bolted the 582 and gear box to it so I could locate the exact prop location.  Pull the 582 and the mount and start filling in the blanks.  The first jig sucks.  The one you make to locate everything wont let you weld it out without having parts move around as you weld them so I ended up with 2 jigs.  One to tack everything in place and one to bolt all the hard points into to keep it immobile when welding.  After I welded it out I did a semi stress relief by heating up all the weld areas and heat effected zones and then wrapping it in insulation and let it slowly cool.  The result was a mount that did not wiggle when the bolts were pulled out of the jig.

 

:BC:

 

 

Edited by akflyer
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Posted

Hi I was wondering if I could bother you for a couple of measurements before I go look at this sled for sale.Prop flange to fire wall I have 24in. The problem I see is I have a lower step of 4in down 12in from the.top of my cowling. Thanks.

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Posted

Hi I was wondering if I could bother you for a couple of measurements before I go look at this sled for sale.Prop flange to fire wall I have 24in. The problem I see is I have a lower step of 4in down 12in from the.top of my cowling. Thanks.

No problem.  I'll send you a PM here when I get home and we can figure out how it'd fit.

Brett

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Posted (edited)

OK.  So a member here whom I highly respect brought up a challenge to a premise I had made when choosing the RX-1 motor for repower.  I am glad he did because it helped me come up with a plan to test my guesstimate.

My premise was that if an RX-1 lost a cylinder for some reason (bad coil, spark plug, burnt valve, flake of gunk plugging a main jet.... whatever) that it would still pump out about 70-80 hp running on the remaining 3 cylinders.  Note here that the RX-1 uses four fully independent "CDI/coils" integrated into each of the spark plug caps, so in a very loose sense it does offer some redundancy in the ignition system. 

Based on my experience with my 65 hp KF2 on lotus floats, I figure that 70-80 HP would be enough to eek out a meager climb (150fpm) in my heavier KF5 on lotus floats.

So tonight as I was sitting in my bow stand (waiting for deer that never came by) I realized that I had in my snowmobile arsenal both a strong running RX-1 and a strong running Ski Doo MX with a Type 467 Rotax (little brother to the 582 and 532).

The 467 in a snowmo puts out about 70 HP, which is about the minumum where I hope the 140 HP RX-1 will run on 3 cyl.  So this winter I will get both sleds out on the lake and pull a coil lead on the RX-1.  Line em up in identical conditions and see how they match up in a race.  If the RX-1 is pumping about 70 hp, then the much lighter Ski Doo should pull slightly ahead in a race.  I'm hoping that the RX-1 will hold its own and be neck and neck putting it's hp in the mid or upper 70's.

So for anyone who cares (probably only a very few that are considering Yamaha power), I'll post up the results.

 

Edited by MN Kitfox 2
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Posted

Unless you adjust the RX1 clutching to make up for the 25% power loss this won't be much of an accurate test.

 

 

Ken.........

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Posted (edited)

Unless you adjust the RX1 clutching to make up for the 25% power loss this won't be much of an accurate test.

 

 

Ken.........

You're 100% right.

It'll be under revving and running lower in the power curve.  Capable of more HP if I reclutched for more rpm.

Hadn't thought of that.

But, thinking a bit farther, the same could be said for a fixed pitch prop on a plane where you suddenly dropped a cyl.  So in that sense it would be an accurate test, or at least accurately representative of the performance loss you might enconter.

Agree?

Edited by MN Kitfox 2
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Posted

yes I agree.  Your not going to stop and re-clutch / gear in the air.  Dont over think this one :lol:  Dropping a cylinder on the trail and dropping one in the air will be close to same as the clutching and the gearing / prop pitch will be pretty much the same load on the engine so I would say its going to give you a rough idea of what to expect.

 

:BC:

 

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Posted

Unless you adjust the RX1 clutching to make up for the 25% power loss this won't be much of an accurate test.

 

 

Ken.........

You're 100% right.

It'll be under revving and running lower in the power curve.  Capable of more HP if I reclutched for more rpm.

Hadn't thought of that.

But, thinking a bit farther, the same could be said for a fixed pitch prop on a plane where you suddenly dropped a cyl.  So in that sense it would be an accurate test, or at least accurately representative of the performance loss you might enconter.

Agree?

You have me confused on the "clutching / reclutching" - Can you explain more about that?  I thought your clutch would only be disengaging  when engine power was completely shut down?   Are you talking about changing the prop pitch - IFA?  EDMO 

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