YAMAHA RX-1 (140 HP) install in Kitfox 5

[dholly 718]

I know this probably won't be a popular comment but there looks to be more than enough room to add a nosegear weldment to the Yammy mount. Given the popularity of the KF6-7 'convertibles', it might be something to consider for future sale benefit. Kinda like adding float brackets to your fuse even though you don't have current plans to fly off water. Your own mission might even change down the road, who knows? 

[Yamma-Fox 403]

Ready to hook up hoses and fill fluids!  More pics tomorrow, but here is the oil hose and clamps I chose.  This hose size fit perfectly for the 3 main runs and is far more Heavy Duty than the hose used on the snowmobile.  

The otieker clamps are said to be far superior in positive clamping and not loosing tension through heat cycles.  The kit below includes sizes that will also fit my 5/16 fuel hose.

Edited 1 Nov 2018 by Yamma-Fox

[Yamma-Fox 403]

FUEL SYSTEM:

Hooking up my fuel feed today.

I went with a Facet 40288 (2 - 4.5 psi) with a built in check valve that allows free flow through it but no backflow.  

Past the Facet pump I put one of the Yamaha vacuum pulse pumps in a parallel loop as a backup in case the elect pump fails.  (Note that the pulse pump does not allow flow through it in either direction, so it needs a bypass line around it in case it fails).  

In the pic below I forgot to label a check valve I'll be putting in the bypass line between the facet and the fuel pressure guage fitting.  It will go in the location of the green circle in the pic below.  Without it, when the pulse pump is running standalone it would "feed itself" in a loop (instead of the carbs) and will not draw from the tank.

Of course all this will be firesleeved / heat shielded as well due to proximity to exhaust.

I will test to confirm how this all works and update this post.

Edited 1 Nov 2018 by Yamma-Fox

[Yamma-Fox 403]

Pretty boring video here!   

It's a systems lookover prior to ground testing:

[wypaul 448]

Wow, coming along nicely can't wait for the test runs. 

[sky4play 55]

Lookin good....Y-Fox.

Now I feel way behind. Really like all of your electrical ideas. Will probably hit you up on that...since I am an electrical idiot.

[marshawk 82]

Looks great, a lot of good ideas that you are adding to your build ,looks like you will be testing it on some skis very soon

[Yamma-Fox 403]

After all these boring "technical" posts, here's a practical one!

[sky4play 55]

Way to go...... The sweet sound of  success. Nice job. I am sooo  jealous right now...

[Yamma-Fox 403]

Here is a video of me testing ignition sources and fuel delivery:

https://youtu.be/wLrP70CLfi8

And below are tools that make life a zillion times better when doing carb work.  The long hex wrench reaches way in to get to the inner airbox screws and the upgraded carb float bowl screws, the jets are available in many sizes and come in pairs... so only order 2:

 

[ebostrom 1]

Could you tell me how you figured the thrust angle for the Yamaha RX-1 engine in your kitfox.

Edited 10 Jan 2019 by ebostrom

[Yamma-Fox 403]

I just talked to a few people and came up with a couple degrees left and "zero" up/down.  Nothing really scientific, might shim the mount a bit if I find I want something different. 

The skytrax apex (with it's 3 gear gearbox) turns a right hand prop as opposed to my left hand RX-1 so it could possibly benefit from a couple degrees right.  The angle is to counter the P factor.

UPDATE AFTER FLYING:

The plane is flying really well and I'm happy with the angle I put in.  If anything I do notice that I find I need a little left rudder trim now in cruise and there is a bit of "power up - nose up".  So I don't know if a little down angle would have reduced that tendency or not?

 

Edited 6 Apr 2020 by Yamma-Fox

[ebostrom 1]

Thanks for the info. My engine should be here on Thursday and will be starting on building a test stand. After the test stand I will be making a engine mount. Can't wait to get started. Thanks for all of the info you have shared with all of us. Eric 

[akflyer 1427]

you guys are really making me think about putting one of these on my coyote.  They were originally designed for a 100 hp honda engine conversion.  putting 140 - 150 in the nose on the cheap sounds better to me than going with the 0290 that was originally put in the coyote I have.  I have to build an engine mount for it either way I go so the availability of parts etc is now making me lean towards the yamadog.  Now to start saving pennies for the gear box!

 

[TJay 1041]

you guys are really making me think about putting one of these on my coyote. 

 

Amen to that one

I'm strongly considering one for my next project too.

[nlappos 413]

you guys are really making me think about putting one of these on my coyote. 

 

Amen to that one

I'm strongly considering one for my next project too.

Me too! Next year.

[Av8r3400 1177]

Wow.

[ebostrom 1]

Do you know of anyone who is flying a kitfox model 4 with a Apex engine. Thanks.Eric

[Yamma-Fox 403]

Do you know of anyone who is flying a kitfox model 4 with a Apex engine. Thanks.Eric

A lot of Apexes are mid-conversion at this time but only a small number flying.  By years end that will change big time there are a few RX-1 powered KF4s out flying.

Edited 27 May 2019 by Yamma-Fox

[ebostrom 1]

Thanks. Just don't know how it will fly with the extra weight and if it will hamper flying with two people weight wise. Just thinking I should get a 5 or 7 and get rid of my 4. Do you know of anybody getting rid of a 5-7 unfinished or even damaged would be fine. Thanks. Eric  

[1avidflyer 1983]

A Kitfox 5 just came up for sale on the Team Kitfox site.  It's a complete airplane with an O-235 in it.  New York state.  JImChuk

[ebostrom 1]

Thanks. Will look at it. Eric

[Yamma-Fox 403]

Spring update on the project:

Couple videos of where I'm at and how much i love how this engine doesn't "drip a drop"!

[MnAvidFlyer 34]

Subscriber...thanks for taking the time to produce the vids. I would like that same setup one day.

Brooks

[skypics 89]

What is the weight of the Yamahopper?

John M