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

109 posts in this topic

Posted (edited)

TUBE COPING / FISHMOUTH TEMPLATES

Starting in on the mount.

You smart guys already know about this, but for anyone like myself who didn't know:

Go to the site below and enter your tube dia, thickness, the angle of the joint, and the mating tube dia.

You get a printable template that you can trace to make a perfect grind on the first try.  Way too cool!

http://www.metalgeek.com/static/cope.pcgi

(I happily threw this guy a few bucks donation to help keep the site going: https://www.dreamhost.com/donate.cgi?id=1797 )

(Oh yeah, and this guy too!  http://www.avidfoxflyers.com/index.php?/topic/2202-contributions-to-keep-site-going/ )

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Edited by MN Kitfox 2
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Posted

This is very cool. I've never used this before. I used to grind and fit and grind and fit etc. until bought a JD squared beast. Thanks for sharing your progress Brett, new and experienced builders will benefit from your build.

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Posted

I have used that printable template calculator for a variety of diameters and angles. As long as I feed it good information, it works EVERY time. Especially cool when dealing with two tubes of different diameters. Bookmark the link and remember you have it saved!

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Posted (edited)

I'm a moron, but I was able to hit my very first fitup nuts on with the first grind!

Trick #2  is to make templates for both ends of the tube, wrap them on the tube and tape them up so they will still slip off.  

Next sleeve the two paper tubes together and fit them up on your work (paper tube only, see pic).  Spin and slide them till they line up and contact perfectly, then tape the two halves of the paper tube together at that alignment and slide them on the raw tube.  

Mark the tube with a sharpie and grind both ends perfectly in one shot.

For longer sections of tube, I made my paper tube template with an extra section of rolled paper between the cope templates.

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Edited by MN Kitfox 2
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Posted

That's a good method.  I was aware of the template generator, but didn't figure out the best way to handle the two ends.

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Posted (edited)

Thanks everyone for tuning in here and watching over my work.  I really do appreciate it and welcome the experienced oversight!

Most of my info is well known to the old pros on this site I'm sure, but hopefully I can contribute a little here and there sometimes to pay ya'll back for watching over the rookie.

And hopefully this "ordinary guy" build thread will inspire others that: "if THAT guy can do it.... I could do it!"   LOL 

Here is a video I made of coping the tube:

 

Edited by Yamma-Fox
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Posted (edited)

OK.  The basic frame of the mount is all done and ready for the pro welder.  It'll come back built enough to hang the motor and figure in addnl stucture and accessory mount points before it goes back for final welding and powder coat.

Also note that in building my mount using the firewall as my jig (and not a proper jig), I used oversize tube (3/4") at the FW mount points and am using brass bushings with an offset hole (not in middle of bushing) to allow for the  small amount of warp that I anticipated the mount would undergo in welding.  So far that plan has worked well and I only had about a third of an inch warp in the main weld-up of the mount.

Next will be some slow going while planning out and ordering all the little hardware and connections for oil and  cooling systems.

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Edited by Yamma-Fox
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Posted (edited)

OIL LEVEL LOW WARNING LIGHT 

I checked the oil dipstick in the yamaha oil tank.  It has a float switch integrated in the dipstick that senses oil level.  The two electrical leads to the dipstick have continuity when the oil is low, and are open when oil is adequate.  Looks like it would be simple to wire up a panel indicator light for low oil.

https://m.ebay.com/itm/ATI-22mm-12V-DC-Red-LED-Flashing-Buzzer-Pilot-Panel-Indicator-Light/221805674839?_trkparms=aid%3D111001%26algo%3DREC.SEED%26ao%3D1%26asc%3D20160727114228%26meid%3D3c2c8a55e64c42819050cf45a128bd70%26pid%3D100290%26rk%3D1%26rkt%3D4%26sd%3D221805674839&_trksid=p2060778.c100290.m3507

Edited by MN Kitfox 2
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Posted

Nice job. What kind of door latch is that? How about a picture of lower mount area.

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Posted (edited)

Nice job. What kind of door latch is that? How about a picture of lower mount area.

New plane for me, not real nuts about the door latch.  Works great, but it is a little tough to get to and open from the cockpit  in a hurry (egress).  On the to-do list to modify.

 

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Edited by MN Kitfox 2
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Posted

Before you paint, I would suggest taking with Leni directly about making a Jig off that mount.  You may be able to sell the jig to him so he can go production...

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Posted (edited)

Before you paint, I would suggest taking with Leni directly about making a Jig off that mount.  You may be able to sell the jig to him so he can go production...

That's a nice compliment to my first attempt at a motor mount.  Thanks!

But like with Leni's new bush gear design, I would want to test this out a bit, prove it out, and look for possible improvements before considering having other people copy it.

There are a lot of KF 5-7s out there, and I think the 4 uses a very similar mount.  I've also heard that the RX-1 and Apex use the same mount, so it is possible there may be some interest in it I guess.

 

 

Edited by MN Kitfox 2
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Posted

Wow! very nice.  Do you have someone to weld it up for you?  There is a guy in Hibbing that does tig welding on airplanes.  He is the welding instructor at the Eveleth tech school.  He has done stuff for me in the past and is going to weld up the improvements on my Kitfox 4 rebuild.  JImChuk

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Posted (edited)

RX 1 ENGINE OVERVIEW AND PROJECT PROGRESS:

 

In my video (above) you see Teal's Skytrax adapter mounted with a Rotax C box.  Truly the work of a craftsman!   This 2nd video is Teal with the install instructions for the adapter, C box, and clutch / hardy disk.

Edited by MN Kitfox 2
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Posted

Very nice  video.  Very informative as well.  JImChuk

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Posted

I would triangulate your mount where the upper and side mounts connect to the runners. see picture.

bret.mount2.png

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Posted (edited)

 

Good idea.  Thanks for checking it over!

Yes and as I was talking with a buddy here today, I think I will get it back from the welder, mount up the motor and fit all the accessories  (airbox, oil tank, coolant system, ect).  Then I'll mark off where I can add in some extra tube.  In studying other examples it looks like I should be doing exactly what you suggest, essentially running two braces from every firewall mount location, making a triangle of support from each.

 

Edited by Yamma-Fox
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Posted

I wonder what the fwf will weigh?

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Posted (edited)

I'm not sure what it'll weigh in at....  As I remember, some installs come in around 170-180 with everything.  Mine will be more than that though with a heavier mount and accessories.  I hope it weighs in  25 to 35 lbs less than the subaru did (NSI paperwork puts the fwf subaru at 225lb).  Will report numbers down the road when all my stuff is in there.

Edited by MN Kitfox 2

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Posted

I'll be following this thread as I'm sincerely interested in this conversion. I have Subaru now and so far so good. But would really like to shed some weight. Very informative thread thank you. 

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Posted (edited)

I'll be following this thread as I'm sincerely interested in this conversion. I have Subaru now and so far so good. But would really like to shed some weight. Very informative thread thank you. 

My biggest worry about this engine is the 10,000 rpms, compared to 5000 rpms for the Subaru which has run 300-400,000 miles in a car without rebuilding.  How many miles does it last in a SnoGo?  EDMO

Edited by EDMO

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Posted

I'll be following this thread as I'm sincerely interested in this conversion. I have Subaru now and so far so good. But would really like to shed some weight. Very informative thread thank you. 

My biggest worry about this engine is the 10,000 rpms, compared to 5000 rpms for the Subaru which has run 300-400,000 miles in a car without rebuilding.  How many miles does it last in a SnoGo?  EDMO

I agree, that's my concern but really, my only concern is the high Rpms to achieve the hp. I'm just really trying to find a way to achieve more useful load without going back to 2 stroke. 

My plane is totalling 722lbs and with two of us flying there's limited space left for fuel. 

I have completely rebuilt a BMW 1150 engine but am just at a wiring harness and computer snag. Until this Yamaha engine caught my eye

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Posted (edited)

I had the same thoughts guys, and have had 16 subaru cars in the family with millions of low maintenance miles on them.  But here's what I came to:  

Subaru car runs avg 2800 rpm and what maybe 60ish hp avg cruising along at highway speeds.  The Subaru in airplane works much harder for sure, and is typically modded up for more hp, which I find troubling.

The yamaha on the other hand runs 10,300 rpm in a snowmobile and the R1 motorcycle that the engine was born from raps out 15,000!  Stock HP is 140, but sled guys run turbos in the 200+ HP range with very reliable results.  It therefore, conversely to the subaru, is running detuned in the airplane (which I find comforting) at about 9200 rpm and is internally geared at 1.19 to an output shaft rpm of 7700 and 125-130 hp.

The snowmobile guys have reported it very reliable with many machines over 30,000 miles (approx 1000 hrs at an avg speed about 30-35 mph) and mote than one example with over 100,000 miles.  That can be contrasted to the generally accepted rebuild time for a 2 stroke snowmobile in the 6,000-9,000 mile timeframe.

Is the RX-1 perfect in the snowmobile? NO.  Do they break down or fail in the snowmobile?  Rarely, but yes.  But so would some Subarus that were modded up for more hp by shaving heads and changing cams (as I understand my 118hp NSI e-81 was).  Especially if that modded subaru car was pushed for near max hp for 10 min straight like it often is during takeoff and climb in an airplane.  Yes, sooby lovers, they do do well in airplanes, but they are not perfect either! 

So along those lines of thought I found more comfort in the Yamaha over a Subaru (detune vs. "uptune").  The big question then was how about yamaha over rotax (912/914).

To that I entirely concede that a 80 or 100 hp rotax has an outstanding reliability factor, with decades of data to back it up.  Problem for me is that I want to run a continuous 100 hp, with 130 available to get off the water and over the hill on the other side of the lake.  Rotax wouldn't do that unless I did a zipper type kit.  But a zipper kit strips the top half off that ultra reliable rotax and replaces it with aftermarket parts... and again we are trying to get MORE out of an engine than it was designed for, instead of detuning from it's design.  That (zipper) was going in the wrong direction for my taste, and also way out of budget.

So then along comes Steve Henry.  The first big name to run the RX-1 in a fixed wing plane, tune it correctly, push it hard, and prove it out.  Teal's kit had been out for a few years (run mostly in gyros) and the motor and c gearbox proved to hold up well, then Steve proved it for us airplane guys and worked out some important details along the way.  

With steves plane (now sold) at over 700 hours, a couple of other yamahas in that 500-900 hour range,  and 20 or 30 other skytrax conversions along with approcimately 100 other Yamahas out flying, so far we have no reports of engine failures and only two reported significant malfunctions, both in the rotax c gearbox due to improper assembly on one and the pinion shaft bolt coming loose on the other.  In both cases, the gearboxes held up for some time before the problem was noticed and the pilot did not suffer power loss.

So the track record in the air has been very very good so far.

Anyhoo,  with that background on Teal's Skytrax kit, along with my experience with my RX-1 snowmobile, I decided to move ahead with this project.  And as with any single example of a particular plane and engine, only time (and some luck) will tell if I made a good choice ;)

 

.

Edited by Yamma-Fox
Update sept 2018
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Posted

I cant argue with your logic on the SnoGo engine.  It has been too many years for me to keep up with the original article I had about the testing Subaru did on their engines, but in a nutshell:   Aircraft engines are "certified" when they are run on a test bed, some of the time at idle and or part-throttle for 150 hours - maybe not continuous.  Subaru put 6 or 7 of its cars on a track and ran them day and night continuously at WOT for about a week, stopping only long enough for fuel and changing drivers - I think they ran about either 60K or 100K during that time.  I believe someone calculated that they had to be turning over 6000 rpm to do that mileage.  All of the cars finished the test run without one repair or failure.  That's endurance!  EDMO

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Posted

Yep, those subarus are something!  The only one of the 16 I blew the motor on was an old undermaintained 1978 1600cc.  It was my fault and not the cars ;)

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