New Approach to Yamaha RX-1 conversion

[teal]

This is not my install. It is a friends trike install

 

[Rambler]

A few point of views of the RX-1 I have set to use in my gyro build.

Many Thankx to Teal Jenkins for the awesome adapter.

It could not have been an easier install and precise fit. Genius. Worth every penny!!:usa2:

I will post more later in another thread once the Wolverine is finished and test flown.

 

[scottessex]

WOLVERINES!


Nice very nice!

 

[Kevin_Richey]

Cool and a half!

I'm actually jealous of the horse power the four cylinder Yamaha produces, & I fly the 3 cylinder one!

But, I don't even use all the 120 horses available...

 

[Trackwelder]

Laying yamaha on side

Laying yamaha on side

I know that with the pusher configuration, you do not need any more prop height. I was wondering in order to make the engie useable for a tractor aircraft if anybody has looked into laying the yamaha on its side. I kow this has been done with other engines, but what would it take for the 4 cylinder?

 

[NoWingsAttached]

A complete fabrication of the oil sump and pickup tubes.

BTW: There is no reason you can't use the YG4 (or YG3) in a tractor, the only thing is that the prop diameter will be smaller with a conventional gearbox - hence the reason for developing the Hy-Vo chain Silent Drive. But the package has so much guts and so much less weight than a 912/914 that it really doesn't make all that much difference to use a gearbox in the interim while I continue flying off time on the prototype Silent Drive and testing gear wear and chain stretch. The tractor STOLs with YG4 power and a two-shaft gearbox far outstrip anything else in their class at competitions.

 

[NoWingsAttached]

My next YG4 project engine just arrived. This one is going to be using the Air Trikes SPG4 redrive which has been used on the larger Subarus in the past. I haven't received the clutch yet, I'm told it is used with the big BMWs that this PSRU is also popular with.

At $1800 for the 3.01:1 Air Trikes' PSRU, plus $490 for the clutch, the pricing is comparable to the Rotax "C" box.

 

[NoWingsAttached]

Cool and a half!

I'm actually jealous of the horse power the four cyliinder Yamaha produces, & I fly the 3 cylinder one!

But, I don't even use all the 120 horses available...

You have a really good exhaust on yours, so your mid-range power is not compromised. You don't need to go to WOT, because your exhaust was done right in the first place.

The other big mistake I continue to see being made is the intake. You will lose - and I personally guarantee this - at least 4 hp across the entire RPM range if you eliminate/replace the silencer with anything else known to date.

 

[Kevin_Richey]

You have a really good exhaust on yours, so your mid-range power is not compromised. You don't need to go to WOT, because your exhaust was done right in the first place.

The other big mistake I continue to see being made is the intake. You will lose - and I personally guarantee this - at least 4 hp across the entire RPM range if you eliminate/replace the silencer with anything else known to date.

Greg: Did you take a gander at the exhaust on my machine when it was @ Mentone last summer?

I have been considering changing it back to the stock Yamaha intake system to see if there'd be any changes in performance. Tried the Millenium/Yamaha engine helicopter plenum last June with disappointing results. Went back to individual air filters on each carb.

 

[teal]

3rd generation SKYTRAX

3rd generation SKYTRAX

This is the newest Skytrax.

 

[NoWingsAttached]

Greg: Did you take a gander at the exhaust on my machine when it was @ Mentone last summer?

I have been considering changing it back to the stock Yamaha intake system to see if there'd be any changes in performance. Tried the Millenium/Yamaha engine helicopter plenum last June with disappointing results. Went back to individual air filters on each carb.

I did check out your gyro at Mentone last summer.

I can guarantee you will realize a 4-5 HP gain across the entire RPM curve if you go back to the stock intake silencer, since this has already been proven with dyno tests done by the sanctioned shop that tests all the stock sleds for manufacturer's shoot-outs.

Those bare K&N air filters just don't cut it on a YG3/YG4.

 

[dinoa]

A complete fabrication of the oil sump and pickup tubes.

BTW: There is no reason you can't use the YG4 (or YG3) in a tractor, the only thing is that the prop diameter will be smaller with a conventional gearbox - hence the reason for developing the Hy-Vo chain Silent Drive. But the package has so much guts and so much less weight than a 912/914 that it really doesn't make all that much difference to use a gearbox in the interim while I continue flying off time on the prototype Silent Drive and testing gear wear and chain stretch. The tractor STOLs with YG4 power and a two-shaft gearbox far outstrip anything else in their class at competitions.

Do you have a breakdown of the Yamaha weights? What would be the installed weight difference compared to a 912?

 

[NoWingsAttached]

912ULS @ 100HP was reported by others to me as 175 installed. But it is not in the same class for power, so you have to go to the 914 for a proper comparison, which is 120HP and 195 lbs.

YG3 is somewhere around 120 pounds, YG4i is around 120, and YG4 is 125. I just did a gyro YG4 conversion for a customer and with the dual exhaust and mufflers l set up for him it weighed in at 170lbs with radiator, oil tank, all electrical parts, etc - everything except the battery to start and run the engine.

If you were to use the stock SS Yamaha sled muffler add 15 more pounds.

 

[Vance]

A divergent opinion.

A divergent opinion.

912ULS @ 100HP was reported by others to me as 175 installed. But it is not in the same class for power, so you have to go to the 914 for a proper comparison, which is 120HP and 195 lbs.

YG3 is somewhere around 120 pounds, YG4i is around 120, and YG4 is 125. I just did a gyro YG4 conversion for a customer and with the dual exhaust and mufflers l set up for him it weighed in at 170lbs with radiator, oil tank, all electrical parts, etc - everything except the battery to start and run the engine.

If you were to use the stock SS Yamaha sled muffler add 15 more pounds.

California Power systems lists the installed weight of a 914 UL with 115 horsepower at 161.7 pounds and.

California Power systems lists the installed weight of a 912 ULS with 100 horsepower at 148.2 pounds.

 

[dinoa]

Some weights http://www.rotaxservice.com/rotax_engines/rotax_914ULs.htm

 

[NoWingsAttached]

That's a big difference from the Viking Honda conversion site, their engine comparison figures I quoted. Thanks for the help in finding more accurate numbers for Rotax. I don't mind being corrected at any time, since I am not incorrect intentionally at any time.

So at around 120 pounds you can have
Rotax 912UL 81 HP
Rotax 912ULS 100 HP
Yamaha YG3 120 HP
YG3i 130 HP
YG4 142 HP
YG4i 150 HP

Add another 21 lbs and you can get a Rotax 914 100 HP, 115 HP for a few minutes.

Add the ancillaries to all of these engines and things shape up fairly equally in installed weights, while there is still no comparison in power.

 

[gyrodeputy]

Kermit took flight

Kermit took flight

I was able to take MY first 2 flights in Kermit last week at Rotors Over the Rockies.

The YG4 Conversion and the Skytrax (Teal) adapter are amazing.

So much power and performance.

I plan to tweek a couple items in the near future but otherwise what an incredible power plant and design.

Thank you to Teal for the support and great design.

There is a more detailed thread where I posted the details of the flights.

http://www.rotaryforum.com/forum/showthread.php?t=45643

 

[Jacko]

Pardon my ignorance; I just bought a RX1 sled and am taking out the engine. You guys are talking about a YG3 and YG4. Am I missing something? Are these different than my RX1 engine (inline Jap 4 cyl w/ carb)?

 

[Barney Bahle]

RX1 sled has a Yamaha Genesis 4 cylinder engine (YG4). Different names, same engine. The fuel injected version is found in the Apex sled, 06 and up. The YG3 is the 3 cylinder version found in the Nytro sled and possibly the Phazer??? I'm not so sure on those.

 

[NoWingsAttached]

Since interest is picking up regarding the use of the more complicated FI engines, I have started using the terms YG4 NA (normally aspirated, or carbs) and YG4 FI, as well as YG3 NA and YG3 FI.