Yamaha Genesis 120hp engine

OK Guys, I have thrust #'s for you...
It was a great day and my gyro seems to be pretty much in flying condition so I thought I would set the new prop up as well as do a thrust test. My engine makes its peak horsepower at 8,500 to 8,700 RPM's with a red line of 10,000. With 8.5 degrees pitch on the prop it holds my engine down to 8,000 RPM while pulling 450 pounds of thrust. I am leaning on the side of Conservative because I know I will get more RPM while at flying speed and get closer to the peak horsepower of 8,500 RPM at full throttle, If I need to flatten the prop out in the future to get the full RPM range I can.
I am very happy to be able to finally give you some Thrust #'s. This was done at about 60 degrees and at 6,200 ft above sea level. I have no idea what the results would be at sea level, I would assume even more because the thicker air would help both the engine and the prop. Anyways, I am very happy with the results of my thrust test today.

Attached are pictures of the progressive scale readings.
 

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Very cool! I still think that you will get lots better cruise with more pitch to slow the engine down some so the prop tips don't go supersonic. (make noise reduces thrust)

What gear ratio do you have?

Very impressive none the less, especially for your altitude.
 
3to1 gear reduction, 68" prop
We did go down to 7 degrees and it let the engine get to 8,200 RPM but I have no idea what the thrust was, It maxed out the scale.
 
Density Altitude

Density Altitude

At Colorado Springs Municipal Airport (KCOS reported conditions for April 12, 2008), Density Altitude at 1:54 PM was 6,779 feet.

With 60 degree temps and similar conditions, density altitude could easily be 7,000 + feet.

When you come down to Texas, bring your scale PLUS extra cable and a pulley.

RULE OF THUMB: Each additional 1000 ft of Density Altitude results into about 3.5% loss in horsepower.
 

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Yes Brent, I agree, I was not sure what ratio He was using, Too bad it is so dang hard to find a snowmobile down here in the south!
 
Todd I've been out of the loop lately with work getting busy. Today is the first day in a few weeks that I've been able to sit down at the computer and see what going on. You have totally outdone yourself And I look forward on hearing how it flys with your new prop. Best to ya buddy.
 
Engine dimensions

Engine dimensions

Hey nice engine. I just joined because of this thread. I'm building a CH701 and looking for a 912 alternative. Do you have the approximate dimensions of this engine? Those thrust number look very good!

Kevin
 
Hey nice engine. I just joined because of this thread. I'm building a CH701 and looking for a 912 alternative. Do you have the approximate dimensions of this engine? Those thrust number look very good!

Kevin

Post # 56 has the engine dimensions.

I have been out flying all morning, It was a perfect day with very little wind and I just was having the time of my life.
We did not have a video camera with us but next time I will remember it, I promise.

The engine just purrs and did not miss a beat, It did everything I asked of it without a single complaint.

There was a very well respected A&P mechanic out there today and when I finally came down he had to come over and "Check it out" He said he was very impressed with how the engine sounded and could not believe how smooth it sounded, I put a lot of weight in that compliment, I did not expect that, especially from him.

I have had more fun today then any other day by far, all in it was just a great day.
 
Good to hear Todd. I truly can't wait to see your machine and to fly my own. Have fun buddy.
 
Thanks, do you know if this is a dry or wet sump engine? From the dimensions I would have to lay it over to fit the 701. This would also require the 130 FI version or else the float bowl would well be sideways.
I may just be buying a Yamaha snowmobile ;-) Was the FI version ever put in the snowmobile?

Kevin


PS great work on your engine.





Post # 56 has the engine dimensions.

I have been out flying all morning, It was a perfect day with very little wind and I just was having the time of my life.
We did not have a video camera with us but next time I will remember it, I promise.

The engine just purrs and did not miss a beat, It did everything I asked of it without a single complaint.

There was a very well respected A&P mechanic out there today and when I finally came down he had to come over and "Check it out" He said he was very impressed with how the engine sounded and could not believe how smooth it sounded, I put a lot of weight in that compliment, I did not expect that, especially from him.

I have had more fun today then any other day by far, all in it was just a great day.
 
All the Yamaha sled engines are dry sump, Every engine they make are fuel injected except mine. The engine I believe you would be the most interested in would be the 130hp fuel injected engine, The only problem with that engine is they came out with it in 2007 so there are not a lot of them on the used market yet. If you wanted to go with an entire sled like I did it will probably set you back around $7,000
Here is the Yamaha website that should answer many of your questions http://www.yamaha-motor.com/sport/sno/tech_eng.aspx
 
Here is a video I promised so you can all hear my Yamaha powered Air Command. I also included some shots of when I did the thrust test a while back. I realize this is not going to be the most exciting footage you have ever seen, no crankin and bankin or anything else like that, but please remember I am still an armature in both flying gyro's and making videos. The only purpose of this is so you can hear how it sounds. http://www.youtube.com/user/crocodile98
 
That was cool, but I wish you would get in the seat next time you do the thrust test and have someone else look at your guages. You went pretty far in a short while in that video. What was your airspeed.
 
I had the gyro tied down good in three different places not including the scale attachment plus I had my hand on the kill switch, that baby was not going anywhere.
It seems to like flying at 65 to 70MPH and as you can hear in the video the engine is not straining at all, I have no idea what top speed will be, have not even began to venture there.
 
Todd,
I am sure you took precautions for the test, It just looks scary with the prop and that monstor motor burying that scale.
70 mph in an open gyro is fast to me, I don't know how you guys keep your helmet on. I think I am going to order a helmet one size smaller and try 70 mph.
Do you know what your hour fuel burn is on this engine, or are you still in the testing stage?
 
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