Yamaha 120-150 HP Conversion Kits For Sale

Greg, Your kit looks professional and beefy. Will you be selling an exhaust kit? Also, from your research how plentiful (easy to get/costly) are the yamaha motors?
 
Yes, there are two exhaust headers to choose from. One is the gyro style on my Air Command, the other is a tighter wrap-around intended for FW. The one I used on my gyro is more efficient, and flows a bit more HP than the shorter FW style.

The lower-end, "routinely-available" price range to buy a suitable sled is $3000 - $5000, and it goes up from there for the newer model years.

I am going to purchase a few sleds, strip them, do leak down tests, bead blast the engines, polish, cut and rework the headers, align and attached the PSRU, and sell the whole thing like Viking does - as a bolt-on, turnkey aero engine kit. This will include a brand new aluminum double-thick Honda racing radiator like I am using now, silicon reducers and hose to adapt that to the Yamaha cooling pipes, attach and route the various hoses, wiring, coolant lines, reservoirs etc., and lengthen the wiring harness so you can mount the tach on the panel. Oh, and don't forget the rotor tach sensor that puts your RRPM on the speedo on the Yamaha Tach LCD, the oil level sensor, and temp

There is a very good chance - 99% - that I won't be selling individual parts for very long; just for now, until I get the integrated PSRU sorted out. Once that happens, I will only be selling complete bolt-on conversions.

The 2013 plan is complete the new PSRU, then build a Dominator Mast, Mains and rear keel to jig a suitable mounting kit for that frame. Sport Copter is probably next in line, then who knows what will come after that. Maybe a FW firewall.

But the lynchpin right now is completing the PSRU.
 
It's been suggested to me by someone more knowledgeable that the engine could be damaged by holding the engine at its RPM of maximum torque using prop loading, even under ambient pressure. Ron, I stand corrected!

No problems.... Maybe manifold pressure wasn't the best words to use, but whatever you want to call it, you don't want to to choke down a 150hp engine to 100hp by putting a ton of twist into the blades.

A better way to achieve this would be to set the pitch of the prop to where ever it needs to be to achieve the engines rated rpm limit ( or slightly lower, perhaps 9500 in the case of Gergs engine ) And then somehow installing a throttle stop on the throttle quadrant that limits the max amount of throttle that can be applied, to only allow the engine to reach whatever target RPM / HP rating you want. Perhaps 150hp is at 10,500 rpm, and 100 hp is at 8500 rpms.... don't twist the prop blades to the point where the engine at WOT will only do 8500, instead twist the blades so the engine can get to around 10,000 rpms and then pull the throttle back till the engine is only running 8500 rpm, and that is where you need to put a throttle stop so the lever can't be pushed any further forward.

Personally, I see no reason not to use all the HP the engine has. No one is going to put this engine on a light single seater, so it will be likely its a two seater or a heavy single place... and in that case, just use the engine wisely and when you need 150 hp its there and when you only need 100 or even 70, you get to throttle WAY back and enjoy a low rpm and low fuel burn, less noise etc...
 
It's nice to see you sharing your development work where all can benefit. The setup looks promising.

Where the HP and Torque curves cross on your graph are arbitrary and depend on the scale of units used. The most efficient point with lowest specific fuel consumption is usually at max torque. 10,000 rpm looks like a good red line. If it is, plan on ground running at least a few hours at max rpm to verify all is well

If you are starting with a clean sheet you might consider this approach. Establish what is the max diameter of prop you can use. Efficiency of low speed gyros usually benefit from large props (stability issues excepted). Gear the prop to about 2500 rpm which in your case would mean a 4:1 ratio. If you go with a lower rpm you will make less noise. A higher rpm up to a limit of 65% mach tip speed will make more noise. Now the hard part. Select a prop AF (activity factor is similar to solidity ratio on a rotor and is adjusted by blade width or number of blades) that will absorb the power at 10,000 engine rpm. Finally set the blade pitch to give about 9500 engine rpm static.

Dino
 
Where the HP and Torque curves cross on your graph are arbitrary and depend on the scale of units used. The most efficient point with lowest specific fuel consumption is usually at max torque.
Dino

In my opinion the torque in foot pounds and horsepower plots always cross on a graph at 5,252 RPM because horsepower equals foot pounds of torque times rpm divided by 5,252.

It is my observation many things beyond torque peak govern the RPM where the Brake Specific fuel Consumption is lowest.

Regards, Vance
 
It's nice to see you sharing your development work where all can benefit. The setup looks promising.

Where the HP and Torque curves cross on your graph are arbitrary and depend on the scale of units used. The most efficient point with lowest specific fuel consumption is usually at max torque. 10,000 rpm looks like a good red line. If it is, plan on ground running at least a few hours at max rpm to verify all is well

If you are starting with a clean sheet you might consider this approach. Establish what is the max diameter of prop you can use. Efficiency of low speed gyros usually benefit from large props (stability issues excepted). Gear the prop to about 2500 rpm which in your case would mean a 4:1 ratio. If you go with a lower rpm you will make less noise. A higher rpm up to a limit of 65% mach tip speed will make more noise. Now the hard part. Select a prop AF (activity factor is similar to solidity ratio on a rotor and is adjusted by blade width or number of blades) that will absorb the power at 10,000 engine rpm. Finally set the blade pitch to give about 9500 engine rpm static.

Dino

I think you might be overlooking the YG4's internal gearing, 1.19:1. For example, when the engine is turning 6000 RPM the counter shaft (crankshaft does not protrude outside the case) is only turning 5000 RPM.

We are working with Warp Drive to get the most out of the setup. Daryl thinks anywhere between 2.80:1 and 2.90:1 is going to work best with his props. With my GTX PSRU I will be able to swap ratios for just $40.00 each step, in 5 to 10 minutes.

Standard recommended ratios for my GTX YG4 will be 2.58:1, 2.72:1, 2.88:1. I am running 2.53:1 now, and find it can be a real fuel miser, while still being climb monster. The power band is just ridiculous. So even the next gen 2.58:1 is going to be VERY desirable. I won't be surprised if many folks spend the relatively few extra bucks and buy the complete set of three drive gears, to have the option of playing with the ratios.

Other ratios available for use with other engines can go in one-tooth increments larger on the drive wheel, all the way down to 1.50:1
 
Last edited:
Sleds for sale today

Sleds for sale today

Here's what is available today. These are dealers, so there are title and dealership fees, but sales tax won't apply since I am out of state.

(I like dealers rather than private sellers, since they are ready to crate and ship at a moment's notice, and the couple extra bucks in paperwork fees more than pays for itself off when it comes to shipping, the freight companies charge that much less since they are also dealing with commercial locations that have docks and lifts.


Carburetor models:

$3000, 5k mi + $500 title, S/H
$3200, 4k mi + $500 title, S/H
$3200, 7.6k mi + $500 title, S/H

FI Models:
$4000, 3.1k mi + $600 title, S/H
$4500, 6.6k mi + $600 title, S/H
$4500, 10.7k mi + $600 title, S/H
$4500, 5.1k mi + $600 title, S/H
$4500, 7.5k mi + $600 title, S/H
$4800, TBD mi + $500 title, S/H


Air Trikes PSRU, delivered from Canada, $1800

Pressure Clutch (not centrifugal) w/flexible coupling, $500

PSRU adapter, complete engine mounting kit, and double-thick core aluminum racing radiator w/cooling lines $2000

Complete SS Exhaust kit with muffler, EGT sensors (4), and vibration damping mounting system $1000

Engine prep (includes removal, bead blasting & polishing, and all custom work to adapt engine, ancillaries and electricals for gyrocopter installation, leak-down test data, & complete tune-up) $1000

Final S/H to your shop $199

TOTAL DELIVERED PRICE, ready to bolt-on to your mast and keel including engine from the lowest-price listed sled above:

$9999.00

Prices subject to change without notice, call for latest pricing.
 
Last edited:
How many hours do you have on the engine / PSRU combination as described in your pricing example?


Here's what is available today. These are dealers, so there are title and dealership fees, but sales tax won't apply since I am out of state.

(I like dealers rather than private sellers, since they are ready to crate and ship at a moment's notice, and the couple extra bucks in paperwork fees more than pays for itself off when it comes to shipping, the freight companies charge that much less since they are also dealing with commercial locations that have docks and lifts.


Carburetor models:

$3000, 5k mi + $500 title, S/H
$3200, 4k mi + $500 title, S/H
$3200, 7.6k mi + $500 title, S/H

FI Models:
$4000, 3.1k mi + $600 title, S/H
$4500, 6.6k mi + $600 title, S/H
$4500, 10.7k mi + $600 title, S/H
$4500, 5.1k mi + $600 title, S/H
$4500, 7.5k mi + $600 title, S/H
$4800, TBD mi + $500 title, S/H


Air Trikes PSRU, delivered from Canada, $1800

Pressure Clutch (not centrifugal) w/flexible coupling, $500

PSRU adapter, complete engine mounting kit, and double-thick core aluminum racing radiator w/cooling lines $2000

Complete SS Exhaust kit with muffler, EGT sensors (4), and vibration damping mounting system $1000

Engine prep (includes removal, bead blasting & polishing, and all custom work to adapt engine, ancillaries and electricals for gyrocopter installation, leak-down test data, & complete tune-up) $1000

Final S/H to your shop $199

TOTAL DELIVERED PRICE, ready to bolt-on to your mast and keel including engine from the lowest-price listed sled above:

$9999.00

Prices subject to change without notice, call for latest pricing.
 
Yeah, when you add everything up like this, for a complete turnkey bolt on, I have to absorb some of the final S/H to keep it under $10k and not be making the same as if I were flipping burgers at Micky D's...not that there's anything wrong with working for min wage at MacDonalds, they make more than I do these days!
 
My kit, with an Arrow PSRU and sprag clutch, is at 23 hours this morning, it'll be more this afternoon :) I did a 1.5 hr cross country (my third in this ship) to another airport yesterday.

The clutch I am describing here has not been tried on this setup yet, this post above is to provide a proper price in response to the requests for that. I think a lot of people are thinking, planning, setting goals etc.
 
Here's what is available today. These are dealers, so there are title and dealership fees, but sales tax won't apply since I am out of state.

(I like dealers rather than private sellers, since they are ready to crate and ship at a moment's notice, and the couple extra bucks in paperwork fees more than pays for itself off when it comes to shipping, the freight companies charge that much less since they are also dealing with commercial locations that have docks and lifts.


Carburetor models:

$3000, 5k mi + $500 title, S/H
$3200, 4k mi + $500 title, S/H
$3200, 7.6k mi + $500 title, S/H

FI Models:
$4000, 3.1k mi + $600 title, S/H
$4500, 6.6k mi + $600 title, S/H
$4500, 10.7k mi + $600 title, S/H
$4500, 5.1k mi + $600 title, S/H
$4500, 7.5k mi + $600 title, S/H
$4800, TBD mi + $500 title, S/H

.

Dealer just got back to me with mileage on the last sled: 2500mi.

Also, good chance I can get Neil's PSRU for quite a bit less than the guy in Canada, but need to talk to him and make sure the prices we discussed last time are going to be good, or similar.
 
Last edited:
I've got (3) carbed 4 cylinder motors and (3) FI 4 cylinder motors in stock.

$1600 for a carbed motor kit (motor, electronics, harness, fuel tank and pump, t-stat housing, coolant tank, air box, carbs & exhaust flex joints)

$2000 for an Fi motor kit ( motor, electronics, harness, fuel tank with pump, t-stat housing, coolant tank, air box, t-bodies, & exhaust flex joints)
 
This seems like a pretty good deal. SS Motorcycle headers will fit those engines and only run about $1000 new. Does the tach/instrument cluster come with the wiring harness, rectifier, fuses and EFI?

How do you verify mileage/hours on the engines if they are already out of the sleds?

Are they rebuilt? Cleaned up? Just out of curiosity, how did you come by so many engines?
 
Last edited:
This seems like a pretty good deal. SS Motorcycle headers will fit those engines and only run about $1000 new. Does the tach/instrument cluster come with the wiring harness, rectifier, fuses and EFI?

How do you verify mileage/hours on the engines if they are already out of the sleds?

Are they rebuilt? Cleaned up? Just out of curiosity, how did you come by so many engines?


I run a snowmobile salvage business that deals only with yamaha sleds. I will respond to your PM.
 
For $10 you can get a Lycoming. Less moving parts = better reliability.
 
Do you have any drawings for the Arrow gearbox? I would like to adapt one to a BMW oilhead.
 
Top