Run in stand/dyno build.

[Charles Perdue]

Been there....done that......
40 years ago.....

 

[LohringMiller]

Serious brake dynos are computer controlled to match the loads expected for the operating conditions. That type of dyno test gives you the above mentioned track load test and the EPA fuel mileage calculations. The inertial dynos only measure the power it takes to accelerate a given load. It's interesting to note that the rpm versus time plot on an accelerating hydro looks a lot like the curve from an inertial dyno. The load on an accelerating hydro varies as the square of the speed, though, so the load increases much more quickly.

Lohring Miller

 

[Wasted wages]

speaking of graphs and acceleration of a hydro, do you see the stuttering that happens on the dyno at about 15-17k when then motor is actually in the boat ?
Is it a byproduct of the function of the pipe ?
would trying a different pipe or pipe length prove this out ?

I think that a pipe that takes a while to two stage has to be costing time thru the traps..

 

[dwilfong]

If a flow compensating pressure relief valve is used in a hydraulic set up the pressure will stay the same as the RPMs go up.
Therefore the flow will increases as the RPM goes up keeping a steady load on the eng just like a prop in the water.
A gear in oil is just a different medium to accomplish the same function.
A load cell on a cradle and a RPM sensor will do the calculations on a graph.
Just turn the pressure up to add load.
This can be done with a electric control pressure relief valve.
You can run the eng and change loads under full throttle like you are running on the oval.
Run time would be only limited to how much fuel you have in the tank.
Make needle changes as you run make pipe adjustments as you run.
Would be much more user friendly and realistic to what are boat do.
Just a thought...........

 

[Terry Keeley]

speaking of graphs and acceleration of a hydro, do you see the stuttering that happens on the dyno at about 15-17k when then motor is actually in the boat ?
Is it a byproduct of the function of the pipe ?
would trying a different pipe or pipe length prove this out ?

I think that a pipe that takes a while to two stage has to be costing time thru the traps..

It's ragged all over. I thought this was just an issue with the data logger but it's just the nature of a single cylinder two stroke, especially worse on nitro.

The Eagle Tree only records at 10 hz with the LCD panel so it looks worse than it is, but it's still rough.

 

[Terry Keeley]

Got some tiny springs to try in the one-way bearing, it started to slip again once I ran it a bit, I'm hoping they'll fix the problem once and for all. Will try the lightest one first then have two others, it's the last thing before going to a bike freewheel.

Stock spring to the left, new ones to the right.

Made some spiders from the harder urethane, mighta beat the stock rubbers with the bearing slipping, dunno.

Added a flowmeter to the cooling system to nail down that variable too, now I just havta figure out how much water flows in the boat?

 

[Ray Sametz]

SOON TERRY!!!!!!!!

 

[Terry Keeley]

Frau Blucher!

 

[Terry Keeley]

I think I'm finally getting somewhere. The slipping one-way bearing that has plagued me for months I think is finally fixed. Thanks again to my Consigliere for coming up with the solution, I mighta got there but it would have taken me longer for sure.

Here's an rpm plot after the new bearing was run a bit, you can see the engine rpm slipping quite a bit:

Here's another plot after adding the new springs:

What a difference! The only down side might be the bearing wearing prematurely but I can live with that.

I made five full pulls tonight trying to be as consistent as possible. I'm finding the software can do weird things to the curves at the very top end and solved it so far by trimming the last 500 revs or so. I'm gonna ask them if there's another solution. I tried clicking the recorder off before and after throttling back and it didn't make any difference.

Anyway, here's the five runs together, pretty consistent really, especially looking at the torque curves and temps. I decided to not use the coast down correction as I think it's adding too much to the numbers. The data to the right is the max values between the cursors.

Here's the last run of the night, plus a little video:

 

[Terry Keeley]

Here's the latest little fire I need to put out:

So far they're only lasting 5-6 runs or so. Looking at making them from Viton or some other higher temp rubber, or possibly cooling the coupling somehow.

There's some galling on the inside where the male part contacts which is causing the heat, might be a fix there with more clearance. Interesting it's not on the driving side but the "backing off" side.

 

[Terry Keeley]

Got to see what "over center" looks like tonight.

Made a run and the power came up way short, put the flowmeter on it and I had a spec on the needle, went down to 6 1/4 from 6 3/4 on my old school meter.

Those are max values between the lines, run B (dark blue) is 4.84 hp. Interesting the temps for the lean run are way down, I think both Marty & Charles mentioned that earlier.

Video of the runs, hard to tell the second one was lean just by ear really. Keeping the coupler cool is the key to saving the rubbers.

 

[Terry Keeley]

Running in a new piston/sleeve for dyno testing, took some temps of the pipe and crankcase.

 

[RaceMechaniX]

Looks like the setup is running nicely now Terry.

 

[Terry Keeley]

Looks like the setup is running nicely now Terry.

Ya, not bad, but I'm not completely happy about the big R12 bearing supporting the clutch/one-way bearing. It only has grease lube and was never designed to turn that fast for that long and it doesn't like it, I think the heat I'm getting at the coupler might be from it. I'm gonna try it today without it, since I rubber mounted the motor & coupler I might not need it anymore.

If it doesn't work Engineering is thinking about a change...

 

[RaceMechaniX]

Terry,
Might be worth trying to replace the grease with some light oil. I also suspect that the coupler and other heat sources made causing the inner race to expand and since the outer race sits in a big block of aluminum you may be loosing all the clearance in the bearing which generates more heat.
-Tyler

 

[Terry Keeley]

Terry,
Might be worth trying to replace the grease with some light oil. I also suspect that the coupler and other heat sources made causing the inner race to expand and since the outer race sits in a big block of aluminum you may be loosing all the clearance in the bearing which generates more heat.
-Tyler

Yup, the classic snowball effect.

I'd like to feed that bearing with a drip oiler as well but the clutch is right behind it and oil there wouldn't be good. All the 6002's on the shaft are good as well as the big 6005's on the dyno wheel but this R12 has had issues, I've replaced it three times.

Here's an early pic showing the setup:

 

[RaceMechaniX]

Terry,

If you plan on running more with the ducted fan as a load can you come up with a simpler direct drive connection and remove the clutch? The clutch should only be needed for dyno pulls right, so for break in and other tests with the fan load I would think a direct drive option would be suitable.

-Tyler

BTW, I think you need to take all that beautiful tool plate and machine turn it for some additional bling factor.

 

[Steve White]

Moly?

 

[Terry Keeley]

Terry,

If you plan on running more with the ducted fan as a load can you come up with a simpler direct drive connection and remove the clutch? The clutch should only be needed for dyno pulls right, so for break in and other tests with the fan load I would think a direct drive option would be suitable.

-Tyler

BTW, I think you need to take all that beautiful tool plate and machine turn it for some additional bling factor.

Ya, that would be simpler fur shur but switching back and forth would be more complicated. Plus running the fan is a good test for the dyno wheel.

It didn't work without the supporting R12 bearing, but I did learn it's the source of the coupler heat, was cool as a cucumber without it. I guess that big bearing just doesn't like to turn 20k+. I think another 6002 with some oil drip lube is maybe what's needed.

Moly?

Was using a good German spindle bearing grease but grease and 20K+ just don't go well together I think.

 

[Terry Keeley]

Did some more work on the dyno, made a new clutch shaft from 4140HT and figured out the rubber spider issues (motor wasn't aligned properly).

Was making some pulls tonight and this!

I think the piston skirt mighta hit the crank, rod/wrist pin was getting sloppy.