Run in stand/dyno build.

[RaceMechaniX]

OS came out with an automatic needle in the form of a fuel injected throttle body replacing the carb. They used it on the 140RX-FI, 160RX-FI and the 4-stroke Surpass FS-91 FI. They had a RPM sensor plus a cylinder head temp sensor and the mini computer also inputted the throttle signal for reference. A very slick little design they only produced briefly. I have one of the Surpass engines to play with.

 

[dwilfong]

OS came out with an automatic needle in the form of a fuel injected throttle body replacing the carb. They used it on the 140RX-FI, 160RX-FI and the 4-stroke Surpass FS-91 FI. They had a RPM sensor plus a cylinder head temp sensor and the mini computer also inputted the throttle signal for reference. A very slick little design they only produced briefly. I have one of the Surpass engines to play with.

View attachment 287120

I always wanted to get one a play with it.
Spurred many day dreams for me at one time.
I have a Arduino board that I was going to use to build my own FI system for Nitro.
I built a water control with a 555 timer chip and a thermal resistor to work a servo to control a Perry vale.
That was a fun project.
The only problem is I am not able to wright the codes and compile them to make a control system.
Even specked a small pump to control the fuel flow to the eng.
Tried to find some one who was fluent at it but was not in the cards.
May try it again when I have the time and motivation to do it.
Direct cylinder injection is the end game planted in my head by Andy Brown.
Terry you have a great chance to explore many different things with this Dyno.
Cant wait to see what you try.

 

[dwilfong]

her you go.
WOW 8 years ago .....seamed like yesterday.

 

[Terry Keeley]

OS came out with an automatic needle in the form of a fuel injected throttle body replacing the carb. They used it on the 140RX-FI, 160RX-FI and the 4-stroke Surpass FS-91 FI. They had a RPM sensor plus a cylinder head temp sensor and the mini computer also inputted the throttle signal for reference. A very slick little design they only produced briefly. I have one of the Surpass engines to play with.

View attachment 287120

Interesting. I looked at the manual Pdf Download | O.S. Engines FS-91 II FI User Manual (29 pages) and it's not clear if the unit adjusts the mixture "closed loop"? In other words would it richen the mixture if the airplane went vertical for example?

Looks like it might just have a red/green light for rich/lean based off rpm and head temp?

 

[Terry Keeley]

her you go.
WOW 8 years ago .....seamed like yesterday.

That's it. So you used an Arduino to control it? Care to share the circuit?

 

[dwilfong]

That's it. So you used an Arduino to control it? Care to share the circuit?

It is a simple 555 timer chip and a few resistors.
I will see if I can dig up the circuit diagram.
I just googled it and found one.
https://en.wikipedia.org/wiki/555_timer_ICVery rudimentary.
I have worked on DC servo controls my whole life on aerial lifts.

 

[dwilfong]

Just insert a thermal resistor in place of the pot as your variable resistance..
Just google it and look under pictures and it will show many variations of this.

 

[Jeff Burford]

I used to race supekart . 250 cc GP engines 2 cylinder 2 stroke running on 100 octane. We used EGT temps to tune the cylinders, as each cylinder was an independant induction system . EGTs were in the range of 700 -800 degrees. Changing a jet size in 1 carby would net approx 15 degree heat change in that cylinder, so if cylinder1 was at 715 and cylinder 2 was at 745 degrees then we would either jet cyl1 down 2 jets , or richen up cylinder 2 by 2 jets. With dyno time, you can work out the best fuel ratio for max power.
We used the dyno to test pipe design. It also is useful for testing ignition timing, for programmable ignition systems. Dyno time for us was limited to how deep your pockets were.The numbers dont really matter, ( so scale isnt that important)its being able to see and predict the change in performance. One dyno setup we regularly used gave us a generous 105HP reading, while another gave us 95HP on the same setup. Bragging rights of course, dictate quoting the first set of numbers...

 

[Terry Keeley]

View attachment 287126

Just insert a thermal resistor in place of the pot as your variable resistance..
Just google it and look under pictures and it will show many variations of this.

Thanks, looks pretty simple. Instead of using resistance there must be a way to input the voltage from an amplified thermistor in the pipe.

I'm confirming just running the fan what I thought for years, controlling the water to the head is a way to get a broad range of temperature but nothing trumps the change made by the needle. I think EGT would be a much better way to control a variable needle...

 

[Terry Keeley]

Got the wheel back from balancing, they said it didn't take much, I tried to follow what he was saying but didn't quite understand.

I think what they do is measure how much out of balance each shaft is as it's spun up? The left side (shown here) was out the most at 0.665g and they brought it to 0.044g? The other side only had one little dimple. Maybe Mark or Tyler can shed some light on this?

 

[Steve White]

^^^ Probably dynamic balancing, to reduce the tendency to wobble. Same concept used in wheel/tire balancing with the weight placement.

 

[Steve White]

I used to race supekart . 250 cc GP engines 2 cylinder 2 stroke running on 100 octane. We used EGT temps to tune the cylinders, as each cylinder was an independant induction system . EGTs were in the range of 700 -800 degrees. Changing a jet size in 1 carby would net approx 15 degree heat change in that cylinder, so if cylinder1 was at 715 and cylinder 2 was at 745 degrees then we would either jet cyl1 down 2 jets , or richen up cylinder 2 by 2 jets. With dyno time, you can work out the best fuel ratio for max power.
We used the dyno to test pipe design. It also is useful for testing ignition timing, for programmable ignition systems. Dyno time for us was limited to how deep your pockets were.The numbers dont really matter, ( so scale isnt that important)its being able to see and predict the change in performance. One dyno setup we regularly used gave us a generous 105HP reading, while another gave us 95HP on the same setup. Bragging rights of course, dictate quoting the first set of numbers...

In the 125cc (Rotax & TM shifter) classes we set the EGT sensor 6" from the edge of the sleeve. With Phillips 101 race gas we looked for ~1150F at the end of the straights. On a grand prix style sprint track the EGT readings vary ~200F through the lap, and peaks out at the end of the straights.

 

[dwilfong]

Thanks, looks pretty simple. Instead of using resistance there must be a way to input the voltage from an amplified thermistor in the pipe.

I'm confirming just running the fan what I thought for years, controlling the water to the head is a way to get a broad range of temperature but nothing trumps the change made by the needle. I think EGT would be a much better way to control a variable needle...

Yes you could adapted the k coupler to work in placed of the pot.
I will do some research and see if I can come up with circuit that will work.
I have all the stuff to work with.
I think I can make a unit that will pug in between the receiver 3rd channel and the needle control servo.
If I can I will send it your way to test.

 

[dwilfong]

In the 125cc (Rotax & TM shifter) classes we set the EGT sensor 6" from the edge of the sleeve. With Phillips 101 race gas we looked for ~1150F at the end of the straights. On a grand prix style spring track the EGT readings vary ~200F through the lap, and peaks out at the end of the straights.

That is more in line with what a gas eng should see. 1150 is the max you want to be safe.
My V6 Merc with a Brucato tune on the FI ran 1050F on the safe side.
That was 2" after the exit of the ex chest.

 

[shoboat]

Terry,

I know of a guy down in Bolivar, Tennessee that knows quite a bit
about EGT systems. Hopefully he will read this post and chime in.

You Are Going All In On This Project,
Very Impressive Terry,

Mark Sholund

 

[LohringMiller]

The mixture system I tried simply tried to maintain a set EGT by enriching the mixture if the EGT increased and leaning the mixture if the EGT decreased. It quit being made a long time ago. I traded it to Skip Wagner at the 1998 Nationals.

Today we have a lot better cheap micro controllers and can look at a lot of inputs. The two issues are sorting out the influence from a variety of inputs and getting good fuel mixing in a very short time. The current thinking for direct injection favors injectors on the transfers shooting into the incoming flow. Orbital style systems aren't good for high rpm and cylinder head injection is better, but still not suitable at high rpm, even with a Crecy style prechamber. Throttle body injection looks like the way industrial two strokes are headed, but cost is a factor. Some very knowledgeable two stroke guys have been working on injection systems for high performance engines. See Speeduino 2T EFI Project

Lohring Miller

 

[Mark Bullard]

Got the wheel back from balancing, they said it didn't take much, I tried to follow what he was saying but didn't quite understand.

I think what they do is measure how much out of balance each shaft is as it's spun up? The left side (shown here) was out the most at 0.665g and they brought it to 0.044g? The other side only had one little dimple. Maybe Mark or Tyler can shed some light on this?

The 30,000 is the max speed you requested to be balanced at. The correction radius is where they drilled to balance from the center on the mass. The Initial amount is how much it is out. Do not know if it oz's or grams. Grams of course is a tighter balance. The final amount is how much they balance to. The question is what was the spec. I know on my machines that a G 1 spec would be somewhere in the area of .00# in grams. A G 0.04 spec would be even lower. Here is a picture and a video of my large machine. You can't really see it but the small machine is behind the console. Also my machines print the job with all the numbers.


View attachment KVID0493.mp4

 

[Terry Keeley]

Yes you could adapted the k coupler to work in placed of the pot.
I will do some research and see if I can come up with circuit that will work.
I have all the stuff to work with.
I think I can make a unit that will pug in between the receiver 3rd channel and the needle control servo.
If I can I will send it your way to test.

No need to build it yourself, maybe if you come across some info post it here? This is something I'm possibly looking at for down the road.

The mixture system I tried simply tried to maintain a set EGT by enriching the mixture if the EGT increased and leaning the mixture if the EGT decreased. It quit being made a long time ago. I traded it to Skip Wagner at the 1998 Nationals.

Today we have a lot better cheap micro controllers and can look at a lot of inputs. The two issues are sorting out the influence from a variety of inputs and getting good fuel mixing in a very short time. The current thinking for direct injection favors injectors on the transfers shooting into the incoming flow. Orbital style systems aren't good for high rpm and cylinder head injection is better, but still not suitable at high rpm, even with a Crecy style prechamber. Throttle body injection looks like the way industrial two strokes are headed, but cost is a factor. Some very knowledgeable two stroke guys have been working on injection systems for high performance engines. See Speeduino 2T EFI Project

Lohring Miller

That's what I'm thinking exactly, it would "tune" the needle to keep a constant EGT as the other factors tried to change it. It would probably be best to have some sort of throttle position input as well so it only was "active" at full throttle.

It could richen the mixture when the boat goes around a corner, keep it from going lean at the end of the straight away, compensate if a little speck of dirt got in the needle or cooling system etc. etc. Plus you could travel anywhere or run in any air and the needle would be bang on.

Hmmmm....

 

[RaceMechaniX]

I think the balance report indicates it will be run in Terry's dyno up to 30kRPM. I would seriously question if they tried to spin that large of a flywheel much beyond 2kRPM. When I balanced rotors of this size it didn't take any more than 1000RPM to accurately measure the imbalance.

Mark's motor and mine are on polar opposite sides of the spectrum. Mark's probably run in the 100's to 1000's of RPM range and mine in the 80,000-250,000RPM range. The balance weights welded on the rotor in the video are heavier than some of my rotors. And of course his motors are a little more powerful.

 

[Terry Keeley]

The 30,000 is the max speed you requested to be balanced at. The correction radius is where they drilled to balance from the center on the mass. The Initial amount is how much it is out. Do not know if it oz's or grams. Grams of course is a tighter balance. The final amount is how much they balance to. The question is what was the spec. I know on my machines that a G 1 spec would be somewhere in the area of .00# in grams. A G 0.04 spec would be even lower. Here is a picture and a video of my large machine. You can't really see it but the small machine is behind the console. Also my machines print the job with all the numbers.

Serious stuff!

Ya, he talked grams. Spec was G1.0.

I think they might be using g-in, I found a formula on pg. 5 here:

https://irdproducts.com/assets/balance_quality_requirements_of_rigid_rotors.pdf
If you plug in 32 lbs. and 30K you get a max for G1.0 of 0.182 g-in.