Servo driver?

[RodneyPierce]

David, your onto something here man. Keep it going!!

 

[Tim_Duggan]

A rigger at full speed is under load in the turn for about 1-2 seconds.Maybe another chunk can be added for the first part of the straights. The proposed trigger being used is the elevated EGT. The EGT reading from the sensor is not instantaneous and completely in time with the entry to the corner. Small delay. Servo response rates are also going to add delay. Our fuel systems run at relatively low pressure - even with the needle valve being right at the spraybar, the EGT won't respond instantly to a change in needle setting adding more delay. Logging with a load cell dyno would be needed to establish the cumulative time delay and even then doesn't take some of the things that happen in the boat such as G forces acting upon the fuel / tank, airflow pattern inside the boat etc etc etc.

Given all of the above - what are the chances that a reactionary system is too slow? This is my main concern. Maybe a better solution is something that would reduce the delays mentioned above - for example, triggering off rudder servo input at full throttle. I know poeple have mixed the mixture control channel with rudder servo successfully in the past, just can't remember who it was.

 

[dwilfong]

Tim look at my demonstration of the thermal resistor video again. The change is almost instant.

you don't need a Dino to set this up.

The change in the needle will not have to be much to make a difference.

Now you will need to make a needle setup that runs in a certain flow percentage.

that is where the flow meter will come in to check the change in flow speed on the bench with different resistors.

Have already tested the response of a K and J coupler in my small kiln with a digital control and temp read out.

It is not as hard as you would think. the water temp rig only took a few hours to Build,set up and calibrate to get what you see in the video.

that is why I am building these simple rigs to gather date as efficiently as possible. You have to learn to crawl before you can run.

 

[Tim_Duggan]

David,

I've been thinking about these things too much without actually applying it. Have been pondering this for years and years. I have a tendency to overthink things . I blame my occupation.

Tim.

 

[dwilfong]

Hay Tim don't sweat it. i have bin thinking about it to much my self. then I just did it and it was easer than i thought.

Takes me some time to get to things but once i do it just works out.

Take a break from thinking about it and build this rig it will give you a boost just doing it to see what it dose.

 

[Tim_Duggan]

I'm off to Jaycar (Aussie equivalent to Radio Shack etc.) first thing tomorrow morning to do some component shopping. Might grab a 556 IC instead of a 555, a bit bigger but it's basically 2 x 555's in one chip. That way I can add to it

 

[dwilfong]

there you go. I have bin looking at different Thermistors and you can speck one any way you want.

This would go right in place of the 100k pot and do the same as the other rig but on the ex.

Check out what thy have in the way of a 300c Thermistor in the 50k top end range.

 

[Charles Perdue]

A CarbSmart, for $59.95 and all of the work has been done for you. Weighs only 1/4 oz.

I have one of these that I will play with when I have time.

Just mount the sensor to the cylinder at the point where the exhaust joins the fins.

Charles

 

[Jim Caldwell]

Tried one years ago, worked only on low output air-cooled motors which didn't need it anyway.

 

[Charles Perdue]

I believe that with the adjustments that it has and the placement of the temp sensor, that it will work. I can not see any reason that it would not.

I will let you know when I get to play with it.

Charles

 

[shoboat]

Charles,

Are you going to put that on your outboard set up?

You are like me that we need to get to the lake instead of working so much.

That's right I forgot you have a new lake in your backyard.

Have A Great Weekend,

Mark

 

[dwilfong]

Don't think a sensor on the out side of the case will do more than give a general reading some where between head and ex temp.

Looking for a true head temp with the sensor right in the head button and one right in the fire. these will be two different thing all together. Both will control two different things head temp on the head separated from the case with a custom cooling cap. then the actual temp of the burn taken as the gases come out of the cylinder.

I feel this will work real nice.

 

[Tim_Duggan]

I built a servo driver yesterday using the 556 IC instead of the 555, made a small mistake when converting the pin-outs for the different IC and released the magic smoke. Will have another attempt thru the week when I get a chance with no distractions.....

 

[Jim Caldwell]

David, thats exactly what we saw, Thermostat for water on exit and exhaust gas temp for mixture is where we end up after dozens of combinations.

Charles, the next best was a sensor under the plug.

 

[dwilfong]

I built a servo driver yesterday using the 556 IC instead of the 555, made a small mistake when converting the pin-outs for the different IC and released the magic smoke. Will have another attempt thru the week when I get a chance with no distractions.....

Did it look like Barbara Eden :wub:

 

[Tim_Duggan]

I built a servo driver yesterday using the 556 IC instead of the 555, made a small mistake when converting the pin-outs for the different IC and released the magic smoke. Will have another attempt thru the week when I get a chance with no distractions.....

Did it look like Barbara Eden :wub:

LOL!

Another dead Hitec in the collection. Note to self - use old crappy servo's to test driver circuits before putting them in boats!

Found something the other day that I need to look into some more as it shows promise. "Open Servo". Think arduino logic, built into a replacement servo driver board inside the servo case................ and it retrofits existing servo's!

 

[dwilfong]

Dang dude you smoked the servo to?

 

[Tim_Duggan]

Yeah - it was my own stupid fault & I should have known better. No big deal - I'm slowly phasing out and replacing all my hitecs with Futaba's anyway. MkII 556 servo driver board is nearly completed.

On a brighter note - I ran the new 21 rigger for the first time yesterday and it won it's first race ( & without water regulation too!)

 

[dwilfong]

Well I ordered the Nano today and a expansion shield

Will be a few weeks till it gets here from China.

Let the fun begin.

 

[Charles Perdue]

Don't think a sensor on the out side of the case will do more than give a general reading some where between head and ex temp.

Looking for a true head temp with the sensor right in the head button and one right in the fire. these will be two different thing all together. Both will control two different things head temp on the head separated from the case with a custom cooling cap. then the actual temp of the burn taken as the gases come out of the cylinder.

I feel this will work real nice.

A $30.00 investment in an infared thermometer, holding the back of the boat down with the prop in the water will take a lot of guess work out of where the temps are on an engine and how they change with the mixture and load. That is what I did.

If a bad theory takes you along the wrong path, there will be a lot of time and effort wasted.

If there is a way that I can test something cheaply and realitivity quick, I will do it.

But then again, that is just me.

Charles