Dyno Results?

[John Finch]

Now you went and did it Andy. Put all those variable into the picture. That was the hardest thing to control when I was testing on the dyno. Simply, you can't control those variables and yes, they do make a very big difference in the results. Nothing more depressing than to see your engine huffing and puffing on a nasty hot day in June with a pipe that worked so well when the air density was 105 on a crisp spring morning in May but is now too short. I still think the radar gun is the best investment I have ever made.

 

[AndyBrown]

Now you went and did it Andy. Put all those variable into the picture. That was the hardest thing to control when I was testing on the dyno. Simply, you can't control those variables and yes, they do make a very big difference in the results. Nothing more depressing than to see your engine huffing and puffing on a nasty hot day in June with a pipe that worked so well when the air density was 105 on a crisp spring morning in May but is now too short. I still think the radar gun is the best investment I have ever made.

Yep! John, you and I have 60 years accumalative experience and for us the answer will always be "ABOUT".

Jay is new to boating and from what I understand is a Very high level, analytical engineer by profession and knows that for every problem there is an answer, just as you and I do.

The difference is that someday, if Jay sticks with it long enough, he will have a mathematical equation to explain what you and I do by the "seat of the pants" method.

 

[jayt]

I wouldn't want to discourage anyone from trying to fit a mathematical model to reality, but extremelty elaborate software already exists to predict correct intake and exhaust configurations for full-scale two and four-stroke engines. Chrysler pioneered this software in the US auto market, designing engines on paper without the usual prototypes. The result worked well - for medium performance production engines. Even the big-budget race teams - auto and bike - still rely on dyno testing to get that last bit of power. Then they take the vehicle to the track and make more engine changes to get the lowest lap time. Even with supercomputers we're still aways from quantifying everything through mathematics....

 

[Jim Allen]

Excellent insight & truth from John & Andy. Even with a very good dyno, a good quality radar gun, & a wife willing to sit at the end of the lake during test runs with a CB, achieving consistent results is very challenging. I take my hat off to any one who has been successful in going fast!

Jim

 

[Racerdude]

Hi Andy -

Fair question (I know who put you up to this one ). I plan to collect the data from a remote telemetry system, then use the average. Since I will be able to do calculations on the data, I won't have to depend on a single data point, I can take 10,000 data points, and set things up for the average of everything. Simple.

Jay,

Are you going to program your dyno for the rough water in the back straight or the calm water in the front straight? How about the high humidity at 8:30 AM or the extra dry air at 3 PM? Or how about your fuel that is 70 degrees at 8:00 AM or 81 degrees at 5 PM. ? How about........??

Just some things to think about.

Andy

 

[Racerdude]

Hi -

Hmmmm..... Will's been talking, hasn't he?

Not really looking for the equation (although good math DOES fit reality - that's how we got practically every invention we have, including the one we are using to write these messages....), but I am wondering why the equations that are out there don't match reality relating to pipes. So, I am tackling the problem empirically. Collecting a lot of data, then using the average. Nothing complicated about using an average. I don't understand why there would be resistance against putting simple logical test techniques to work.

One other thing - throwing all of the other variable into the mix like temperature of the fuel at this time of day vs the other time, etc.... I have never seen anyone at the pond say "its 12 degrees warment than when I started this morning, so for every 12 degrees it heats up, I need to increas my pipe length by 1/2" ". It just doesn't happen. People deal with all of those variables by _guessing_ (although based on experience). I'm just finding a way to make a good guess.

If I meet the person who can say "its 12 degrees warment than when I started this morning, so for every 12 degrees it heats up, I need to increas my pipe length by 1/2, however, humidity has decreased by 10 %, so that means I need an extra 2 clicks on my mixture and another 1/4" on the pipe", I will do the best I can to understand how that is done. Until I meet someone who can do that, I will stick to simple science....

I was terribly represented. I am not planning a mathematical model. I am planning to use empirical data to derive a best setup. Sounds like everyone has math allergies. That's OK.... Think about that the next time you play "NASCAR" on your playstation.... pure math models....

 

[AndyBrown]

Jay,

Will didn't put me up to anything, nor have we even talked about this thread.

I only know of your work because Will once mentioned it.

I was just trying to help others see where your thinking was. There is nothing wrong with the math.

No body said that! jayt only mentioned that it was difficult to put it all together.

Knowing and applying the math is not the problem . There are many people like you who can handle that.

The problem is knowing just what to apply the math to. The emperical data is great. The question is, When will you know you have ALL of the emperical data?

I've been very activley at this nitro boat thing for 30 years and have been tuning and modifying nitro engines for longer than that. I still continue to find more very important and relevant varibles to throw in the pot.

Oh, and be sure to build a thermostat for your engine so the cylinder temp will remain constant.

Also be sure that your fuel line I.D. is always the same. I've seen the same size of the same brand change from one roll to the next. Yep it makes a difference!

Oh, and it takes about a tank of fuel to expel ALL of the after run oil from your crankcase, so don't expect your first run of the day to be as good as the last run from your previous outing.

Oh, and depending on the type of after run oil, the glow plug could be slightly fouled for the next run.

Oh, and.......

 

[Racerdude]

Hi Andy -

Thanks for the explanation - that helps a lot.

I am trying to figure out the best average setup. An average of the data will take into account all of the variables you mentioned.

That means some days I'll run faster than others - I understand that. All the variables you mention will have effects - some may be considerable. The good news is that I will, over a long period of time, have the optimal setup for each boat.

Anyway, if it doesn't work, then it doesn't work. One guarantee - I will learn an amazing amount about setting up boats.

Heck, I may even learn what to adjust to account for different variables.

Again, if I learn anything good, I'll let you know. If not, well then I'll just crawl back into my hole....

Thanks again!

Jay

 

[Wesleys Custom Graphics]

Jay,

Will didn't put me up to anything, nor have we even talked about this thread.

I only know of your work because Will once mentioned it.

I was just trying to help others see where your thinking was. There is nothing wrong with the math.

No body said that! jayt only mentioned that it was difficult to put it all together.

Knowing and applying the math is not the problem . There are many people like you who can handle that.

The problem is knowing just what to apply the math to. The emperical data is great. The question is, When will you know you have ALL of the emperical data?

I've been very activley at this nitro boat thing for 30 years and have been tuning and modifying nitro engines for longer than that. I still continue to find more very important and relevant varibles to throw in the pot.

Oh, and be sure to build a thermostat for your engine so the cylinder temp will remain constant.

Also be sure that your fuel line I.D. is always the same. I've seen the same size of the same brand change from one roll to the next. Yep it makes a difference!

Oh, and it takes about a tank of fuel to expel ALL of the after run oil from your crankcase, so don't expect your first run of the day to be as good as the last run from your previous outing.

Oh, and depending on the type of after run oil, the glow plug could be slightly fouled for the next run.

Oh, and.......

 

[Marty Davis]

Kevin,

Go to the Car side of CMDRACING.COM and check out the REAL race results.

The stock MAC runs good and the MOD MAC will run with any Mod anything.

MAC engine sales slowed because CMB built junk crankshafts that wore out in one gallon of fuel

and yes, after the first gallon they got spanked because the crank pin diameter is reduced by .003".

That is the precise reason CMB no longer builds MAC engines.

Wow......do you have issues or what???

Andy:

I didn't know that CMB was no longer the manufacturer of MAC's. That is REALLY good news. Who is building them now?

Marty Davis

Hey marty its spanky andys b-inlaw blow some dust off of those boats like i did lets RACE

As a matter of fact, I am going up to the shop where all my old stuff is (Dyno too) Friday and Saturday to teach someone how to build sponsons. I REALLY enjoyed going to the race in Brandon and seeing the few old timers.

Dr. Callahan is coming for Thanksgiving (Andy's best buddy).

Marty Davis

Hi Andy -

Thanks for the explanation - that helps a lot.

I am trying to figure out the best average setup. An average of the data will take into account all of the variables you mentioned.

That means some days I'll run faster than others - I understand that. All the variables you mention will have effects - some may be considerable. The good news is that I will, over a long period of time, have the optimal setup for each boat.

Anyway, if it doesn't work, then it doesn't work. One guarantee - I will learn an amazing amount about setting up boats.

Heck, I may even learn what to adjust to account for different variables.

Again, if I learn anything good, I'll let you know. If not, well then I'll just crawl back into my hole....

Thanks again!

Jay

Jay:

What you are doing is the SAME THING that Andy, John Finch and Myself also have done. We just didn't have the engineering background to save us time. What you have stated is great for your understanding of this VERY COMPLEX hobby, but there is nothing that will help you like trial and error. You will VERY QUICKLY learn that those things that you do incorrectly will stick with you longer than those that you do correctly.

Another variable of some significance is the ability to connect that great brain to the transmitter. THAT will take some time to get proficient.

Since I am entertaining Dr Callahan over Thanksgiving, I will also be hearing a lot of the same things from him. Hard to follow some times......

I would enjoy being around you and hearing your ideas and methods of saving time. I NEVER have enough of that.

Marty Davis

Marty,

We are building them here in the USA.

More details about this later.

Careful Marty! Don't get me started on an over Hyped Sales Pitch! LOL

Andy:

Any change in appearance? Bar stock CNC cases, etc? Images on the internet?

Marty

 

[chuck h]

Kevin,

Go to the Car side of CMDRACING.COM and check out the REAL race results.

The stock MAC runs good and the MOD MAC will run with any Mod anything.

MAC engine sales slowed because CMB built junk crankshafts that wore out in one gallon of fuel

and yes, after the first gallon they got spanked because the crank pin diameter is reduced by .003".

That is the precise reason CMB no longer builds MAC engines.

Wow......do you have issues or what???

Andy:

I didn't know that CMB was no longer the manufacturer of MAC's. That is REALLY good news. Who is building them now?

Marty Davis

Hey marty its spanky andys b-inlaw blow some dust off of those boats like i did lets RACE

As a matter of fact, I am going up to the shop where all my old stuff is (Dyno too) Friday and Saturday to teach someone how to build sponsons. I REALLY enjoyed going to the race in Brandon and seeing the few old timers.

Dr. Callahan is coming for Thanksgiving (Andy's best buddy).

Marty Davis

Hi Andy -

Thanks for the explanation - that helps a lot.

I am trying to figure out the best average setup. An average of the data will take into account all of the variables you mentioned.

That means some days I'll run faster than others - I understand that. All the variables you mention will have effects - some may be considerable. The good news is that I will, over a long period of time, have the optimal setup for each boat.

Anyway, if it doesn't work, then it doesn't work. One guarantee - I will learn an amazing amount about setting up boats.

Heck, I may even learn what to adjust to account for different variables.

Again, if I learn anything good, I'll let you know. If not, well then I'll just crawl back into my hole....

Thanks again!

Jay

Jay:

What you are doing is the SAME THING that Andy, John Finch and Myself also have done. We just didn't have the engineering background to save us time. What you have stated is great for your understanding of this VERY COMPLEX hobby, but there is nothing that will help you like trial and error. You will VERY QUICKLY learn that those things that you do incorrectly will stick with you longer than those that you do correctly.

Another variable of some significance is the ability to connect that great brain to the transmitter. THAT will take some time to get proficient.

Since I am entertaining Dr Callahan over Thanksgiving, I will also be hearing a lot of the same things from him. Hard to follow some times......

I would enjoy being around you and hearing your ideas and methods of saving time. I NEVER have enough of that.

Marty Davis

Marty,

We are building them here in the USA.

More details about this later.

Careful Marty! Don't get me started on an over Hyped Sales Pitch! LOL

Andy:

Any change in appearance? Bar stock CNC cases, etc? Images on the internet?

Marty

There is some good information here, good thread, thanks.....

http://wahiduddin.net/calc/cf.htm

http://wahiduddin.net/calc/density_altitude.htm

 

[AndyBrown]

Andy:

Any change in appearance? Bar stock CNC cases, etc? Images on the internet?

Marty

Yes Marty several Big improvements for the MAC USA. Both in materials and design.

The A/A Pro, which we will have the .21 first, will be at yet a higher level than the MAC USA.

Don't want to give out too much detail until they are nearly ready.

Also coming soon is the A Cubed .21. This engine is also a much improved engine over the old MAC.

Replacement P/L's for the old MAC will also be improved.

 

[John Knight]

Jay,

Will didn't put me up to anything, nor have we even talked about this thread.

I only know of your work because Will once mentioned it.

I was just trying to help others see where your thinking was. There is nothing wrong with the math.

No body said that! jayt only mentioned that it was difficult to put it all together.

Knowing and applying the math is not the problem . There are many people like you who can handle that.

The problem is knowing just what to apply the math to. The emperical data is great. The question is, When will you know you have ALL of the emperical data?

I've been very activley at this nitro boat thing for 30 years and have been tuning and modifying nitro engines for longer than that. I still continue to find more very important and relevant varibles to throw in the pot.

Oh, and be sure to build a thermostat for your engine so the cylinder temp will remain constant.

Also be sure that your fuel line I.D. is always the same. I've seen the same size of the same brand change from one roll to the next. Yep it makes a difference!

Oh, and it takes about a tank of fuel to expel ALL of the after run oil from your crankcase, so don't expect your first run of the day to be as good as the last run from your previous outing.

Oh, and depending on the type of after run oil, the glow plug could be slightly fouled for the next run.

Oh, and.......

I absolutely love this discussion! It just shows us mere mortals how little we know when these long term experts still don't have all of the answers. I am firmly convinced, that no matter how hard we work, how detailed we become, etc., we will be still chasing our tails 20/30 years from now. The improvements in technology will carry us but so far. There are so many variables that we cannot control that significantly influence our racing. That does not take into account the human element, which is the greatest variable of all. However, let's keep plugging away and improve those things we can.

Andy & John, love your sage advice! Crank Marty into the equation and we have a group of masters like no other. Wow!

 

[Tom Foley]

First of all I cannot say enough , thank you, to MartyDavis for putting into print some very usefull informaton about props and the fearless modification of them from a given casting shape , which in their own right , are very functional off the shelf part for the average boater . Secondly and no less importantly , the ability to buy custom balanced , sharpened and application cupped and pitched props from CMDI and Randy Sampson, Bobby Austin ,among others is absolutely amazing to me !!

Furthermore , The fact that ANYONE is venturing into the manufacture of something so detail driven as a motor program for a coulple of thousand , maybe , motor sales speaks volumes for dedication and enthusiasm of a relatively small hobby such as RC boat racing . Andy , John , Crew , ...... PLEASE build a torquey , rev - happy motor line with backup parts to finally shut up these computer pussys that whine about everything, but in their own lives accomplish little !!!!!!! Tom .

 

[Racerdude]

Jay:

What you are doing is the SAME THING that Andy, John Finch and Myself also have done. We just didn't have the engineering background to save us time. What you have stated is great for your understanding of this VERY COMPLEX hobby, but there is nothing that will help you like trial and error. You will VERY QUICKLY learn that those things that you do incorrectly will stick with you longer than those that you do correctly.

Hi Marty -

That is right. What others have done by feel, I am simply going to do with data. There is a reason why people thing pipe length of X is good. That's because they have already collected the data and sort of "averaged" it all together in their heads. They did it by trial and error. I have done a lot of trial and error, but I don't have 30 years to wait to run well!

Again, I'll let you know how well it works when I'm done!

Take care -

Jay

 

[Marty Davis]

Jay:

What you are doing is the SAME THING that Andy, John Finch and Myself also have done. We just didn't have the engineering background to save us time. What you have stated is great for your understanding of this VERY COMPLEX hobby, but there is nothing that will help you like trial and error. You will VERY QUICKLY learn that those things that you do incorrectly will stick with you longer than those that you do correctly.

Hi Marty -

That is right. What others have done by feel, I am simply going to do with data. There is a reason why people thing pipe length of X is good. That's because they have already collected the data and sort of "averaged" it all together in their heads. They did it by trial and error. I have done a lot of trial and error, but I don't have 30 years to wait to run well!

Again, I'll let you know how well it works when I'm done!

Take care -

Jay

Dr Callahan arrived and my head is already spinning. We stayed up very late last night talking about all kind of things model boating related. This the first time that I have had a chance to talk to him person to person and is is just like we left off a couple years ago. I wish that I had time to apply the many ideas that hes has. Wait till you see the engine that he is building. It will probably obsolete anything we have ever seen. Also talked him into sharing the formula for balancing a single cyl model engine. That will be something I will make available soon. Can't wait to get to the shop tomorrow.....

Marty Davis

 

[Tom Foley]

Jay:

What you are doing is the SAME THING that Andy, John Finch and Myself also have done. We just didn't have the engineering background to save us time. What you have stated is great for your understanding of this VERY COMPLEX hobby, but there is nothing that will help you like trial and error. You will VERY QUICKLY learn that those things that you do incorrectly will stick with you longer than those that you do correctly.

Hi Marty -

That is right. What others have done by feel, I am simply going to do with data. There is a reason why people thing pipe length of X is good. That's because they have already collected the data and sort of "averaged" it all together in their heads. They did it by trial and error. I have done a lot of trial and error, but I don't have 30 years to wait to run well!

Again, I'll let you know how well it works when I'm done!

Take care -

Jay

Dr Callahan arrived and my head is already spinning. We stayed up very late last night talking about all kind of things model boating related. This the first time that I have had a chance to talk to him person to person and is is just like we left off a couple years ago. I wish that I had time to apply the many ideas that hes has. Wait till you see the engine that he is building. It will probably obsolete anything we have ever seen. Also talked him into sharing the formula for balancing a single cyl model engine. That will be something I will make available soon. Can't wait to get to the shop tomorrow.....

Marty Davis

Although I do not posess the depth of understanding as the above state individuals , it seems logical that a reliable movable pipe system is part of the answer to a more drivable and top-end capable boat . Pro Outboards have been using this for decades to be able to "pull the pipes " for the shot down the chute . I know it would be a pain in the as , but a robust third channel system to pull or extend the pipe , even on a timer of some kind would be revolutionary .

 

[ids987]

Although I do not posess the depth of understanding as the above state individuals , it seems logical that a reliable movable pipe system is part of the answer to a more drivable and top-end capable boat . Pro Outboards have been using this for decades to be able to "pull the pipes " for the shot down the chute . I know it would be a pain in the as , but a robust third channel system to pull or extend the pipe , even on a timer of some kind would be revolutionary .

Tom,

One man's way of doing it....Servo Adjustable Pipe

Ian

 

[Tom Foley]

Although I do not posess the depth of understanding as the above state individuals , it seems logical that a reliable movable pipe system is part of the answer to a more drivable and top-end capable boat . Pro Outboards have been using this for decades to be able to "pull the pipes " for the shot down the chute . I know it would be a pain in the as , but a robust third channel system to pull or extend the pipe , even on a timer of some kind would be revolutionary .

Tom,

One man's way of doing it....Servo Adjustable Pipe

Ian

Thats it !

 

[gil sonsino]

What a thread.............my brain is spinning in the high K's.....there 's so many variables we have to consider and put on the paper..... but nothing better than thousand hours spent on the lake .......the more I learn the less I know .............fantastic discussion

Thanks

Gill