Air Density

[bmazor]

I have found that the Boris Gen 4 meter will take about 99.9% of the guess work out of going from site to site. I have a small weather station and a air density meter that do not even use any more.

So it must compensate for Humidity, Density-Altitude, Water temperature, Air Temperature, Fuel Temperature, anyone of which alone can effect fuel mixture burn much more than 1%.

Just asking, as I have not seen the Gen 4 system.

You are right! The GEN-4 flow meter uses current air condition. Boris

 

[Jerry T]

My Gen 3 Boris meter seems to do the same thing, sold my Kinsler Air Density gauge long ago. I don't think I could race if you took my Boris meter away.

 

[bmazor]

My Gen 3 Boris meter seems to do the same thing, sold my Kinsler Air Density gauge long ago. I don't think I could race if you took my Boris meter away.

Thanks. Boris

 

[Andy Brown]

I have found that the Boris Gen 4 meter will take about 99.9% of the guess work out of going from site to site. I have a small weather station and a air density meter that do not even use any more.

So it must compensate for Humidity, Density-Altitude, Water temperature, Air Temperature, Fuel Temperature, anyone of which alone can effect fuel mixture burn much more than 1%.

Just asking, as I have not seen the Gen 4 system.

You are right! The GEN-4 flow meter uses current air condition. Boris

Boris,

I read over your Gen 4 material.

"[SIZE=10pt] The Flow Meter is sensitive to atmospheric pressure, air density, temperature and humidity. "[/SIZE]

How does the Gen 4 correct for humidity changes?

Thanks,

Andy

 

[bmazor]

I have found that the Boris Gen 4 meter will take about 99.9% of the guess work out of going from site to site. I have a small weather station and a air density meter that do not even use any more.

So it must compensate for Humidity, Density-Altitude, Water temperature, Air Temperature, Fuel Temperature, anyone of which alone can effect fuel mixture burn much more than 1%.

Just asking, as I have not seen the Gen 4 system.

You are right! The GEN-4 flow meter uses current air condition. Boris

Boris,

I read over your Gen 4 material.

"[SIZE=10pt] The Flow Meter is sensitive to atmospheric pressure, air density, temperature and humidity. "[/SIZE]

How does the Gen 4 correct for humidity changes?

Thanks,

Andy

All changes in air pressure, temperature, humidity, density change air viscosity and changes resistance of air flow. Just using current air condition to flow needle with the same needle setting will change the reading. In most cases adjusting needle setting to the number you already got will bring you to proper fuel flow. Boris

 

[Andy Brown]

I have found that the Boris Gen 4 meter will take about 99.9% of the guess work out of going from site to site. I have a small weather station and a air density meter that do not even use any more.

So it must compensate for Humidity, Density-Altitude, Water temperature, Air Temperature, Fuel Temperature, anyone of which alone can effect fuel mixture burn much more than 1%.

Just asking, as I have not seen the Gen 4 system.

You are right! The GEN-4 flow meter uses current air condition. Boris

Boris,

I read over your Gen 4 material.

"[SIZE=10pt] The Flow Meter is sensitive to atmospheric pressure, air density, temperature and humidity. "[/SIZE]

How does the Gen 4 correct for humidity changes?

Thanks,

Andy

All changes in air pressure, temperature, humidity, density change air viscosity and changes resistance of air flow. Just using current air condition to flow needle with the same needle setting will change the reading. In most cases adjusting needle setting to the number you already got will bring you to proper fuel flow. Boris

Ok, so Gen 4 still works on the same principle as my old school Dwyer magnehelic differential pressure gauge.

Humidity changes the pressure, but more importantly Humidity changes the burn rate of the mixture. The water content of air @ At 90 * F and 100% humidity is 2%. That amount of water in the air does a good job of trying to put the fire out. The air density can be identical, but if the amount of water in the air is different the engine will run different. If the amount of water is very different the difference in burn rate will be huge. This will require a very different mixture setting @ the same air density.

As I noted in my first post of this thread, Humidity is a bigger factor than Air density when keeping track of weather conditions over the coarse of the day at the same site.

 

[Terry Keeley]

I don't understand how ANY flow meter automatically corrects for changes in air density, can someone 'splain it to me?

 

[bmazor]

I don't understand how ANY flow meter automatically corrects for changes in air density, can someone 'splain it to me?

[SIZE=10.5pt]Not [/SIZE]ANY. [SIZE=10.5pt]I'll try to explain the main difference between (1) propane based flow meter and (2) air pump flow meter.[/SIZE]

[SIZE=10.5pt] 1. [/SIZE][SIZE=10.5pt]Propane based flow meter used canned propane flow with constant pressure and viscosity gas. So, reading depends only from [/SIZE]needle settings. The different air viscosity will need the different needle setting.

2. [SIZE=10.5pt]The air pump flow meter uses volume based pump operated by steady voltage deliver steady air flow to blow needle. Not necessary to mention --the viscosity of current air depends or air pressure, temperature, humidity, sea level. [/SIZE]

[SIZE=10.5pt]The different air viscosity changes reading with the same needle setting. Adjusting the needle to the number you already got from test run will compensate air changes. Not 100%, but real close. [/SIZE]

[SIZE=10.5pt]I'm ready to provide my flow meter to test. Boris [/SIZE]

 

[michael faszcza]

I love my boris meter. Works great

 

[bmazor]

I love my boris meter. Works great

When you got the flow meter? Boris

 

[michael faszcza]

I got it previously enjoyed last year .learned which boat likes what number and have been on on the needle ever since .i recommend this tool for any nitro racer

 

[Jim Allen]

Andy,

"Humidity changes the pressure, but more importantly Humidity changes the burn rate of the mixture. The water content of air @ At 90 * F and 100% humidity is 2%. That amount of water in the air does a good job of trying to put the fire out. The air density can be identical, but if the amount of water in the air is different the engine will run different. If the amount of water is very different the difference in burn rate will be huge. This will require a very different mixture setting @ the same air density.

As I noted in my first post of this thread, Humidity is a bigger factor than Air density when keeping track of weather conditions over the coarse of the day at the same site."

This factual statement explains the recent lack of performance encountered by some Q-40 pylon racing engines in Muncie when the weather was very hot & humid. Many competitor engines refused to pipe up, however the Nelson Q-40 engines held first place through 20 with one competitor engine at number 16. Our bench testing shows that a reduced propeller pitch, & a slightly richer needle setting helps performance. Timing changes & compression changes made the engine much more difficult to needle.

Jim Allen

 

[dwilfong]

If you think about it this way the Boris meter is checking the air not the fuel flow...........

 

[Terry Keeley]

So you're saying with a blood pressure type meter your reading is the same for the optimum needle whether you're at Denver on a 100F day or Miami on a 60F morning?

 

[bmazor]

So you're saying with a blood pressure type meter your reading is the same for the optimum needle whether your at Denver on a 100F day or Miami on a 60F morning?

This is not exactly but very close. Boris