what prop for 6s mono

[jayt]

John is looking at a 2 lap set up not a heat racer...... yet.

When FE racers talk about 2-lap events - we usually mean 2-3 laps total, not running round and round until we have two good laps. John said 'less than two minutes', for 2 - 3 laps that's not very fast..... :blink:
He'll be a lot happier running 4S and the boat will still be very fast. I wonder who recommended that motor for him?

.

 

[Don Ferrette]

John is looking at a 2 lap set up not a heat racer...... yet.

When FE racers talk about 2-lap events - we usually mean 2-3 laps total, not running round and round until we have two good laps. John said 'less than two minutes', for 2 - 3 laps that's not very fast..... :blink:
He'll be a lot happier running 4S and the boat will still be very fast. I wonder who recommended that motor for him?.

Jay as per John's first post this is a 2 lap application as he clearly stated "What size prop do I use for a 1527 .5 y motor in a 32 inch mono for oval record trials?" And yes he knows it'll make a good 4S heat racer as well. You done stirring yet?

 

[John Finch]

Ok guys. Put away the swords. After hearing all the different opinions, and I appreciate all of them, I now know what it is to be a newby all over again. Who do I listen to? What does he mean? I wonder if that is so. I can see now what the newbys are going through in gas and nitro. Not as easy as it looks. The electric boats have a whole new approach to making power. Watch the heat! Watch the current draw! On a gas or nitro engine you can hear when it is lean. The electric looks like a.......lets try this and see how hot it gets. I feel like I am so much in the dark because you can't adjust as you run the boat. Like on my burned up castle SEC. I didn't know until I plugged it into the computer that I had drawn 280 amps. But then it was too late. So...............if I am learning correctly. I start out with a small prop. measure heat on motor, batteries, and SEC. Go larger on the prop if everything is cool. What temperature do I say STOP! Don't go larger on the prop. From what I am hearing the battery voltage determines the RPM of the motor so the prop should allow the rpm to be met without drawing too much current which we measure by the heat. Am I correct?

So two laps with this 2500kv motor is like 60 seconds of run time and bring it in to check temp? If it was a motor that drew less current i could run longer?

In Don's defense.....the motor was selected for saw passes only about 8 seconds per run. I am using this motor because I have two of them and that is the extent of my motor inventory. Probably should have started electrics with heat racing setup first.

John

 

[Tofastformellow]

propshop 4520 2blade

 

[Tofastformellow]

propshop 4217 2blade or 3blade

http://www.prop-shop.co.uk/index.php?id=25&section=store&sub_section=products&product_type=25

it all comes down to the density of your chosen packs . , if running lipo, then as the pack runs flat the ESC has to draw more amperage to make up for the loss in voltage ..

to balance the wattage equasion ...

a better question is what prop can my lipo battery handle ! lol

jase

 

[John Finch]

propshop 4217 2blade or 3blade

http://www.prop-shop...product_type=25

it all comes down to the density of your chosen packs . , if running lipo, then as the pack runs flat the ESC has to draw more amperage to make up for the loss in voltage ..

to balance the wattage equasion ...

a better question is what prop can my lipo battery handle ! lol

jase

Makes sense!

I got the prop Kent. Thanks!

 

[jayt]

I start out with a small prop. measure heat on motor, batteries, and SEC. Go larger on the prop if everything is cool. What temperature do I say STOP! Don't go larger on the prop. From what I am hearing the battery voltage determines the RPM of the motor so the prop should allow the rpm to be met without drawing too much current which we measure by the heat. Am I correct?

That is a good plan. Electric motors will draw as much current as they need to satisfy the load placed n them. So the higher the prop load, the higher the current draw. All the power in an FE boat is in the packs, so better packs mean higher performance. Too, the higher the motor rpm (same packs) the lower the current draw. Accelerating on and off adds very large current draw and can heat things up a bunch. The weak link in FE boats is usually the ESC. These are not really limited by amp draw, but by the heat buildup caused by high current. Keeping everything below 160*F should be safe, just remember that the ESC can cool off a lot between the time you stop running, untape and get the IR gun on the equipment. Bottom line, the more free-running the boat is the higher the rpm (speed), the lower the current draw, and the lower the temps.

So two laps with this 2500kv motor is like 60 seconds of run time and bring it in to check temp?

That makes a lot more sense than the 2-minute comment in the first post. From that I assumed you were going for a NAMBA oval heat record rather than a 2-lap. As you are tuning the boat don't run more than 60 seconds before bringing it in to check the temperatures. I have seen far too many racers run for 2+ minutes on an untested setup and either get stranded on the course with burned up equipment or make it to shore with a motor temp of 200F+ (ruined motor) and/or puffed cells. Once you get it dialed in you will know how long you can run without endangering your equipment.

the motor was selected for saw passes only...

That makes perfect sense, I've run that motor in SAW applications myself.

.

 

[John Finch]

Thanks for the help!

 

[Don Ferrette]

Thanks for the help!

You need to stop by sometime today and pick the loaner Schulze 40.160 ESC, bring a few crisp Benji's for a security deposit though. :lol: :lol: :lol: :lol:

 

[Chilli]

Borrowing a ESC is like borrowing someone's wife. :lol:

 

[John Finch]

I dropped the wife off as collateral and Picked up the ESC from Don. My Brother in law Jim came by with his wife and we were looking at the boat when I said. We have all the parts to try it. Lets see if the motor turns. 50/50 chance on right rotation. We installed the 6s setup because that is all I have. Chilli is sending me a 4s setup for record trials but they will be a day or two for arrival. The motor turned backwards so we swapped two leads to the motor and it worked correctly.

Then I said. We can charge these batteries in a short time and throw the boat in the water to see if it at least works with the m445 from Kent. So we did. I live on a pond so we went in the back yard and gave it a whirl. Jim had the temperature gun ready. I dropped the boat in the water and pulled the trigger. WOW! This thing accelerates like nothing I have ever had. We ran it 30 seconds and brought it in for a temp check. 97 degrees on the ESC. 95 on the batteries, and 90 on the motor. The boat handled very well but I need more lake to see what she will really do. Next weekend I will go to the big pond using the 4s setup from Chilli and we will see how it all comes together with more room and the radar gun. Thanks for all the help guys!

 

[HOTWATER]

I dropped the wife off as collateral and Picked up the ESC from Don. My Brother in law Jim came by with his wife and we were looking at the boat when I said. We have all the parts to try it. Lets see if the motor turns. 50/50 chance on right rotation. We installed the 6s setup because that is all I have. Chilli is sending me a 4s setup for record trials but they will be a day or two for arrival. The motor turned backwards so we swapped two leads to the motor and it worked correctly.

Then I said. We can charge these batteries in a short time and throw the boat in the water to see if it at least works with the m445 from Kent. So we did. I live on a pond so we went in the back yard and gave it a whirl. Jim had the temperature gun ready. I dropped the boat in the water and pulled the trigger. WOW! This thing accelerates like nothing I have ever had. We ran it 30 seconds and brought it in for a temp check. 97 degrees on the ESC. 95 on the batteries, and 90 on the motor. The boat handled very well but I need more lake to see what she will really do. Next weekend I will go to the big pond using the 4s setup from Chilli and we will see how it all comes together with more room and the radar gun. Thanks for all the help guys!

YEAH BABY!!!!! Whoo-Hoo!!! Excellent John!!!!

Nice when things come together like that...

-Kent

 

[Ray Sametz]

I dropped the wife off as collateral and Picked up the ESC from Don. My Brother in law Jim came by with his wife and we were looking at the boat when I said. We have all the parts to try it. Lets see if the motor turns. 50/50 chance on right rotation. We installed the 6s setup because that is all I have. Chilli is sending me a 4s setup for record trials but they will be a day or two for arrival. The motor turned backwards so we swapped two leads to the motor and it worked correctly.

Then I said. We can charge these batteries in a short time and throw the boat in the water to see if it at least works with the m445 from Kent. So we did. I live on a pond so we went in the back yard and gave it a whirl. Jim had the temperature gun ready. I dropped the boat in the water and pulled the trigger. WOW! This thing accelerates like nothing I have ever had. We ran it 30 seconds and brought it in for a temp check. 97 degrees on the ESC. 95 on the batteries, and 90 on the motor. The boat handled very well but I need more lake to see what she will really do. Next weekend I will go to the big pond using the 4s setup from Chilli and we will see how it all comes together with more room and the radar gun. Thanks for all the help guys!

John, is that the "Fear this" boat from the Oct, 2000 Boat Modeler mag???? B) ....==={]

 

[John Finch]

I dropped the wife off as collateral and Picked up the ESC from Don. My Brother in law Jim came by with his wife and we were looking at the boat when I said. We have all the parts to try it. Lets see if the motor turns. 50/50 chance on right rotation. We installed the 6s setup because that is all I have. Chilli is sending me a 4s setup for record trials but they will be a day or two for arrival. The motor turned backwards so we swapped two leads to the motor and it worked correctly.

Then I said. We can charge these batteries in a short time and throw the boat in the water to see if it at least works with the m445 from Kent. So we did. I live on a pond so we went in the back yard and gave it a whirl. Jim had the temperature gun ready. I dropped the boat in the water and pulled the trigger. WOW! This thing accelerates like nothing I have ever had. We ran it 30 seconds and brought it in for a temp check. 97 degrees on the ESC. 95 on the batteries, and 90 on the motor. The boat handled very well but I need more lake to see what she will really do. Next weekend I will go to the big pond using the 4s setup from Chilli and we will see how it all comes together with more room and the radar gun. Thanks for all the help guys!

John, is that the "Fear this" boat from the Oct, 2000 Boat Modeler mag???? B) ....==={]

Yes. It is the original wild thing named after my wife. She makes my heart sing......wild thing! It has been hanging up in the garage rafters for a decade. I saw some guys running them on u-tube and said. OH YA. Time to bring the wild thing back to life only this time....... ELECTRIC!!!

 

[John Finch]

Chilli,

I got the 4s packs and they are so big they won't fit in the boat. I will bring them to you at ovals. I will stick to the 6s setup and see what I can learn with that setup.

John

 

[jayt]

Keep the prop size small John. Your loaded rpm will be in the 40,000 - 43,000 rpm range pulling 250+ amps.

Depending on the 4S packs you may be able to get by with just one.

.

 

[Chilli]

I've got 2s packs I'll be bringing down (Hyperions 45C 5000's). I've also got other motor options. We can mix and match. Run P on 4s and/or Q on 5S to get the rpm's down a bit.

We'll get her done one way or another.

Also, I know it's a PITA but consider going to 8mm bullets. IMO 250 amps is too much for 6mm.

 

[HOTWATER]

I like the 2S2P idea and was also thinking 5S might work out well...good options...

 

[Chilli]

I only have two 2S packs so it would be 4s1p Kent. They should work out as long as we keep it the boat down to 2-3 laps max.

Remember what 4s2p looked like with 2s packs in my Seaducer?

 

[John Finch]

Wow you have some batteries stuffed in that boat. I think 2 of the 2s batteries would be right on for two laps.

John