P-Limited Motors - Im going to jump on the hot seat.

[Darin Jordan]

Well, bottom line: I'll have all the FACTS, shortly... We'll go from there.

[properchopper]

While size (rotor diameter & length) is important, a seriously not to be overlooked determinant of output strength is the gaussian flux density of the
rotor magnets. Since samarium cobalt and other rare earth metals are getting scarce [and said scarcity driving up the cost of the raw material and believe it or not Tesla is a major consumer in this equation], design engineers must determine during the pre-production stage just what combination of component dimension andmaterial raw cost will be introduced into the final design. Most all products are built to a target raw cost which determines the cost of individual components, among other things, obviously. This final raw cost, once all the other costs are added in e.g marketing, warranty escrow holdback and such, sets the final selling price. In most cases, this normally works in reverse : A product is conceived to hit the market at a predetermined price point and then the design is built up to culminate cost-of-manufacture-wise to the target market price.
One motor under discussion here has, once the producer left his association with another motor manufacturer, started a new company and set his products' target price (and resultant cost of manufacture) at an attractively accessible price point and hence required a less expensive cost of manufacture**, resulting (very likely) in less performance.

Darin's testing may back this up.

**Terry, I think you're on to something in post # 523

[RaceMechaniX]

Wow Tony, that is some deep material there. However, we are using Neodymium magnets in the RC motors while larger companies are using SmCo for their cheaper price and higher heat tolerance. However they have much lower flux density. China has the huge percentage of rare earth metals, so as long motors are coming from China the costs are reasonable. Also the amount of rare earth material is pretty low in our motors.

TG

[T.S.Davis]

**Terry, I think you're on to something in post # 523

Yeah, all the hand wringing over 50mm/56mm/60mm really doesn't mean a danged thing. If the can is empty there's no power. If the can is filled to capacity there is. There would be a weight difference.

I have a 2215 motor that has a bigger can than my 2217 motor. By a lot. Not sure why it was built that way. The thing is huge.

[Doby]

Well, bottom line: I'll have all the FACTS, shortly... We'll go from there.

"Facts" get in the way of snap decisions and opinions....

[rayzerdesigns]

I think we can all agree testing is needed.. And a viable replacement or just acoupleof options are needed..we need to try and work together to make thishappen.. I for onedo not want the linited classes to go away

[RandyatBBY]

I think we can all agree testing is needed.. And a viable replacement or just acoupleof options are needed..we need to try and work together to make thishappen.. I for onedo not want the linited classes to go away

I totally agree, it needs to get done It is some of my favorite racing. If I can run a H-10 again I will be happy

[rayzerdesigns]

I run h10 and s15 randy

[ray schrauwen]

I run h10 and s15 randy

Yes but, how thin is it?

[RandyatBBY]

I run h10 and s15 randy

Those are the ones for Sport Hydro and Hydro. but the last two years of motors are so inconsistent some times you have to go threw a lot of them to find one that will hold up. I did not want to waist the money finding one that will hold up. So I ran a aluminum CNC 444. It was slower that the rest of the competitors and I tried to be cleaner driver. It worked and I won one of the four classes. I also did not miss a race all year.

Yes Ray they have been thinned, which reminds me I need to work on the S15.

[rayzerdesigns]

you forget I run the 1500s

[Darin Jordan]

Let the testing begin!

First step, baseline runs with a load that pulls around 50-55Amps. 5.5x5.5 Graupner Carbon Prop.
20151128_164500.jpg

[Brushless55]

Pretty anxious to see how these pan out side by side

I recently heard about a club allowing a 4075 motor in P limited because the kv was within 10% of a 2030. Totally different animal. That's rated at 2400 watts. Think the 2030 is rated for 950 or something. Apples and cinder blocks. The 4075 motor wins of course. How could it not.

I get allowing other comparable motors at a club level but make sure they're comparable. Close at least. Or call your class something else like the Wisconsin guys did. No real confusion that way.

I was talking with someone up in the NW several weeks back, and he said any 36mm can works in P Limited up there, and thought dang !
that would be an unfair advantage running the 3674 motors

[TRUCKPULL]

I was talking with someone up in the NW several weeks back, and he said any 36mm can works in P Limited up there, and thought dang !
that would be an unfair advantage running the 3674 motors

NEU makes a 36mm motor also.

Larry

[rayzerdesigns]

The 36x74 are way more motor than a p
Limited.. I ran one in p cat at nats and won..