Lehner Outrunner Motors 4140 and 7050

[RaceMechaniX]

Hey guys, At the request of a friend I put together a short video looking at the LMT 4140 and 7050 outrunner motors. Second video is of the first spin up of the 4140 on 3S. Sounds lovely.

[RaceMechaniX]

[photohoward1]

What would you use them in?

[RaceMechaniX]

The 4140 is going into my DF39 Q mono. The 7050 is waiting for a future project.

[Reesor@work]

Very cool Tyler!

[Alfa Spirit]

Choose the correct esc regarding the number of poles, that' s why outrunner motors sound incredible. Those Lehner are monsters.

[RaceMechaniX]

Some additional pics of the 4140.

Lehner 4140 pic 1.jpglehner 4140 pic 2.jpgLehner 4140 pic 3.jpgLehner 4140 pic 4.jpgLehner 4140 pic 5.jpg

[Doug Smock]

Very cool!

[meangenesracing]

My question Tyler is how much $ for these?

[Alfa Spirit]

My question Tyler is how much $ for these?

https://www.lehner-shop.com/en/outrunner/torqstar-41/torqstar-4140.html

[meangenesracing]

https://www.lehner-shop.com/en/outru...star-4140.html

Thanks for the info. I see their more expensive than the other lehner of it's size so what's the advantages

[RaceMechaniX]

The price if you purchased them from me would around $475 for a water cooled 4140 and $400 for a 4125 water cooled. For comparison a 2250 is only 10 Euros cheaper than the 4125 with similar performance and a 2280 is 12 Euros cheaper than a 4140 with similar performance. When you include a cooling sleeve for the inrunners they are basically equivalent cost.

The big difference between the inrunner and outrunner is RPM and torque. The inrunner LMT's work best at high RPM's compared to a 4-pole TP/Castle/Neu type motor. This makes them a little difficult to prop where some boat setups like larger diameters. The outrunner produces much more torque at the same amperage. The 22 series runs best at 30kRPM and above where the 41 series run below 35kRPM, ideally in the 25-30kRPM range. If you were replacing a gas or nitro motor and wanted to use your existing props the outrunners would be better replacements than an inrunner from Lehner. This is true for larger 67-101 size nitro and gas size hulls.

Q-mono's are probably the tipping point where outrunners make sense. For smaller P boats where we run 40-50mm props inrunners still make sense. The outrunners will really shine in big hulls like gas mono's, sport hydro's maybe even riggers. They match the torque of a gas motor making it easier to use common props and hull setups.

[RaceMechaniX]

Big inrunners like the TP56 series would be good equivalents to the 41 series outrunners. The 70 series outrunners are in a league of their own.

[EddieM41]

How much for the 70 series? Dimensions? The 4140 sounds like a better choice for a 51" mono. Run some bigger props. Looks like you would need a special motor mount for the water inlets? Any certain esc that is needed? Would this be a better choice than the 3080 or 30100 series for efficiency and torque?

Sorry for all the questions!

Thanks, Eddie

[RaceMechaniX]

Eddie, the 70 series will cost between $975 for the 7025 up to $1200 for the 7050.

The 4140 would be a good choice for a Rio mono as a sport/offshore setup. The 4125 can output a max power of 6kW@35kRPM and the 4140 can output a max of 10kW@35kRPM. Assuming you run at reduced speeds to spin a gas prop you will be around 6kW so comparable with a mod 26cc Zenoah. The 3080 and 30100 are higher power motors and can also spin big gas props but are not quite as efficient if you run around 20kRPM and below. A 3080 will run around $715 for the high amp fanned version and a 30100 LK Hi-Amp will run $775.

You can find dimensions of the 70 series by clicking on the specific motor. https://www.lehner-shop.com/en/outrunner/torqstar-70/

If you want raw power and have a 300+ amp controller the 3080 and 30100 are the go to solution. If you want something to run competitive gas speeds with a 150A HV speeds I would go with the 4140. I am recommending the Castle XLX2 for any motor 8S and below. For 10S and above it depends a lot of the setup and your budget. ESC's jump up in price and features.

The outrunners do require a special mount to accommodate the water inlets, but it's not difficult to mod. I 3D printed a test mount which has a widened opening for the fittings. This gives a good idea of what modding looks like.

3453847_7037_a2e4b2175ba133b87ff6e636e4063b04_1200x1200.jpg3453849_7037_246bdde840ecb9a080a14d9788d84666_1200x1200.jpg