lol. Tell her I'm sorry. But this IS R/C after all! :) When my wife gives me grief, I just say "Would you rather me go the to bars doing God-knows-what, or be interested in something harmless like my R/C toys?". And you can always tell the missus that this purchase can be your early b-day or Christmas present. :)

The hi-amp simply has direct connections from the coils to the output wires so has less losses. However, the non-hiamp version does give you the flexibility to reconfigure the motor from D to Y for different kv ratings. I guess it depends if you'd rather have minimum resistance loss or more flexibility...

Oh, and the hi-amp doesn't necessarily mean it will pull more amps, it just means it can handle higher current since there is less resistance due to the coil configuration feature.

Oh, Ok. So does the KV rating go up or down when you change the wires?

I believe it comes wired in D config. So wiring it in Y config decreases the kv by a factor of 1.73 IIRC. This would of course mean you can run higher voltage for the same total rpm.

Awesome. Thanks for all the info. Time to go to the "store". :027:

Yep.. the truck should be right at 11lbs with a pair of 4s 5000 packs (4s 10000mah total)...

I think I'm going to tear down my 12000packs and make it a 800omah... I just don't need the enormous runtime and I would like to shed a few lbs.

I hate to take apart a perfectly good pack... but that's the plan right now.

I don't know much about the Lehners... never even seen one in person. But I'm sure a 1940 can do the job pretty well....

Hey, what's up GD?! Thanks for the info. I think I'm actually going to run a single 4s pack now. Maybe the 6000HV or 8000HV MaxAmps?

Dang it!! I just tried to order the 1940/9 and it's out of stock!! The only one available is the 1940/10 hi-amp. I really don't want the hi-amp. Crap!

Oh, I forgot something :mad:1 :035: :013: :019: :031: :026: :028: :007:

It's done!! I went ahead and got the 1940/10 hi-amp. I actually like that selection and think it will work really well. I sent Mike a note and asked him to make me a motor mount too. Hope he comes through on it for me. I'm getting stoked now!!:027:

Cool. I think you'll be happy. What voltage do you plan to run on that? With a kv of 1568, you should have plenty of voltage options.

Exactly. Right now I'll be running it with 14.8 since I'll be using the Mamba Max esc. When the MMM comes out, I'll go to a 5s or 6s. Or more . . . ? Either way, I figured this motor would handle all those options well. With the lighter batteries than GD ran and smaller 1940 motor, I think I'll be about 11 pounds or just under. I think I'm going to be real happy!

Oh, hey BrianG . . . on your motor info you have the 1940 as having a 3.175" shaft when it actually has a 4mm. Unless I read it wrong. FYI.

Yeah, I've been meaning to update that. I'll do it now. I actually got that info from the lehner site. I guess there must be different shaft options?

EDIT: Updated the 1940's with a 4mm shaft...

Yeah, it caught me off guard since the 1950 was a 4mm. Oh well, Mike straightened me out. :005:

Seriously, your motor calculations and everything is awesome - an excellent resource. Thanks.

Np. :)

Me thnks a 6s 5000mah maxamps pack would make this truck FLY!!!!! heehee

The 1950 is 5mm. 1940 is 4mm, as well as the other 19 series motors (4mm).


Brain, for the Wye vs Delta configuration, I'm not exactly sure which, but one of them increases the KV by 1.73, not decreases. I just don't know which way does what lol...

Nevermind...Wye decreases KV (by reducing voltage by 1.73). When the motor is used as an alternator, Wye boosts voltage by 1.73, while current is reduced by 1.73. So in a motor configuration, its logical that voltage is reduced by 1.73. So I guess this means using wye allows the use of more voltage, since KV will end up being the same...

This is pretty useful.

it depends BP..

A Delta turns 1.73 times quicker per volt than a Wye.

So going from Delta to Wye will decrease the RPM with 1.73 and will increase the torque with 1.73.

Going from Wye to Delta will increase the RPM with 1.73 and decrease the torque with 1.73.

A lehner motor comes as a Delta, and can be configered as a star, resulting in a 1.73 lower KV.

It is easy to see which is which by looking at a coil diagram. In a D config, voltage is applied across one coil. When in Y config, voltage is applied across 2 coils (but as a vector, which is why it is 1.73x, not 2x). So, in effect, Y config has more turns so kv decreases.

yes, and this would explain the dividing thing; that 1.73 is the result of square root 3.. Get it?

Well, I just ordered the rest of the supplies. Carbon fiber angles for the battery tray, Mamba Max ESC, Hyperion 4s 4350 lipo, BEC . . . I think that's it. Already have the radio. I'll start posting pics as it comes together. I asked Mike to make a motor mount for me a couple times - no response. Oh well, I guess I'll just have to make one myself. Does anyone have a spare motor mount for the CRT? :027:

Latest Update
 

Ok guys, I'm close to completion. I'm still waiting for my carbon fiber angles to make my battery tray, and I'll clean up a couple other things . . . but it's driveable. I took it out last night in the street and it's sick! It surpasses my expectations. I just wanted to thank everyone here for their help. Serum, GD, BrianG, BP, Jolly, Squee, Mike, and of course thanks to the academy.

Seriously though, thanks everyone. I'm stoked. Check out the photos of the temporary setup. Please keep in mind that the batery will not be held in place by the hairline ziptie shown in the pics. I hope that CF gets here today.

Oh, for any of you wondering, here's what I have in it:

Lehner 1940/10 Hi-amp with Kyosho 44t spur and 15t pinion
Hyperion 4s 4350 li-po
Airtronics 94359 (this thing is sick on 6v!!!)
Dimension Engineering 6v BEC (look closely and you'll see it by the motor - tiny!)
Mamba Max ESC
Spektrum SR3000
And of course, it's a Jammin CRT Pro chassis

I guess now that I look at the photos - you can't see the BEC :005:

Well, it's small and works awesome. Here's a link for anyone that wants more info on it:

http://www.dimensionengineering.com/SportBEC.htm

Here's some close ups of the ESC and BEC. I will mount the ESC to CF when it arrives, and make a CF cradle for the back of the Lehner too.

sower, looking good n tasty. what diff fluid weights are you using? thx

Hey, what's up Cadima? Thanks, but it's pretty sloppy right now. I just had to throw something together to run it. I finally got my carbon fiber angle in so I'll be making my battery tray, and I just got some more aluminum so I can make a new motor mount. Now I just have to find the time to do it :002:

Anyway, the diffs have 3k in the rear, 30k in the center, and 7k in the front. I've taken it to the track and it rips. It's awesome. There's just something really cool about people's jaws dropping from a silly fast & silent CRT. :005: It's getting a little hot with my 15t pinion though. I will be dropping down to a 13t this next week, and hopefully that will take care of it.

How's yours coming? I liked the last battery mount idea (hinge and single pin). Is that what you're going to do for sure?

Mine's not coming. Took a more than a full month to get my chassis material from onlinemetals. Hate those guys. Gonna cut it this week. once I have the chassis, it's on. I've got my sights set on the battery mount idea. But it'll be the last thing I work on probably.

Hey Sower,

You have got a hell of a CRT. Very nice indeed. What kind of run times are you getting with that battery, and with what style of driving? (racing, speed passes, bashing, etc)

Thanks

Hey, thanks! It's still in progress, but driveable. I still haven't run a full charge out yet, so I'm not sure. Last time out I had about 25 or 30 minutes of pretty hard race driving and didn't run out. I'll let you know when I get it dialed in. I want to weigh it too. I'm very happy with it so far.

Bummer - sorry to hear that. Well, hopefully it will be up and running soon. Can't wait to see it!