Thud's Jr. Brute Racer

[etard]

Yes, I wanted to name the bike something cunning and racy, but after riding this beast, I had to go with Jr. Brute, cuz that is the best description I can give. Just watch the videos you will see what I mean. This bike is a blast to ride and the two speed gives you a rocket launch gear, with an overdrive gear that will take my 190 lbs to 40 mph quicker than any 150 cc scooter that I have ever ridden. The low bike is soo stable at any speed it makes you want to speed everywhere and race cars. Thud really hooked this whole thing up, all I had to do was add batteries when it arrived and poof, I'm out on the streets going faster than I have ever gone under electric power. My Death Race bike was good for about 32 mph, and never really worked right, the Jr Brute is bullet proof in comparison. I've been able to beat on this thing for 3 days now and the only grinding from the tranny is me failing to engage the gearshift correctly. Actually, that's my only complaint, I would setup the shifter to be in low gear and then push forward for high gear. I'm sure Thud has a remedy for this,I have just been riding it, charging batts, and riding it some more.

The next phase is to get all my batteries with the same connectors on it (in the mail as we speak) and take the Jr Brute to some local parking lots to get a feel for the handling. I highly suggest these Pirreli's, dang good tires for the price, much stiffer sidewalls than the Hookworms ( which need a very wide rim) but they are a bit harsh. Which leads me to want a full susser for everyday comfort. But, as Thud says, this thing is made for a single porpoise, to go fast in the twisties! So bring on the gassers in two weeks at Willow Springs!!

Here is a few videos I made, shows the power this thing has and the lack of skills I have at holding a mono. Enjoy
[youtube]ISLlnuFYujE[/youtube]
Yeah, I'm wearing my GF white sunglasses and I got a faux hawk. :lol:

[youtube]DxkDntb4HVE[/youtube]
Damn GoPro picks of slight wind noise when out of it's protective case

So what do you guys think? Will it win the race? I've never scraped a knee, but i might have to on this Brute. 8)

EDIT!!!!!!!!!!!!!

Videos Added:
[youtube]xiVA0wgmMV8[/youtube]
[youtube]CcKgB9vcxus[/youtube]

 

[AussieJester]

Actually, that's my only complaint, I would setup the shifter to be in low gear and then push forward for high gear. I'm sure Thud has a remedy for this,I have just been riding it, charging batts, and riding it some more.

Tiz how i set mine up, push down on lever for second, click the button drops back to first.

So what do you guys think? Will it win the race? I've never scraped a knee, but i might have to on this Brute. 8)

I think if PaulD could win the Death Race on essentially the same setup with the exception of no 2 speed which should be a HUGE advantage out of slow corners and off the start line! You will smoke the stink bikes.

Wish you well, we all excpet plethora of pictures, happy if we see no bikes in front of you for most of the race
(cept when your lapping them of course )

Take it easy ...

KiM

p.s can't belieeeeeve the state of your roads there that is shocking! OH along with the faux hawk
looks like you have some bum fluff under your bottom lip too

 

[SoSauty]

Nice vids Dave,
Power wheelies and all. Top speed 40mph is dialed in perfect for WillowSprings. Don't think we'll see 45mph speeds on their tight little Kart track. Think you can win on it, hmmm. . . yep, but you'll have to work at it. The 2 strokers have been at this game longer than we have. PaulD followed and studied the Pros before executing a pass. Get a fast start so you aren't behind novice riders with bad technique, the mid and back field are more apt to crash also. Don't get in a hurry to lead. Number 2 spot till late in the race is best.

Hope to see you on Friday afternoon to run lots of practice. Those Lipos take a while to charge, I'll be bringing the small gen again and you're welcome to plug in.

Impressed, you're not using a CA and can jump on the throttle. It's got to be a balanced motor/controller set up. When I check my CA it's amazing how amp loaded the motor gets at slow speeds, my little Astro3210 jumps to 130amps if I nail it going slow (200+amps on the motor side) but can only efficiently handle 60amp without thermal runaway. I Keep gearing it lower; need a close ratio 2 speed.

By the way, the Turnigy 80-100s have been sold out of stock and are hard to find right now. You win and those big Turnigy's will be worth a mint

Say, what controller and how's it setup What continous power level can you run

Dare you to lap me, and if you do, I dare you to lap me 2X's :wink:

(Thanks AJ, 12FET doesn't seem big, but 3077 FET's have a tough reputation :wink: )

(U.S.A. roads? It's not the America I used to know )

 

[AussieJester]

Say, what controller and how's it setup What continous power level can you run

Its a beefed up 12fet Infineon with 3077 fets running 18s LiPO ... the Turnigy is setup with internal hall sensors
Not sure of the continuous power level ?

KiM

 

[amberwolf]

N(U.S.A. roads? It's not the America I used to know )
http://i76.photobucket.com/albums/j25/SoSauty/PotHole1.jpg

Got lots of roads like that pic around here, both main and side streets. Sometimes they pour asphalt over the hole (without clearing out the dust, debris, etc, so it just comes out as a whole chunk during the summer, when it's hot enough to stick to someone's tire when they park there).

 

[etard]

p.s can't belieeeeeve the state of your roads there that is shocking! OH along with the faux hawk
looks like you have some bum fluff under your bottom lip too

Yeah, that's why everyone wants a full suspension bike over here.

Well, if I had the Micheal Douglas chin I wouldn't have to cover it up now would I ? :wink:

As Thud stated for his Death Race bike, 1st gear will probably only be used for the holeshot and is good to about 15mph, the sticky tires should allow me to stay above that for the whole race.

Will,
I do have a Watt's Up, and another power meter, but I'm not sure either will handle the voltage or amperage, so I might see if I can split the pack in half and use them both if they are rated to 75 volt. I did heat the motor up too hot to hold my hand on the other day going up a long steep hill full speed, but the controller heats only a little. Are they allowing us to run on Friday? If so, I would love to get some practice laps in. I also plan on getting an rv hookup, but if that falls through, I have a cheap genny that should do the trick. See you on the track bud. I can't wait to see how your bike runs with all the nuts and bolts tightened up.

 

[Thud]

AHHHH here it is. Hidden in the testing section LOL

Looks like your having an E-Blast there Etard! I love the the pass at 1:22 in the 2nd video, really shows the speeds your running. (& the faux hawk is killing your areo LOL)

Heres a questions:
Do you think its loud? (i can hear the chirping front brake rotor at low speeds LOL) RC porwerd bikes are defo not silent...& my crap cameras tend to amplify the noise the bike makes. Your vid seems to capture the true noise & levels of the bike & drive train.
I bet everyone is going to have purple on black splash painted bars nexrt year!

This bike has also set the new standard for powerlevel's+ durability of the bikes I have built to date. I pounded that tranny assembly last fall (that is the bike that put me into the 50mph club)

for guys looking for the specs on this thing I will list a few off the top of my head.

That frame is a Huffy walmart 24"wheeled mountain bike I origianly chopped, streached & re-set the steering angles on & re-welded every thing else for LFP to assault the death race 2 years ago. Its been one of my test mules for drive trains & motor winds for the last year. You can see its birth some where burried in the "before & after" thread in th ephoto's section.

Motor: An 80/100 wound 6turns 14g double in wye. aprox 100kv (motor nerds know what that means)
hall sensored with honewell s411a's, placed in the "center" of the "starts" on all 3 phases.

Controller. A hand build xiechang 12fet with irfb3077 fets. the throttle cutout circute is modified with a 1k resistor accross the c20 capacitor. NO solder on the shunt....I wish I had put bigger wires on the power & phase outputs now that i know it runs so well.

Programing: Its running with a 55amp limit on the battery input, HOT off the charger we are developing a measly 4kw of power to the motor....estimated motor efficancy at 80-85% couldn't beguin to calculate the controlers efficancy's. but "real world" estimations are less than 5 HP continuous input rating.

The thing the Gas buring guys (which I still am I remind ya'll) can't seem to grasp is 5HP (sounds increadby weak!) & full tourque from a standstill that barley tapers off at full speed, delivers amazing performance compared toa 9hp gasoline engine that only delivers its peak HP & tourque in a narrow rpm range...wihtout a 5-speed transmision no 10hp 2 stroke will match a 5 hp ellectric in stop & go performance.

Roads? I would pay taxes to have roads so nice....wait a second! I already pay & WISH my roads were so nice.
Now don't wear it out befor the big event.

Do we need to send out word & get a few more batteries in your hands for the event? I also have a butt load of Endless sphere stickers from Spinningmagnets I need to foward you. (need to represent the sphere!)
have fun & be careful for crying out loud!
T

 

[knoxie]

Hey Man that thing is sick, I couldnt figure out why the controller hadnt smoked :? and was beginning to think you must have a new RC controller of some kind in there? and then I read further down Thud has modified it, seems its the best way to get reliability from these RC setups then guys? or have I missed a meeting :wink: very quick bike there etard and you can ride too I think you are going to be in with a very good chance in the race 8)

I love the stretched BMX look too, one thing Thud how come you didnt run sensored controllers for the death race? coz the HVs both of them fried in some style didnt they? was it just a pure power decision? I suppose race bikes will always be on their limit as far as reliability goes.

These couple of vids are a very strong advert for RC bikes IMHO nice job from the both of you, get some sensors in the cans get the reliability up and you have yourselfs a winner, cant wait for the race 8)

 

[Thud]

Knoxie,
I can only wish I had the controller issues solved before the Touscon race
If you look closly that controller has an anodised case to match the Bully's color scheme. For some stupid reason I had my brain totaly stuck in that "external" hall sensors would work for these big motors.
If burtie had politly said: Thud, you stupid tit! Put halls inside your motor & report back soon! We would have been untouchable in Tuscon. (at least thats what i say .LOL)

Part of the "secret sauce" for these set ups is the re-winding & termination of these motors. De-tuning a slight bit actually. Once we make the motor a little easyer on the controller we can tweek the controler's to get what you see in Etards video

I am really curious to get testing with Burties TA unit & see if we can streatch the performance/reliability envelope to the next notch on the belt.

This is what RC (HOBO FTW!) e-biking is all about.

 

[knoxie]

Hi Thud

Thanks for clearing that up! yes man that is a special thing then, the only thing that has put me off thus far is the reliability factor, Pauls race antics were awesome to watch, I think Etard will also bring home the goods, get some good elbow pads and a helmet though!!

I think the next death race the top 2 bikes will be electric then if they let you all run in the same class?

Thanks for sharing the video Etard looking forward to more from you 8)

 

[nicobie]

Nice bike! Looks like Thud has taken it up a notch or two since the DR. There is a chance that I'll make to Willow Springs, if so, I'll see you there. I bet you do good.

 

[newb]

I highly suggest these Pirreli's

I would really appreciate knowing what rim you are using?

Best of luck at W.S.

 

[Thud]

rims= Alex DM24

Item Specifications
Color Silver
Weight 395g
Width 32.2mm
Intended Use BMX
Hub Drilling 36spokes
Rim Depth 17.2mm
Brake Compatibility Rim Brake
ERD 395mm
Valve Schrader
ISO Diameter 406 / 20" BMX
Valve Length Schrader
Wheel Size 20"
Tire Type Clincher
Rim Center Offset 0mm
Material Alloy
Rim Joint Pinned/Sleeved
Brake Track Non-Machined

 

[StudEbiker]

AWESOME! 8)

 

[newb]

rims= Alex DM24

Cheers Thud, thats what i was hoping they were.

Much Appreciated

Brilliant Job btw

 

[etard]

Update Update Update

New vids added to the first post as well as this one. Yes, I did a Thud and lowsided the bike applying too much power on the edge of traction in a right hand turn, the bike is soo low that I don't think I even let go of the handlebar, I was only like a foot off the ground already! :lol: I think my avg. corner speed was 22-25 mph, so first gear wasn't even an option. The way this bike is setup it maxes out at 40 mph pretty quick and 1st gear is only good to about 15 mph so I'll prolly only use it for starting line antics and showing off for teenage runaways on a bad trip. :wink: Watch the second video and you will know WTH I'm talking about.
[youtube]xiVA0wgmMV8[/youtube]

[youtube]CcKgB9vcxus[/youtube]

 

[SoSauty]

Thud,

Motor: An 80/100 wound 6turns 14g double in wye. aprox 100kv (motor nerds know what that means)

Nerd?? Actually, it's closer to 102Kv

the "secret sauce" for these set ups is the re-winding & termination of these motors

Thud, please do tell; I can handle the truth! Are these Turnigys generally terminated in Delta?

Newb; keep in mind that Pirreli's are 16"moped tires that somehow fit wide 20" bmx rims.

ToyRacer is running rather spiffy, wind seems to really blow over at Willow Springs, gotta love a challenge
Etard, I'm hoping we can slip onto the track a wee bit Friday, nothing wrong with an 8am Sat run, have insurance waivers signed and all that. Can you believe it, a nice racing layout right at our backdoors You go team Thud.

 

[newb]

Newb; keep in mind that Pirreli's are 16"moped tires that somehow fit wide 20" bmx rims.

Ya, Im familiar but thanks for looking out. Just wasn't sure if i could use the DM24 vs DX32 @ 2x the price. If those 2.5's fit that rim so well then I should be able to fit one of these 3.0's on it for my Cannondale Gemini DH conversion.

Shinko 244

Shinko SR241

 

[etard]

Oh yeah, talking about potholes and such, I found this road sign to be quite refreshing, too bad this section was only for like a mile.

"May use full lane," and I did!

Newb,
I think the 2.5 is plenty wide enough, I'm not sure if a wider tire would fit in your dropouts. I really like that first tire though, it reminds me of the Maxxis Holy Rollers I have on my Specialized and also the sport touring tires on my GF's Yamaha enduro. I take those tires anywhere, even at 20 psi they are not too bad in the dirt and sand. People comPlain about them when I let them ride either on the trails but I think they make you a better rider, and they are also good on the street.

 

[newb]

As bad as those roads are riding a hardtail must be painful?!? Considered a Thudbuster?

Newb,I think the 2.5 is plenty wide enough, I'm not sure if a wider tire would fit in your dropouts. I really like that first tire though, it reminds me of the Maxxis Holy Rollers I have on my Specialized and also the sport touring tires on my GF's Yamaha enduro. I take those tires anywhere, even at 20 psi they are not too bad in the dirt and sand. People comPlain about them when I let them ride either on the trails but I think they make you a better rider, and they are also good on the street.

My plan was to use the Pirelli's as well but i went for a ride this wkend that showed me i need a bit more aggressive tread design. Both those tires are classified as a 80/20 on/off road use. I too prefer the 244 and they're only $23 ea. (same as the ML75's), plus some great reviews. As far as the drop outs are concerned, i know the back will fit and the front may need to shave an 1/8" off each side but with the narrow rims i'm hoping it'll squeak in.

 

[Thud]

SoSauty:
I have yet to find a turnigy or axi motor shipped from the factory in any other termination than Delta.

(& thanks for the correction! I would hate to have any inaccurate information on the world wide web! :lol: )

Newb: the issue is more the chain stay widths. they tend to get tight on the wider wheels. If your running V-brakes they also can pose some problems. lots of bmxers use a smaller version...Disc brakes solve the problem but then you are back to drop out spacing as most disc hubs will need 135mm.
STOP-CHOP-& ROLL!

Etard:
My lowside slid a lot further! cmon' maann! Get foward keep you eyes on the line your carving & lead with the shoulders baby! Go! GO! GO!GO!

I thought that chick was going to steal the camera.
do you have enough batteries for 2 running packs? (bare min. IMO)
Keep having fun!
(REMEMBER! A lot of guys go to extreams to mimic a "rat ride". That "Michigan Patina" (AKA-Rust) on the cranks would cost a ton to replicate!!)

 

[SoSauty]

Etard,

I have 2 (6S) 6000mA nano lipo bricks to loan 'ya, just gotta get 7 more. Plan to use 'em for wife's 22.2V baby bafang afterwards. I'm sure you'll give 'em a good break in :wink:

(Off topic: Excited to learn they terminate in Delta, wondered why such hi Kv for Turnigys. Got a baby Turnigy63-70 backordered and hope to squeak 3 K continous out of it, rewind 7T double, hollow axle, 10S & Canstle HV80 for current limiting)

Don't know if I'll have my purple splashed black handlebars installed by Willow Springs race LOL.

Question; will we someday have an affection for that e-bike whrrrrr noise made when the green flag drops, kinda like the affection I have now when I smell 2 strokers right after that giant bee hive sound at the start of a race; or will be like trying to replace the campfire with a coleman latern

 

[katou]

Thud, congrats! RC that doesn't explode!!

What is it about this setup that makes it so tough?

Katou

 

[liveforphysics]

Thud, congrats! RC that doesn't explode!!

What is it about this setup that makes it so tough?

Katou

It doesn't use an RC controller. That's always been the weak link.





I gotta say, I saw the man pin the throttle and not instantly see a view of blue sky followed by sliding and cartwheeling.
Pink bike doesn't play that. Neither does the planned build for this race.

 

[Thud]

katou asked:

What is it about this setup that makes it so tough?

Realistic application of know limitations....
#1 Re-wind a motor for the absolute minimum required expectations.
Here is the dope:
parameters----------Stock-------rewind
coper cross section--18.9--------25.0 (24% more copper=more tourque potential)
R (mohms)------------30.1-------13.5 (reduced the potential resistance of the motor by more than 1/2)
Delta R ---------------20.1--------9.0 ( terminated delta, this would be a controller devouring MONSTER)
WYE R-----------------60.2-------27.0 ( terminated like this we have raised the resitance over the stock "delta"
termination by 26% & elliminated re-circulating currents)
COPPER GRAMS-----254.5------357.7 (increased the overall weight by 29%...we lost 4% of the copper increas to the"ends" of the winds)

#2-We have a functional current limiting controller, not "over modified" to deliver more energy than the FET's can sustain. (this means I have finaly learned enough to not be so dangerouse to ellectronics )
We must recognise that these high rpm motors are a totaly different animal to controll over the Hub motors the designers had in mind.

You can pump a ton of current into a hub motor & the controllers survive (for a short while anyway) & the motor itself is a limiting function. The Low resitance Outrunners & Astros will accept all these things will deliver & beg for more. making the controller the weakest link. Right now, if I trust the parameter designer, its looking like 4.5kw is what a 12fet with 3077's will accept without getting into thermal issues. (its more a function of the modded throttle cut out circut, any more & it starts to get very fussy....which is prolly a good thing)

If I could find My brand new CA it would be installed & start building some history....but I fear it was in a box that got thrown away inadvertantly.


Luke said:

Pink bike doesn't play that. Neither does the planned build for this race.

HAha! Hope you have your "planned build" started soon....I won't be there to help you get it finished!
Talk is cheap buddie & this is a "Road Race", not an episode of "Jack-Ass"
How do you like your "Crow"?