|
Slash 4x4 Buggy 1717 6s
Hi, wanted to show you guys my Slash 4x4 Buggy conversion with a Castle 1717 on 6s.
It is basically finished now but I still need to find a good suspension setup. - LCG Chassis dyed black - Removed anodizing on colored parts - Stock A-Arms with XO-1 hub carriers etc. - Stampede front bumper - selfmade front wing - selfmade center shaft from 10mm CFK tube, 10% lighter than stock - Stampede wheeliebar with alloy/rubber wheels - Diffs and CVDs from XO-1 - RR Gen3 Slipper for Revo 3.3 38t - selfmade motor plate - selfmade "braceplate" which bolts the complete backend together - selfmade CFK chassis brace - TT ST-1 spoiler mount modified - Stormracer spoiler (small and light) - XO-1 wheels belted - GRP 1/8 GT wheels belted - VP Pro Buggy wheels belted - Castle 1717 1650KV from XO-1 - Mamba Monster Extreme - Traxxas TQI - TT MT4 G3 stock Servo Gearing with XO-1 tires: 22 pinion 38 spur, should give 95mph theoretically. Gearing with GRP tires: 26 pinion 38 spur, should give 100mph theoretically. Weight with XO-1 tires: 3.85kg ready to run with 5000mAh 6s 40C lipo. Weight with GRP tires: 3.72kg ready to run with 5000mAh 6s 40C lipo. Topspeed so far with GRP tires and 100mph gearing: 142kph or 88mph Topspeed so far with XO-1 tires and 112mph gearing: 149kph or 93mph Video: http://youtu.be/GS3Os0yg6XA http://i54.photobucket.com/albums/g1...ps9df7c77b.jpg http://i54.photobucket.com/albums/g1...ps0e2e8f66.jpg (click to enlarge) http://i54.photobucket.com/albums/g1...ps4e8e3a73.jpghttp://i54.photobucket.com/albums/g1...psc1a134e9.jpghttp://i54.photobucket.com/albums/g1...psf971ca06.jpghttp://i54.photobucket.com/albums/g1...ps912a5050.jpghttp://i54.photobucket.com/albums/g1...ps7d9fe89d.jpghttp://i54.photobucket.com/albums/g1...ps039f2811.jpghttp://i54.photobucket.com/albums/g1...ps6dd9040d.jpghttp://i54.photobucket.com/albums/g1...ps5e88716a.jpg |
I think I would remove the front bumper in exchange for a longer scoop - the scoop pushes the front down while the bumper pushes it back up. Cool slash for sure - there is a 120mph+ slash 4x4 in Detroit running 6s on a 2200 motor IIRC. Capable platform for sure.
|
Monster Mike: Yeah, it could use a little more downforce in the front, I will change that.
Got a Mobius action cam, really nice camera. Good quality, but small and not expensive. Here is a on-board clip (watch to the end :mdr:) http://youtu.be/0Df_XganRlU |
Little update:
The selfmade CFK centershaft did not hold up, it broke. Strange thing is, that it happened during normal driving, no crash or something. Have replaced it now with a stock centershaft, seems to hold up now with the chassis brace. Then I made a new front wing from an 1/8th buggy wing and removed the Stampede Bumper. Doesn't look too good IMHO, but I think it makes more downforce. Apart from that no defects or issues or crashes, it just runs. What I really like about the Slash drivetrain is that there are no drivecups (like on 1/8th scale buggys) that tend to wear down and are pricey and work intensive when they need replacement. Only part that wears down is the centershaft, but that is cheap and easy to replace. Also found the reason for the bad straight line stability, it was the old servo I took from a TT MT4G3 which didn't center precisely anymore. Replaced it with a TT DS1015, much better now. Also experimented with toe-in on the frontwheels, which worsened steering so now I'm back to 0 degrees. Maybe I'll try a little toe-out sometime to see what happens then. Mounted a sway bar kit, seems to make a difference, the car rolls less now, but I guess I need some thicker wire to accomodate for the increased weight in comparison to a stock Slash. The GRP S3 tires make nice traction but don't last too long, after about 10 packs they were almost done. But I must say I let the tires spin a lot. Funny detail: Found two dead flies inside the rims, seems like they have been sucked-in somehow. Body is now airtight from the underside, made some foam-thingies out of a touring-car bumper and also put some foam to the sides of the chassis to seal everything. Put the mobius cam on the rear shocktower, but didn't turn out good, videos are too shakey, need to mount it firmer somehow. As I am getting more practice, I begin to feel really safe while driving it, I can make 20 80+ mph passes in a row without breaking a sweat, in my opinion it is superior to the XO-1 in any way apart from looks. Better acceleration, better braking, and the most important thing, it's actually driveable and controllable on non-perfect roads. Even when it looses traction it's still controllable. And I can go through a full pack without heat issues. The braking distance is really short, under 100feet from 90mph. RTR weight with GRP tires as on the photos (but without cam) is 3572g now. http://i54.photobucket.com/albums/g1...ps614c3ddd.jpghttp://i54.photobucket.com/albums/g1...ps766d9846.jpghttp://i54.photobucket.com/albums/g1...psb751407e.jpghttp://i54.photobucket.com/albums/g1...ps43b87997.jpghttp://i54.photobucket.com/albums/g1...psf62f8e50.jpghttp://i54.photobucket.com/albums/g1...ps307e314d.jpghttp://i54.photobucket.com/albums/g1...psc80c7b99.jpghttp://i54.photobucket.com/albums/g1...ps99244a57.jpghttp://i54.photobucket.com/albums/g1...psbee045a0.jpghttp://i54.photobucket.com/albums/g1...psc6675c28.jpg |
Looking good. Tires are just like you describe - the better traction they provide, the faster they wear out. Regarding front toe - zero degrees is pretty ideal. Generally speaking, toe-in generates better initial steering off power, but tends to push more coming out of the turn(on power). Toe-out is essentially the opposite, providing less initial steering entering off power, but much better steering on power. Of course many other things in the setup affect steering.
Rear toe-out is almost unheard of, as it generally created instability. Rear toe does create some scrub, but adds straight line stability(pretty important for high speed). If the rest of the setup is pretty rigid(minimal flex and play in the linkage, etc.), I like 1-2 degrees rear toe for high speed straight line work(3 degrees is the norm for off-road). |
Definitely must be a capable platform.
Some serious power you have there on your Slash. I'm amazed. |
Little update:
As it turned out, the earlier 93mph run with the XO-1 tires (geared to 112mph with 26/38) was not valid, seems like the tool I used calculated the values on it's own based on the location and timestamps and did not use the speedstamps. Made a new measurement, this time with the GRP tires (100mph theoretically with 26/38) and reached 94mph. The XO-1 needs a 121mph gearing to reach 100mph, which means, the Motor is less loaded in the Slash. Would be interesting to see what speeds the Slash can go to with 121mph gearing, I would guess something between 105 and 110mph. Also made some acceleration tests, it accelerates from zero to 90mph in about 4 seconds and needs about 300ft of space to do this :mdr: Now I'm thinking about putting something bigger in. What do you guys think, would a TP Power or Leopard 58x82 1420KV motor on 7s work with an XL2? Topspeed 151kph / 94mph http://i54.photobucket.com/albums/g1...psc720a4cd.jpg Acceleration to 146kph / 90mph in 4 seconds: http://i54.photobucket.com/albums/g1...ps38be4aaa.jpg Quote:
On the rear I have 3.5 degrees toe-in if I remember correctly, but I think the rear hub carriers can be swapped around to get 1.5 degrees, will try that sometime. There is still play in the linkage and in the wheel carriers, need to find a way to reduce that. Dafni: Thanks, I'm amazed too how well this thing turned out :) |
Little update.
Got a GPS speedometer and a sports radar for speed measurement so that I don't need to strap my phone to it anymore. Mounted the cam on the rear shocktower and the speedo on the front shocktower so that it is visible in the video. Problem with the shocktower mount position is that it is very shaky, need to find a way to dampen it somehow. Also found a closed road for driving without cars or people around. Very nice. What was not nice that I almost hit a rabbit that decided to cross the road just in front of my car. That would have been quite a mess :) Then I crashed for the first time, wanted to chase my buddys 1:1 car and didn't realize he was braking, thought he would go WOT down the road, but he didn't :( Car went under his car and then my right rear tire got overrun by his rear tire. Well, his tire won. Fronstpoiler mount broken, speedometer broken, cam broken, bulkhead broken, rear axle carrier bent, rear wheel broken, shock-cap ripped off. For being run over by a 1:1 scale car not too bad. What really sucks is that the cam and the speedometer broke. Searched for the SDCard from the camera for half an hour and eventually found it, but unfortunately the video didn't get saved anymore, so no footage of the crash. Repaired the car and added aluminium shock caps and camber links. Also dyed the shocks and springs black, now they don't look like cheap RTR shocks anymore :) Changed shock oil to 60 front / 50 rear, now it needs some testing if that is better than the 70/60 before. Checked the front diff ring and pinion gear and inspected the driveshafts. Looks good, almost no wear on the front diff and the driveshafts look like brand new. The rubber boots with grease inside seem to do their job. All 8 wheel bearings needed replacement, they were not running smooth anymore and two were really hard to turn. Also received some 32 shore Johns BSR Buggy Dirt Oval Foam tires and an STRC alloy steering but haven't tried them yet. The BSR tires look like quality tires. Hope I made the right choice with the 32 hardness. Weight of the BSR tires is exactly the same as the GRP 1/8 GT tires, 350g for the complete set. Diameter is 105mm. http://i54.photobucket.com/albums/g1...ps25f1f987.jpghttp://i54.photobucket.com/albums/g1...ps59b66b5a.jpghttp://i54.photobucket.com/albums/g1...ps402f3766.jpghttp://i54.photobucket.com/albums/g1...psd8d809d6.jpghttp://i54.photobucket.com/albums/g1...psfeca61e1.jpghttp://i54.photobucket.com/albums/g1...ps0362458e.jpghttp://i54.photobucket.com/albums/g1...pse54a685d.jpghttp://i54.photobucket.com/albums/g1...ps86a16373.jpghttp://i54.photobucket.com/albums/g1...psee222dd2.jpghttp://i54.photobucket.com/albums/g1...ps0ea90e27.jpg |
My experience is that full size cars pretty much always win when matched in a crash to an RC car(particularly 1/10 size)! Really though...not a bad result considering the potential carnage.
|
A few more changes to the car.
replaced the wheeliebar made from a Stampede bumper with one made from an XO-1 diffusor. The wheels are more to the back, wider and lower to make sure unintended wheelies at high speed don't end in a flip over. Since I needed the rear wingmount for my twin truggy again and wrenching wasn't too convenient with that thing in the way, I decided to make my own wingmount that is attached directly to the top of the shocktower. It looks a little "Low-Tech", but works well and is very light compared to the classic buggy wing mount. Car weighs 3554g now ready to run with GRP tires. Then finally had the opportunity to run it again. The Shock setup with 60 wt front and 50 wt rear seems to be better than the 70/60 before. Although I have the feeling, that when almost fully compressed, the oil is too light. Maybe I should try some linear rate springs. Also tried the 32 shore BSR tires. Well, they did not make very much grip and generally seem a little too hard, i.e. they don't "soak up" little bumps in the roads, I could hear the motor spin up briefly sometimes. Did not dare to go topspeed, as the rear of the car would get squirrelly when trying to accelerate hard. Tires didn't warm up after some time like the GRPs do. Made a burnout until they started smelling and were really hot, but this made almost no difference in grip, just a tad better. I guess I have to try 25 or 30 shore, but not sure if I will do this since the GRPs are much cheaper and perform well for me. Also I am not sure, if the BSR like the camber change when the suspension is compressed, as they are completely flat. What was funny though, that I could make 30 foot long lines on the asphalt with them :) Apart from that, they seem to be quality tires, no chunks ripped out or something like that, held up perfectly. http://i54.photobucket.com/albums/g1...ps51d6bae6.jpghttp://i54.photobucket.com/albums/g1...psa49f8cfe.jpghttp://i54.photobucket.com/albums/g1...ps302c9dc4.jpghttp://i54.photobucket.com/albums/g1...pscf618f4b.jpghttp://i54.photobucket.com/albums/g1...psee5cec3e.jpg http://i54.photobucket.com/albums/g1...ps12657a07.jpghttp://i54.photobucket.com/albums/g1...ps25229f0c.jpghttp://i54.photobucket.com/albums/g1...pse6e009e1.jpghttp://i54.photobucket.com/albums/g1...ps8c641b80.jpghttp://i54.photobucket.com/albums/g1...psd8a14c16.jpg |
That is great to see some doing the speed stuff Lizard.
Hello everyone I poked my head in for a few. I try to follow up on this a little more. Looks good to me so far. :D |
Thanks. Will keep you guys updated.
It might take some time, but it will receive a motor upgrade in the future :happy: |
The xl2 will definitely run the bigger motor you suggested.
Changing the rear toe in from 3.5 to 1.5 will free up a few miles per hour. Have you pulled a data chart to see how many watts you are pulling at top speed? I imagine a CC 2200 motor could get you the same speed with the added benefit of less weight and more kv. |
Will try that with the toe-in. I could just increase gearing, but this wouldn't allow for running through a full pack without heat issues anymore. I think with the 1515 this would be even worse, it's a lot smaller and lighter than the 1717.
The XL2 was my first choice also, it's reasonably priced, quite small and has a really nice set of features, especially the datalogging is very nice. But after thoroughly investigating and getting a broken one (to get an idea about mechanical/cooling design) I found some problems with it: - cogging - poor electrical design, something with the FET drivers and too long PCB connections (User "Uber" on RCGroups found out), Castle solved that by having the FET driver manufacturer make special drivers only for Castle instead of fixing the design - Castle doesn't seem to care about it, no firmware updates, no comments or mitigations on the cogging issue - poor cooling design - mechanical design unsuited for car usage with bumps, shocks, vibrations and dirt - They still seem to go up in smoke from time to time with no apparent reason and seem to be more delicate in general I have now ordered an Alienpowersystem 8S 250A sensored ESC and a TP5040L (58x82mm, 836g) 1260kv sensored motor. Don't know if that one is more reliable but it was cheaper and shouldn't have cogging issues because of the sensor. No data chart, don't have a data logger, but I have found this on another forum: I'ts a HPI Firestrom with Poseidon 1717 2200kv Castle knock-off, gearing for 155mph and same weight as my Slash. Topspeed was 123mph. 300Amps would be about 6kilowatts. Assuming 90% efficiency (probably too high ...) this would mean 600W of heat that has to be dissipated somehow. http://i1105.photobucket.com/albums/...ps8d38c932.jpg |
Made a video with lots of onboard footage, different camera angles and places.
Hope you like it :) [YOUTUBE]EVJkGJpTDKI[/YOUTUBE] http://youtu.be/EVJkGJpTDKI EDIT: fixed the embedded video link. |
The Alienpowersystem sensored motor and ESC for the next (and probably last) power-upgrade finally arrived :)
Unfortunately, the motor is not a TP5840L (57x80mm, 836g, finned can) 1260KV as ordered, but a TP5670 (55x90mm, 962g, smooth can). Bruno insisted that it's the motor I ordered and that it has 1260KV. Well, my calipers say 55x90mm, my scale says 962g and the Mamba Monster Torque Control KV-measuring says 1130KV. Now I have to re-think gearing again. But the good thing is, it seems to fit in my Slash, so atleast now I don't have that "maybe I should've gotten the bigger motor from the beginning" problem since it's already the biggest motor :) Motor case is the new 2-Part case with only the endbell removable. The rotor is somehow scratched at the ends, I wonder if they throw all the produced rotors in a big box at the factory. Nice is, that it's balanced by drilling holes in the rotor, so no "balance putty" that might come off eventually over time. The sensors fitted by Alienpowersystem seem to be glued into the motor with epoxy or something like that. Nice is, that they are "standard" Honeywell SS411A hall-sensors that can be bought everywhere for a few bucks. ESC is an Alienpowersystem 8S 250A Gen3 sensored ESC. They seem to be based on Flier ESCs but with some changes. Ordered the ESC "naked", without shrinkwrap, cables and heatsink because originally, the cables come out of the side which wouldn't fit in the Slash. But it came with heatsink mounted. Interestingly, these ESCs seem to be made by hand, only the logicboard is probably pre-assembled because of the SMD parts on it. According to Bruno, the ESC and Motor with sensors installed have been tested and "run nice and smooth". We'll see :) From a mechanical and cooling point-of-view, the ESC seems good. The Logicboard is soldered to the larger PCB and not plugged with a connector like on Castle's XL2. Heatsink was properly mounted with thermal compound (the removable stuff, not glue). All cables connecting to the PCBs have been secured with silicone. Soldering pads for the motor and batterycables are quite large and on both sides of the PCB, 8AWG cables or even bigger ones fit without problems. The FETs are some with a quite large case, not like the SMD ones found on Castle's controllers. According to Bruno, they are "Automotive-FETs" and are supposed to be more robust somehow. But it's only 18 FETs. Mamba Monster has 36, Mamba XL2 48. Well, we'll see. Caps are 4x 35V 1200uF = 4800uF. For comparison, the XL2 has 2x 680uF and 2x 560uF = 2520uF. With CC Cap Pack (4x220uF) that would be a total of 3400uF. Seems like the caps on the APS ESC are plenty, I guess I don't need additional ones then. http://i54.photobucket.com/albums/g1...ps5e9fa852.jpghttp://i54.photobucket.com/albums/g1...ps8aa44c08.jpghttp://i54.photobucket.com/albums/g1...ps032c8e58.jpghttp://i54.photobucket.com/albums/g1...ps374f90c9.jpghttp://i54.photobucket.com/albums/g1...ps797cfe0f.jpg http://i54.photobucket.com/albums/g1...ps8eedd3e4.jpghttp://i54.photobucket.com/albums/g1...psd2aa0f70.jpghttp://i54.photobucket.com/albums/g1...ps8269073e.jpghttp://i54.photobucket.com/albums/g1...ps7ac2443e.jpghttp://i54.photobucket.com/albums/g1...ps73796630.jpg |
That motor is a beast!
|
Hehe, I hope so.
Couldn't find much information on TP Power motors, just that the boating guys seem to like them. |
Hi Lizard!
Finally registered here just to be your groupie! :lol: Anyway, was wondering if your TP also has such high magnet drag. Can you turn the shaft easily by hand? With my TP4070 it's hard to impossible to do so without the grip of a pinion on it. In comparison, the 1717 spins very freely. Wondering if that is why my motor sounds so loud in my onboard vids compared to other set-ups (including yours) I've seen (yes, I'm assuming it's not caused by be me messing up the gear mesh). Also wondering what high magnet drag would imply (if any) with respect to performance. Not sure how valid it its, but I read that it indicates the armature coils are wound around an iron core, which interacts with the magnets' static magnetic field at all times, even when the motor is un-powered. The iron core channels the electromagnetic field produced by the armature coils so it can interact more strongly with the static magnetic field, meaning motors with iron armature cores can produce more torque than motors without them. Again, don't know how valid that all is; interested to hear other's opinions. Looking forward to seeing your TP5670 powered Slash! |
Quote:
|
Cool, nice to have you here Dr. T.
Not sure about magnet strength and drag and how it affects torque. But what I've read is, that Lehner motors have very little magnet drag. They don't have iron cores (not sure what that is in english, it's called "Luftspule" in German, direct translation would be "air-coil"), so that thing about the iron core causing this seems to make sense. With the TP5670 I can turn the shaft by hand, but it's a lot harder than with the 1717. |
Quote:
|
The motor is on the car now. Fits perfect :)
Motorplate is made of a 4mm thick black anodized heatsink plate I ripped out somewhere some time ago. Hope that helps a little with cooling. The plate is still a little big, will probably make it a little smaller and drill holes for weight reduction someday. Slipper has been replaced with a HotRacing Heavy Duty slipper for the Revo 3.3. This one is even bigger than the Robinson Racing Slipper. What's nice is that the slipperpad is completely surrounded by the aluminum plate, so the pad cannot rip apart like it did on the Robinson slipper which only has a hex in the middle. Now I have free choice with spur gears, the RR Gen3 Slipper was only available in 38t. Drawback with the HotRacing Slipper is that it's heavier with a steel spur. Have now used a 36t Traxxas Plastic spur to keep it light. Hope it'll hold up. Because of the motor with 1130 instead of 1260kv I had to re-think gearing. The initial plan was to grind down the motorshaft to 5mm so that I could use RC-Monster or Tekno-RC 29t and 30t pinions. Due to the lower KV the gears got bigger than planned (30t would only allow for 179kph gearing max.), had to cut the chassis and dremel the motormount quite a lot. But now I can fit 34t pinions without problems. Used a Kershaw Design 8mm Mod1 pinion, with that I can gear from 171kph to 202kph. Nice is, that I don't need to grind down the motorshaft. Bad is, that the Kershaw pinion is very heavy. I guess the best thing to do would be to use an aluminum "pinion to spur adapter", it allows to use Traxxas spur gears as pinions. Assuming that plastic holds up, this would be the easiest, lightest and cheapest solution as Traxxas spur gears can be had everywhere for a few bucks. And you can swap around gears from the slipper to the motor. Have also connected the ESC to a PC and made some screenshots of the software and settings for people interested. http://i54.photobucket.com/albums/g1...ps97c40602.jpghttp://i54.photobucket.com/albums/g1...psbeba86ae.jpghttp://i54.photobucket.com/albums/g1...ps63e3856b.jpghttp://i54.photobucket.com/albums/g1...psd161aa66.jpghttp://i54.photobucket.com/albums/g1...ps56034a1a.jpg |
Screenshots of the ESC software and settings:
http://i54.photobucket.com/albums/g1...ps0881b6bc.jpghttp://i54.photobucket.com/albums/g1...ps5248f72f.jpghttp://i54.photobucket.com/albums/g1...ps90d57bef.jpghttp://i54.photobucket.com/albums/g1...ps25a3b3bd.jpghttp://i54.photobucket.com/albums/g1...ps3c3cfff2.jpghttp://i54.photobucket.com/albums/g1...ps98bf394e.jpghttp://i54.photobucket.com/albums/g1...psf05ecf29.jpg |
Okay, almost done. Just the receiver needs to be placed somewhere and cables need to be tidied up.
Weight is 4240g now RTR with 8s 4000mAh Turnigy Heavy Duty Lipo made from two 4s Lipos. ESC is about 250g with cables like on the photo, Motor is 960g, battery 950g. That makes the Powertrain about half the weight of the car and the motor about 1/4 the weight. Sounds like a good ratio to me :D Gearing is a 32t Kershaw 8mm bore mod1 pinion with 36t Traxxas plastic spur. Theoretical speed with 3.7V per cell, 1130KV and the 97mm GRP tires should be 190kph or 118mph. What I don't like about the Kershaw pinion is that it's quite heavy with 47g, I hope I can use a lighter alternative later. Springs are now +20% Traxxas springs with 70wt fron and 60wt oil in the rear. Needed one more preload clip in the rear, apart from that it feels about the same as the setup before with 3.6kg car weight, +10% springs and 60wt/50wt. We'll see how it goes. Shimmed the front bearing carriers and replaced the inner and outer hinge-pins with 4mm pins from a Savage. Also installed the STRC steering. Now the front is almost slop-free. Powered up the ESC for the first time (on a bench, no running yet). What's strange is the throttle calibration. There is no "calibration-sequence" (so that the ESC can learn the ms-values for the endpoints) you can only choose "Automatic" or fixed ms values in the software. I am wondering how does the ESC determine this? I mean, when I apply half-throttle, the ESC has to know the ms values for neutral and for full-throttle, so that it can apply half throttle at a ms-value that is in the middle of these two values. Determining the ms value for neutral is easy of course, it just needs to look at the value that is present after powering-up, but how does it know what the full-throttle ms-value is? What's also strange is the throttle feel. When pulling the trigger a little, the motor starts, but then stops again, you have to pull it further to keep the motor running. Also, when pulling the throttle very slowly, the motor doesn't start at all, I can pull it (very slowly) fron neutral to full-throttle without any motor movement. Weird. I hope that is just because it was with only 25% max. throttle setting in the ESC (for testing) and that it will be alright when driven on the street with 100% throttle setting. The Castle Controller was very nice in this regard, lots of settings regarding throttle feel and very good throttle response, controlling all the power was never an issue. http://i54.photobucket.com/albums/g1...psa6bd69d8.jpghttp://i54.photobucket.com/albums/g1...ps250b07db.jpghttp://i54.photobucket.com/albums/g1...ps2d9bfc9d.jpghttp://i54.photobucket.com/albums/g1...ps74e66ba6.jpghttp://i54.photobucket.com/albums/g1...psd8bc8893.jpghttp://i54.photobucket.com/albums/g1...ps9e003222.jpghttp://i54.photobucket.com/albums/g1...ps6c81b917.jpghttp://i54.photobucket.com/albums/g1...psed85853d.jpghttp://i54.photobucket.com/albums/g1...psa31196c6.jpghttp://i54.photobucket.com/albums/g1...ps47d549eb.jpg |
Well, as it turned out the motor and ESC came wired the wrong way (not like I asked to have it wired ...), i.e. it's spinning in the wrong direction.
Googled a bit, because I already had the feeling that just swapping two phase wires wouldn't be okay because of the sensors. Looks like I have to try six combinations for the phase wires and six for the sensor wires. So in worst case, I have to try 6x6=36 combinations :( Here is some info on sensor and phase wiring: http://www.endless-sphere.com/w/inde...rushless_Motor |
Thats not good.
|
Looked again at the sensor wiring, seems it's 36 total possible combinations, but more than two of those work.
Basically, it's easy. There are six possible wiring combinations for the phase wires, and six for the sensor wires.Of those six combinations, three are working for one spinning direction and three for the other direction. Now that I already know that I have a "good" combination it's even easier. Just had to swap the phase wires and then try combinations for the sensor wires. Since I already know that I need a sensor combination "spinning" in the opposite direction, I could narrow it down to three possible sensor wire combinations. Was lucky, the first combination worked :) Finally, weather and time permitted going outside for the first run. First test was with 6s and 75% max power setting. It ran okay, but cogged a little. Increased start power in 5% steps until cogging stopped, with 45% start power there is absolutely no cogging anymore, great. Startup is a little "jumpy", i.e. you have to move the trigger quite far to get it going, and then it immediately "jumps" from zero to about 5-10kph speed. But it is able to run slow without any cogging like a crawler when releasing the throttle a little after startup. Well, not a real issue for me, as I don't drive slow anyway. Apart from the startup it runs very smooth in every situation. What I like is that it coasts very nice, i.e. after releasing the throttle it doesn't slow down too fast on it's own, similar to a nitro car with a clutch. Braking somehow doesn't work. When applying the brakes, the car brakes for a very short amount of time (1/2s maybe) and then keeps on rolling until right before coming to a full stop (maybe 10kph) then it brakes again. Tried different brake strength settings, that changed the amount of brake applied within that half second, but that's it. Thought it may have something to do with reverse, so I disabled reverse in the ESC software. After that, the ESC wouldn't run at all. It would beep like it was armed, but no reaction to throttle, neither direction. Temps after about 5mins of running were about 35C for the motor and ESC. Next test was with 8s and 75% max power setting. After 2 minutes of running the plastic spur melted, seems like the slipper was too lose (screw about 1/3 turn open). Replaced it with a 36T HotRacing steel spur and cranked the slipper nut all the way down. Seems to hold up now. After about 5mins of running, motor temp was about 45C, ESC temp 35C. Outside temp was 21C. Seems quite high, considering that it was limited to 75% and I didn't go too fast as I had no brakes. After two more minutes of running, the car suddenly stopped and did not react to throttle anymore. Receiver was blinking fast red, thought it was a receiver issue first, but then noticed that the fan on the ESC also stopped working. Re-plugged everything, ESC startup beeps are there, but receiver still blinking and ESC fan not running. Went home and tried another receiver, same problem. Then measured the voltage coming out of the ESC BEC. It's only 3V, seems like the BEC is toast :( Wanted to try an external BEC for testing, but it seems while testing my TQI Transmitter somehow died. No lights, no nothing, just dead. Now I have to wait until I get a new transmitter :( [youtube]C7noDHnsWjU[/youtube] http://i54.photobucket.com/albums/g1...ps364a7193.jpg http://i54.photobucket.com/albums/g1...pscbf2e3ea.jpg http://i54.photobucket.com/albums/g1...psb116c518.jpg http://i54.photobucket.com/albums/g1...psfe4076b8.jpg http://i54.photobucket.com/albums/g1...ps07c05a57.jpg http://i54.photobucket.com/albums/g1...ps06b3ebc6.jpg http://i54.photobucket.com/albums/g1...ps57bdd89f.jpg |
Long as you keep making some progress.
Looking pretty good. Nothing like good power in an RC to get you happy. |
Hi Lizard, how's it going? Got the ESC working properly now?
Could you do me a favor and measure the base part (outer diameter and length) of that 8mm bore mod 1 Kershaw pinion you have please? I'm wondering what diameter "motor mount hole" those pinions would require to work properly. I decided get a Kyosho GT2 to put the Turnigy 5682 in (I know... GTs suck in real world, but I'll figure that out how to deal with that later :)) and am looking what gearing options there are. I would need around ~50/34 (pinion/spur) gearing to gear for ~100mph... I will probably replace the center diff with a spool with Revo spur, but pinion is still a bit of a question. Kershaw has these huge 48, 53 and 60T pinions, but they're going to be very heavy, and I think I would want to try a plastic pinion first given those sizes; the standard Revo spur-to-pinion adapters could work, but those Revo spurs come in 40T max I think. Might see if I can get an adapter for some standard 4-screw spurs, or 1st speed nitro gears as sold here on RCM. A spur-to-pinion adapter for the XO-1 spurs would be cool too, but I don't know really how feasible that is. Don't you have the same problem finding pinions for your XO-1 with the Turnigy motor, or are you going to run 8S on it? Cheers! EDIT: Sorry to clutter your thread Lizard, but I know you have one and are likely able to help me out :). Do you know the diameter of the center hole of the XO-1 "cush drive key"? Wondering if it can be used to have XO-1 spurs as pinion, with the added bonus of having "Cush Drive": http://www.rc-monster.com/forum/showthread.php?t=32150 http://www.traxxasmodels.co.nz/images/6465.jpg |
Not sure about the ESC yet, need to test the sensors first and then try if it runs. Weather is nice and I have finally received my new transmitter, will probably find out later today...
Diameter of the base is 14mm. Regarding the low-kv motor and the XO-1: Will only run 6s on it with that motor. It's not that bad on the XO-1 because it has 2.85 diff ratio and 4.29 inch tires. I went with a Revo 3.3 Slipper that can run 34t to 42t spurs, that gives me enough gearing options. |
Hi Lizard, how's it going? Got the new suspension dialed in yet?
I was wondering if anyone here has some recommendations for diff fluids for on-road speeders. I read on-road racers typically use heavy or locked front diff and around 10k cSt rear diff. I'm working on an Inferno GT2, 5682 motor, center spool, RTR weight will be about 4.5 kg, geared for 90 mph and up (depending on what motor will be happy to pull for continuous use). I'll be running 2° rear toe (instead of stock 3°), as Mike suggested below, to free up some speed, but have no idea if I should compensate that with a bit of a lighter rear diff fluid in order not to lose too much rear end stability. Any ideas? What would be a good starting point for rear and front diff fluid, yielding good balance between straight line stability and handling (I'm not talking about serious track use, I just don't want it to be a straight line speed runner only that does not turn well)? Quote:
|
Haven't done anything on the suspension yet, the motor/ESC doesn't run smooth anymore since the BEC died, it's stuttering, even with external BEC. Bruno wants me to send in the motor and ESC, but haven't had the motivation to do so yet. I'm getting fed up with wrenching lately :)
Regarding diff fluids: From what I have read, for onroad straight-line hard acceleration it's better to go for a quite thick diff fluid in the rear because it helps to maintain the same wheelspeed on each side. With thin fluid it can happen that one side has more grip and then the other side just spins which will throw the rear around as soon as it gets traction again. I think I have experienced that effect when trying to achieve maximum acceleration from a standstill. When you look in the the video at 0:57s you can see how the car at first runs straight, then the rear steps out a little, I get scared, let off the throttle and after that the rear passes the front. http://youtu.be/EVJkGJpTDKI?t=57s At 1:46 in the video I managed to keep it straight, I think that was because I didn't let off the throttle which allowed the spinning tire to get grip gradually again (by the "natural" reduction of torque with higher RPMs). http://youtu.be/EVJkGJpTDKI?t=1m46s Always wanted to try a thicker fluid in the rear, but haven't done that yet. The diffs have the XO-1 stock filling with 100k front and 10k in the rear. |
Sorry to hear of the troubles with your Alien stuff :(. Was really looking forward to seeing Godzilla Slash in action a bit more.
Hoped the Alien stuff would be a nice alternative 8S option, but given your experiences, I'm really leaning towards XL2 now. I read the concerns you mentioned of Ub3r on rcgroups, about the long distance between drivers and FETs, but it seems it's still the best option. Seems the reported cogging issues, like the one Othello posted here could be heat related, so with a bigger fan, in a ~4.5 kg car, and with a bit of luck :), I'm hoping it'll work fine. Thanks for the XO-1 set-up as reference. I'm using 20k/10k (FR/RR) in my Truggy, but the 10k is a bit light and it seems to be leaking, probably due to getting hot. I also have some 40k cSt and 500k WT (Traxxas stuff, read someone reporting it to be actually thinner than his 300k cSt FG fluid), so I think I'm gonna rebuild the diffs with the 500k WT front and 40k cSt rear. Hope you'll be wrenching again soon man, looking forward to seeing twin truggy updates :). |
After I have been pretty de-motivated last year (system was stuttering after a few testruns and on top of that my transmitter broke ...) I finally found the motivation to send the motor+ESC to Bruno :)
Just heard from him, that one sensor on the motor is defective, he's going to replace it now. Well, let's see ... |
Some news.
The Alienpower ESC and the TP5670 are still not returned to me (despite me asking several times), but Bruno promised that I'll get it this week. At first he told the ESC will be repaired, now it'll be a new one because the old one was too heavily modified by me (?) Not sure why that is, I didn't do anything beside cutting the heatsink a bit and applying Plasti-Dip. Well, getting a new one is nice, but now I'll have to redo all the soldering and cutting the heatsink :( Since the weather was getting better and I wanted to drive, I put the Mamba and the 1717 in again. Runs reliably, as always. Springs/Oil seems a little on the hard side now with the lost weight compared to the TP5670, but it was driveable. Also tried out the new black-spoke GRP slicks. They look really nice, but traction is not as good as with the treaded ones. Ran it for a few minutes with a lot of throttle, after that the rear tires were almost too hot to touch. Clearly a sign for not enough traction :) Somehow I have the feeling, they are a different rubber compound. And the VESC finally arrived and was installed in the car. Started the software, ESC gets recognized by the software, nice. Then started the "motor detection" routine and nothing happened. Fault eventlog gives: Fault : FAULT_CODE_DRV8302 Current : 1.9 Current filtered : 0.2 Voltage : 23.09 Duty : 0.01 RPM : 0.1 Tacho : 5 TIM PWM CNT : 3872 TIM Samp CNT : 3878 Comm step : 2 Temperature : 27.31 Looks like the FET driver chip is broken. Still unclear why that happened, I'll send the VESC and the 1717 to Benjamin so that he can have a look at it. http://i54.photobucket.com/albums/g1...psgug5onr0.jpghttp://i54.photobucket.com/albums/g1...psiio54auo.jpghttp://i54.photobucket.com/albums/g1...pscddhnvbc.jpghttp://i54.photobucket.com/albums/g1...psnaz5e7mn.jpghttp://i54.photobucket.com/albums/g1...ps6f2ofaq0.jpghttp://i54.photobucket.com/albums/g1...ps99ifw6b2.jpghttp://i54.photobucket.com/albums/g1...pssvisqilb.jpghttp://i54.photobucket.com/albums/g1...psikfjfwpl.jpghttp://i54.photobucket.com/albums/g1...pst9pbba90.jpghttp://i54.photobucket.com/albums/g1...ps790fo0zf.jpg |
Nice to see you got the Slash out again!
Crap to hear the GRP slicks have less traction (which compound do you have?)... :( I haven't tried mine and hadn't realized it yet, but reading your post and comparing the two compounds, the slicks indeed feel like different material, not with the "stickiness" of the treaded ones. Are those treaded ones in your comparison pic above also from this year, or from last year (just wondering whether they migh have changed all compunds for this year)? Seeing your car again also reminded me I still have some work to do on my front wing :). I got a couple of wing options and I think I'll use a small lexan 1/10 ST wing. Looks most natural to me size-wise and is actually a very good copy of your design :). Still have to do a little trimming of the sides and will have to add some foam behind it for rigidity, but below is how it is going to look. Did you experiment with different angles of your front wing? Have you had issues with the car scraping the ground when on speed? http://www.rctech.net/forum/members/...0867-photo.jpg |
Yeah, really sucks with those GRPs. I tried the S3s and had the feeling they have less grip than the treaded S5s I bought last year and also this year a few months ago. Maybe the S1 slicks come close to the S5 treaded ones, but I think I'll just stick with the treaded ones, they always worked well for me in S3 and S5.
With the frontwing I seem to have gotten it right (or atleast good enough) the first time, did not experiment with angles so far. It sits pretty high, no problems with srcaping the ground at all, I also can go up lowered curbs in case I need to get out of the way when real cars approach. (BTW, it's really funny, I would estimate about 95% of car drivers actually treat my little car as a normal car that's bound to traffic rules and give right of way to it etc.) When the front suspension is fully compressed, there are a few millimeters left. |
Offtopic : @ Dr.T, what car is that in the background, with the Badlands?
Kyosho Scorpion? |
| All times are GMT -4. The time now is 06:00 PM. |
Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2026, vBulletin Solutions Inc.