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mike_o

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Everything posted by mike_o

  1. I've been searching the forums for 3D parts, but haven't found anything focused on sharing designs and presenting them in a nice way. Did I miss anything, or has 3D parts not really taken off here yet? I do a lot modding, and often find my self missing a frankenpart that would allow me to complete a build in an easy way. For instance, I'd like to have a set of rims that fits the Padlatraks tyres, but goes on a hex wheel hub. Currently I'm using a set of Mini rims, but the are too narrow for the tyre to fit properly. I imagine printing a set of wider Mini-like rims would be the way to go. Would it make sense to have a library thread, or should the dokumentation go elsewhere?
  2. I'd pick one of Runcams HD cameras, probably the Runcam 2 HD, which supports 1080p at 60fps. The higher framerate helps making things less shaky, and it's easy to make a simple 50% slow-mo conversion without loss of quality. Also, consider getting the wide angle option as the more wide angle lensed cameras seems less susceptible to shaking. http://shop.runcam.com/runcam2/ At $80 they are hard to beat, and they even have a metallized casing prevention rf radiation that could interfere with your receiver. There is a smaller alternative, the Mini Moebius, which also provides 1080p at 60fps, but the video quality is slightly (very little) lower in some conditions: http://www.ebay.com/itm/Mobius-Mini-A-Lens-Super-Light-FPV-Full-HD-Pocket-Camera-1080P-60FPS-H-264-AVC-/162177778578 And work on the mount to avoid shaking. I find that any kind of rubber mount tends to produce shake and jello, so I go for a firm connection to the chassis.
  3. Winter seems to be over, and I never finished the build (body missing). Possible hibernation or sell off to somebody with more time than myself? The chassis works very well and is the most terrain/snow crunching Tamiya build I've ever done. Any takers? Rolling chassis with 6 x 135mm wheels, nice shocks, dog bones, drive cups, suspension, and servos. Fully ball raced, just add your preferential motors and ESCs. (and wheel spacers / Wild Dagger rims for best turn radius). 150 EUR + shipping. Stock parts value at least twice the asking price. Everything as new. Add 100EUR to get 3 pcs 3536mm 910kv motors and 30A ESCs and it's receiver ready. Also new parts for this build.
  4. Winter seems to be over, and I never finished the build (body missing). Possible hibernation or sell off to somebody with more time than myself? The chassis works very well and is the most terrain/snow crunching Tamiya build I've ever done. Any takers? Check out the thread in the Monster Truck section. Rolling chassis with 6 x 135mm wheels, nice shocks, dog bones, drive cups, suspension, and servos. Fully ball raced, just add your preferential motors and ESCs. (and wheel spacers / Wild Dagger rims for best turn radius). 150 EUR + shipping. Stock parts value at least twice the asking price. Add 100EUR to get 3 pcs 3536mm 910kv motors and 30A ESCs and it's receiver ready. Also new parts for this build. Everything as new.
  5. I liberated an bunch of ESCs from the other cars to get the Stolly going while the snow is still here: Sorry for the poor camerawork, but it's kinda difficult to drive and shoot at the same time...
  6. Poll: If you had one how often would you update it ? Could I have more choice than "several times a day", pls?
  7. After putting more load on the vehicle, the 2.3 to 3.2mm plastic "adaptors" (27MHz antenna tubing) went soft, so I had to mount the 35mm outrunners after swapping their 4mm shafts for stepped 4/3.2mm shafts instead. It then turned out that the "one ESC for several, sync'ed BL motors" didn't work in real life. I had tried it on the desk several times, and I think it will work on a plane, but I believe that the mechanical coupling (via the ground) between the motors prevents them from sync'ing up nicely. I had a couple of succesful/synced runs, and it does go like stink now, Will be ordering a bunch of cheap HK 30A ESCs to get on with the show.
  8. Thank you. The shocks are HobbyKing 85mm TrackStars. They are perfect in length for the short suspension arms, and they are nice quality, although not quite so smooth as the RCMart ones I use in the shortened wheelbase Dagger. The latter only comes i packages of 4 pcs, while the TrackStars are stocked in pairs in the EU warehouse. Using the L-shaped ALU profile turned out to be a really good idea. It's light, rigid when fully assembled, and very flexible to work with. I even did some of the joints with double sided foam tape to avoid weakening the beams (and out of laziness, of course). This is what the transmitted look like (almost, the original PAL baseband signal is better than compressed, digitized video recorded and required for YT upload)
  9. Hehe, that was tempting, but it's still spending a lot of time on the work bench, so I prefer to keep it clean for now. However, the promised winter has arrived, so (from the comfort of my sofa and the LCD TV) I took it for spin round the house: I now run the Wild Dagger Spike Tires on the 2 front axles and the slightly larger HK wheels on the rear axle. Interestingly, the snow stuck intensely to the Tamiya wheels, whereas the HK ones let go of it... As posted in the "What have you done today" thread, the small, brushed 365 Mabuchis doesnt have quite the torque required and I cant drop the gearing anymore (running 14T pinions for the 18/20T layout), so the 3536mm 910KV outrunners are going in shortly. Depending in the load, they'll provide 10-20 times the power of the 365 cans.
  10. I took my 6x6 Stolly out for an FPV test drive in the first snow. Works quite well, although the RS-365SH motors need a little torque for the big wheels. Description of the build in the "Monster Trucks,.." thread
  11. I've driven a bit more and I'm very pleased with the chassis. Need to use a thinner shock oil, as thing get a bit bumpy at speed. Also, I managed to break the stock servo saver spring ring. Fortunately, I got two more, as I got 3 packs of the plastic parts containing these. I use a smaller servo for the middle wheel, as they turn less ans has a lower gearing. This servo has no saver, though, as I reckoned the middle wheel are fairly protected... Finally, I decided to go with the 130mm Wild Dagger spike tires/wheel. I have 4 new ones from above biuld, and I ordered a pair for the reamining axle.
  12. I think there is another aspect to the NiMh vs Lithium technology discussion, and thats weight. I've built a number of basher buggies for the kids, and the lower weight of a 1800mAh LiFe (136gr) makes a major difference to the damage report after going head-on with the kerb or another buggy. At the same time the lower weight frees an agility rarely found in brushed motors. Even a stock 380-motors, the Grashopper becomes a real hopper on light LiFe pack. If fitted with ball bearings and prevented from being bogged down it will live with 3S LiFe operation. Hobbyking has 1800 and 2100mAh 2 and 3S pack on stock - also in the local warehouses at $10-15. Beat that for fun and speed.
  13. Winter is forecast for next week, so I have accelerated the Stolly build. The platform is now running, albeit with small wheels (clearence problems with the 135mm ones) and small RS-365 Mabuchi brushed motors. Still it works very well, and I'm surprised how smooth it is.
  14. Failed upload on 2nd picture, am I only allowed a certain MB per day/thread/post???
  15. I decided to skip the articulated chassis and go stolly-style. The chassis is almost done, missing servos, BL motor mounting and some track width adjustments, but I'd like to share a few pictures:
  16. Nobbi, in my build, the gearboxes are oriented in the same direction, so the motors spins identically. But swapping two wires will make that motor run in the opposite direction. I did test that on a two motor set-up.
  17. Nice buy! It looks very new. The problem with the Sport Tuned motor (and most other motors) is that it is not neutrally timed; It runs much better and efficient in one direction. And in the Tamiya Twin Motor series, the two motors run in opposite directions. The best solution is to find a pair of motors with adjustable timing, and trim the reversed one of them back to negative advance, or to get a pair of brushless motors. However, these chassis are not really up to brushless power. The suspension is wiggly and the dogbones break or pop out. Alternatively, you could run the stock silver can motors on 3S LiPo, if you use the smallest pinion, ball race it, and refrain from bogging the car down in mud or long grass. 3S really fires her up.
  18. Edited: The one ESC for several, sync'ed brushed motors didn't work in real life. I tried on the desk several times, and I think it would work on a plane, but I beleive that the mechanical coupling (via the ground) between the motors prevents them from sync'ing up nicely. I just made an interesting discovery today: I have always assumed that you could not run more than one (non-sensored) brushless motor on one ESC due to the specific timing and EMF feedback circuit. But it is actually possible, and you even get the benefit that the two motors will run perfectly syncronised. To see for myself, I hooked up a pair of NTM 3836mm 910kv motors on a single 18A ESC and switched it on. The ran just flawlessly and the ESC didn't seem to suffer. It turns out that the motors actually help each other to stay in sync; If one looses out, the slight timing advance of the other will transfer energy to the other, thus helping the ESC. Of course the ESC rating has to follow the sum of the motor ratings, and there is some losses under certain loads that will increase, but this basically very good news for owners of the Twin Motor series (Wild Dagger, Twin Detonator, etc) and for my 6x6 project. I was worried about the mechanical stability, gear / ratio selection, and power output of my 365 size brushed motors, but now it all goes away. I've purchased an extra NTM 3536 motor and three 4mm/3.17mm stepped shafts, so all the mentioned worries are gone. I did have to get an 80A ESC, but the waterproof version were on sale at HK, so it went into the cart along with the NTM and the shafts Will post pictures when the build progresses.
  19. Madinventor, thanks for the comments and the link. That is one intimidating build! I was hoping the reduce servo load by having the pivot point just over the axles, but I sense the challenge. After fiddling a bit more with the suspension and the wheels (and looking at your build), I may even go back to the original idea of the Stolly / Stalwart configuration. Worst case, I'll have to change the wheels or at least swap the foam inserts for taller, more narrow ones. Still no snow here, so I might make it this year Happy New Year all!
  20. As you see from the time since last post, my project hasn't moved much forward, and with the challenge of very little room for the big wheels to turn and little spare time in general, the build came to a stop. In anticipation of snow to come and with a little more time at hand, I have taken it up again and re-evaluated the turning issue. What I have come up with is another idea: To build all three motor/gearbox/suspension assemblies identical with fixed (non steering) uprights and instead turn the entire assembly instead: Central fixed motor assembly with frame/battery/electronics/servos plus forward and rear motor/gearbox assemblies turning on a vertical shaft. [frontmotorassy]---[central motor/frame assy]---[rear motorassy] Clearly, this is no good for high speed turning, but the 6x6 is intended for snow-crawling, so it might work. Or what? Any inputs / ideas? thanks
  21. Oh, the thread came back alive Better post a picture of my dusty shelfer (ballraced QD-Willy with oil-shocks and 3530mm BL outrunner):
  22. The 380 that sat in our Boys Racers all had brass pinions. The 380 can comes in many version, just google "mabuchi 380" and check the datasheets. Nominal voltages from 6 to 24 volts. A major benefit of a 380 motor vs the 540 is that it's half the weight. I bought a couple of Grasshoppers for the kids to bring on our beach vacation a few years back, and they worked very well with full ball racing and 1800mAh 3S LiFe flight packs. The buggies must have been half the weight of a NiMH / 540 powered equivalent Light and nimble on the hard packed sand. Very cheap and straight forward fun
  23. Quite hot is not very specific 50 degrees C is the point when you can no longer hold your fingers on it, and that is a possible max temp level for your motor. From what your describe, I'd suggest you to go to 20 or 22 teeth. I assume the car is plenty fast?
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