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markkat

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About markkat

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  • Location
    Michigan, USA
  • Interests
    Reconnecting with RC after 30 years. Restoring/revamping my Tamiya Frog, and building a new custom buggy.

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  1. The Frogtima project continues! I've lapsed a bit with taking photos of the process. Since last update, I have added shocks (Team Raffee double spring) on the front and back, and decided to use the Optima mounts. The rear mount was reversed with the gearbox, but it had little impact on the placement. I also used the Optima sway bars, although the back sway bars needed some trimming due to the gearbox flip. I mounted the front shocks to the arms rather than the hubs to make them more vertical than horizontal. I also added wheels and tires. The fronts are Proline Hoosier's (I rubbed the logo paint off), and the rear are some generics I got off ebay. As mentioned, I'd like to get a 70's Funco look to the buggy, so I'll probably replace the rears with a different tread. The biggest challenge thus far was the steering servo. I finally went with a AGFrc 8.5kg coreless servo that was both small enough yet provided enough torque. Mounting was a bit tricky, but I eventually got a setup that worked. There's no servo-saver, but direct was good enough for the Frog, so it's good enough for the Frogtima. We'll see how that works out. I'll likely trim the top mounts off to make room for the body. I'd like to get the hood as low profile as possible. I have some bent ball links coming that will bring the steering links more perpendicular rather than sweeping back, which will reduce the impact of vertical wheel travel on the alignment. The Frogtima has a healthy amount of ground-clearance. In the future I might get some shorter stocks for a lower optional stance. I am happy with the look. My next steps are a bit of a rear roll cage, as well as a driver roll cage. After that, I am going to attempt to create a body with a flat piece of lexan and a heat gun. That should be interesting...
  2. The journey continues! Some time on vacation and bashing about with my proper Frog, led me to consider more options for the Frogtima. I came back and did a 180, literally: I turned the Optima gearbox around and went for a mid-motor setup. I also painted the Frog chassis black. I tried Rit dye, but it didn't take very well, except for the spots where I cut and sanded it. I used a plastic-bonding primer. I'm sure it will scratch over time, but I can live with it. I think it looks pretty sharp. To make room for the motor, I needed to extend the bottom plate, taking the wheelbase from 268mm to 290mm. It's still within ROAR's 292mm for 1/10 scale, but just barely. It's not going to be the lightest buggy, but I think it will be well-balanced. I decided to go with the stock rear shock mount, and I am waiting for a replacement to arrive since I hacked up the original. Next step is the steering.
  3. More Frogtima Buggy! My first step was staring a this for a while and trying to figure out how to join the two: I cut off the top of front Optima gearbox, but left the lower swing arm portion. However, it didn't make sense to keep the Optima knuckles and axles, so I ordered some Ultima SC6 knuckles, and was pleased to find that I could add them with just the addition of an aluminum spacer. I also did some cutting into the Frog chassis, and finally figured our how the Optima front could be attached. The front was a bit too pitched up, and it took some working to get it right. However, once I had it figured out, I extended the bottom aluminum plate to fasten to the front assembly, and ran some aluminum bands from the chassis to the top. It is solid as a rock, and lighter than it looks. I think a black Frog chassis would look so good, that I am tempted to replace it with the black version. However, I have some black Rit DyeMore, and I will see what effect that has. Any advice would be appreciated. You might have noticed that the wheelbase is significantly longer than that of the humble Frog. The Frog has a 250mm wheelbase, whereas the Frogtima's is currently about 268mm. According to the ROAR Rulebook, the max for an off road 1/10 buggy is 292mm, so no issues there. I can actually extend it to 270mm by moving that spacer, and I might just do that. An odd beast. I'm really starting to like this Frogtima. The next step is figuring out how I am going to get a servo into the front end. I am going to look into some smaller servos. If anyone has a recommendation for a micro servo with enough torque, I am all ears. After that I am going to figure out the shocks. I decided against using the Optima Golds. Both for aesthetics, and because there is enough Optima in this thing already. I can use the front shock mounts as is, but am going to have to get creative with the rear shock mounts as I don't have any upper options atm. To be continued...!
  4. Thanks everyone! It worked. I did about 3 min on mi NiMH charger, then switched to the lipo charger, and it recognized it. No swelling, no heat. No explosions. I’ll take it for a spin tomorrow.
  5. No. This is the setup. I am flying blind... O_o I do have an old meter though. I'll try it first.
  6. Thanks, @mtbkym01 and @matman. The Frogtima Buggy project continues. The next step was to attach the dog bone axles and the upper rear arms. As I had previously chopped up the Optima mount that holds the upper rear arms (and rear shocks), I had to create a new solution. I found the placement for the arm mount attachment could be matched by extending some aluminum spacers from the Frog chassis. I drilled some holes: and attached the spacers on M3 screws coming from the inside. Slightly hacky, but not terrible. The ball mounts for the arms screw nicely into the spacers: Thus the rear arm was mounted. The arm doesn't take a lot of force, but I wasn't crazy about the leverage it had on that spacer, so I added some screws (and aluminum tube sheathing) coming from the gearbox into the spacers. This firmed up the mount, and also increased the strength of the Frog/Optima connection. Not too shabby. The next step it to figure out how I am going to mount the shocks. I have the Optima Gold shocks on hand, so I might start with those, and replace them for style if I can find something more suitable. If anyone has suggestions on for good performance shocks, I'd appreciate it. Extra points if I can find some that are white. I'm starting to dig the Frogtima!
  7. All right. It sounds dangerous. I'll try it on the driveway! Thanks, @Mad Ax! @Wooders28 stand by. I need to dig out my reader.
  8. I have a relatively new 2S 5000mAh lipo and accidentally left it plugged to the ESC for a few days. I believe it fully discharged, and doesn’t seem to be taking a charge. Is there any hope for it at all? I has no damage or swelling.
  9. I have a lot of spare parts for two 1/10 RC cars: the Kyosho Turbo Optima, and the Tamiya Frog. My quest is to build a performant 2WD buggy that looks good, relying heavily upon the parts I have. My goal is to have something that looks like a late 70’s Funco buggy: This will likely be some time in the making, but I'll post my progress here along the way. The Optima has great motor placement compared to the Frog: low, rear, and centered. I only needed to seal the gearbox where the chain/belt feeds out, as I will be forgoing 4WD. My first requirement for this buggy is that the battery is as low as possible and centered. With a new bottom, the Frog chassis accommodates a lipo lying flat right down the middle. I bent and cut some aluminum sheet for a bottom plate to arrive at this setup: The Frog chassis already has much of the shape I want, but I shaved off some protruding parts, including the side mounts for the antenna. I’ll probably dye the plastic later in the process. The way that the Optima rear arms attach provided a simple opportunity. The arms swing on pins that insert from the rear of the gearbox. All that was missing was holes to support the front of those pins. To both join the Frog bottom plate to the Optima gear box, and to provide holes for the rear arm pins, I cut a piece of square aluminum rod, and drilled holes for the pins and the screws coming in from the sides: Aw yeah. Frogtima!: The next step was to solidify the hybrid connection. To do this, I trimmed some of the Frog’s upper body mounts back and cut some aluminum strips to create a bridge to the top of the gear box. I used a threaded aluminum spacer, and put it together: The connection has no wiggle in it at all. It’s almost as if it were meant to be. 😊 My next goal is going to be getting the rear dog bone axles inserted, and the upper connectors for the rear arms installed. After that, I’ll be adding the rear suspension. I still have the Turbo Optima gold shocks, but I will probably get some that look more appropriate for the 70’s style I am after. To be continued…
  10. Thanks, RichieRich. I totally agree. There's just something about the Frog. What it lacks in performance, it makes up in character.
  11. After improving upon the Frog's balance, my quest has become to do something about the front suspension. I think the stock suspension is genius, but it would be great to add some dampening. I did some research, but all of the damper modifications to the front suspension really detract from the look of the Frog, IMHO, and I wasn't about to cut the body to allow for mounts. Currently, I am halfway to a solution. First, I cut some aluminum from my scrap Optima, and created a small front mount that didn't require cutting the body, or look out of scale. Next, I measured the distances a damper would travel, and arrived at 38-45mm. I searched shocks and dampers with those dimensions, but that were also a small diameter. There aren't many, and I settled upon these "The Ultimate Mini Scale Shocks": They are internal spring, not oil, but I am determined to change that. Here's what they look like mounted: I pulled the internal springs, so they aren't functional yet, but the travel is there and smooth. The lower chamber of the shock can be opened, and I am hopeful that a very small and flat o-ring/soft-washer will enable it to hold oil and still glide. Any suggestions are appreciated.
  12. Putting the steering servo and receiver in-line presented a re-balancing opportunity. My Lipo (and new motor) arrived, and voila: The Frog is almost completely balanced on the center line, and the center of gravity has been moved forward by nearly an inch. More to come...
  13. As I waited for my Lipo battery to arrive, I started to look at the positioning of what remained. It occurred to me that with removing the MSC mount plate, I could put my receiver in-line with the steering servo. I did this, and replaced the MSC plate with a square aluminum rod: My thinking behind this was that any weight on the left was a good thing, to offset the large imbalance caused by the side motor position. (You can also see a front-suspension mount, but more on that later...) Looking at this setup, gave me an idea... One thing I noticed as I drove my Frog, was that the front wheels are really pushed about. I believe that part of that has to do with the front suspension, but it is also a result of the car's center of gravity being so far back. Here's a video of an early drive that demonstrates that:
  14. Thanks! It's great to know where that body came from. I always preferred the proportions of it. As for the plastic, I thought that might have been the case, but have been pleasantly surprised. The only break I've had thus far was a cup on the steering rod. That reminds me, however. Upon adding the new shocks, I did add some fiberglass reinforcements to the rear arms where they attach. The twist on those arms was disconcerting. Also, you can see in the second photo above that the front attachment for the left rear shock is a melted mess. That was the result of me trying to force a Kyosho Optima gold shock on it around 1987. It cracked, and I melted a repair. I've since got a re-re frame, and replaced that half of the frame. It's already an anachronism, I guess. As for putting her on the shelf, I am not a collector, and it just doesn't feel right for me. There's something very cool about seeing my old Frog tear it up again. Anyway, I put in the new ESC, and started to enjoy the new F/Br/R configuration. I did have to open my Futaba Attack transmitter and manually reverse the throttle control by re-soldering the wires, however: Unfortunately, I found that after running with my 360 Gold or 240S motors for about 5 minutes, the car would start to drive at half speed. The NiMH was new, and it happened to both batteries I had. After some research, I concluded that it must be due to low voltage. In the process, I also disassembled, cleaned and reassembled my Le Mans 240S motor to no effect. As the Dynamite ESC can be configured for Lipo, and as Lipo has a more squared voltage curve, I ordered a 5000mAh Lipo. (My 8yo daughter just got a Grasshopper, so the NiMH's have a new home.) I also picked up a 20T Dynamite brushed motor from the local hobby store. To be continued...
  15. This is the first post on an ongoing process. During the lockdown, my 8yo daughter and I came upon my old Tamiya Frog in a box of our garage attic. I got it for Xmas in 1985 if I recall correctly. This was the state of things: Organized, but dismantled. I couldn't recall why I had pulled the servos and the speed controller. The mods I had last made over 20 years ago were a rear sway bar, bearings (of course), and a new gearbox and dog bone axles after my Kyosho 360 Gold shredded the originals. The two motors I had were the Gold and a Kyosho Le Mans 240S. That lexan body was also a replacement for the original. I ordered a 3600mAh NiMH battery, and stuck the MSC and servos back in there. It looked sharp, and each run lasted for about 10 minutes before the solder on the MSC melted. The smell was nostalgic. After a fiddling with the MSC, and trying a resistor from an old dismantled Turbo Optima (the only other RC I've ever owned, but never loved), I ordered a Dynamite 60A Brushed ESC. You might notice the 4 AAs are still in there. It took me a bit to happily realize that I could lose them with the new ESC. While waiting for the ESC to arrive, I discovered MCI decals. I decided to refresh the look, so I ordered a set of Frog decals, and a spoiler from RCMart. Also, as the Frog's rear shocks leave much to be desired, I got some Boom Racing BRX01 Rear Aluminum Double Spring Shocks. I think the new shocks and decals improved the look (the spoiler has yet to arrive): More of the journey to come...
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