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Honza

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Posts posted by Honza

  1. @Gebbly thank you 😃 About designed breaking points - having to reprint a part that takes 6h is something that inspires you 😁 

    There's speedrun challenge going on, so I thought it would be fun to make a quick modification - using smaller spur gear with slightly altered position, I made a "high speed" modification, with FDR ranging from 4,66 to 2,8. Not sure if it has any real use, but it helped me to move forward with the low range gearing.

     

    Resize_20240801_105739_9832.jpg

    Resize_20240801_105740_0461.jpg

    Resize_20240801_105740_0859.jpg

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  2. 4 hours ago, Pylon80 said:

    They sort of did ;) if I am not mistaken they were using a revolutionary for the time system of pneumatic suspension!

    Hydropneumatic suspension. It was really cool system, instead of pumping gas into rubber springs, it used pressurised gas balls and pumped fluid around for ride regulation. The ride was so soft, because fluid would redistribute around the entire suspension when one wheel hit a bump. Guess one could replicate a similarly working system with mechanical linkages on an RC 😁

    The only similar system was Hydrolastic/Hydragas used by British manufacturers (can't name a specific one, since British automotive indistry is a mess, but some Mini Cooper variants used it aswell). I played with an idea to try replicate this setup in an RC car, but it involves lot of weird shaped rubber parts.

    One fun bit of trivia I found recently about the Citroen system is, how its engineers dealt with leaking of the hydraulic cylinders - they didn't 😁 They just collected leaked oil in a rubber boot and pumped it back to reservoir. This is why DS lays on its belly when it's not driven for a while.

    • Like 2
  3. 2 hours ago, chris.alex said:

    Unfortunately, the official parts list still is only available in Japanese. 

    You can use Google translate on the Japanese site. Unfortunately no new information, only the one we figured out here -  #42300 M-chassis set is listed as compatible, with additional information below:

    Compress_20240725_095036_6415.jpg.0c40815898d6585da24ae98104fc30d9.jpg

    42379/42220 are the 3mm 1050 bearings, 42218 is the TRF/M-07 wheel axle.

    So, the option #1 is the official one 😃

    When we are back to the topic of driveshaft, here is the reason why M-05 driveshafts don't work:

    Resize_20240721_203045_5446.jpg.912d08be974e482af26d8ddec476c71e.jpg

    At the top is a 30mm M-05 CVD, at the bottom an M-07 33mm cvd. The cross pin sits some 3mm deeper in the hub. That's also reason why M-05 DCJs don't require thinner bearing.

     

    • Like 2
  4. 9 hours ago, Alex97 said:

    That was an oversight on Tamiya behalf, the work around are ok but I agree that's the only advantage of the M05 over the M07. 

    Not an oversight, intentional choice. Tamiya doesn't have any 210mm FWD shell in production, so they didn't need that WB variant. That made the whole chassis simpler, since they only need to flip rear arms for other two WBs.

    • Like 1
  5. FWD - M-05 with V.2 chassis. Since M-07 doesn't support 210mm WBs without modification, M-05 V.2 is the next best thing.

    AWD - XM-01 - although it's sold as a rally chassis, it has lower suspension position, so it should work on asphalt, too. 

    • Thanks 1
  6. One #51748 set on its way, so in the meantime, I tested an idea to use 33mm CVDs with them. I thought that I'd need 4mm hexes to compensate for longer swingshafts, but turns out, that it's not needed. Wheel axles used on XM-01 are shorter just by those 3mm. :)Resize_20240721_203045_5446.jpg.120c9452e8db00463667003ff240e17e.jpg

    This means that I'll be able to make slightly longer front arms. With starting length of 20mm, each milimeter counts.

  7. On 7/12/2024 at 9:31 AM, chris.alex said:

    Well, I can think of two options: 

    1. DCJ Set 42300 plus 42218 axles plus two 5x10x3mm bearings as @Honza suggested.
    2. DCJ Set 42216 or 42312 plus the 30mm DCJ shafts 19804932. 

    The 19804932 shafts are only sold separately by a few retailers, so the first option may be the right one for most people.

    Thanks for the Info, how did you find PN of the swing shafts? I went through several documents and couldn't find it 😃

    I can see a 3rd option - 19804932 + 42218 + 42219 + 42221 (not sure if it's cheaper option than modifying the whole set or not)

    • Like 1
  8. 1 hour ago, Gebbly said:

    I mean what makes a vehicle competitive and what is it that Tamiya vehicles lack and other manufacturers have?

    - design - while it's always criticised that one manufacturer of competitive chassis copies from another, design "trends" in racing scene have one advantage - jumping from one manufacturer to another is easier because of familiar setups and driving style. It happened numerous times that some manufacturer brang radical design, just to change to more familiar design in the next iteration, while others took some ideas... Overall, the target of the design is performance. Meanwhile, in the less competitive scene, main target is simplicity and ease if manufacture - a typical Tamiya is made of four, five large plastic sprues? These can be made cheaply in hundred of thousands quantities.

    - materials - typical competitive chassis is combination of carbon fibre, aluminium alloys, high quality steel and fibre reinforced plastics. Just like in the design paragraph, these materials are chosen for their mechanical qualities, not so much for ease of manufacture - used alloys cannot be easily die-cast, FRP require higher quality moulds with more frequent cycles, almost everything has to be machined and sometimes heat treated. Non-competitive cars can get away with cheaper materials made to looser tolerances, which don't wear out tooling as much. Metal parts, if there are any, are die-cast, sintered, cut from stock or stamped to save costs.

    - features - this paragraph is most obvious, but the previous ones are IMO more important - you can throw features of racing chassis on a TT-02, but it still won't be competitive due to previous reason. At the same time, mid-range Tamiya can be more competitive even when it doesn't have all bells and whistles and it's still mostly plastic.

    • Like 3
    • Thanks 1
  9. Tamiya did make competitive chassis some 10 years ago. TA05, TB-03 DN-01 and DB-01 were essentially cheaper variants of their TRF offerings. And just like TRFs, they probably didn't sell large enough quantities to be profitable.. TRF range got reduced to TRF4xx, with limited runs of TB-evo, TRF buggies were discontinued entirely, the mid-range reoriented to more experimental designs to various degrees of success...

    I'd say that there's one category where Tamiya is very competitive - rally. While other manufacturers just slap longer shocks on an onroad chassis, Tamiya si far made three different purpose-build chassis from the ground up.

    Problem with all this is, that it's not as well known as their entry and toy grade offerings. Which also tells a lot about why they focus on those.

    • Like 4
    • Thanks 1
  10. 10 hours ago, DTSCB said:

    @Honza Do you remember where you found this picture?  I don't see it on any of the blog links.  The most notable thing about this picture is the white colored slipper pad. 

    I should also note that, the blog is dated back in 2019.  So... I'll see which parts I can still find. 

    I started with the 6mm OD and 5ID pipe... I couldn't find one in brass, like the OOP, but I eventually found one in stainless steel. 

    I'm currently trying to figure out if a tamiya slipper clutch hop-up will get me closer on the parts I need or if this won't be much in the tamiya parts department.

    The picture was in another blog post, linked on the bottom of the post I linked here, there's no other photo of the slipper. I guess that those slipper pads are just another Tamiya option, now for example available for TD4.

    I didn't even realised it's 5 year old already.. yet still no slipper upgrade from Tamiya or any other manufacturer.

    I guess that someone could make a custom shaft to fit the XV-02 slipper, but it'd require lathe and milling machine...

     

    • Like 1
  11. 14 hours ago, DTSCB said:

    So, are you going to try to build one?

    If someone produces a fully English parts list...

    I don't have a TT-02B, so I'm not building it. But some parts can be useful for my other projects 😁

    There's photo that shows all the parts needed. Except for shims on the top right, or PNs are visible. The YR mount is probably not necessary, if you use XV-02 0.6 spur instead of the suggested 48p one.

    I also found follow-up posts that show detailed build, modifications and parts athat were not shown in the initial post:

    - Part2

    - Part3

    - Part4

    You can use Google translate to get somewhat intelligible translation

     

    • Like 1
  12. On 6/24/2024 at 5:15 PM, nowinaminute said:

    Don't charge unattended.
    Don't over/under charge.
    Always balance charge.
    Use the correct settings.
    Use the correct charger.
    Dispose of damaged/puffed/misbehaving packs.

    To add a few:

    - Never store fully charged batteries. Use storage mode (3,8-3,85V/cell)

    - fully discharge the battery before disposal.

    • Like 1
  13. The last race resulted in DNF in the last SS due to driver's error. Good news is that the suspension mount worked as anticipated and it didn't break other parts of the chassis.

    Resize_20240627_095032_2783.thumb.jpg.bb3d8d72cc81d2a3f9fac13040c9dc3b.jpg

    Over the summer break, I'm planning some modifications. I'm waiting for delivery of #51748 parts tree to test some new ideas.. :)

    • Like 3
  14. 29 minutes ago, chris.alex said:

    I just don't understand what you mean by "doesn't engage entire teeth". In my MF01X the speed-tuned gear set fits perfectly and works flawlessly.

    d2994e7e_27a0_4359_a5e9_2b9e0cec2f89_790902584925838ca2820c08efc141f0defdc0ff.thumb.jpeg.6c1398ba15f58c3856b2b58eaf093d99.jpeg

    (Image from rctech)

    The small spur/idler engages from opposite side than in TL-01, and since speed tuned gears are narrower, the contact between teeth is quite narrow. It does work, but I'm concerned about longevity with a stronger motor, I stripped couple of stock ones back in the days with TL-01.

    The issue could be probably solved by shaving the tube part and getting narrower bearing or some insert with a smaller bearing, to get the gear closer to the motor.

    Since I already needed an extra gear to relocate the motor, I used M-05 gear set to achieve the exact same gearing as other Tamiya M-chassis. But I also designed it with wider range in mind, covering gearing of TL-01 and M-07 as well. It does not go as low as the original MF-01X, the lowest possible ratio being roughly equivalent of 18T pinion with the original gearing, but IMO that's not needed as long as it's used as an onroad/rally car.

    Compress_20240620_093636_6901.thumb.jpg.42bad1bed1572f168bf11e7911cc9404.jpg

    • Like 1
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