Hot Shot 2 vs Terra Scorcher

[Jonathon Gillham 4708]

1 hour ago, StueyS said:

I have two Terra Scorcher 2020 kits I bought in winter 2021 that have split the front wishbones from light contact on the front wheels. I managed to get some older arms second hand which have been fine so far, and some nylon 3d printed arms which are also working out fine. I think there has been a batch of bad arms, or a possible change of material. Quite how you might tell I don't know!

I'm hoping its a bad batch and once they're done we get some decent ones.  If its a change to material and this is how fragile they are then it basically means these cars are shelfers only.  Just ordered 3 new sets, hopefully that will last through summer!

[Saito2 8309]

1 hour ago, Jonathon Gillham said:

I'm hoping its a bad batch and once they're done we get some decent ones.  If its a change to material and this is how fragile they are then it basically means these cars are shelfers only.

Me too. I'm sure the base plastic is still the same, polyamide/nylon I believe, but perhaps the formulation is off somehow (?). It would seem it had something to do with the mold parting line, but looking at the parts tree, I noticed that 2 of the 3 mold gates dump right into those common split points as well. The gates are small so there's not much in the way of gate vestige (not really an issue I've seen as the material cuts like butter). Perhaps an improper fill speed this time around? Its harder to see if there's any blushing or hints at other issues since the arms are blue and not black. This is something distressing as I know what happens in my line of work when there are product problems out in the field. The extent of investigation, determination of trending, back tracing and finally quarantining/NCR reports leading to approved deviations and finally a re-engineered part is tedious but none of this happens in the RC car world. 

[Kowalski86 4780]

On 11/23/2023 at 6:29 PM, Saito2 said:

This is something distressing as I know what happens in my line of work when there are product problems out in the field. The extent of investigation, determination of trending, back tracing and finally quarantining/NCR reports leading to approved deviations and finally a re-engineered part is tedious but none of this happens in the RC car world. 

It'd be nice if RC cars were held to the same standards as a common appliance, especially for the price that they cost.

This really does stink to hear about though, the Thunderdragon/Terra Scorcher was one of the few re-res that I've been considering, to the point where I was close to buying a brand new kit. I'll wait and see if the problem persists.

Tamiya is the only big RC company that I'm aware of, that gets away with some fairly serious faults in their kits.

[Pizza Frog 772]

Does the issue effect the blue arms on the Thundershot/Dragon chassis as well? D1 and/or D2?

Jazrider sells aluminum replacement arms for that chassis.  Both upper and lower arms

https://www.jazrider.com/tamiya-rc-thunder-shot-fire-dragon-parts-c-1298_3778_5568.html

 

[Saito2 8309]

5 hours ago, Pizza Frog said:

Does the issue effect the blue arms on the Thundershot/Dragon chassis as well?

I would presume so, as they've all been brought back around the same timeframe. However, it is possible the issue is more prevalent in the Terra Scorcher vs the T-Shot/Dragon cars due to the Scorcher's adjustable upper links not offering any added support. Those arms are very twisty. Using the solid upper arms the Thundershot /Dragon cars have might alleviate the problem (IIRC, these additional solid upper arms come with the Terra Scorcher kit anyway as extras on the arm tree). I should get another set of lower arms and do some testing with the solid uppers.

[Twinfan 2314]

Mine was a rear lower arm on a Fire Dragon that went, which has solid upper arms, so those cars are certainly not immune.

It sounds like it's an issue, if it is an issue, with the most recent re-res from 2020 onwards.

[Saito2 8309]

23 minutes ago, Twinfan said:

Mine was a rear lower arm on a Fire Dragon that went, which has solid upper arms, so those cars are certainly not immune.

Bummer. 

[StueyS 49]

The 3d printed heavy duty arms have more material around the inner hinge pins so hopefully a bit more sturdy. With the postage from Shapeways they are not cheap. Not racing the car for me is unacceptable.

[StueyS 49]

https://www.shapeways.com/product/VS627YQB9/hd-thundershot-arms-x4-tamiya-terra-scorcher-d1?optionId=66766329

 

[Saito2 8309]

Took my damaged arm out for quick look under the magnifier. The split is not at the mold parting line, but rather below it. No signs of blushing but some whitish discoloration in other areas from being pulled and bent out of its hinge pin. I've seen another member span the gap between the front and rear inner pivot points with metal tubing. Initial reaction was that it would cause impact loads to transfer from the front mounting point to the rear, i.e. not good. Upon further thought, would a tightly (though not binding) fitted piece of tubing, perhaps with washers on either end (to add support/surface area and prevent the tubing from cutting into the soft arm plastic), help discourage the arm from pulling out on impact? As it stands now the front pivot portion of the arm would need to pull outward (splitting the plastic), but also flex backward. The brace tubing would minimally prevent the backward flex of the portion of the arm. The material may be so soft that it could squirm out regardless, but it might be worth a try.

[Pizza Frog 772]

1 hour ago, Saito2 said:

Took my damaged arm out for quick look under the magnifier. The split is not at the mold parting line, but rather below it. No signs of blushing but some whitish discoloration in other areas from being pulled and bent out of its hinge pin. I've seen another member span the gap between the front and rear inner pivot points with metal tubing. Initial reaction was that it would cause impact loads to transfer from the front mounting point to the rear, i.e. not good. Upon further thought, would a tightly (though not binding) fitted piece of tubing, perhaps with washers on either end (to add support/surface area and prevent the tubing from cutting into the soft arm plastic), help discourage the arm from pulling out on impact? As it stands now the front pivot portion of the arm would need to pull outward (splitting the plastic), but also flex backward. The brace tubing would minimally prevent the backward flex of the portion of the arm. The material may be so soft that it could squirm out regardless, but it might be worth a try.

I like the idea of a homemade fix, Maybe it's possible to glue or epoxy a small metal or plastic washer to the inside surface 
 
(hope I have the right area where the split is likely to occur)

[Saito2 8309]

39 minutes ago, Pizza Frog said:

Maybe it's possible to glue or epoxy a small metal or plastic washer to the inside surface 

Yes! I was pondering that too after I posted about the tube bracing.  A washer glued to each inner end, like you have pictured and then brass tubing run between them, taking up the gap. I know someone else has done and/or suggested this. As long as the glue is suitable for nylon, it should help.

 

As a total aside, I wonder if a T-shot buggy could keep pace with an Optima Mid?

[Tamiyastef 3043]

@Pizza Frog I hope it's OK to reuse your picture

I was thinking to drill a small hole where the red dot is and use a small ziptie 

And even file or grind out a small 'gap' where the green line is ( going all the way round to the other side of the hole) to get enough clearance for the ziptie.

[Pizza Frog 772]

Just now, Tamiyastef said:

@Pizza Frog I hope it's OK to reuse your picture

I was thinking to drill a small hole where the red dot is and use a small ziptie 

And even file or grind out a small 'gap' where the green line is ( going all the way round to the other side of the hole) to get enough clearance for the ziptie.

Yes of course. 

I was thinking about a zip tie too, or nylon fishing line going around and anchored by a screw on one of the four damper mount holes for a crude fix to stop sideways movement.

 

[Tamiyastef 3043]

Despite the probable weak arm problem I still went for this:

I'm sorry @Re-Bugged but temptation was too big seeing this in my LHS. The smell of new Tamiya tires is just irresistible 🙃

I thought a 1060...

But it comes with a 1040... A Torque Tuned shouldn't be a problem on 2S I hope. 

The 600 is new to tweak the dampers.

[Saito2 8309]

43 minutes ago, Tamiyastef said:

I was thinking to drill a small hole where the red dot is and use a small ziptie 

Interesting how we're all thinking along the same lines. I was also considering something similar only using a twist of mechanics wire. It was a trick I saw @kontemax use to hold his old splitting Boomerang parts together.

[Saito2 8309]

Here's the picture I was thinking of with the tubing between the arms:

It conceivably does transfer more impact loads from one mounting tab to the other, but perhaps the arm's overall flexibility would prevent that occurrence from being terminal. I was just thinking the tubing would make it tougher for the arm to pull out by preventing one of the arm's bending paths in the case of an impact.

[Pizza Frog 772]

1 hour ago, Saito2 said:

Here's the picture I was thinking of with the tubing between the arms:

It conceivably does transfer more impact loads from one mounting tab to the other, but perhaps the arm's overall flexibility would prevent that occurrence from being terminal. I was just thinking the tubing would make it tougher for the arm to pull out by preventing one of the arm's bending paths in the case of an impact.

I see what you mean with the tubes transferring the load of impact, that looks really good.

Is the left arm the one with the split?  It looks like it's missing a chunk of plastic on the top mount, I was hoping that any splits would be reparable.  

[Re-Bugged 11948]

No apology necessary @Tamiyastef, all good 👍🏻 

Very happy to see you using a local business they are a case of use them or loose them these day’s. The feeling of perusing a physical shop and walking out with a nice kit on the same day never gets old 😄

Enjoy it (and the Tamico racing) mate, a nice winter project for sure.

 

[Saito2 8309]

12 minutes ago, Pizza Frog said:

Is the left arm the one with the split?

I don't know. Its not my car, but another member's. I didn't want to take credit for the idea but thought it might be useful for our problem...possibly.

[Andreas W 3016]

6 hours ago, Tamiyastef said:

Despite the probable weak arm problem I still went for this:

I'm sorry @Re-Bugged but temptation was too big seeing this in my LHS. The smell of new Tamiya tires is just irresistible 🙃

I thought a 1060...

But it comes with a 1040... A Torque Tuned shouldn't be a problem on 2S I hope. 

The 600 is new to tweak the dampers.

Congrats with the purchase. You will be happy with it. 

 

Now get the Xtraspeed alu A5 and. B8 parts and suspension shafts and it is (relatively) bomb proof. Looking forward to hearing about your racing experience in 2024.

 

BTW have I done exactly the same tubing mod as on the pics above on my Thunder Dragon.  Knock on wood; nothing has broke on it yet. 

[Tamiyastef 3043]

15 hours ago, Andreas W said:

the Xtraspeed alu A5 and. B8 parts and suspension shafts

Those have been ordered 

15 hours ago, Andreas W said:

hearing about your racing experience in 2024

Well I think I'll start a seperate topic about my "Tamico Off road cup 2024 adventure" from the moment I start building/preparing/working on the cars I'll be driving. Not sure where to put it? General Discussions, RC Racing Talk or Meetings & Events?   

[Frog Jumper 4254]

You’ll enjoy the TS.  Its a great car.

[Kowalski86 4780]

On 11/24/2023 at 5:39 PM, Tamiyastef said:

I thought a 1060...

But it comes with a 1040... A Torque Tuned shouldn't be a problem on 2S I hope. 

Strange, I had assumed those were discontinued, still better than a TBLE02 though.

Let us know how your arms hold up, I'm hoping that it's just a small fluke.

[Andreas W 3016]

12 hours ago, Tamiyastef said:

Those have been ordered 

Well I think I'll start a seperate topic about my "Tamico Off road cup 2024 adventure" from the moment I start building/preparing/working on the cars I'll be driving. Not sure where to put it? General Discussions, RC Racing Talk or Meetings & Events?   

Looking forward to that thread. I would put it in the race categorie. It is real racing after all . 

 

I would now keep an eye open for a good offer on a parts car, like I mentioned. Here in Norway the prize for a Terra has dropped 84€. The Thunder Dragon and Fire Dragon are the cheapest of course. Then you have all critical parts at hand and risk zero downtime. The no ESC versions are even cheaper.