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ThunderDragonCy

Hotshot 2 Not Blockhead

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I wanted a winter build, and I don't have a member of the hotshot series. I love the look of all of this series, but they all seem to have major drawbacks compared to the later Thundershot series - which I know and love. 

I have built a Boomerwig (boomerang with bigwig front suspension). Was nice, but the sliding steering was rubbish so I sold it. 

The Hotshot2 always seemed a bit of a sweet spot. Amazing lines, but tididd up and improved over the HS1. Same as a lot of you, I was pretty disappointed with the Blockhead HS2 rere. so this is my Hotshot 2 "done properly". First few bits arrived. 

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Repro hotshot 2 shell from penguin. Hotshot front stabiliser stays, and hotshot2/boomerang rear arms. A rere Super Hotshot kit should arrive tomorrow. 

Plan is to sell off the gold wheels and kit tyres, and the supershot suspension kit, and the body. 

I am going body art on this. Got mci sending the decals, and the body will be black, and I am keeping the front monoshock. 

Got some red highlighted yeah racing big bore shocks coming, and m05 steering set to upgrade the steering. I need to work out some carbon bits for the suspension mountings, and maybe some 3d printed bits if needed. Should be fun!

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Nice 👌🏻.
I’m sure you won’t have any problems selling the wheels as it’s got to be the No1 hop up for a red Hot Shot 😉

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Based on your previous threads this is going to be an interesting build. You are probably on the go by the time I am back from work, if the SH turns up today. 

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Nice! The Hotshot II was my first RC, so it's on the cards some day for me to recreate. The Blockhead version certainly doesn't fulfill that requirement!😤

Good luck with the build, look forward to seeing the progress and updates🙂👍

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What are you doing for rear uprights ? (The super hotshot rear uprights won't fit the boomerang arms and red rear uprights are only available as vintage items, or are you going to use re-re boomerang bits and dye / paint them)

 

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1 hour ago, MadInventor said:

What are you doing for rear uprights ? (The super hotshot rear uprights won't fit the boomerang arms and red rear uprights are only available as vintage items, or are you going to use re-re boomerang bits and dye / paint them)

 

That's possibly where the 3d printing comes in. I want to try and keep the red knuckles front and rear, although I also want to try and make front universals work so the front ones might not survive. At the rear, I am thinking some camber links to make the kit super hotshot uprights work, which is where some 3d printed bits might come in. 

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Modelsport delivery! 

20221223_142704

 

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Supershot kit, JC concepts 2.2" chrome wheels (neatly went kit correct white, but couldn't resist these), cheap etronix 15 turn brushed, 1060 esc and 13t pinion as a first go on power system. Schumacher wide cut stagger ribs for front, got some mini spikes spare for the rear. Tamiya black for the body. 

Won't start building for a few days because of Christmas family stuff, but glad it's here. Just got the rcmart order to wait for. 

 

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That's another piece of quintessential Tamiya for me. All those models have a really "grrrrr" thing about them for me and some crucial realism was lost after them. Shiny silver wheels will top it off. Merry Christmas Cy! 

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23 hours ago, ThunderDragonCy said:

That's possibly where the 3d printing comes in. I want to try and keep the red knuckles front and rear, although I also want to try and make front universals work so the front ones might not survive. At the rear, I am thinking some camber links to make the kit super hotshot uprights work, which is where some 3d printed bits might come in. 

I believe Boomerang rear uprights is the correct solution.
Paint them with pink Tamiya primer and then with red.
You will need the rear suspension tower but you can do it with carbon fiber plate.
The lower battery door will be a problem.
Red shocks are also a problem.
Why didn't you buy a vintage Hot Shot 2?

Max

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@kontemax I am not looking to produce an exact copy of a Hotshot2, just something like it with the mono shock and cool body. I am getting red highlighted yeah racing shocks, and I am not bothered by the battery door. I will be using shorty lipos, so that area might be modified anyway. 

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1 hour ago, ThunderDragonCy said:

@kontemax I am not looking to produce an exact copy of a Hotshot2, just something like it with the mono shock and cool body. I am getting red highlighted yeah racing shocks, and I am not bothered by the battery door. I will be using shorty lipos, so that area might be modified anyway. 

Square Lipos (Certainly 2S Zippy hardcase Lipos) will fit straight into the hotshot battery tray with no mods required (Maybe the 8.4V battery holders are needed, I can't remember if I've got them fitted to my car or not)

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Ah, another very cool project from @ThunderDragonCy! Can´t wait for the build!! HS 2 is also my favorite model of the series. Was tempted by it back then, but then there was the Terra Scorcher, too, which I found nice. In the end, my first 4WD Tamiya Buggy was the Vanquish. But this HS2 will be a stunner, I´m sure! Can´t wait to see all the planned performance tweaks. The Yeah Racing shocks look really nice! Maybe you can report, how they build up and the feeling.

Have fun, 

Matthias

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Started the build. Didn't do much as weather was OK so went for a ride this morning. 

First thing was to build the front trans and arms and see what driveshaft will work. This is a tamiya DF02 70mm universal

Apologies for sound. I had to hold the phone in my teeth. Definitely binds. That is the suspension being forced to move down as I rotate the wheel. 

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Did another couple of tests on the front suspension. Firstly I installed the stock driveshafts. These still bind like the universal above, but with the arms moved up further. 

Having done some searching I found a thread on here about someone fitting the rear driveshafts out of a DB01 with some success. These have a 64mm swingshaft, which in theory should make them too short. However, all the TRFs used a very long wheel axle for the pin drive wheels. The thread explained that he put an 850 bushing on the axle before installing - effectively a 2.5mm thick spacer - and the spacing worked to install a regular hex on the outside as usual. 

I have a TRF211 with the same rear suspension, and as it happens, the fancy double cardan joint too. I took one out, put the 850 bushing on, and installed on the hotshot. Works perfectly! Huge up travel, no binding. The double cardan joint does catch a bit on the knuckle at high steering angles, but it would probably work. 

The only downside is that spacing the axle lie this puts the pivot of the driveshaft away from the kingpin axis which isn't ideal. So, given the swingshaft is 64mm, and I have a 2.5mn spacer, I either need to find another brand universal which is 66.5 or 67mm with a regular wheel axle, or a DB01 rear universal shaft set so I can get my TRF211 running and use the DCJ in the Hotshot. 

Anyone got any suggestions for other band 67mm Universals? 

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Bit more today. Loose assembled the rear end with Hotshot rear uprights and boomerang arms

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Without the rearward offset of the HS2 and Boomerang rear knuckles, the rear Hotshot knuckles sit pretty much in line with the front of arm shock mounting on the arms. 

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Measured the offset of the knuckle top to the gearbox boss at 8mm

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I spent an hour or so modelling up an arm that would solve the problem, moving the knuckle rearward a few mm, and putting 3 deg toe in. 

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Here is the boomerang arm over the top

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On reflection I am not sure about this. The SLS Nylon printed arms I have on my FF01 have been solid and stood up to racing, but I have broken a few parts on buggies in the same material. That said, I seem to have OK reliability on rear knuckles I have done. Don't know. For now I have ordered some more ball nuts to see if camber links for top arms will clear everything. Or I just ditch the HS2 front shock mount and put the Super Hotshot setup on. That's definitely easiest, and I am mainly doing this for the HS2 body and cool front monoshock. Be interested to know what you guys think about this? 

Other thing I did was fit up the front end to work out the front suspension. 

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I measured up the pivot centres on the hotshot front arms at full droop and did a dummy cad model of them so I could get the starting geonetry. The Yeah Racing 80mm shock has a long 25mm stroke, so I needed to work out how long the extensions need to be for 80mm at full droop and 55mm at full compression. What I needed to work out what full compression is. I fitted the under side plates and set it on my desk, then put some lego under the wheels. This means the shock won't bottom out until after the chassis does. 

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I measured the existing shock mount position like this and worked out some extension plates that would push the shock the correct amount. I will get these made out of 2mm carbon, but need to hold off until I figure out the rear end as I need a shock mount for whatever I decide to do there if I stick with the front mounted HS2 approach. 

 

 

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On 12/30/2022 at 9:31 PM, ThunderDragonCy said:

 

 

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Complicated solution for a simple problem.
Use red painted rear Boomerang knuckles or try to find some used red ones.
If you move the knuckles back your will increase the wheelbase and change the balance of the model making it over steerer.


Max

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OK, some sleep and more thought and the obvious solution was staring me in the face, as usual

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Put the turnbuckles I bought for it on the back, and everything clears fine. Slight hiccup is that I can't feed an m3x25 screw into the gearbox end from the inboard side to secure the inner ball nut, so I need to buy some ball collars so I can through bolt it. Other than that, I think this is back on for a front mounted shock. 

20221231_105218

 

 

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And a bit more. I wanted to see how the M05 steering might go together, and ended up fitting it! I thought I was going to need a carbon mounting plate, but the DB01 steering posts I got to help the installation stood the arms off the tub about 3mm. With a lot of wiggling of things and jamming my finger through the radio access hatch in the top of the tub I wasn't sure there would be height for a 2mm plate as well. 

I measured up the links and worked out I needed 38mm spacing on the steering pivots, and if I pushed them slightly forward of the bumper mounting holes, the heads of any bolts would sit in the bumper moulding. So, after cutting the front bulkhead out with my dremmel, I started marking out. 

Tamiya Hotshot M05 Steering Mod

This was all done using my calipers, a steel rule and Stanley knife to score. I measured a lot and checked a lot! I made the impressions for the drill with a crosshead screwdriver. Then I drilled 1.5mm pilot holes. I would advise using 2 or 2.5 for this as the 1.5 is quite flexy and wandered a bit. I finished off with my 3mm reamer. 

Tamiya Hotshot M05 Steering Mod

The DB01 posts in place with m3x20 screws from the kit. Cap head hex screws are too tall to fit under the bumper. These JIS screws don't have the biggest heads so I have ordered some flanged button head screws for the final fix. 

Tamiya Hotshot M05 Steering Mod

The steering arms juuuuust fit inside those vertical bosses in the tub. Some nyloc nuts to hold them in place. Only slight subtlety is that I flipped the steering wiper. This has two advantages: Firstly it moves the centre of the bar inboard so it is a bit further from the gear case, and secondly it moves the second holes in the ends to the front side, so a first lose fit suggests I won't need to cut away any more of the tub to make this work. Fingers crossed. 

I had a play with the layout of the radio box. At the moment it looks like the best option is to drill some new servo mount holes to allow me to install the low profile servo with back face hard up against the right side of the tub. This will put the servo arm roughly in line with the steering arm. I am planning to use one of the extended ball connectors that are provided for the original steering knuckles on the M05 steering arm. This will lift the steering drag link up and allow me to install the receiver just behind the steering set.

At the moment I think this will leave me room to install the 1060 esc stuck to the sidewall opposite the servo vertically.

I need to learn how to solder servo wires as I seem to have cut the plug off at some point. The wire could do with being much shorter, but I have no idea about the plug itself! 

So, more to fiddle with, but quite pleased with how quickly this came together. 

 

 

 

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TDC, loving your work. Keep posting for the rest of us. 

 

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Lose fitted the chassis together with a bit of the roll cage to try and figure out rear shock mounts 

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Couple of things became obvious, and we're confirmed with a looked at the Hotshot 2 manual again. Firstly, I don't have the centre shock mount boss like the Hotshot2, Boomerang and Bigwig have. I just have the flat plate for the rear sway bar mounting. So, a front mounted shock mount becomes difficult again. 

The other thing that came out of this is that unlike the Bigwig and Boomerang, which have a tall, fairly narrow shock mount for CVA Long shocks, the Hotshot2 has a shorter, wider mount that threads through the roll cage and uses short (80 ish mm) shocks. Given I have already bought 100mm rear shocks, this also presents a problem. 

For the moment, I am giving in and using the Super Hotshot set up. It's all here, I don't have to spend any more money, and it's designed for long shocks. 

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Interestingly, using the original hotshot arms with the upper arm tabs which drive the linkage on the orignal, these act as a droop stop. The boomerang rear arms don't have these and can move as much as they like. 

Quick dry fit of the shock shows that on the droop stop the shock is a few mm too long. I had to compress it a little to get the screw into the shock mount. However, despite this, full up travel to bottom out of the shock is possible without driveshaft binding, which is great. I need to dis-assemble the shocks and grease them and fill with oil (they are supplied assembled dry), so I will pop 1 or 2 o rings inside to make fit perfectly for completing the build. 

20230101_172951

 

 

 

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I am sending the servo off to a club mate to get the wire shortened and a new plug put on, so I wanted to get the radio box arrangement sorted. Measure twice, cut once and all that. I used a bit of double sided tape to stick everything down. This is what I ended up with

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The servo posts will need some new holes drilling in the bottom of the tub. The esc lead will route in that loop to avoid things, but I will stick it down with some tape for the final install. 

Not sure about the power switch. It won't reach the switch mount in the top tub, and the holes are spaced wrong anyway. Got half a thought to drill some holes in front of the radio access hatch to mount it there, but that is for later in the build. 

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Hopefully the ariel will route without touching the prop shaft. 

As this was all together I put the rest of the steering together to check it. This is with the ball screw mounted on top of the steering wiper inboard, and a ball screw on the underside of the knuckle, but it's just a standard one, not the large offset version from the kit. Seems to work OK. 

Also made a front anti roll bar. I had some 1.8mm piano wire in the spares box, which is a little thinner than the kit bars which are 2mm. I had the fancy TRF dropper links leftover from making some links for one of my touring cars, so seemed rude not to use them! 

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I have never made a bar before, but it was easy enough, just bending with my hands using the pliers to hold the bend spot. 

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I also fitted the rear bar seeing as I have it, using the red turnbuckles I had spare now I am not making the top arms camber links

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No idea how it will handle with these, but it's an option to get it running nice, and wash enough to take off. The rear bar on my Thunder Dragon never seemed to help any. We'll see. 

 

 

 

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