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ThunderDragonCy

Grasshopper 2 Ultra G - Independent Suspension All Round

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I've been slowly keeping up... the Body Post fix was brilliant!!! 👌😎👍👍

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Had a bit of time at lunch. Remembered I got a front shock tower mount for my TA02 when I got a bunch of stuff 3d printed for that. It was a just in case thing as I never designed a tower for that, but unbelievably it fits perfectly just in front of the steering aperture in the tub!

I measured up a bit and drew up a tower to replicate the shock upper pivots of the original tub. Ultra G handles really nicely, so I am not changing any suspension geometry. 

Printed out a paper outline. 

Grasshopper 2 Ultra G Carbon Front Tower

Double checking against the bodies

Grasshopper 2 Ultra G Carbon Front Tower Grasshopper 2 Ultra G Carbon Front Tower

The shocks will fit behind the tower. It will just need a small spacer and a ball nut to fix them. 

On the Grasshopper 2 although this shape clears the body, there is a lot of room so if I cut the shell slightly I decided I could add some more depth at the corners for more strength. 

Grasshopper 2 Ultra G Carbon Front Tower

I also drew up a plate that is 5mm larger than the footprint of the tower mount that I will fit under the tub to reinforce it all and prevent the fixing screws pulling through the plastic. 

The last thing I noticed was that my proof of concept linkage steering clearly works, but the 3d printed mounting plate is a bit flexy so I'll get a carbon version whilst I am at it. All the drawings went off to fibrelyte today. Hopefully Ultra G will be fighting fit before long. 

 

 

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Fibre lyte parts arrived, so I stripped things down for the installation. First thing on was the base plate:

Grasshopper 2 Ultra G

At the last minute I changed this design from a simple base plate to stop the bolts pulling through to something that included mounts for the camber link balls. I stole the idea off @Pintopower Using the tower mounting bolck as a drill guide I ran my 3.1mm drill bits through the tower and the tub.

 

Grasshopper 2 Ultra G

My measurements were a tiny bit off and I had to open out the holes to 3.5mm to make it all fit, but it's all on and good. The top centre fixing is the body mount screw. 

Grasshopper 2 Ultra G

All installed with M3 x 25 screws and nuts

Grasshopper 2 Ultra G Grasshopper 2 Ultra G

The other thing I did was replace the flexy trial 3D printed base plate for my linkage steering with a carbon part too

Grasshopper 2 Ultra G

And all back together. M3 x 8 screws through the base plate into some ball nuts for the camber links. I had to shorten them by about 4mm and the adjusters are bottomed out, so I might need to get some slightly shorter turnbuckles, but it should run:

Grasshopper 2 Ultra G Grasshopper 2 Ultra G Grasshopper 2 Ultra G

My Ultra Hornet is getting the base plate and link steering as well, but I'm going to go with the stock towers on that to start with.

 

 

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Trimmed the GH2 body to fit. Just needed to take a little square of ABS off ahead of the existing shock tower slot. Used a stanley knife and files. Super easy.

Grasshopper 2 Ultra G Grasshopper 2 Ultra G Grasshopper 2 Ultra G

The Saint Dragon body fitted with no trimming because I cut that a little big around the towers. All good to go!

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Awesome mate! Looks the biz. Did you try to calculate the steering geometry etc.? Do you have any bump steer? I have a custom set up by a previous owner on my Madcap mongrel and tweaking the tower and shocks recently seems to have left me with some bump steer:unsure:

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54 minutes ago, Kol__ said:

Awesome mate! Looks the biz. Did you try to calculate the steering geometry etc.? Do you have any bump steer? I have a custom set up by a previous owner on my Madcap mongrel and tweaking the tower and shocks recently seems to have left me with some bump steer:unsure:

I just try things out as I go along. There is a tiny bit of bump steer at full compression. I have found the bump steer is mostly caused by the steering arms not starting at the same angle as the suspension arms, so they travel through different arcs causing bump steer. It's usually fixed by adding or taking away spacers under the balls on the knuckles to get the steering arms at a better angle. That helped on my Thunder Dragon. 

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Some (unintended) work on Ultra G. I hadn't run it since fitting the carbon tower, so yesterday I took it to the park to see how it stacked against my new vintage Mid conversion, Ultra Hornet. 

The Ultras - Tamiya vintage mids

Unfortunately Ultra G wouldn't power up, which after some investigation back home turned out to be a randomly dead TBLE02S ESC. I fished that out, and decided to install the Hobbywing Justock XR10 60a ESC I used to race in my touring cars. I was going to sell it, but luckily I hadn't got around to it. Its a great ESC. Zero timing adjust for racing, but lots of other things you can tweak, plus its low resistance and lipo alarmed so a big plus over the dead tamiya ESC. After a bit of soldering it was in, and I made a new tub reinforcing strut out of bent rod to clear the fan. And a little bar across the old MSC mounts to keep the wires in one place. 

Tamiya Grasshopper 2 Ultra G

 

It all fired up perfectly so time to give it a test 

Tamiya Grasshopper 2 Ultra G

And it ran well. The steering is a little wandery, but I think that's the new camber link plate. The 38mm front turnbuckles are bottomed out, but it still has neutral to slightly positive camber. I have ordered some 32mm turnbuckles to sort it. The motor and ESC both ran pretty cool considering the grass, so it's a win all round.

It definitely doesn't put the power down as cleanly as Ultra Hornet. I suspect a combination of the open diff here vs ball diff, and these Mezzo rear tyres on Ultra G aren't as good on grass as the mini spikes on Ultra Hornet. Really looking forward to running them at the track together sometime. Here's a bit of shakeycam of today

One thing I have ordered as well is some JC Racing Wild One style wheels like Ultra Hornet. I just don't like the fussy Astute wheels as much. I am going back to Super G style flouro yellow too. 

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Super G style!

Grasshopper 2 Ultra G

 

I know they clash horribly, but I much prefer them. I think my inner 13 year old just wants a Grasshopper 2 Super G so badly! 

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Cy, that looks sweet!! 

..... This just arrived today for me! 

G6whKXj.jpeg Only thing I've decided so far is that I'm dying the Wheels Green. 

I've managed to dig in this far... jjyBrWo.jpeg

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Finally got a chance to run Ultra G and Ultra Hornet together today on some short grass near the football goal in the local park. Really interesting to compare them:

They both have similarities. The relatively short wheelbase, mid-motor and longitudinal battery give them both great front ends. Off throttle turn in is really good on both. On throttle, ultra G is quite different. You can see the wheels pattering up and down across the ground, but on this bumpy terrain you have to be careful how quickly you open the throttle. Its soft in roll, and has a completely open diff so the inside wheel spins up quite easily. On a little patch of loose dirt this is really obvious. However, overall it doesn't make it bad, just something you have to be aware of. Ultra Hornet is noticeably more settled at the rear, with the ball diff putting the power down more cleanly and the stiff arms keeping it a little more calm. I never worry about Ultra G on throttle on the track though. The high grip surface negates the open diff as the tyres always have traction, so it will be interesting to compare again when I next get some track running. Love both of these though.

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Been a while! First Tamiya Junkies meet up at Robin Hood Raceway since March. Got there for the afternoon. Mostly running inside, although the national astro track was driveable, if a little damp. 

 

20221126_121808.thumb.jpg.84a576ccb1be9cf6fe1a20149857208e.jpg

It has been said a bunch of times, but Ultra G was a complete delight. Running it back to back with Ultra Hornet actually showed Ultra G to be the better car. Faster, much more rear traction. This was quite unexpected as the ball diff in Ultra Hornet should have been great in the damp slippy conditions, but the rear suspension on that simply didn't offer as much grip on throttle. At least with current setup. 

Anyway, I ran Ultra G outside for a good while, with the Grasshopper 2 and Saint Dragon shells. Had a bit of an altercation with trackside furniture off a jump, but all seemed OK. I then ran laps and laps inside and it was just great. When the battery died I took the shell off and spotted a crack, which was actually terminal.... 

20221126_150902.thumb.jpg.9dc93d3314727d5b33ab22eae880d709.jpg

Despite carbon reinforcement, after 4 years the tub in the thinnest part gave up and broke.

So, new tub for Ultra G, and some thought on some kind of bridging pieces or reinforcement for this area. 

To be continued.... 

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New tub day. Was a big apprehensive about this, because its so great and I am worried about screwing it up in the change, but needs must. 

20221203_163155

Had to tweak the lengths of the reinforcing bars as the old tub must have got warped over time. 

I haven't done a step by step as you can see it in the rest of the thread. Nice thing about having a fresh tub is fresh threads in everything, so some of the work around long bolts and nuts have been replaced by shorter screws in the plastic. 

Couple of things though: Both this and Ultra Hornet got some shorty battery plug holes in their battery trays so I can run the shorty towards the rear 

20221203_172006

I also made a slightly smaller, neater cut out for the steering as I now have a dremmel, and I cut the towers off just flush with the top of the carbon tower. I wanted to leave some stiffness and reinforcement for the tub in this demonstrably weak area. 

20221203_172013

I have ordered some longer M3 rod to see if I can run two reinforcing rods from the top of the front tower mount to the rear of the tub. We will see how that goes. 

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Ran at Tamiya Junkies today. Indoor, on high grip flat astro. Was a lovely meet. Loads of people running all sorts of cars.

FB_IMG_1673729952204.thumb.jpg.563a9f9e828b4052341dd47ddb6be1ef.jpgFB_IMG_1673729974978.thumb.jpg.15672589fb97842c43368357b0885f9b.jpgFB_IMG_1673729990730.thumb.jpg.3666e05d49d7abc4e7ba0f54f9148d07.jpg

It was the first outing since I re-tubbed it, and apart from a tweak to the steering it was mint. Thank goodness! It was quite tricky once the track cleaned up because there was so much grip. The odd traction roll! Ran the Saint Dragon body too, which did help a little. The number of rolls did see off one of the body mounts first day of running! Looks like I need the body mount mod above already. 

Another lovely thing was one of my mates at the meet has built an Ultra G conversion of a Grasshopper 1. It needed a bit more doing than on the GH2, with a custom front and rear shock towers. It is otherwise this conversion with my 3d printed parts and it was ace! Ran so nice straight out of the box, and I had a drive and helped him dial in the steering a little. So excited someone else had finally built one! Bit of video of it running. 

https://www.facebook.com/groups/780798785431932/permalink/2336388646539597/

 

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10 hours ago, ruebiracer said:

So cool @ThunderDragonCy !

This would be a Grasshopper for me!:wub:

Do you have a link to the video outside FB maybe?:)

I will get a video on YouTube later. The GH body is smaller and tighter fitting that the GH2 so took a bit more doing than my Ultra G. Graham made custom lower rear tower (although the Terra Scorcher / Fire Dragon tower might fit) to clear the rear of the body, and a front tower different to mine to avoid cutting the shell and because you can't bolt up cva mini shocks to the GH towers. Some 55mm super mini shocks might work though. 

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Wow! Didn´t know, that Graham is @graemevw!:lol: The old suspects! 

Great work from both of you, that thing looks really subtle and planted! Must be loads of fun!

I´ve too many projects running at the moment, but this concept will stay on my list for sure!

So cool, with the Vintage Grasshopper looks and sleeper tech !:ph34r:

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32 minutes ago, ruebiracer said:

Wow! Didn´t know, that Graham is @graemevw!:lol: The old suspects! 

Great work from both of you, that thing looks really subtle and planted! Must be loads of fun!

I´ve too many projects running at the moment, but this concept will stay on my list for sure!

So cool, with the Vintage Grasshopper looks and sleeper tech !:ph34r:

Yeah, same old faces 😂

Been playing with non tamiya stuff for a while so not been on here much recently.

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With Ultra Hornet looking so slick, I decided it was time properly finish off Ultra G and to figure out the tricky geometry of some proper transmission mounting plates. 

With the help of @wtcc5 I got a plate laid out, and designed some spacers so that eventually the plate could be made in carbon fibre.

20230406_203043 20230406_203057

There is a recessed boss at the top where the plate fits over the original top shock mount boss. There is a large spacer for the rear transmission mount, and a 2mm washer behind the other transmission mount. The two holes lining up with the tub are 2.5mm so you run a 2.5mm drill through them then use self tapping tamiya screws to mount it. Looks pretty slick, right? 

Left side through a little spanner in the works! 

20230406_203401

Antenna mount. Doh! Used a Stanley knife and a file to smooth it down

20230406_203905

The plate hole doesn't line up with the antenna mount hole, so I am going to measure that best I can and move the plate hole to use that. 

These aren't really meant to be strong enough for long term use. They were 3d printed with some other bits to test fit, but now they are on I will run them and see how it goes. Finally looks like I have a nice piece for anyone else wanting to Ultra their G. 

 

 

 

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Took Ultra G for a run out in the park with its brother from another mother

20230408_172945

Although not conclusive as there were no big hits and no jumps, the side plates held up fine. Only change was flipping the aerial mount around to stop it moving

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When I got home, I swapped out my steering linkage to the right hand version I have on Ultra Hornet. This puts the steering drag link longitudinal, not across the chassis which is where it was. That gets in the way of battery leads and plugs on the shorty lipos I use. 

Seeing as I had the steering to bits, I pulled the front body mount off and trial fitted the scrap Hornet shell I got. With the inline front body mount it would fit. 

20230408_184313 20230408_184320

 The GH2 tub is a tiny bit wider in the centre, but it would work. This is much easier than converting a hornet/GH1 tub too. 

 

 

 

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