Grasshopper 2 Ultra G - Independent Suspension All Round

[Yalson 514]

I realise this might be a little late now, but I was reading the TC Top Speed runs thread earlier and saw @stew_mac's ultra-low speed run Hornet. He had some pretty unusual lengthened lower gearbox mounts on there to help it sit lower and knowing the issues you have had with those on this build I thought you might be interested.

[ThunderDragonCy 7881]

58 minutes ago, Yalson said:

I realise this might be a little late now, but I was reading the TC Top Speed runs thread earlier and saw @stew_mac's ultra-low speed run Hornet. He had some pretty unusual lengthened lower gearbox mounts on there to help it sit lower and knowing the issues you have had with those on this build I thought you might be interested.

Cheers. I'll have a look for that but the Rising Fighter parts I ended up using gave me the clearance I needed. 

[Yalson 514]

Ah, well if you've found a solution then no worries. I would recommend having a look, though, as he has turned this Hornet into what I can only describe as a missile.

[ThunderDragonCy 7881]

Wow! I haven't updated this thread for over a year. I've continued to run Ultra G at the Tamiya Junkies track days, and it's continued to be brilliant. I cracked the rear Super G neon wheels last year on track, but a local pro had given away a load of pin drive rear wheels with ballistic buggy spikes glued to them. One of the sets was neon yellow, so I converted Ultra G to pin drive. It was pretty easy. You need part number 9808153 for the axles, then grab 4 of those 850 bronze bushings you have lying around from kits you have put proper bearings in. Pop the outer 1150 bearings out of the rear uprights, put an 850 bushing in there, pop the bearing back in. This spaces the inner bearing races and allows you to clamp down on them without them binding. Push the axle through, add the second 850 bushing on the outside of the bearing, pop a drive pin through, install the wheel. Should clamp up nice and tight and spin freely with no play at all. 

Last Saturday I also finally saw off the Super G fronts, with one cracking due to a cartwheel off a jump. After a bit of searching, I have found these JC Racing wheels which they are making in 2.2" size, pepperpot style and a bunch of colours for the Kyosho Rereleases. I was thinking I would need to do some kind of hex conversion of an Optima set, but brilliantly when I went looking for them I found THESE!

Ultima bearing fit wheels. They come as a set with matching 12mm hex rears, but they aren't fitted. You can see my Losi pin drive rears up there. But back to the fronts. The Ultima uses 840 bearings on a 4mm axle, so I've had to take a punt and fit 850 bearings for the 5mm tamiya axle. They are very small, but if they get wrecked quickly I'll have to drill them out and fit flanged bearings in a bigger size. I needed to fit 4 of the Schumacher 5x7.0.4 shims behind each wheel and they work great. Can't wait to run them, but for now, if you have some Super G love, check out these JC Racing wheels. They're lovely!

[ThunderDragonCy 7881]

An update. Firstly the diddy bearings in the wheels did just fine and ran for ptobably 30 minutes total at the track last saturday. As a result of quite a tight layout (instigated by me. I have been racing touring cars indoors too much!) the front end seemed a bit soft and the inside rear was lifting a bit. I put some trf red springs on and it was much better. Going to see about a few more setup changes if i get a chance to run anywhere anytime soon. 

And so to the bigger news. I fancied a lexan shell to have as an option to see how lower weight would help handling. I love the Coro Coro series, and plumped for a Saint Dragon via @Baddon brilliantly organised group buy. I figured all Coro Coros fit all tub style chassis, having seen quite a few Hornet based Super Dragons. Despite GH2 not being on the list of cut advice options in the original manual, i thought it would go easily. It didn't! It's a bit gappy at the front as the shell is a bit narrow for the tub, but otherwise it goes ok. You need to do hit and hope shock tower cuts. And of course, never box art...

Paint went on lovely and shell trimmed up easily enough. The window mask is singly THE most difficult mask i have ecer applied. So 3 dimensional. Got it ok in the end, but maybe that soap spray sliding technique i haven't tried would work better? 

Was a bit disappointed with the washy neon yellow decals from MCI. I wanted them to match the flouro wheels. Also, with a bold base colour, the big block graphics seemed a bit much (top) , so i removed the top set (lower). 

Fitted up. I can see me trying another colour on the decals

I even remembered i had a matching driver in my old Grasshopper2 shell that i used to run on my DT03. Looking forward to running it and seeing how she handles! 

 

[ALEXKYRIAK 1046]

Simply awesome. Love the oldschool-ness and amazing paint job. Inspiring stuff sir.  

[ThunderDragonCy 7881]

17 minutes ago, ALEXKYRIAK said:

Simply awesome. Love the oldschool-ness and amazing paint job. Inspiring stuff sir.  

Thanks dude! 

[Carmine A 2046]

GOT to rehash this.... 

I am SO BUILDING THIS!! 😁

[ThunderDragonCy 7881]

Been running a makeshift track at the park the last week or so with Ultra G and my Thunder Dragon TRF. Ultra G has mostly been its usual brilliant self, but on my first run i was definitely having trouble with rear grip and the wheels coming up. A few months back i installed the wider Terra Scorcher rear shock tower, which neccessitated reducing the shock length down to 82mm by installing some short avante length piston rods i had spare from my boomerwig build. To get this setup working - and also guided by a slightly more touring car focused setup guide which said turn in oversteer can be helped with less rear droop - i ran this setup with only about 5mm droop, but it's also a fair approximation of the terra scorcher and fire dragon setup as original cva short shocks are only 80mm long. After a bit of chat with @Mad Ax i realised off road buggies need droop to keep the wheels on the ground. Lack of droop just off loads the tyres. I realised that the best setup i had run on this and on my thunder dragon prior to the trf suspension was the previous setup, which is this

Original narrow thundershot/dragon shock tower, using the top mounting position. The shocks have their original shafts back in and long eyelets and are 95mm long and it's spot on. Lots of droop, lots of travel, lots of grip! I have the gold medium springs from the DF03 set on there. If you have a thundershot chassis car i highly recommend switching to longer shocks and this setup. I have tested so many permutations of this suspension on various buggies and this is the best. 

At thefront i decided to address the flexy shock towers with a simple brace made of spare cva eyelets, ball nuts replacing regular nuts hold the shock brackets on and some m3 threaded rod. Not sure if i could feel a difference driving, but it feels way more solid 

Finally, when i was driving the Grasshopper2 shell the other day it did occur to me that the heavy plastic shell might be hampering things a little as i am now trying to be a bit more precise around my little track. I also have half an eye on racing Ultra G at a vintage event later in the year if it happens. So, with that in mind i fitted the Saint Dragon shell i did for it and gave it a run last night. What. A. Difference! 

Running this shell and one of my shorty batteries i probably saved 300 grams and boy did it show. Its always been a great car to drive, but my goodness, like this it's a proper weapon! So, so good to drive. And fast! Ido love the GH2 shell, but the Saint Dragon is definitely getting fitted for track outings. Now more than ever, i would encourage anyone to build one of these. It's so good i have to share the love! Shall i do a full parts list for the conversion? I am not sure i ever have. 

Anyway, Ultra G continues to be surprisingly brilliant for a ragtag bunch of vintage bits. Plus ca change, plus ca meme chose! 

 

 

[Carmine A 2046]

PLEASE do a parts list!!! 😁  I've been as impressed with this as you are, and should be. 

The Front Shock Brace is definitely a great idea, because the Tub frequently cracks at the base of the Towers! 

[ThunderDragonCy 7881]

Parts list then. Here goes:

Essentials:

Grasshopper 2 or Rising Fighter kit. If you don't have a preference, Rising Fighter has more of the correct parts, plus it has hex rear wheels so you can use the kit wheels if you want. You do end up getting rid of a lot of the parts though, and if you want to go your own way on the body, potentially you could just buy:

Grasshopper 2 Chassis Tub

Grasshopper 2/Rising Fighter C Parts 0005341. You only need the battery door off this entire sprue, but it does have plastic servo and body mounts too.

Bumper 0445007

If you start with a Grasshopper 2 you need to buy the Rising Fighter D parts tree 9005919 for the rear transmission attachments, and the front tower reinforcements are nice too.

Thundershot chassis rear transmission:

A parts tree (transmission cases)

B parts tree (shock tower and rear arms mount B8)

Gear bag E 9005257

Bevel gear set 9405620

Gearbox outdrives 9805368

Countergear shaft DT9 2595043

Motor Mount 4305219

Assorted 1150 and 850 bearings (see one of the rere manuals for these)

CVA 50519 mini shock short eyelet front (64mm), CVA short shock long eyelet rear (94mm)

Lunchbox spring mount 9805082 for mounting the front CVA shocks

Assorted screwpins or suspension shafts

Thundershot D parts for the rear upper and lower arms (or you can do camber links)

Either Thundershot E parts for the rear uprights so you can use the solid D parts upper arms, or CTE RC 3 deg toe in uprights for use with camber links: http://shpws.me/SyMi

3D printed CTE RC parts:

You need the gearbox mounts: http://shpws.me/QLky

You have a choice for the front arms. Either the DT02/3 front arms, which is this part: http://shpws.me/Pqlp

In which case you need DT02/03 D parts x 2 for the front arms

If you want to have it matching blue Thundershot arms front and rear like my Ultra G then you need this part: http://shpws.me/QLkw

In this case you need an additional set of blue Thundershot D parts from the lower arms.

Regardless of which front arms you use, you need the DT02/3 B parts for c hubs and steering knuckles 100555059

The DT02 turnbuckle set 53828 has lots of useful length turnbuckles, including for the steering.

That's about it. If I think of anything else, or if you think I've missed something, let me know and I'll edit this post.

 

 

[ThunderDragonCy 7881]

Something i have been thinking about for a while: Proper steering. The current setup does work but isn't centred and is pretty basic. 

I needed to bump up a minimum order on a 3d print order so finished it up.

The base plate bolts onto the servo platform, and a boss in the middle runs on bearings to the steering link. The hoop in front of the plate is the space envelope of the opening in the chassis. 

The idea is to mount the servo low down at the back of the tub, using the old MSC servo mounting. I'll run a steering link from the servo saver using about 100mm of m3 threaded rod and ball ends. This run right to left across the chassis, on a diagonal, hence the angle on the steering link. This should get the long link running at right angles to it and the servo saver. 

Obviously it's not a full wiper steering setups (i can't figure out a way to make one fit), but it will equilise the lengths of the turnbuckles and keep them on the same level so it should help bump steer. I don't think it will be a massive improvement, but it's fun to do and won't need any chassis mods. If it works i'll get the plate in carbon to keep things stiff. 

Should be here in a couple of weeks. 

[Carmine A 2046]

Cy - that's BRILLIANT!! Is it in your Store?? 👍👍 

I've decided on the GHII... Haven't decided yet HOW crazy I want to go on the Mods - but this Steering Bellcrank... YES!!! 😁

[ThunderDragonCy 7881]

@Carmine A Thanks man. Not in my store yet as its untested. The parts just arrived today. 

[Carmine A 2046]

24 minutes ago, ThunderDragonCy said:

@Carmine A Thanks man. Not in my store yet as its untested. The parts just arrived today. 

Looking forward to finding out!! 😉

[ThunderDragonCy 7881]

Trial fit of the bearing steering. Here's the original layout

Stripped. Notice the larger servo arm aperture. 

Steering servo mounted on the MSC plate

Mounting plate. This isn't quite right. I through bolted from the front suspension mount but that angles back and i didn't account for that. Managed to get it to fit

That's a DB01 aluminum steering post, but any Tamiya steering post will do. If this works i will modify it and do a carbon one. 

This is the bellcrank. Again, got this slightly wrong on the clearance to the screws in the servo mount positions, but sorted with some spacers

Installed with some DT03 tutnbuckles

And it works! Will give a run soon

 

 

 

 

[ThunderDragonCy 7881]

Lunch run in the park. Works well and nothing broke! Had to tweak the front toe and camber a bit to get them right, and i think the ball connectors could do with a freshen up, but it run really well. I tidied up the rear with my new carbon B8, some new rear uprights as the old ones had got a bit baggy on the pivots. 

Gratuitous "Ultra G is awesome" pic

 

[Carmine A 2046]

That's AWESOME!! And it looks like a DT-02 Bellcrank - but stronger! 😊

[ThunderDragonCy 7881]

First Tamiya Junkies track meet in over 15 months. Ultra G was flippin awesome as usual. Also looking fly with its JC Racing Products orange 2.2" Astute wheels. Seriously, if you like vintage buggies, but actually want one that works, build yourself one of these. That new black edition GH2 body would look awesome, and all the thundershot chassis reres mean there's parts everywhere. 

Also ran it with the lighter Saint Dragon shell too

 

 

 

[ThunderDragonCy 7881]

After the last track run I found cracks in the cut axle mounts i used from the Rising Fighter D parts to secure the lower tabs of the transmission.

Since i first built Ultra G my 3D modelling skills have come a long way, so when i last made a 3d print order i whipped up some more solid, 1 piece chassis mounts. I fitted them today as we gave another junkies meet next weekend

The new part replaces the little 3d printed bobbins i originally did to bridge from the transmission to the stock tamiya side mounts. It's now fully enclosed, solid plastic. Seems solid and fit perfectly.

Looking forward to running it again next week.

[ThunderDragonCy 7881]

Repairs! I had broken one of the upper body mounts a while back, but the other one went at the last Junkies meet. Thought it meant a new tub until I noticed the battery posts on my new TA04. Threaded metal items. I bought some. Today I had a go at installing them. I cut the remains of the posts off. 

First I drilled 2.5mm holes. 

Threaded in. 

And fitted! Works with the Saint Dragon

And with the glorious GH2 shell. Winner! 

 

 

 

 

 

[Kol__ 3377]

2 hours ago, ThunderDragonCy said:

I had broken one of the upper body mounts a while back, but the other one went at the last Junkies meet. Thought it meant a new tub until I noticed the battery posts on my new TA04.

The G2 I bought and restored for my son, had the rear body mounts ground to almost nothing and the body shell cable tied on!

I had considered a similar repair to yours until I noticed that the front bumper mounts had also been sheared off, so a new £8 tub was definitely required!!

Anyway, a great, unique build mate and a really interesting hybrid car you've created there. Good to hear it runs so well and is being enjoyed regularly!

[KEV THE REV 2319]

Excellent work and sustained effort . It is very satisfying when a build comes together from the seed that first planted itself . Once you get the 'bones' sorted you can then carry out your own R&D along the way , as you did . Great to see it is still going strong

[ThunderDragonCy 7881]

@Kol__ @KEV THE REV Thanks fellas. I don't run off road that much these days, but whenever I do this thing is just brilliant. It's so much more fun than it has any right to be!

Oh, and the TA04 battery posts come in a set of 4, so if either of you need the other pair I have left let me know. 

[ThunderDragonCy 7881]

Ran at the Tamiya Junkies track day today and Ultra G was flipping brilliant. Fabulous fun on the astro track. Was running on the little indoor circuit when I got tangled up with another car and the shock towers snapped off the tub! They have done very well really. So it's either new tub time or see if I can figure out some kind of carbon tower. To be continued....