Super Astute LWB chassis

[Kol__ 3513]

Starting off a thread for discussion on a long wheel base chassis option for the Super Astute / Astute.

@Kapt_Cavern, great shots you added to that other thread, I'll add then below for context.

I did a very crude side by side comparison with the original chassis on the left below. It looks like all the extension is at the rear where the chassis thins out for the mounting of the drive train. Is that correct @Kapt_Cavern?

What are your thoughts about recreating it @BuggyDad?

[BuggyDad 5894]

Interesting. Extending it only in the thin section at the rear I had not thought of, but it has a lot going for it doesn't it? It maintains perfect body fitment for starters, and brings the centre of gravity a little forward. And it would also be the easiest way for me to add wheelbase to an existing CAD drawing. My initial reaction is it's a stroke of genius. Far superior to stretching the mid chassis. 

What does it do to the other parts in the rear Bulkhead to gearbox area? Am I right that the only other modification required would be to alter the little rear upper deck to bring its swept out sides forward before they come out? I'm not yet familiar with the build, but I do have a NIB Super Astute to get to shortly. And, I have on my to do list to model this part and the towers anyway. I owe a full set of carbon parts to a friend. And this is another easy drawing change. 

Undertray is going to come up short at the back but it'll fit otherwise, which it also wouldn't with an extended mid chassis. 

With the extended area being narrow, but double deck, it is likely, perhaps counterintuitively, also the stiffest/strongest LWB design too. 

Now, how much extra wheelbase would sir desire? 10mm, 20mm, 150mm? Perhaps I could interest you in a 6 wheeler? 

[ThunderDragonCy 8361]

Rear end extension like that was popular on rear motor buggies before mid motor became the thing. There was a +7mm thing for the TRF201 that effectively pushed the trans rearward. I love stuff like this. Longer chassis with BBX trans but otherwise Astute would laaaaaaaavely

[BuggyDad 5894]

14 minutes ago, ThunderDragonCy said:

Longer chassis with BBX trans but otherwise Astute would laaaaaaaavely

My loose plan is to get the stock SA parts all modelled up first, and also build mine, then I should be well placed to see how best the BBX gearbox slots in, which is what I intend for my runner. I don't think I'll use SA suspension mounting for that, more likely I'll nick what I did on Mohawk, which uses the TD4 adjustable rear mount and longer pins. 

On either chassis a wheelbase extension like this would be a piece of cake I think. 

The work is in getting the measurements just right. I find it harder to copy something than design my own part! 

[BuggyDad 5894]

On a related note, I may also model a taller front shock tower. I'm kind of guessing that @Kapt_Cavern's up there is a pretty ideal modern shock middle ground between orig Astute and the Dynastorm's very leggy front shocks, so I had something similar in mind.

[Kol__ 3513]

5 hours ago, BuggyDad said:

What does it do to the other parts in the rear Bulkhead to gearbox area? Am I right that the only other modification required would be to alter the little rear upper deck to bring its swept out sides forward before they come out

So the gearbox is linked to the rear bulk head by that small FRP piece, Tamiya call it 'chassis sub-section'. See snaps of the manual below for how they are fitted together.

From the looks of it that chassis sub-section plate on @Kapt_Cavern LWB chassis kit is longer. As I see it, this is because the body shell rear mounts would need to stay in the same place, whilst the shock tower moves back with the rest of the gearbox assembly, keeping the top of the shocks in line with the rear arms they mount to at the bottom. I guess it would simply be a case of whatever mm's you add to the length of the main chassis, you'd need to add the same amount to the chassis sub-section plate.

So what you thinking then, 20mm longer? @Kapt_Cavern, what is the overall length of your LWB chassis?

3 hours ago, BuggyDad said:

On a related note, I may also model a taller front shock tower. I'm kind of guessing that @Kapt_Cavern's up there is a pretty ideal modern shock middle ground between orig Astute and the Dynastorm's very leggy front shocks, so I had something similar in mind.

Yeah, I've picked up a 6mm taller front shock tower to allow for the fitment of the big bore shocks.

[BuggyDad 5894]

27 minutes ago, Kol__ said:

From the looks of it that chassis sub-section plate on @Kapt_Cavern LWB chassis kit is longer. As I see it, this is because the body shell rear mounts would need to stay in the same place, whilst the shock tower moves back with the rest of the gearbox assembly, keeping the top of the shocks in line with the rear arms they mount to at the bottom. I guess it would simply be a case of whatever mm's you add to the length of the main chassis, you'd need to add the same amount to the chassis sub-section plate.

So what you thinking then, 20mm longer?

Yeah, I have in my head exactly how I'd amend the "chassis sub section". Should be a piece of cake. 

SA stock wheelbase is 267mm. 285mm is right at the long/modern end for buggies I think? In CAD work terms it makes no difference at all and I could model any length. In stock material terms I might need to buy some new sheet if we got over a certain length, but that's no biggie - I'll probably need more anyway. 

[Kol__ 3513]

14 minutes ago, BuggyDad said:

Yeah, I have in my head exactly how I'd amend the "chassis sub section". Should be a piece of cake. 

SA stock wheelbase is 267mm. 285mm is right at the long/modern end for buggies I think? In CAD work terms it makes no difference at all and I could model any length. In stock material terms I might need to buy some new sheet if we got over a certain length, but that's no biggie - I'll probably need more anyway. 

Right then, count me in for 285mm chassis mate👍

[ThunderDragonCy 8361]

Given my dt03 is 289 and a bit hard to get weight forward that might be going some. Although I believe the 289 on that came from the trf201XR conversion. Regular TRF201 was 272, and the aftermarket extension part was +7mm from memory, so 279. I probably wouldn't go longer than that if it were me. Or maybe a nice round 280

[BuggyDad 5894]

4 hours ago, ThunderDragonCy said:

Given my dt03 is 289 and a bit hard to get weight forward that might be going some. Although I believe the 289 on that came from the trf201XR conversion. Regular TRF201 was 272, and the aftermarket extension part was +7mm from memory, so 279. I probably wouldn't go longer than that if it were me. Or maybe a nice round 280

Yeah this is kind of where I was - somewhere between stock Astute and modern stuff. +20mm is an extreme, while say +10-12mm is still an Astute but with a twist. But, end of the day, once I've got the process sorted it won't be that hard to run off another, so we can try some options. A first LWB cut could also be a way to refine my process without complete waste, so a bit scrappy round the edges or maybe a servo or battery placement 1mm off, @Kol__ maybe you'd fancy trying the first rough tester as a LWB driving experiment since you've got a runner you already know well? I wouldn't be much use myself since I'm yet to drive a stock SA. 

[Lovebug 2]

14 hours ago, Kol__ said:

So the gearbox is linked to the rear bulk head by that small FRP piece, Tamiya call it 'chassis sub-section'. See snaps of the manual below for how they are fitted together.

From the looks of it that chassis sub-section plate on @Kapt_Cavern LWB chassis kit is longer. As I see it, this is because the body shell rear mounts would need to stay in the same place, whilst the shock tower moves back with the rest of the gearbox assembly, keeping the top of the shocks in line with the rear arms they mount to at the bottom. I guess it would simply be a case of whatever mm's you add to the length of the main chassis, you'd need to add the same amount to the chassis sub-section plate.

So what you thinking then, 20mm longer? @Kapt_Cavern, what is the overall length of your LWB chassis?

Yeah, I've picked up a 6mm taller front shock tower to allow for the fitment of the big bore shocks.

I used to own a original Super Astute and when you use the velcro you can bypass using the body pins if you want to...

I think a extended long wheel base would be great and make it different and MIGHT cause understeering...

Moving the Battery rearwards would help a little... 

[BuggyDad 5894]

1 hour ago, Lovebug said:

I think a extended long wheel base would be great and make it different and MIGHT cause understeering...

Moving the Battery rearwards would help a little...

Wouldn't you use a forwards weight shift to reduce understeer? 

But yeah, understeer is the risk of extending the chassis, which is why I thought I'd experiment with a relatively small increase to wheelbase initially. 

[Kapt_Cavern 16]

Hi, I'll give you more informations this week-end.

Cheers

[Kol__ 3513]

On 11/27/2024 at 11:13 PM, BuggyDad said:

Yeah this is kind of where I was - somewhere between stock Astute and modern stuff. +20mm is an extreme, while say +10-12mm is still an Astute but with a twist. But, end of the day, once I've got the process sorted it won't be that hard to run off another, so we can try some options. A first LWB cut could also be a way to refine my process without complete waste, so a bit scrappy round the edges or maybe a servo or battery placement 1mm off, @Kol__ maybe you'd fancy trying the first rough tester as a LWB driving experiment since you've got a runner you already know well? I wouldn't be much use myself since I'm yet to drive a stock SA. 

Yeah no problem mate. So maybe we should start with 10mm increase then? Just drop me a PM when you've got it ready. In the meantime, I'm currently waiting for the Xtra Speed alloy front bulk head to come back from the anodiser. So I'll need to rebuild the buggy and run it as is, as that bulk head adds weight to the front end. And then I can start test driving the LWB chassis.

[BuggyDad 5894]

39 minutes ago, Kol__ said:

Yeah no problem mate. So maybe we should start with 10mm increase then? Just drop me a PM when you've got it ready. In the meantime, I'm currently waiting for the Xtra Speed alloy front bulk head to come back from the anodiser. So I'll need to rebuild the buggy and run it as is, as that bulk head adds weight to the front end. And then I can start test driving the LWB chassis.

I've got one of those bulkheads on the way too. Anodising is a nice idea. Is it expensive? 

Yeah I reckon 10mm is a wise start point I think. Will PM you. 

[Kol__ 3513]

I'm building a Kyosho Javelin and doing some, largely cosmetic, changes. I've given the anodiser a little over 30 parts to strip and redcoat in black, he reckons £30-40 for the lot. So at around a £1 per part, I reckon that's good value😁

Within those parts being anodised are some parts for my Madcap/Astute runner. So the afore mentioned bulk head is going black. And also a set of Tamiya big bores that I'm changing the bronze shock bodies to an anthracite grey to match my Madcap shell and the blue bits are going black.

Ok mate, thanks will keep an eye out for the PM👍

[BuggyDad 5894]

2 minutes ago, Kol__ said:

I've given the anodiser a little over 30 parts to strip and redcoat in black, he reckons £30-40 for the lot. So at around a £1 per part, I reckon that's good value😁

Blimey. That's amazing value. Will things like shock body threads be OK? Doesn't really add anything to the dimensions I guess, anodising? 

[Kol__ 3513]

Yeah, I was pleasantly surprised with the quote. Tbh though the parts are all new and previously coated, so I don't believe it's much of a process to dump them all into a bath to chemically strip them and recoat them all black (except for the shock bodies going grey). And yeah that's the beauty of anodising, it changes the colour of the aluminium surface, but adds no thickness. The shock bodies and their threads etc. were already coated by Tamiya, so it's just being removed and recoloured.

Here's most of the parts...

And yes that is what is left of the current (original) wing😂 I have a new shell and wing to spray up in the same colour and sticker design as the current one, using @Muso31s far superior, thicker polycarbonate Madcap body shell and wing.

[BuggyDad 5894]

2 minutes ago, Kol__ said:

using @Muso31s far superior, thicker polycarbonate Madcap body shell and wing

Ooh. I've got a Madcap body and wing in my basket with Penguin. Should I rethink? 

[Kol__ 3513]

1 minute ago, BuggyDad said:

Ooh. I've got a Madcap body and wing in my basket with Penguin. Should I rethink? 

If @Muso31 is still producing them, then yes I'd certainly hold off on the Penguin set and drop him a PM bud👍 Penguin is decent, but the one Muso produced is something else😎

[BuggyDad 5894]

2 hours ago, Kol__ said:

Just drop me a PM

Hey @Kol__ I tried to PM you but it says "cannot receive messages" - maybe your inbox is full? 

[Kol__ 3513]

8 hours ago, BuggyDad said:

Hey @Kol__ I tried to PM you but it says "cannot receive messages" - maybe your inbox is full? 

Ah yes, you're right mate. I just checked and it said I was 101% full😂 I've made some space now 👍

[BuggyDad 5894]

11 hours ago, Kol__ said:

If @Muso31 is still producing them, then yes I'd certainly hold off on the Penguin set and drop him a PM bud👍 Penguin is decent, but the one Muso produced is something else😎

Cool. Ta. Turns out he's not, sadly, but TBG have a Black Friday offer on at the mo so I think I'm going to try one of theirs. They are generally considered to be about the highest quality / most detailed of the after market producers. 

[BuggyDad 5894]

Had a moment to extend the wheelbase 10mm on my CAD models. Work of moments as expected. 

 

To my eye, 10mm looks like quite a lot here. 

[Kol__ 3513]

Looks very similar to @Kapt_Caverns vintage chassis. Kapt, we await your measurements when you have a mo buddy.