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jonboy1

The Mythical Jamie Booth Astute Mid....

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So, first things first, I have to give all available credit to @Thommo and his brilliant Mid Astute project,

as that was the inspiration for this. I'd seen a few Astutes with M06 gearboxes, and I think they are brilliant and might still build one of them. But, I really love the idea of making something completely alien fit somewhere it really shouldn't and creating something amazing, and @Thommo really achieved that, making a TA02 gearbox fit an Astute. Imitation is the greatest form of flattery, so I hope you feel well and truly flatter Tom! ;)

 After going and have a dig around in my spares box something became instantly apparent - I had a right mix of bits, and that was because most of what I had was left overs from when I made my OG Astute into a Jamie Booth replica https://www.tamiyaclub.com/showroom_model.asp?cid=134978&id=33463 as that ended up being taken apart and rebuilt as a standard Astute. So then the little grey cells started grinding.....

Tamiya has successfully fiddled with the position of motors on many of their chassis. One that stands out to me is the TRF201, which started out as a very capable rear motor configuration, only to evolve into a mid motor chassis as the 201XM. I got to wondering, what if Tamiya had tried the same idea back with the Astute, and specifically for me, what if Jamie Booth and his team had one?

So, thinking about what was around at the time, the Top Force had not long been around, so a TA-02 gearbox would be a viable option. Let's assume that Tamiya sent Jamie a chassis plate and a few bespoke parts for the conversion and everything else would be straight off his existing Astute. So we'd have Madcap lower arms and outer hubs, Astute steering slightly modified, Astute driveshafts, Hi Caps with square section springs - basically everything listed in the RRC article back in '91https://www.tamiyaclub.com/article.asp?id=71

Where to start then:

IMG_2416

One key thing I really wanted to retain was the iconic Astute look, so I was determined to try and keep the rear dampers in front of the arms, which proved to be a major cause of headaches.

First things first, I needed a chassis, so I bought a 3mm thick sheet of carbon fibre, grabbed my Super Astute, my TA-02 and a ruler, a cup of coffee and off I went...

....to my desk and started modelling things:

chassis.thumb.PNG.7e016217b67c82f54d5636132a5e17b0.PNG

This turned out to be the easy bit. As @Thommo quite rightly pointed out, 2 of the holes are identical, and everything ahead of that is pure Astute, so the back end just needs 2 holes and the shape from the TA-02 carbon chassis traced out. I'd debated making the front damper mount more Dynastorm -eque, but I've never loved the look of it with the taller front end, so I imparted my preference on Jamie and his team and they decided to stick with the standard height. So this was just traced out onto the 3mm carbon along with the chassis.

With the rear damper mount, as mentioned, I really wanted it to look like an Astute, so I copied the top half of the standard damper mount and cut it out of card, then after fitting the gearbox housing to the chassis, tried to work out where it needed to go and how to mount it. I'll cut a long(er) story short and tell you now it took a lot of head scratching, but eventually I came up with something that looked like it should work, so I printed everything out onto paper, cut them out and stuck them to the carbon sheet and got cutting. Top Tip: wear a mask when cutting carbon fibre  - the dust gets everywhere.....

With those 3 parts cut out it was time to start mocking things up:

IMG_2422 (1)

So far, so good.

 

The next prerequisite I enforced upon the team was that I wanted to use standard batteries. Because the gearbox comes into the mid-dle of the chassis there is no longer the length available for a longitudinal battery arrangement as on the Super Astute, because the steering servo gets in the way. This left two options: move the servo to the side, or keep the horizontal battery arrangement from the Astute. I spent many a happy hour looking at ways to relocate the servo, basically ending up with something very similar to the Avante arrangement, but then I found myself wondering, is it worth it? When you consider the motor and the majority of the gearbox is now infront of the rear wheels, the weight balance should be a lot better than the standard Astute. By moving the battery slightly further forward as well (although there isn't a whole lot you can move it) we can get a little bit more weight forward that way too. I still need to fit a servo and compare the 3 versions, but just balancing it by hand, the centre of gravity is much further forward than in the Astute,so I think it will be a good enough option.

With that decided, the next issue would be mounting the battery and body posts. I really wanted to keep the weight down, and the standard battery clamps are huge and heavy, so they had to go. They also are so wide they prevent moving the battery any further forward. So I decide to design some nice light ones that can lift and swivel out of the way. As the Astute bulkhead had gone, there were no rear body posts, so I came up with a way of combining the battery mount with the body post, the only negative being that they had to come forward about 20mm, so I now have 2 spare holes in the body.

Reasonably happy with the design, I sent the parts off to the printers, ordered the last few bits and bobs and waited.....

I've not got any mid build pictures sorry, as I did it in little 5 min spare windows here and there, but the long and the short of it is the design changed a bit from where I expected it to be. My original plan had been for the upper turnbuckles for the rear to be mounted infront of the axle and pick up off the back of the damper mount. The problem I found was that the angle they sat at was too big, so the wheels tilted down and in as the dampers were compressed. I couldn't move the mount because the gearbox got in the way. I fixed it by putting the turnbuckle mount behind the gearbox where the rear damper mount would be on the TA-02/Top Force and fitting it with a little carbon fibre bracket. This was actually a very positive move, as it looks so much better balanced now and it also allowed the lower arms to move forward a couple of mm too.

Finally, with a very minimal amount of trimming to the body, it was complete:

IMG_2474 IMG_2477

light weight flexi battery clamps in action

IMG_2476

period correct dynatech motor (colour coordinated too) although I do still have the Team LRP motor from the replica I could use. There's a ball diff in the gearbox and all fittings and hardware are period correct (possibly excluding the turnbuckles, but I think threaded rod is just ugly)

IMG_2479

I 3Dprinted a replica Super Astute front brace as I couldn't find one anywhere.

Oh, and I gave it a name:

IMG_2478

AstuDF. Taken from Astute and DF - the Top Force chassis.

IMG_2472

Body just needed a slight trim to clear the mount. I decided on Super Astute wheels over the standard Astute rear and Wild One rear purely for aesthetics.

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Rear turnbuckle mount needs a trim to remove extra holes I didn't need.

Ta-da!

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I'll get a servo in and some radio gear and battery and give it all a weigh and find out how it compares with the other 2, and then you never know, I might just give it a run. Maybe. 

Indoors of course.

On a nice soft carpet.

 

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This is FANTASTIC! Round of applause. Love these Astute Mid conversions. Excellent all round. 

What material did you print the flexy battery mounts in? They are brilliant. 

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Very nice posting, just right for coffee and biscuits breakfast. :wub:

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thank you very much for the great comments guys - very much appreciate them :wub::wub::wub:

@ThunderDragonCy - material was PA12 MJF - I find that if you keep the bend radii nice and generous you can get quite aggressive with how much you can get it to bend. These clamps are 2mm thick and I'm sure they could take  more abuse than I've given them so far.

I got the other 2 Astutes out for a comparison group shot and noticed something odd:

IMG_2482

Somehow I've got the wheelbase about 7mm longer than stock. Looking at the gap between the rear damper and the body it becomes clear where it has come from:

IMG_2481

I can only assume it's down to my dodgy measurements, as it wouldn't have any effect on how the gearbox fits or the dampers mount to that. Now I can see it I can't stop seeing it, and it's really annoying me now, so I might have to make a new chassis.

Anyway, that aside, here's a nice group shot:

IMG_2486 IMG_2487

 

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Thank you for the kind words.  There is a lot that I really like about this and I'll contribute more when I have more time.

Madcap front arms do result in a longer wheelbase also !   I always space the front upper damper mounts out by 3mm when using Madcap front arms too..... always have.

 

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52 minutes ago, jonboy1 said:

 

@ThunderDragonCy - material was PA12 MJF - I find that if you keep the bend radii nice and generous you can get quite aggressive with how much you can get it to bend. These clamps are 2mm thick and I'm sure they could take  more abuse than I've given them so far.

Oh that's very interesting (for a different application). Thank you. 

But more importantly - lovely car. Stunning work. Am in awe. 

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I love things like this, absolutely Mad Skills, wish I had the ability to design stuff like this, and then execute. Great job

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I thought I heard "Jamie Booth"'s name mentioned as one of the drivers in the old Tamiya mudbusters video?

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No slippery clutch, the gear train will break, sorry.
Anyway great project.

Max

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A quick little update on this. After lots and lots of head scratching and measuring I worked out what was going on with the slightly odd look of the rear dampers and the wheelbase. The latter was exactly what @Thommo said it was, the Madcap front arms give a longer wheelbase - confirmed by @kontemax's great post of the differences between the variations over on the forum that cannot be discussed here. ;) The visual disparity turned out to be the shape of the Madcap rear arms  - the leading face that the lower damper mount is on is much further back than on the Astute versions (the arm is thinner in simple terms) so it sits much further back from the body. The other issue is that I think I put the rear damper mount a little too far back. So, I've redesigned the mount, which will also mean the dampers sit more upright, as they are leaning back a bit at the moment. Hopefully it will also mean I can bring the rear wheel axles forward ever so slightly, which will get them running perfectly in line with the gearbox (not necessary as anyone who has ever looked at the TA-02 rear axles and thought "that can't be right" but I'm a bit of a perfectionist if you hadn't noticed.)

I've also designed a new rear turnbuckle mount that drops the angle slightly so the turnbuckles should sit parallel to the lower arms and I've also printed a new front bumper for it (only had an old used one, and that just would never do!) I got an email from the printers yesterday to say they had sent it to print, so I hope to have these by the end of the week.

Oh, and I also fitted the steering servo and linkage. Once I get the new printed parts fitted I'll borrow an ESC from another car and then I can compare the weights and centre of gravities.

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15 hours ago, kontemax said:

No slippery clutch, the gear train will break, sorry.
Anyway great project.

Max

Thanks Max.

So I've been doing some reading on this subject and there are several topics that seem to contradict what you have said about the gear train breaking, and on a couple of them you agree with the solutions:

In my build (and I think @Thommo's too) there is a ball diff fitted, lightweight pressure plates and a mild motor (Dynatech 01R) - which matches what you say is ok above. Have you discovered something else since then? 

I can fully appreciate how a gear diff with a high power motor on a grippy surface could get explosive, but a ball diff with a brushed motor on a gravel/grass surface should be fine, surely? 

 

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4 hours ago, jonboy1 said:

Thanks Max.

So I've been doing some reading on this subject and there are several topics that seem to contradict what you have said about the gear train breaking, and on a couple of them you agree with the solutions:

Hi, I'm sorry to be the bad news man but I have many experience on TA01/TA02 geartrain converted to 2WD.
Ball differential can help but you will grind it. It will become "rough" cause the diff balls will slip against the diff pressure plates.
The big problem is when you get some jump, the landing is a problem.
Then every bump on the track is a problem.
Every time the wheel will loose traction and then will get full traction again is a problem. Everytime it happens is a rip on the geartrain.
Without a slippery clutch the gears will worn out very quickly or they will break. Or you will rip the top gear cover and will destroy the iddle gear or the spur gear.
No intensive use is needed, just a normal use is enough.
On single rip could be enough to break something.
This is the reason why the 4WD TA-01 chassis has the rear ball diff and not the front ball diff.
This is my experience.

Max

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As promised, here's the latest update on the AstuDF. 

The new rear strut mount, turnbuckle mount and front bumper all arrived and fitted perfectly. I also fitted some new spacers between the mount and the chassis plate, as these were made up of 2 different length ones previously. 

IMG_2545 IMG_2549 IMG_2546

So we've fixed the angle of dangle and the space between the rear wheels and the chassis being too big. I haven't actually put this next to the other Astutes to see how they compare in wheelbase yet, but visually if nothing else, it looks a lot better, to me at least! :) 

The camber arms to the rear wheels look much better now they are just about parallel to the lower arms, so I'm happy with that too.

Job done, right?

 

no....

 

I couldn't leave it with the thought that @kontemax would be having sleepless nights about my gearbox destroying itself, so I resolved myself to fixing this :) 

Off to the googleweb I went, searching and searching for an answer. As luck would have it, the answer appeared to be on the TamiyaClub forum all the time:

 

The mythical pinion slipper for the mythical Jamie Booth Astute-Mid!

It's fair to say it's not a direct fit. Firstly, it seems to take an imagination the size of Scun-thorpe to work out how the thing goes together, as there don't appear to be any instructions anywhere for it. If someone has some, I'd love to see them, because I'm still not 100% convinced I've done it right! Secondly, it takes some fettling to get in in place.

IMG_2547

You can just about see the end of it poking it's nut out of the end of the gear case. Don't worry everyone, it won't be run like that!! :)  I'm in the process of making a dust cap for it. Not only does it poke out too far in that direction, it does the same in the other direction too, so I had to get creative with how I mounted the motor too:

IMG_2548

So I've fitted some spacers between the motor and the mounting ring. Again, I don't foresee this being a permanent fix, I'm not sure how the torque of the motor would appreciate it not being mounted flat across the whole face, so I'll make a proper full diameter spacer for this. But, all that faff aside, it seems to fit together ok.

Unfortunately, pushing the motor out meant that it now just catches the spring on the damper, so I had to move the rear arms back again a millimeter. 

IMG_2552

and it also means the end of the motor just pokes out of the back of the body. If it had something like a Sport Tuned in there it would still fit nicely in the body, or even if the orientation of the motor was slightly different, so when I make the mount I might see if I can turn it 90 degrees.

Last thing to do was trim the other side of the body and hey presto, it's done!

IMG_2553 IMG_2555

I think I'll do a new body for it at some point, or at least change the stickers around a bit, as the sponsors aren't relevant anymore, but I can't see that happening any time soon as I've got several other projects in the works.....

Next stop - time too see how it goes! I've almost convinced myself to give this a run around the park along with the CWM06 mashup, as I'm really interested to see how that handles, so hopefully I'll muster up enough courage to do it.

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