Frog Evo and Sand Scorcher Evo builds

[jonboy1 3754]

or "And so dear friend, we shall begin our journey into another bout of stockpiled pieces of 3D printed plastic that have no use"  

Tamiya threw a big (but beautifully made of course) spanner into the Jonboy1 Works with the Hornet Evo, as that was my next plan for a reimagining following my FAV project. It's definitely not the way I would have done it, but I'm glad they have given it a go, and I'll still tackle it (I'm determined to find a way to improve the front damper arrangement without cutting the chassis!!) but for now I am focussing on the Frog. 

The ORV chassis was actually the first Tamiya I owned, in the form of a Blackfoot. It was always a love/hate relationship with me, as I really wanted a Monster Beetle, but the LHS didn't have one, and then they released the Lunchbox and that just made me go off the Blackfoot even more. Despite this, I loved running it and I have to say, never had an issue with it breaking or clicky diffs or anything (it was totally stock running on a ni-cad, so it was never stressed) - it was just a little less "cool" than some of it's brethren (to a 11 year old me at least.) My path didn't cross with an ORV until 2016 when I bought a Frog from Greece. It turned out to be an XB built model which was missing a front hub but otherwise complete. Long story short, I sold the body set and converted the chassis into a Brat which I built for a friend. At some point in the interim I think I must have had a plan to build it into something (the little grey cells are leaning me towards a Ford Ranger body for some reason) as I found this picture of the chassis fully repainted and rebuilt:

Anyway, that never happened, and a Frog never crossed my mind again until Tamiya released the Hornet Evo. It was then that I started pondering other models to rework and the Frog came to the forefront. 

So - what was I going to do with it?

As with my other reimagined models, it had to be 100% reversible with no cutting or drilling to the chassis. I wanted it to have proper buggy style wishbone suspension, better steering and a better transmission, but most importantly, be instantly recognisable as a Frog, but nicer.  

It might sound odd place to start, but I began with the steering. The reasons being that It would determine where the servo went and with the steering arms and hubs all in place I would have a few key bits in place to work around (and with) for the suspension. It had nothing at all to do with me designing myself literally into a corner with the FAV steering, oh no!  The basic set up I designed for the FAV seemed like a good place to start, so, I did. I also reused the hubs and uprights (albeit slightly tweaked for this application):

The steering mount itself fits around the lugs at the front of the chassis and turns into a platform for the pivot points. Oh, forgot to mention, the wheelbase and width across the hubs were all to stay the same as original. 

Next up, the front suspension. I was ok with changing the appearance of the Frog in this instance, as there was no way I was keeping the spring plungers, so some form of upright was needed for the dampers. Team CRP along with others have previously designed damper mounts that attached to the original suspension, but they didn't resolve the lack of fully adjustable suspension or the lack of kick up, so I needed to give this some more thought.

In my mind, this looks a bit like a frog. Yes, I am on medication......

 

 

 

Edited August 20, 2024 by jonboy1
SRB corrected to ORV - sorry!!

[jonboy1 3754]

And so to the rear.

Once again I found myself favouring the m-06 transmission, but as a nod to the original I decided to orientate it vertically, so the motor is at the top. With it positioned with the axles in the right place for the wheelbase and ride height, it was just a case of making mounts to attach it to the chassis:

This is where it got a bit more interesting. 

On the original, the rear dampers lay horizontal and attach to the rear cantilever arms, like this:

As mentioned earlier, I wanted to keep this looking as Frog-like as possible, so didn't want to have an upright suspension arrangement in the rear, especially as I'd already gone that way in the front. The issue though, is that now I have wishbone suspension in the back I don't have the means to push the damper towards the front of the buggy. The answer: pushrod suspension! So taking some inspiration from the front of the TD2.....:

Obviously there are the linkages missing, but hopefully you get the general idea. Whether it will work or not - who knows. I'm guessing no...

So with a few little bits and bobs scattered in here and there we got to this:

and this is where I've decided to put a pin in it and just order the parts and see where we're at. I've tried to be a bit more methodical with the design of this one, following from lessons learned with the FAV. The driveshafts for example. On the FAV I had incorporated spacers into the arms so I could adjust the track width to accommodate standard driveshafts. In practice, I hadn't been as clever as I thought (no, really?) as I'd managed to end up right off the wrong side of a standard size, so had to add more spacer than I really wanted to to make the next standard one fit. As I didn't want to use ball adjusters and spacers on the wishbones of this I needed to design them with a specific driveshaft arrangement in mind, so the rear track has actually ended up very slightly narrower than stock, but with a couple of wider hub drives I can get back to stock width.

Last thing that had to change was the front bumper. Why the original one had to look like it was in a different postcode to the rest of the buggy I will never know, but as I'd ditched the front radius arms I no longer needed the front mounts that are part of the bumper mount, so something much slimmer and more "attached" to the buggy could be had.

So, parts are in production, I've already ordered all the ancillary parts and the body etc, so once printed I can start building! Well, attempt building until I realise I've made a mistake and need to get new parts printed. And then repeat several more times.....

Updates to come......

[El Gecko 1637]

7 hours ago, jonboy1 said:

The SRB chassis was actually the first Tamiya I owned, in the form of a Blackfoot.

Sorry for the nitpick, but I believe you mean... the ORV chassis?

[jonboy1 3754]

39 minutes ago, El Gecko said:

Sorry for the nitpick, but I believe you mean... the ORV chassis?

You are completely correct, and I am very wrong. My mistake, I'll correct it now. Thank you!  

[Re-Bugged 11948]

Nice 👍🏻 All looks very technical, good luck mate. 

[Grumpy pants 5549]

16 hours ago, jonboy1 said:

You are completely correct, and I am very wrong. My mistake, I'll correct it now. Thank you!  

You were just checking, that we were paying attention 😉

[jonboy1 3754]

Well, that didn't take long.....

The printed parts are due to arrive this afternoon, and I've already decided I'm not going to use at least a quarter of them 

I was looking at it and found myself thinking "why have you gone for a conventional front end?" and couldn't come up with a good reason other than being lazy.

So........

it's still very much a work in progress but I think I can just about get it to fit. Currently I'm thinking I'll make a carbon skid plate to mount to the bottom of the chassis and fit a low profile servo to that and have some block/pillars to mount the steering assembly to that with. I still need somewhere to fix the camber arms to, so I think I'll reuse the damper upright mount but add a platform for the pushrod links for the dampers and then I can mount the dampers in the frame above the servo.

I think....

I should get a better idea of how it'll all work when I start making up the rear end. In the meantime I need for caffeine for brain juice!

[ThunderDragonCy 8974]

8 hours ago, jonboy1 said:

Well, that didn't take long.....

The printed parts are due to arrive this afternoon, and I've already decided I'm not going to use at least a quarter of them 

I was looking at it and found myself thinking "why have you gone for a conventional front end?" and couldn't come up with a good reason other than being lazy.

So........

it's still very much a work in progress but I think I can just about get it to fit. Currently I'm thinking I'll make a carbon skid plate to mount to the bottom of the chassis and fit a low profile servo to that and have some block/pillars to mount the steering assembly to that with. I still need somewhere to fix the camber arms to, so I think I'll reuse the damper upright mount but add a platform for the pushrod links for the dampers and then I can mount the dampers in the frame above the servo.

I think....

I should get a better idea of how it'll all work when I start making up the rear end. In the meantime I need for caffeine for brain juice!

This is excellent. Can also totally relate to immediately trashing 3d print parts before they arrive 😆

[jonboy1 3754]

So, an eventful month or so has seen this project stall a little. First, my younger sister in law (who I see as more of a foster daughter as she and her younger brother lived with us on and off for about 9 years from when she was 11) in the space of a week had a gorgeous little baby girl and then was diagnosed with a brain tumour. 2 days before she had her operation, my dad suddenly passed away.  

Moving forward to now, the surgery went well, although they found the tumour was bigger than they first thought, so her recovery has been slower than hoped, but 2 days ago she was told she could go home and the post op scan showed they had removed all the tumour and it wasn't malignant   The funeral for my dad went well and he had over 200 people turn up to show their respect at his memorial, so he had a good send off  

Although my concentration has been completely shot for the past few weeks, I have found it therapeutic to come back to this from time to time to escape to something not horrible, so I've managed to come up with what I hope is a viable design for this thing!

First observation that has really struck me is - why is the chassis so narrow!!!??? I thought it would be so easy to stick a servo on it's side for the steering, but no! It has been a huge faff to even get a low profile one in there!!

Second, despite it looking like there is a good amount of space vertically in the middle of the chassis, it is in-fact a reverse tardis - there is no space there at all!!! Despite these little trials, I decided that having brackets and mounts fixed to the outside of the chassis for the front cantilever suspension just wasn't good enough, so I have squeezed and squashed and pushed to make everything fit inside. Obviously, if I had conceded to add extra holes to the chassis it would have made things somewhat easier, but I'm nothing if not stubborn and pig-headed. 🐷

I put together the rear end, or rather I tried to, and discovered my ruler has been fibbing to me! There was just no way the transmission mounts were going to line up with the back end of the chassis, and after a lot of checking and double checking and template making I realised I'd got 1 dimension off by 5mm which had pushed everything else out of whack. So, I've had to reprint both mounts plus the little side brackets for the damper mounts. I also discovered I had made a rookie mistake and had made the pushrod arms for the dampers equal in length to the travel of the damper, rather than using the circumference, so they were far too big, which again meant that everything needed to move again. And so I return back to the opening line of this build thread: "And so dear friend, we shall begin our journey into another bout of stockpiled pieces of 3D printed plastic that have no use" 

So after lots more checks, I decided that I may as well stick another pin in this pin cushion of a design and send the files off to the printer. The current version now looks something like this:

The parts should turn up early next week, so I'll order some more cutting wheels for my dremel in anticipation!  

Oh, and I realised I had fitted an M03 gear diff which had the flats on the drive and had outdrives with the splines, so had to take the whole thing apart to replace the gears! 🤦‍♂️🙄😭

Ah well.......

 

[mtbkym01 4778]

Sorry to hear about those issues. Talk about when it rains it pours. Good news at least around your sister in law.

[JimBear 1302]

Bad stuff ... and some good stuff, too. Sorry to hear about your dad, but great that your sisters' tumour was non-malignant.

As for the ORV Frog thing ... well, I am struggling with an original ORV chassis. It does have its (Tamiya) quirks indeed! Hope yours turn out better!

And yes, I agree on the therapeutic nature of building ... it does help.

[Grumpy pants 5549]

@jonboy1, I’m really sorry to read your news about your dad and sister in law.

Tough times no doubt, hopefully you’re ok and your sister in law is well and truly on the road to recovery. 

[Re-Bugged 11948]

Condolences for your Dad, he must have been a popular guy by the sounds of the attendants.

Thoughts are with the new mother for a full recovery too.

Looking forward to Phase 2 printed parts, just a quick question though, have you tried the Frog body on there at all? The motor position looks a far bit higher, I’m wondering if the body will need cutting? 

[jonboy1 3754]

thanks everyone - very much appreciate all your kind words.

@mtbkym01 - It has certainly been heavy on the precipitation this month, that's for sure! Hopefully clearer skies ahead though  My dad had dementia and Parkinsons, so it's been a horrible few years watching him gradually disappear, and the last week was just horrible, it's a truly degrading way to end an accomplished and respected life, but at least he is at peace now.

Sis in law was very worrying, as they said she should be home a couple of days after the surgery, but when she came round she was paralysed down her entire right side and couldn't speak at all, none of which they said might happen. The surgeon did apologise eventually, saying her pre-cognitive test results were so good they assumed the brain had already re-mapped itself around the tumour, so there wouldn't be any degradation in her faculties. Evidently this hadn't happened. So they moved her to a specialist neuro rehab hospital for 3 weeks, and she is now walking unaided and has most of the movement in her arm back. Talking comes and goes depending on how tired she is - occasionally turning up in Spanish (she learned it a few years ago) but is all heading in the right direction. I think being back with her baby will be tremendously helpful for her recovery now, so hopefully good things ahead....  

@Re-Bugged - good point! I think it looks worse than it is, odd perspective. From what I can tell on a standard Frog, the centre of the motor is about level with the upper rear chassis mount for the transmission. My motor is within a gnats whisker of that, so from that aspect, should be ok. However...... There is the frame of the M06 transmission over the top of this, which obviously isn't there on the ORV, so depending on whether or not this sits within the body or not I may have a slight issue. Worst case, I might have to lower the whole transmission a few more millimeters, which should only result in a slightly higher rear ride height, or more sag needed in the suspension - i think! Oh, and more redundant printed parts of course!!! 

The easier way of fixing it would be to raise the back of the body up a bit, but if anything I'd prefer to lower it (although I don't think it's possible, been so long since I had one of these I really don't remember) so I won't be doing that.

[ThunderDragonCy 8974]

@jonboy1 Really hope those brighter skies are on their way. badword's teeth that's a tough few weeks. Glad you had RC projects as your 'not horrible' thing to look at. I hope it's warm and cosy in the CAD cave.....

[jonboy1 3754]

So, I'm not saying this is @Re-Bugged fault, but I am blaming him completely 

 

On 9/13/2024 at 12:02 AM, Re-Bugged said:

Looking forward to Phase 2 printed parts, just a quick question though, have you tried the Frog body on there at all? The motor position looks a far bit higher, I’m wondering if the body will need cutting? 

 

He had to go and say it didn't he??!!

So I did. And it didn't fit......

 

However, it wasn't the issue @Re-Bugged raised, but it was related. The motor was ok in terms of height, the issue was how far back it sat:

If you compare that to a side view of a standard Frog:

You can see the motor will be way out past the back of the body  

And so another round of redesigning was embarked upon....

What I've ended up doing is rotating the transmission around the drive outputs, so the wheelbase stays the same, but brought the motor closer to the chassis:

I can't bring it much closer than this, so if it doesn't fit now I'll either have to lower the transmission, which will mean it'll have more of a nose-down stance, or rotate the transmission even further so it is fully upside-down with the motor tucked up next to the battery.

What I will be doing this time is making a cardboard cut-out to save on me ordering more parts destined straight for the scrap pile.....

This is all your fault @Re-Bugged!!!!!! 

 

 

[Re-Bugged 11948]

Sorry mate…….nah not really 😉

Thats a cool funky new motor layout now though 👍🏻 

And if the worst comes to the worst and the Frog body still doesn’t fit the I’m sure a Sand Scorcher will 🥳 & one can never have enough Sand Scorchers can they 😃

Keep up the great work 👏🏻👏🏻

[Grumpy pants 5549]

Very clever @jonboy1.

I’m now even starting to like the look of the Frog 😎

[StueyS 49]

Hi, this is my Frog as raced at the September Iconic Revival in the UK.

[Carmine A 3134]

Jon.... between you and @ThunderDragonCy .... you're making Tamiya less quirky (horrible) and more quirky (good)!! I've admired your work for years. 

This is something I'm going to want to do... on the Subie Brat that I've always wanted but never owned. With that, since the Brat has specific wheel arches... is the wheelbase altered in any way? Could it even be adjusted to more perfectly fit the Brat's arches? 

Of course I realize changing wheelbase ISN'T easy on such a thing. I'm just curious. The thought of an ORV that doesn't act like it doesn't have any suspension, makes me want one!

[jonboy1 3754]

Hey @Carmine A - good to see you back on the forum! I remember you saying you had big hopes for your windfall, so I'm sorry to read it didn't pan out quite as hoped, and your move/storage issues sound like they certainly didn't improve things!  Glad to hear you are keeping upbeat and positive about it. I think one thing we can all agree on here is that RC is very therapeutic and does us all a lot of good.

Thank you very much for the kind words, although I would never put my stuff in the same class as the @ThunderDragonCy's kit: his is well thought out and considered and incrementally improved and has a purpose - mine is just random tinkering to make things purdee  

To answer your questions: I've kept the wheelbase and track width front and back exactly the same as the standard Frog. It should be possible to change the wheelbase, longer would be much easier than shorter, but there should be movement possible in both directions. That is of course always assuming this thing will work at all, so let's not get ahead of ourselves here! 

I got an email yesterday to say my new parts will be delivered today, so hopefully I will be able to get this built finally! I've gone through about 4 more iterations since my last update (thankfully only in CAD rather than printed parts or I'd be living in the garden shed by now.) I didn't bother to document them here as I have some pride and didn't want this to end up being a "what mistake has jonboy made today?" thread. But, just to give a taster, there were a lot of "ah nuts, that's going to get in the way isn't it" moments.....

[Carmine A 3134]

@jonboy1 Glad to be back! 😀 Glad also, that this forum is still alive and kicking.... despite that the YouTube/FB Fanboys keep saying that "forums are dead". 

I'm so sorry that you haven't had a good year as well... 💔😫  I still miss my parents, lost both in 2012, within 33 days of each other, if anyone remembers.  Nobody could say anything to you that would make it all better.... but after a while, you'll start remembering the daffy things he used to do... and smile in the middle of the day. And nobody will have any idea why! 

To not lead you on.... as much as I would love even the main suspension bits from your kit. I don't think I'll be able to afford it for at least a couple of years. And I definitely can't afford a Brat kit in the foreseeable future....   But this whole idea really got me excited. I needed that after this year's financial catastrophe. Cheers!

[Carmine A 3134]

BTW.... the 2021 windfall had some merits... I was able to get:

3 brushless motor/ESC combos, 12 high torque all metal servos, a 12 channel radio for my foam aircraft (overkill, I know!)

A Super Clodbuster, a Blitzer Beetle, a CC-02, a M-05, a FF-03, a G6-01, two MF-01Xs and two TT-02Bs....

(EDIT: WANTED a Brat, a Hotshot a M-07, and a Sand Scorcher... but it was also the COVID nightmare, and they weren't available, anywhere 😕)

A Grand Hauler, a Globe Liner, a Mercedes 1850l Box Van, and 3 trailers....

Plus a truckload of paints, glues, tools, supplies and hop-ups! 

SO GRATEFUL I did, before finding out that my ungrateful step kids rifled through the rest of my inheritance. 🤬🤬🤬😭😭😭🤬

So yeah Jon.... I'm just carrying on, getting back to doing what I love. And occasionally..... some nice soul has even helped this old fart out with RC stuff! 

[NOT ANY OF THE PEOPLE who I spent almost $1000 each on, when I got the windfall. I was just so chucked, that I bought some things without thinking... and were obviously not appreciated.]  I'm over that now.

So let's bodge up some Tamiya!!! 😊

Edited October 23, 2024 by Carmine A
Just added...

[jonboy1 3754]

Ok, so the parts arrived and my lovely Mrs Jon said I looked like I needed a day to tinker, so I got everything together and started trying to put some of this stuff together.....

So, I didn't take any pictures as I was building because I've decided if I can't do build pictures that look as good as @toyolien's then I really shouldn't bother  Therefore: spoiler alert: It works!!!!!

Now, it isn't without its faults, so I'll start there before spending far too much time pointing out the good bits  

First, I somehow managed to get the width between the frame rails slightly off, by about 2mm, and in the wrong way, so the base plate ended up being too narrow. So I had to cut a couple of little spacer rails out of 1mm plasticard to pack it out. Had the same issue with the front bumper, which rattles in the little pockets at the front, so I put a little bit of plasticard in either side of that and it's now all good. I've gradually got some more parts building up for another project, so I'll get a new base plate printed to sort it out properly.

Attached to the base plate are the rear damper mount and the steering block. Also there are the pivot point frames for the cantilever arms for the front suspension, which also attach to the frames. The plan was that this would all bolt in as a sub assembly (with the servo, as it is actually used as a stressed member to support the rear damper mount) but as it was all a bit too narrow it proved kinda difficult to do. I think it'll all work much better when everything is the right size!  I also had a turnbuckle to act as a brace between the two towers, but didn't fit this as I was getting too irritate with it, but it will go on the final version.

This is the front end compressed. Somehow everything just misses everything else, including through the full steering lock!

And uncompressed:

I did make a conventional front strut tower just in case this didn't work,  but hopefully that can just stay in a parts box.....

The back end was surprisingly straightforward - I need to add a few shims here and there as there is a little slop, but that was expected due to the limits of printing. But everything fit really nicely, despite the mounting points for the M-06 transmission proving ridiculously complicated!

You can also see my new battery clamps  

and again, compressed:

And, as I know @Re-Bugged will be shouting this question:

Yes, the body fits over the motor!!  

So, what's next: Well, I am going to get the base plate reprinted and fit the servo and turnbuckle brace. I need to get a couple more turnbuckles for the steering as the ones currently fitted are slightly too short. Shims, as mentioned, just to tighten everything up a bit in the back. Then, with some radio gear it should be ready to test!!!!

I'm going to give the body a bit of thought. I originally planned to do it in near boxart (can't bring myself to put the pink on it) but now I'm looking at it, I think I have the seed of a cunning plan brewing......

[Andreas W 3016]

What I beautiful and technically brilliant creation. You have succeded incorporating modern elements and it is still unmistakenly a Frog. Hope it drives well with the current front suspension, since that is the most correct solution for an evolved Frog in my eyes. Having seenn this a normal front setup would be moving too much away from the original.