Tonka Winnebago RC Project

[PraetoR]

'lo all.

 

Inspired by @walkbythesea's HPI Venture Tonka Winnebago project, I wanted to do my own.

 

I got this for Christmas 2021 and have been sort of picking away at it, throughout 2022. I've been craving a build, so now is the time to properly tackle it!

 

My aim is to have a reasonably capable trail truck and I'll be spending as much time and effort on the interior as I am on the mechanicals.

 

I want it to look DISGUSTINGLY '70s! 

 

Anyway, I don't have any pictures of the Winnebago, intact... so, instead, here is a video I made a long time ago (you don't have to watch this):

 

 

 

Since then, I've decided to use my old Gmade GS02 Komodo chassis as the basis for this project.

 

First thing I did was try to address the track width, as a standard trail truck is too wide for the Winnebago. Certainly, if you want the wheels and tyres to tuck into the arches, which I do. Secondly, I needed something heavy, as the Winnebago is made from steel and is a hefty girl! A smaller RC, such as the FTX Outback is fine, size-wise, but is very flimsy and very light. The donor chassis must be strong. Hence, the GS02.

 

Anyway, the Gmade axles are too large, so I decided on the Boom Racing BRX90 Phat Axles. These are fully metal, so are fairly heavy. They are also well machined and plenty strong. I figured the BRX90s would be ideal, width-wise, as I reckon the BRX70s are a little too narrow.

I also bought Boom Racing knuckle weights, front and rear, plus additional weights to bolt onto the front knuckle weights, further increasing weight (and forward bias). The front end took a bit of trial and error to get the panhard bar, shocks and front links sitting right.

 

The GS02 uses counter-rotating driveshafts, to reduce torque twist. As standard, this causes the front BRX90 axle to spin backwards. Luckily, Boom Racing sell mirrored bevel gears, for just this reason.

 

An increased wheelbase of around 330mm is needed, but I decided to keep the front links at standard length, only increasing the rear. Means I don't have to muck around with steering geometry, etc. Also, I already had nice, heavy, front stainless steel Gmade links.

 

 

 

I made longer rear links, using m3 threaded rod, sleeved through aluminium tubes with 3mm inner diameter. The resulting links are much stronger than I expected. In-fact, I'm really pleased how they've come out! They are perfectly matched, left-to-right, and the axle is absolutely dead straight. 

 

I had to move the rear shock hoops back, by two holes. It looks good. Happy with how they are sitting.

 

 

 

Front knuckle weights, with extra weight bolted onto them. Pretty serious stuff.

 

 

 

They JUST clear the wheels! Good thing I'm also using Boom Racing wheels.

 

 

 

Very pleased to discover I had some stainless steel driveshafts, just sitting in one of my spares' boxes. They turned out to be just the right length!

However, here is bad news part 1: The front one has the little pin with e-clip missing, so I can't connect the universal joint! 

 

I've hunted. For some reason, I don't have it.

 

This is a real shame, because I could have had a completed rolling chassis.

 

 

 

Bad news part 2: The rear knuckle weights are supposed to fit these axles. They don't.

 

You have to screw four grub screws in through the weight and into a locking ring, which squeezes the locking ring (bottom of the picture) onto the axle. This doesn't work. I've tightened them as much as they'll go (to the point that the grubs screws strip) and the weights still slide on and off the axle, with no resistance. They aren't even close! I wonder if they've sent me the (very similar looking, but non-compatible) BRX70 rear knuckle weights.

 

 

 

Anyway, I've emailed Boom Racing. We'll see what happens. In the meantime, I've continued without the rear weights.

 

 

The wheels are PERFECT!  Love them!

 

The Gmade MT1903 tyres are too big, but I already knew that. These are just for testing, as they're all I had. They are ~110mm high. I expected to buy some Gmade MT1901 tyres (as seen on my HPI Venture), which are 105mm (and have an awesome tread pattern), but even these may be too big, looking at the Winnebago arches; bearing in mind, I'm trying to get the wheels and tyres to tuck under the arches. Boom Racing do some nice looking 97mm tyres, for a very reasonable price. Hmmmm...

 

 

 

Black diff covers will need to be ordered! Can't be doing with the bright red!

 

 

 

This photo shows off the extended wheelbase.

 

 

 

Drilled-out the six spotwelds that held on the Winnebago axles.

 

 

 

Sits too high. It's sitting on the shock hoops. This needs addressed, but I really want to keep the interior intact, so I'll have to figure something out. Perhaps home-made, shorter shock hoops and shorter shocks (or cantilever suspension)?  Thinking to be done. The motor and mount will need to come through the floor, but that's OK, because they'll be under the table!

 

Speaking off shocks; I'm very impressed that the Gmade units managed to put up with the weight of the winnebago, even when I threw the roof parts and interior back inside it. I expected them to instantly compress, but they don't. It actually floats pretty well! Stronger oil will be needed, though.

 

As stated previously; the tyres are too large.

 

 

 

If the body sat down on the side plates, I reckon that would be pretty spot-on.

 

 

 

Yuck! Red diff cover!

 

Also, since I bought the BRX90 axles, Boom Racing have released the BRX80 axles, which are 14mm narrower. This is annoying, as the BRX90 axles appear to be approximately 14mm too wide!!

 

If the BRX80 axles were out at the time, I would have bought them. Actually, I'm considering buying them, although they are pretty expensive and the similarly-expensive BRX90s are brand new, unused!

 

 

 

Yeeeaaahhhh... 7mm either side... that would be pretty much perfect.

 

Should I?

Shouldn't I?

 

 

 

Anyway, this is where I'm up to, Thanks for reading. 

 

Any advice would be greatly appreciated and sorry for my crappy phone pictures... my phone was the base model... back in 2015! 

 

Cheers!

Edited January 17, 2023 by PraetoR

[Stormbringer]

awesome mate gonna watch this thread with interest 

[Shergar]

I remember the Tonka video, I’m rather taken by your conversion.  I’m doing a similar project (but using TRX4 axles) and have used wide rims reversed to get the desired effect - just a thought? I see your rims don’t have a lot of offset already however, so not a massive gain.

Shock hoops? How about these bolted the chassis instead?

 

https://www.ebay.co.uk/itm/402769162371?hash=item5dc6e9b083:g:-HUAAOSwAktgYaxP&amdata=enc%3AAQAHAAAAoGb74lHXIbsfWeEu3nsPaDDKSXI2B6CeR0yobSA8K592fzKPq2FkkDhqhfSC%2Bfkd4TQn7fAiiIU%2F0f%2FsVFGzMSBPWj6wT0GWFlwtTxoVxZSL5Qx0c%2BtnO8ZsjENN16k5nCzFabFJeM640PTjn2UGh4%2F1Mi5bO0KejZBRyQyVkLep%2BYA06QRHclGGnzAIJesSZNWtx7RsuRs1qH7aWxZg9yk%3D|tkp%3ABk9SR-6D36O4YQ

 

 

 

[Lone-wolf]

nice build, look forward to seeing how it runs

[PraetoR]

Aaaaaand I've just spent a tonne of money! 😩

 

But I guess it's OK, I'm getting a wage rise. Many interesting things enroute!

 

 

 

21 hours ago, Stormbringer said:

awesome mate gonna watch this thread with interest 

 

Thanks. I'm hoping to do the concept justice.

 

 

20 hours ago, Shergar said:

I remember the Tonka video, I’m rather taken by your conversion.  I’m doing a similar project (but using TRX4 axles) and have used wide rims reversed to get the desired effect - just a thought? I see your rims don’t have a lot of offset already however, so not a massive gain.

Shock hoops? How about these bolted the chassis instead?

 

https://www.ebay.co.uk/itm/402769162371?hash=item5dc6e9b083:g:-HUAAOSwAktgYaxP&amdata=enc%3AAQAHAAAAoGb74lHXIbsfWeEu3nsPaDDKSXI2B6CeR0yobSA8K592fzKPq2FkkDhqhfSC%2Bfkd4TQn7fAiiIU%2F0f%2FsVFGzMSBPWj6wT0GWFlwtTxoVxZSL5Qx0c%2BtnO8ZsjENN16k5nCzFabFJeM640PTjn2UGh4%2F1Mi5bO0KejZBRyQyVkLep%2BYA06QRHclGGnzAIJesSZNWtx7RsuRs1qH7aWxZg9yk%3D|tkp%3ABk9SR-6D36O4YQ

 

 

 

 

That's certainly a good idea. I did consider it; the wheels I'm using can be reversed, but it only reduces it by 2mm and ruins the look. I need more than that. It's OK, though... I've found the solution!

 

Thanks for the link. I'm still working things out for the front suspension (I know what I'm doing with the rears).

 

 

15 hours ago, Lone-wolf said:

nice build, look forward to seeing how it runs

 

Thank you. Hopefully, it doesn't disappoint!

[Shergar]

Everyone loves spending money 😂

[PraetoR]

Made some more progress on the Winnebago. Basically, a big order from Boom Racing. 

 

First of all, I managed to get the rear knuckle weights clamped onto the rear axle. You have to give it some major yeehaw... so much so, that it cost me a hex driver (pictured).

I'm a fan of Boom Racing products, but this design is not great. Nevertheless, it's done.

 

 

 

 

Converted the BRX90 Phat Axle into the BRX80 Phat Axle, using the conversion kit. This was an expensive solution! I wish the BRX80s were available when I started.

This has left my servo arm too long. I'll have to make changes.

 

Ordered the black diff covers, which are a MASSIVE improvement! If I was in-charge of Boom Racing, the black covers would be standard and the red ones optional. I'd put money on more people preferring the black!

 

 

 

 

 

 

Ordered the Boom Racing Gekko all-terrain tyres. These are beautiful! Lovely, soft compound. Seem super sticky. Great-looking tread, too. 

Also, at just 97mm OD, they are marginally smaller than the Gmade MT1901 tyres, which I was planning on using.

 

Combined with the Boom Racing beadlocks, they have the exact sort of "offroad truck with steel wheels" look, I was going for.

 

 

 

 

Boom Racing "BADASS" (the actual name) Heavy Duty steel centre driveshafts. MUCH nicer than the generic driveshafts I had in-stock! The rear was very marginal on length, but it has just enough clearance, that the rear suspension can fully compress.

 

I was worried about the front (from the very beginning of this build), because the original Gmade GA44 front axle had an off-centre pumpkin, which is why the front gearbox output is to one side. With the Gmade axle, the front-centre driveshaft is straight.  I wasn't sure having a centralised pumpkin, driven off an off-centre gearbox, would work. I know Universal Joints will allow a driveshaft to turn at a different angle to them, without binding. That's the whole point. However, I was worried that asking the UJs to be at a constantly-changing different height and angle, simultaneously, would cause issues. I needn't have worried. The angles are not at all extreme. It works smoothly, with zero binding.

 

 

 

 

The Winnebago sits a little lower, with the smaller tyres. Ground clearance should still be fine, as the Phat axles have small diff pumpkins. In-fact, these axles with 97mm tyres have more clearance than my HPI Venture axles with 105mm tyres (thank God, because my Venture's ground clearance is shocking!). They look the part. Very happy with the Gekkos.

 

 

 

 

Slightly misleading angle, as the front of the Winnebago is closer to the camera than the tyres; even still, you can see that's a much closer track-width.

The BRX80 axles were the right choice. 

 

 

 

 

Oh, yeah! That's better! 

 

 

 

 

 

 

 

 

The 97mm Gekko tyres are the perfect fit into these wheel arches. This is exactly what I wanted!

 

 

 

 

 

 

Gmade parts and electronics en route, as well. Looking forward to making some big progress.

 

I've got a 40kg servo. It looks and feels nice, but it's an Amazon special... so it's probably only about 15kg! We'll wait and see.

 

 

Edited January 31, 2023 by PraetoR

[Stormbringer]

Really making progress now mate and looking great 

Edited January 31, 2023 by Stormbringer

[PraetoR]

IT LIIIIIIIIVES!! 

 

OK, the electronics need mounting, the servo arm needs attached, the battery needs repositioned, the suspension needs altered and the chassis needs to be attached to the Winnebago, but...

IT LIIIIIIIIVES!!

 

 

 

[Stormbringer]

Woohoo making progress mate 

[Shergar]

The suspension seems a bit hard if its cocking a back wheel! Or will it behave with the weight of the body?

[PraetoR]

41 minutes ago, Shergar said:

The suspension seems a bit hard if its cocking a back wheel! Or will it behave with the weight of the body?

Yeah, pretty sure that's the case. These are the same shocks and springs I used to run on the Komodo and they worked well.

 

There will be a lot of fettling required!

[BashingBrian]

This looks like a pretty cool project you've got going there 😎

Look forward to seeing it progress..

[PraetoR]

Bit more progress on the 'bago.

 

The latest task was to sort-out a rear suspension setup that would allow the chassis to be mounted without cutting holes in the floor of the Winnebago. The shock hoops are just too high.

 

Luckily, the GS02 chassis is also available with the BOM Trail Truck, which uses a different rear shock solution. This is the route I wanted to go down.

 

 

 

As standard, it's a cantilever system, but this wouldn't work. This is because the cantilevers have to be mounted behind the rear axle; and with the longer wheelbase, there simply isn't enough chassis left. A longer chassis (or an extension) would be needed.

 

Luckily, the BOM also has the alternative "V-configuration". This includes mounting the shocks upright, but leaning inward, with the tops attached to the chassis braces. It's incredibly effective at controlling the truck mass (something the Winnebago could definitely use), in-fact it's so effective, that the GS02 BOM RTR has the V-configuration fitted from the box.

 

 

 

The good news is, the little plastic mounting block that's necessary to use the V-configuration is not only included with the BOM kit, but it's also included in the Komodo kit!

 

 

Now, the Winnebago is going to be a damn sight heavier than a BOM and I noticed the plastic brace has a bit of flex. This brace literally has the entire weight of the back of the truck suspended from it, so an upgrade to the metal brace was on the cards. 

 

 

Plastic brace (between the shock hoops).

 

 

 

 

The metal brace is very nicely machined and MUCH stronger.

 

 

 

 

The all-important shock-mounting block.

 

 

 

 

Had to stand-off the shocks a bit, but they are solid.

 

 

 

 

The BOM rear shocks would have been too short, as the mounting holes on the Boom Racing axles are further away, so I bought these lovely, longer Gmade RSD shocks. It was pure guesswork! However, the length is almost perfect. 

 

 

 

 

It sits really nice.

 

 

 

 

Rear clearance achieved! The front will be more of a challenge, but progress is progress.

 

 

 

 

 

 

99% sure I'm keeping the front shock hoops and suspension, so I moved the threaded rod from the rear, to the front. The front shock hoops had alarming flex. They are now solid.

 

 

 

 

The V-configuration was supposed to give more control over mass, but reduced flex...

 

Less flex, my backside! Look at it!! 

 

 

 

The shocks sit nicely, even under the weight of the Winnebago. Very happy how this has turned out.

 

The front is next. As is finding a new battery mounting location (I've got another idea). It's going to be tricky, but she's getting there. 

 

Edited February 28, 2023 by PraetoR

[Stormbringer]

that really is neat solution nice 1 mate 

[walkbythesea]

Looking really good 👌

I'm excited to see this coming together for you, hopefully we can arrange a great dirty 'bago meet-up and drive out when you've finished her 👍

[Kpowell911]

That’s amazing! I really admire projects like this. 

Edited March 1, 2023 by Kpowell911

[Stormbringer]

yeh he is doing a good job on it 

[PraetoR]

Cheers, all! Appreciate the support. 

[walkbythesea]

How’s it coming along?

[walkbythesea]

Any progress?