Doom & Gloomerang - Boomerang RestoMod

[Hobgoblin 1059]

A slow burning project that I've been interested in for a while but have only just started to make tangible progress on. 

The basic idea behind it came from really liking the old school Tamiya 4wd cars, I own a manta ray which I have really enjoyed working on and I have come to appreciate the even older designs whilst working on my Falcon.  The Boomerang is also a very attractive car in my eyes, the sleek body with the wing swooshing skyward is excellent, plus I want to try a monoshock car for the novelty of it all. Whilst the box art is rather sweet I wasn't overly taken with it, when I'm not collecting specifically I'd rather do my own thing. It allows a lot of deviation from stock to be justifiable to me. Odd perhaps. Anyway I felt like going a bit angsty and moody, I think the body will be very dull and dark. I will be ditching as much of the blue and yellow as possible to keep with the muted palette.

I stuck up a wanted ad on here some months ago and @toyolien obliged with a scorching deal! 



A rather splendid example with a busted front end. Other than that it was very serviceable. I quickly found some replacement front arms on ebay for pocket change. If they break still I will buy a re-re parts tree.



I toyed with the wonderful factory works chassis for this, but I just cannot afford it at this time. So, I have broken out the crayons and have been designing my own. I think a folded aluminium C channel should do the trick (whilst mimicking Hot Trick stuff!) The bare metal will also fit in nicely with the intended colour scheme. 



^^ CAD very much a work in progress

First off I stripped the car down and did a basic clean up and stock take on what needs sorting.



just a toothbrush and washing up liquid but it makes a badword of a difference.



Like all builds, bearings are an absolute necessity, I am running rubber shielded on the outside. (partly due to what i had in stock)



These blue parts might go at some point. Maybe through paint. Depends how visible they end up being. 



Luckily everything was just a little dirty, everything was clear of cracks. 



Gearboxes were equally grubby but ran really smooth, even with bushings.



Tiny, horrible clip that immediately broke as I removed it. I will replace it with a E clip or perhaps a tiny circlip (US: snap ring?) if i can get the width matched. 



I did a bit of pointless decoration, I filled in the 4WD moulding with a paint pen. Not particularly well but I can tweak it later.  These little details are what makes Tamiya stand out. 

I printed a mockup to check the dimensions of my model, so far so good. I have a full reel of filament loaded and will be overnighting the next version of the frame. 




I have a decent stockpile of parts to continue working on this but am still trying to decide on an acceptable power plant for this car, I am undecided whether to go brushed or brushless. Shorty lipo is a definite, however and I will be changing up the steering. 

Thanks for reading!

H
 

[toyolien 4679]

Ohh that's looking good. Definitely subscribed to this one 

[Mad Ax 9312]

interesting concept...  I will watch this one, I love a non-boxart build  

[Hobgoblin 1059]

Not very gloomy, but here's a test chassis in eye searing green!



Had to split the print in half to make it work with my ghetto setup so its not very pretty in the middle but it does the job. The centre distance for the driveshaft is okay. On that note I finally decided to bite the bullet and buy the hotshot prop joints. I had the shaft which I grabbed for a fiver a while ago. Obviously this will be the same length but I'll be test fitting that when it arrives. I will continue working on the battery mounting once I have parts printed to check everything clears the driveshaft okay.



Checking motor clearance with a burnt out sport tuned (which I absolutely refuse to throw away since the black cans are OOP, no matter how bad it smells) The wire gap is enough to fit 3 wires & a sensor cable if i do go brushless. I'm still not sure what I want to do with that. Either brushed or sensored brushless. I have some 13.5t motors which fit the theme well (not bright pink/red/blue) but I don't have any sensored escs. The cheap £13 ebay jobs might be my best bet but that's at least a months wait at the moment. Might have to pick up a tble-02 as they're fairly inexpensive and often UK based. Once I have those parts locked down I can work on mounting as I'd like to be a little belt and braces with that regard. 
 

[Hobgoblin 1059]

I did a test fit of the arms and fitted out the gearboxes with bearings. Only part i'm stuck on is the thrust bearings but with the help of a little Shenzhen magic (not a joke over the current tragedy unfolding) I have something that might solve it.



I also broke out the wheel & tire combo I'm wanting to use on this car

 

With tire writing because I've become one of those people.

I have roughly designed a front bumper which is being printed currently. Still have the hassle of sorting out the steering and drawing up a rear shock tower. 

[ThunderDragonCy 7877]

Looks mega! 

[Hobgoblin 1059]

Thanks! 

The chassis has acquired an odd, bumper shaped growth on the front of it. Now aluminium shares absolutely none of the qualities required for being a bumper for a brittle old RC car but I think it looks rather cool and it supports the front gearbox. Maybe if it ever bites me in the asp I will change it to a plastic one.



A few hours of printing later I had another test chassis






Quite proud of getting the spacing and the angle fairly spot on. 



Oh, and the hotshot prop shaft is installed as the prop joints arrived today. Very pleased with that, it feels much more sturdy than the stock coathanger. 

[ChrisRx718 4470]

Very cool. Glad to hear you are keeping the monoshock - I think that's the defining feature of the Boomerang but I understand the performance benefits of binning them in favour of dual shocks.

Is the green prototyping or will the final version be as eye-popping?

[Hobgoblin 1059]

I am definitely keeping the monoshock. Like you say it's a defining feature and if I wanted a car that really performs, I wouldn't be building a boomerang! 

 

The vibrance of the chassis is slightly ironic as I'm going for grey and gloomy. I just happened to have the green loaded in my printer. The final one will be aluminium, so silverish when done.

Cheers!

1 hour ago, ChrisRx718 said:

Very cool. Glad to hear you are keeping the monoshock - I think that's the defining feature of the Boomerang but I understand the performance benefits of binning them in favour of dual shocks.

Is the green prototyping or will the final version be as eye-popping?

 

[Busdriver 6209]

On 3/21/2020 at 7:32 PM, Hobgoblin said:

I did a test fit of the arms and fitted out the gearboxes with bearings. Only part i'm stuck on is the thrust bearings but with the help of a little Shenzhen magic (not a joke over the current tragedy unfolding) I have something that might solve it.



I also broke out the wheel & tire combo I'm wanting to use on this car

 

With tire writing because I've become one of those people.

I have roughly designed a front bumper which is being printed currently. Still have the hassle of sorting out the steering and drawing up a rear shock tower. 

Love the Wheels

[Hobgoblin 1059]

The wheels are excellent, I am wanting to get a pair in white for my Mock Force!



I was trying to set up the steering to try and I found a crack which quickly became a snap. Sad times. However technology is amazing and we live in the future so I was able to download & copy my own from thingiverse. I will post the link when i find it again. The model is perfect.



My trial steering is in place and seems to work pretty well.





Fully supported dual ball bearing throughout, and it still works with the stock steering hardware. I will have to wait until the car is running to see if its really any good at all.




I am pretty happy with how the front of the car is turning out. Although with the servo and battery in the orientation i want them it will be a tight squeeze. 



Cheap & cheerful low profile servo, I have a few of these in various things. Pretty quick and they have decent power - I hope they don't get discontinued with all the other car stuff on Hobbyking.



And there we see it all jammed in. I will be drawing up a combination battery retainer and servo mount soon I think. 

[Hobgoblin 1059]

Well, there's a Boomerang chassis nice and flat packed. I am looking forward to playing with it! I need to order some darker filament for the printed parts and I am finally running out of 1150 ball bearings. I will be ordering a repro body from penguin bodyshells soon I am still wondering what the best way to go with decals are. 



I was wondering how to colour the blue parts to remove any happiness or joy from the car's palette, after a bit of back and forth I settled to just do as a 10 year old would do and just rattle can it the colour I want



I plugged the bores in the rear hubs with bushings (finally a use for them!) and this worked quite well. I busted out some kobra grey spray paint and gave it a few coats. Pretty pleased! We shall see in time if it flakes.







Pretty happy with the look! 
 

[Hobgoblin 1059]

Unfortunately I might end up scrapping the folded aluminium chassis for now due to all the belt tightening going on 

I hope to return to it though, maybe it calls for a hotshot build too and I can add some cage details and look into some funky anodising. Gone but not forgotten </3 

So with this in mind I have been working on something a little cheaper to make and easy for me to produce at home in the spare room 



Here is where I'm currently at. The carbon may stay or go, but it looks rather nice and adds some contrast to the generic grey blobs I'd be otherwise working with. This is a couple hours of spitballing thrown up into a semi coherent design. I *******ised my initial sketches and thickened a lot of it up so as to be useful once printed. There will be a lot of tweaking to come as I'm happy with the concept but unsatisfied with the detail. 

[GTodd 1346]

Wait are you making all of your parts? I really need to get a 3D printer! Nothing like being able to make your own spares!

[Hobgoblin 1059]

10 minutes ago, GTodd said:

Wait are you making all of your parts? I really need to get a 3D printer! Nothing like being able to make your own spares!

Yes I do all my own printing. Shapeways is an excellent service but too rich for my blood. I built my first printer about 5 years ago now and it was basically a hot glue gun and some stepper motors, lots of Heath Robinson arangements later I had something that produced fairly decent parts in PLA. However my hobby at the time was Robot Wars which is a bit violent and the prints I could produce were not strong enough. Later I was an R&D engineer who handled all the prototyping, we had a very respectable machine that could work in more materials and had fairly high quality in ABS. I borrowed time on it where possible and when the company closed its doors it just happened to follow me home. Quite haggard now but it happily churns out RC projects for me and scares my rabbit with its whirrs and beeps. I am always happy to produce parts for anyone on TC if they give me an STL or a dimensioned drawing. 



A few hours later and quite a lot of beer. I modelled my servo and the hardcase Lipo and tweaked some dimensions after I had found my test print had finished. I feel a headache tomorrow morning though.


 

[Problemchild 2149]

Looks awesome - why not stick with your 3D printed chassis? You could add some strengthening or make it in the 2 ends you have with gorgeous shapes side panels with tamiya logos embossed

JJ

[Hobgoblin 1059]

The printed chassis I had before was 2.5mm, which is pretty thin for printed stuff.  Lots of flex isn't great for a chassis, plus it had to be printed in at least 2 parts in sub optimal orientation, would be like driving a car made of glass and paper mache. Better to design one specifically to be printed and save the work on the aluminium for another time. I love your idea for embossed logos @Problemchild I think I will be including those on the battery retainers at least!
 


The postman was kind today, bringing me lovely china thrust bearings. I think these worked out to just under a pound each.



Pretty happy with the fit! Very smooth now.



Trial print to get my geometry right. The tollerance for the ball joint was spot on screwed in no problem. I will be adapting the counterbore so it won't have a failed wall (part designed thinner than the printer could produce so it skipped it)



I am pretty pleased I managed to get the shape of the boomerang part fairly close. I had to recess it as the new thicker walls of the print would have pushed their mounting points way too wide for the sway bar. Simple 3mm dip and they're sweet.



I will probably stop revising this until I make up a baseplate to test it all on. I am thinking HIPS, balsa wood or plasticard sheet. Something very easy to cut with a knife



Placeholder ESC but you get the idea. I think the layout will be functional. I have new rear shocks on order. Sadly just black china aluminium ones as I can't find any black CVA long enough.  They were £3 each so it is not a crying shame if I end up chucking them.

In good news I have run out of lurid green ABS so we should see some nicer colours soon 

Thank you for reading

H

[Ferruz 11702]

Nice project man!! And... I loved that lurid green! 

[Hobgoblin 1059]

I am currently printing in black at last but in some horrible cheap filament, lot more finicky to get it to work than the expensive branded stuff. 



Battery blocks which may get trimmed down as they are a little less meccano and more building block than the rest of the build. Two screws each hold them to the base. These are being mocked up as I type.

I have ordered some goodies. Lots of threaded rod, some aluminium tube and most importantly a HIPS sheet for chassis mock up. 

[ruebiracer 1046]

Great project, fun to follow. For your power plant i can really recommend using a sensored 13,5t Motor from your stock, and Combine it with the TBLE02 Tamiya ESC.

I used it last year on Tamiya Euro raceway in my Vanquish, and the power was just right for an old vintage (Tamiya) buggy. Very good to handle, not being silly fast or too slow for a big track to be boring… . The kit ESC really surprised me positive running on brushless. If Tamiya ever realizes, that everone nowadays uses Lipos and not LiFePo and adapts the low voltage cutoff value, there is now Need to buy an extra ESC for many models. But so far I just use an extra Lipo warner for comfort.

Kind regards, 

Matthias

[Hobgoblin 1059]

I have a nice 13.5t actually, it is a completely black can. I could stick a repro motor label on it (dyna tech, sport tuned etc) might be neat. I will try and keep an eye out for a cheap TBLE-02. Thanks for the suggestion!

[ruebiracer 1046]

That´s exactly what I had in mind, I have a speed passion Sportsman for 20€, which looks like a normal silvercan. With a TBG Dynatech 01R repro sticker, I faked a nice "silver dynatech 01R", inspired by the new silver "sports tuned" version. If you have it in a black can, even nicer! May I ask, where you got the motor from?

 

[ruebiracer 1046]

Even Tamico has the ESC new quite cheap nowadays, probably from opened kits:

https://tamico.de/Tamiya-Fahrregler-Brushless-Brushed-TBLE-02S-ohne-Sensorkabel

But should be available in UK, too.

[ruebiracer 1046]

Here a Little inspiration of my ongoing Avante 2001 runner restoration:

[Hobgoblin 1059]

That's such a beautiful car @ruebiracer 10/10.  Love the colour too.

The motor I have is a speed passion also (my personal favourite brands) it came with a chintzy silver and orange tribal sticker which quickly came off. Unfortunatly I don't know where they can be bought from as I got that one and a 10.5t (with silver and purple tribals) in a job lot.



It needs a clean quite badly. I am unsure whether to strip it bare and repaint it or let a sticker hide all flaws.

Yes you can pick up TBLE-02 for £16, I added one in my ebay cart this morning. Unfortunately I cracked my mobile phone screen whilst climbing inside some equipment at work. So that's a £30 fix which is the month's "Toy budget" oh well at least there are lots of options for them, being removed from kits frequently.  Worse things happen at sea!


Since I was having too many problems with the cheap black filament I complained and was sent some from a different batch. I reverted too what I have in stock. Some lovely pink. This gloomy car has the most ironic hotch potch of colours.