Turbo Jet Hopper Mamba Brushless Build Thread

[TA-Mark]

As promised work has started to fit brushless to a 'Toy' grade Tyco RC Turbo Jet Hopper.

Having received the buggy in yesterdays mail, I've since checked it over for completeness, all parts present except for 2 spot lights. I have 1 spotlight from my brother's wreck so will still need to hunt down one more or copy it in resin. (Yellow one from the front).

First thing to consider when taking a toy RC to brushless is the extreme rpm the driveline will now be asked to perform and the extended length of run time before a cooling break as cell technology has come a long way in 25 odd years. I Bet the engineers at the Tyco factory didn't invision their masterpiece being fitted out with serious amounts of power like this when they first penned it.

Step one for me in this conversion is to fit bearings to the gearbox shafts and gears. I started with the spur gear and mainshaft gear (same moulding). Originally this gear had a moulded bush, see Fig 1. (ie. none at all).

I removed 2/3 of the original bush with the dremel and a burr bit (you could also use a drill carefully). Sadly I needed to leave 1/3 of the bush behind as the 'L' gear is too small in diameter to be fitted with a bearing inside of it without making it too weak.

Next I cut a length of scrap nylon tube to become the new bearing seat. It's approx 9mm outer diam, 7mm inner diam and 6mm long. I then bonded this tube into the 'H' gear to where I had removed the moulded bushing from. Fig 2. & Fig 3.

Into the nylon tube I fitted two 730 bearings and bonded them into place. These need to be bonded as the whole assembly will slide up and down the mainshaft to change gear from 'L' to 'H', and you don't want the spur gear sliding down the shaft without it's bearings. Fig 4.

So the new revised spur gear/main gears now rotates on 1 bush and 2 bearings. If the 1 nylon bush that is remaining has problems I will need to fit a brass tube inside the 'L' gear or look at other options to use for gears.

Next is the rear axle. I need to wait for the right size bearings to get here to modify and complete that task.

Cheers, Mark

[gordb]

Dude,

This is what this hobby is all about!

I can not wait to see how this turns out =)

Cheers!

[sgt.barnes]

OMG jet hopper + brushless = childhood dream This looks like a build thread I will be watching. Nice one Mark

[TA-Mark]

A pair of 4x8 bearings are on their way from Hong Kong for the rear axle. The axle is 4mm and the bearing holder is ~8mm. Standard they used part of the wheel rim as the axle bushing. This will be as simple as fit the bearing and cut 4mm from the inside of each rim and fit a shim so the rim doesn't rub on the bearing sheild. This gearbox has been very easy to fit bearings to compared to the Nikko Venus.

I've been considering the body finish... As everyone knows I'm partial to Bright Yellow... What's everyone's thoughts? Standard black? The spare standard red body? Or some custom decals and 'TA-Mark' colour scheme?

[Mighty flex]

keep it looking completely original - then people wont know what hit them

[TA-Mark]

The local guys here gave me an ear bashing when I suggesting painting the TJH. "Don't mess with the look", they said, "It's an 80's Icon". "Don't make anything appear modified on the outside of the car at all, only the driveline and electrics." It will be black, unmodified to the eye until it moves (They'd string me up if I did it different). I will paint up the red body in yellow (it's badly faded). They were all cool with me doing it to that body as it was already damaged.

[TA-Mark]

I would really like to see a gloss yellow Jet Hopper with original (reproduction) decals. Yeah I'm not really one for visible modifications myself.

Glossy Yellow with 3 colour metal flake just like the DF-03 MS and F-150. A yellow one would fit in with the rest of my buggys nicely. Original repros stickers will be easy as they were printed on white 'paper' originally. Black body for when it's not being used and on show.

I've been testing the original radio gear and it appears to be faulty. Runs for about 15sec then dies. You then need to wait 1/2hr-ish for it to work again. I don't feel so bad now tearing up a 'good' TJH in that it doesn't work in original form.

[davegsm82]

Hi Mark,

Very interesting thread, i'll be starting my own thread very soon about ressurecting a Jet Hopper II Turbo from about 1989 which I had as a kid.

Unfortunately i've lost the handset which has really annoyed me as I wanted it to be as original as I could get it within reason. Because of this i'm going to have to fit some radio gear, new steering servo etc that will work with the chassis.

Can you tell us what motor you're fitting? i'm new to Brushless motors although i'm well practiced in the theory, but all the ones i've seen are about RS-540 sized which is a bit big for the gearbox.

Cheers, Dave.

[Butler]

Probably something like this:

http://www.castlecreations.com/products/mamba_micro_pro.html

[TA-Mark]

380 will not fit. A 300 can from a RS4 Micro will. The Castle Micro CM20 motors are not 380 size, 200 if I'm not mistaken.

Run the standard motor on 9.6v for a few minutes under load and it will burn out (BTDT). The receiver doesn't use the full 9.6v of all 8 cells either. The limited range is testiment to that.

I just bought an almost new Nikko Venus from the UK. Cost me a massive 2.20 GBP, the postage was more. I'll get a video comparison up soon between a completely stock buggy vs the Mamba25 powered one I've modified. The difference is almost unbelievable.

[Live Steam Mad]

Any updates Mark? I'm enjoying your build immensely. Love to know what brushless system you have in mind to buy at the moment. Sounds like a very exciting project, I'm kinda obsessed with the Jet Hopper Did the new bearings arrive for the gearbox?

Cheers,

Alistair G.

[commiedoor]

what ever happened to the hopper mark ?

[TA-Mark]

what ever happened to the hopper mark ?

It was fully ball raced, made to work and then shelved as I worked on other projects and have just not gotten back to it. The rear tyres are shreaded after a few runs. They were pretty perished to begin with so didn't last very well. Finding good condition replacements isn't easy.

It's up to painting stage like many of my other builds.

[Wild Willy Speed Shop]

That race in Punky Brewster was an awesome Tamiya add. haha

[Jason1145]

What happened to this???