TOPIC:

Hi all,

First time poster, so please be gentle!

I finally got around to clearing out the loft a couple of weeks ago, to find my Madcap in a.n.other cardboard box. I had completely forgotten about it, even though it has survived at least two house moves and the majority of uni in the same box! It was a Christmas present in 1990, and I thought it was the Mutt's Nut's!

It's completely stock at the moment, and I reckon in not too bad a condition, so I'm thinking that I'm going to upgrade it a little (especially since I used to look at the 'optional parts' page in the manual and dream as an 11 year old kid!

Having looked around on this and many other sites, I've identified a few upgrades, straight off the bat (some have already arrived):
Aluminium Gear Plate,
Full set of ball bearings,
Ball diff internals,
CVA II shocks (front and rear), though not period - I saw the price of the HiCaps and thought better of it!

The tyres on it are bald as a coot, not that it bothers me in the first instance since I'll be mainly running on Tarmac (both as a kid and now), but maybe, just maybe if it goes fast enough I might take it to a track? Annoyingly I've got one (new) front and one (new) rear tyre! Goodness knows where the other one of each has gone!

I also managed to find my old 1400mAh NiCd and ProPeak 2500 charger, and my experiments have led me to deduce that after 20 years of not playing with it, a few deep cycles have got back to 1200mAh capacity, albeit at an average voltage of 6.9v. So I'll probably need a new battery. While I'm at it, I'm thinking of getting an ESC and a better motor...

Well, if any of you have any hints, tips or spare parts, I'd be glad to hear about them!

Ill maybe get some pics up soon...

Cheers!

Welcome on board chap

I've got to admit, while I knew that Tamiya made a car called a Madcap, I had to look at the manual to see the specs ... I don't see why it wouldn't be a reasonably capable RWD buggy once oil shocks are fitted ... what it does have (unusually for an entry level buggy) is a lot of gearing options - so as far as motors go, I would say the world is your oyster, or any other shellfish associated with planetary domination

The question is, how fast to you want to go? A Tamiya Sport Tuned motor (23 turns) will add about 30% in speed, a 21T Technigold motor would be a "period" upgrade (but will be disproportionately expensive), another option would be a more modern 19T motor, something make by Orion for example, adding about 40% ...

ESCs for any of those need to have the same "T" number or lower - e.g. a "20T" ESC is fine for a 23 or 21T motor, but not a 19T motor...

Batteries - NiMH have surplanted Ni-Cd packs, capacities are much greater (which means longer run times) - I'd recommend vapextech.co.uk (look under "High Power Model Control Batteries Sub C size") - the "7.2v RX Power Pack Rechargeable Batteries 3700 mAh " is IMO the best balance between cost & capacity ... You'll be able to carry on using your charger BTW



Faster still would be a brushless motor & ESC, Lipo batteries & charger - I'm not sure that would be a great idea with 20+ year old plastic, but it is an option

Thanks for the quick advice, much appreciated. I'm just looking forward to stripping it down, cleaning it up and getting it all back together!

The body shell is in good nick, but the paint is cracked in a few places, so I was thinking of 'respraying'; any tips on how to remove the original paint?

Thanks again!

Welcome man.
I have a mad cap. It was my first building. The first hopup to mount is the ball bearings and the metal gear plate. I broke the plastic version with a soft modified motor. Mine has bearings motor plate and grey alloy dampers (egress ones I think). It is a very good car relatively easy to restore. My dad mounted a lead weight under the front train. Better for the ride.

I've not managed to start the upgrades yet; still waiting on parts to arrive from Hong Kong

However, I've added to the treats that will be arriving, with some Astute universal joints and I managed to find 3 pairs of new original front tyres from a French supplier; get in!

But I have more questions for you all, if you would be so kind!

I'm looking to get a LiPo battery and charger, as well as an ESC to replace the MSC currently installed and a new motor. Jonny Retro has already suggested going brushless, which I like the sound of! I've noticed this combo (Combo B6) for an amazing price - £60,

www.hobbywing.c...asp?id=252

Basically, is it any good? Bear in mind it's just for running around, not for anything serious at this stage! It comes with a 9T 4300Kv motor, and a 60A/380A(!) ESC. Now, my problem is that it looks as though the Madcap will only accept round stick pack LiPos, which seems to limit capacity to around 3300-4000mAh, and 30C is the best I've seen; anybody else know of higher capacity packs that would fit in the vintage Tamiya round battery compartment? 30C @ 4000mAh; that's 120A continuous discharge; do you think this will be good enough for this brushless setup? What sort of run time might I expect; too short to be useful? The website doesn't mention current draw of the motor itself, only the ESC capabilities.

Obviously gearing will come in to play too, so have you any suggestions?

I've also seen the IMAX B6AC for a LiPo charger, seemingly great value! Is it any good?

Thanks for any help, guys, and sorry for all the n00b questions!

I said brushless was an option - but I still don't think I'd recommend it, 20 year old plastic may not be up to just driving around, let along hitting anything

The IMAX charger is fine - but make sure you get a genuine one (copies are a lighter blue & not necessarily cheaper - check out hobbyking.co.uk, they sell both sorts) ... the drawback with them are the same for just about any Lipo capable charger (most have the same 4 button setup & software) - they're fiddly to set up especially if you keep changing battery type (the also handle Ni-Cd and NiMH, and need a 12v power source (car battery, expensive RC transformer, or a hotwired old ATX PC PSU will work).

I have a Hobbywing 9T combo in a Bigwig, run times (on 8.4v 3700mah Nimh) were about 15 mins IIRC, speed was ok but not too manic ... if you want to set your trousers on fire you need the 5.5T combo

Gearing, from looking at the manual & assuming you have the 70 tooth spur gear fitted, if it were me I'd be looking at a 20 tooth pinion for the 9T combo (pitch is 0.6 module, or "AV" as Tamiya refer to it), or maybe a 19T for slightly more acceleration but slightly less top speed.

I'd be cautious about the batteries - I don't think anyone here has even attempted to use stick Lipo packs in that chassis, so you need to triple check the size ....

Once again Jonny, thanks for the advice!

Brushless seemed like a good option because motor+esc were so cheap (compared to Tamiya items, but I guess you get what you pay for)!

What to do, what to do!

Welcome aboard don't forget to load some pictures so we can see you rebuild

Whoops, it's a 13T/35A combo in my Bigpig the 9T combo will be quite a bit livelier with somewhat shorter battery run time.

Yep, a cheap brushless combo is attractive on price, vs 40 to 50 GBP for a basic brushed motor & ESC, and more like 80 GBP for something a bit better ... as for reliability, I don't know of any issues in use - but there are some reports of DOA units & others blowing up the first time they're switched on.

Well, I finally got all the parts and got stuck straight in. So quick in fact, that I forgot to take photos! sorry about that!

My first annoyance (and I can't believe it didn't spot it before I bought everything), was that one of the C1 parts was sheared in two and was being held together just by the screw pin! Suspension problems! Upon disassembly I also found that the two hexagonal spacers (part C3) were also sheared. This was going bad to worse.

I dragged it my trusty ultrasonic bath and stripped everything down to fit and gave everything a thorough clean. The hexagonal spacers did superglue back together (using some Loctite that I've always found good for Lego), but the C1 part wasn't having any of it. I've made a temporary fix out of some 2mm steel plate, bent in to a 'U' shape with appropriately drilled holes. I'm considering my options for a more permanent fix. There appear to be no C parts floating around eBay and the Madcaps that are on eBay seem to be overpriced (one on at the mo for £150!) any and all suggestions welcome!

But, everything else was spot on. I had a small panic when I saw the the Hobbywing 60A ESC didn't have a battery connector for my Acoms AR-227FE, but to my amazement, the receiver has the ability to take in power through Channel 2! Is that common?

I've started up with a 19T pinion, which gives me a gear ratio of 9.36:1, but after the best part of 30 minutes running (unbelievable runtime from the 4000mAh Lipo!) the motor was probably only 30degC. The ESC and battery weren't even warm. So I reckon I might be able to go up to a 21T for 8.47:1 and a higher top speed.

Which brings me on nicely to the speed. OH. MY. WORD. I know it is probably nothing to you seasoned pros, but it's now probably rocking 25mph if not more. It's a massive step up from the 12mph I measured when it was new (and stock). I certainly wouldn't want it to hit anything when a top whack, that's for sure!

So next on the purchase list are some rear hybrid spike tyres and probably some new wheels to boot, given that it will donut for fun if top speed is applied too quickly! It's all getting very expensive; but bloody good fun!

Cheers.