10 years after - the Black Widow (TRX1) still runs ;)

[Lonestar]

Hi guys,

I won't rehash the story again and again about how surprised one can be at the shape some "runners" are sold as... So I basically started rebuilding a TRX-1 from fresh parts, as I need it to compete in the last round of the vintage class in the SIORC - check it out here, for the pics, unless you speak french!

http://www.overrc.com/courses/courses2010/siorc23012010/siorc23012010.html

Right now I've done miracles with a Fire Dragon (slightly souped up and modded I must admit ) but it isn't a true racecar, and the rounds I won I won them basically as I can drive for 5mns without crashing, as opposed to my competitors, in that class at least... but I want to make a statement in the last round

The traxxas will be a true racecar as opposed to the FD... I call it "The Black Widow", I guess you can easily figure out why
Period electronics will be the rule, except for lipos (sorry, I can't stand niXX any more, just too much of a pita once you've tried lipos).

It's a build in progress, I will post pics as I go!

The main non-new parts in there are:
- chassis
- shock bodies-shaft-pistons
- motor plate / shock caps (anodization removed)
- bellcrank

Right now I've spent most of my time on the front end as I don't have the steering posts, so I used flanged bearings on M3 screws, I'm also missing the ackerman bar, and the front spindles aren't 2732... so it took quite a bit of fiddling to get the geometry right. I'll start the rear end soon, then the rest of electronics:
- Brand new KO EX-1 or used Caliper 3PS , not sure yet
- 410MXC I think (although I have a 411P that I've always wondered about )
- some kind of 15 turn motor, still TBD, I'm thinking the LRP "Big" series...

Basically it's only the beginning of the journey



Some of the parts (a lot more non pictured )



Front end partially assembled, rear end basics bolted on chassis:



Front end almost done, still some stuff to fine-tune:



Front end completely done, top view:



Side View (with brand new period PS713):



A pic of the mess I work on (won't show you what the floor or shelves look like... ):



Comments welcome And special thanks to Mark who donated parts

Paul

[Lonestar]

Some key learnings - I will keep updating that post as I go:

- AE Stealth Gear is a direct fit on the traxxas diff (and much easier to find too!)
- Flanged bearings on M3 screws give a more than OK steering assembly (on the bench at least)
- Oven cleaner is a great deanodizer!

More to come

Paul

[Lonestar]

Some Key questions here (will update as I go and move to key learnings as I have the answers)

- What modern parts (traxxas or others) can replace the POS #1662 shock mounts please?

Thanks!

Paul

[mikedealer]

looks great, i like the black, but if you look at mine you can see that! looks awesome, nice work.

[jwscab]

what problems are you having with the shock mounts?

i think associated ones are close, though you might have to ream 'em out a little or thread them onto a 3mm screw.

[mikedealer]

these should work
http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXJG96&P=7

here's clamps/cups
http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXJH87&P=7

[Lonestar]

these should work
http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXJG96&P=7

here's clamps/cups
http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXJH87&P=7

Thanks a lot - good replacement references... sometimes cross referencing traxxas parts is a pain

Jwscab, regarding the stock mounts, the problem is that they only "rotate" in one axle, not in two... which means they'll bind in some conditions (basically if the arm doesn't swing exactly perpendicularly to the tower). The AE mounts I've tried, they have the right shape, but they are a much smaller diameter, basically the shock cap has too much slop around them - shame as they're cheap and easily available. I'm thinking I need some japanese brands shock mounts but I can't buy all of them either... and I sold my hotbodies cyclone 2 months ago, my yokomo is lent to a friend so I can't check them out.

Thanks for the help yall - will update soon

Paul

[Lonestar]

looks great, i like the black, but if you look at mine you can see that! looks awesome, nice work.

Yep thanks I saw yours... you started your thread pretty much when I started collecting the parts myself and beat me by a few weeks I love your car too

Paul

[jwscab]

well.....if you really need to have some flexibility there, you could use some silicone tubing. I've not really seen many cars that have a ball type bushing up at the top of the shock for offroad. There is usually enough slop that you can get 5-10 degrees of freedom there.

The new associated ones are ball type, but the original rc10 ones/yz10 ones/losi ones all look like the trx1 bushings. Most new cars have the molded shock towers, and these bushings are molded in, and not necessarily into a ball shape, eg, bandit etc.

[Lonestar]

well.....if you really need to have some flexibility there, you could use some silicone tubing. I've not really seen many cars that have a ball type bushing up at the top of the shock for offroad. There is usually enough slop that you can get 5-10 degrees of freedom there.

The new associated ones are ball type, but the original rc10 ones/yz10 ones/losi ones all look like the trx1 bushings. Most new cars have the molded shock towers, and these bushings are molded in, and not necessarily into a ball shape, eg, bandit etc.

Not a bad idea, but silicon tubing adds "friction" instead of binding... works on crawlers, but not on 100% finetuned racers. That's why AE uses ball types now I would say and so do most modern racers, if only to adjust for wheelbase changes I did look at a bunch of exploded traxxas diagrams, and yes they all have the inserts molded on the towers now

My mugen MBX6 has a great system... molded plastic inserts on the metal shock caps AND ball-type shock mounts bolted on the shock tower... the plastic insert is the wear part. Great combination, the best I've seen so far with the xray cars!

Paul

[jwscab]

yep, that sounds pretty trick. I don't thank many manufacturers are concerned with a little bit of lost motion at that point however.

[Lonestar]

Argh. I hit a brickwall today....

I tried to build the shock ... but the #1765 diaphragms I have are somewhat too wide for the alum shock bodies, it's just impossible to get them done right, I've tried pretty much every method I know, including no diaphragm at all a la AE shock, with an o-ring for sealing the body/cap assembly, but nothing seems to work consistently... the original part number is 1665, they are prolly a tad smaller.

Any idea anyone? I spent a couple of frustrating hours on this today, with no tangible result...

thanks for the help yall

Paul

[mikedealer]

what about these?
http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXJH43&P=7

[mikedealer]

or these
http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXJJ17&P=M

the part above is 1765, maybe new number? same part?

[Lonestar]

Mike,

thanks for the help -

they both are 1765's, ie a tad larger than the original 1665 I think. I fiddled with the shocks again these past 45 mns, and I came to something that is acceptable, although the shocks have considerable more rebound than I'd like for my modern racers.

- cut some fuel tubing, about 1cm for rear shocks, 8mm for fronts
- slide it on the shock shaft
- fill the shock 75%
- slide piston up till blocked by fuel tubing
- fill shock till oil level flush with shock body (or whatever you like, but it has to be consistent from shock to shock)
- insert carefully 1765 in shock cap
- screw on slowly, still piston up - this bleeds the shock by itself
- tighten with RPM tool for AE shocks

the shocks have more rebound than I'd like but at least they're the same both L and R.

Anyone tried to make emulsion shocks a la AE? After years of OR racing I think this is what works best... no diaphragm can conpensate for that big a shock shaft volume when piston is up...

Will update the "key learnings" section soon

Paul