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Nice build Paul! What is the carbon-patterned thing behind the bumper? A piece of lexan to cover the half pound of lead you had to add?

Spoiler alert, heretic is in da house !

Next part of the story is shocks, then real-world handling (and mucho lead at the front indeed !)

Let's talk shock absorbers now... not many photos from then on as I was in a rush to finish the car before raceday

My belief is, when you get the suspension freed up properly and not too goofy angles, and your diff/slipper comber is, then all it takes getting ok is the shocks to get a 2wd at 95% of its potential

So shocks were next...

As usual with most non-racer-cars, the shock bodies were full of crud, the oil was all murky, full disassembly totally mandatory, and lots of time, paper tissues and brake cleaner to clean up the inside of the bodies, especially at the bottom.New green-slime drenched MIP seals all over are a must, as well as coating the spacers in green slime too ("t's a little tribological miracle" - those in the know will get it ) is a must.

For smoother shock action, you can file the thick spacer between the o-rings so it becomes about 0.1mm to 0.15mm thinner, o-rings will be squeezed a lot less and there will be less shaft friction. It looks like as years passed by, these parts got thicker. I remember reading/viewing a tip article/video with Richard "The King" Saxton mentionning this, too.

The issue with this overall OIN setup is, there aren't that many setups available around. The suspension cinematics are not that well documented, it's never been properly "developed" as a racecar, so you're alone in the dark if you want to make it perform. I figured out it'd be closer to a B4 than a Worlds Car cinematics-wise, so I pulled out an old B4 "carpet setup guide" from the UK from my archive, and I settled on #2 pistons on both ends, silver buggy springs in the back and blue truck springs in the front .
I am not sure which version of the front shocks I have, I am thinking front 10T shock length. In any case, it took a few mock up assemblies to figure out how many spacers inside the shock would be needed - remember we're talking indoor carpet racing here, so you don't want too much droop. You still want to land the jumps properly and don't want too "lively" a car on the whoops so some droop is still neeeded. I figured out 3 thin shims inside each F/R shock would cut the mustard as a starting point.

To please a painful but correct racing buddy, I cut then rounded the edges of the upper mounts to nut cut through the carpet when not on all fours:
Oil-wise, I have honestly lost track of how many front/rear combos I've tried... but frankly the best I could get to was so-so, I never was happy about static performance on the bench. Statically, when it'd feel ok when pushing the car suspension down, it'd be okayish (so oil is right-ish) but the chassis would slap the ground when dropped from 1 to 1.5ft heights, so the piston/oil/droop combo wasn't that right, never. I think I ended up with 50WT up front and 45WT at the rear, knowing it was at best very sub-optimal. I was tired of messing around and figured out I'd set it up at the track on d-day between runs, and play on the shock mount hole on the A-arm too at the track - because there is only so much you can diagnose on the workbench!

Lastly: we're looking at a rear-motor 2wd. Absolutely NO-ONE races this configuration seriously by now on carpet or high-grip surfaces: we've all finally admitted Mid-motor is superior in these conditions. On my car, the shorty is mounted inline for visual reasons (looks good!) but really the front end is stupid light compared to a MM car. Time to pull out the lead stickies. As Heretic pointed out above, there is one leftover of the old cwf-vinyl'ed body tied up to the nose tubes on the front of the shock tower. There is no lead below there, but the previous owner mounted a 7g weight on the nose itself, and already 41g behind the shock tower here:
I also added 40-ish grams of lead (sharpie'd black for stealth looks!) next to the lo-profile servo, to both add weight up front as well as "rebalance" the L/R mass (servo is on the right only now).

Net, the car already has about 90g of ballast at the front. This is not totally senseless given the low-profile (lighter) servo, the (lighter) shorty, and the stupid-light front end

Time to go racing now! First, put on an appropriate attire:

Up next is race report, namely the disastrous first couple of runs, some more work on shocks, more ballast, then racing impressions, and key learnings and next steps, like at work...

Hey Paul, nice job on the car and good luck with racing. I was never really happy with the suspension geometry of my OIN either. It has to do with the unusual combo of parts and the fact that shocks are too vertical, especially in the back. The fact you can't use the outer shock mount hole on the rear doesn't help either.
For a carpet race, I would redesign the shock towers and put the shocks more at an angle to stiffen it up and make it more progressive.
One question: why don't you reverse the mounting point of the camber ball studs on the front c-hubs. It puzzles me a lot

Asso_man! wrote: ↑Mon Dec 11, 2017 4:33 am Hey Paul, nice job on the car and good luck with racing. I was never really happy with the suspension geometry of my OIN either. It has to do with the unusual combo of parts and the fact that shocks are too vertical, especially in the back. The fact you can't use the outer shock mount hole on the rear doesn't help either.
For a carpet race, I would redesign the shock towers and put the shocks more at an angle to stiffen it up and make it more progressive.
One question: why don't you reverse the mounting point of the camber ball studs on the front c-hubs. It puzzles me a lot

Hey Master,

Thanks for the considerate comments.

There are a couple of other developments I will explain in the next posts, and I want to try a few other things the next race - but I agree with you that it's likely a lost cause as far as pure performance is concerned. The OIN is a hodge-podge of parts that were never really designed to work together, and guess what: they really don't

Funny that you were the only one noticing the front-mounted outside camber link : I had to move it there as the steering ballcup on the spindle would hit it at full throw when the front was loaded... one more parasitic effect that proves the point that it's not a holistically designed suspension. Could be linked to the SC10RS spindles (needed to mount the hexes...) this time.

I think it's also a testimony to Roger, Curtis, and Cliff's engineering skills : their original short-armed RC10 and then team/world car was truly revolutionary because the whole thing was working so well together, with almost no design idiosyncracy, nothing hitting/binding/limiting anything else. All this before CAD. Respect

(more later)

I wish the OIN idea could have been developed more with a handful of guys that could really dedicate their time to it. I'm no suspension guru, especially when it comes to off-road. But given time, I think they could work well. I built my original one and only race it one time ('08 Vonats) and I thought it worked quite well. I was also pretty happy with the OIN B1.5 I built for the '15 Vonats.

Another issue I think hampered any real development of the concept is everyone had their own vision of what OIN meant. Some guys just did the mods on the back but not the front. They ran truck towers instead of buggy towers. They used stock rear arms and B4 rear hubs. B4 castor blocks and knuckles instead standard rc10 items. Or they designed their own arms to use different rear hubs and cvd's. That's all fine, but it's does nothing to advance the idea.

What it needs, which it would probably never get, is have 6-10 guys build a car in the form of the original idea. And, keep them all very similar....... almost like a kit. Then go out and test, share info, etc. That's the only way to help it evolve.

At the end of the day, the whole reason behind the OIN concept was to run b4 wheels on an rc10 with basically bolt on parts. And, it did that. We weren't trying to reinvent the wheel.

The other thing Paul that will very much help your handling is to move to buggy shock towers. Since you are still running the truck towers, your geometry is going to be all wonky at best. the old is new is really similar to a B4 arm length and spacing, so if you can get the shock angles closer to B4, you will be that much closer. You can redrill the truck tower to make it the same as a buggy tower, it just ends up with some 'wings' hanging out. the front end will improve having the shock a little more upright as well.

Hey guys, don't get me wrong: I love the car, it looks totally bada$$, it can very likely drive ok outdoors - I think it's fantastic idea, and I'm sure it can work reasonably well vs. similar RM cars, at least at the club racing level.

when racing a bit more seriously, every bit counts - even if you stop racing development in the late noughties, so right before the MM craze that started with the ugly-as-hell X6 and the C4, every bit counts. There is no car that ran 1s faster than its predecessor, but still, a B4 would run 1s per lap faster than a worlds car for instance - that's 0.25s per RC10 generation (wait - scrap the B2 off the list, please )

What I mean is, yes, some teamwork development can certainly help, and good fingers will most often make up for the car's shortcomings themselves, but all things equal, an average setup on a B4 will be faster and easier to drive than the best-developed OIN setup! Still I respect immensely that you guys have made up such a car from shelf engineering

If someone still has a B4 handy, I would appreciate some measurements too, because you got me thinking, here:
- A-arms inner hinge spacing, F and R (was quadra-symmetric, wasn't it? So F = R , but how much between L and R?)
- A-arms length F, and R please
- Where were the mid-setup holes located on the A-arm from the inner hinges?

Joe, can you elaborate some more on the shock tower thing? Just slap on some team car towers? Or drill the truck towers to have the same mounting points as a B4? (in which case I need B4 measurements again!)

From there and with some basic trigonometry I should be able to steal some further B4 info

Thank you,
Paul

just a regular rear shock tower for any rc10 b1 will give you tons better rear shock geometry.

up front, the rpm worlds tower is a starting point, especially since you have the 1.02" shocks, but Jeff(GomachV) has probably 10 different front towers that guys have sent him to route out, to stand the front shocks more upright.

all things considered, if a person could measure out a b4's geometry, and apply it to a 'OIN' build, I'm sure the performance would be extremely similar.

Yes, comparing it to the handling of a B4-5-6, they should be better that an OIN car. I'm comparing the OIN concept more with a stock rc10. Vintage racing, really. You want it to be at least on par with a stock rc10. The goal would be to make it slightly better. Even if it's only on certain tracks.

For the newb here, what does OIN mean?

Old is New

10 years ago, there weren't many 2.2 wheel options out there for the rc10. The original OIN concept was a way to run modern wheels (B4 at the time) using bolt on parts.

'Old Is New'

back before the re-releases and renewed parts supply, the standard wheels started to get pretty hard to find, so guys were poking around for substitute parts, with the intention of using modern wheels and tires (aka B4). it also was a natural progression to investigate longer front arms to better equalize arm length and the fact that you could find beater trucks pretty cheaply.

**wow, already 10 yrs ago!**

scr8p, jwscab, understand. I'll check out what I can do

Back to raceday experiences:

This was my first race with this "hand-made" car, so I knew there were going to be challenges - my target was to not break the car and not spend the whole day scratching my head in disbelief at how poorly this thing would perform I was also hoping to get that suspension sorted out somewhat... If I ended up in the middle of the rankings, I'd be happy - making the B-main would make me super-happy, making the A would be totally unexpected (and unrealistic)

Here's a pic of the track:
Additionnally I had my 8.y.o. son with me for his first offroad race - he's raced a few onroad races before, but he's still young and unfocused, plus we never practice on a proper track, all we do together is backyard bashing so I knew this'd be epic for this reason I rebuilt his Ansmann Mad Rat, which is basically an ultima RB5 knockoff, it's tough as a brick especially with the speeds he can reach with the Mabuchi I installed in his car

(you can see him screaming at me, second from left, in his junior series )
Before the track opened at all, I went for a quick slipper setup on a piece of carpet that was exposed close to the pitlane - the V1 sweet spot is really really narrow, the difference between too much and too little slipper action is withing 1/8th of a turn

Net, about 40 racers. Time to go for controlled practice on a track that no one had ran on so far. Due to my ok performance from the previous years, I started in the fast heat... They should have known better

First impressions are so-so, namely because of poor hydraulics (what a surprise). The rear bottoms out at most landings, which unsettles the car considerably and prevents to lay down the power as soon as needed. Additionnally, the front end washes away in all the tight turns - while the car is surprisingly good in the sweeper with the (mild) whoops. Overall, I spent my whole 5mn opening the door to the top dogs This doesn't account for the fact that I was marshalled by the wing once, and you can guess what happened: the philistine marshall had never seen piano-wire-mounted wings so I had to walk down the rostrum to fix the car myself during the heat

At the end of controlled practice, based on the three consecutive best laps, the reseeding puts me in 17th spot, so that's #1 in the C. My laps times are all over the place, but my best lap is in the mid 16's while the TQ-worthy guys are in the mid 14's. The good news is, I had zero expectations

My son's controlled practice is a disaster, he bangs every possible board - the fact that his transponder decided to let go after a couple of laps actually was a relief, really

(TBC'ed)

jwscab wrote: ↑Mon Dec 11, 2017 11:26 am 'Old Is New'
[...]

**wow, already 10 yrs ago!**

yep... that's crazy when you think about it!!!