Optima for Vonats 2015

[klavy69]

Nice!

Good idea on the red piece. Got one myself with a javelin lot awhile ago and didn't realize it at the time. Came with a bunch of other kyosho and tamiya stuff so just threw it into the pile of the unknown. With this last batch you should have some good bases to start with now.

Todd

[keithrc]

Nice projects there mate, nice score on the gold one. I picked up a decent looking TO a while ago to add to my Optima collection.

A good alternative to the red front brace would be an alloy Pargu brace. Looking forward to seeing more progress.


Keith

[notarex]

Have a pargu brace coming too! Waiting for bearings to arrive to start the build, more progress soon. I did learn that the orings I bought for my desc210 gear diff are the same as the gold shock red orings, so I'm fitting those.

[rccars4sal]

The hot trick front brace is nice because its designed to give a little in hard impact.

[keithrc]

I don't think there's a need for any give really, the stock front bar should have enough give by itself. The whole front "crumple zone" of the chain drive Optima's I don't think is really necessary, how many other RC cars have them?


Keith

[Kyoshojoe]

When there is no give the gear box goes and possibly bent rails.

[keithrc]

I can see your point, but I think they could've come up with a better design than something that bends and eventually breaks, maybe a beefier front bar or a collapsible system that doesn't break and clips back into position? (I'm thinking of a version of the Schumacker Cat that had front suspension arms that did this).


Keith

[rccars4sal]

Well, despite what might be better on other cars, the hot trick brace is still a good upgrade for optima because it allows some give rather than forcing the front gearbox back, and or bending the rails.

[notarex]

When I installed a gold chassis kit on my old optima, I immediately ran it into a wall and banged in the noseplate. So I would say there's got to be a better way of doing it, -or- don't run into walls

[notarex]

I got tired of waiting for my Fast Eddy bearings, so I decided to clean the ones I had.

-Pry out the retaining rings with a dental pick
-Remove the shield
-Throw them in my handy dandy bearing cleaner with some acetone






I had the day off so I made some progress...

[DennisM]

Regarding the bumper thing.

This is one is made from Kydex and the plan is to put a piece of neoprene rubber in the gap, and fixate it with a protruding 4mm screw and nut.

Hopefully this will save the tranny guard - I don´t use the shown alloy brace on my runners. Here, it´s either stock, 3D printed or homemade nylon.

[Coelacanth]

When there is no give the gear box goes and possibly bent rails.

Actually, the part that always fails first, after the bumper brace bends/breaks, is the front skidplate. Almost every used, bashed Optima you see has this part bent or folded right up at the front. You rarely see bent frame rails and I don't recall ever seeing a damaged front gearbox with all the used Optimas and parts cars I've come across. The problem with the skidplate being the part that gets damaged all the time is it's bloody near impossible to find one that's NOT bent, and if you do, you'll have to give up your left nut to buy it.

I like the idea of having a crumple zone, but it's not engineered properly as such with the Optima. The bumper brace breaks way too easily, causing the skidplate to fold up. I like the idea of the Pargu alloy brace preventing this from happening. I think of the bumper brace being somewhat analogous to the RC10's nose tubes.

Dennis, I think you're onto something; I actually think the original design idea, bolting the bumper directly to the skidplate with that big nut & bolt, actually contributes to damaging the skidplate. I designed a custom bumper for Barney that's quite similar to your design. The hope is that the bumper's angle will help it to "skip" up off an obstacle, and not directly damage the skidplate as it's not bolted to the front of it. The alloy bumper brace is there just in case, but it's now a separate structural component instead of being combined with the bumper.

EDIT: I've seen some people simply cut off the bent section of the skidplate and build "runner" Optimas that simply don't use the bumper brace at all; as long as you can do without a front stabilizer and fabricate a custom bumper like these.

[keithrc]

On more than one occasion I've seen the lower guard bent right back and the front brace broken completely in half on both sides where the holes are (and cringed I might add ), the holes were obviously there to allow the brace to bend or break in a heavy impact, good for Kyosho back in the day meaning they'd sell lots of replacement front braces and lower guards. Even though they made thicker lower guards for the Turbo Optima's and Salutes it did'nt fix the problem. Stating the obvious there but anyway...

I can't say I've seen damaged gearbox housings from frontal impacts but I have had bent chassis rails, usually at the offset holes where the steering bell-cranks mount up, the holes are near the edge of the rails so they have a weakness there.

As you said Coelacanth a crumple zone is good but in this case not a good design. Maybe a relief section to allow for an impact while avoiding any damage? By "relief section" I'm thinking as you mentioned, cut away the section of the lower guard that's prone to bending and using some thick foam rubber (as some on road cars use for a front bumper) between the bumper and gearbox and cut away the top section so it can be attached to the front brace to allow for fitting of a sway bar.

I also had elaborate ideas for a front brace that has some give built into it but that would only allow for damage to sway bars.


Keith

[notarex]

I made a bit more progress last night. Swapped the Hitec 645MG out of my Sawback and into the Optima- I love Hitec stuff, it's been inexpensive, reliable, a little slow but strong. I scored a Graupner HV servo on Amazon that went in the Sawback- $15 bucks, great specs. Sometimes I've found deals on Amazon like this, as soon as I bought it- it went up to $50 .







The linkage is a little different than stock, but functions great so far.

I got these in the mail yesterday, they will go on the outer linkages



I talked to Ed at Fast Eddy, he was nice enough to send along the two 14x8x4 that are missing from his Optima kit- maybe he will add them in the future? I am pleased with the quality of these bearings.



Some seriously beat up wheels were included in the latest load, I normally wouldn't paint wheels but these needed serious help. I chucked them up in a drill:



I had to take off the entire ridge on the outside of the lip because of the damage:



I painted them gold, came out alright I think. This is where I'm at now- waiting on a HW ESC, spectrum receiver and some double dees. It's got the 34 deg stock motor in it and the chain drive is set up to underdrive the front. I used the Hot Racing final pinion seen here:

http://www.ebay.com/itm/Hot-Racing-19t-Steel-32p-Pinion-Gear-5mm-Bore-NSG3219-/381158222039?

It seems like it will work fine, but there is a rough/high spot in the diff gear that will have to wear in. Certainly better than the trash that Kyosho provides.

I love the look with the nerfs:



That's all for now, just need to put a lid on it and do the wiring.

[notarex]

Some goodies for the new build, Thorp underdrive and final pinion + carbon fiber sheet:



I used these shiny outdrives from a duratrax something:



The Hobbywing 1060BR, this thing is cool! Waterproof, little jumpers to set the modes and a built in tab hanger for the on/off switch. It's little details like this that make me a Hobbywing believer.



Proper clay tires now. Optima #2 starting to take shape in the background...