Lessen's R&D stock car

[Lessen]

Step D-02

Final Shock Assembly

I'm sure most everybody has done this already and this isn't too out of the ordinary. I'm not going to go through the specifics of shock filling but I'll say this. Hands down the easiest shocks I've ever built. If you follow the instructions word for word they will come out perfect the first time.

Bladder over the shock body

Shock top inside of shock cap

complete shock and spring

I sat around for a while tonight trying to decide how exactly I would build these because of the cars left turn specific intentions. It really didn't make much sense to set them up just like the instructions since those assume you want a balanced car. The book setup is 50wt oil all around with 30lb springs at the front and 17.5lb springs a the rear. After a bit of consideration I will start my testing with the following...

Left Front: 20.0lb, 50wt ---- Right Front: 35.0lb, 40wt

Left Rear : 12.5lb, 50wt ---- Right Rear : 20.0lb, 40wt

 

[Racer 1966]

So do you have a chart for spring height to maintain you various pressure? Or are you just using the different rated springs and winging it on height?

 

[Lessen]

I'm just wingin' it all for starters to be honest. I only took into consideration weight transfer and general damping needs based on the setup from the book. You figure if the car is setup to turn left only then it should be able to maintain a higher corner speed than if it was setup for right turn performance as well. Assuming that I come to the conclusion that the weight transfer will more than likely be greater (also, I'll probably change the upper links such that I get a higher roll center). Since I'm running caps instead of foams I'll expect to require more mechanical grip since the contact grip isn't as high as say... foams on ozite. My only major reservation is that the entire base setup might stil be too firm, at least on the outside because I won't have as much contact grip to aid in loading up the right side. I consider this because the book setup is based on a foam tire setup. At any rate, it's all just a big guess Randy. I might actually like the 35 lb right front even if it is slightly too firm because I don't much care for a car that is over responsive at the wheel.. at least not when turning left only. I have absolutely no idea what to expect right out of the gate, that's why I have 12 different pair of springs, 4 different pair of tires and a full set of sways for both ends If you got any tips I'm more than willing to take it all into consideration.

 

[Racer 1966]

I can't say I have any tips for you. I was curious about the spring rates since I do happen to know a litlle about how they are rated. R&D = lots of work :hehe

 

[Lessen]

Oh ok. Yeah that's pretty simple I believe. For instance, a 12.5lb spring takes 12.5 pounds of force to compress one inch. The spring is 0.75" inch long uncompressed and 0.30" inch long completely compressed. Therefor the spring has a total travel of 0.45".

12.5 x 0.45 = 5.625 pounds of force to completely compress this spring.

 

[Lessen]

Step E-01

Servo Assembly

I going through some trial and error in this step due to my choice of steering servo.

So first I put together the servo mount as instructed by the manual. Obviously there are two of them but they can be reversed depending on the make of servo to be mounted. According to the manual I should be setting the mounts up in the "wide" position and be using 1 spacer. So that's what I did.

Here you can see I nearly have a clearance issue with my servo wire because this is a low profile servo.

So I got that all put together (per the manual, do NOT completely tighten the 4 mount screws until the entire assembly is fixed to the chassis) and the mount holes at the bottom did not line up with the holes on the chassis. Obviously I'm going to need to swap the left and right mounts around so that I'm using the "narrow" setup. Here you can see a slight difference in the shape when in the "narrow" configuration.

This configuration made the clearance issue with the wire even worse because it brings the body of the mount closer to the servo case.

So I got that worked out and I put the assembly onto the chassis. This time all the mount holes line up. So I got to thinking about that spacer... the manual said something about keeping the servo from making contact with the front bulkhead. So I thought... Well hell, I got all the room in the world since I'm using a low profile servo. I can just get rid of the spacer all together and not pinch that wire....

....So I took everything apart and removed the spacers, then put everything back together again. Just for the heck of it I decided to lay the top deck in place just to see how it looked. Uh oh.. There's another reason for those spacers. As you can see the servo arm does not center for/aft in the hole provided in the top deck. After a quick measurement it also looks like I probably need to use two spacers with this servo. Unfortunately, that means I'll have to modify that servo mount for the wire to clear. Otherwise it will end up bending the rubber grommet in excess and probably damage it or at the least pull it out. At least I know that I need to use the "narrow" setup or I would be modifying the wrong piece.

 

[Lessen]

Step E-01 continued

So I managed to do the servo mount mod and it turned out very nicely. As you can see I'm using two shims to get the alignment with the top deck proper and I've cut some material from the mount so that it does not interfere nearly as much with the servo wire. I'm very happy with this.

Step E-02

Servo Installation

 

[Lessen]

Step E-03 & E-04

Steering Assembly

OK. Been a week almost since I've done anything with this. Let's get back to it shall we. Here we essentially have the steering/servo saver assembly. First up is a shot of the parts involved.

Here we have the ball studs and aluminum bushings installed into the steering rack. The rack is black anno'd aluminum, just FYI.

Steering bellcranks installed over the bushings. Just a couple smalls screws and a tad bit of loctite. In order to keep the steering as smooth as possible I did not actually tighten the screws into the steering rack. They are screwed in completely but not actually torqued down. This will ensure the freeist possible movement. The loctite will keep the un-torqued screws from backing out.

There are two small bearings installed into the servo saver tube. This is the top one, it sits well into the tube.

Here the saver tube is installed into the proper steering bellcrank. Also noticed the bearings installed into the opposite bellcrank.

Now we have the saver spring and steering arm as it will be installed over the tube.

Here's a shot of the completed steering assembly. You can see I've installed the servo saver nut over the spring. Ready for installation onto the top deck.

Top Deck Assembly

You may notice here that there are actually two possible options for mounting the steering setup. I don't believe this is a tuning option but rather a choice made solely on the make of servo being used as the manufacturer specs will vary the geometry of the linkage. I temporarily installed the top deck in order to be sure I was using the proper holes. Obviously the forward-most holes are the proper mounting location for my particular servo.

Steering assembly over top deck.

Before you fasten the steering assembly down you will need to servo linkage. You won't be able to install it with the steering assembly fastened to the top deck. Because I know my servo arm is not 100% centered on the chassis I decided to do a little measuring before I finalized the linkage assembly. The manual states an overall length of 23.32mm but after another temporary setup of the top deck over the chassis I ended up with a length of about 24.5mm.

Time for installation onto the chassis.

 

[savagefan04]

how on earth did i miss this thread??
Josh this is a great build thread. probably the best i've ever read.
Well done

 

[Lessen]

Step E-05

Top Deck Installation



First off I had a difficult time trying to get the steering linkage hooked up to the servo arm so I decided to take the ball stud off the arm and pop it on the linkage first. Then simply screw the ball stud back on the arm. Much easier.

Loosely install the braces to the top deck.

Pretty simple here. Once screw at each corner at the bulkheads. Per the manual, I did not completely tighten the eight screws the mount the chassis supports to the top deck and main chassis. Once the battery tray is mounted to the supports I can go ahead and tighten those eight screws down permanently.

 

[Lessen]

Step F

We're pretty much at the homestretch of this build. I'll start this post with the bumper assembly. There are three main parts. The lower bumper, bumper itself and top assembly.

First I'll place the lower mount to the chassis and fasten with two screws.

There is one more screw but it is fastened via a nut above the lower plate instead of simply into the part itself.

The top section of the bumper assembly also consists of the forward body mounts. This is pretty straightforward as well. One screw per.

Slide the bumper over the posts.

Fasten the top section with three screws. Eazy peazy.

Now I'll afix the battery tray.

Now that the tray is fastened to the chassis (actually it's screwed to the four chassis supports) I can go back and remove, loctite and torque down the 8 flat head screws where the supports mount to the main chassis and top deck. I make sure to torque them in a cross-like sequence in an effort not to tweak the chassis.

I thought this was kind of cool. The antenna mount has a set screw that holds the antenna tube firmly in place.

Next up will be electronics. Unfortunately, with a little bit of test fitting I can already see I have MAJOR fit issues with the motor. This is a HUGE setback for this build. Pics to come...

 

[NCNitro]

Outstanding build thread Josh!

 

[Lessen]

So here's my problem...

In this picture you can see where the motor tabs actually pass through the bulkhead plane. In the picture the front of the motor (not seen) is flush against the opposite bulkhead. The problem with this orientation is that there is absolutely no room for movement for the motor choose a pinion and set mesh. If I turn the motor so that the tabs face upward the tabs get in the way of the bulkhead. Ideally the tabs need to face up so I can have some choice of pinion. Unfortunatly, in order to do so the front of the motor is about 3mm (the width of the overlap as shown in the picture) away from the bulkhead. I wish I could turn the tabs around so they pointed away from the motor instead of toward it, that would solve the problem. I think the obvious thing to do here is to design and manufacture a motor spacer so I can get the tabs cleared of the bulkhead.

 

[Lessen]

Motor issue cont...

So I got to thinking this morning so I decided to pull out the owners manual for this motor. To my delight, there is an exploded view of all of the major parts. From the picture it looked like I MAY be able to flip around the tabs and point them the opposite direction. So I grabbed a couple screwdrivers and went to it.

Three screws and the bearing cap comes off.

The three main screws at the other end allows complete disassembly

So here's the meat and potatoes. Those three tabs are secured to the yellow portion of the motor solely by the soldered area where the connect to the wiring. So theorectically, I apply some heat and remove the tabs, flip the left and right tabs and turn over the center. Resolder the connections and reassemble. My only reservation is that I'm not confident enough in my soldering iron to get the connection hot enough quickly enough without doing damage to the yellow mount. I need a new tip on my iron really and it's a fair 25w. It gets the job done but If I can't get those to pop in under 2 seconds I'll wait until I can pick up a 50 or 60 watt gun. I've been around this hobby long enough anyways. It's about time I have a better soldering station. I'm going to email Novak and find out if this will void my warranty.

 

[Racer 1966]

Gor for it! You probably already voided the warranty by disassembling it.

 

[Lessen]

I don't think so. These ballistic motors are made to be changed. I can purchase a different wind stator instead of a completely new motor and install it using the hardware I already have. Since it's made to be opened by the user it should still be covered I would imagine.

 

[Lessen]

So I got my small package from AMain today. It was just a few of those placement pins, a couple bearings to replace the one I messed up and these....

You may remember my complaint about how much for/aft play there was in the lower suspension arms along the hinge pins. One of these shims at each corner worked perfectly.

Oh yeah, good news.. I got a response from Novak today. Flipping the tabs won't void my warranty so long as I don't do it in a manner that would damage the motor (overheating). I'll probably do that tomorrow.

 

[Racer 1966]

Sweet, so we'll have complete build this weekend except for painted body?

 

[Lessen]

Possibly. My only hang-up that I havn't yet figured out yet is the wiring of all the cooling fans. I wanted to hardwire them but I cannot figure out how to get the fans disconnected from the motor/shroud so I can access the solder points.

 

[Racer 1966]

A big hammer does a lot