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My "Super Fly" Hornet Build Thread

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I have been building what started as a Hornet front end mod. I started this about a year ago and figured for those that didn't see this in my showroom, I may as well go over it from the start. Well, it didn't stop at the front end, for better, worse or expensive. I started on a design that would not hack up the front end and be a complete bolt on. For the most part, that is the case though some holes will need to be drilled. We will get there later. I welcome advice and criticisms but should you criticize something, I most certainly expect a better idea coming from you. I feel I have though of everything but sometimes a fresh set of eyes can show something that I missed or just plain didn't think of.

Here is how this mess started. I have a few race cars. I have to say though, my favorite is my racing Hornet (no disrespect to be beloved RC10 B2 and my RC10, both of which I drove as a factory team driver). After a couple weeks of tearing it up on the track, I wanted to upgrade a few things.

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When I tore the car down one night for a bath I saw that the shock towers were breaking! Stress cracks all over the chassis. I then decided to run a structural simulation. This showed the area of contention. I do have the lower brace reinforcement included in the simulation but as a way to save computation cycles, it is represented by a simple beam load.

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On my car, these were the areas my chassis was cracking. I then created a simple brace that you epoxied to the inside of the chassis in those areas that would then spread the load over more of the chassis. It was a great fix but one I would come to reinforce later on while working on project Super Fly. These, in red, are the glued pieces of styrene.

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Well I then moved on to the front end. It started with this car as inspiration when I finished the resto:

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I took a set of Cyclone arms and copied the datums. This is not a simple design mind you; the geometry is very unique as the arms on the chassis are not installed conventionally like a modern buggy (parallel to the central axis of the chassis) but at a slight angle. This requires that the spindle be at an angle to counter act the mounting position. From there I had to make the arm look like something that Tamiya would have created. This means it could not be boxy and weird like the Cyclone arms and not be full of trajectory ribs like the CRP units (nothing against them, they are great but they are clearly not a Tamiya affair). Mine are clean and simple; everything has a purpose and due to some simulation testing, there is no excess material.

The main issue I had was the shocks. The Cyclone has a very unique unit for its a-arms. They are rare, weak and hard to repair (I have 6 sets, I should know). The thing is, they are pretty and do not change the look of the car like the CRP front end does. You can always chop off the shock towers and replace them with the metal ones on ebay but again, you are changing the look of the Hornet by adding these massive and tall shocks up front. I'm not saying its a bad thing to do, I just don't like it. What I have done is create and arm that will capture the shock base through the arm itself. this allowed me to gain 10mm of shock size. Couple that with the ability to add the shock mount on the top of tower and now we can mount a conventional shock.

Which leads me to my next problem. The shock that I wanted to add was off of a Losi 1/24 short course truck. Problem was the shocks, springs and unique parts required would have been in the range of $70. Plus they were tiny and though adorable, they were too weak. I found some 50mm shocks for a m-class 1/10 scale car. Those a cheap, plentiful and easy to work on. The space (eye to eye) that I had to work with on the cars arms was 49mm. Talk about right on. The have 10mm of travel which I'm not happy with for large jumps but its ability to negotiate terrain is almost 'un-hornet like', as in it actually can! I added springs from a 1/16 rally car as the on road units were far to stiff.

The next issue was that the upright for the cyclone is too close to the mounting point of the shock and the upper link was in the way (in fact, it rubs the spring on the stock Cyclone). This meant that I had to move the shock more inboard (and therefore more vertical) which was good and then move the ball end mount for the upright from the top to the front. This makes the shock fit like a cat in a shoebox: Just right.

Lastly, how do I mount the upper links to the chassis? Well I could have done what panda did and use the Hopper body mounts or I could do it right. I made an adapter that brought the ball ends more in line with the upright and also took the load stresses off of the stand off (the body mount) so that now the stress from both sides is concentrated in the adapter (same principle with a brace between the shock towers).

I didn't want weird, rare or costly hardware holding this together. This was a Tamiya so Tamiya bits were used everywhere so that it looked like Tamiya made the upgrades. The screw pins are 25mm units from a WW2 (though a zillion Tamiya's have them) and you can use a 3mm hinge pin if you choose. The ball ends, well, 5mm Tamiya units.

I also added aluminum servo mounts, a killer steering linkage I got on ebay and a Kimbrough servo saver. I also have reinforced knuckles coming in.

Colors were chosen to be bright and loud. I wanted to make everything jump out and visually punch you in the face to shout 'look at me! I't upgraded'. Shapeways allows you to pick a lot of colors when you print the parts. Black would have blended right in there and looked completely stock.

This is stage 1 or Project 'Make the Hornet as good as it can be and ignore the fact that entry level toy rc cars are probably better and cheaper than the time and money you are putting into this car'. From here, oh boy, do I have so good stuff. These ABS parts are insanely strong. I cannot get over how light they are while taking all manner of abuse.

Yes, I know I could 'just get a Hotshot, its a better car' but that's not the point. The Hornet is my favorite Tamiya ever.

Here are some images of the progress.

All the bits I made minus the shocks of course.

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Here is all the required hardware. All cheap and easy to get.

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Installed:

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Note the horizontal cross member brace.

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This brace helps better align the upper link.

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Very nice

You going to be selling this as a kit? If you make enough money you could design a 4 bar linkage for the back..............................

I have so much admiration for people who have the skills you have, I would love to able to use my computer to do more that Facebook

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Thanks guys. Nobbi1977 - right now I want to make sure the parts work correctly and are durable before I think about selling them. I dont want anyone to get junk. This 3D modeling is not that hard. there are a few members on here that have been making simple to complex parts, many with free software. If you know how to use a computer, you probably can make your own custom parts.

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Update 2=

One of my engineers asked me how much time I have spent on my Hornet design. I thought that it was a good question so I decided to add it up. So I work on this at lunch sometimes but more often than not I use this model for demonstration purposes like if someone wants to see how gears mesh....or mechanism connections....or working with large groups of engineers....I think you get the idea. Well, what happened is that now this is the only model I use. I sat down and using our consulting rates discovered that if someone had asked me to build this model to this point (trust me I’m not even done with it yet) from the measuring of the original parts to the build and layouts and all of the custom parts, that this would have cost...are you ready for this? Well, sit down...$23,390. Yes, for a Hornet.

I have many of these parts done and I am amazed to see how strong they are! I have been beating up my test mule and nothing has broken anywhere.

You may be wondering what you see so I will explain:

1. I had to make the rear shocks fit in the stock base ball pivot location so I made a ball end that fit the shock shaft and the base collar. This makes the shock work properly.

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2. Unfortunately, since the shock was larger, when you accelerate, the motor would hit the shock body. I then had to redesign the shock mounts so that they were 5mm further back and inboard by 2 mm (they will hit the shell otherwise). This changed the geometry for the best I discovered. Later, you will see that I installed the original shocks due to the fact that I could not find soft enough springs for the car. These, though the softest I could find were still way too hard.

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3. That led me to the garbage body mounts that the hornet has in the rear. I made them larger and stronger with a nice base that will fit the body nicely. Unfortunately, I ended up scrapping the idea to run the body at all so now I use them as a transponder mount.

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4. Speaking of garbage, the rear wing mounts are as structurally sound as a stack of cats. I then decided to remove the wing mounts on the body, have these posts stick up and have separate body pins. Fine, you will need to remove 5 pins to remove the lid BUT this also means it won’t ruin the shell and you can easily replace the wing. This worked well but it is intended for a aftermarket wing.

5. Tail lights. I wanted them.

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6. Rims. I love the stock wheels on a hornet. At the track I go to, the surface is clay and they stick as well as ball thrown at a wall. I also utterly despise low profile tires on this buggy. The solution is a low pro wheel that has its edge painted black to look like it’s a standard wheel. Plus it looks like a meaner version of the Hornet wheel complete with faux screws. It even fits the stock wheel hub.

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7. No structural rigidity. The Hornet was an afterthought. It was never designed to have a lexan shell. Removing the hopper lid ruined the structural integrity of the chassis. So I made a complete roll cage that will not only tuck inside of the stock shell but according to my structural analysis, it will make the chassis 35% stiffer. I was hoping for more but we are talking about a 3d printed part. It uses all the stock mounting locations so no holes are ever drilled although you might need a long screwdriver to reach some of them.

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8. 3rd Shock. The 3rd shock mod on the hornet is hit by the trans upon full compression. Not cool. Therefore, I used the cage as a mount for the 3rd shock. This also allows the speed control plenty of room to reside under the shock. More importantly, it looks awesome and requires a simple 60mm shock.

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I have tried to improve the performance and looks of the car without changing the cars heart and soul. I could have made an independent rear end but then its not a Hornet. I could have chopped the shock towers off the front but to me, its not a Hornet any more. Is it better? Yes. Hornets are not supposed to be good. They are fun. That's what makes them great!

I hope you enjoyed this as much as I have! This isn’t all done but I couldn’t wait to share it! You will find that I later deviate from my plan to not modify the chassis, but I both had to and the result it totally ridiculous if I do say so myself.

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Wow! I figured after 30 years, there wasn't much development potential left for this chassis. Clearly I was wrong. Nice work!

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This thread is awesome. The Hornet was my first rc and still my favorite. The work you are doing is amazing. I hope you one day make the parts available as I'd love to enjoy the fruits of your labor.

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I have a thing for Lunchboxes and the WW2. I know your dilemma. To improve the vehicle while keeping its character. Awesome work so far

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Thanks folks. This has been both a lot of fun and frustrating at times. I will post more!

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Is the plan to offer the suspension arms for purchase? I agree with you fully, the shocktower is alot of the hornet's looks, and changing it too much takes some of it's character away.

Outstanding work btw.

I have a new built Hornet and a Gh I was contemplating what to do with. Even my son thinks the bump steer is too much. "It does not go where I want it daddy".

I know what options are avaliable as far as hornet suspension mods go, it was more a question of which route to choose. That was until I saw this post.

The Hornet is my fav too. I actually had the scorcher as a kid, later the fox, but always wanted the hornet.

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Ok Update 3:

I was having trouble designing the body as these types of free-form designs are not things I am used to. I finally got through it and everything is off to Shapeways!

First off, this car has taken hundreds of hours to design. Let it be clear that I do not have, nor have access to a 3D scanner. Therefore, every part of the hornet that you see here was measured by hand, piece by injection molded piece. That was not fun. Second, you are looking at a husky Hornet. This little guy, according to my simulation tools, is now 20% heavier without the battery. Is this bad? Heck no, the problems with the Hornet first stem from the fact that the car is too light. Now that the car is meatier, coupled to the fact that I am still going to add weight to the car to set the CG where I want it, it will not be able to absorb little lumps and bumps much better. Now I am also using LiPo batteries which reduces weight to dangerously levels.

I am excited about the 3rd shock mod as there is no way that, under compression, it possible to jam a shock of any kind in there without it being hit by the trans. I know this because I have copied every single one I have seen. Many are so close to being perfect and fitting bit even 1mm of interference is not cool with me. One member added a 3rd shock to his Grasshopper 2 via cantilever, inboard. I saw that and knew that was the solution. I added mine and incorporated it into the roll cage.

My take on the 3rd shock with the body installed:
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Oh, speaking of the roll cage, the cage will increase the rigidity of the chassis by 70% in the areas of contention: the front end and front suspension. The cage wraps around all of the electronics and mounts to every single mounting point that the chassis has, including the Grasshopper body mounts, MSC mounts, nerf bar mounts, and even the antenna mount (it will be relocated). The main cage is 6mm in diameter with some 4mm supports in areas deemed to be ancillary. The cage also has the body that attaches to it. On the front, the body is clipped on for easy removal. On the sides, it is screwed on as those will rarely need to come off. They are screwed in from the outside as the cage needs a lot of screws to be installed so I did not want to remove the cage every time I needed to work on the car. The roof too is screwed in. I took some artistic freedom with the body as I wanted it to still look like a Hornet but also look like this one was not messing around. The head lamps are actually attached to the front of the frame and not the body as a support that goes from tower to tower will be in the way of removing the shell should the lamps be installed on the nose.

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The rims, as I mentioned in the last post, are custom for this car. They increase wheel track, look like original ones and mount to the stock locations. On top of that, they accept modern low-profile buggy tires. The outer lip of the rim is painted black to get the effect of a smaller diameter rim.

Oh here is a close up of the adapter I made for the after market 80mm unit that I installed. However, the correct mod is something more like the Super Hornet rear end. This is what JunFac created a couple of years ago. I think I need to look at that mod for better rear geometry:
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Here is a closeup of the 50mm shocks installed with the dual link front end I made. The upper link isn't shown because the way that Pro/ENGINEER works, that linkage is used in the mechanical simulation tool and not a modeled part.

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The rest of the parts are the same as before save for the part that I wanted to make since the start of the project: A battery door that won’t fall off even by looking at it. It actually isn’t much of a door, just a thin piece of styrene but with a mount added between the chassis and the transmission. This will allow the battery tray to be installed with clips, in the same fashion of the Super Hornet, and never fall off! I can’t wait to get the parts!

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The images uploaded are screen shots. I did not have a chance to render these as the computer I am using is lacking in the horse power area. Anything you see in RED as been modified by me, including the rear shock ball ends. They fit the stock location without making any changes. As of this point, everything you see has been printed and assembled. I will take some pictures and let you know what I think. Here is a hint, I am kind of disappointed in a couple of areas.

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I've posted about this idea before, and either I'm totally wrong or I've not explained it correctly.

The 3rd shock. Why does it need to be a coil over? All it does is damp axle rotation. Seems to me that a straight oil shock would work for that purpose.

This came from my own Lunchbox 3rd shock mod, seeing how the gearbox hits the coilover at max compression. I liked your solution of the inboard cantilever setup

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Nice thread, I saw some of your prototype pictures before on the showrooms if I remember right.

Have you had a chance to take a look at the DT-01 rear suspension yet? I think you might find it very inspiring for you Super Fly Hornet development.

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Nice thread, I saw some of your prototype pictures before on the showrooms if I remember right.

Have you had a chance to take a look at the DT-01 rear suspension yet? I think you might find it very inspiring for you Super Fly Hornet development.

There is a square hole in the hornet chassis at the back of the battery box waiting to be filled with a pin for the dt-01 back end. I just need to get off my *** and learn this kind of thing.

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I've posted about this idea before, and either I'm totally wrong or I've not explained it correctly.

The 3rd shock. Why does it need to be a coil over? All it does is damp axle rotation. Seems to me that a straight oil shock would work for that purpose.

This came from my own Lunchbox 3rd shock mod, seeing how the gearbox hits the coilover at max compression. I liked your solution of the inboard cantilever setup

You make a good point. I had thought of that with a thick oil filled shock but the problem, for me anyway, is that the trans will ultimately fully tuck itself under full load and more importantly, whilst in the air. I have noticed that the 3rd coil over shock now acts as part of the suspension upon a landing. Oh, and it looks cool. HAHAHA! :rolleyes:

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Nice thread, I saw some of your prototype pictures before on the showrooms if I remember right.

Have you had a chance to take a look at the DT-01 rear suspension yet? I think you might find it very inspiring for you Super Fly Hornet development.

There is a square hole in the hornet chassis at the back of the battery box waiting to be filled with a pin for the dt-01 back end. I just need to get off my *** and learn this kind of thing.

Hmmm, I have not. Is that the kind of ball pivot rear end? I was ATTEMPTING to keep the bulk of the stock parts but I have to say, that is not an easy task. We will see what you all think of my V2 front end.

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The DT-01: It's not a ball pivot end, but similar. There's a peg attached to the chassis, which has a tapered hole. This hole is protruded by the metal shaft of the rear pod. This enables full articulation and thus makes both the third shock mod and the springs in the slots unnecessary.

The rear dampers themselves are angled more horizontally, with very light springs. Very light damper oil is needed if using CVA oil dampers. All in all, in my impression this type of suspension works better than any other mod, while still keeping a bit of the Grasshopper's lineage character since it is still a solid rolling

rear axle suspension.

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Really looking forward to seeing the parts when they arrive. How long to wait now would you say?

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Really looking forward to seeing the parts when they arrive. How long to wait now would you say?

They might be at the office but right now I am sadly out of town so I cannot wait to get them!

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The DT-01: It's not a ball pivot end, but similar. There's a peg attached to the chassis, which has a tapered hole. This hole is protruded by the metal shaft of the rear pod. This enables full articulation and thus makes both the third shock mod and the springs in the slots unnecessary.

The rear dampers themselves are angled more horizontally, with very light springs. Very light damper oil is needed if using CVA oil dampers. All in all, in my impression this type of suspension works better than any other mod, while still keeping a bit of the Grasshopper's lineage character since it is still a solid rolling

rear axle suspension.

Ok I took some pictures of the Rockbuster rear end. It has this weird little bracket that fits in the slot at the back of Grasshopper/Hornet chassis'.

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The tab on the rear of the grasshopper gearcase is required for this mod to work. What is odd though, is that the screw that retains the trans has a spring on it. It appears that this mod is a 3D shock but know that it does not work that way. The trans is in there with just enough force that the trans is only able to articulate side to side but not translate like they are designed to. Even this simple DT-01-esque mod is a huge improvement over the original.

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So I think these photos are over due. No one has seen these before so I am excited to post them. This is V1 of "Super Fly".


Completed Car.

The slots on the hood are an homage to the original hornet:

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Top.

Version 2 will have the roof 6mm wider as I think it looks better.

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Removable hood.

The front mount is stock where as the 2 pins at the rear of the hood are part of the roll cage. I had to do this or there was not going to be any way to access innards without completely removing the cage.

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Frame installation.

Boy did I add a lot of screws. This is a complete pain to install but the increase in rigidity is amazing.

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The frame even screws into the mechancial speed control mounting area, that is if I had not chopped it off when this was my race car. Out came some Kydex and a drill.

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The body either screws on (roof and sides) or is held on with body pins (the hood):

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Painted 3D printed plastic is rather simple as it really absorbs paint. That said, PRIMER! USE PRIMER! A few coats and some sanding later it looked good. No mirror finish here but we are talking about a prototype test mule.

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Head lamps are mounted to the front of the cage so they are now independent of the body.

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Servo is nestled in there rather snugly.

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3rd Shock Mod:

Everything for this mod was designed by me. As I mentioned in the past, this was not my idea. Another member (taz-nz) on Tamiyaclub made this mod on his Grasshopper to, ablight without the cage. It is WAY overkill but not only does it stifle the torquing of the trans, but it now acts as its own suspension. The front is mounted to the cage with a standard Tamiya MD1 spring mount. At the rear, a ball cup shock base mounts to a cantilever arm with a 200% geometry decrease to the shock. this means that the trans can slide 15mm up and down in its slots while the shock only compresses a total of 7.5mm. This allows for a shorter shock. Even the metal mount is 3D printed in stainless steel using a process called laser sintering. Man I love shapeways. From the cantilever arm, it joins a ball end to a threaded rod which attaches to a Tamiya A13 spring base (used at the bottom of the Grasshopper/Hornet front end). Of course a notch in the trans case is needed to allow the A13 part to have the trans shaft slid through it.

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Rear shock bracing and frame integration:

The rear of the frame mates to the custom rear shock mounts I made earlier in this thread, They alse screw into the resistor mount and I made sure that it would still clear the JunFac chassis brace. Here you can also see the wing install. Currently it uses 2 body mounts to hold it on. Later, it will be drilled to accept the same kind of Piano wire mounting that most competition buggies have. This is both faster to install/remove as well as having a very high tolerance for roll overs and crashes as the wire bears the brunt of the roll.

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Rear Cage and body:

Here is the rear of the left body panel. I tried to make it flow into rear chassis as much as I could. The frame is mounted to both the rear Grasshopper body mounts as well as the rear upper nerf bar mounts. The screw passes through the frame and still threads into the nerf bar.

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Rear Suspension:

In terms of looks, you cant beat it. However, when functionality comes into play, the springs are way too stiff. I was hoping to locate weaker one but alas, I could not. I even looked at having some made but it was cost prohibitive. Still, we the reduction in weight thanks to the Lipo's I run, the stock ones will be fine until I find better units. Plus, the geometry is only slightly better. I need to rethink this rear end still as I am simply not content.

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Rear lights:

Useful? No. Awesome? Yes. These come off with 2 screws when I race though I think they are incredibly tough.


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Rims:

These were modeled to fit the stock location, increase width of the car and accept the best tired I could find for the track surface I run on. I am not happy wit the size as they are just to big in my opinion but at least I was able to keep the look of the originals down to the faux screws. The edges are painted black to give the look of an old school high sidewall tire. They would look better with a matte black but the gloss cleans way better at the track.


Front:

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Rear: Note the chip? This is what happens when you roll the car at the end of a straight and some jerk does not heed your warning to "GO LOW" and plows into the car with a 1/8 scale something or other on 4S. Tell me these 3D printed parts aren't strong! This was all the damage the car got.

15929937961_d8914878da_b.jpg


I still need to install the battery retainer as well as my V2 front end. That hasn't arrived from shapeways but when it does, you might doubt that this is a Hornet any longer.
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