TOPIC:

Hi everyone,

A R/C club nearby is organizing a 540 cup every year, only condition to register is to have a GrassHopper châssis to run and a 540 Silver can motor. Decided to go for a Hornet...

Before I started this morning, I took a picture of the box...


For the small story, there is one thing I found surprising with this kit by comparison to the few kits I mounted recently. There is part bags A, B, C, D and I was expecting them to be ordered as per the instructions, but it is not the case. I had to open all of them. I find this really surprising, especially by comparison with the Super Storm Dragon which is using exactly the same châssis and have ordered bags...

Anyway, I started mounting the legendary rear bridge...


And attached the motor to it...


Then, the assembly join the tub, with an axle maintained in position by some springs. The interest of the spings itself is subject to caution, and generate a smile: you already understand why this buggy gives a whole new meaning to "precision" 


Few minutes later, I added the dampers. They are real dampers, not just springs. And they have two springs (there is one inside the body of the damper)


Next is the steering servo. The planned one is not delivered yet, I mounted one I had sitting in my stuff, largely overkill for this buggy. I will replace it as soon as the one I chosed for this project is delivered.


Then I followed the instructions and added the front triangles (only one. I believe it is made on purpose to compensate the natural precision of the rear train  )


Then, front springs. Yes, springs. Their axe is dampened by a toric joint. I made an exception to my rule which is not to oil or grease external elements : here if you don't, as soon the triangle has moved up, it doesn't move back. So oil is needed on the toric joint to have a two way suspension (up and down versus up only).. Another secret feature of this legendary châssis...


Next is the wheels. The most difficult part of the build, at least for the rear wheel. With the right approach, it is a question of 15 minutes work (including the 20 screws and bolts)...


Next the wheels find their place...


Electronics was left. I started by positionning the RX, making first sure that the position would not be an issue to position the driver. Then I hesitated for a a while for the TBLE-02S: I will run lipo batteries (2S). I knew that a mod exists (ithis one: LANE Boys RC: Tamiya TBLE-02S mod for LiPo cut-off ), and I had everything at home to do it. I have few of those TBLE-02S sitting at home doing nothing, and thought about trying (worst case scenario, I break it and use another one of the sitting ones). Took my stuff and start to butcher the ESC.


Few minutes later, that was done. Not really clean, but it is done.


I then started my tests. First statement, it works the same way as before (it's already an indication : it seems I did not break anything). That being said, test lipo cutoff with a 4200 mAH battery and a 540 motor will take some time, and I didn't succeed to finish today. At the end of my session, the battery was close to storage charge, so I let it this way, and decided to pursue my testing tomorrow morning....

Remains to do : led lights and paint (hard way :-D)

A+
Marc

Nicely Done  I loved seeing the 20kg steering servo in there 

Nicely Done  

 I loved seeing the 20kg steering servo in there  

Definitely overkill :-D (both on course (270°) and torque - End points are limited around 40%). It will be 3kg plastic gear servo at the end. (And I'm the same man who told yesterday a guy this servo would be overkill for Grasshopper on FB, and would damage the front end if he forget to set the end points properly - Do what I say, not what I do :-D). The real reason is the build was planned to happen another week-end, but I was stuck at home waiting for an important phone call, so had to do something, and made some anticipation...

Anyway, the main part is still to come : paint will take time :-D

Lipo on the savoyarde should be nice. Be carefull. You'll have an ex tamiya and kyosho official pilot . Kill him.

BITD I knew someone who insisted their "special" suspension mods made their Hornet competitive against the Schumacher Cats, RC10s and so on in the 2WD class. It wasn't, not even with the "carefully" chiselled open & rewound silvercan, and the extra Ni-Cd cell they'd hidden in the chassis.

You'd think that blatant cheating would have been found out, but their lap times were still so much slower than everyone elses, I guess no-one checked. Or they all knew, and just thought it was hilarious that the cheater was only managing 2 laps for everyone elses 3. Or 4.

From what I remember, the front suspension was always fully compressed & the front wheels were in snowplough formation, and with every bump of the rear end it would take 45 degree tacks across the track - same as every stock Hornet/Grasshopper beign run offroad, ever.


A race with just Hornets though, that makes a lot more sense. From "racing" Lunchboxes, I know that hilarity ensues - and trying to make the thing handle properly is actually detrimental to the fun.

I did mean to post something semi-useful - in a class full of identical cars, apparently it's useful if the paint is on your car stands out, and allows you tell which way it's pointing

 

stingray-63 wrote:

Lipo on the savoyarde should be nice. Be carefull. You'll have an ex tamiya and kyosho official pilot . Kill him.

Not sure I want to "kill" anyone in a race... Actually, not sure I can even :-D
I'm not a race driver. I'm going there for the fun :-D
While trying the second cutoff mod (on another TBLE-02S), I did start to understand how the Hornet works. I can report a success for the Lipo Cutoff at 6.7V. (Hint, after you've soldered the 22 KOhms resistor to the board, if you measure the resistance, it should display about 6.8 kOhms - was not the case for the first one - will try to redo it better this time)
 

Non-existant user wrote:

BITD I knew someone who insisted their "special" suspension mods made their Hornet competitive against the Schumacher Cats, RC10s and so on in the 2WD class. It wasn't, not even with the "carefully" chiselled open & rewound silvercan, and the extra Ni-Cd cell they'd hidden in the chassis.

You'd think that blatant cheating would have been found out, but their lap times were still so much slower than everyone elses, I guess no-one checked. Or they all knew, and just thought it was hilarious that the cheater was only managing 2 laps for everyone elses 3. Or 4.

From what I remember, the front suspension was always fully compressed & the front wheels were in snowplough formation, and with every bump of the rear end it would take 45 degree tacks across the track - same as every stock Hornet/Grasshopper beign run offroad, ever.


A race with just Hornets though, that makes a lot more sense. From "racing" Lunchboxes, I know that hilarity ensues - and trying to make the thing handle properly is actually detrimental to the fun.

I did mean to post something semi-useful - in a class full of identical cars, apparently it's useful if the paint is on your car stands out, and allows you tell which way it's pointing


 

Well that's for sure one rational for a hard work paintjob definitely off from the box art one.

Anycase, the Savoyarde registration information says:
- dampers are free (you can go for some fancy front dampers if you want, rear as well)
- chassis must be GH/GH2 (lunchbox is also confirmed as authroized)
- Motor 540 silver can
- Lipo authorized
- electronics is free

I believe the only rationale for the race is fun, fun fun...

While testing the lipo cutoff mode with the Hornet chassis without body, I already started to sens a few things:
- the rear train rotation is a lot of fun, any bumps will send you anywhere else than you initially thought, even if it affects boths rear wheels the same way
- full throttle  while steering is followed by a strange dance of the rear train
- it is surprisingly efficient on grass compared to the DT-03, and I'm not exactly sure for the reasons for this, as it defies logic

Not sure this post is useful, but at least, it is fun :-D

Tires are for something....

stingray-63 wrote:

Tires are for something....

Not sure it is the tires... I believe the natural rebound of those chassis' suspension really help as well, as this machine is actually moving in the grass by doing jumps rather than a smooth moving...