TOPIC:

vara351 wrote:

...is there a way we can discuss this further without posting it in the forum?

Yes indeed - click on a user's name, & on the next page hover over "messages" & select "send message"

SUSPENSION MODS
I think the standard Monster Beetle suspension is too firm. There could be improvements in the car's handling and traction by fitting softer springs. I tried a few different springs that I had and eventually settled on fitting some 'hard' springs from the cva short shock set up front, and the standard beetle front springs in the rear. (The 'hard' cva springs are still noticably softer than the beetle springs.)
With the softer spring rates the damping now seemed inconsistent and tight. I pulled the shocks apart and found some mismatched pistons so I raided my spare parts and found a set of 4-hole pistons for the front and 2-hole pistons for the rear. I then re-filled the socks with soft #400 oil and fitted them to the car.
The front still felt tight and I believe this is because the front shock was mounted too far forward and the suspension arms would try to twist rather than push straight up on the shock. I wanted the shock to be above the front arms so I made a cutout in each front upright for the bottom of the shock and mounted the top of the shock to the back of the shock tower using some leftover spacers from the short shock set.







The shocks still felt too tight and I eventually figured this was because the standard black o-rings in the shocks were gripping the shock shaft. I re-built the front shocks using some red o-rings and now they are much better. I will fit some red o-rings to the rear shocks when I get some more.

I am still waiting for my re-re Frog drive shafts to arrive so I can start the diff mod...

Still have to read the lastest posts. Just wanted to respond to the question about personal messages...
There is a shorter route than Jonny described - the button at the arrow below.


If you expect to be in contact with a member more often, you can create a connection by going to their profile page :


After doing this, the person can easily be found under the "Friends" tab.

Good thinking and modding on the shock setup.

I just fitted a new steering servo, a Hitec HS625-MG. This servo required a different fitting in the servo saver to the one I had, but I was able to use some leftovers from my Boomerang to build another servo saver. I then flicked through some manuals and it seems this is the same setup as the re-re frog uses.
Also replaced the under body guard and rear suspension sides with tougher re-re frog items.

Gearbox/Diff
My Frog upgrade drive shafts arrived, here is a pic beside a standard Monster Beetle hex drive assembly. The new universal shafts and dog-bones will be a lot stronger than the hex drives and cups.



I then attempted the "oldfrogshot screw mod" and managed to break the end of the 2.5mm tap off inside the drive cup spline. After a few curse words I was able to remove the piece of broken tap by carefully grinding away the spline around it until I could get a grip on the broken tap with pliers. Figuring I now had nothing to lose I drilled the hole out to 3mm and drilled the other drive cup out to 2.5mm and ran a 3mm tap through it. I was a bit worried the wall thickness of the spline would be a bit thin for a 3mm hole but after seeing the finished job I am confident it will be fine. In fact I would recommend anyone else who attempts this mod to use a 3mm screw. I do not believe there is any advantage to using the fiddly, uncommon 2.5mm screw.



My modified drive cups. Fortunately the splines go in the diff gears a fair way so my "shortened" spline will not be a problem. I then loosely screwed the diff together using a 3x30mm countersunk screw with thread lock on the thread and plenty of grease on the head. Hopefully the drive train will now be strong enough to cope with brushless power.

Nice work on the drilling & tapping

Here are a few more quick mods...

I made some castor rod bushes out of nitro-car fuel line, this may take up some play in the front end. It probably will not make a noticeable difference while driving the car but it does feel better on the bench.




When using the re-re Frog swing arm supports the holes in the ends of the swing-arm are left uncovered. Any dust, dirt, gravel etc that finds its way into these holes could end up inside the gearbox. I got some small plastic plugs from the hardware store and glued them in the holes in the swing-arm to block them up.

My project Monster Beetle is now officially a brushless!!!

I decided to try an EzRun 9T/60A combo. I chose the 9T motor as my Midnight Pumpkin has a 10T and I figure the Monster beetle should be able to handle more speed as it has a longer wheelbase, better suspension and less unsprung weight than the Pumpkin. Both cars have the same (or very similar) gear ratios although the Beetle does have taller tyres. I wanted a motor with the 380 sized armiture over a true 540 because I think it will still produce enough torque for this chassis without placing unnecessary strain on the driveline. I stole the Sanwa 2.4GHz receiver from my Durga.



Time for a road test - Boy does this thing go!! It is too fast, I will have to fit a slower motor. Any sudden movements with the throttle would often result in uncontrollable power slides (even on sealed roads) and high speed steering or braking is fraut with danger as the buggy rolls easily. With this combo one could make an entertaining You-tube clip but for me it was no fun watching my pride'n'joy do barrel rolls across the ground.

The rest of the car was great. The modified diff and gearbox did not present any problems and the suspension worked fine although the rear spring rate did seem too soft. For the next run I will re-fit the standard rear springs and try the 10T motor from my Pumpkin.

vara351 wrote:

... no fun watching my pride'n'joy do barrel rolls across the ground. ...

Ouch

I'm not sure a 10T is going to make much difference in that regard though