Help with new project.

Hey I would like to discuss step by step (base, conversion needs, elecs, etc) A new project for a noob. I will try not to ask dumb questions.

First, my options. I am getting the money together, got most of it to get a new nitro vehicle for a conversion. My main choices are the Rc8 because I like it more than any other buggy for some reason and buggies are awesome. Some sort of truggy, like a kyosho inferno, the cheap one or a larger on road.
Also considering a crt.5 but would rather have the extra size. Trying to stay under 500$ with this part.

Second about mechanical brakes. In your own words ( very essay like)
why would you use mechanical brakes when the esc has braking function that you can tune?

I will ask about electronics once I decide what platform to start with because they will most likely greatly vary.

Please dont be shy. please help me out with your opinions and experiences.

Just remembered to ask. A muggy would be like an lst2 with center diff right? Elecs just went up to power something this big lol

[wallot]

in 1/8 buggy you have center diff and if you use ESC brakes you will brake only one axle thanks to the way center diff distributes power with one axle locked (of course unless you have the diff filled with very heavy fluid)

mechanical brakes will alow you to brake using both axles and tune strenght and bias of braking.

ESC braking allows you to set just how stong the brakes will be.

for serious racing mechanical brakes are probably a must, in rest of the cases ESC braking will be ok.

I'd go for 1/8 truggy as buggies are really just for tracks thanks to very low ground clearance. LSP pro is very cheap and durable truggy.

[Arct1k]

Most people started with using motor breaking however if now a move towards mechanical breaks - main reasons seem to be:

- Smoother
- Front / Rear bias
- Less load on ESC hence runs cooler
- Saves battery

The whole buggy/truggy choice will cause lots of debate - most of the higher end ones seem to be great platforms CRT Pro, MBX5T Pro or 8T or their buggy counterparts. I'm not sure you can go wrong with any of those.

Electronics is honestly a money question - how much do you want to spend. The ferrari option is an MGM160 / Nue or Lehner the pontiac is a MM & Feigao.

Lipo / Lion is the way to go on the battery front - but there is again a debate on HV which is the trend. This offers lower amps and cooler setups but elecs are generally more expensive.

Thats my 2c summary

Cool. Yeah I would say truggy would be better for me driving style wise. I doubt it will see much racing time but maybe a few laps on a track. I have a mm already. If I got the crt.5 all I would get was a feagio 8l or something. But something bigger I am looking at escs. for a mgm I doubt I would be going high cell count 8s would probably be the highest and very high for me 4-6s would be my ideal set up. I cant recall exactly but I think I saw 8s 140 amps? That sounds good. Motor wise I have no clue. Besides I looked on Finedesigns site just for options (heard some bad stuff) and there was a neu\nue I believe or hacker, the size of a coke can, and then bigger. lol just joking on that though,

Didnt mean to double post, deleting other.

On brakes, I would like to be able to tune front and rear bias. These run on one servo?
As of now I am almost certain I will get the rc8. Has anyone heard any bad or things that would change my mind?



Ok yeah 160 was what I must have looked at. May I ask whatsup with the BK controllers? like are they being discontinued or something? What about the hydra escs? do they have reverse?

Still thinking of having Griffinru stick two mambas together, but thats about the same price as a non hybrid with the same specs.

[Arct1k]

Brakes - yes one servo I think you manage the bias in the linkages.

Can't comment on RC8 have a Mugen MBX5 (MSRT) and a X1-CR.

BK - I believe support issues

Griffinru - an option but I like the support from Castle - You could just do the cap mod.

Rgds

[BrianG]

Advantages to using ESC/motor brakes:

• Motor braking is easier to install, requires less space, and lighter since there is no servo, mount, linkages, brake pads, etc.
  
  
• Mechanical brakes can suffer from brake fade during the course of a run.
  
  
• Mechanical brake pads wear out from friction.

However, there are several reasons to use mechanical brakes instead, some of which have already been mentioned:

• More tunable, especially when using a center diff. Bias can be set seperately from front to rear.
  
  
• If using an autoshifting two speed tranny (like the Revo, Savage, GTP, etc), you can't use motor brakes because of the OWB on the first gear. So, mech brakes are a must.
  
  
• Motor braking is hard on the ESC and batteries. When braking, the motor can induce high voltages back into the ESC and then to the batteries. This makes the ESC heat up more and is not so good for lipos (which are more voltage sensitive than NiMHs). If using a high voltage setup (over 4s), you really shouldn't use motor brakes because of this IMO.
  
  
• Greater selection of ESCs. Since you aren't using the ESC/motor for braking, you can use aircraft ESCs (many don't have brakes), which are often quite a bit cheaper. You might need a pistix adaptor to translate the throttle signal though...

Would the throttle inputs need to be translated due to the step and stay of the airplane stick radios vs. the auto return of the pistol? Also Arct1c, I dont know of the cap mod. Are you referring to his "stage one". I am sold on mechanical brakes. As I wont be racing competitively I am not too worried about them fading. Pretty much decided now on the Rc8 with the conversion parts needed from RCM. Not sure on esc because not sure what the best deal would be. I would like to get something nice, maybe a Air esc with no brakes but not sure on reverse. I may not need it since I have lots of space but as it isnt subtracting from weight and such like removing a gear and all that why not. Whats a relatively cheap plane ESC to get me started? I still have to get a new charger and a couple starter lipos, most likely 4s with nice milliamp rating. Would a feagio run it sufficiently for a while til' I upgrade and I can put the feagio in something smaller? When I buy better electronics for this I want a little more than I need, in case I get something bigger.

[BrianG]

The throttle signal varies from 1ms pulses to 2ms pulses. From what I understand:

An airplane min throttle is 1ms and max throttle is 2ms.
A car reverse/brake is 1ms, neutral is 1.5ms, and max throttle is 2ms.

So, the pistix adaptor has to convert a pistol radio's 1.5ms neutral signal to 1ms while still providing a 2ms pulse for max throttle.

I hope that made sense.

As far as ESCs are concerned, the sky's the limit. There seems to be a much greater selection of these and they're cheaper to boot. Even the Quark 125 air ESC is quite a bit cheaper than the Quark 125B car ESC, and they have the same specs.

Okay, I might get a lipo charger tommorow, then it would make it a little easier to determine parts. I have another esc and motor to buy. 65amp and out runner,

Just threw something in the speed calculator, wanna clear a few things up. About how big is the average buggy tire? About how much does a converted buggy weigh?

I selected 43/13 for the diff ratio,
direct spur 1 to 1
46t spur
then I am not sure what a good starting point is so I dropped in a 16t lol
4s lipo, 14.8 they are about 3.7 a cell right?
I selected a 6xl for a starter pretty much at random.
I also threw in 5 inches even for tire dia. becasue I think 2.2 bugg wheels and tires are about 4.0, not sure though.

Spur/Pinion Reduction Ratio: 2.88 : 1

Total Reduction Ratio : 9.50962 : 1

Tire Circumference (?): 15.71 inches (398.98mm)
Total Motor Speed (?): 41129.2 RPM
Final Vehicle Speed (?): 64.33 MPH (103.34km/h)
Effective speed rate (?): 4.35mph/V (6.98kmh/V)
Calculated Loaded KV value (?): 2779

I figured going over the recommended rpms a little is okay. Wouldnt it cause a little extra heat? I thought the top speed is a little high though. I was only shooting for 50 at best out of this. I think maybe an 8xl would be the ticket.

[jhautz]

Typical buggy tires are from 4.25 to 4.5 inched diameter. There are smaller and larger ones out there, but that is pretty typical

Rather than running a high rmp motor, with the cheaper stlye motors like the Feigao I find its better to run a lower RPM motor and get your speed with the gearing. I would recomend shooting for closer to the 30,000 rpkm range to help keep the motor cool. In my experience they tend to get hot quickly at more than that. A higher end motor like a Neu or Lehner could easily be pushed to 40,000 rpm without to much heat issue.Id say shoot for an 8xl on the 4s and you will have a solid setup that you can reliable gear for 40-45mph and not have alot of heat problems.


I also think that in general, shooting for a 60+ mph setup with 4s is a little aggresive on 4s for everyday running. You could probably gear it that way for a speed run or 2 but running it for exended periods like that will just overheat everything. I think on 4s a resonanable all around setup would be in the 40-45 mph range. If you want more speed than that plan to run more voltage. probably 6s if you truely want 60 mph reliably. That kind of speed isnt good for anything except bashing. You will never see those peeds on the track and anything over 40 is pretty much a waste.