Scale 1/8 buggy
 

Hi Peeps, I'm thinking of making a scale(ish) 1/8th scale brushless buggy.

Does anyone make scale rally or offroad bodies to fit 1/8th buggys, (Wheels inside the arches not truck style)

I will quite possibly use a Hot Bodies Lightning 2 pro, as they are sold near me at a reasonable price without the engine, saving me the hastle of trying to sell it is this suitable for a brushless conversion? any mroe problems than the average buggy?

I have an feagio 8xl and 12 cells from a boat, but my boat is only a little oveer 2kg and I hear buggys are well over 3kg, will the 8xl be enough for the heavyer buggy?

I heard a CC mamba max will handle 12 cells if you use a reciever pack or external bec, and its the cheapest 100A controller that Ive seen, and by a fair margin, so I'd like to use one if it isnt gonna melt. so is it enough for 1/8 buggies or do they mean 12x 1b1500s instead of 6x ib4200s on a little motor in a 1/10th?

What about brakes. motor brakeing heat up controllers, so will the mamba max only handle that kinda system only if I use the mechanical brakes, or is it up to the task of stoping it as well as making it go? I'd like to strip as much out of it as I can to save weight.

Ive been told that if you dont use a slipper cluch in a brushless 1/10th you will eat gears, do I need one for a 1/8th? or are the metal gears man enough for the task compared to the cheap plastic ones found in tamiyas, if I need one who sells em? I guess a tamiya one would smoke instantly with 12 cells and a 1/8th to push? the 8xl has a 5mm shaft.

It seems like all there is to it is than making a motor mount, maybe removing the brakes, maybe removing the spur and puting a slipper and new shaft on it, adding a mounting tray for a battery, mounting the esc, and extending the body posts?
Is there more to it than that that ive not seen?

I know its lots of questions but if you can answer any of them i would be gratefull. Paul

Welcome to the forums!

Not sure on the body. The lightning 2 pro looks like a great candidate for BL!

The 8xl will be more than enough to power the buggy. A Mamba maxx is perfect on 12 cells with a UBEC. I would reccomend a fan on it. The MM has great brakes, so no problems there.

Id try to use a Plastic spur gear for the center diff, and a 5mm bore pinion off mike.

Gearing
 

Glad the stuff I decribed will work well, at those budget prices hopefully it wont be too long before I can afford one. i was half expecting to hear that all that stuff wasnt suitable and I'd have to spend a lot more than that to make it work reliably.

Any idea how to gear the 8xl in a lightning 2 pro? ie what size spur and pinion, should I wait till I get the buggy then count the teeth and get direct replacements? or will I need to use a different size spur and pinion for a higher/lower than stock ratio in my set up?

What size is the spur gear? You will have to gear pretty high since its a 8xl on 12 cells.

If I go for a plastic spur like you sugest, I think the kyosho nylon ones fit (can anyone confirm this), RC-Monster sell them in 44 or 46 tooth versions, which would be better? if that fits mod 1 pinions he sells those form 10 tooth to 20 tooth excluding 17 and 19

thats quite a selection of ratios available if that stuff fits togeather on a lightning 2 pro

I have no idea what kinda ratio i am after tho, prahaps you can help me with a sugestion?

Can anyone help me with gearing? I downloaded Brian G's speed calculator but I dont have a copy of excel to run it on.

The 8XL is 2084kv, with 12 cells at 1.1v per cell thats 27,500 rpm

I would like to get a top speed of 40 mph on the 4.58" diamiter buggy tyres.

The plastic spurs are only available in 44 and 46 tooth but theres pinions from 10-20, so theres alot of potential ratios

I will have to buy both the spur and the pinion anyway, so I have no bias to use any particular one.

I just read that the 46 tooth pinion wont fit in the lightning without chasis mods, so I will have to use a 44 tooth spur.

You don't download it, you just enter the values right in the webpage...

The link is at the bottom of my sig...

Anyway, a 16T pinion will get you there based on the information you specified. BTW: the 8XL has a loaded kv of 1875. The value you posted is unloaded.

Sorry Brian, I must have been thinking of someone elses version of the software, and an inferior incomplete one at that? yours is easy to use and doesnt require any preinstalled software to function. Thank you for taking the time.

It looks like you used 1.2V/Cell for your calculations, that seems high to me, but I havent run round cells since 1700s, is that a realistic voltage under load?

You need to set the voltage per cell with Brians calculator, don't know what made you think it took 1.2V per cel?


A more realistic voltage is 1V (this is under a 60-70A load)

Thanks Serum, at 1v per cell I need a 19t pinion for 40mph, but as noone makes 19t pinions, should I go down to 18t ot up to 20t for the best comprimise between acceleration and speed?

Yeah, I would go for an 18, it will most likely give you the speed you want.

I ran my buggy on 14 GP3300's/7XL, it was calculated to go 60 km/h and it did 71 km/h

Ok I think I see what is happening here. The buggys speed is limited by the gearing and the motor is unloading, as it unloads its kv goes up and the cells put out more volts resulting in higher rpm and speed.

I guess thats why Brian used 1.2v/cell in his example, (loaded kv and unloaded V aproximating a medium load at a gear restricted top speed)?

In Serum's example, is his motor starting to unload at 60kph continue unloading untill at 71kph in no longer has any power to accelerate.

If he has room to do 71kph would he be better off, putting on a biger pinion so he doesnt start unloading untill 71kph to improve his 60-70 acceleration? or is it best to compromise that high speed acceleration to get to 60 qiucker?

Too much speed and you sacrifice acceleration and can get high temps.
Too much acceleration is wheelspin and a drop in speed for nothing.
Too much temps and everythine else becomes unimpotrant.

There must be an ideal compromise between speed, acceleration, and temps, 40mph was a noobs wild guess. Where do you with your experiance think it should be?

I know nothing of the limits of an 1/8 4wd buggy. What is the speed of a buggy that is totaly limited to traction, (and im guessing all buggys will have a similar finite limit) with a given torque (XL size motor, geared to suit). For example, if I was to gear a buggy for 10 mph, full throttle would give me wheelspin untill 10mph.
Would it do the same geared for 20? 30? 40?

Can anyone with experiance with an XL and mamba max (useing electronic brakes) tell me what loaded speed I can get, before I risk cooking something?

I think im learning a lot, but it's just a noobs crackpot theorys untill someone confirms or disputes them, or I prove or disprove them.
Paul

it took about 20-30 meters to hit fill speed.

You're welcome paul. There was effort made to make my version as easy to use as possible. :)

As to the battery voltage rating: I do understand that the battery voltage will drop under heavy load. But that load happens under heavy acceleration (anytime the motor is forced to change speed in a short amount of time). Once you get near the top speed, the rate of acceleration will be less, therefore less load and therefore less voltage loss, so you get closer to the nominal voltage. What I do is make a worst case and best case scenario. I figure everything using low battery voltage (~1v/cell) and then again at a more ideal battery voltage (~1.3v/cell). The real figure is usually somewhere in the middle.

Generally, you match your motor and battery voltage so that you don't exceed ~35k rpm. If using a low KV motor, you can use higher voltage. If you are using a faster motor, you use less voltage. Then, you try to gear approriately for the speed you want ... within reason. Usually, you get less losses using higher voltage and a low kv motor since current will be less. But there are usually limits to how many batteries you can physically fit, not to mention the capacility of the ESC.

If you are going to use this buggy for racing on an offroad track, then 35mph seems to be the common desired top speed. If on-road racing, you can go faster more easily since there is more traction control and the terrain is easier to accelerate on.

well as im trying to do this on a shoestring I have the motor and cells allready so the only variable is the gears, I hope thats enough. With a 44t spur and 16t pinion, I get 33-40mph from 1-1.3v on the lightnings 4.58" tyres. That seems good forf the off road set up.

The rpm is well under 35k tho at 25-29k, will this make me more likely to smoke anything?

What about for on road? I looked at on road wheels and tyres, they use the same wheel but are lower profile so they are smaller diameter, thus if i just fit road tyres to run in the street it will be slower than off road, so I will need to swap pinions with the wheels.

Can anyone recomend a rubber road tyre that is decently grippy but very long lasting to suit my budget over time, and tell me the diameter so I can speed calc it.

If I should gear for 35mph off road, how fast should I go on road, and still be able to run hard for the batterys duration, without smokeing anything?

Why wont a 46t fit? The stock should be a 50t, dunno why it wouldnt work.

Kyosho Inferno GT
 

nativepaul,

You asked about rally bodies. Kyosho makes a short-travel, rally-bodied version of the Inferno 7.5 called the Inferno GT. It comes with Subaru Imprezza WRC, BMW M3, Nissan 350Z, and Aston Martin DBR-9 bodies, and the bodies are available separately. Here's the Subaru model on the Kyosho site:

http://kyoshoamerica.com/carsandtruc...ars/31811B.asp

There's a whole forum for this car here:

http://infernogt.proboards102.com/

I read that the hole in the chassis needed enlarging, if stock is 50t of the same pitch, the diameter must fit, so I'm guessing the plastic one has wider teeth, but I have neither buggy nor spur yet so I can't say for sure.

As it turns out the 44t is a better match for my motor anyway, or maybe slightly too big for an on-road set up, dependeing on speeds and tyre size.

well I took the plunge and bought a lightning 2 pro earlier today, i guess by the weekend ill have it and get the measurements for the diff mount.
Does anyone know if the lightning 2 pro diff mounts are the same as the lightning stadium ones?

They sure are. You might have wanted to wait since the new Lightning 2 Pro EVO is coming out soon...

Yeah I've seen the evo but its bound to be more expencive and I'm on a very tight budget, also I'm no racer and the new shock towers with all the extra holes are more confuseing and uglyer. Lastly, (you'l probably laugh here) I prefer the looks of the Pro's purple anodized chassis to the Evo's dull grey hard anodized one.
No E-Clips sounds great but I hope I wont be reaching for the pliers very often anyway.
Its got to be a better buggy than the Tamiya Hornet my last scale car was based from.

Oh, it definately is. I have a LSP with a bunch of mods done to it and love it. There great right out of the box, but with a few mods, there even better. They can hold there own against the best.

What mods do you suggest? due to my tight budget I will probably leave it stock but if there are any cheap mods that are well worth it I may consider them.

Does anyone know where to get sturdy extra long body posts, at least 4inches tall?

Wow
 

I got my lightning 2 pro today, im realy impressed with the Build quality and smoothness of the suspention. I'm realy looking forward to geting it going, hope it wont be too long, i'll take some pics tomorow, my camera doesnt like low light.

It came with loads of nitro stuff that im gonna try and sell, how much should I be asking for this stuff? pipe, manifold, brakes, clutch, fuel tank, radio box.

Im also glad to see that it came with a 4way wrench and alen key, I thought I'd have to buy a wrench so I will probably use that cash for a set of ballraces for the steering, they are 6mmX10mmX3mm ar'nt they?

Looking for On Road tyres for it too, is there anything better than road rages? I'm after longevity primerily but grip is a good thing too (if I can afford them)
road rages seem to be 3/4trs the price of most other tyres except a wheel/tyre combo from Mantua Models (5th set from the bottom http://www.mantuamodels.co.uk/displa....asp?catid=122) those tyres look very nice (like goodyar eagle F1s), come in a hard compound and are the same price mounted as the road rages alone, but the wheels are just FUGLY, anyone know where to get these tyres without the rims?

PS how do I get it to say "click here" instead of the link address text?

Heres a few pics for you:-

http://i22.photobucket.com/albums/b3...Picture008.jpg
With body no decals yet.


http://i22.photobucket.com/albums/b3...Picture011.jpg
Started the metalwork allready, my dremel keeps overheating, is a tough alloy.


http://i22.photobucket.com/albums/b3...Picture013.jpg
The space I have for the motor mount, the chassis starts curving up just before before the mud guard although you cant realy tell with my camera.

Why not just buy the one Mike has in the store for the LSP?

It seems like the LSP chassis must be wider than the buggy, either that or it doesn't have turn-ups on the sides? It is 8mm too wide as standard, I'm in the dicussing modification possibilitys with mike at the moment, that last pic was so mike could see how much it needed to be altered.

The stock LSP chassis does infact have the kick-up on the side, and I thought to be the same width, only longer.

well as you can see from the pic its 40mm from the diff mount to the lip on the buggy and mikes mount is 48mm from the bolt center to the edge, so he is going to cut a radius on the bottom corner like it has on top for me.

And a few more pics:-

http://i22.photobucket.com/albums/b3...Picture014.jpg
I cleaned up up my metalwork and refitted it.


http://i22.photobucket.com/albums/b3...Picture019.jpg
Fitted the wing


http://i22.photobucket.com/albums/b3...Picture016.jpg
And put on the decals

Squee, what size alen key do the larger alen bolts take? (the wing bolts and shock mount bots etc) I gotta go get one.

I believe there 2.5mm and the smaller ones are 2mm.

Thanks Squee, I didnt notice there was 2 larger sizes, the smaler ones I was thinking of are about 1mm for the grub screws in the brakes, I will probably buy a whole set tomorow.

Snooch to the nooch.

Getting a little closer now, I put ball races in the steering and fitted the servo.
I re-formated my 12cell pack, I made up a battery tray from alloy angle section lined it with foam and cut some carbon tube chassis standoffs, but I'm waiting for longer bolts to fit it.
Just an order from RCMonster and it will be runable, then the bodywork starts.

Some more Pics for you.
http://i22.photobucket.com/albums/b3...Picture023.jpg
The battery tray.


http://i22.photobucket.com/albums/b3...Picture024.jpg
In position.


http://i22.photobucket.com/albums/b3...Picture020.jpg
Looking a lot less bare than it used to.


http://i22.photobucket.com/albums/b3...Picture026.jpg
everything but the body, spur pinion, motor mount, mamba max and ubec.

While I don't generally like purple, that color contrasted with black does look nice. But, you gotta color your batteries though - blue clashes. :)

Does anyone know where I can get very long but still sturdy body posts from?

Depending on exactly how long you need them to be, I just used a nylon spacer on my Hyper 8 to raise the shell an extra 1/4".

I'm not 100% sure how long they have to be, I havent done any design work yet on the body, so it remains to be seen how much I can strech and squish a land rover and still have it look good, but I need at least 5" from the chassis for clearance, I think about 7" is what I'm looking for

Wow, 2 extra inches?! :dft002: That's gonna sit quite high. Have you thought about using a truggy body? I know this is a buggy, but 2" is quite a bit...

Your right about the battery heatshrink it does look wrong, but the only other heatshrink I have is either clear (and the cells are wild multicolour underneath)
or florescent pink.

I like the black and purple as well, and the red on the body clashes. I'm half tempted to strip the body and paint it black with a pair of purple stripes down the middle like the stripes down a ford GT40. I have a set of black road wheels for it allready and with a set of black springs I think it would look awesome (if theres a good body paint match for purple anodizing, anyone know?).

But a set of springs and 2 cans of paint goes against my budget and it will be hidden most of the time anyway, I was planing on my oft used black and gold scheme for the scale body, but maybe purple/black and I have enough left over to do the inner body too.

Ehe Brian, thats not a mis-type on the thead title, I did mean scale 1/8th buggy not 1/8th scale buggy, truggy boddies are way too narrrow to get the wheels inside the arches.:007:
I will be making a badass bowler style racing landrover body to go over the whole buggy for a full scale look, although caricature scale due to streched width and probably lower height.

ps is there any way not to show that long link when I post a smiley?