Green Machine II

[fasterthanspeed]

Here is my speed challenge r/c car.
Its not complete. Still need throttle/brake linkage setup, and electronics need to be setup.
Im hoping to drive it this weekend.

The engine is a AXE Rossi Maranello.
The rear end is from an R40 I wasnt using.
The front end is from a rc10l4.
I will be using a futaba 3pk fasst radio system.

http://i120.photobucket.com/albums/o187/speedchallenger/DSC01189.jpg
http://i120.photobucket.com/albums/o187/speedchallenger/DSC01188.jpg
http://i120.photobucket.com/albums/o187/speedchallenger/DSC01187.jpg
http://i120.photobucket.com/albums/o187/speedchallenger/DSC01186.jpg
http://i120.photobucket.com/albums/o187/speedchallenger/DSC01185.jpg



Sorry for the dark images, but my camera isnt very good.

[fasterthanspeed]

The body will be made from kevlar. I plan to start the body this weekend.

Also, I was thinking, Modman does the gyro help out alot? If so, is this agood one?
http://cgi.ebay.com/JR-G500T-GYRO-FREE-SHIPPING_W0QQitemZ330140788936QQihZ014QQcategoryZ3 4056QQrdZ1QQcmdZViewItem

[insomniac]

thatnks for showing us your car! It looks a little lopsided, have you put ballast on it to even it out?

[Mod Man]

Fast,

Yes that is a good gyro and a good price.

Here is my opinion and experience with gyros. Bear in mind, I have been designing and manufacturing helis for 4 years now and have gone through ALOT of gyros;

Gyros help a huge amount under accelleration. They keep the nose of the car pointed straight and allow you to get on the throttle sooner, therefore the car has more time to wind out. Now, that is the good news. The bad news (there is always bad news with any mod), at super crazy speeds, the gyro has to react (and the steering servo) extremely fast to keep the car pointed in the correct direction. This means that if the gyro and servo setup are not fast enough for the speed you are going, the steering will get vague and you may experience steering wag above a given speed.

One example;

My GY502 gyro was phenominal in a heli. In my Tamiya Dark Impact, it was also wonderful even up to the car's 64 mph top speed. However, in my TC4, it begins to feel vague and I even had a radio glitch that shot the car off the road above 90mph. That was it! So, I put my GY611 gyro and matching servo on (all in one kit). That is one of the fastest gyros in the world and THE fastest servo available. That setup is killer!

Now lets apply that knowledge to your car;

In my situation, I need a radically fast gyro and servo. Part of that is the neutral steering my car has with a 50/50 weight bias and equal width tires front and rear. So, I have alot of steering power at speed. So, any gyro input becomes alot of movement of my front end, requiring a hugely radical servo and gyro.

In your situation, your front wheels will not have as much steering input due to their narrow profile. So, a slower gyro and servo may work fine because if they are not 100% accurate, your front tires are not going to translate as much input into the front of your car.

To sum it up, that gyro and servo many be great for your car, but it would not be fast enough for my 4WD car due to the higher steering sensitivity.

Sorry to overload you with info. But, that is a tough question to answer.

Oh, I like your car, by the way. You will need quite a bit of downforce at the rear to get all that power to hook and then you will need nose downforce to keep it from rotating over at speed.

You did a VERY good job designing and laying everything out. The chassis looks clean, straight, and very high quality. I am impressed.

If you would like a piece of 3mm thick carbon fiber to make a lower chassis out of (using your aluminum chassis as a template), let me know.

Matt

[fasterthanspeed]

Insomniac, the car is perfectly balanced and straight. It just looks uneven because of the pics.

Thankyou Modman for the information and compliments. I did the best I could with what I had, as I am only 16.
Ive already got carbon fiber. I just dont have the tools to cut it.

Brian

[skylineTT]

once again, the car looks great. cant wait to hear run results.

[Mod Man]

Brian,

Use a Dremel with a cutoff wheel. CF cuts like butter that way. ;)

Matt

[ajlovering12345]

Hey that looks great!! You have cut everything down to just whats needed to go really fast! Whats the roll out and est top speed for 40,000 rpm?

Great job!

[fasterthanspeed]

Thanks.
At 40,000rpm its capable of 136mph. The motor is rated at 52,000rpm and 3.66 hp.

Ill weigh the car either today or tomorrow.
Need to go purchase a scale.

[Mod Man]

Your horsepower is a very good match for your car size and what you are looking to do.

Again, I am impressed with your design. and execution of the car.

If you can do this at 16, you have a bright future ahead. ;)

Matt

[fasterthanspeed]

Thanks for the compliments.
I just recieved the kevlar through the mail a cople minutes ago!
Im so happy.
Also, how would I calculate the cars rollout?

[fasterthanspeed]

I just got the scale. The car weighs about 52 ounces.

[fasterthanspeed]

http://cgi.ebay.com/Turborix-High-Performance-GY400-Head-Lock-Gyro_W0QQitemZ200122784179QQihZ010QQcategoryZ34056 QQrdZ1QQcmdZViewItem

Would this one work well to?

[Mod Man]

I would not go with that gyro. That is a cheapo gyro.

The other gyro you were looking at was far better.

Matt

[fasterthanspeed]

http://cgi.ebay.com/Futaba-GY401-Gyro-w-SMM-Technology-NIB_W0QQitemZ140132585749QQihZ004QQcategoryZ34056Q QrdZ1QQcmdZViewItem

How is this one? I just dont want a used unit.

[ajlovering12345]

I have that gyro in my heli. Its really good in the heli.

Im not going with a gyro as I think I can setup the car to track straight. I have driven 1/8th cars at 70 mph and they are as straight as an arrow. :teacher:

[ajlovering12345]

I was just seting up my Tx unit.

I have configured the dual rate steering so that its 100% on rate one and 20% on rate 2. When I hold the button on the grip it goeas from 1 to 2. This will be usefull so I can turn around then on the speed run hold in the button.

I have also setup the throttle servo speed to 0%. I thought it wouldnt move but takes about 6 second to go from 0-100% This is my launch control

I'm sure you can do this on most high end handsets

Cheers

[Mod Man]

http://cgi.ebay.com/Futaba-GY401-Gyro-w-SMM-Technology-NIB_W0QQitemZ140132585749QQihZ004QQcategoryZ34056Q QrdZ1QQcmdZViewItem

How is this one? I just dont want a used unit.

I have a bunch or 401s. They are good gyros. I have not run one in a car, though.

Matt

[fasterthanspeed]

Im gonna go with a gy401 gyro, and a s9650 servo.

[Mod Man]

I have a heli that runs the 9650 with the 401. That is a good choice. The perfect combo is the 401 with the 9253 or 9254 servo. However, that servo is standard size (big). However, it is faster and more accurate. The 9650 is the best choice in that size range. :)

So, when's the first run?

Matt

[ajlovering12345]

I just tested the 3PK with 40 mhz and 16.5 volts and the range is the same as before. I will stick with the spektrum

[Mod Man]

Oh, bear in mind, you will need a third channel on your transmitter for the remote gain on that gyro.

Matt

[Mod Man]

I just tested the 3PK with 40 mhz and 16.5 volts and the range is the same as before. I will stick with the spektrum

Cool, I really like my Spectrum. But, I have heard the longest range, by far, right now is the new Futaba 2.4ghz system. I am still running my DX3. But, I may go to the Futaba.

Matt

[fasterthanspeed]

yup, i got a 3pk
tomorrow hopefully.

[ajlovering12345]

Cool, I really like my Spectrum. But, I have heard the longest range, by far, right now is the new Futaba 2.4ghz system. I am still running my DX3. But, I may go to the Futaba.

Matt

Where did you here that? B4Maz had that set and only got 400ft range!!

[Mod Man]

Hmm, not sure I can share that info. ;)

Matt

[fasterthanspeed]

Its all done.:D:eek::D:flame::driving::p
just waitin for rx pack to finish chargn.

[ajlovering12345]

What type of clutch bell is that again? I was looking for one today but cant find one

Cheers

[fasterthanspeed]

Just got in from startin the engine. First time was terrible. First the clutch slipped on the engine shaft, got that tightened up, then the starting wheel was salipping, fixed that, finally got it started, then a c clip fell off the tranny shaft allowing a bearing to come off and the 1st gear pinion unscrewed itself. Good thing i bench started it today. Ill be getting mor c clips tomorrow and resume braking in the engine.

later,
brian

[ajlovering12345]

I had the same sort of problems the first 5 times out and even saw the 2nd speed clutch work loose on my last run. Its not like running a kit car is it!

Let us know how the first run goes

Cheers

[fasterthanspeed]

I just got back from ultimate hobbies. I found out that my servos arent compatible with the reciever. So i bought 2 futaba sertvos. A s9650 and i forget the other. Also got that c clip.

[ajlovering12345]

Just before I left for Lagos I made a 6 cell RX pack. I tried it in the car with the Spektrum but didnt test the range. So now I have 12 cells in the TX and 6 in the Rx so this should help

Damn I'm climbing the walls here itching to get back to the garage!! AAAAHHHHHHHH!!!!

[Mod Man]

Tell me about it! I just rebuilt the rear end of my car and modded the body. I am itching to get out and run it.

Brian, we are dying to hear about your first good run! :)

Matt

[fasterthanspeed]

Nothin. I put in the new throttle servo, started it up, reved it up a tad and the servo gears stripped

[ajlovering12345]

?? Did you set the EPA ?? seems strange even if the servo had stalled.

[Hard Case]

Brian
Good effort on your car. Does it have a name?
What's the body look like?

Suggestions; (if you're open to them)

Metal gear servos---only
Raise your throttle servo to Line-up to the though on the carb
Never use a Kimbrough servo saver
Take out your bump-steer
Add 14' of caster
1/2' rear tow-in
&
It looks like you will need taller gears (not sure though)




Nice front wheels.. :)


Nic

[fasterthanspeed]

I just got a new servo saver and got a metal gear servo. I have a 27t pulley and a 32t custom solid diff.

Thanks.

[Mod Man]

Good call Nic.

Brian, I gotta repeat what I said earlier. I am happy to see how good a job you are doing on your car. Nice stuff!

So, what rear toe does the car have? It looks from the pics as though it has toe out (that may be an optical illusion, though).

Matt

[fasterthanspeed]

It was at zero. Maybe im wrong. Not that difficult to change.

[Mod Man]

Gotcha.

I would agree with Nic. 1/4 to 1/2 degree rear toe in is best for stability and ease of driving.

So, the weekend is here! Are you going out for some testing?

Matt

[fasterthanspeed]

Oh ok. I hope to. I still need to work on the body. Havent found a Place yet thats flat and long enough.

[Mod Man]

Man, I hear ya on that. I still deal with 1300 feet total. I only use about 1000 feet of it total. So, 115mph is the most I can achieve in that distance (accelleration and braking combined).

You sould be able to do some testing without a body. Aerodynamics really kick in at about 70mph. Below that, you could run without it. ;)

Matt

[fasterthanspeed]

Just got in from first run. I got about a half a tank out of it before problems.
I got some 25-30mph runs at 1/8th throttle. It accelerates to 30mhp in like 20 feet.
Well after runnin it, my elecs started not to work.
I then put it on the starter box, hand revved it, put back on idle, then it revved to 1/2 throttle for like 30 secs.
Everything held together wonderfully. I guess my custom drivetrain works good.

[Mod Man]

Glad to hear it!

Did it accellerate stable or was it a handful to drive?

Matt

[fasterthanspeed]

Just got in from another run. Everything runs great. Only one problem, it has very little traction. Tomorrow ill be getting traction compound and possibly Futaba GY401 Gyro. If they have them in stock.

[Mod Man]

The gyro will really help with accelleration control.

I kind of figured traction would be an issue. Moving weight back will help too.

Looking forward to more testing!

Matt

[fasterthanspeed]

Ill try to get a vid tomorrow. Hopefully some pix of my dads speed challenge rc car. His is brushless lipo. Its a budget speedster.lol.

[Mod Man]

You know, from what I see and hear, this top speed thing is becoming more popular, but also harder to keep up. I still have no clue how fast my car can really go. Yet, I have the feeling the gap between the fast guys and the world class speed cars will widen ever further very quickly.

Matt

[fasterthanspeed]

Oh yeah, its called GREEN MACHINE II. My first car was green machine. Thought it would fit the car. As it will have a candy apple green body.


Brian
Good effort on your car. Does it have a name?
What's the body look like?

Suggestions; (if you're open to them)

Metal gear servos---only
Raise your throttle servo to Line-up to the though on the carb
Never use a Kimbrough servo saver
Take out your bump-steer
Add 14' of caster
1/2' rear tow-in
&
It looks like you will need taller gears (not sure though)




Nice front wheels.. :)


Nic

[fasterthanspeed]

Just got in from another run like 30 min. ago. I found out that a set screw in the diff came lose allowing one wheel to get no power. fixed that, did a couple more adjustments, work good. only slides on fast sharp turns, and luckily its for straight lines.

[fasterthanspeed]

This morning I found a place to run my car. Its a main road for industrial use. They just paved it like 6 months ago. So its pretty smooth. Ive got close to a half mile of usable runway. The mold for the bod is half way done. I hope to be laying the kevlar tonight or tomorrow sometime. This body is alot easier to make then last years. Less lines.

[Hard Case]

Looking forward to seeing it...........


N

[masterchief06]

Three words: USE A FAILSAFE. Given your luck with electronics and the questionably range of today's radio systems, I would make sure that if your car got out of range, it didn't continue that way. Imagine the car that you've put this much hard work and time into running away from you uncontrollably at "World's Fastest RC Car" speed :eek:. Good luck to you, and the car looks incredible.

Mike

[fasterthanspeed]

Ive already got a venom failsafe on it.
Thanks for the compliments.
My family dog got hurt 2 nights ago so that set me be back by about a day. The mold will be all done today.

[ajlovering12345]

Brian

I talked to Mirage and they told me the RS4-3 2 speed clutch bell doesnt fit on the V6 clutch as the plate has to have room to move forward to engage. How is your fitted?

They also do different shoes with the black ones being the most aggresive.

Cheers

[fasterthanspeed]

I just got the gyro setup. Im almost ready for a speed run.

[Mod Man]

Looking forward to it!

Matt

[ElectricThunder]

Lemme know how it goes via AIM dude!:D (Although, I may not be on much tomorrow.)

[fasterthanspeed]

Lol ok. Ill be doing the test in the evening, because itll be really hot tomorrow and my dad would have to take me to the area to test it.

[fasterthanspeed]

I just got in from my first long distance run. It did good and bad. i drove it for 1/2 a tank ran sweet, gyro made it run perfectly straight. Thank you Matt for the selecting of the gyro and rcdude for helping me set it up. then i let my dad drive it, he did 2-3 passes, on the last pass he hit a small rock he over compensated and hit the curb, the exhaust ripped off, got it back together and was about to run it again and then found out a rear axle was bent.
Over all it went very well. I estimate it went 60-70 on 1/4 to 1/3 throttle. Remember this is an estimate not the actual speed.
Brian

[ajlovering12345]

Sounds good Brian! You need to get the gremlins sorted out before the event so fix it up and get back out there.

Best of luck

[Mod Man]

Hey Glad to hear it! Excellent results! :D

Matt

[fasterthanspeed]

Ive just finished fixing and re adjusting stuff on trhe car. Ill do another run this evening. Ill try to remember to shooot a vid

[fasterthanspeed]

I have a question. At about what speed should i have 2nd gear kick in?

[Mod Man]

When the car seems to need it.

Basically, 2nd gear should kick in when the engine really starts to wind out.

Matt

[fasterthanspeed]

Well today was the worst run of them all! i never was able to run. I got it started, hooked up the power to all the elecs. and it started to glitch badly. So reset the radio and still glitched. By then it was to dark to even run it. So i decided just to let it idle. It then idled eratically. so theres an air leak either in the fuel line or head button. I will be doing another run tomorrow and get all the probs sorted out.

[ajlovering12345]

Hey Brian. Forget about your V6 clutch! I just made an aluminium Centax clutch shoe and it works like a dream. Before I could not run one engine on the car without ruining the shoe in about 5 mins and when all 3 engines were running I still got slip. I jus tried one engine with the new shoe and it grabbed instantly and the clutch didnt event get warm.

I will make a few more for the other engines and try it on the road.

Cheers

[fasterthanspeed]

Ive decided to make a blog about my rc car. Ive got an update. So heres the link.

http://mywfrcc.blogspot.com/

[fasterthanspeed]

A VERY BAD UPDATE!!!!!!!!!!!!

http://mywfrcc.blogspot.com/2007/07/oh-carnage.html

[masterchief06]

Man you are having a LONG streak of bad luck! Good luck man, and strap everything in tight!

Mike

[Mod Man]

That stinks!

I had the same thing happen to my 1/8 scale off road car. That is really a pain. Nitro cars have vibration to deal with. That is frustrating to say the least. I am glad you have new parts coming.

It will all get sorted out. But, it is frustrating in the mean time.

Matt

[trailranger]

Shoe Glue the plugs in place, I heard that dell uses a silicone glue to keeps
plugs and wires from popping out durring shipment, and shoe glue peels off with a little force. I don't own a dell to verify. I have always built my PC since 1995.

[fasterthanspeed]

Well I only got about 62 mph. because, there is a little c clip that holds the spring on for the suspension, that fell off at about 50mph. I wasnt able to find the new spring in the box in time so i rapped it up.

[masterchief06]

62?!

Well, I guess better safe than wrecked

Mike

[fasterthanspeed]

Well I have the new design for next year complete
I just need to make some parts
It should hopefully be running in about 2-3 months
Then I gotta make the body