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  1. #1
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    1/16 Mini E-Revo - Top Speed Build

    Some of you may remember I showed some early pics of a custom chassis I designed in the "Aftermarket Chassis" thread about a week ago. I decided to do my own build thread so others can see what I am up to. I've had my mini revo for a few months and have started to focus on getting the most speed out of it as possible. I had upgraded the stock ESC and motor to an EZRun 60A and Neu 1112/2D. This worked fairly well and got me up to 73 MPH. The truck felt pretty unstable at those speeds and I had to strap about 100+ grams of weight to the nose to keep it down. My next step was to go to a larger motor. Like many others, I bought the Tenbol big block mount. While the part seems nice and is very easy to install, I was unhappy with how high the motor sat and still had clearance issues with the motor I chose. At this point I decided to pursue a custom chassis. I wanted more space for a large motor and larger batteries. I also wanted a longer wheelbase for stability and to minimize wheelies.

    I wanted to do a top-notch job and decided trying to cut the chassis out with the tools I had was not going to yield the results I was looking for. I downloaded a free CAD software package and taught myself how to use it. This is the first time I have done something like this, so I took careful measurements of the stock chassis, especially all the mounting hole locations. I then started designing the new chassis in the CAD software. I knew I wanted the wheelbase to be extended 40mm, all between the motor and the rear diff. I just designed what I thought would work well. I printed the design out on paper as I went, so I could see a scale representation of how things would fit. I made multiple revisions before I was happy. The final piece was to send the CAD files off to a place to have them cut on a waterjet. I chose 1/8" 6061-T6 aluminum for the material. In hindsight, this is overkill and I could have gone a bit thinner.

    Here are the chassis plates after I received them from the waterjet. I did have to make a few small adjustments manually for things I overlooked. All the bolt holes lined up perfectly, but there were a few areas that needed additional clearance around the tranny and driveshafts. I also did all the countersinking for the bolts. I also did the front chassis "kick-up" and rear "kick-down" with an inexpensive vise metal break I bought.




    The top and bottom chassis plates are connected using M3 screws and aluminum threaded standoffs. I am using 20mm standoffs, but can run anything from 15mm to 25+mm, depending on how much battery space I need. Only a couple of the top screws are installed in these photos.






    More to come....

  2. #2
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    Next up was a motor mount. The Tenbol mount was way too high for me, especially now that I had a longer chassis and rear shock interference was not an issue. I designed this mount to be strong and as low as possible. This was not done in CAD or cut on a waterjet. This part was all manual (drill press, hacksaw, files, etc.)

    Here we have the transmission plate, motor plate, and a rear brace, all 1/8" 6061-T6 aluminum.




    Here are the parts assembled on the chassis. The rear brace was put there so that the pivoting motor plate is in a "double shear" connection. It also takes all of the load off of the transmission case that normally is presented by the weight of the motor.







    The Mini Revo rear transmission mounts are below the top of the chassis, so I had to make these little mounting tabs that bolt to the chassis and hold the rear of the transmission.




    More to come...

  3. #3
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    The next pics are the rolling chassis. The front and rear diffs bolted in with no issues. The "arms" of the bulkheads that reach towards the middle of the truck needed to have small spacers between them and the underside of the chassis. I made small blocks of aluminum to serve as mounts/spacers for the shocks. The servo dropped straight in. You can't see it in the pics, but I made a thin sheetmetal cover for the top of the rear diff. In earlier pictures, you could see the chassis had to be cut out to clear the rear ring gear. This left it exposed, so I made the thin cover to bolt to the top of the chassis to seal it up. I used standoffs to move the rear body mounts forward some. Everything else is stock Mini Revo stuff. I was able to pull the front and rear suspension/differential assemblies from my stock truck and bolt them right on to this chassis.




    The Tekno Neu 1512/2D/F mounted up.






    As you can see, there is plenty of motor space now. In fact, this chassis can accomodate a motor up to 3.3 (84mm) in length. So, I guess anything up to a Neu 1521 should bolt up to it.

  4. #4
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    Due to the extended chassis and the location of the standoffs, my battery "compartments" are 142mm long and 44mm wide. The height of the compartments is determined by the length of the standoffs used to seperate the chassis plates, in this case 20mm. I chose these batteries, ***** Rhino 3S 2550mah 40C/50C.




    I made covers that bolt onto the chassis to hold the batteries in place securely and provide a bunch of surface area to mount electronics to. They are made from thin aluminum sheetmetal and weight pretty much nothing.






    Almost done...

  5. #5
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    OK, so here are some pics that get you caught up to the current state of things. I'm using a Pro-Line Slipstream body that I did some creative trimming on. The idea is to keep it aerodynamic. Not really sure if I achieved that, but it looks cool. The suspension is "tied down" to keep the chassis low. There is still another 1/2" to 3/4" of travel left.

    With HPI Super Nitro belted slicks on Super Star wheels...






    Here are a few with some custom made foams on stock wheels...




  6. #6
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    A few more points...

    I weighed things as I went through this build. My friend's bone stock Mini E-Revo is sitting here and it weighs 2.95 pounds with 2 stock nimh battery packs. The completed truck in the pics above weighs 3.95 pounds with the big packs pictured, a Ko Propo receiver and EZRUN ESC installed. I will not be using the EZRUN, but itis all I had to get the weight. So, it is 1 pound heavier. The vast majority of that weight is the batteries and motor though. The chassis itself is only 100 grams (3.5 ounces) heavier than the stock chassis/receiver box/skidplate combo. If I were to go to thinner metal (likely 0.100") I could shave another 2 ounces or so. I'm hoping the weight won't be too much of an issue for top speed with the powerplant I am running.

    BTW, the ESC I plan to run is the Mamba Max Pro that I am waiting on. I'll be running it on 6S.

    Yes, I have Traxxas CVD's on the rear and stock plastic sliders on the front. I split one of the front drive cups and don't feel like dropping $55 on a whole set of CVDs to get that one part right now.

    The rear-center driveshaft is made from multiple stock shafts that were combined and glued. One of the joints was left free to plunge like the stock one.

  7. #7
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    Dude!! im designing a motor mount just like yours, but the other way around!!!!! ......strange......
    That was easy

    Traxxas - Futaba - Losi - Tekin

  8. #8
    RC Turnbuckle Jr. Carbonrevo33's Avatar
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    Wow, that is some serious potential speed!! Nice work!! What I don't see aerodynamic, is the front part of the body. It seems too flat, like a wall against the air. Are you considering redoing the front end a bit?

  9. #9
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    Quote Originally Posted by Carbonrevo33
    Wow, that is some serious potential speed!! Nice work!! What I don't see aerodynamic, is the front part of the body. It seems too flat, like a wall against the air. Are you considering redoing the front end a bit?
    Yeah the front is just the extra material that comes with the body out of the mold. It may not be particularly aerodynamic, but I was hoping it would minimize the airflow going under the truck. I may do a front wing instead. I just need to get the ESC so I an start experimenting. I think I have already decided to ditch the rear wing.

  10. #10
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    Quote Originally Posted by kazuaki
    Yeah the front is just the extra material that comes with the body out of the mold. It may not be particularly aerodynamic, but I was hoping it would minimize the airflow going under the truck. I may do a front wing instead. I just need to get the ESC so I an start experimenting. I think I have already decided to ditch the rear wing.
    Yea, good idea. Get a 1/10 buggy style wing, slick light, and not chunky in the front. But it's your project, do what you think is best.

  11. #11
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    Ok that is 100% kick butt right there! outstanding really.
    BUT with that kinda completely different chassis it really isnt a MERV anymore....?

  12. #12
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    Quote Originally Posted by Justanotherguy
    Ok that is 100% kick butt right there! outstanding really.
    BUT with that kinda completely different chassis it really isnt a MERV anymore....?
    I guess that depends who you ask. All of the MERV components other than the chassis are there. The layout of the chassis is not very different from stock, just longer. I don't really see it any different from using an aftermarket aluminum chassis (like GMaxx) on a 1/10 Revo or Emaxx. But everyone has their opinion...

    My question is, who cares?

  13. #13
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    Quote Originally Posted by Carbonrevo33
    Yea, good idea. Get a 1/10 buggy style wing, slick light, and not chunky in the front. But it's your project, do what you think is best.
    I'm defintely open to suggestions. I think aero will be the toughest part of this project. I will surely be trying many combinations.

  14. #14
    RC Turnbuckle Jr. Carbonrevo33's Avatar
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    It definitely depends on the person. But I just like seeing the speed, not the components that make it such a fight, just what you can do with a truck that size.

    THat's the fun part of it kazuaki. lol

  15. #15
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    that motor power someting twice that size, i have heard there is no such thing as too much power, but this defies that law...psssh, what was i thinking? I wanna see this thing do standing backflips.
    i am the most modest man, thats why im better

  16. #16
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    maybe 3bckflps standing........oohhh......aaahhhhh

  17. #17
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    Quote Originally Posted by kazuaki
    Yeah the front is just the extra material that comes with the body out of the mold. It may not be particularly aerodynamic, but I was hoping it would minimize the airflow going under the truck.
    Like I said previously, I love your design & build

    I think the elongated body front is very aerodynamic & will train the airflow but a small splitter at the front will make forward airflow more predictable

    I see there are 4 basic elements to an open wheel design...1st is the splitter, 2nd is the body, 3 is the rear wing & 4 is wheels



    You can adjust everything except the wheels fairly easily & this is the splitter function...



    but in your case I think something more exaggerated in terms of length & perhaps even reducing the high pressure area by smoothing the splitter to body area - which increases the downforce...& then if you need to, you can reduce this effect by reducing the size of the splitter. I hope that makes sense?
    Last edited by PBO; 10-02-2009 at 09:36 PM.

  18. #18
    RC Turnbuckle Jr. Carbonrevo33's Avatar
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    Wow, very nice man!!!! That should help alot with the design.

  19. #19
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    Makes sense to me. I think it would be very difficult to build a splitter that is smoothed into the body. So, the front wing would probably be the best bet, as it seems it would have the same effect. Something like a nearly flat wing with a small lip at the rear that just touches the body.

  20. #20
    RC Turnbuckle Jr. Carbonrevo33's Avatar
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    Hey, it's not in this forum(section), but to show what you could do:

    http://monster.traxxas.com/showthread.php?t=493316

    They designed it so it has more downforce, perhaps you can make it and shoegoo, or a better compound and mount it to the front of the body like you have now.

  21. #21
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    "Something like a nearly flat wing with a small lip at the rear that just touches the body."



    Exactly!

  22. #22
    RC Turnbuckle Jr. Carbonrevo33's Avatar
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    Hey, Kaz, do you have the dimensions of your new build?

  23. #23
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    Quote Originally Posted by Carbonrevo33
    Hey, Kaz, do you have the dimensions of your new build?
    The chassis is 40mm longer than stock. Is that what you are asking?

  24. #24
    RC Turnbuckle Jr. Carbonrevo33's Avatar
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    Well, if that's the only thing that changed dimension-wise, then yea, that's what i was asking.

  25. #25
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    I love this, an awesome project that is nothing less then awesome. Did I say awesome to many times. I hope your speeds can reach up to 100MPH. If you do I NEED to see video of this.

    My Revo project is an all stock top speed of 62 MPH. Well all stock unless you don't count CVD's that are Traxxas.
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  26. #26
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    Man, that is really nice. i would add the front spliter like PBO said
    The biggest thing i've broken: My wallet.

  27. #27
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    Quote Originally Posted by Carbonrevo33
    Well, if that's the only thing that changed dimension-wise, then yea, that's what i was asking.
    Pretty much, because the width is determined by the a-arms and bulkheads, which are stock.

  28. #28
    RC Turnbuckle Jr. Carbonrevo33's Avatar
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    Yea, thought so. That's a good example of how it depends on if it's really stock or not. It's only a 4cm diff.

  29. #29
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    Quote Originally Posted by Laxman101
    Man, that is really nice. i would add the front spliter like PBO said
    Working on it already...

  30. #30
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    That is some serious custom work, man I wish I had the time and money to do a project like this, you and LiqrSicc have the most amazing revos I have seen!!!!!
    MMP-NEU 1112 1.5D 4S MERBE
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  31. #31
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    Man, this is awesome! Perfect! You did a terrific work on that chassis .
    Could you please upload somewhere the pics in hi-res (I presume you have them )? I'd like to appreciate every detail of your work . Thanks.
    merv+lipo3s2p1500mAh20/30C=fun

  32. #32
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    that is and awsome chassis. you are really putting some thought into it arent you.
    i bet my Quad could out RIP your Quad!!

  33. #33
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    What would you charge to create a kit?

  34. #34
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    another thought. why use bigger batteries if your only making a couple speed runs you wouldnt need big beefy 2300 batts. then if you get smaller batts that would reduse the weight too making it even faster. and what kinda sppeds are you expecting to hit and what motor esc combo will you be useing? then you should get a slick lambo body.
    i bet my Quad could out RIP your Quad!!

  35. #35
    RC Turnbuckle Jr. Carbonrevo33's Avatar
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    What's your speed goal? Are you aiming for something? Perhaps over 100mph? I guess that's what Chris is asking.

  36. #36
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    Quote Originally Posted by Chris York
    another thought. why use bigger batteries if your only making a couple speed runs you wouldnt need big beefy 2300 batts. then if you get smaller batts that would reduse the weight too making it even faster. and what kinda sppeds are you expecting to hit and what motor esc combo will you be useing? then you should get a slick lambo body.
    Larger batteries are more able to handle high current demands because the current output is the "C" rating multiplied by the capacity. These batteries are rated at 102 amps continuous (40C x 2.55 amp hours). As an example, the popular 1550mah Rhino 3S packs are rated at 46.5 amps continuous (30C x 1.55 amp hours). With a big motor that wants a lot of power, a larger battery will perform better.

    I will initially be using the motor you see in the build. For the ESC, I will be running either the Mamba Max Pro that I have pre-ordered or the MMM that Castle is repairing now.

  37. #37
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    Quote Originally Posted by Carbonrevo33
    What's your speed goal? Are you aiming for something? Perhaps over 100mph? I guess that's what Chris is asking.
    My ultimate goal will be to break 100 mph, but I'm going to start by aiming for 90 mph and see how it goes. Anybody that has done speed runs knows that there are a ton of variables that come into play and it is NEVER as easy as you think it will be.

  38. #38
    RC Turnbuckle Jr. Carbonrevo33's Avatar
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    Well doing the top speed project now will help. Many people have tried and failed so far, with the stock one, but they know what to do to improve it. You get their notes on what they need to improve on and you can see that revo going down the road at 90-100+mph.

  39. #39
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    One of the first obstacle once I get the ESC is finding the right road and having enough radio range. The longer the run up I can get, the more control I can maintain. But I have had glitching issues in the past once I get beyond a certain point. All this with the new Ko Propo EX5-UR, that is supposed to be a very good radio. It has nice features, but the range has not been that impressive.

  40. #40
    RC Turnbuckle Jr. Carbonrevo33's Avatar
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    And that is 2.4ghz right? Sorry, I don't know alot about KO Propo. I love my DX3.0, I can go to the end of the street where my slash is a dot, and not have troubles. I love it!

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