DT-03T Aqroshot

[Effigy3]

Nobbi1977 did an excellent build thread on the DT-03 Fighter Buggy here. This should be a very similar build. Hopefully there'll be enough difference to make the thread worthwhile. With that in mind I thought I'd do my own build thread on the DT-03T Aqroshot stadium truck variant which I'm building as a surprise Christmas gift for a buddy of mine. He's brand new to the sport and has never driven a hobby grade R/C before. I expect that this truck will see a lot of backyard, driveway/street, play park duty with a reasonable possibility of some beach action. So those are the parameters for this build.

I typically shy away from box art because to me, one of the beautiful things about kit builds, is that you can personalize them. One of his favorite colors is "hunter green" so I will be doing a base color of Tamiya PS-22 Racing Green with a Tamiya PS-01 White paint drip scheme on the nose. I think the white on the nose will break up the green, providing some visual contrast so it's easier to see which end is front at a distance, and it will tie the white rims in with the overall color scheme of the truck.

The build itself will stay mostly stock. The key upgrades will include rubber sealed bearings from Fast Eddy. I'll use metal shielded bearings in the gearbox though. A Tamiya 17T steel pinion gear because we all know the stock alloy jobbers Tamiya includes are made of cheese. I also will be configuring the TBLE-02S speed control to brushless mode and installing a Leopard 21.5T motor. Since the ESC doesn't have a built-in low voltage cutoff a battery level alarm will be included with the unused 3000 mAh 20C LiPo battery and wall wart charger that came with my sons Losi XXX-SCT kit.

I'll be using a Flysky FS-GT2B (scroll down) Tx and Rx. I plan to couple those electronics with a Futaba S3003 "standard" servo. I am concerned that it might not be torquey enough to turn the Proline Dirt Hawg I tires which will be the final hop-up used in this build. It has 8 oz-in less torque than the standard servos I see used in many RTR stadium trucks on the market.

All the parts are as yet inbound. I plan on painting the body first so there is plenty of time to make suggestions.

[Nobbi1977]

Sounds like an interesting build. I think building straight and stock is the best way to go so your friend can hop it up if he gets addicted.

[super gripper]

My DT03T Aqroshot......

http://www.tamiyaclub.com/forum/index.php?showtopic=77779#entry603742

​

[volvotech]

Nobbi's build thread inspired me to purchase a DT03, I've never looked back. Great value and fantastic car to bash around with. I'll be following this thread, I'm curious to see the differences between the buggy and truck versions with some detail.

[Rich1978]

Do u think a Blitzer Beetle shell would go on this chassis ok?

And what about BB tyres, what brushed motor could you go down to?

[Effigy3]

I did see your truck Super Gripper. I love that checker pattern. Looks good.

Volvotech, this is good news. I have no idea how much abuse this thing is going to get but I suspect it'll be a bit so hearing how durable it is, that's music to my ears.

Rich1978, Someone else will have to answer this because I know nothing about a Blitzer Beetle.

[Effigy3]

The kit arrived today along with the primary colors. The box is a lot smaller than I expected. Certainly smaller than my Frog or Grasshopper box. I don't know why I was expecting larger. Not that it really matters.

Here are all the pieces laid out that came in the kit:

The body. If you were wondering where the little rear fin is, it's actually molded into this one piece and is cut out from the rear section of the mold under the bumper.

The mold is stamped 2009 so this body must've come from a previous model that I'm not familiar with. There are mounting points in the recessed bit on the hood so if anyone can tell me what is "supposed" to go there it would satisfy my curiosity.

And I have it cut out. I'll mask it up this week and paint it this weekend assuming no rain. (Crosses fingers!)

[super gripper]

It is a Vajra body.

http://www.stellamodels.com.hk/58497-vajra-wbonus-item-minor-body-creases-p-5762.html

​

[GregM]

Yep. Vajra, and also used before on the brushless Super Levant.

[Effigy3]

The mold is stamped 2009 so this body must've come from a previous model that I'm not familiar with. There are mounting points in the recessed bit on the hood so if anyone can tell me what is "supposed" to go there it would satisfy my curiosity.

After looking at the Vajra and Super Levant, I think these dimples are locator marks for alternative body mount points for those other vehicles. Which means this trucks hood has a recess on purpose. A reverse hood bulge is an odd looking thing to my eyes.

[Effigy3]

I got a bit more work done last night. I masked up the back end but have to figure out what kind of paper I want to use to block off the middle and front end. It seems a waste to use all my Tamiya masking tape on that. UPS tracking showed that the Dirt Hawgs were on the truck for delivery at 6 am. They arrived on my stoop at 10 pm. That's a lot of driving about on a truck considering it takes all of 20 minutes to transverse the town I live in. I was too curious about how the tires would look mounted so I did up the front rims before bed.

The tread pattern is perfect for what I'm aiming for. An all purpose truck that is equally at home on pavement as it is in the dirt or grass. Here they are compared to the decidedly smooth surface biased stock tires:

They have a slightly larger outer diameter than the stock tires but not nearly as much as I was expecting. The Dirt Hawg II's shown in the image posted by Thommo here look taller but that might just be an illusion created by the more aggressive "luggy" tread pattern they have. The overall effect of the mounted Dirt Hawg I tires is that of a low-profile, off road tire rather than a proper off road tire with tall sidewalls. In the end I think these will actually be the better all-rounder which makes them perfect for this build.

Of course if my buddy decides he wants dedicated street tires so as to not prematurely bald the off roaders he can always buy a set of rims and mount the stock ones up himself.

[Kevin_Mc]

i know what i now want for Xmas!

[Effigy3]

Does anyone have an opinion regarding this motor for this build? Atomik Red 550 2650kv 7.5T Sensored Brushless Motor

I keep trying to talk myself into the 21.5T motor but I'm afraid it's going to be too slow. Sure slow is good at first but how quickly will he out grow it and want faster? I have the 21.5T already, but I have this one too. In fact, I have two because I just couldn't pass up the sale price! I know the turn count seems really low, but it's a 550 motor and is only 2650K so is more than reasonable but would the TBLE-02S handle it? It's technically below the turn count the ESC is rated for. Then again, I do have the cooling fan for the ESC so maybe that would allow this motor to work with the ESC.

So, what does the collective TC wisdom say? I must use the TBLE-02S (with or without the cooling fan) so the only real options here are the Leopard 540 1820K 21.5T motor or this Atomik.

[Nobbi1977]

I think amps more than turns is a measure to go by.

[Effigy3]

I think amps more than turns is a measure to go by.

Agreed.

The Tamiya USA site states TBLE-02S ESC has a maximum continuous amperage capacity of 60A.

The Atomik Red motor has a maximum current draw of 50A.

So: 50 < 60 = I should be good to go using the Atomik motor with the TBLE-02S ESC. Yes?

[XV Pilot]

You should be fine regarding the ESC, but you might struggle with the pinion. 540-size motors commonly used in 1/10 scale RCs use a 3.2mm shaft. The 550-size Atomik has a 5mm shaft more commonly seen in 1/8 scale vehicles. Finding a pinion to fit the shaft and the DT gearbox might be a challenge.

[Effigy3]

You should be fine regarding the ESC, but you might struggle with the pinion. 540-size motors commonly used in 1/10 scale RCs use a 3.2mm shaft. The 550-size Atomik has a 5mm shaft more commonly seen in 1/8 scale vehicles. Finding a pinion to fit the shaft and the DT gearbox might be a challenge.

Ooooh... Nice catch on that one. Yeah, that could be an issue and quite frankly not one worth mucking about with. It looks like I'll be sticking with Plan A then. 21.5T Leopard motor here we come!

[Effigy3]

Or, maybe not... When I got home I checked in my parts box and found a Robinson Racing 8718 Extra Hard 18T 5mm .8 mod pinion. I checked the outer diameter of it against the stock Tamiya 17T alloy and it's VERY close. So, given that the motor mount will allow for 17 or 19 tooth pinions, I've ordered an 8717 pinion. I think it will work just fine with the Atomik motor. It should arrive on Sunday which is plenty of time. I probably won't be able to build the chassis until next weekend. This weekend will be painting the body. I could test the fit in my sons DT-02 though...

[Effigy3]

I started on the chassis this morning because it was too cold outside to paint. The manual instructs you to apply foam tape to the inside of the battery box and then screw the two halves of the chassis together with 3 screws. While the manual says to double up the tape on the inside, I had to remove the 2nd layer in order for the hard pack LiPo to fit. With a single layer of foam tape the LiPo fit perfectly! The 2nd layer maybe necessary if you're going to use NiMh packs.

(Edit: I tested it and yes, if you are going to use NiMh battery packs the 2nd layer of tape is required for the battery to fit snugly. If you would like to use both battery types for some reason, I suggest building the truck with only 1 layer of tape and adding a layer of tape to the end of the NiMh battery to make up the difference.)

The front stays are affixed to the chassis with 4 screws. One of the screws is a 15mm where the other 3 are 12mm. I don't know why this is the case but I think it is a detail that is easily missed.

The next step is setting up the electronics. Namely centering the steering servo but I took this opportunity to configure the ESC as well. I haven't swapped out the power connector on the ESC yet. Luckily I still have one battery with a Tamiya style plug on it.

I'm using a Futaba S3003 standard servo. It's a decent enough servo but it is decidedly a basic servo. A high torque - metal gear unit would be best. That would make for a great future hop-up for him.

Once the servo was centered, I installed the ball connectors onto the servo saver. I also opted to use 4 screws to hold the servo in its mount rather than the 2 called for in the manual. Luckily I had plenty of spares in my box.

Next up are the steering rods. They are metal shaft with ball cup ends. They're also equal length which should really make for the nicest direct servo steering of any model I've ever built!

Then, to finish the the steering we mount the servo into the nose of the chassis. It goes in upside down. There is an easy access hole under the chassis so the servo saver can be unscrewed thus allowing the servo to be removed without completely disassembling the entire steering setup. I really appreciate this design because it reduces the amount of on/off cycles the ball cups must endure, thus extending their life span. That said, I'm not keen on the big hole in the front of the underside of the chassis. I'm going to have to find something to cover that hole up with. A nice piece of adhesive carbon fiber would be perfect. I'll have to see what I can come up with.

(Edit: Turns out I didn't really have anything that would work other than duct tape so that's what I used. My wife has all these fancy paper punches for scrap-booking so an oval shaped one worked great to cut a nice piece of blue duct tape tape. Once it was on, TBH I think it'll actually work pretty well.)

[super gripper]

you will need to add weight to the front of your DT03 as it is too light or it will handle like a bag of pants

[Effigy3]

you will need to add weight to the front of your DT03 as it is too light or it will handle like a bag of pants

Why is that?

[Effigy3]

The next step is to install the lower suspension arms. They connect using a u-shaped pin which is held in place by the front bumper.

This is where I made my mistake. One that I wouldn't catch until much later. If you notice in the image below, I used the wrong lower arm on the right. That's the arm for the rear suspension.

It's secured to the chassis with 4 counter sunk screws.

The front axles are extra long in order to be able to mount the wide front tires. Everything is held together with screw pins. I hope that they don't have the same bad habit of backing out like they do on the DT-02.

[Effigy3]

Building the differential is up next. I used Tamiya grease on the large bevel gear.

I used Tamiya differential putty on the small bevel gears to create a limited slip effect.

Now that I'm posting these pics, I'm thinking that I shouldn't have greased the large bevel gear if I'm going to use the diff putty. Whoops!

The counter gear and differential installed in gear box.

The gear box is buttoned up and this is when I realized my mistake with the lower suspension arms.

Oh hey, look at this rear suspension arm on the front. Seems a little large-ish so I suppose I ought to swap it out.

Upper suspension arms, the correct lower rear suspension arms and the outdrives are now installed.

Dogbones and rear axels installed. Everything is screwpins.

This is what the completed rear assembly looks like. That's a lot of motor wires... Wow! Novak says don't cut them because the ends are pre-tinned and if I cut the wires the new bare wire won't take solder. I'm going to have to put that to the test someday.

[super gripper]

Once you have built the car you will instantly notice the centre of balance is so far rearward it is ridiculous. I have jammed 45 grams of lead in the front of mine just to get some sort of front end bite.

[Nobbi1977]

Grease and putty will mix it to paste that will be like thick sticky grease. Should have a limited slip effect but do not volunteer to clean it out when the effect starts to ware off