Sunday 3 August 2014

Tamiya DT03 NEO FROG FIGHTER BUGGY

TAMIYA DT-03 NEO FROG  

if i am honest, the release of the dt03 was a non event for me , i took a quick glimpse at the pics then promptly forgot about it , getting old and ever busier kinda sucks ! 
however , i was on line at work the other day and got an email from a UK hobby shop with their latest offers and the neo fighter jumped out at me .
This started a search in all the usual places , tamiya blog , thercracer , tamiyaclub  , all of which proved quite informative and confusing at the same time , i am still not sure what actually comes with the kit, some say oil dampers , some say friction dampers , even tamiya images have differing info . One highlight of the kit is the new brushed/brushless cross compatible ESC the TBLE-02s , this could well be a genius move from Tamiya , consider the beginner who has bought a dt03 , if they should want to go racing in a stock class with brushed hand out motors the esc doesnt need to be replaced , then it can be used with a brushless motor should they want to move up to a controlled brushless class  , having said that i am still not sure if the buggy itself will be up to it.
according to the review on the rc racer blog from a chap i have conversed with and i know and trust that he has tested the dt03 to beyond its limits under race conditions that the buggy is well up to control class club racing.

i may yet paint it in the neo fighter colours but i really love the frog livery ,


it arrived from Germany , very quickly too ! 

i am delighted to report that, as can be seen from the stickers on the box , it does indeed come with all the bonus parts that i feared may only be in the fhe first run .

it went together with almost no issues , one gripe was that the shocks are really awkward to remove from the front of the buggy  due to the rear mounted position, i overcame this by fitting some blue 4.8 pillow ball nuts i had ,thankfully the kit cva dampers still retain the ball cup type ends, 












i went for my own take on the original frog livery , the pink is mixed from fastcolor raspberry pearl and white ,  if you have or plan to get a neo fighter to race or run on a track then buy a pack of tamiya ball studs while you are at it , removing the small amount of slop from the shock mounts really helps the car in tight track sections , unimportant if you are just bashing around . i cant understand why tamiya didnt include them to mount the dampers as they have ball socket ends that are a poor fit on the stock step screws. 

Given the low screw count and the intended wet grass track use i have replaced most of the hardware with A4 'marine grade' stainless steel button head allen type screws , i will also fit some stainless steel hinge pins and titanium turnbuckles , i also plan to fit a small cooling fan over the ESC as there isnt much airflow under that snug fitting body shell , as it will be used in the wet a lot i dont want to cut the body for cooling . 
i will be running LiFePO4 6.6v 4200mAh pack which the esc is suited to , this too should keep the temps down a bit , i also expect it to run much cooler when in brushless mode so i will try that before fitting a fan . the install is really neat , i love the simple RX cover too ,


the hop up selection that was announced at the same time as the buggy release are all well considered and hint at what tamiya intend the buggy for , racing in their fighter cup class , 
i would like to try and lighten up the unsuspended  mass , uprights , outboard hinge pins , and adjustable upper arms with titanium turnbuckles , alloy wheel nuts and perhaps hollow front axles 
would all help to hone the already good handling buggy , perhaps we will see a slipper and sealed gear diff at some point , 

so i just ran the dt03 with the tamiya esc and 13.5t motor and LiFe battery using the same tyres i use on the dt02 , the 03 gets round the same track 2 seconds a lap quicker than the 02 with lipo ,, despite the fact that the dt03 is a lightly reheated dt02 it is a quicker car that suits uk grass track so well , its as quick as my ansmann x2 pro buggy ! 
on tracks with lots of jumps the dt03 is lacking a touch , the front end is now far more efficient than the rear so the rear end kicks up much like the dt02 , i will try a set of dt02 tuning springs to see if the 'kick ' is from the rear end slapping the ground from being under sprung , need to be careful i dont upset the nimble cornering it has in stock form , i would love to see tamiya do a new gearbox moulding with squat adjustment for the lower arms  ( wishful thinking ) .


you may notice the rather neat electronics instal, Tamiya should applauded for finally including a receiver cover and some simple cable management , i did drill two 3mm holes to cable tie the battery socket to the chassis for easy connection and disconnection ,


i was planning to lavish all the hop up parts on the frog , to be honest it just doesnt need them , if you get the kit with oil shocks , brushless esc and torque tuned motor the oly thing you have to add is a set of ball races which cost around £8 from rcbearings.co.uk . build the shocks as per instructions and simply use front and rear ride height adjustment and front toe in/out to change the handling . even the plastic drive shafts are superb , the funny thing is that the drive shafts collect less grass than the far slimmer steel UJ shafts do! go figure .

the oil filled damper kit is a welcome addition to such a cheap kit , however i found the rear dampers to be very sticky (stiction) , i soaked the 'O'rings , i added a small amount of  AE slime but still they refused to operate smoothly, 
i have had shocks from tamiya before that also had the black coating on the shock shafts , they were fine and worked straight away without issue , the dt03 rear damper shaft also has the black coating , as this was the only variable i took them out and polished them with some solvol autosol , immediately after reassembly they were superb, smooth and consistent , polish the rear shafts for best results .

in the damper assembly manual it tells you to fit 3x6 spacer X3 to the rear shock shafts , leave them off the dampers , with these fitted my dt03 kept grip rolling when the damper bottomed out , when i took them off it stays on 4 wheels and has more consistent grip , tamiya spec the spacers to prevent drive line binding , however ,in practice i never had any issue with binding with the spacers removed, the motor didnt get any hotter and the drive line shows no wear , its one of those parts that makes sense on the workbench but in practice just causes a new set of issues , the grip roll occurs when the shock absorber bottoms out and causes a huge spike in downforce on the rear tyre , fast cornering demands a controlled ,balanced,amount of lateral grip and slip , effectively the car is always drifting in high speed turns ,, throw a sudden spike of grip in the mix and the tyre and rim dig in ,then, the car has no option but to flip on its roof  ,  

a few hop ups arrived today ,
 it says to glue the edges of the carbon damper stays , i really didnt want to as the parts are well machined and a usually get CA everywhere , however , Tamiya have used a serrated edge finishing process , this gives the edges a ridged effect and allows the glue to flow evenly along the edges , some use a cotton bud or similar but i prefer to use medium CA and a thin applicator nozzle and slowly work a drip down the edge while holding the part in a way that uses gravity  to run the glue along the edge , well done Tamiya for taking such care when producing these hop up parts , every thing is the usual Tamiya quality (very good !) yet the prices are a little lower than they usually do , we need a specific DT-03 spring set though as the trf buggy springs are aimed more at the 4wd buggies .
the servo mount (hi torque saver already fitted) which i thought was a nice bit of bling also serves to stiffen the chassis front end ,  there is a noted reduction of the front end hooking and sending the car into oversteer , more poised on corner entry and mid point which encourages me to get on the power a bit earlier ,.
the adjustable upper arm kit is nice , my mini pins are worn out and the spikes are bit too much for dry grass , with the arms wound out to give some positive camber to dial out a bit of grip the car becomes drivable again  , the anti roll bars have helped to inhibit the cars tendency to roll through its rear end travel and grip roll , 

so far i have found the tamiya hop ups to be beneficial in making the car more consistently tuneable if the weather changes throughout a day at an outdoor grass track , i get the feeling that this car will be good on worn tracks that are a bit drifty , the chassis generates loads of grip .












i was rather disappointed with the fit of the front anti roll bar (sway bar) , the channel that the bar rotates in is about 3.5mm-4mm , the bar is about 1.1mm , this gives a very sloppy fit and render's the roll bar useless as it twists rather rotates , to cure this small issue i fitted two 14mm lengths of the kit antenna tube ,one bit on either side of the blue centering slug,, the tube is quite rigid and wont slide on the bar as is, but ,,with a tiny amount of heat from a cigarette lighter or even some hot water is enough to soften it and it slips on easily, once cooled it goes rigid again and is a good fit in the channel and reduces all the wobbly slop,

you may have also noticed that i have flipped the front upper arms so they are now in front of the bulkhead/shock tower , i did this as i found in the past that contact with other cars or objects can pop the the links off when they pop off backwards , they stay put when on the front , not to mention the extra protection they give to the front dampers , if you opt to do this you will have to add a 3mm spacer behind the ball nut that mounts the upper arm (turnbuckle) or the arm and spring will rub , 

the kit geared diff is in my opinion fine , a ball diff can help on some tracks where front grip is lacking , a tight ball diff increases turning and off power turn in ,, but for where i run they are not so good , they wear quickly and constantly need rebuilding , tamiya's simple geared diffs are strong and reliable , if needed you can slow the action using differing thickness/tackiness of grease used inside the diff,  ,  

springs!
after a few runs with a 10.5t motor using the kit springs and then a few with the 3racing springs i have found the rear kit ones are too soft and the 3 racing ones are way too hard (impossible to get any droop at all)  , i dug through my parts bin and found some yeah racing silver (soft) springs that are firmer than the kit springs , in tamiya terms i would say they are pretty close to yellow rated Tamiya trf springs , up front i found some very soft mardave cobra front springs which i compensated for with 40wt oil  and 2, 0.8mm hole ,pistons , this gives increased compression damping which helps keep the nose up when launching off the jumps , but maintains good corner turn in , it can get a bit pushy on power for some  drivers , i will of course get some try buggy springs and report my findings , i also still have to get it on a dirt track to see how well it works , 

i managed to take the esc into thermal shutdown with a 10.5 motor and 19t pinion , will try again with a 17t pinion and wind the timing down to around 20deg to give a but more low rev punch but ease off current draw at higher revs . 
after much trial i have found that the TBLE-02's esc cannot handle a 10.5 motor off road , even at the recommended gearing in the esc manual , i have gone back to 13.5 with 19t pinion , i have though advanced the timing on the motor to 42 degrees (30 being the mid point , 15 the minimum and 45 the maximum ) only do this if the esc and motor are well below max thermal tolerance , with 13.5 and 19t the motor barely gets warm and the esc likewise , with the advanced timing it still doesnt get hot so its well within limits and can shift on the straights while being reserved enough under aggressive acceleration to curtail the tendency for the front wheels to lift a bit.

 more soon



2 comments:

  1. What kind of wheels and tires (black 5 spoke) are in the pictures after the motor? I just got a DT-03 and am going to building it with a 13.5t Trackstar motor. I like what you did with yours.

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  2. Hi,

    Which Tamiya ball studs did you use? Is there a Tamiya part number? I'd like to remove some of that slop.

    Thanks

    Matt

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