So for a while I’ve been thinking about getting an RC Helicopter. In fact, its been a long while, but the thought pattern always ended up the same, I’m gonna crash it. For some reason, this time was different, and I ended up purchasing an E-flite Blade 400.
While in Japan I picked up an F-104 Pro. I’ve ummed and ahhhhhed about the purchase for ages, but once you’re standing in the shop on the other side of the world holding the box there isn’t much of a choice. So back in Australia it was time to build it. Of all the cars I’ve built, this one was the easiest, which isn’t a bad thing.
I’ve build it stock except for the following:
For the electronics I ended up with
For the first time since November last year, Dan and I finally got to take our cars out together. For one reason or another, 1 car has always been broken or not working quite right for the last 6 months, so there was some excitement in finally getting the cars out together.
We built a new rear diff for Dan’s car in the morning, so it would be running the metal diff like mine. When Dan took his car apart, his pulley was also starting to melt, with oblong holes for the diff balls. With everything tighened up and the sun shining we headed out.
Read on….»
The parts arrived during last week (or was it the end of the week before) and the durga is finally repaired. In the end i purchased the parts for the rear diff and the aluminum suspension mounts. I didn’t get the front uni’s for the db01, but now wish i had.
The rear diff has been rebuilt, using the TRF501X diff joints, and it feels smoother, stronger and all round better. Using the numerous howto’s / guides / forum posts I have now adjusted the diff to a “nice” feel. Reading these posts is something i should have done before putting the brushless in, but thats life. The manual gives you the basic idea of how tight to tighten the diff, but what is tight. The advise differs greatly, from tighten until you can’t tighten anymore (which i still don’t know how to judge) and back off a bit, to just follow the manual and tighten until you can’t turn the pulley with the diff joints held in place. In the end, I followed the advise of tighten until the diff feels tightened which i figured, was when the screw went from easy to turn to hard to turn. Then lock the slipper (basically tighten until the slipper spring is fully compressed) and hold the rear wheels. Try to turn the spur gear with your thumb, if you can then you need to tighten it further, in 1/8 turns until you can’t. Then repeat at the front. For the slipper, tighten so that it slips for the first few feet of acceleration. I started with it at about 5mm. I of course don’t claim that this is the right method, or that it will work and not break your diff, but this is what i did, and it seemed to work.
So with the diff rebuilt I went off to the Knox Offroad RC Track to have a look and a drive. This was actually the first time that i had taken the Durga with the Mamba Max in it to an actual track instead of the famous figure 8 BMX track in North Melbourne (and by famous i mean Dan and i know what i’m talking about). Arriving at the track at 9am, i was suprised to see a few people already there, it was a public holiday afterall, why aren’t u sleeping in. Oh well, may as well show them how n00bish i am. I placed the car on the track and accelerated. It lacked punch and made a whirring sound. This i now know means that the slipper is slipping, but it was slipping too much so I tightened it up and the durga came to life. Driving it on the track turned out to be a lot harder then i expected, the durga jumped around all over the place and took alot of getting used to. I really couldn’t use the power thru most of the course as its tight, but it flew down the straight and took the jumps very nicely. I admit that this is the first car i’ve had that can go off jumps, but it seemed like the durga is nicely weighted over the jumps. It takes off nice and straight and lands without slap. There was a DF-03 and a 2wd Tamiya buggy there and the durga seemed much nicer over the jumps. The others seemed to be very front heavy. And in case you were wondering, the durga easily cleared the 3 bump jumps below in the pictures, on the first attempt landing in the next corner. After that I took it alot easier over that one 
Last thing to note with the durga was the new tires that were on it. I ended up buying a cheap set of tires for the car. They were rubbish. the rubber been so hard it was last forever, but also not able to grip to the dirt. I think that made the whole exercise that little bit harder, may have to rethink the situation, cause the kit tires were much nicer (and don’t really want to spend massive amounts on high grip, quick wear alternatives).
After Knox i went up to templestowe to run the mini. I haven’t driven the mini for ages, and I don’t believe i have driven the Hobbywing brushless system at templestowe. For today, i popped on some new tires, Team Powers 36′s, and the car was a delight to drive. The hobbywing was smooth, and responsive and onlookers were even impressed with the little cars speed. And the tires, where the durga’s were a disappointment, these ones were fantastic! The extra grip they provided over the kit ones was amazing. This grip was so good it begun to cause me problems. I was able to carry so much more speed into the corners that I was beginning to roll over through the faster ones! They also still look like new after a 40 minute run. I give both products 2 thumbs up.
Today really reminded me how much fun it is to drive on actual tracks. To have a purpose and course forces you to drive the cars, not just go flat out in a straight line, spin, and go back the other way. Great fun.
Check out the knox track and the new tires on the mini below (and i am hoping that apple will give me some money for some nice ad placement):
At the Knox Offroad RC track, while driving the durga…….
Little kid 1: you ask him
Little kid 2: no you ask him
Little kid 1: no you ask
Little kid 2 to me: Excuse me, but can we have a drive of your car
* Thoughts of introducing a new kid to the sport, giving them the rush of a powerful rc car, the joy and excitement for them, and the fear of a parent as they think of how much it will cost them. Then the thought of trees, poles and clubhouses and my newly fixed car *
Me: no
Been a novice means you are always learning. Some lessons are easy, oh my, the car turns to the right when i turn the wheel to the right, and some are a little harder and you don’t see them coming.
The lesson learnt above falls into the latter. The trained RC ear would have heard there was a problem with their DB01, and pulled over, taking it apart and working out the issue. My ear heard no problem and continued on, the first sign of trouble been a lack of rear drive as my 4 wheel drive turned into 2.
Eventually got around to taking the diff apart, and was shocked to find out what had happened. The first clue was when diff balls fell out of the drivetrain when I took the covers off. I thought that rather odd, so continued on, thinking the diff had become loose. I took the diff out, and noticed the pulley was moving very freely.
I removed the diff screw and thought something along the lines of “holy shit-cakes batman”. I’d melted the diff, completely destroying the pulley and melting the diff rings into the diff ring holders. It was a mess. Luckily it was only the rear, the front diff looked very nice.
I loaded up the trusty internet and started to search for people in similar situations. It didn’t take long. Seems that if i had have researched a little better, i would have known that this same situation was happening to DB-01 users all over the world. The thing we all had in common was High Powered Brushless setups. Although the drive train was designed and built to handle them, the diff joints were not. With it been a combination of metal and plastic, and the use of glue to hold the diff rings on it just wasn’t going to cut it. This user on the oople.com forum sums up what happened best:
“The diff plates are glued in place on the DB-01, which is great when you have little load on them, but when you put a 6.5 in it, the loading on the rear diff is significantly higher, so the glue ends up cracking, the plates then start to slip, everything heats up, and then you got a molten mass in the rear pulley.”
- http://www.oople.com/forums/showpost.php?p=214596&postcount=7
So the path forward is to get the TRF501X diff joints (part #51286) which are up to the task, and a direct drop in replacement. So they have been ordered and are been flown to this wonderful land as we speak. They are a little more pricey then the standard plastic DB01 replacement, but its only going to happen again so I may as well fix it for good.
I’m also going to finish off the car with the “essential” hopups. Aluminium suspension mounts and front uni’s will hopefully give me an edge against the competition (you know who you are) and hopefully a more reliable car.
Another lesson learned.
Its been a while since the last post, but that doesn’t mean there hasn’t been lots of practice. All the cars have been out, and all in all its been a blast. But as with all stories, there’s always a down side, and mine is the cars have copped some damage. Probably the worst has been the durga, and its all been to do with the speed.
One summer day (hasn’t been many) I took the durga out with Michaela’s brother Dave and we had a bit of drive around the local netball courts. Looking at them, I think there is 4 courts, so thats a very large flat area with 8 poles dispersed around the place. So the TT-01 and the Durga went out (we were to have his nitro going as well, but unfortunately that wasn’t to be), and as Dave hadn’t seen the durga in action yet, it was a good way to start going in straight lines to show some of its new found speed. Take it easy i thought, don’t want to damage it, and I’d say i did quiet well for a while. Not really sure what happened next, but i was going in a straight line, then it turned, or bounced or something, and then it was going sideways and hit a netball pole. There was silence. The result is below. Tough little car, but thats the last time it goes to the netball court. Day continued with me driving the M03, and unfortunately the same pole also claimed a suspension arm off the tt-01. Oh well, it was good fun.
Other then that, I had a bit of a practice at Templestowe (TFTR) track again, and that was nice. It was weird driving a track again, as for the last few weeks i have been driving very open areas. Suddenly it was tighter, but you have a purpose, not just spinning the car around and driving as fast as you can in a straight line. I was hitting the curbs a fair bit, but after a while i think i was back in the “groove”. It was good fun and I have to say the track is looking fantastic after they finished it, people should definately go and have a look.
Here’s some pictures of the durga and tt-01 after the netball session:
*This story is here for a bit of a laugh. It wasn’t / isn’t funny, but you have to laugh otherwise you’d cry*
As mentioned in earlier posts I decided to get a Mamba Max combo for the Durga. At the time of the decision (which was August) I decided to go with the same company that Dan had ordered his off. As Dan also had a discount coupon, I took advantage of that and he placed the order.
From about this point on, it started to go downhill. Dan’s order was taking a long time to arrive after been shipped. There was no real word from the company as to where it was, and eventually they fessed up and admitted that they had drop shipped it and multiple shipments were missing. This, was disappointing, but another was to be shipped. Problem was, there was a shortage on Mamba Max Combos. Many weeks of we’ll have them soon, and this week i promise, we were no closer to having anything. Eventually, there did come into stock, and we were told they would ship the two motors together, with deans connectors and the battery Dan ordered.
One morning, the email finally comes in, shipped. We ask for a tracking number, and about 2 weeks later we get it. Tracking number reveals it was only shipped a couple of days before. This guy is starting to give us the shits, but its ok, cause it will arrive soon. It is tracked across the globe and arrives 8 long days later. The package is opened, and only one motor. Bugger.
An email exchange back and forth and a couple of weeks later we have the other motor and battery been shipped, with tracking number. Woohoo. Off the order goes. Watch it for 5 days, and on the day the status changes to the where it is destined we get an update. Turns out, they gave us the wrong tracking number, cause our package was off to Brazil.
Really hate this guy by now. More emails, more hope, more disappointment. Another 2 weeks pass, and we finally get the tracking number. Success. We track for another 8 days and by some miracle it comes to Australia. Package arrives and is picked up. Open it up, and there is one motor, its the 6900 instead of the 5700, and no battery or connectors.
Can this guy be any more useless. This is beyond a joke.
That was half a week ago, which is a 3 month wait on an order. Still no word on the other items. Just wanted to share the horror story. It in the end, every update made you laugh, cause any other reaction was not going to be any good. Mamba Max is awesome though, but i will never order off these people again….ever.
Today I took the Durga out with Dan. But unlike last time we met, we were packing some power. In my car I had the Mamba Max 6900kV (a post on how this came to be soon), while Dan was sporting the Mamba Max 5700kV. These motors were a serious step up from what we were running before.
I had only finished the install last night, so was excited about giving it a run. We went to a BMX track, which consists of a very loose dirt surface, and some jumps designed for BMX bikes.
I popped my car down on the track and hit full throttle. BAM…..the tire had come off and was now on the steering arm. Total, 2 seconds. Hmmmmm. Some glue and a 5 minute conversation about the power, and the car was ready for take two.
Dan lead off, and I had to admire the speed of his car. Not to be outdone, i gave my car a little gas and followed him down the dirt track. That was the point the brain fart kicked in, and I thought, i have more power, I’ll just full throttle and overtake, cementing some kind of authority on the situation. I gave it full power, started to catch Dan, and then hit the jump at full speed. The car flew well, it took off like a rocket, and well, didnt land so good. I didnt get the privilege of seeing the landing, just got the pleasure of seeing the car bouncing and spinning as high as the jump (which was about 3/4 my height). I giggled a bit, and went over to put the car on all fours. Alas, the car was not going any more. You could hear the motor spinning, but nothing else happened. Bugger.
Funnily enough, Dan’s car was having issues as well (sympathy problems) so we pulled them apart and fixed em up. Luckily, the motor had just moved and the pinion wasn’t touching the spur anymore.
Back out we go, and I can’t control the thing. It was all over the place, as soon as you had the idea that you were good and gave it full throttle, around it would go. It was out of control. It would go sideways round bends past you, flicking stones in your face. It was wonderful. Dan was having alot more luck with his car, and it seemed to be planted. The banked bends were no trouble as it slid around them. Mine on the other hand, was good at tricking you. As soon as you felt good, it would turn a bit much and off the track it went. In the end, half throttle seemed the ticket and I was getting some better control.
After getting the hang of it, disaster struck. Going round our “track” i noticed that the car was not turning so good. Straight was right, left was right, right was super right. Once again, something had given way to the force. This time, the suspension had fallen off. Luckily all the parts were in one place. Another repair and back at it.
We decided to change venues as the ratio of rc car vs BMX bikes was starting to be unfavorable. We chose a car park. It ended up been a poor choice, but it was one place we could wind the cars up. The best was to describe the way the durga looked, was a speed boat across water. It was hitting the small ditches and just skimming across the land. It was amazing. But like all good things, it came to an end, when the front suspension arm came off, and the durga was skimming with 3 wheels.
After repairing it again, we went back to the BMX track for the final run. Front suspension fell off this time, and once again there were just too many people so we called it a day. Dan did get a shot at the lipo in the final run, and it turned the 5700 into an uncontrollable beast as well.
So what was learnt today:
But most importantly, we really need to slow down and learn to drive. The jump is enormous, and right now the control is not there. Its one thing to spin the car and make mini tornado’s of dirt, but its another to have some control. Right now, the 6900 appears to be the stronger, but it no good if it is not on the track. I need to turn off the part of the brain that just wants to gun it, and take a bit of time at 1/2 throttle going round the track. You don’t have to be fastest, you just need to be consistent.
After cracking the purple shell it was time to get a new shell and give the car a new look. The shell i chose was a HPI Mazda RX7, and i also grabbed some new proline rims to match the new paint job. The colour is the Tamiya Metallic Blue in case you’re wondering.
So say goodbye to the purple car, and make welcome the blue car.
