Friday, 30 September 2011

Bashing 30/09/2011

The sun is shining, I’m out of work early, i have a bag full of charged LiPo’s… would be rude not too!

Another bonus, i bloke i work with is a bit of a genius when it comes to correcting malformed bits of metal (advantage of being an engineer!) in my case, the bent Savage drive shaft. With a bit of heat work and a press, he managed to correct the shaft back into shape and retained its hardness absolutely perfect! Saving me about £25 in the process!

So it was off to the bashing grounds with both the Flux HP (wearing the battered X 4.6 shell) and the E-Revo to make its debut in the testing grounds.

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I really hoped to get some pictures of them both in action but managed to bust the LCD screen on my camera! So ill attempt that when i get it fixed.

The Savage was up first under full 6S power, the land is very dry and tough, so its not long before small dust clouds are rising into the atmosphere! For about 5 minutes anyway… as it then broke down!

Well, i say broke down, all i got from operating the trigger was the sound of a motor spinning round. Fearing the worst of a stripped spur gear, but then quickly remembering the fact the Flux HP has the metal spur gear, i feared the motor somehow had a fault.

As i made my way to the truck, it was instantly obvious and thankfully easy to fix.

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The grub screw had come loose and the pinion had slid along the shaft and “de-meshed” itself!

Being as I am only round the corner from home, i tend to not bring any toolkit items, but will start carrying a few basic tools i think, as back at the workshop all it took was an Allen key, and 10 seconds later it was ready to go again.

Never mind, at least i have the bonus of more than one model now, so the E-Revo got a good going over!

I have mixed opinions on the E-Revo’s off road ability. For one, running the 4S Carbon XX batteries it has bags of power, blistering acceleration and impressive top speed. The grip and handling are amazing, it is so easy to control this truck on loose ground. As i mentioned in an older post, the braking does need dialling back a bit, its very powerful, but just a little bit too much, and it can be easy to lock the wheels on soft and dusty area’s, which can end up having it stop sideways or backwards, need to get it like the Flux HP where it almost feels like it has ABS.

The dual servos on the steering, give it a massive boost when working against hard cornering, all it does is bite and turn. In comparison, it’s one thing i think the Savage is let down by. Sometimes the servo seems overwhelmed and can’t hold the position of the wheels and you end up under steering. The E-Revo doesn't suffer from that at all.

Hyper fast donuts can be had, and with a quick flick of the steering in the other direction, it will drift off leaving a huge ball of dust behind.

General bashing about over alternating terrain (tarmac, dust, sand, gravel, grass) at controlled speeds shows the E-Revo is a very capable circuit machine, i even got to the point where i had a small course mapped in my mind and continued to do laps of it, attempting to mentally beat my own lap times.

The only thing that’s slightly against the E-Revo is the ride height, I've always felt its more like a truggy than a monster truck, and it does show.

As you can imaging, it bottoms out quite a lot, where the Savage’s (and most likely its Nitro 3.3 brother) just glide across and eat up the bumps.

It didn't take long for the skid plates to be completely pot marked by rocks and such after hitting them, and sizable undulations in the terrain (such as buried boulders) cause it to buck about quite awkwardly if you haven't noticed them in time, again, the true monsters would just jump them or ride up on two wheels.

I don't, not like, it though, its a fabulous model and well worth the money, i just hope to get the 6S batteries into it soon and see what it can really do. It already pops wheelies with 4S under the right conditions, i think 6S will yield the same madness that the Flux HP see’s!

Also I'm hugely impressed on the sort of run times you can get from the LiPo and Brushless setups. As back in my younger days, 10 minutes of runtime from a 4000mah 7.2v battery, with a reasonably good and uprated motor, was almost myth and legend.

I was expecting this new fangled technology to deliver more power but only last as long, but with a huge combined 12,800mah and still pumping out at 14.8v i timed the truck from switching on, up until the ESC deciding the voltage was too low to continue, as just over 38minutes of runtime!

In one sense, when you are being careful and driving properly, rather than screaming round like a lunatic, the modern brushless setups have so much power at such lower throttle percentage, in proportion you are not demanding as much from the batteries, and you get the impressive runtimes.

Again from a previous post i only managed 10minutes, then an another 5minutes of “dying time” from the bundled NiMH batteries which are 16.8v with 6000mah (2x 8.4v @ 3000mah), and their full throttle top speed was probably only 30-40% of the 4S LiPo setup.

Thoroughly impressed i am, its worth the extra expense to go Brushless and LiPo.

Tuesday, 27 September 2011

Savage X ready to rock and roll…. again

On a plus note for the Savage X i receive a Jiffy Bag from Modelsport UK today and in there were the suspension components needed to replace the destroyed turnbuckle end-piece.

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The part number is 100949 and as you imagine you cant buy the single bit you want (unless your LHS will split a pack?) but at least there are plenty more spares to destroy…!

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A simple case of reassembling the turnbuckle and getting the ball joint installed the right way round, There is also a scale guide in the manual to help you set it up. Just be aware one end is a left handed thread! That threw me for a while!

Simply reattach to the upright and the chassis and the X is good to go again! Might treat it to a run out tomorrow…

First night out with the E-Revo

With both Savages out for the count, i decided to give the E-Revo a quick going over. I had decided to dedicate the weekend to the new Traxxas arm of the fleet, but with the random and nice weather we had today, it would have been rude not to get out.

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I started by installing the two bundled 8.4v 7cell NiMH batteries that come with the E-Revo kit. Lesson learned from jumping straight in with the 6S setup in the Savage HP!

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Onto the playing fields, straight line speed more or less was a bit dire! It was very “driving miss daisy” compared to the performance seen from the LiPo’d Flux HP recently. Even the motor itself sounded a bit bored!

But still, i managed to get a gentle break in of my own senses on how the E-Revo actually goes about the business of handling…. which is sublime!

Whether you think the trick suspension is just a gimmick or a masterpiece of model engineering, damn this thing can impress in the bends!

Now I’m no pro-racer and generally just enjoy trashing round, so handling is acceptable when the vehicle turns accurately enough when requested to do so, but the E-Revo is pin sharp in its control, the low centre of gravity and wide stance give this truck serious manoeuvring capability. The braking is also immense, i literally had some 30deg endo’s under some heavily applied moments. It perhaps wants backing off a little bit (using the Castle Creations Link - more info on this soon!) but its impressive non the less, and the car looks great under a heavy nose dive with the huge rear spoiler waving around in the air like a whale’s tail!

I have been used to my Savages being a bit hairy at speed, with body roll being a common demon which normally passes onto inevitable under or over steer, but tackling a narrow footpath with the E-Revo at speed and with a few practice runs makes it look like a giant slot car (if you squint a bit) I am seriously looking forward to getting it into the more testing off road area.

The NiMH batteries eventually wheezed their last breath after about 15minutes of constant full throttle, which wasn't too bad i suppose and ill perhaps keep them to one side if someone asks “for a go” with it!

But i needed to see what the E-Revo is really capable of… after all the Castle Creations Mamba Monster motor and ESC can handle the full 6S treatment…

Unfortunately my Overlander batteries have Deans plugs and i have no adaptor leads, but i have acquired a set of Orion Carbon XX packs. They are only 2S 7.4v LiPo’s but they do have a massive 6400mah capacity and specially shaped to fit the E-Revo’s battery compartments.

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You do have to remove some of the parts from the compartments that are there to stop batteries moving about, this includes the foam pad, the retaining spring and the bracket. Literally a 10 second job, the pad is simply stuck on and peels off, the clip requires you to pull it down and push it towards the centre line of the chassis and the bracket has one Allen screw.

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The battery then slots in perfectly, just safely tuck the balance lead in the spare space and the TRX connector leads through the slot provided…

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A match made in heaven to be honest, the sealed compartments are a far superior method to the HPI Savage idea of the battery “saddle bags” attached to the TVP Chassis plates.

Now the E-Revo really comes alive! You really have to experience the difference between the old NiMH technology and LiPo’s as the difference is astounding. The E-Revo now has some serious energy behind it, easily lifting the front wheels, if not as vicious as the Flux HP was, and the straight line speed is fantastic, whether it be grass, soil or tarmac the wheels are easy to spin, but thankfully it feels much more solid, much more planted. No sudden and scary back flips, but that is most likely down to the low C.o.G. and the fact that its only 4S. I'm sure with full 6S power (which ill try soon) it will become completely mental!

Sadly i didn't get to run the batteries to the cut off point as annoyingly the nights are rolling in and its too dark too quick, but i did get a reasonable 20minutes of run time and it still felt like it was ploughing on strong despite spending most of the time at full throttle screaming up and down the playing field.

As long as the weather holds out enough, ill get the Orion's pumped back up and see how well it does when the going gets a bit rougher.

Making the best of a bad situation - RC Car Action

I sympathise with this!

Making the best of a bad situation - RC Car Action

Monday, 26 September 2011

They say it comes in three’s

No truer word said when it comes to the Savage Flux HP!

But first… a quick review… (full one coming soon)

The HP has been the first of the new 3 to get the full test drive treatment.

Batteries selected are Overlander 3900mah 3S 11.1v packs. I wondered how these would fair with them being towards the budget end of LiPo batteries, but they seem well put together and have had zero charging problems with the so far.

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With a pair installed to the Flux HP and the ESC calibrated up on stands, i ventured onto the patio for a test run.

Here i got the first taster of the utterly brutal performance of the Tork motor when its under power from 6S worth of LiPo batteries.

In hindsight i was being a little under cautious and ended up pulling on the trigger a bit too much (about 50%), being used to the Nitro you forget how sudden an electric RC can pickup, and this was no exception!

The motor burst into life and the chassis literally took off into half a back flip, and flew a good 10-11meters across the patio slabs! My first crash and I'd not even gone anywhere yet!

In a state of shock and amusement, i reset the truck back onto its wheels and then proceeded with a bit more caution in order to get the trims corrected.

The instant feeling you get from the Savage HP is just the shear amount of grunt the thing has got, just taking it steady round the garden and getting a feel for the throttle has the motor yelping and lifting the front wheels off the floor.

After 10 minutes, id got the hang of going forwards and backwards, so went out to the street (late at night) so i could fine tune it to go in straight lines.

This gave me a chance to give the throttle a good squeeze and get the first experience of what the HP is capable of.

The motor sounds amazing under load! A sort of high pitched whine and a “rushing” sound, the back of the HP squats in submission and all 4 wheels start scrabbling for grip. Once enough bite has been mustered, the truck seriously shifts and before you know, it’s becoming a small dot in the distance.

Plenty of practice is need with the throttle, you cannot just tug and go with this thing as it will literally do a 1 and a half back flip from a standing start. Also the power has to be fed in when moving at pace. Again, hooking the trigger back will have it on the back wheels instantly, and failure to control the front end lifting will have the rear skid plate clip the floor, and the next thing you know, the truck is cartwheeling end over end!

The braking system is also seriously impressive, reversing the trigger causes the motor to work against the forward inertia, nose diving the front and scrubbing the tyres. The truck stops very quickly in a very controlled manner. Its almost as if it has ABS as the wheels never fully lock. A heavy braking period can easily be combined into a quick 180 tight turn and then rocket off in the other direction with the front wheels off the floor and the back wheels making dust clouds!

The following day i made way to a local playing field, thankfully deserted, to get some practice in before going fully off road.

The field is a moderately flat grass area, perfect for learning how the HP behaves, and get a grasp on the fine line of what constitutes a wheelie and what becomes a backflip!

Being as the rain came down a few minutes before hand, the wet grass also provides excellent substance for power slides and impressive plumes of moisture from the tyres at speed.

And then it went wrong….!

One long sweeping high speed corner and i came too close to the football posts in the fields… a loud “clang” ensued and the truck came quickly to a stop and to rest on its side.

As i got to the truck, one thing was certain… one of the rear wheels was facing the wrong direction!

A quick evaluation there and then revealed that the link rod/turnbuckle had snapped at the plastic end piece. So i duly limped home…

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Other than the spring being slightly dislodged from the shock, no other damage appeared to have been sustained, which pays homage to the Savage’s build quality once again.

Sadly, i have no spares! So they are on order. However the Savage X of course shares the suspension setup… and of course, the linkages! So its Nitro brother gave up its parts for the cause!

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Fast forward 24 hours (with the loaned parts) and a couple of LiPo’s ready to go, i decided to take it up a notch and venture to the wastelands where the Savage X gets most of its usage.

In this environment the Savage Flux HP is really an amazing machine, the effortless amount of power and torque has it thundering across the terrain and storming up sizable inclines like they are small bumps… normally followed by significant air time!

Very precise throttle control is required when in sandy or loose gravel areas as too much power will simply create dust clouds… and a back flip as per usual! But with the right amount of power will have dust streams, power slides and impressive “wheel-spin-wheelies”, as well as mountains of fun!

One main curiosity of this outing was to evaluate the run time of the installed Overlander batteries, and all was well (and mostly impressive) for about 20 minutes, when suddenly after a landing from a jump the truck seemed to behave in a strange manner. The jump wasn't a heavy landing nor did it come into contact with anything, but suddenly one of the rear wheels had lost alignment again… and it wasn't the left hand side, where the link rod had been damaged…

On first look, it was a link rod failure again, or so it seemed. On close inspection the mounting point on the upright had actually failed!

This is how i first saw the damage and as it was back at the workshop…

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This is a close up of the damage to the upright (straight through the thread)…

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Rest of the upright still attached to the link rod…

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Then a stroke of luck!

With the wheels off i noticed the uprights are ambidextrous. Meaning its the same part for each side, as confirmed from the manual. Part number 85048.

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Damaged upright, but with the intact lug as if it were to be installed on the other side.

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First the shoulder screws from the top and the bottom need removing…

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Also remove the hex hub and nut if they are there. Be careful you don't loose the alignment pin!

The upright with the axle will then come away…

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The link rods will need to be removed and retained on the side they came from. You cannot swap them between left and right due to the way they are constructed.

Look at the rod carefully and note the alignment of the ball in the socket. There is a round end and a flanged end. The flanged one is the face that clamps against the relative surface.

A screwdriver and a hex wrench are required to remove the link rod from the upright. Be careful not to loose the washer that is with the screw.

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With the rear suspension in a state of strip down, i decided to give everything a quick check over. Namely the suspension strut from the side that took the force of the pole crash that damage the first link rod. Thankfully it’s still fully functional and in good condition.

With the drive shafts loose and wrapped in grass from the field bashing, it would have been rude not to clean them up, and this is when i discovered this…

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I think i underestimated the amount of force that the truck sustained during that collision to bend a steel shaft in such a manner!

Its a miracle that nothing else was damaged more seriously! But this will require correcting before running the truck, as trying to keep this going will soon destroy the axles and probably the diff through vibration.

Ill attempt to straighten it tomorrow, other than that, it'll be new driveshaft's!

With a bit of luck the HP will then be able to live a happy life!

Its like Christmas!

Well…. the next 3 Christmas’…!

Announcing 3 new additions to the R-Garage fleet!

The HPI Savage Flux HP!

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The Traxxas E-Revo Brushless!

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The Traxxas Revo 3.3!

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Id like to thank Modelsport UK for providing an excellent service when acquiring these models and the excellent help and advice i have also so far received.

As you can imagine there are not enough hours in the day to complete a full review as of yet. However i will be working on, and testing all three trucks over the next few weeks. So please favourite or subscribe the site and come back soon!

Thursday, 22 September 2011

HPI Mini Recon

Recently announced 1/18th scale RTR 4WD monster truck by HPI. Part number #105502

Not seen in any UK based retail shops/websites as of yet, but a US one shows it to be around the $180 mark but on sale at $99, available in late October. - UPDATED! SEE COMMENTS

Early buzz and conversation on the Mini Recon seems to have most of the sceptics comparing it to similar models and claiming it to be a clone of other manufacturers, as well as being constructed of inferior or poor materials. Also several complaints of “WHYS THIS NOT BRUSHLESS???!!!!111!!”

Seriously… not everyone can afford brushless technology when they just want something cheap to play with, also newbies to the game are much less likely to ruin something with a tamer setup, which they can learn with and then move onto more serious equipment.
My honest opinion… some people need to return to reality, of course its not going to be of the highest calibre! Its a cheap and fun toy, not a serious professionals competition model!

Sure it “only” runs a small and brushed 370 motor. However it comes with everything you need including a 7.2 NiMh battery and a charger, the TF-40 2.4GHz radio is also included, and most of the basic makings of a bigger truck, with sufficient ground clearance, shaft drive, a servo saver, ball bearings and independent suspension. One would also assume HPI will produce some hop-ups for this model.

I think the Mini Recon would make an excellent gift for the younger R/C enthusiast, especially as the small scale will allow plenty of “yard bashing” at your own home.
I also expect it could be a fun indoor model for those excessively rainy days… and for annoying the cat!

 
minirecon1
Full details at the HPI Website

Thursday, 15 September 2011

Savage Slipper Clutch Repair

It took a while and a bit of trial and error, however the Savage is now running as strong as ever.

My original problem was the slipper clutch destroying itself… well i say itself but i think i may be partly to blame, being out of the game for several years, I'm a bit rusty on control techniques. Perhaps landing from hard jumps with the power still on and not respecting full throttle launches on rough terrain with such a massive engine, probably helped to kill it off!

First of all i tried a simple pad replacement. (HPI part #72131)

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Stripping down the slipper showed some heavy wear on the pad but it didn't seem completely trashed (I've seen worse!)

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It took a bit of work with the use of a craft knife to clear as much of the pad material out, but with it mostly cleared i noted that the 4 drive “dogs” that locate the pad appear to be also worn.

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I cleared the rest of the old glue with some fuel and a rag…

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Then attempted to apply a new pad…

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Its a bit easier to see the damage to the drives in this image, they are clearly worn and distorted, its obvious they have been in contact with the slipper plate.

One thing that wasn't completely obvious to me at this point (as i had nothing to reference it too) is that fact that there is a deformation around the central hole, its kind of a bulge or swelling, and the only thing that is giving it away on the previous image is how the camera flash is reflecting off the top off the central hole.

With the slipper and gearbox rebuilt i set out for a test run, sadly even with the replaced pad, the truck was going nowhere fast, with the slipper still spinning like mad, even with the recommended “tight and back one half turn” slipper setup as recommended by HPI.

Disheartened i decided to purchase a new spur gear and slipper plate. Part numbers 76937 and 72130 respective. Luckily the spur gear also includes a new pad.

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Unfortunately there are no more pictures from here as my camera battery died.

The thing that initially pointed to the deformation on the old gear is the new one is completely flat. I also had to remove the brass bush from the old gear.

This particular bush seemed to be literally embedded into the plastic of the old gear and the protrusion on the back face almost seemed like it had been caused by the bush trying to push its way though…? From this i evaluated that the deformed area was likely to be carrying most of the load from the clutch spring up against the slipper plate, so most of the energy was being lost due to the plastic spinning against the metal, and very little friction through the pad.

The bush took some getting out, with the use of a knife and punch, but eventually it was free and installed into the new gear, i also roughed the original slipper plate with some 180grit wet and dry (didn't use the new one in the end) and then proceeded to rebuild the rest of the drivetrain.

Taking the truck out provided instant results. It is now back on complete form and all the engine power is making its way through. In fact it seems to run better than ever, making me think the original slipper may have not been set right from the factory? I have also only back the spring of by a quarter turn instead of a half turn.

I also need to get some practice in and not be too excited with the throttle lever!

Further Reading

The HPI website has a tutorial on helping prolong the life of the spur gear, judging by the pictures, running it loose will completely destroy it! This is one reason i have decided to only back mine off for a quarter, as my last one was clearly starting to melt down in the same way.

http://www.hpieurope.com/walk.php?lang=en&id=13

Information related to the slipper pad….

http://www.hpieurope.com/walk.php?lang=en&id=9

And a worthwhile upgrade? The uprated steel spur gear found with some Savage kits, only thing is it requires a new clutch bell. So i may hang on until that needs replacing too…

http://www.hpieurope.com/piw.php?lang=en&partNo=77127

The Golden Rule of Nitro Models

Never underestimate how high maintenance they are!

Its been a while since my last post, and indeed my bashing time, unfortunately work and rest have outweighed play for a few weeks!

I did manage to make it to the quarry mentioned in the last post, however due to the slipper clutch eating itself, the experience was very short lived, and sadly the pads i had ordered never arrived in time for the particular outing.

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Had a short session and as per the pictures, a make shift ramp created some fun, there were plenty of superb areas and big heaps of gravel and the poorly Savage was clearly in its element. A return trip for definite in future.