RTR out of the box crimbo morning

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I realised this thread has run from before I got the buggy until I first broke it, so, as it might be searched for I will fill in the other bits.

The car came in a box fully assembled with two small boxes one of which was empty and just to hold the car up in the bottom of the box, the other had the radio transmittor a small bag of spares (looks like a battery box cover, replacement servo horns and front bumper) and the manual.

The manual is a curious, bare minimum affair. Badly translated from german to English and another language (I didn't look which). It contains about 2 pages of printed text at least one of which is the usual "keep the safety nazi's happy with the disclaimer" the rest a VERY terse intro to the car and how to break in the engine, the later amounting to a 3 line paragraph! The rest of the manual is exploded assembly diagrams with part numbers labelled on them, handy, but no text explanation for anything. There are some spares listed and some tune up parts listed and then the same thing over again for the engine, parts, spares, assembly... There is no mention of the radio and how it works! So this needs the internet for info!

Out of the box, I added batteries to the battery box, 4xAA Duracells for now, rechargable 6v Rx pack will be one of the first add ons! I put the 8xAAs into the transmittor.

I installed the failsafe. <-- DO THIS! It's worth it, the range on these buggies is not perfect, especially if you leave the antenna down! I installed the fail safe by opening the Rx case (2 clips) and pulling the throttle servo out of it's socket, plugging in the failsafe, I had to use scissors to remove the tab on the failsafe plug! and plugging the throttle servo into the failsafe. I set the fail safe by pushing full brakes and pressing the button the failsafe, it lit up with the red setup light, so I released it. To test I set the throttle on WOT and switched the Tx off. Throttle servo immediately snapped to full brake and the failsafe light lit red again. Getting the extra wire out of the Rx case was a little tricky, it is doable, but be careful not to nip the wires in the edge of the case, if you have to push hard, it's gonna nick them, flatten them out more.

Then for the engine. I removed the cover sticker saying, "Read manual before starting engine", which made me laugh cause the manual tells you fook all. No Glow plug installed. I removed the airfilter from the carb, which required quite a fiddle and it's practically impossible to get back on with the cable tie still installed, so I removed it. I took my "Model Technics" after run oil and dropped 2 drops into the cylinder head and 2 drops into the carb opening. Then I pulled the pull start 5 or 6 times to spread the oil around. I was told ( and it makes perfect sense ) this will aid first starting as you will have lubed up the engine and made it slightly less tight to pull/run. I checked the carb idle opening and it looked fine, maybe a little small, but I could trim that out at first. Finally I installed the glowplug. I first tightened it down gentle, then pulled the pull start and could hear a hissing past the glowplug, a leak! So I tightened it down more. The glowplug copper gasket had been beveled like a real spark plug and needed to be cranked down to seal. It took another half turn before it took proper torque and no hiss.

I didn't want to touch the factory set needles for first start, so I left them all alone. I tested the radio gear and set the throttle trim to give a little more than 1mm opening in the carb. I pushed the air filter back on without the cable tie. I checked the engine mount screws were tight and a few other nuts and bolts here and there, all seemed tight, so not a Friday car and I was happy.

First start...

I left the car leaning up against a radiator (70*C) with only the top of the heat sink touching it while I prep'ed everything in the yard. Bear in mind my yard is a tiny little roofed in "antiroom" outside the back door and I live in a terrace house with nieghbours and it is like 9am on christmas morning.

I put the glow ignitor on the glow and left it while I filled the fuel tank, switched on the buggy and got ready, this would, at the expense of life of the glow plug, warm the cylinder and chamber.

I put my finger over the exhaust and pulled the start chord. Well, with a brand new tight as a jewish, virgin, mackerel engine you have to pull hard and it's very difficult to hold the buggy down and hold your thumb over the exhaust, so assistance is always good.

Now, first thing I will change on the buggy is the fuel lines. They are a beautiful florescent green that matches the car, but... you can't see the fuel in them. How you mean to know the carb has fuel when priming? You dont, end of. I pulled it 4 or 5 times with the exhaust plugged until I suddenly felt the pull chord become even stiffer... yep, she's got fuel.

Fuel, air, ignition (Glow ignitor) .. it should start.

I pulled it, and again, and again,.... about 20 times, nothing. Then just as I was beginning to sadden, "brrr". Just a burp. Another 5 pulls, "BrBrr". Then I remembered the like 3rd line of 5 on starting the engine in the manual said to advance the throttle trim 2-3 clicks. So I did, seeing the throttle servo arm open 3 tiny clicks. Pulled... pulled... "Brrr", pulled, "bbbBbrRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRR!!!!!!!!!", Fuc.. ee.....at's... oud!", "What!!!!??!!!?!?!?!?!"

I had to kill it by pinching the fuel line at the carb. It was too damn loud to run in a small confined space (with a door open to the air mind) and remain friends with the neighbours, but it had run!

Now, immediately that it ran I noticed a smell. I have run nitro engines before on 5% nitro, but this never smelt like my buggy did. The smell was almost sweet and fruity, perfume, not alcohol 2 stroke! I seriously suspect some fragrance additive is going on here in the Model Technics 20% fuel.

So off into the real car, de-ice the windows and set off to the playing fields. It's covered in ice and frost everywhere. We decided on the cinema car park, which was completely empty and covered in frost all over with patches of ice on what was puddles. Perfect. :D

Out came the buggy and we left it to idle (high idle) agaist the tool box and ran back to the car to start it up, rev the head off it and get full furnace heat going! Damn cold! 10 minutes later buggy was still singing away and temps were 108*C, slightly hot, I'm told. So, as my bro said, "Needs the airflow running over the head". I started running it around on the minimum throttle required to 'totter around'.

Now this works on paper and in forum posts that I should have done just that and only that on the first tank, but... in reality you can't help accidentally giving it more gas (OMG! I sound like an American!)... giving it more wellie from time to time. Just do TRY not to nail the thing! First tank got down to a wee fingers width and I brought it in, killed it pinching the fuel line... it revv'ed up then stalled, "Pinch test pass.". Back to the car and No. 4 on the fan heater!!!! Bl00dy freezing!

On the second tank, she seemed to want more throttle to get started from (close to) ambient, Engine: 30*C Ambient: -1*C LOL :) Petrol engines are like this too, they like a little more petrol when starting warmed. Fuel injected cars hide this from us, but I have a carb'ed motorbike.

We ripped it about at 1/2 throttle bringing it in every few laps and checking the temps. At one point the car, headed for a curb suddenly slammed the brakes on and spun to stop sideways. I knew I wasn't going to hit the curb, but I didn't slam the brakes on that hard. I tried to open the throttle and nothing. Then it clicked. The antenna was down! Pulled it up and out and the car responded again. THANK YOU FAIL SAFE!

The temps rose to 128*C at one point, TOO HOT. So I richened the mixture and strickly used 1/4 throttle to accelerate and let it slow down in the airflow, turned, repeated. Brought it in and ... 97*C. Much better. Engine sounding rich and floody, lots of blue smoke.

Third tank and I was getting bored and couldn't resist giving it WOT once or twice. The engine had taken more throttle trim to start this time, but when started and warmed it was sweet sounding, smooth purrrrrrrrrr, not prrrrrrrprrrrprprrrrprrrprr any more. I floored it and it went pppRRR..... Silence. I started it again and ran it and it took full throttle from half on the straight for a few seconds. Then I went back to 1/2 throttle ovals and eights.

Half way through the third tank I took a long run back to the base at 1/2 throttle, car was already going 20mph and I floored it, it shot towards me, past me, doing at least 40 and then I realised, 40mph + 4 meters to stop in = No. I slammed the brakes on, rapidly closing on the curb, threw it sideways trying to turn away and it just so... almost... stopped, but didn't. Patch of ice at the curb, 6 inches out from the curb a puddle of ice. BUMP. Pull away on the throttle, turn it towards us, it's not right and ... in sight now the rear left wheel is hanging off.

Stop it, kill the motor, pick it up, pack it away, go home. :(

At home, I de-fueled it, sucked the fuel back out of the tank and ran the engine dry of fuel, turned out it wouldn't start, which I took as good enough evidence there was no fuel in the system. Then out with the glow plug and 1 drop of after run oil in the cylinder and one in the carb, pull it through the engine. WOT helps. I cleaned off the oil with some Muc Off spray and kitchen roll :)

Find out what is broken.

Left rear hub carrier was broken clean in two at the lower suspension arm joint. No chance of field repair.

Dismantle it. Attempt to fix it.

Super glue to fix back together the clean breaks, but the bits were plastic has exploded out of, leaving a gap it was epoxy putty, some to mold like putty, but hardens like epoxy. I moulded this deep down into the cracks and holes and built up arond the superglued parts, filling in cracks. I checked all the pins aligned and it was the rhight shape. It dried for 1 hour and then was installed in the car. It gave loose when I tightened the wheel on! I cleaned it all off and repeated the process, this time I left it for 4 hours to dry and become completely hard before I installed it on the car. It will take weight, can be pushed up and down and dropped on it's wheels, but... it's a different thing being flicked into a donut at 20mph on a frozen car park.... it might not hold. Now the car is sitting with that wheel jacked up and I will try it tomorrow to see if it works.



Stay tuned for more.

PS, I will update with photos.

Cheers

Paul
 
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Haha good read. You pretty much summed up the frustrations and joys of nitro RC. :):)

It is very hard to restrain yourself from not giving it a good thrashing.
 
Aww man. The glued suspension held for another tank, but near the end of it, the radio went spastic, nailed it WOT and non-responsive, even with the fail safe. It spun on the ice it was on in a donut and finally swung out and pumelled itself into another curb, when the radio suddenly started working again.

Unfortunately the car didn't survive. The glued part broke and...

Bent right rear drive shaft. £9.99
Split right rear lower suspension arm. £6.99
Right suspension shaft bent. £7.50
Right shaft securing screw missing. £4.99
Right shaft spacer missing. £4.99
Front right knuckle retaining screw missing. £7.99 for a new knuckle pack.

Another £42.45 in parts :(

I can see this is expensive and running it in car parks with curbs and ice probably not wise.

Why did the radio go spastic? The antenna had pulled out of it's shaft at the first telescopic slide point and a few minutes later fell out. Why did the failsafe not work? Probably cause there was radio signal, it was just gibberish and slamed the throttle open.

Poor. Very poor.

But... half the fun is fixing them :D

Paul
 
Damn man, that sucks.

The failsafe should definitely have kicked in, hmmmm. Might be cheaper to get a digital 2.4 gHz radio before you bust any more parts.

This is a very good radio. It's made by Airtronics and has built in failsafe. Best of all it's not that expensive.
http://www.apexmodels.com/gbu0-prodshow/AR132000040.html

Sometimes the rx battery can go flat quicker than the failsafe can respond, It's happened to me once and it was only sheer luck that kept my truck in one piece. But this sure does sound like the radio is the culprit.

EDIT: after clicking the link the modelsport I can see that the radio it comes with is the 40mHz counterpart of the radio I linked to. There should be no reason to upgrade radio just yet. Maybe try getting hold of a friend and have him walk away with the radio on(car receiver on as well), and check the range of the system. All with the engine of. It might be a faulty crystal, as I've seen radios that would spas out as soon as you get more than 30feet from it.
 
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Aye, I'll be range checking it before next time. Rx batteries are Alkaline (Duracell) so they have a smooth discharge curve unlike rechargabled that go 6v... 6v... 6v... 1v in a matter of seconds.

Now... How in hell do you get the pins out of the axles? If I can't describe it here, I'll post a photo, but.. here goes...

The bit the wheel bolts onto that has a hex shape to grip the wheel and the shaft were the wheel bolt goes on, I'll refer to this as the outer axle. It slides over the inner axle, which has the drive shaft cup on the other side. This fixes it to the hub carrier. There is a steel pin that slides right down through the outer axle and through the inner axle and out the other side to sit flush on both sides of the hex bolt.

I have removed the tiny little hex bolt from the axle core, which I assume holds the pin in place and stops it flying out. However I expect it also slightly bends the pin and thus it takes it to be hit with a screw driver head to even move it and they are fiddly to hold in one place!

I have a hole in the left side of my thumb now :( The screwdriver slipped and smash straight through my thumb skin crushing into yellow seepy puss!

So, how the hell do you get those out without ending up in Casualty/ER!

Any suggestions/tips/tricks?

I need to get the axle out of the hub carrier as it's broken.

Good news is I was able to straighten the suspension arm shafts and the drive shaft has been beaten into being "almost" straight I think it's straight enough, don't have a fully assembled side of suspension to test it though :(

Cheers.

Paul
 
That pin "should" come out fairly easy when you remove the grub screw. Best I can think of is to put it in a vice and tap it out, but yeah they can be stuborn. In you case that one pin might have been bent ever so slightly from the crash.
 
Some photos.
http://www.campbell-multimedia.co.u...re.ShowItem&g2_itemId=8567&g2_navId=x57f382e8

I'll post again when I add more. So far.....

From box to first crash.

Shame no photos of it running, cause it was a screamer! Too fast for someone whose been away from RC for over 10 years!

Viewers... for extreme RC porn, just hit the link to the top right of the photo, looks like: "Full size: 3648x2736" Phhhaaawwww!
 
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So my shiny new alloy suspension parts arrived this morning, along with some rechargeable Tx and Rx batteries and some other spares.

Took the car out in the snow again and.... broke the front (plastic) suspension this time.

Might have been my fault. I was missing a left hub carrier bolt and the parts list said it came with the knuckle, but I got the knuckles no screw, with everything else fixed I hunted for any old bolt and put it in. It seems to came loose, fell out and allowed the suspension (brittle from being caked in snow) to snap. Just noticed the front bumper is cracked, but I'm not worried about that.

So now I can upgrade the front hub carriers to alloy too :) EDIT: Ooouch! Alloy front hub carriers are £46! That's like $75.

Anyone know a good source of general bolts? Like 4x2mm machine screw pan head? Local hardware store?

So I have got 5 tanks through it. It went kinda funny on me for a while, cutting out on throttle and "BuuBuu... Buuu...buuu BAAAA!!!!!!", way too lean, but I figured out the fuel line was kinked by the body shell and with a little bit of rearranging it went back to rich.

I'll wait for better weather and new suspension parts to tune it.

Cheers.
Paul
 
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I've got the same buggy there fast !!! heres mine
 
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my hobby shop told me 2 soak my air filter in some old fuel and then let it dry because the oil in that sticks to the air filter . hope i helped
 
Well, finally, it is no longer a bashing virgin.

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Took it's punishment well for the most part. Seems much more sturdy in a warmer climate (7*C) as opposed to icing conditions (-2*C). Went off a few jumps into a barrel roll followed by a cart wheel and end over ends it just just drove on afterwards.

Also jumped off a large slope and ... for some reason several times I thought it a good idea to hit the brakes for landing which resulted in burying the front end into the mud and throwing the car end over end at 20mph. No damage.

Actually the only damage I've found so far is the rear brake arm has come loose.

The engine is still in break in rich, but the tune seemed to change a lot and with me rolling it so often it kept getting air in the fuel line which doesn't help you track the tunning. Couple of times it wouldn't run without a tweak of the needles, so often that I got lost. It is still rich at least on the main needle as it has lots of smoke on full throttle, though it makes an impressive scream at full speed, might even be close. It BurbrbrbrrrrrRRRRR!s a lot, like bogging down when you nail the throttle, which I'm working on the principle the low end needle is rich and it's bogging down. Problem is... it could also be too lean and it's bababababaarr'ing cause it's starving until the full jet kicks in.

Ended up it kept cutting out completely on throttle. Thought it's too lean, but discovered it had actually run out of fuel DOH. The glow ignitor ran out of battery before I could bash it more. Back to factory settings now it's broken in and a good tunning next time out I think.

So, I'm fairly happy with the buggy. It takes huge air on jumps at the BMX course and survives my bad driving as long as there are no curbs to hit. Flat out on grass it's impressively fast, a little easy to roll on grass though, so you need to be careful. Engine, well the juries still out until I can get it to run, nice and tuned for a full tank without deciding it no longer likes those needle settings for some random reason all of a sudden.

Paul
 
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