branc11

Hi,
I'm looking to buy a 1/8 buggy to start playing with my son (he's 8 now) and would appreciate some advice from the expects in the field. I have some little experience with RC and I love nitro engines. Browsing around I saw some suggestions for RC 8.2 and Inferno mp9, but I have no experience at all too understand which one would fit better. Or even if another one is the best. This is a description of what we are looking for:
- Durability over all. I do not have all the time (I wish I had) to spend repairing it. I think we will not race for now, I suspect it will be mostly bashing.
- Our budget is limited to $500. We may go a little more for the accessories needed (e.g. started kit.)
- Easy to find repair parts.
- Not very complicated to drive.

BTW, I saw RC 8.2 FT is discontinued : http://www.teamassociated.com/cars_a.../Factory_Team/

Thank you,
Regards,

RustyUs

Welcome to RCU.

I would like to say I own a 1/8 scale buggy, but I don't. I'm moving in that direction myself. Everyone says 1/8 scale buggies make great bashers, and after owning a truggy, I've come to a conclusion that people are correct in saying so.

Just by looking over what you like in a vehicle....everything points to an electric 1/8 scale buggy IMO.

That being said, I know it's hard to change someone's mind when nitro fumes, and sound is a must. I've always wanted nitro something to mess with. A part of me still does want the nitro experience, but with plug-n-play power of brushless motors; pushed by LiPo batteries...It's hard to get excited about nitro at the moment.

RustyUs

Try looking at some of the offerings from Ofna, Arrma, and Associated RTRs.

I don't know if you have any radio gear or not that needs put into the equation.

branc11

Hi RustyUs,

I don't have any radio gear yet. Regarding, nitro vs electric, for me it is out of discussion, I really enjoy playing with the engine, the sound, the smell, etc. If there is one thing I would spend time with, that is the engine .

Thanks!

Guff15

I just bought an older OFNA Ultra LX Pro, and although I haven't had a chance to run it yet I can tell you that OFNA parts are easy to come by. I have a friend that owns a Hyper 7 TQ and he absolutely loves it. If $500 is your budget then the Hyper 7 TQ or even the Hyper SS will fit that budget.

Both come ready to run and it would leave enough cash for all of the extras (starter kit, fuel, extra glow plugs, etc.).

branc11

OFNA Hyper 7 TQ ordered, it should arrive next week (Tower Hobbies). I'm eagerly waiting for it to arrive, I'm already feeling like a kid again . Thank you Rusty and Guff for your advises!!

RustyUs

I hope to hear how you make out with that purchase and the performance from the engine. That Hyper 7 looks awesome!

Anthoop

Good choice, the Hyper7 is a great buggy for new comers and old pros.

It has been around for years...is tough...a mountain of spares/option parts...decent RTR engines..etc..etc..

Have fun.

branc11

OK, so my Hyper 7 arrived yesterday. Without much time and being very eager, we tried to start it but we couldn't. Tower Hobbies recommendations were to run the first two tanks with a 10% fuel. The user manual said to start with the carburetor needle on 3 1/2 turns open. Having confirmed the glow plug started is charged (tested the glow plug out of the engine), we couldn't get the engine to run. It does start, but quickly turns off and does not turn again. Any suggestion on what we may be doing wrong ? the fuel is a 10% fuel from Tower Hobbies, the glow plug the that came with the car.

Thank you !
Regards,

Anthoop

10% (nitro content) fuel is too low really...16% would be a minimum and 20% would make things far easier but 25--30 is what it will run best on.

For running in I use a lower nitro content fuel but this type of thing is not for inexperienced users as the engine will run like a bag of nails and be difficult to start/keep running...without changes to the engine and glow plug then 10% is out.

Regarding " carburetor needle on 3 1/2 turns"-
There are four adjustments on the carb. (providing it is either the Hyper.21 or Macstar.28)

HSN- this is the one where the fuel pipe attaches in the big brass housing....3.5 turns will be fine.
LSN- this is the black screw where the throttle linkage attaches....I recommend that this is set so that the screw head is 0.5mm out from flush for first start.
Idle screw- this is the small black screw protruding from the side...should be adjusted so that the slide gap is 1mm.
Finally there is the brass coloured screw with the brass surround (opposite end of the LSN)...this should be left alone and flush.

Adjusting the HSN will have little to no effect on starting and idle, you will need to pay attention to the LSN.

Guff15

I'm with Anthoop.....10% is low. I broke in my OS .21 engine in on 20% and still run it with that. Usually the needle settings come from the factory with settings allowing it to start, but sometimes adjusting is necessary. I'm not an expert but will tell you what I've learned.....

HSN was about 4 turns out. Whatever you do, do not over tighten the screw when starting over! As soon as you feel the screw getting a little harder going in, STOP. Then back it out to either 3 1/2-4 turns.

LSN I had to tighten just a bit to keep it running....maybe 1/2 turn in but I can't remember exactly how far, and yours may react different.

The idle I did have to adjust as it was way too open. Take the air filter tube off so you can see the carb slide. Adjust the idle screw until there is about a 1mm gap when it's closed. You may have to work the slide a little to see the true opening when the servo is in its closed position.

If you haven't already watch videos or read articles on the net about breaking in a nitro engine then please do so. This is the most important step to ensuring a long lasting nitro engine. They're all pretty much the same.

Also, expect to have a small mess after the first tank as it should have a lot of oil coming out of the exhaust during this time. Keep us posted on any troubles and/or progress!

branc11

I got it to to run ! It indeed was the fuel, as soon as I moved to 20% I started seeing better results. Anthoop, the engine that comes with the Hyper 7 TQ is a JL .28 and has only three screws. The main one (where the fuel hose is attached), a black one in the middle of the carburetor, and another one where the throttle servo attaches. As per what I figured out, I think they are the HSN, idle and and LSN respectively. I got the HSN a little over the factory recommendation at almost 4 turns open. The idle is easy to set with the engine running on idle, just get it not to high or low. Then the LSN gave me a little more work and I'm still working on it. I'm almost finishing the second tank. Sometimes, after running for some seconds going back to idle there is a little hiccup that I'm working on.

On other matter, I'm extremely concerned with something that happened yesterday with the buggy . While still tuning the engine in park with my son, suddenly the buggy stopped responding and went in full throttle in a direct line towards the highway. It crossed an entire soccer field at full throttle without answering any of the commands I was sending to stop or turn. Luckily enough, there was a dirt dry gutter before the highway and the car rolled there and stopped. I'm extremely concerned about what could have happened and planning to write to OFNA. After I got to the buggy, the radio was not responding any more. Could it have been that the receiver ran out of battery?? I haven't tested the transmitter/receiver any more. I had to change the glow plug and the engine started working again. After getting back home I read the entire manual and I was disappointed to see there is no way to know if the receiver is running out of battery. I saw there is a "Fail Safe" mode to set the car when it looses connection with the transmitter. However, this is not guaranteed to work if the receiver runs out of battery. This is disappointing. What would you think about this?

Guff15

Glad to hear you got it running. Hopefully you broke the engine in properly. Most nitro guys will tell you to idle the 1st tank, 1/4 throttle figure eights the 2nd, half throttle burst in straight lines for 3rd, 3/4 - full throttle burst for fourth, and longer full throttle bursts for 5th tank. Change glow plug and let her rip on subsequent tanks (after tuning of course)!

It sounds to me as if the receiver lost power, thus the throttle servo went WOT. Failsafes are designed to activate at a predetermined voltage, so when the voltage drops below that the failsafe should kick in, but still leave you with steering IF it still has a signal. I now have a Flysky GT3C and set my failsafe to activate the brake in the event it's needed.

If you set the failsafe in your receiver all you have to do to test it is turn off the transmitter, leaving the car/receiver on. The throttle servo should either return to neutral or apply the brake (depending on what the receiver will allow you to set).

Glad ad to hear it found the ditch instead of an immovable object or a real vehicle.

Anthoop

Ah right....I did wonder about the engine it came with over there....in the UK it is available with either of the two engines I mentioned.

Anyways good you got it going...getting the LSN set well can be tricky for a first timer, stick with it...as you have already noticed the LSN and slide gap work in conjunction with each other. If you are adjusting from rich and wide gap then as you lean it then the revs will rise and you will need to reduce the gap.....oh and only small turns on the LSN make big changes, slow and steady.

Yes, as Guff said, the failsafe should have low voltage detection...are you using AA batteries? If so, then ditch them and get a 6 volt battery pack....and fit a throttle return spring (or rubber band).
Fit both and check, check and check again that there is no way it will run away again....easy to test on the bench without the engine running....turn the both the RX and TX on and open throttle, turn TX off and failsafe should return the throttle to the failsafe setting....then turn both on again, open throttle and disconnect RX battery, return spring should return throttle to neutral.

Depending on which radio box you have will determine which battery pack you need, the older grey box can use both the hump pack and straight pack, whilst the newer black box can only use a hump pack.

branc11

Oh man something must be going wrong with my computer or the forum, I have written this answer three times and there is always an issue for it to get posted. Ok, here I go again.
After reviewing the car, I found that the battery plug in the RX was unplugged. I think this may have been the root cause. I know it may have unplugged during the roll. However, I’ll assume not. To avoid any further incidents I used a zip tie to keep the cables tight into the RX. I’m using a 1700 mah battery pack. I tested the fail safe mode (with the engine not running, obviously) by turning off the TX and seems to work. Have not yet tested removing the batteries from the RX.
Yesterday, we spent a couple more tanks and everything went fine. Tomorrow it is expected to be sunny, so we’ll go to a distant uncrowded park to run it more!
Thank you guys for your advices, have been really useful !

Anthoop

Yes I have had that trouble when posting before.....now (when it is a long winded post) I copy (cntrl+c) before I hit post...saves tears.

Something else worth mentioning about the radio box...I always pack them with foam/polystyrene/whatever to stop everything jiggling about...and to isolate the RX from vibration as much as possible.

Anyways let us hope that is the end of your runaways....have fun out there.

gigadiablo

HPI Trophy Flux Buggy

Anthoop

It will always help if you read the posts in the thread before replying....let me summarise for you:-

WVNed

I just did the same.

mkjohnston

My Feedback: (2)

you need to get a throttle return sping for you carb. I m not familiar with the engine in you car but it should have a slide valve type carb. Dynamite makes a return spring which hooks around the fuel intake nipple on one end and the other end goes around the the throttle ball link. This helps your throttle servo close the slide valve when you loose your battery power.its a bout 2.50 USD for two.