Nitro R.C Car, help much appreciated.

[Mini1275]

Been using it loads the last few days. One thing though, the throttle stuck open today, i shut it off and started it up and it was fine?. There was quite a lot of muck underneath () could this of been it?.
Cheers again
m.1275

[Mighty Flex]

There are a couple of reasons for the throttle sticking open:
Loss of radio signal, such that the servos freeze in their last position, say fully open throttle and turning right. or their may be somthing stuck there holding the throttle open (even somthing like the bodyshell getting caught after an impact, depnding on the car.
If its fine now, not much to worry about. but i would reccommend buying a failsafe for ~ £10, which will return the throttle to a set position if you loose radio signal.

[Mini1275]

Mighty Flex said:

There are a couple of reasons for the throttle sticking open:
Loss of radio signal, such that the servos freeze in their last position, say fully open throttle and turning right. or their may be somthing stuck there holding the throttle open (even somthing like the bodyshell getting caught after an impact, depnding on the car.
If its fine now, not much to worry about. but i would reccommend buying a failsafe for ~ £10, which will return the throttle to a set position if you loose radio signal.

Will do!. It stuck open after i caught a bump and got some air.

[hman]

That sounds more like a mechanical fault in the servo, or linkage, or carb slider/barrell.

Or it could be the plug/lead to the servo.

Check your connections and see if you can get it to reproduce the fault.

Did you still have steering? if not thten the rx batt could have been disconencted or the rx may have a crack in the pcb ( good idea to wrap your rx in bubblewrap)

[Mini1275]

hman said:

That sounds more like a mechanical fault in the servo, or linkage, or carb slider/barrell.

Or it could be the plug/lead to the servo.

Check your connections and see if you can get it to reproduce the fault.

Did you still have steering? if not thten the rx batt could have been disconencted or the rx may have a crack in the pcb ( good idea to wrap your rx in bubblewrap)

Yep, still had steering.

[tr7v8]

hman said:

tr7v8 said:

hman said:

ha!,
well some do and some dont!


Personally I've never had to use unleaded to get my aero glow engines to start, wouldnt reccomend it either.

How low a temp have you flown in? Around the 0 Deg mark they are not only reluctant to start but also won't tick over so a small (egg cup in 5 litres) solves the problem. This is for either straight or 5% fuel.
But I'll bow to your greater knowledge, as I've only been aero modelling for 44 years

Meh, I've been flying since I was 9! I'm 35 this year so whilst I'm obviously young than you (ha!)I still have 24 years glow IC experience- does the learning process get easier in the next 20 years?

I dont use straight fuel, normally 10/15% in my older engines (laser, os, irvine, sc) and 30% in my Saito's (no bearing failures yet!)-- this may be why I have never had a starting/idling problem at the temps you speak of. All my flying is fixed wing (have been there and done the heli thing).

I've heard of people doing it, however I've never actually known anyone doing it. Apart from yourself.

This is quite high nitro level for bigger engines typically I run 5% Max in the motley collection I have, HGK, OS, SC & ASP. I'd only run 15% on small 0.06 stuff & Baby Bees etc. That is why you don't have an issue; also I bet you use an eleccy starter all the time? I don't, I hand start all my engines.
Yup been aeromodelling a long time hence the grey hairs of what is left. Don't get too much time these days with assisting to run a Porsche club & other bits so have let membership lapse this year. When I lived in Norfolk there was always a fallow field I could use for a quick hour of flying, now I have to load the car & drive 50 minutes so it just don't happen.

[hman]

tr7v8 said:

hman said:

tr7v8 said:

hman said:

ha!,
well some do and some dont!


Personally I've never had to use unleaded to get my aero glow engines to start, wouldnt reccomend it either.

How low a temp have you flown in? Around the 0 Deg mark they are not only reluctant to start but also won't tick over so a small (egg cup in 5 litres) solves the problem. This is for either straight or 5% fuel.
But I'll bow to your greater knowledge, as I've only been aero modelling for 44 years

Meh, I've been flying since I was 9! I'm 35 this year so whilst I'm obviously young than you (ha!)I still have 24 years glow IC experience- does the learning process get easier in the next 20 years?

I dont use straight fuel, normally 10/15% in my older engines (laser, os, irvine, sc) and 30% in my Saito's (no bearing failures yet!)-- this may be why I have never had a starting/idling problem at the temps you speak of. All my flying is fixed wing (have been there and done the heli thing).

I've heard of people doing it, however I've never actually known anyone doing it. Apart from yourself.

I bet you use an eleccy starter all the time? I don't, I hand start all my engines.

Damn right I use an electric start!, I like my fingers too much (saito 180 (29cc) +18" prop + fingers = no hand)

[Mini1275]

Report back, ran 6 tanks through and the car ran fine, no sticking of the throttle.
cheers

[The_Jackal]

A throttle return spring can be a useful extra safety feature too. If you lose battery power a failsafe cannot return the throttle.

[Mighty Flex]

out of control rc cars can do serious damage - i saw a 1/5th scale fg with the throttle stuck open end up under a focus st, and it lifted the car up a few inches getting wedged in under it...

[theshrew]

For your battery pack in the car makesure it cant come out or un plugged. Use a fail safe and keep the electrics dry a tiny bit of water can make them fail.

As for your running issues

Id defo would not recomend putting petrol in the fuel.

You have to understand that the engines are a pain in the backside, especially in cold weather and need to be tuned to the temp. One day it will run sweet as a nut the next it will be rubbish. Always carry a spare glow plug with you as they are pretty un reliable.

A simple tip on how to make it faster with not a lot of messing about. Stick a tuned exhaust pipe on it. Will make a fairly big differance.

[Mini1275]

Hi again, went to fill the car up again yesterday after running a tank through. After the body was put back on etc, the roto-start would not turn (kept locking/jamming). Eventually it turned and started but the car sounded very rough and you had to keep the revs built up. As soon as you took your finger off the throttle it made a racket (like something loose rattling around) and cut out.
Could anyone help and sorry to be a nuiscance!
cheers

[slomax]

Mini1275 said:

Hi again, went to fill the car up again yesterday after running a tank through. After the body was put back on etc, the roto-start would not turn (kept locking/jamming). Eventually it turned and started but the car sounded very rough and you had to keep the revs built up. As soon as you took your finger off the throttle it made a racket (like something loose rattling around) and cut out.
Could anyone help and sorry to be a nuiscance!
cheers

Sounds like you flooded the engine and forced it to turn over, breaking something in doing so. You can either strip the engine down and get the nescessary replacement parts and rebuild (or get someone to do it for you) or replace the hole engine. If/when it happens again as soon as you feel like its strugling to turn over or a bit stiff to rotate stop immediately, remove the glow plug and turn the engine over. This will get all of the excess fuel out of the chamber. Replace glow plug and try again. The other possibility is that the flywheel is loose and isnt rotating with the engine, causing it to cut out at low revs and rattle.

Edited by slomax on Tuesday 9th March 23:49