Glow Plug Problem

[Keith R.]

I was doing some 3D with my R50. Currently i have the TT50 in it (the OS is on order). What happened is when i was flying i herd this poping sound and then the engine died out. I managed to auto it down without any damage. After landing, i saw that the glow plug was missing. I am using Magnum 30% heli fuel and using the OS No. 8 glow plug. What do you guys think could have caused this?

Keith

[robe_uk]

have you checked the glow plug threats in the head of the engine, if they are ok then you most likely had a lose plug. Have you changed the plug recently? you should recheck the plug after first flight.
Glad you got her down ok

[Keith R.]

Yeah, the threads in the head are not stripped. I think that the plug might have been slightly loose, as it was flying like it kind of was. I guess that is one more thing to make sure to check before you fly :o

K

[syclic]

Hi Keith,

On June 30th (before your plug blew out) you had posted this in your thread on engines for your heli "I have been using the Thunder Tiger 50 Pro engine with my R50, but it is losing compression and power, so i am looking to upgrade."

If your plug was loose, it would have certainly caused it to have lost compression and loose power.

So I would bet that is why the plug blew out and also why your engine was down on power :)

[Ade]

ok... now i am worried... i agree with something syclic says :-)

Ade

[Keith R.]

Ok, just to clarify, the TT50 (with a new glowplug screwed in tight) still does not have lots of power, and runs the same as it did before the glow plug shot out. The engine is still down on power with the new glow plug in tight.

K

[King_Ice_Flash]

I have never gotten a good os #8 plug. The center insulators always leak or the center conductor blows right out of the glow plugs. This happened from 3 seperate orders of 6 plugs 2 years apart each. I won't ever use a os #8 again.

You should be able to see if the engine is leaking compression, either from the glow plug threads (If the head is damaged or plug is cross-threaded), gasket, or center post while it is running.

It wouldn't hurt to take the head off and see what the cyl/piston looks like.

I am assuming carb adjustment, fuel tank problems, or fuel isn't an issue.

[Paul Susbauer]

I hear a lot of people having good luck with Enya No. 3 plugs. That being said, I always run #8s, and the whole time I flew my Sceadu 50, about 30 gallons, I only replaced the plug once, and that was because I wanted to....how rich, or how lean you run, will determine how long your plugs last.

Just an aside....sorry to hijack the thread.

How much fuel is through the engine? Could it be that the ring is wearing? or is it too new? (I've seen your other posts, just don't remember what you said as far as run time)

Paul

[Ade]

how warm is the engine after the the flight. You might find that its running rich at the top end.

TT50 has a bit of a problem with a lean midrange. If tune the top and bottom to be ideal then you end up with a lean midrange which will overheat the engine in the hover.

there are 3 ways round this. Richen the top end which reduces power.

Richen the bottom end which makes the idle unreliable.

The third way involes modifying the idle needle. What happens with the TT carb is There is a main jet. The total fuel flow through this is affected by main needle

The main jet is also blocked by a needle. This needle is moved into the main jet at low throttle. it is also threaded, screwing it in leans the idle. The needle is tapered so that as it moves out at higher throttles it lets more fuel in.

the cross over between the low and high needles is about 80% throttle.

by changing the diameter of the needle at certain points you can richen the mixture at part throttles.

Ade

[Keith R.]

Ok, i've got the engine figured out...finally. The reason that the TT50 is not as powerful is because the ring is a bit worn out. I suspect that the previous owner didnt treat the engine too kindly, as it has only been threw around 12 gallons. With that being said, i think i am just going to put in the OS 50 that i got and let the TT50 collect dust on the work bench.

Ade- The mixture it spot on. I am running the engine at 200*F. I saw what you were talking about with the needles when i first got the heli and was tuning it.

Thanks for all the help and advise

K

[Ade]

i measure temperature by touch how does 200f compare to back plate finger test? if it hurts in less than 10secs its too hot.

Ade

[King_Ice_Flash]

i measure temperature by touch how does 200f compare to back plate finger test? if it hurts in less than 10secs its too hot.

Ade
I gave up on that after I touched the muffler once. On-board temp sensor is the way to go.

Glad you got it figured out Keith. After putting the OS-50 SX-H and a Hatori JKS in mine I haven't ever looked back. I wouldn't even bother leaving the TT engine on the bench. Just kind of accidently knock it off the table in into the rubbish bin when you get the chance. I would feel guilty even selling a TT engine to someone on eBay.

[Keith R.]

It is hotter than the 10 seconds. Its more like 2 seconds...if that (but then again i have sensative fingers). For me, 10 seconds is around 160*. I know with my nitro cars you want to tune them to run around 200*, so that is what the TT was tuned to. What is the best temperature for the OS50 to be tuned to?

K