TT .39 heli engine ruens glow plugs
09-01-2012 | 07:47 PM
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From: Roseville,
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TT .39 heli engine ruens glow plugs
I have the Thunder Tiger .39 heli glow engine on a Raptor 30. The engine is starting to ruin glow plugs only after one flight. It also has a problem sucking in fuel while trying to start it.
09-01-2012 | 09:32 PM
#3
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RE: TT .39 heli engine ruens glow plugs
If you are having fuel delivery issues it is probably going lean and burning up the plugs. Check for things like cracked fuel nipples, ho;es in fuel lines , carbueretor gaskets leaking, loose fuel fittings etc.
09-02-2012 | 04:57 AM
#5
RE: TT .39 heli engine ruens glow plugs
One thing to do is to examine the glow plug element closely. You can use a jeweler's loupe or something else to get a good view of it. The glow plug element's condition can be very helpful in determining why you are ruining glow plugs.
Here is a good article on what to look for with a glow plug.
Here is a good article on what to look for with a glow plug.
09-03-2012 | 06:39 AM
#7
RE: TT .39 heli engine ruens glow plugs
I've used RTV to seal backplates, carbs, and mufflers for years. Never a problem with glow plugs. I am going to agree with previous responses; bearings or fuel delivery problem.
09-03-2012 | 04:59 PM
#8
RE: TT .39 heli engine ruens glow plugs
Before you run the engine again, take off the back plate and inspect the rear bearing. The bearing cage may be breaking apart. If so then a big chunk of it may breaks off and damage your piston and liner. That is what killed my Pro 46. I had several glow plugs go bad and I didn't realize what was happening until it was too late.
09-03-2012 | 06:30 PM
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RE: TT .39 heli engine ruens glow plugs
ORIGINAL: earlwb
One thing to do is to examine the glow plug element closely. You can use a jeweler's loupe or something else to get a good view of it. The glow plug element's condition can be very helpful in determining why you are ruining glow plugs.
Here is a good article on what to look for with a glow plug.
One thing to do is to examine the glow plug element closely. You can use a jeweler's loupe or something else to get a good view of it. The glow plug element's condition can be very helpful in determining why you are ruining glow plugs.
Here is a good article on what to look for with a glow plug.
I had a scrapbook of "Duke's Mixture" articles that got lost in a cross-country move of my household. I'd sure like to find some or all of them. Do you have a source?
TIA,
CR
09-04-2012 | 09:21 AM
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RE: TT .39 heli engine ruens glow plugs
The rear bearing is probably shot that sounds like it I'll check it. The glow plug looks like it's had someone stick a nail inside where the filament is. It's pushed in. I always use RTV in the muffler.
09-04-2012 | 09:39 AM
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RE: TT .39 heli engine ruens glow plugs
RTV to seal mufflers is a recipe for disaster. First, you don't need it. Second, if you use anything more than the very thinnest smear, it can/will fleck off and get sucked into the combustion chabmer during the intake portion of the stroke. If that happens it will snuff the glow plug immedately.
A properly faced muffler/engine joint doesn't need any gasket or RTV. If the surfaces aren't flat, then a thin smear of 5min epoxy will seal it without the issues of RTV
A properly faced muffler/engine joint doesn't need any gasket or RTV. If the surfaces aren't flat, then a thin smear of 5min epoxy will seal it without the issues of RTV
09-04-2012 | 10:23 AM
#12
RE: TT .39 heli engine ruens glow plugs
ORIGINAL: Charley
I had a scrapbook of "Duke's Mixture" articles that got lost in a cross-country move of my household. I'd sure like to find some or all of them. Do you have a source?
TIA,
CR
I had a scrapbook of "Duke's Mixture" articles that got lost in a cross-country move of my household. I'd sure like to find some or all of them. Do you have a source?
TIA,
CR
09-05-2012 | 04:39 AM
#13
RE: TT .39 heli engine ruens glow plugs
ORIGINAL: BarracudaHockey
RTV to seal mufflers is a recipe for disaster. First, you don't need it. Second, if you use anything more than the very thinnest smear, it can/will fleck off and get sucked into the combustion chabmer during the intake portion of the stroke. If that happens it will snuff the glow plug immedately.
A properly faced muffler/engine joint doesn't need any gasket or RTV. If the surfaces aren't flat, then a thin smear of 5min epoxy will seal it without the issues of RTV
RTV to seal mufflers is a recipe for disaster. First, you don't need it. Second, if you use anything more than the very thinnest smear, it can/will fleck off and get sucked into the combustion chabmer during the intake portion of the stroke. If that happens it will snuff the glow plug immedately.
A properly faced muffler/engine joint doesn't need any gasket or RTV. If the surfaces aren't flat, then a thin smear of 5min epoxy will seal it without the issues of RTV
No offense, but epoxy would be the LAST thing (remember, this is my opinion) I would ever use to "fix" a leaky mating surface. What would happen if a little fleck of that epoxy got into your engine...? That would be more damaging to the glow plug than a little silicone rubber IMO.
09-05-2012 | 05:17 AM
#15
RE: TT .39 heli engine ruens glow plugs
ORIGINAL: BarracudaHockey
To each his own, I'm only passing on my somewhat limited experience
To each his own, I'm only passing on my somewhat limited experience
09-05-2012 | 08:10 AM
#17
RE: TT .39 heli engine ruens glow plugs
ORIGINAL: Basil Yousif
I have the Thunder Tiger .39 heli glow engine on a Raptor 30. The engine is starting to ruin glow plugs only after one flight. It also has a problem sucking in fuel while trying to start it.
I have the Thunder Tiger .39 heli glow engine on a Raptor 30. The engine is starting to ruin glow plugs only after one flight. It also has a problem sucking in fuel while trying to start it.
Of course we do not know what fuel the OP is using. Too much nitromethane can be a problem if the engine isn't set up for it.
Also what brand glow plug is the OP using. The wrong heat range plug can be a problem. Years ago I got a batch of defective major band name plugs too. I went through one flight per plug, I never bought any of those brand plugs since then.
09-05-2012 | 11:30 AM
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RE: TT .39 heli engine ruens glow plugs
ORIGINAL: earlwb
Going back to the first post again. A problem sucking fuel implies a air leak somewhere. The O-ring under the carb is the first thing to check. You must push down on the carb hard to compress the O-ring a little before tightening up the screws or clamp. The next is the back plate might be loose. The head could be coming loose too. Then we get to the bearings, where the front bearing may not be sealing like it should leading to an airleak too. Then there is adjusting the engine to run too lean, heli engines tend to run a little more on the rich side than airplane engines do.
Of course we do not know what fuel the OP is using. Too much nitromethane can be a problem if the engine isn't set up for it.
Also what brand glow plug is the OP using. The wrong heat range plug can be a problem. Years ago I got a batch of defective major band name plugs too. I went through one flight per plug, I never bought any of those brand plugs since then.
ORIGINAL: Basil Yousif
I have the Thunder Tiger .39 heli glow engine on a Raptor 30. The engine is starting to ruin glow plugs only after one flight. It also has a problem sucking in fuel while trying to start it.
I have the Thunder Tiger .39 heli glow engine on a Raptor 30. The engine is starting to ruin glow plugs only after one flight. It also has a problem sucking in fuel while trying to start it.
Of course we do not know what fuel the OP is using. Too much nitromethane can be a problem if the engine isn't set up for it.
Also what brand glow plug is the OP using. The wrong heat range plug can be a problem. Years ago I got a batch of defective major band name plugs too. I went through one flight per plug, I never bought any of those brand plugs since then.
NEW ENGINE!
09-07-2012 | 11:15 AM
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From: Roseville,
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RE: TT .39 heli engine ruens glow plugs
I took the engine apart but I couldn't find andything wrong. Check the pictures out and see if there's anything that sticks out. The shaft and piston movments are smooth and have no play in fact pretty good for an engine that has ran for 4 years.
09-08-2012 | 10:15 AM
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From: Roseville,
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RE: TT .39 heli engine ruens glow plugs
So the bearings can still be bad even if they look good, I guess just a little bit of wear and the vibration can ruin the plug. The shaft does move with no play.
09-08-2012 | 12:22 PM
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RE: TT .39 heli engine ruens glow plugs
If the engine is apart its best to do the bearings. The only way to truly examine them is to remove them from the engine, put a side load on the bearing and turn it with your finger to see if its notchy, but for the price of a set from RC Bearings.com if you're going to do that you might as well throw them out and replace them.
Vibration won't make your plug go bad.
Running too lean, using RTV for a muffler gasket, and a bearing coming apart will make your plug go bad.
As for the RTV, if you use a very thin smear where none oozes out into the exhaust flange, you're fine, most people tend to over do it and it WILL snuff your plug immediately if if flecks off and gets back into the combustion chamber, this is well documented.
Vibration won't make your plug go bad.
Running too lean, using RTV for a muffler gasket, and a bearing coming apart will make your plug go bad.
As for the RTV, if you use a very thin smear where none oozes out into the exhaust flange, you're fine, most people tend to over do it and it WILL snuff your plug immediately if if flecks off and gets back into the combustion chamber, this is well documented.
