Hello y’all,


I never thought I’d post on this subject matter which I think people have posted a lot about it. It’s about Thunder Tiger .46 Pro 2 Stroke engine and the fuel I use is Ritch’s 10%. I bought this engine from a reliable person and it was bench tested, ran few times, but I don’t think it was mounted on a plane and it was ever flown. I installed this motor on my Strega 40. First flight after the crash went well, prop was APC 11X5, it flew very well, did not have enough rpm as I would have wanted. It’s been like 3 weeks now, anyway, first flight I landed the plane due to uneven surface of our flying field it had a nose over, and nose over is a common thing. I fueled it up for the second flight, I tried almost everything that engine refused to start, finally I called it a day by being told that you need to clean up the carb as it’s gotten sand in it, I said fine. As my Mentor was there at the field, the other week I took it to my mentor, and he made me clean the carb with gum out spay, I made sure I squirted it enough to keep it completely cleaned, as I was tried to crank it up, it won’t fire up, I was told that it was not drawing fuel, may be the back plate is loose, while working at the engine I noticed a black hex screw came off and fell down on the floor, this is when I realized the back plate had last hex screw which fell off, so I realized that it happened during the flying at the flying field. Anyways, put the back plate on, tightened all the hex screws, and mounted the engine, now again it’s not drawing the fuel, I though GOD what the heck is going on, then I realized, Duh!!! I installed the muffler line to the carb and carb to the muffler, as soon as I changed it, I primed it and boom, cranked it up and it fired right up, we checked the idle rpm was 2,000 and WOT rpm was 12,600 to 12,800 which I personally think was good enough with an 11X5 APC on. Do y’all think it’s good rpm?


Last Sunday I went to the flying field, fueled it, and cranked it up and boom, here it goes. I’m using hot glow plug of Merlin’s, I’d try to use medium glow plug as well, now I just realized it might have been the problem too, it’s now gonna be another part of trouble-shooting. I tweaked the high speed needle towards the rich side, and took that baby up in the air, it flew really good without problem, and when I landed and I tried to taxi it back into the pit area, had a nose over, and chipped off the edge of the prop, as I was told not to use it, though it was maybe 1/16th or 1/8th of an inch, but I was told not to use the prop and change it, I did not have 11X5 with me, I had 11X4 and 11X6 for experiment purposes, I installed APC 11X4, somehow now the motor is not gonna accept this prop and I had to tweak a little bit but could not achieve the right rpm which I wanted, idle as well won’t tend to stay right, I had to change the throttle trim to high end, as it was not idling well, I took it up in the air, and I was not getting the right rpm, and while flying at ½ throttled, I had a dead stick, air speed was not good enough I could have brought it down, and it took a nose dive, thank GOD for tall grass and soft muddy surface, nothing happened to the plane, otherwise it was ready to go back to the recovery room or infirmary lol. Now I tried to crank it up after refueling, changed the plug, did the best I could, but this Thunder Tiger .46 Pro was stubborn like a pony that it won’t budge so, I did my best and finally called it a day. Now last thing’s left is to check out the medium hot glow plug, fuel is 10% Nitro of Ritch’s brewery, check out the fuel line, and take the tank off and check the inside and outside and all curves and crevices of it.


Now my question is what further steps may be taken to prevent it from happening, first flight goes well and second flight it starts going downhill, I’m gonna use the same 11X5 prop or may be 11X6, is it possible that motor could have been from the bad batch from manufacturers? I’ve seen one of my club’s member using new thunder tiger .46 Pro, and on ¾ throttle, it was screaming and flying their Ugly Stick so fast. Has anyone had a bad experience with Thunder Tiger .46 Pro 2 Stroke. All the inputs are appreciated.


Thanks y’all in advance

Mody


Here's the link for fuel tank issues

http://www.rcuniverse.com/forum/m_10525367/tm.htm

Now I understand your other post. I haven't tried the brand of fuel you are using but I have never found any of the store bought fuels to be bad or cause problems. What I have seen and had happen a lot more then once is no fuel draw after a hard nose in landing. Sometimes the main fuel line in the tank with the clunk on it will flip forward and get stuck in a top front corner. Give this a little thought and you will see why it doesn't draw fuel, it's not in the fuel, it's just sucking air. Before you remove the tank, grab your plane by the fuse and give it a good snapping shake and see if you can hear the clunk rattling around, before and after. The Pro series are great engines.

How old's your fuel?

Ihave a 9 year old TT Pro-.46 Ijust put it it's fifth airframe (a Saratoga 40). It's a hot little engine and has served me very well. Idid "suck dirt" once in the early days when it was two years oldand scoured the sleeve. I sent it back to TT and they replaced the sleeve and piston (no charge!). It's my favorite 2sengine but has one flaw - the needle valve stalk. After the crash mine never did seal out air. Isolved it somewhat by slipping fuel line over the outside of the stalk. Finally Iput a Perry carb on her. Inow get 14.4K with an 11 x 5 prop.and 15% S&Wfuel.

I too am puzzled by the erratic behavior of your TT Pro .46; to the best of my knowledge, there never has been a "bad batch" of this engine from Thunder Tiger. The Pro .46 is famous for easy starting and incredible reliability. The TT Pro .46 isn't particularly sensitive toward fuel or glow plug type, and the props you've been using are all within a comfortable range for the engine to turn. Any modern 10% to 15% nitro sport fuel should work well in a TT Pro .46, as should most any long medium-to-hot glow plug (with or without idle bar).

It doesn't sound like you're chasing an air leak to me, that usually manifests itself as erratic tuning rather than being hard to start. Most "engine" problems actually turn out to be plumbing/fuel tank related. Pulling your tank and inspecting your clunk setup and fuel lines could save you considerable time and frustration. Installing fresh fuel lines is inexpensive and will often clear up "engine trouble" even if you can't see exactly what the problem is on initial inspection.

It also wouldn't be a bad idea to try flushing out your needle valve assembly by pumping fuel through it backward to flush out anything that might be caught in it. A bit of gunk in the needle valve assembly can cause the kinds of intermittent run/start issues you're describing.

If you go through the fuel tank and plumbing thoroughly and you flush out the carburetor and you're still not getting reliable performance from your TT Pro .46, see if somebody else in your club could break it down and inspect the cylinder, liner, and bearings for you. Thunder Tiger Pro .46s want to run, and when they run they generally don't quit until simply run out of fuel. They're so reliable and so easy to start, that I use one on my Sea Master specifically for dead solid reliability when float flying.

Even though the engine might look lightly used, yours isn't running like it should. Your rpms are a bit lower than expected. If it isn't a fuel or plumbing problem, then it might be in need of a couple of replacement parts.

Guys Thank you very much for your great insights.

Gray Beard This is exactly what I thought and I was told to check the clunk if it got stuck or something, but it is not the case, I did not have to jolt the plane, I just tried to look at the clunk and it's well positioned, it does not touch the very end wall of the fuel tank otherwise it won't travel up and down well, it is not caught anywhere. Just like any other plane, the empty compartment for battery pack and receiver, I have glued a piece of balsa on top of it along with the fuselage walls so that they stay snugged and won't move.

Charlie P My fuel is not very old may be few months, it's Ritch's Brew's 10% Nitro. I have bought another fuel which is Morgan's for $5 or $6 lesser than I pay for Ritch's brew. As that old fuel of mine I'm sure would easily give me 10 to 18 flights, so I don't wanna stock it, but I might do something that, I can give it a try to new fuel and see what happens.

bigedmustafa I totally 100% agree with your statement, even myself I've never seen, heard anyone saying bad things about TT, one of the guy in my club, they bought brand new TT Pro .46 and they had it mounted on their super stick or ugly stick, it's an uncontrollable power house 1/2 to 3/4 throttle it was flying that plane like crazy, ample vertical. Changing the fuel lines, would change the behavior and exactly 12,800 rpms are not good enough as Charlie is getting above 14,000.

Now I'd the over-all inspection of it, I don't wanna unmount the motor, I'd take off the carb, and I have not seen a sealing ring/washer inside the carb, I'd take off the fuel tank which I don't wish to but got no choice, gotta do it, clean the fuel tank, change the fuel lines, and change the fuel and try it out, if all those trouble-shooting steps won't make it work, then I have already spoken to the seller, and he offered me his services, but I wanna look into the engine myself as I do have experience and I think I can pretty much resolve it, once it transcends by skills, then I might consult with y'all again or trying to send it back to the seller who is very honest person and has plenty of engines and I don't think that he would send me anything bad, I trust him 100%, he maintains a website and sells out all the engines, and I recommend him if anyone wants to buy engine, contact him with my reference Mody. Before he sends out the engine he makes sure it's running and no issues are there.

Here his website http://www.brucercengines.com/index.html

BTW. Today happens to be my Birthday, For a present or a gift to me, please PM me lol

Mody

If Ihave an engine that doesn't start -

#1 Is it getting fuel? If Idrip a drop into the cylinder does it fire? And, while Ihave the glow-plug out . . .

#2 Is the plug hot?

If it kicks after that and dies - is the carb jet blocked? Sometimes crud or a piece of plastic or fuel tube gets dragged in. Clear the jet.

If those are both yes and it still doesn't try to catch

#3 Is the fuel good? Try fresh or borrow a drop or twofrom someone&repeat #1

As noted, leaks in air cause problems, but only after the engine is running.

Hi Charlie,

I'm using Merlin's 2003 hot glow plug

http://merlinglowplugs.com/Aircraft.html

Fuel is not old, may be 3 to 4 months max. Carb's jet and every single part of it was cleaned out with gum out. I do not know if TT's carb has a ring/washer that goes along, if it does I never had one. I was not getting the correct idle as well after the second flight, I know TT or Magnum or ASP these are pretty much sturdy engines and would fire up under pretty much any conditions, that's my experience, but this engine seems to getting my down on my knees, but I ain't gonna give up on it. Anyway, the idle was not right, and I had to turn up the throttle trim in order to get it going, as I mentioned RPM was 12,600 or something like that, which is not up to par as compared to yours.

I think I asked already but didn't get the answer, if I may just run the rubbing alcohol through the gas tank fuel lines before I take it off and then change the plug to medium hot and use the new fuel, as I already have morgan's 10% fuel. If these don't help, then I'd probably take the tank off, if still this motor does not give in, then I'd prolly send it back to the seller as he offered me his services. I'm gonna carry out all those steps, and let y'all know.

Thanks again for y'all who posted here and trying to help me out.

Mody

Hi - I have been flying Thunder Tiger Pro .46s with OS #3 or #8 glowplugs for several years. I always buy new engines and break them in myself as I have purchased used engines and never been able to get them to run well. The only problem I have experienced with Thunder Tiger engines is sometimes they will want to start running in reverse, but that is the exception and not the rule. I have tried to fly on old fuel and that will cause problems. I have not tried Merlin glow plugs so I cannot comment on that, but I've had nothing but good luck flying these engines.

You mentioned you did not know if your engine had a ring washer or not. That could be a big problem, as there is a ring washer that fits between the carburator and the engine. There is also a gasket that sits between the muffler and the engine housing as well. Hope these tips will help. Here is a URL for an exploded view of the engine http://mms.tiger.tw/upload/2008-1/20081265128.pdf.

fix-n-fly,

Thank you very much for such informative feed back as well as the exploded view of the engine. I did see the ring that goes between engine and carb, and I don't recall I had that one, that could be the problem as well. I wanted to try TT and never heard a bad thing about it, but I guess it was my luck. I'm gonna take some other measures to run it, I'm gonna clean out the fuel tank, take the carb off and do few other things. As far as old fuel is concerned, my fuel is few months old, once I had old old fuel but may be a year maximum and it completely got discolored, whatever the pink color or dye it had it completely dissipated and ran all the fuel through the motors, not a problem, and this fuel is pretty good, but I'm gonna try out the new fuel. Merlin plugs seem to be working good, and I read and heard good thing about 'em as they have long heads as compared to O.S. plugs. Mostly engines require hot plugs, but I'm gonna try medium in it. I'd keep y'all posted.

Mody

Mody, did you buy this engine used??? The O-ring under the carb is there for a good reason and if you don't have one then it can cause a lot of different problems. When I buy a new engine the carb is usually not installed. The carb and O-ring need to be installed by the owner. You install the O-ring on the carb then push and hold the carb down with pressure and tighten the carb down with the screw. This stops air leaks. If you buy fuel in cans and keep it in a cool DRY place it doesn't go bad with age. You can keep it around for decades and it will still work. If you buy it in plastic jugs and keep it in a cool dry place out of the sun it will out last the plastic jugs. Loose caps in humid areas can allow moisture/water to get into your fuel and then it is no longer any good. If the cap is tight on your can it will last for decades. There are right ways and wrong ways to store your fuel, done correctly your fuel is never a problem, done wrong and you will be wondering why the new engine isn't running.

Add to the above...

CHECK ALL fuel nipples and fittings by inserting a pipe cleaner.

I've had people complaining about troubles with their engines... I run a pipe cleaner through all of the nipples, and it starts right up and works reliably.

All too often things get clogged, particularly the pressure nipple.

Gray Beard, opjose

Guys thanks a lot for your great inputs,

I'm sorry, the carb O ring is there, I thought it was not there, yes, I bought this engine used, but as it was only bench tested. First the back plate screws came off loose, then I had a nose over which caused the prop chipped out on the edge, I changed the prop from 11x5 to 11X4, did tweak but still did not get the right rpm, that I wanted. Had a dead stick on half throttle, low air speed caused plane to take a nose dive, Thank GOD the tall grass and muddy surf did not let my plane harm in anyway. Yesterday I pulled out the carb, so now I see the stopper screw at the carb that holds the throttle arm is missing, my LHS did not have it[:@] so they had to order one which would be there on Friday. I've been advised to use green locktight in order to keep it intact, otherwise, it would be lost again. This engine ain't a good luck for me, I'm unable to recall that I'd have so many problems with this engine, except for HB or HG german engine with perry carb, that .61 size motor got me on my knees.

Anyway, I'm gonna update y'all after this Friday, if I may be able to get it running, and nipples are all clear, and clunk is free not stuck, and fuel lines seem to be intact. If the stopper screw won't fix the issue, then I gotta think something else about it.

I'll keep y'all posted.

Thanks


Mody

On the site Fix gave us with the break down of the engine, are you saying #13 was missing or the screw that fits in the groove of the slide barrel came out? Doesn't mater, if you are missing either one you have a problem.

Gray,

I'm not missing the # 13, I'm missing the part G I think, anyway, here is the attachment.

Yes, I'm missing Bot & Set part G, and that's what I had my LHS order it and it's supposed to be here on Friday.

See there, you found your problem all by yourself.

Lol Thanks Gray

Loosing that bolt set does make a difference? as it runs through the throttle arm. If it's missing so what effect would it make on throttle arm?

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I believe that bolt is used to guide the barrel in and out so that the idle needle valve blocks off the fuel flow so that there is not too much fuel for idle. When this screw is in place the barrel will move in and out when it rotates. It may run wide open, but will die or idle bad hen you chop the throttle. It is not common for this screw to fall out from vibration. Suggest a drop of lock tite when you install it.

Sport Pilot,

Thank you very much for your reply. You hit right in to the bulls eye. After loosing the stopper screw, I did not know I lost it and the plane won't idle well, it would die down even full-throttle was not stable, and I saw for the first time when I cleaned the carb that this screw runs between the throttle arm barrel and now I know the function of that screw. I've been advised to use green locktite for it, as blue would melt down, red would completely make it impossible to come off in case I'd ever need it and green is best.

My LHS did not have it, and they ordered the screw for me, and expected to be there this Friday. I'm gonna update y'all once I get the engine back to running as I've seen this engine with my own eyes screaming, hardly heard any grumbling about this engine, so why am I getting so much problems? I hope that's the last resort.

Since March we are having bad winds and they are not ready to quit.

Happy flying