Aviator 25

I have an old Thunder Tiger F-91S that I have only ran a few times. The other day I got it out and checked it over, it has not run in over 7 years. and some parts on it are looking in bad shape. Is there someone on the web that sells parts for these engines?

Also I was wondering what other people thought of these engines, my self I found that this engine in the past never really ran that good. It was a real pain getting it tuned in. Lots of power, but if I got the top end tuned in the bottom end would be out and if I tuned the bottom then the top was out. I don't know if this engine is worth the time.

JettPilot

My Feedback: (6)

Get a Saito !!!! Unless you like going to the field and fiddling with an engine all day rather than flying....

Sport_Pilot

It is a very good engine. You should be able to get parts for it by calling www.thundertiger4u.com. I dont' think all parts are called out on the web page. The engine is easy to tune, but only after well broken in, and with the choke adaptor installed. Only real problem is that the rocker cradle can come off when the single bolt holding it backs out. Remove that bolt and put some locktite on it and it will out run a Saito .91. In fact it will keep up or outrun some Saito 1.0's with a 14x6 prop.

djlyon

It's a real good strong motor. Got a lot of time on mine towing around a Deweyville Special. Ran great right out of the box. Couple tanks of fuel and it was ready to go, and go it did. Never needed the choke adapter. Sports right on the rocker cradle bolt. Lock-tite it.

Denis

Flyboy Dave

My Feedback: (21)

If one was to read all the posts in the Glow Engines Forum over the past
4 years, or so....one would see that the Thunder Tiger .91FS probably has
more problems than all of the other .91 FS's combined.

Don't believe me ? Do a search. I don't really take pleasure on dumping on
a particular Brand of engines. The fact is....the "other brands", have better
quality, reliability, parts availability, and warranty than the Thunder Tigers.

There are a few RCU Members that like the Thunder Tigers, and I respect that.
However, you couldn't give me a Thunder Tiger .91FS. []

FBD.

Sport_Pilot

One can pull many posts on TT engines and see that they are of high quality! The only real problem is the fact that they put an oversized carb on it and made a quick fix with an underbored choke adaptor. Without saying anything in the instruction manual. A problem I understand they have fixed by using a smaller carb. As for as having a single screw to hold down the rocker cradle, that is a problem shared by other four strokes and putting lock tite on that screw is good insurance. The only other problem is that it is the heaviest 90 sized four stroke out there.

Kmot

My Feedback: (24)

djlyon: Would you happen to have any pictures of your Deweyville Special? I have a NIB kit that I have had for around 25+ years. I never did see one actually built, except for the box cover art.

Thanks!

djlyon

Yes but I'll have to find it.

I also bought mine about 25 years ago. I built it about 2 years ago. The wood was so bad I threw most away. I chucked all the ply. I also chucked the cowl and built it out of wood. Basically I scratch built it using the plans. It's a nice looking plane and flys well.

Denis

djlyon

I will have to say in support of what Flyboy Dave says. That even though all my TTs run very well, 2 cycles and 4 cycles, I did find quality problems with the 4 cycles and early 2 cycles. The problems were such that they could be called "contempt for the customer" problems rather than mere quality problems. Parts support seems to be non existant.

Denis

Sport_Pilot

Parts are hard to find at local hobby shops because Tower doesn't carry them. You can find them on the web, a new site that is just TT is http://www.thundertiger4u.com. Customer support took a downturn during the transfer of ACE ownership to TT, but I understand it is improved. At least it was better the last time I called them with a technical question than before.

djlyon

Here's the Deweyville

djlyon

After thinking about it I need to add this. I did have a bearing retainer fail in a TT40 PRO and it did do a lot of damage to the engine. I sent the engine to TT and they replaced the bearings, head, piston and cylinder and as I recall charged me $28 (it was out of warrentee) and had it back to me in a week. I certainly can't complain about that. But I still couldn't buy parts and I still say problems I saw in some of their engines went beyond mere quality control. The bearing was a quality Japanese bearing as has been every bearing I've seen in the TTs. Never saw the no-name Chinese or Turkish bearings some seem to find in TTs. I've used several TT40 PROs (pylon racing) and those built in the last 3 or 4 years seem to be very good with no quality problems. Earlier TT40 PROs I saw were a mess.

Kmot

My Feedback: (24)

Thanks for the pics! It looks great! [sm=thumbup.gif]

Flyboy Dave

My Feedback: (21)

I'm not a Thunder Tiger fan. They were the ones that first pirated (stole) the
OS Max engine designs, and started producing copies of those engines. Their
quality was appalling. There was no way to get a flight out of one, they would
fall apart in the air. The mufflers and carb parts would come apart first, then you
would start seeing the head gasket leaks. Problem was, when you tried to
tighten the screws, they would strip out due to poor quality materials, and/or
faulty workmanship.

I always wondered how they got away by stealing another manufacturers designs.
I believe Thunder Tiger made engines for Magnum in the early days. These engines
were of poor quality as well, and gave Magnum a bad name at first. Magnum
finally started building their own engines, and the quality went from stink-poor
to top notch. Again, the only way to get a decent flight out of the engine was
take out all the screws, and either Lock-Tite or CA them back in to keep from
losing them, or having them strip out on their own. In some cases the threads
would come out with the screw....really testing the patience of the owner. The
thread holes were not cleaned properly when the threads were tapped. The
debris in the hole would cause the threads to strip when you removed the
screws. Parts were never easy to get.

I saw many new Thunder Tigers fall apart at the field, and my freinds wrestled
with them too. They bought them because of the low price. They wrestled with
the Magnum engines made by TT as well.

I didn't buy my first Magnum untill after they dumped Thunder Tiger. I've had
good luck with the new high quality Magnums. These two .40's are the first
ones I bought. They both started with the first flip of the propeller. I go over
all new engines, so there wasn't a problem with parts falling off.

FBD.

XJet

I've got quite a few TT engines (3x 46Pros, 1x 91FS, 1x 61GP) and they all run flawlessly.

The 91FS easily puts out as much power as my Saito FA100 when both are run on 10% nitro and none of my TTs have given me any problems.

one of the 46Pros has done over 200 hours and needed its bearings changed a few months back, but that's to be expected when you put up that much time.

While other clubmembers struggle with GMS, SuperTigre, and a raft of other engines, I just go out, fuel up, hook up the glow clip and my TTs start within a couple of flicks. They never dead-stick (unless I run out of fuel) and they put out really good power for their size.

Best of all, they're GREAT value. The 46Pro is probably the best value in its class at just $74, the 91FS is possibly the cheapest 91 four-stroke on the market and the GP61 I recently bought gives an ST91 a good run for its money -- at a significantly lower price and without the rich midrange.

After trying many of the no-name Chinese options (with very spotty results), I'm sticking with my Thunder Tiger and Saito engines.

William Robison

My Feedback: (3)

The only thing wrong with Thunder Tiger is their stupid name. Sounds like something you'd find in a comic book.

My son's first engine when he got back in rc about ten-twelve years ago was a TT 46, it still runs fine.

I have a Magnum 25GP (TT made) about 20 years old. It too still runs fine.

Bill.

NM2K

My Feedback: (14)

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I have owned and flown their .46 Pro, 1.20 Pro(s), .36 heli and I have two NIB .15s by them, having flown a friend's .15 and was impressed with its utility. I have yet to own/operate one of their four-strokes.

Some of the early TT engines had issues, but those seem to have been resolved long, long ago. The TTs I have are among my favorites.

Sport_Pilot

They didnt't steal OS designs, they stole their chief engineer. Besides all is fair as long as you don't duplicate a patent. OS and Enya copied Fox when they got started, so they got their due.

speedster 1919

My Feedback: (3)

Patends don't mean much when you manufacture in a different country. They would sell copies all over the world except in Japan where the design came from if Japan protects their manufactures.

Sport_Pilot

Sorry, but they do. If they are sold in the country that the patent is filed under they can be sued and the courts will demand a royality or lump sum payment. The courts can even bar sales. I recall that happened to Kodak's intant cameras, manufactured in a differant country. Kodak had to quit selling them and had to pay a huge cash settlement to Polaroid. You can only get away with it if they are not sold in that country.

Sport_Pilot

Link for TT parts.

http://www.thundertiger4u.com/engine...page=1&sort=2a

JRO

My TT91 4 stroke had to have over a gallon of fuel run thru it before it started performing. I own a OS91, a YS 91 AC and a Magnum 91 all 4 storkes. My TT91 with a 14X6 MA prop out performs all of them. Never any problems. Run like a champ, the only complaint I have is the high speed needle on the carb gets loose and I need to use fuel tubing so it will stay in place and not let air in to the carb. Also check the rocker arms and make sure the center bolt that hold the rocker arms in place stays tight. I run Magnum 15% fuel. I have used this engine on a 4 star 60, GP Cap 61 flew both of them great.

mentorman

My Feedback: (2)

I got mine at www.ehobbies.com after being referred by www.acehobby.com

ABORH

I will agree that the TT engines are fine. I have a 91 FS 2 54FS's 2TT46 Pros and a TT 6 1Pro. All of them run like the OS equivalent. The 91FS did break a rocker arm. But it was easily repaired. Parts arrived within 4 days of the order. In addition, I think they are a bit heavy so if you need a really light engine, perhaps another choice would be better for your application. I also run the following engines: Magnum 70 FS, OS 70 FS, Magnum 52 FS, YS 63FZ, 2 OS 120 Surpass IIIs and destroyed an OS 91 Surpass in a freak accident. All of them have behaved very well and have not given me any trouble. I use Wildcat 15% fuel. For what is worth....

obelix1

My Feedback: (1)

I've got a problem with my TT54, ever since I got it back from repair, it will trow the prop. There could be a shim missing or the timing could be off. Unfortunately, I don't have the manual anymore to check the timing. I would be grateful, if someone could scan and email me the timing setup and an explosion drawing if it exists.

Thanks for any help.

Obelix1