ke6gkc

I just bench ran a new TT pro 40 for my SRM2. What a sweet engine, started on the first flip of the prop. I have run 3 tanks through it at this time and no electric stater yet. Just thought I would share how easy it was. Lets Go Racing!

Bruce

JWQ500RC

My Feedback: (2)

Bruce

I'm ready let's go. Good luck with your TT40, down in Central Ca we are running ST40's, but are looking at starting a TT40 class. If your ever in the Central Ca area come race with us.

Jim

Tx_RcFlyer

My Feedback: (7)

Consider yourself lucky. Or maybe I'm unlucky.. I have two new TT Pro 40's and both of them were less than cooperative to get running correctly. I will say, after some tweaking, both engines are now rock solid reliable.

skull1971

be sure to take the carbs apart and clean them, they seem (or mine did) to have lint in the barrel just past the needle.

draftman1

Im with you in that Jim, I would like to adopt the RCPRO rules but I think for now, we should adopt the TT40 class. maybe later it will change. Im feeling alittle oposition also at our club. some want to keep all one engine, just to keep it even. but whats funny is, some of the planes are flat out faster than others. why? who knows. its the same engine, fuel and airframe. tinkering, prop tricks, unseen engine mods??? so what would be the difference of letting the TT and ST run together. unless one of them is quite a bit faster. there is alot of speed difference in an all one engine class anyway.

I wonder if we need to have a two club group meeting on racing?? maybe we can get it hammered out

GSJames

I only own one TT40 Pro so far, but when I took mine apart for it's initial cleaning, I found that the manufacturer had not machined the main port in the case all the way. It was over 50% blocked off with metal flashing because they didn't run the mill down far enough. I doubt if it would have even run. Very poor quality control, at least on that engine. If someone has an engine that really runs poorly, it may be due to bad machine work from the factory.

JWQ500RC

My Feedback: (2)

Andy

I think I'll come over for the Combat contest on Saturday with my brother so maybe we can find some time to talk about it then Talking to the guys in the Tulare club they seam to be OK with going to TT40 class.

PS Andy you know no one in our clubs with modify an engine.

Jim

ke6gkc

The club in my area will be startinc Club 40 in the spring. So I have only seen a few TT 40s run but what I have seen they run well.
I peaked mine out with an APC 9-6 on the bench at 16k I thought that was great for a sport engine. What is everybody else turning?

Bruce

BobHH

My Feedback: (18)

Guys, some of us are seeing upwards to 17K+ with the TT40. NOTE: WARNING!!! Please make sure to either replace or JB Weld the muffler bolt into place. Just heard from a buddy who was running in some new TT Pro 40s. Just as he was tweating one out with his tach in one hand the muffler bolt decided to break and go through the APC prop. He took a part of the prop blade in the leg but thankfully missed all other crucial areas. Said the prop is now about a 3-6!!! This is the 4th muffler bolt I've seen break.

Bob Harris

JWQ500RC

My Feedback: (2)

Don't have a TT40 yet, but my ST40 with MA 10X6 narrow is turnning about 15,700. This a old ST40 made in Italy that I used to run on a Quickie in the 90's. So far it still runs very good.

wrstew

My Feedback: (30)

I wonder if every person who owns, or has owned a ThunderTiger engine contacts them with an e-mail something like "as an ISO certified manufacturing facility, how can you in good conscience continue providing owners with a known weak muffler set up?" I wonder what the total price to a OEM would be to put a proper size, heat treat, and material to do the job correctly. Maybe 2 to 4 cents a unit? Would Dubb do it this way? Do we have a say so as end users? Lets bury them in e-mails till they do it right! A disclaimer doesn't fix a known problem, engineering does.

GSJames

Good Point. BE SURE to replace your muffler bolt with a piece of 4-40 all-thread and double nutted. I also secure mine with safety wire in case it does break, at least I can keep it on the airplane and out of the prop. I suspicion is that the aluminum muffler casting has a higher coefficient of thermal expansion than the hardened steel muffler through-bolt. The muffler just keeps expanding until it reaches the tensile strength of the bolt. The 4-40 all-thread is a relatively soft metal and can "stretch" with the expanding muffler.

Don B.H.

 I just got my first TT Pro 40 and cant wait to run in, I also just got my first  OS 25FX still in the box Don sent me a LA racer for the TT Pro 40  and Andy said he will send me a Coro Stang for the 25FX , Let it rip.

 Watch your 6
   Don B.H.
RCCA #957
RCPro#567

StanDouglas

The problem with the muffler bolt is an on going one. It is an expansion problem and users tend to over tighten the bolt which causes it to fail. Replacing it is a good idea. I use the magnum XLS 61 muffler bolt. Part # 120616 they're around $3.00. I bought several the last time I ordered.

Another potential problem is the coil spring in the carburetor. The black retaining screw for the barrel sometimes works loose and when it does the barrel comes out allowing the spring to be ingested into the crank shaft ruining the engine It goes from +16K to 0K in 1/2 revolution! The fix is to remove the spring. It makes no difference in the engine performance. The retaining screw should also be secured with Loctite. In a pinch I have added a rubber band around the carb so as to hold the barrel in should the screw fall out.

Rumors still persist about bearing failures, but of the 7 engines I have all but 1 have the original bearings and none have failed. On the 1 engine I replaced the bearings as an experiment with expensive precision bearings. I tacked the engine before and after and there was absolutely no detectable performance gain.

Finally, it's always a good idea to tear your engine partially down and look for fillings, machining errors etc. before the first run. Should you find a machining problem I wouldn't mess with it return it to your source. I have had good experiences with ACE Hobby, Inc. They replaced one of my engines that had a connecting rod fail during a race.

Stan D.

jerrysu29

You guys most be over torquing the muffler bolts or something. In 2006 I bought 12 TT40 Pros and 12 SMII's, never had a problem with any of these breaking muffler bolts or any of the muffler's coming loose. this problem may be caused by the use of the supplied gasket used between the muffler and the engine. I never use these gaskets,and the people that use the gaskets usually have problems
loosing the muffler,breaking bolts due to the muffler coming loose etc. ect. etc. Take it For what it's worth.
jerrysu29 Call Sign Wild Man

rbg

Here in the East we have been using the TT40 for years. The back bearing will explode on you. Alot of us replaced it with a better quality bearing and it solved the problem. Also 9X6 prop with a correct break in of engine will easily get 16,500 to 17, 000 with no problem

jerrysu29

Well out here in the old West We are running the Master Air Screw 10X6 at 14,000 to 15,000 with the TT40 Pro for the past three years and none have lost the original bearings due to high rpm Failure and with the 10X6 MAS they go faster. My question to you is WHY RUN THIS ENGINE AT SUCH HIGH RPM AND LOOSE THE ENGINE TO BEARING FAILURE, WHEN YOU COULD JUST GO TO A LITTLE BIGGER PROP GO FASTER AND NOT RUIN ENGINES ? jerrysu29 Call Sign Wild Man

sahartman21

I suspect a lot of the comments concerning running a 9 x 6 APC prop is in reference to using in 424 class Q-500 racing.

For that class of racing the props limited to on that prop due to rules. For the most part the rule is fair and the airplanes are all equal with that standard.

For me the standard TT bearings work fine until the engine goes through a crash. After the crash the bearings have gone out on 2 of my engines. [] The bearings don't seem to go out before then.

jerrysu29

Any side loading Impact to a roller bearing will definitely cause dents in the bearing races, leading to bearing failure. I would think this is an Item that should be checked after a crash ? Loosing the bearings while in flight after the fact, results in scoring of the liner and piston and sometimes the lose of the complete engine. As far as 424 Q 500 Out here in the old Western Dakota Territory we just make up our own club rules TT40 stock and a 10X6 MAS Prop and go have fun.
jerrysu29 Call Sign Wild Man