XJet

How do you find the TT54FS?

I'm thinking of getting one for a 40-46-sized LongEZ ARF and was wondering what the power output's like. I don't want to underpower this bird because I hear they can be a bit of a handful if you don't have enough -- but I'd rather use a 4-stroke than a 2-stroke.

markisenberger

I bought a TT .54, which barely gets my Extra 300 .46 off the ground. Consider yourself lucky if you never found one. I might be doing something wrong, but I have tried every prop combo possible, and don't get anywhere near the company claimed RPM range; furthermore, the most effective actual flight was with a large diameter low pitch prop outside of the recommended range.

You get what you pay for as they say...

markisenberger

And one more thing, Obelix1, I can relate to the prop throwing... It took two trips to the flying field, and one to the hobby shop, before it was properly tuned. It was throwing props relentlessly. I heard every possible explanation, but according to the manual, and my experience, it's when you run the motor too lean and/or have too large of a prop... However, the adjustment differential between prop throwing and just right is tiny, less than 1/8 of a turn....

In case you can't tell, I'm REALLY down on this motor...

Sport_Pilot

Ace hobby probably put the cam in wrong. I don't own that engine, but if you go to http://www.acehobby.com or http://www.thundertiger4u.com you can download the manual.

Edge3644

Hi,
Thunder Tigre 2-strokes are perfect, but 4-strokes are rather useless. Those poor Tywanese/soon Chinese model engine design almost engineers tend to fergot the basic mettalurgy principles. As the result the only reliable parts in their designs are crankcases, bolts and nuts and presentation boxes. The rest, that basically we pay for will break sooner or later.

Sport_Pilot

The same engineer who designed the first OS Surpass designed the TT four strokes. You need to actually use one before you spout useless opinion.

XJet

I agree, my TT91FS is an excellent engine. It has more power than my Saito 100, but heavier.

It hauls a P51 Mustang around as fast as an ST90 -- and it's already clocked up a few hours -- getting stronger after every gallon!

DarZeelon

It begins with the weird break-in procedure TT specifies, reportedly telling you to run the engine at less than 5,000 RPM for the entire first tank... Achieving nothing flat, except throughly glazing the cylinder... which then requires that about three gallons of fuel be run through the engine, to break this glaze and have the engine brought up to par performance...

[link=http://www.lycoming.textron.com/main.jsp?bodyPage=/support/publications/keyReprints/operation/engineBreakIn.html]This[/link] is how it should be done, but make sure first the ring is properly gapped, so the engine will not seize under the heat load.

...It continues with the choke mechanism, which is a part of the intake tract and which the engine cannot properly function without, which is innocently removed by many modelers, in an effort to gain some performance...


I would not know what I should expect from a four-stroke engine made by this manufacturer...

Harry Lagman

This is Saito's recommended run in procedure. Are you sure you're not confusing theirs with TT's?

DarZeelon

Grant,


Although this was quoted in previous threads as the TT procedure, it is what the Saito manual and Saito-Engines.info say...

I corrected my previous post to reflect the actual statement in the TT manual.

NM2K

My Feedback: (14)

My experience at www.thundertiger4u.com has been good. Fixing a much needed problem in availability and parts support.

All of my Thunder Tiger engines have been two-stroke. None have been problematic.

I remember the carb problems with the early TT four-stroke .91. Too bad it is so heavy. Of course, in many applications, the little extra weight is irrelevant.

Sport_Pilot

Dar,
Bax settled this argument some time ago. You cannot apply apply a full scale aircraft engine breakin proceedure to glow and expect good results. For one the carbon (ie, glaze ) for glow engines comes mostly from the castor varnish, as well as the fuel. That is why rich breakins with castor oil fuel breaks in quicker. The full scale aircraft is depending on oil from the crankcase and so full power high revs sling oil onto the cylinders. Both do better with full speed runs, but our glow engines need more oil and a rich mixture to stay cool. The low speed operation recommended by TT is not a full tank but 5 minutes, then full power is applied. The recommended break in prop is a 11-10 which lets the engine rev and provides plenty of cooling air.

http://www.acehobby.com/ace/PDF/Engine/F_91s.pdf

Harry Lagman

While we are on the subject of TT .91 Four-strokes, I have to relate my observation of the single example I have set up for one of the guys.

I don't know if all TT .91s can be judged by the engine I worked on but this engine was one of the sweetest running four-strokes I have seen, right from the second tank. It had a rock solid 2000 rpm idle and transitioned perfectly. When new, it pulled 9800 rpm with an APC 13x8 prop - right on par with its non supercharged contemporaries. With time it probably would have improved on that. This one was running on 10% nitro.

Fuel efficiency seemed to be comparable to an OS .91 and far superior to a Saito 100.

This TT .91 was most definitely an engine one could fall in love with...

DarZeelon

Hugh,


The lubrication of the cylinder walls in full-size airplane engines is achieved with hollow con-rods and spring-loaded 'oil-injectors' in them.
No need for slinging any sump-oil.

The need for high loads is because high combustion pressures get behind the top ring, in its groove, pressing it with strong force (the 'springiness' of the ring is a minuscule, negligible force) against the cross-hatched cylinder walls. This causes mutual honing of the two parts, for a perfect seal and fit.

Low combustion forces allow a glaze to form instead and prevent sealing and actual break-in.


Allowing the engine to run at high RPM, by using a light prop, would lower the combustion pressure and slowing the break-in process; not speeding it up...

Sport_Pilot

They don't sling sump oil! They sling it from the aforementioned "oil injectors" smaller and simpler engines sling from a hole in the con rod upper journal, as well as oil that sprays out of the con and main journals. Even the simple O 200 has a bladder shaped oil sump that prevents oil from being slung directly from the sump. But even the "oil injected" engines sling (spray?) more oil at a high rate of speed.

I am not arguing that point, but our engines will overheat if we push this to the max, and any engine will eventually break in at lower power settings.

Wrong. The glaze is carbon which bonds with the metal and fills the pores and scratch's in the metal, except for the deeper cross hatching. This is not to be confused with the mirror finish glaze which forms later with much wear. The latter is simply the metal polishing each other as it wears.

Now I am recalling this from research and other comments from the last time we had this arguement so I may or may not have this exactly right. I think Bill Roberson and Bax settled this.

High RPM is a plus because we cannoth allow our engines to overheat thus not fully loaded. The extra friction from high RPM also helps seat the rings. Also the internal pressure is only lower by the amount of reduced volumetric efficiency. If the engine is supercharged to maintain 100% VE then it will have about the same internal pressure at high RPM as low. Because of our lubrication system and fuel we cannot seat rings as quickly as a gas engine, and we cannot afford to overheat them.

wcmorrison

My Feedback: (2)

Is that why Poloroid went bankrupt and Kodak is still around? I recall the Kodak instant camera, it was not very good at that. Patents do count, but there are still those that cheat. A lot get caught and many get sued. But I doubt that engines are directly copied, and there is only so much you can do to a 2C engine. I think the difference is in the manufacturing processes, some are better than others, more durable, etc..

Cheers,

Chip

Sport_Pilot

I think the only model engine's with patents are the RCV and Ericson. I know of no patents on any of the major brands of glow engines, except possibly the OS Wankle, and I bet that has expired. As I said before OS and Enya copied American manufactures when they started, so if they are copied then they are getting their just desserts.

Flyboy Dave

My Feedback: (21)

DarZeelon ....you have the right idea.

How much oil is in the fuel of the Lycoming engine ?...none.

What has Lycoming done to prevent oil from getting to the compression rings ?
....they have provided oil control rings, or "scrapers"....they don't want any
oil getting to the rings other than the minuscule amount left behind from the scrapers.

What is produced when fuel and oil burn ?....carbon.

What is glaze on the cylinder wall ?....carbon.

Why do we want to prevent glaze (carbon) build up on the cylinder wall, at any time ?
....glaze prevents the ring from sealing, resulting in loss of power (from loss of compression),
blow-by, plug fouling, and excessive oil consumption.

I read here on RCU once about a Guy who stated it took 3 gallons of fuel before he could
get his engine to idle.........I wonder why ? [sm=stupid.gif]

FBD.

Sport_Pilot

Excessive glazing is indeed bad, but the right amount speeds up the break in. The best running engines I have seen had a very shiny glaze when torn down, I don't care what Lycombing says glaze is good, but to much too soon makes the walls too slick for unseated rings to seat. And again there is a big differance in the glaze in full scale engine and our model engines. The glaze formed from castor oils is varnish and does not bond with the metal right away.
In fact I doubt the carbon ever bonds and becomes part of the metal in the way it does in full scale. I suspect the cylinder wall temperature does not get above 600 degrees or so which I think is the minimum.

In short you cannot compare the break in of a model engine with a full scale aircraft engine.

Sport_Pilot

I Dave,
You obviously don't know that OS, Enya, and others were stealing design features and even entire engines long before TT did. They copied Fox, Veco, and others. You say TT copies OS then act as though Magnum is better about this. Well most of the TT engines are not copies but do share some features. The TT .46 has some OS SF features not FX, but then the designer designed both the SF series and the TT Pro engines. The TT four strokes share the OS cam drive features, but have angled valves similar to Saito. They also have a different combustion chamber design.

However your wonderfull Magnums are almost exact copies of OS engines. Come to think of it Magnum doesn't even make an engine. It is just a Hobby People brand name.

Dauntae

I guess this thread would be the best place to ask this question for my TT 91, It was recieved in a auction plane but the venturi was missing and in another thread someone said to make an adapter with the same size hole for the carb as my Magnum has so I went to work and made my own venturi but have yet to even test the engine. but I also wondered if you guys would think it will help it or should I just keep searching for a factory choke assembly if I can ever find one. I have a few links given to me I've yet to try. Unfortunatly every time I have free time it's been raining or freezing out so this engine might have to wait for spring.

Dauntae

DarZeelon

Bruce,


Take a look at this [link=http://www.acehobby.com/ace/TTR9801.htm]Ace Hobby page[/link].

I am sure they can supply the part, or refer you to someone that can.
...But make sure your jaw doesn't hit the floor, when you hear the price...

Maybe I am wrong about this, but it is routed in the price that was quoted for the TT .46Pro P+L set...

speedster 1919

My Feedback: (3)

The Kodak and Polaroid example is way off the mark. Your talking about 2 American companies doing business in america. We enforce all patents. I'm talking about a China company copying a Japan company to sell to the USA. USA is the largest market in the world. It has been said if you had all of Europe business it would only be 1/12 th of the US. I deal with Body shop tools and the cheap stuff makes sure not to copy an American design. You easily get around patents by adding extra holes and number of bolts and fins , etc. I'm sure China doesn't honor any WORLD PATENTS , We don't need no stinking patents.........

Dauntae

Thanks DarZeelon, w8ye also gave me another source too but I don't even know if there is life left in this engine so I will try to run it this weekend to see if it's worth the investment before ordering parts, I had some time at work so I made the vevtury to try. I actually got the engine in a Pica Waco with everything but the TX for $125 so if it does run than I got a cheap engine with a free plane LOL Thanks for the link and if someone has a picture of the choke I'm missing I might be able to make one up but I have no idea what it looks like. Never seen a TT 4 stroke up close before I got this one.

Thanks again
Dauntae
OH and Dar... Don't let my real name get out LOL

Sport_Pilot

You are talking about engines without patents, anywhere. So there is not legal issue with copying the engine down to the last detail. Unless you also copy the trademark, but that is a copy right violation not a patent issue. So if not patent then there are no issues with copying a design. Extra holes and number of fins will not get around a patent. If for example you have a patent for a rotary type engine that uses a unique rotor, then adding a hole or two or changing the number of fins will not allow the company to produce an engine with that patented rotor.

I think you are confused about what patents are. They are not issued for every product. In fact I would estimate that 99% of all products have no patents, and I suspect that is also true of most of your body shop tools.

BTW if someone imports a product from China that violates that patent, then both the Chinese company and the importer can be sued for importing that product. If the courts find in favor of the patent holder the importer and/or the company will have to pay a huge lump sum payment for royalties of products produced before the settlement , and a royalty on future products, or the patent holder prefers, the court can ban the sale of that product in this country. The fact that OS and/or Hobbico does not sue, is because there are no patents on the OS engines that are copied.