gkamysz

My Feedback: (19)

It's a design error. But somebody other than customers should have determined it was a problem.

tipstall 131

Hi guys,

So besides the oil passage problem on the .75 (which seems to be an easy fix), is this engine any good. I am looking for a 4 stroke engine for a scale project and I was looking at this one. The price seems to be good. Is it worth while?

Pippin

I would rather get an O.S. 56a, Saito 62 or Enya 53.

According to a review the TT75S is cheaply made. Look at the cylinder head and the valves. Notice there is no special inlet. Also, you will find sintered bearing where other brands use ball-bearings. Costs of production and material is low, so is the price. In the end, it's your choice.

BarryReade

My Feedback: (1)

The TT75s is a great motor for the price.  Mine runs very well and I feel I got a good value for my money.  I made my mod for the oil passage in the rear brg. and got over it.  I only have about 5 hrs of run time on it and am getting ready to check the valve lash.  The carburetor idles very well, infact most of my club members are amazed at how well it runs.

tipstall 131

I'll go and look for one at a hobby shop. If it has no "real" issues such as wear problems or reliability problems, then I suppose it should work. The other brands are a little bit too expensive here.

estradajae

My only contra against the TT F-75S is the sealed rear bearing....

THe engine runs very good and quite powerfull for its size. It is smaller than the other 70s and lighter.

Bronze bushings donĀ“t think that they are bad doing their job.

What do you mean that there is no special inlet?

The cylinder is not from bare steel...it is plated steel, the machine work on the piston is nice too, the piston is lightweight and carefully design.... A bigger intake valve... I donĀ“t think the engine is cheaply and bad designed overall, apart from the cam lube problem.

The carb is also nice made and works very good too.

BarryReade

My Feedback: (1)

What E said.

How are you doing E.  Is your motor holding up well?

estradajae

Not yet....It is currently on the box because I haven't had enought time to repair the plane....I had to take the covering off...and I'm Trying to cover it with cloth since I want to paint it like a real SU-31 hehe.

IĀ“ll post the results when the engine is back in service, I put a shielded bearing on the back and a sealed on the front...

BarryReade

My Feedback: (1)

[quote]ORIGINAL: estradajae

Not yet....It is currently on the box because I haven't had enought time to repair the plane....I had to take the covering off...and I'm Trying to cover it with cloth since I want to paint it like a real SU-31 hehe.

I´ll post the results when the engine is back in service, I put a shielded bearing on the back and a sealed on the front... [/quot

I wonder if you will have to place a small hole in the seal to have lube flow through the brg? I am very happy with the original fix of putting a 1 mm hole in the seal. I hope it works for you.

Pippin

estradajae,
The valves are just placed into the aluminum head. Other brands use a special inlet for tightness. The expensive solution:
http://www.rcplanet.com/PhotoDetails...de=OSM46204020

I still have my 75s in use. I paid around Ā£140 if I remember correctly. Right, a similar powerful Saito, Enya or O.S. would cost another Ā£50 or Ā£60, depending on the market.

The 75S seems to be "right-priced".

Has anyone run the engine around 12K? How about using an APC 11x7?

BarryReade

My Feedback: (1)

I am running an APC 12X8 on 30% Heli fuel and taching 10.5K rpm on the ground.

gkamysz

My Feedback: (19)

Bronze valve seats and guides are going to be a thing of the past in model engines. OS Alpha Series 56, 72, 81, 110, and FL-70 and FS-200 do not have bronze inserts.

Pippin

Oh. Not even O.S. anymore?

I clocked a MA K 13x6 today. Just 9200rpm (Cruel Power 5%). MA Scimitar 12x7 10.200rpm. Do i need more nitro?

estradajae

FĆ¼r mich Cool power 5% funktioniert nicht..ich war auf dem SchwƤbischen Alb.... dan habe ich mein eigenes Sprit gemischt mit 15% Molsyn, 3% Rizinus, 10% Nitro und den Rest Methanol... hat immer super funktioniert... du kannst alles von www.spritonline.de bestellen...schnell und einfach wenn du Methanol besorgen kannst (die Schicken methanol oder gemischte sprit nicht billig)... Du kƶnntest vielleicht cool power plus eine kleine dose (200ml) Rizinus mischen....geht auch gut...oder mischen Graupner sprit (Mit rizinus) und Coolpower...


For me cool power 5% never worked good, I couldnĀ“t set the idle and seemed that the engine didnĀ“t like it...so I went on my own fuel....basically the omega 10% percentages...15% Molsyn Synthetic, 3% castor oil, 10% Nitro and the rest methanol...it worked very good all the time..

I really miss the Molsyn oil, an oil that didnĀ“t dry, covered all the parts nicely and didnĀ“t gum up.

At that time when I was in Germany I didnĀ“t had a tacho, but it was surely about 9600 with the graupner 13x6 wide blade...and I also used a Sonic 13x7 and it was the best prop ever for the engine.

Pippin

I tried Technopower with the same results:
http://www.jperkinsdistribution.co.u...s&Navmain=Fuel

BarryReade

My Feedback: (1)

I have found that 4 strokes like a lot bof nitro compared to 2 strokes.  The fact that 4 strokes only give about half the power boost for a given nitro percentage compared to a 2 stroke makes the 30% Heli fuel (has extra oil that the 4 strokes like) perform like 15% in a 2 stroke.  Anyway, being a lazy git, and having mixed my own fuel in the past, I feel mixing your own fuel gives you a better product than the commercial blends.

twostroke

My Feedback: (6)

Has anyone heard anymore on the cam lube issue with these engines?

BarryReade

My Feedback: (1)

I haven't.

If I get another TT75s I will mod it like my current one and enjoy the heck out of it.  I just overhauled an OS 91 and it had bad main brgs, cam, lifters, and a very slight scored piston.  Replaced the brgs, cam, lifters, and polished the piston with 1000 gr. paper.  It runs great.  The guy who sold it to him said it was running great.

Pippin

I've run a couple of gallons trough mine yet and no issue with the cam bearings. In fact, somehow oil gets through the front bearing during running. The front bearing is not sealed.

The only problem so far has been a gridlocked piston ring but after cleaning the ring and piston everything is fine.

twostroke

My Feedback: (6)

im going to order on and remove the seals on the bearing and install a rubber sealed bearing on the front bearing that should fix any lube issues.

estradajae

I havenĀ“t run my engine (I changed the rear bearing with a shielded and the front with a sealed) in quite a while...I havenĀ“t finished my covering job on the Su-31...Hope I have the plane finished soon since IĀ“ve been working hard and had no time for planes!! =(

estradajae

HI everyone...


Last week I finishedthe works on my SU-31 and put the plane back together...

This time I installed the engine inverted...and man!!! it was like a dream!!!

Engine was turning 10K a scimitar 13x6 with 10% Omega!, very nice!!....

Unfortunately...after a stall turn I lost control of the plane =(....gotta build a new set of wings =(.....

Pippin

Sorry to hear.

I tried Scimitars on an O.S. Alpha but switched back to K-series.

Valius

Hi TT75s owners!
The last post was 3 years ago, I'd like to know some good news about TT75s. What about new ones? Did Thunder tiger manufector still solve oil likage problem?[>:]

sport10

I would like to hear if TT fixed the lube problem also. Thinking about purchasing this motor too.