hsukaria

The 45ABC is more powerful than the 51 ring? That's a twist!

1QwkSport2.5r

It's pretty normal for a tapered bore engine to outrun a ringed engine. The stronger the piston seal is the better the engine performs. Listen to the "pop" of the transfers opening on an ABC and then the ringed. You will notice a better pop from the ABC. Even Bowman rings have significant leakage past the ring. Turn a ringed engine over real slow with the plug in and compare to an ABC or ABN engine. The latter will rarely (if in good running order) if ever have any leakage past the piston once the exhaust port is closed.


Real high performance engines will be tapered bore, ABC or AAC. ABN will rarely have the pinch that an ABC or AAC, perhaps the nickel can't handle it?

hsukaria

There are very strong apinions regarding ABN engines. The only nickel engine I have is an OS 55AX, wnich is nickel, but ABL instead of ABN. I am no expert, but I suspect OS worked out a way around the nickel weakness.

1QwkSport2.5r

Nickel plating is a cheaper alternative to chrome. The piston/liner fit is much much looser in an ABN than a true ABC/AAC. Why do you think OS engines break in so fast? Thunder Tiger is not a lot different except their liners don't peel.

OS' ABL process is still nickel plated. Aluminum piston Bimetalic Liner. Nickel plated brass is bimetallic.

A TT ABN will outlast an OS ABL. That's a strong opinion many share. I'm not knocking it though. I have a TT ,46 that had zero pinch when new but runs like crazy. I also have an OS .10FP ABN. Runs fine, but again no pinch.

Hobbsy

My Feedback: (102)

There is a sort of humorous story behind the ST .45 ABC. I bought it used and when I first fired it up, (that's a stretch), it would only turn 4,500 rpm and would only start with a starter at full throttle. A little peak in the exhaust showed the problem. The sleeve was turned about 45 degrees CW when viewed from the top. In 5 minutes or less it ran like a top.

The 45 most likely has much less time on it than the .51. My former son in law gave the .51 after it had powered a Sport 500 helicopter from Hobby Lobby for about a year. The .51 originally had one of those loud bullet mufflers or whatever they were called..The .51 flew in many planes in the 90s on Fox 5% fuel with 20% castor. It also flew a Kombat Copter a few times.

hsukaria

My G51 is the most used engine I have. It is so dependable. A few years ago (about 6), I crashed the plane it was in into a flooded river bank. The plane was totalled, but the engine was under water. I took it home and promptly soaked it in ARO. It sat for a year without a plane, then I installed a new ring thinking that the water might have damaged something (in retrospect, I don't think it needed it). I have been flying it ever since. It got better throttle response when you guys told me to switch to 5% nitro from 15%. I liked it even more after that. It is again without a plane because I installed an old Irvine 40 into the Escapade 40.

mike31

My Feedback: (67)

I have no problems wit any Super Tigre engine 40 through 4500!

1QwkSport2.5r

I've now got 4 Super Tigres. I added a G20/2300 to my collection. I've no clue what I will do with this 2300. It has maybe 1 gallon worth of time in it and was turning a 16x6 APC. I've seen it running and other than the previous owner using 15% fuel in it, it's in good working order. Ring is bedded in, compression is good. Right now I only have one of my ST's on something, an S90K. Still working the bugs out of some icky vibrations and getting it on the pipe. No BS, Tigres need lots of run time before they become a "clockwork" engine. Of my ST's, the S29 was the least temperamental (on a full wave pipe even!) and the S90K took about 3 gallons to throttle nice and idle low.

hsukaria

About the only misgiving I have about the larger glow engines 60/75/90 is the glow fuel consumption. Not just Super Tigre, but all glows. I am greatly enjoying the smaller glows, and the larger gassers. But the larger glows I will use them less frequently only because the fuel cost adds up pretty quick. I know a guy at our club who has a ST90 and ST75 (don't exact model/vintage), but he ended up switching from the ST90 to ST75 just to save a bit of fuel. I also noticed that even going from a 90 I have to a 74 gives noticeable fuel economy.

1QwkSport2.5r

No doubt bigger engines use more fuel. I thought the "rule" was 1oz/min at WOT per 1 C.I of displacement or thereabouts. It's easy to burn a gallon a day with big engines. Mixing your own fuel can greatly reduce your costs, but at the expense of buying the chemicals up front. 5/20 fuel all castor costs me less than $10 a gallon. My hobby shops are selling fuel for $28-$34/gallon depending on brand and nitro content. Gotta love this hazmat fees...

When I was breaking in my Jett .35 I was going through 7oz of fuel in about 4 1/2 minutes. After break-in its running about 8 minutes on 6oz of fuel. The Jett sucks almost as much fuel as my S90K does. Seems obnoxious but it's too much fun to care. LoL

hsukaria

I am lucky in that my LHS still sells glow fuel at reasonable prices. Plus I can buy it by the case at good discount at the Toledo Show in the Spring. That plus the fact that I use only 5% nitro on my 2-strokes(especially the Super Tigre and Fox). I splurge on my 4-strokes and run 20/20 fuel. But then, 4-strokes are more economical.

jeffie8696

If you could make a bulk buy with some club members you could save a lot on fuel.

hsukaria

Our club used to do that before I joined. We can't seem to get agreement between us on brands and grades. But it would be a good thing to bring up at our next meeting.

1QwkSport2.5r

I don't belong to a club, and even if I did I probably wouldn't use their fuel anyway. Most guys around here use 15/18 fuel and most of my engines need 0-5% nitro and I like to use 20-25% oil depending on the engine. I avoid synthetic oil too, and most commercial fuel is mostly synthetic.

Hobbsy

My Feedback: (102)

1QS, I may have proven what you say about the 5% fuel, I just ran my ST 3000 mostly to set up a Cline regulator on it. I ran WildCat 15% fuel with 18% 80/20 blend. Really wrong for the 3000, the plug is a Taipan idle bar..Has a fairly new Frank Bowman ring, approx one hour and excellent compression. The engine is turning a perfectly smooth and quiet 4,500 in the picture. Above 4,500 it begins to rattle and at 6,600 it really rattles. Sounds as if it's hurting itself. From what I've found searching around 7,200 is easy with 5% fuel. I'll have to get some. Sorry about sun problem.

Fuel===WC 15 with 18% lube
Prop Mejzlick====18x8
Max rpm========6,600

Muffler===Davis Diesel SoundMaster

AMB

Hobbsy sounds like way too much nitro for the compression, bet it would run on diesel also martin

1QwkSport2.5r

Super Tigres do not like a lot of nitro, China or Italian doesn't matter. None of my ST engines like idle bar plugs. 5% nitro 20% castor and McCoy MC59 plugs = ST happiness.

An Enya 60-4C will run on diesel with a CR of about 7.31:1. I'm sure a ST will too.

AMB

will the Enya 4 cycle continue to run on diesel if plug power removed, interesting on 7-3.1 compression ratio regards martin

1QwkSport2.5r

Someone had mentioned they ran a 60-4C on diesel without glow plug being lit. I'll try to find that post later.

The fuel could be catered to the lower CR by adding more ether. It would run cooler on more ether too.

If I had access to make diesel fuel, I'd try it in my R120-4C as it's got a higher CR than the .60.

erik58

My Feedback: (4)

Just got a st3000 and I would like to know what fuel to run it on. Im going to eventually going to turn it to dieseI have to break it in first and find a head for it. Thanks Erik

1QwkSport2.5r

If it were me, I'd be running it on 18-20% oil sloppy pig rich like I do all my ringed engines, and once its had a gallon or two through it on the test stand, drop the oil to about 10-12%. The big ST's run really burbly in the midrange if you use too much oil. The 2000, 2300, and I believe the 2500 all need 18% oil minimum ALL the time. The rest of the big ST's run less oil.

flyingagin

+1on the break in and then running oil amounts 1QwkSport2

I had a electronic glow assist on mine and still it would not run or transition worth a darn till I dropped the oil content to 11%. And then it was real sweet heart; just like that. I removed the assist and it ran just as good.

Ken

Hobbsy

My Feedback: (102)

I actually have a Davis Diesel head already. I'm just breaking the new Bowman ring in and will put DD head back on. I know the fuel is all wrong but its all I have and it will serve to get the ring run in as long as I stay below 5,000. The idle bar plug will work for the running in process. I could put a cold plug in it but don't want to keep the glow battery on it.

1QwkSport2.5r

As long as you're running it at least 1000rpm rich of peak, the high nitro isn't a big deal. I ran some 15% nitro in the G51 I have during break-in, but I wouldn't do it afterward.

As for the big Tigres and fuel - most places don't make big ST fuel anymore, last I had seen was Powermaster 10/10. Not sure if they still make it or not, and IMHO 10% nitro is too much anyway. I'd take some 20/20 fuel, mix it with straight methanol and add a little oil to get to 5/10 or thereabouts.

OR have a fuel company make a custom mix for you. Some places will do this.

Hobbsy

My Feedback: (102)

If RedMax is still around they will do it, I'll have to see, but it wouldn't pay me to get their fuel since both my 3000 and 4500 are going to be conversions. My 2300, .90, .51 and .45 already are.

PS, even with two head gaskets the 15% was too much.