dmajchrzak

My Feedback: (17)

I'm picking up a Jamara F4U Corsair .61-.91

I usually lean toward the larger end of the power spectrum..

What do you recommend in a good 70-90 two-stroke engine?

I know ABC engines well, is there any reason to go ringed?

If TT would sell a .91 2-stroke I'd be all set. I'd prefer not to pay the extra $$ for the O.S.

Magnum XLS-91?
Enya 80?
GMS 76?
Tiger Shark 75?
Irvine 72?

Thanks for your input.

logger

I HAVE A ASP 80 4 STROKE FOUR SALE. LIKE NEW .

Hobbsy

My Feedback: (102)

The Irvine .72 you mentioned is an excellent engine, I've had a Q .72 for several years. I can't speak about any of the Chinese engines, never had one. Also there is a Webra .80 that is very strong.

w8ye

My Feedback: (16)

I have a couple of the Super Tiger G90's. They are nice engines. They are the same size as a ST 61.

Jim

ShempHoward

My Feedback: (3)

Once you go above a 60 size 2 stroke glow nearly all of the engines are ringed and not ABC. Jett makes a 90 2 stroke AAC but large 2 stroke ABC types are often hard to start given their high compression relative to a ringed engine which is why most engines over 60 size are ringed which have less compression when cold.

The Irvine 72 is a well made engine that you won't regret buying.

fiery

My Feedback: (2)

If power and reliability in a 61 case are the criteria, without breaking the bank, take a close look at ...

MVVS .91, with a bisson pitts muffler. That would be my choice (the Irvine 72 is nice too).

to check it out, go to:

www.justengines.unseen.org/mv91.htm




fiery

dmajchrzak

My Feedback: (17)

Any info on the new Magnum XLS-91A? Seems to be what I'm looking for ... dual needle, ABC, 2-stroke.....

jaka

Hi there!
MVVS has both .91 , 1,20 and 1,50 ABC engines and they are very easy to start, both cold and warm. ABC, AAC or ABN engines are NOT harder to start than ringed engines......!
You can buy MVVS engines and spares at this site: http://hem.passagen.se/airracing

Volfy

My Feedback: (23)

Dave, I have an ASP .75 stroke, which is identical to the Magnum engines and it runs very good. Lighter than my ST G75 and put it to shame in terms of power output.

The Magnum/ASP are obviously not OS-class engines, but if budget is one major consideration, they are a good choice. Just Engines has the ASP 1.08 on sale right now. It weights exactly the same as the .91 and you can buy a BCM Pitts mufler for some US$30 more, together costing no more than what you'd pay for the nearly identical Magnum XLS91A. Not a bad deal for bang for the buck.

Irvines are very nice. The Jetstream carbs are superb. I would buy one if I don't already have 2 .75s. Too bad they don't make a .91 class engine.

Enyas are great engines that are comparable to OS quality, with prices to match.

The GMS 76 is another good budget choice. AFAIK, it is the only ringed available .75-class 2stroke since the new ST G75 is not available yet.

w8ye

My Feedback: (16)

The new Magnum XLS series 91A looks more like a OS 91 FX around the fin and head area. But around the mounting lugs I understand it's more like a OS 120 four stroke. I have an ASP 108 red head which is older. It runs nice, starts easy, and was easy to adjust. It doesn't have any more, if as much, power as my ST 90's. The mounting lugs on my 108 are the same as a 120.

Enjoy,

Jim

ShempHoward

My Feedback: (3)

Jaka; The info I repeated concerning ringed vs. ABC came straight from a question I asked many years ago on RCO where it was answered by none other than George "Nobler" Aldrich who ranks right up there with Clarence Lee as being a virtual "engine god" in RC flying. But any one in the hobby, even a rank beginner, can simply feel the compression an ABC engine makes when new compared to a ringed engine of the same size.
George commented that there wee not many ABC 2 stroke glow engines once you got over the 60 size since the compression these engines usually have makes them more difficult to turn over and start. I think many on RCU knew of "Nobler" and what he said could always be taken to the bank - period.

The website you listed is in Swedish or some other language I could not decipher to in fact see if the big MVVS engines are not ringed as you say.

Hobbsy

My Feedback: (102)

I concur with Shemp and Nobler, I have two Fox Eagle .74s, one ringed and the other ABC. I converted the ABC one to Diesel and even with the compression screw backed out all the way it had entirely too much compression, so I moved the Davis Diesel head to the ringed one and it worked perfectly with the compression screw ending up about the center of its travel.

Dazzler

My Feedback: (6)

I would go with the OS91 FX 1st, then the Irvine 72, thats it. I wouldnt buy any of the others you have listed. Daz...

Volfy

My Feedback: (23)

Well, big ABC engines may not be any harder to start after you break it in, but brand new out of the box they can be a bear.

Now that my Magnum XL1.08A is fully broken in, it turns over nicely and I can easily start it with a cheapo Tower starter. However, new out of the box it was so tight it creaked going over TDC like a duck being slaughtered. I had to buy a Sullivan Dynatron and put it on 24V to start the sucker.

This is why .91 - 1.08 is the upper limit nearly all manufacturer would built ABC engines. The 1.20 and 1.44 MVVS 2strokes are twins, so the individual cylinders are really .60 and .72 respectively - well within the practical limit of ABC engine size.

ShempHoward

My Feedback: (3)

Volfy - Isn't the Magnum 108 a ringed engine?

w8ye

My Feedback: (16)

Mine is ABC

jaka

Shemphoward, I have been into modelflying for many years so I respect both Clearence Lee and George Aldrich and Peter Chinn for what they know, I have read their articles in RCM and ModelAirplaneNews from the day I began flying R/C models in 1975. And I regret the passing of George Aldrich a few month ago.
I built his Nobler 25 years ago when I was into CL-flying it was a Top-Flite kit from the early sixties found on a swapmeet.
As for ABC engines contra ringed engines....I agree tha a ringed engine has somewhat less compression when you turn it over by hand ...but that doesnīt mean it is harder to start by hand!
When K&B intruduced their .40 pylonracing racing engines in the middle of the nineteen seventies they were real hard to turn over by hand, they squeeked and recquired a engine starter to really get going......but we have had come a long way since then!
Todays modern sport ABC engines ( OS, Irvine, Webra, ASP, MVVS, Magnum, Super-Tigre to name a few) are real nice to just flip start! As for the MVVS line of engines, all 2,0cc-25cc are all ABC engines ( except the 2,5cc ( .15) diesel which has a cast iron piston running in a steel cylinder, and they are easy to start by hand. Though I do not recommend hand starting an engine because of the danger involved, I think itīs a god way to realy "know your engine"! But keep the fingers away......

I donīt know how you do, but I always ( try too at least) flipstart my new engines the first time I start them!
I always flip start my MVVS 25cc ( 1.50) singel ABC when I fly my SIG CAP 231 EX, and it starts on the first or second flip everytime! Naturally I would use my Sullivan starter if I could but the engine is just to big.... so I flip start it. Even if that big MVVS would have been a ringed engine I think it would have been difficult for my starter to cope with it.
I have been importing MVVS engines to Sweden the last 10 years
so if you want to order MVVS engines, spares, get advise help ...feel free to contact me at my website: http://hem.passagen.se/airracing
or contact me by email: [email protected]
I will make an English translation as soon as possible.

Regards!
Jan K

Volfy

My Feedback: (23)

Shemp, the Magnum XL1.08A is an ABC engine. It runs strong and reliably. The only thing I can find fault with it is that because they put a huge carb on it for great top end power, throttle response is not very linear -easily fixed with throttle curve mixing on my Futab 9C.

The one I have belongs to the current or previous generation depending on how you look at it. The bolt spacing is 34mm. Just Engines is already selling the newer 1.08 under the ASP brand name, which has 42mm muffler bolt spacing. It seems that Magnum/ASP is standardizing on this bolt spacing for the .75-1.20 2stroke. The Magnum XLS series belong to this new generation.

Curiously, Magnum does not currently have a .75 2stroke. I bet when they do come out with one, it'll be identical to the ASP .75 I have.

Planeboy P51

I think when you're looking for a 91 2-stroke, you should get one that's the same physical size as a 60. If you're planning on a magnum 91, might as well get the 108, same size, same weight I think without the muffler. In my experience, don't get a magnum or anything of that variety. Generally not as powerful or as user friendly as an OS. Don't even say that your Magnum paperweight 91 will equal my FX (maybe their new series is better than the last...). If you don't want the OS, get the MVVS. Or, if the supertigre is really the same size as their 60, get that. When you get into motors this size, and your bird is more than "a couple hundred" dollars, don't pick up the cheapest motor possible. Sometimes you may do fine, but penny pinchers often end up spending more than the one's who "splurge" on the good stuff...

Ed_Moorman

My Feedback: (1)

I have had both my OS .91FX and my Magnum 1.08 (ABC) in my Joss Stick. I really count reliability and smooth running above anything else, but in this case, the same engine has both reliability and power.

The Magnum 1.08 with a 16-6 prop is the better engine. My Mag starts by hand in usually 1 backwards flip. I have never touched it with an electric starter. I have it set to leave a slight smoke trail in flight and it runs great all through the tank, although my neck wears our in 10 minutes.

My OS .91FX (ringed with a 14-6) needs an electric starter. It never has run very well in the air which is the reason I took it off the Joss. I recently picked up a K&B .61 remote needle valve assembly which is supposed to stop the air leak around the banjo area. Yes, I have tried silicone gasket material. A buddy who has one has tried the K&B assembly and reports it makes the engine run a lot better.

I would not hesitate to buy another Mag 1.08, although I might go for the newer .91XLS or the 2nd edition 1.20. I will say, the OS .91 weighs the same as a .61 and will drop right in.


You also can not beat Global service if you ever have anything go wrong with your Magnum engine.

ShempHoward

My Feedback: (3)

Ed: Your 91FX problem might be that the casting for the needle assembly was actually manufactured a bit too large thereby allowing air to enter the system and cause erratic or poor running. A fellow at my field had this problem and Hobby Services sent him a new casting
and poof the problem was gone and the needle fit much better.

This might be a solution for you.

Planeboy P51

Hmmm, my 91 FX started on it's first flip, first run... Ran fine in the air too... Sure, you've got a nice running 108, that's great, but it weighs more, is bigger, and louder than the OS.