TT2

My Feedback: (13)

I'm getting back in to combat mode after a short hiatus (got bit by the 3D bug). I'm trying to decide on which engines to use this year. I'm sure that this has been discussed to DEATH in the past, but it seems the posts have scrolled off.

In the past I've used Magnum XL .28s and Norvel BigMig .25s. I'm also interested in possibly using OS or Irvine engines. I'll be buying at least three new engines and I'm wanting feedback on which direction to go.

Here's what I know:

Engine Cost Weight(w/muff)
OS .25fx $85 10.8
Irvine .25 $103 12.1
Magnum XL .28 $62 10.1
Norvel BigMig .25 $65 8.03

I'm sure that the Irvine is a killer engine, but it's heavier than the others and quite a bit more expensive. The Norvels can be a pain and are prone to blowing plugs (in my experience with a couple of them), and parts availability can be a problem. The Magnums are cheap, somewhat light, seem to last forever and are pretty reliable and durable. Decisions, decisions...

I'd like to see RPM / prop data on these engines if anyone has it. The RCFAQ site seems to be down.

Any feedback would be appreciated.

-Tom

Ten-Man

My Feedback: (2)

The Only engine for me is the OS .25 FX I have about 6 of them and they all run great. Straight from the box they run as hard as anything. Slap on a Ultrathrust muffler or Kentucky mousse can and you are right there running with the big dogs. Norvels SUCK! Well for me I won't use them. They lack reliablity. They are however the lightest most powerful engine in the .25 class. If you stay with them and learn how to make them work you can make enormous power with a Norvel. With this being said everytime you think you have them figured out one will $h!t on you just when start engines is called. That's why I fly old reliable OS .25's I haven't missed a start all season that I can recall. They just work everytime. Wait a minute you live in MO???? I might be flying against you next season........Norvels rock you should buy 10 If you were unwise and chose a Norvel don't waste your money on the bearing engine the bushed engine actually make the same power and has a better carb. Much cheaper to boot. The Irvine engine has equal power to the OS and is a great engine. Neal at www.waverc.com has both Norvels and Irvines as cheap as anyone. Last time I checked his Irvine .25 was about $85.00 actually cheaper than an OS. If you need and airframe checkout www.teamseaholm.com The Avenger is the only airframe in the country that has consistantly kicked my butt. I finished 3rd Nationally this year in points and Eric Wenger and AJ Seaholm consistantly handed me a whooping flying Avengers. I might have to adhere to the old addage next year (If you can't beat em join em) Hope this helps!!! What ever you decide I hope to see you at the flightline next year with a streamer on and having the time of your life. Nothing compares to the rush of combat..........Nothing. Plus you will meet the greatest folks in all of RC flying Combat. Good Luck.

Ten-Man

My Feedback: (2)

Engine Stats All on Mouse can pipes and 9X4 MA props

OS .25FX Consistantly 18.5K
Irvine .25 Consistanly 18.4K
Mag .28 Varies a little 18.2-18.8K
Norvel Big Mig .25 Who Knows (pretty inconsistant) 18.0K-19.4K At the higher rpms that the Novels run at you will be forced to run a bladder fuel tank. Standard tanks will foam uncontrollably and you probably won't even get them to run. This adds slightly to the cost and complexity but I now run bladder tanks on all my planes for greater consistancy. The Mags also have slightly lower grade Con rods and I have seen several break hitting high rpms yet it is still a good choice. Parts for Mags are dirt cheap also.

stdun

What, are you stuck on 20 size motors? How about an os46fx? Talk about power! I have one on my Predator X and I doubt there is much faster, plus the take off speed with a ribbon is like a slingshot. I've also flown 46's on my spads for a couple years with much success. Open is open, isn't it? However my local club did outlaw the os61fx I had on a 5' winged spad, chickens.

ChuckAuger

My Feedback: (12)

Open B is limited to .30 cu in.

The weight of the Irvine .25 given is with muffler, the weight of the OS .25 is less muffler.

JuniorPilot

Well me personally i just bought a magnum .28 off a guy nib for $50 cdn! so thats what i'm going with and from the stuff given here it looks to be the best engine!

TT2

My Feedback: (13)

Chuck, the .25fx is listed at 8.8 oz without the muffler, 10.8 oz with (according to Tower's website).

Ten-Man, I already have some airframes lined up...unfortunately, they're the Avengers...unfortunately for everyone else that is! heehee! I keep leaning towards the Magnums since they're so dang cheap. I usually go with 'you get what you pay for', but in combat I try to keep things in perspective...everything's got a limited lifespan and should be considered expendible. I too thought I had the Norvels figured out (seal up the leaks EVERYWHERE) but they've taught me that they are not to be trusted. I've probably spent more on plugs than I did on the engines. The Magnums I had never ate plugs...one would last an entire year or longer.

I don't know how competitive I'm going to be this year...it will be difficult for me to travel much. I'm just going to practice, practice, practice and attend area meets whenever possible. I might see you if you get up around KC this summer. Have fun and thanks for the info!

-Tom

ChuckAuger

My Feedback: (12)

Sorry, just seems like the weights for OS engines are always posted here w/o muffler while the Irvines are given w/ muffler, makes the OS seem a LOT lighter. I hadn't done a head-to-head in a while. FWIW the Irvine is listed as 9.4 oz w/o muffler.

TT2

My Feedback: (13)

Thanks Chuck. I hadn't found the weight of the Irvine without the muffler. The stock muffler on the Irvine is a PIG at 2.7 oz. Now knowing that the Irvines can be had for $85 and they're only slightly heavier (without muffler) than the OS and Magnum, that makes my decision a bit more difficult...but this is exactly the kind of info I was looking for.

-Tom

Lou Melancon

TT2,
I've only flown Norvel BB .25 in combat, but agree with all your observations and those of Ten Man. This year and next I am not flying Open B so I am only using them in scale.

At the Nats this past year I saw a new reasonably priced engine that appeared to outperform all the others. It is a Webra .25. The one I saw was turning a MA 9X4 at 20K on 15% fuel. When the owner told me he was getting this kind of power I blew it off as exaggeration but when pitting with him at the Nats I saw it. He got his from www.flyingzhobbies.com for about $85.

The folks who are running Magnums successfully have worked on the crank timing to bring them into the right timing range to match the rpms we want to run. Lee Liddle won the US Nationals with a Magnum .28, but it wasn't stock and it was running on a pressure bladder so you can't compare his results to what you will get with an out of the box Magnum.

If you want extreme reliability, and not have to worry about your engine so you can concentrate on your flying Ten Man has given the best advise. Buy OS .25FXs and put Kentucky Mousse cans on them (also available from Flying Z) and you will have your power plant issues completely resolved.

DualdudE

And what about an MVVS .25 Combat? This engine was designed for combat (The one in my avatar) Just ordered one..didn't let it run yet...but heard great stories about them I'm quite fond of Irvine too, but when i look at the specs, the Irvine .25 seems to be less powerful than most other .25 engines. The MVVS .26 also could be an option.. It's a little cheaper and weights a little less than the .25 Combat (due to the large head it's a bit more heavy).

Lou Melancon

DualDud,
The MVVS was in favor about three years ago in combat. At that time folks found that you had to buy 3 to get one good one. That one would run very well. They are known for power and durability but not for quality control. The combat community is fickle. After one or two bad experiences with a brand they shy away from them. No one in the US combat series ran MVVS engines with success in the last couple of years so the brand has an uphill battle to convince fliers to invest in them.

thojo

another thing in favor of the OS 25FX. If you have a problem in the pits, you got alot of guys next to you with spare parts they would in most cases be happy to lend or give you to get you back in the air. If you fly odd-ball engines, your on your own, cause nobody at the field will have any spare parts you may need...

To me the reliability of the OS 25FX's outweight any possible performance advantages of any other engine may have...

Hat Trick

The FX is a great engine and very reliable. Also has the least vibration of any engines I've seen. I've got a box full of MVVS's if your interested!

Montague

The Irvine is more trouble than it's worth, IMHO. AJ uses them, but they are re-worked. The stock ones I've seen have not impressed me. And Sig is the importer, which is enough to convince me to have nothing to do with them.

The OS FX is the best all around combat engine IMHO.

I mostly run the Mag .28 myself. On a mousse can, they are as good as anything out there, and dirt cheap. Yes, Lee's are reworked, but mine are totallly stock, and I certainly didn't lack for power this year. But the carbs require TLC. I've been using them for 2 seasons, so I'm good at keeping the carbs together (usually).

aseaholm

My Feedback: (1)

A stock Irvine with KY Mouse can or UltraThrust muffler is as powerful as any engine on the market. The motors I run have had the crank timing opened up as well as the exhaust duration. These mods net around 700 rpm. My Irvines, modified, consistently turn a 9x4 MAS propeller between 19.0K and 19.2K on the average combat day on 15% nitro. A stock Ivine with after market pipe will consistenly turn a 9x4 MAS 18.5K on 15%.

Like any engine, the Irvine has its weaknesses. The thing I have been most impressed with though is their longevitity. I have 2 engines I purchased in 2001 that have many gallons of fuel run through them and have been stuck in the dirt many, many times. These engines still turn with a couple hundred RPMs of my strongest engine. That's a lot of bang for your buck in my opinion.

There a couple things with the Irvine that needed attended to.

1) The carb barrel screw needs to be glued in place or it will back out. I generally red loctite this screw in and then put a dab of IC2000 CA over the head. IC2000 is the black CA used for gluing fiberglass. Regular CA works fine as well.

2) The phillips screws that hold the carb in need to be replaced. The factory screws are soft and will back out. Replace the 2.5 mm screws with a good hexhead machine screw and red loctite them in place.

3) Once bent, the needle valve will break off from the cylinder. This usually occurs after a hard dirt nap or nasty mid-air. This bit me in the final round of the NATS this year and I think I may try a remote needle valve to eliminate this problem.

IMHO, Magnums are more trouble then they're worth. I own 2 of them and the carbs are notorious for falling apart and the quality control was not very impressive.

As others have said here, the OS FX is probably the best all around combat engine. Good power, super dependable, and parts are readily available. I chose the Irvine because at the time I could get them from direct from England for about $70. If I had it do all over again it would be a VERY tough choice between Irvines and FXs.

Tom,

Just like anything, you'll likely get a dozen different answers to your question. I think the best piece of advice is to stick with one engine and learn all its weaknesses. Ohh, and use those Norvels for paper weights and save yourself a whole lot of frustration...

Looking forward to seeing you on the flightline this season...

A.J. Seaholm
TEAMseaholm.com
[email protected]

TT2

My Feedback: (13)

I appreciate all the help guys! I'm starting to lean towards the OS. The price for OS parts is scary but if they stay together then I guess it's nothing to worry about. I had been favoring the Magnums since I know how they run, but those carbs can be a pain. The carb on my neighbor's .28 keeps throwing the screws that hold the carb to the crankcase, and I can remember several times with my Magnums that the carb barrel screw kept wanting to eject itself (though I managed to catch it just in time). I've had very few OS engines over the years because I was always on the lookout for a cheaper (and sometimes better) alternative. BUT...I do have an OS 1.60fx and it's probably the best glow engine I've ever had.

That being said, where's the cheapest place to buy the OS .25fx? [link=http://www.donalds-hobby.com]Donald's Hobby Center[/link] has them for $79.99.

Thanks again,
-Tom

Montague

Hmm, re-reading my post, I might have given the impression that I think stock Irvine engines don't produce power out of the box. Actually, the ones I've seen have all produced solid power. I do think their carb has some issues, and the prices I've seen for them make them close to, or more expensive than an OS, so between an Irvine and an OS, I'd personally go OS for the same price.

The Magnum, however, is enough cheaper to make it worthwhile for me to run them. They do shed carb parts, so you have to work on the carb before running to fix it up, not at all unlike what AJ was describing for the the Irvine. First step is to remove the throttle stop and barrel retaining screws and put them back in with a generious amount of locktite. When you mount the carb to the engine, again don't skimp on the locktite. I've also been replacing those screws with slightly longer ones from the local Ace hardware. The replacements also seem to take a screwdriver better. But the key with the Magnums is putting fuel tubing over the high speed and low speed needle valves. A bit of large diameter tubing over the low speed screw will actually touch the screw where it sticks out of the black houseing a little, and prevents it from turning and stops air leaks all at once. A bit of normal fuel tubing on the high speed needle stops the air leak, and really makes the needle a lot easier to set right. With out those fixes, the Mag carb will self-destruct.

Btw, one of the really REALLY cool things about combat is that engine power is not super-critical. You can win with a little less speed and power. I've been using stock Mag .15s in A class against guys with more powerful OS CV-As, Norvels and other engines, and I do pretty well with them. It's much more important to know your engine and be sure you can start it on time, every time, and keep it running though the heat. I'd trade 1500rpm for 100% reliability any day. If I ever get my airframe problems sorted out in B class, I might actually be dangerous there too.

1Jimbo

My Feedback: (2)

I have two GMS.25's that are working GREAT with a Jett muffler.