Novel

[Casey]

Anyone can share their experiences regarding Novel NV Big Mig 061 and 0.074 as to ease of use, starting, holding a setting, durability and thrust.

[Dan McEntee]

  Check out the 1/2A section, do a search there and you will find volumes on the Norvel line of engines. I'll just say here that we used them on the airplanes we fly at the KidVenture circles at Oshkosh and they have untold numbers of hours on some of them. They are a bit different if you have never handle ceramic coated engines before and some people find them way too tight but follow instructions and read other people's experiences here and you will be more than satisfied with the engine.
     Type at you later,
   Dan McEntee

[kenneth cook]

          Knowing what type you own is important. There were two types which are the Big Mig and the AME. The Big Mig is for sport and the AME is for higher performance. These two were available in .049 and .061. I have never seen a AME .074 but that doesn't mean that they didn't exist. As far as I'm aware, they were only available in the Big Mig version. The .061's are terrific engines offering a lot of rpm's. They don't typically care for larger pitched props and I mean props that are over a 3 pitch. These engines turn up and APC offers a variety of props that are useful to them. However, they don't fit the shaft and require a bushing or a piece of small fuel tubing within the prop hole. The .074 engine is somewhat trapped between prop sizes. Master Airscrew offers a 6.5x3 and props typically 7x3-7x4 suit this engine and can be trimmed down if needed.

         The nice thing in regards to the Norvel Big Migs, they have mufflers which robs a bit of power but keeps things mild in terms of noise. The Big Mig will run just fine on 10% nitro as well as the .074. These engines only need 20% oil 50/50. Not to add anymore confusion but Norvel went through some changes in cylinder technology. The earlier squarish heads were ABN I believe while the later is a ceramic coated aluminum which goes by their trademark Revlite. The Revlite version are round heads which have a olive drab or brownish appearance. These engines take a different method of breaking in as the cylinder and rod can be damaged unless the proper technique is used to break it in. Once broken in, they are extremely reliable and durable. I'm quite certain doing a search on here will reveal the procedures used.

[944_Jim]

Twin .074 Big Migs:


For build, go see https://www.coxengineforum.com/t10666p25-bhm-mosquito-in-ms-build?highlight=BHM+Mosquito

They will flood easilly IF the tanks are on top of the wings. Once the tanks were mounted below the wings, the engines draw fuel just fine. This puts the center of the tanks just below the venturies/spraybars. They needle fairly easilly on ~22%N/22%O (50/50 synth/castor). I sneak up on lean enough to drop rpms, then go rich enough to slow down the engine, and then back up to a just-clean 2-stroke. In other words, I don't try for as lean as possible. There is a broad spread on turns for all this. Probably 2.5 turns from side to side. Once set,  I do a ground run for one tank (both sides at the same time). Then I fly without touching the needles again. These engines are swinging 7x4 MA props.
I love the engine, so I have been scrounging them up without advertising to my wife...but somehow she knows. I guess the monthly bank statements are rat-finking me out!

I have a bunch of AP Wasp .061s with Jan Haluzko venturies. I treat them the same as above. The needles are more touchy, probably 1.75 turns for same action. While I would NOT call them "Norvel-equivalents," they did closely resemble my Norvel .061 Big Migs in sound, bench-test rpms and starting. The Norvel Big Mig .061s needles much like the .074s. So I will say, once a plane is well sorted on an AP .061, then it will get switched to the Norvel .061. My 1960 Scientific P-40 will get a quick flights with a Cox Black Widow before finally being repowered with a Big Mig .061 later this spring.

I have little experience with Cox Medallion, but what little I do have leads me to understand the Norvel Big Migs behave like a Medallion with similar fuel draw behavior/fuel system requirements.

I have ZERO experience with the AMD/AMD/AMA (whatever the different alphabet combos are) variants, but understand them to behave like Tee Dees in fuel draw/fuel system requirements. Pressure and location matter more to these than the Big Migs. Again, just anecdotal.

[944_Jim]

Oh, and I bought my .074s new in the box. They got quite a bit of bench time for break in. They were difficult to start at first, but finally got to the point where they reliably/quickly started by electric finger. Once broken in, they got moved to the Mosquito, where they started to really bed-in and sweeten up. I'd say they have an hour or more of bench time, and about the same on the airframe. The later flights, I could actually finger-start after the first electric start of the day. They are really sweet engines now! No more black/grey slobber from the coating breaking in/polishing...but it was kind of scary the first time I saw the black/grey splatter.

[Clint Ormosen]

So how can you tell the difference between the Big MiG and the AME ?? I have one of each NIB but they look absolutely identical. They both say Revlite on the instruction manual.

The Big Mig is on the left in the pic.

[Chancey Chorney]

Easiest way to tell the difference is to pull the head and count the ports. The AME has 3 bigger ports and the Big Mig has 5 smaller ports.

[Target]

So how can you tell the difference between the Big MiG and the AME ?? I have one of each NIB but they look absolutely identical. They both say Revlite on the instruction manual.

The Big Mig is on the left in the pic.

If you look closely in the exhaust port with a flashlight or backlight, you can see the ports with the piston at BDC, without taking the head off.
That being said, it is easier to get the head off and back on, than the muffler, in my opinion.

And by the way, Norvel was notorious for marking the boxes wrong. just because the engine on the left came from a box that says "BigMig", doesn't necessarily mean it will be. This is what I have been told, and I did find a couple in my stash with miss-marked packaging.

R,
Target

[Chris Fretz]

         The Big Mig will run just fine on 10% nitro as well as the .074. These engines only need 20% oil 50/50. Not to add anymore confusion but Norvel went through some changes in cylinder technology. The earlier squarish heads were ABN I believe while the later is a ceramic coated aluminum which goes by their trademark Revlite. The Revlite version are round heads which have a olive drab or brownish appearance. These engines take a different method of breaking in as the cylinder and rod can be damaged unless the proper technique is used to break it in. Once broken in, they are extremely reliable and durable. I'm quite certain doing a search on here will reveal the procedures used.

It kinda looks like I have the olive drab one you mentioned. The instructions say revlite. However the instructions don't seem to tell you anything about how to break it in. How would you break this in Ken?

Thanks
Chris

Sent from my SM-G920V using Tapatalk

[kenneth cook]

         Chris, whenever I break those engines in, I first clean the parts in alcohol. I reassemble and tape the drive washer to the case where the piston is just covering the port. Fill the cylinder with straight castor oil, lightly screw the head on and leave it sit soaking for at least a day. The metal is porous and the castor oil goes into it. Norvel recommends not installing the plug at this point and turning the prop the opposite direction of how one starts it for 200-400 revolutions. What I do is chuck the end of the shaft in my drill press and on low speed I heat the cylinder with a heat gun and then turn on the drill press. I use my hand to prevent the crankcase from spinning, when the resistance begins to increase, I stop and reheat again. Heat is the solution to preventing galling. After about 10 minutes of that I'm pretty much ready to go but I still keep the heat gun by my side. I like to up the castor a bit for the first runs and I generally use 25% dropping back to 20% after a few runs.

[944_Jim]

Like Mr. Ken says, pre-soak the engine over night. I won't argue with castor oil, but will say I plunked mine in a cup of 10 wt engine oil. The coating needs to absorb the oil prior to starting. I sat and watched TV while hand-cranking mine...for about 90 minutes.Occasionally I'd give the "cranker" a break. Yeah, my hands got tired.

I discovered the engine did still "pinch" for some time after the start/run cycles. You want the engine up to operating temperature for many short runs. Don't go slobbering rich, nor do you want dead lean. The exhaust oil needs to carry the "polished off" coating out of the engine. I used a 6x3 prop during the jnital break-in, just to get the engines loosened-up, and then moved to a 7x4 for normal operation. The engine needs to come up to normal operating temps to stabilize the P&C. Lots of two/three minute runs!
I run approx 22% oil, with half that being castor. So while breaking in, I would start rich, sneak up to string lean, and go back to rich without a significant rpms drop...ISTR this about 1/4 turn to rich  from a clean, lean 2-cycle.

i also kept spinning the prop off (electric finger) as the engine broke in. One scary moment was a flood-out that did not clear out even with the plug removed. An overnight sit, and flush with alcohol sorted out the engine. Then it was "resume the break-in." This was while the tanks were mounted on top of the Mosquito wing, but after quite a bit of bench time.

Now the engines both have a good pop, with smooth build-up and snappy release over TDC.

YMMV!

[Chris Fretz]

Thanks guys!  Much appreciated.

Chris

[Casey]

Thanks, everyone for the input