Evolution 46nx
 

Im getting 12500-600 peaked on a 12.25x3.75. Does this sound in the ballpark? I feel like it might be a touch low.

Seems about typical. Please give more details. Fuel? Plug? Muffler?

Using 10% powermaster with the stock evolution a3 plug. Stock muffler baffle in @ 12,500-600. Switched muffler to a jett and went up to 14,000-100.

OK you are pretty much right where you should be. That Jett muffler is best between 15 and 16K for max power gain but you don't want to be coming on and off the muffler while doing 3D so I would keep the prop you have. Sounds like you have the setup figured out.

I appreciate your input bud. I'm not sure what It'll do yet but I'm planning on bolting on a 9x8. I've read that the 60nx has bearing issues when unloaded further than 17,000. I would have to guess the 46 has similar steel caged bearings?

Btw thats not for a 3d plane

What airplane is it? your prop size would suggest a 3D profile type airplane.

Its currently in a u can do 40. Its going in a converted gp proud bird.

Ok that is a pretty clean airplane. Try an APC 9x7.5 pylon prop. It may be a little much for that engine but aim for 15,500 to 16,000. If it falls short you can trim the tips until you get in that range or try a 9x7 sport prop. I have had good success with both of those props on a Rossi 45 and Nelson muffler.

I've gotten 16,600rpm using a TT Pro .46 and Jettstream muffler on a 9x7 APC prop, so If the Evo 46nx can get up to at least 15,500rpm on a 9x7, you're golden. I've been told the red Jett mufflers are 15,500-17,000rpm pipes. They act kind-of like a governor as they just stop making power over 17k anyway.

Yes, that is correct. All tuned mufflers and pipes are going to have an RPM range that they work best at. Back in the day I would use a pipe on my helicopters that would help me from over revving the head speed. The Evo and the TT should be pretty much on even ground power wise.

The TT has a smaller carb on it (.270") but if bored out to .325" or so you can gain 1,000rpm. I don't know any specs on the 46nx but I agree they shouldn't be too different. The Evo is true ABC isn't it?

It is true abc. The machine work internally is actually pretty impressive. I cant think of the actual numbers but the port timing is somewhat aggressive for a "cheapy" sport motor also.

It is definitely not flawless though. It runs super sweet and is extremely easy to tune but te remote needle is mediocre quality at best. Tends to walk around a few clicks at high rpm. I pulled it apart and bent the little spring stop in quite a bit to snug it up but the best solution is a jett. Cheap stock bearings are a semi pain if you get up in rpm's also but i dont hold that against them because same with many.

Talked to Dub today. He recommended a 9×8.

I hope he ment a 9x8 pylon APC. I would hate to argue with the master but I would be very surprised if you got past 14,500 with a 9x8 APC sport prop.

My Rossi .45 had a Picco 12mm carb on it along with some sleeve and crank work. Running 20% nitro I was getting 16,800 with an APC 9x7.5 Pylon prop. The airplane really hooked up with that prop. I think the big difference is that particular prop is that the blades at the hub are slightly under cambered.

That sounds about right... I think I was hitting right around 16,000rpm on a 9.5x7 pylon prop cut down to 9.25x7 (APC) on 10% nitro. I usually use 5% nitro except in the faster engines... Sometimes I splurge and use 10-15% if I have a little left over from running the 4-strokes. I've got some 1/2a fuel laying around so I might burn that up in the TT as I have revived a project that I was going to use it on awhile back. I have some timing and carburetor mods in store for it in hopes of finding 17,000rpm on a 9x8 with the red Jett pipe and modest nitro fuel. I don't know if a stock sport .46 is going to turn faster than 15,500rpm on a 9x8 APC. At least being ABC one has a little better chances of doing that with minor work versus an ABN engine with virtually no pinch.

I was getting 18,200 with that prop but the airplane just didn't have the aerodynamics for it to work. That's usually the most time consuming task with a race plane, getting a prop that works with the engine and airplane. The fastest airplane I have built to date only turned 12,500 on the ground. Then again that was with an 11x11 on a 550 sq in 6 lb airplane.

Never specified which 9×8 prop. I assumed he meant sport because he also said 10×6. I think like everyone else im gonna have to just experiment around both on the bench and in the air in search for the right combo.

I'm surprised he'd suggest a 9x8 or 10x6 for that engine with his muffler because the engine likely won't get on the pipe with either of those. Bob Brassel is the support tech here on RCU and he told me if the engine needs to turn 15,500rpm on the ground to get the most out of the pipe's tuning abilities. But if the Evo has enough extra power over say the TT, then you're okay. Testing is the only way to determine that though...

Let us know how it goes. I'm curious to see how the Evo does with the 9x8 or 10x6 props. I'd suggest using APC at the very least as that is the prop brand Dub uses for his testing and benchmarks.

Im gonna go buy a few and get em balanced here shortly. Ill make sure to post some results of what it does. Apc are the only props I use, but if I could get my hands on some graupner (g-sonics?) Id love to try them out.

I don't have a NX, but have 8 NTs in the shop now. Well made. The stock plugs were not A3's and that was a problem. Taking out the baffle gives a good boost in numbers. I picked up another 1000 with a Tower muffler. They like 15% and up.

I ran the Evo TPS .455 with both shims out on 15%. I'm going to take one out the next time I run a NT. I have a feeling they will like the extra compression.

As to comparisons, I took off a 46FX and put on a TT. Took that off and bolted on a new NT. All ran 15% and APC 11x7's. The stock NT had a lot more power and drew a lot of comments. Another 46FX would put out hover power on a Sig Somethin Extra on 15% and a 12.25x3.75. Using the same fuel and prop the NT gave it a lot of pull out power the FX didn't have.

The chromed liner engines will outperform the nickel liner engines if both are timed the same and have similar compression ratios. The chromed liners almost always have more taper and thus a better piston seal than the engines with nickel liners. So I would expect the EVO to perform better than the TT but I doubt enough to get a 9x8 or 10x6 on the pipe even on 15% fuel. Best I ever got was 16,700rpm with a 9x7 sport prop (narrower blades than the pylon props) on 10% fuel and -200rpm on 5% fuel. I never could get 17,000rpm on a 9x7 with my TT even with 25% nitro. It just wouldnt do it, and I suspect the small carb to be the blame.

I picked up a couple props. Going to start with a 9x8 on the stand and see what it does. Ill try to get on it this week and post some results hopefully with pictures.

I fired it up on the 9x8 just long enough to get it warmed up and run it up real quick. Didnt have time to tune on it before lunch was over and had to get back to work. It was pretty blubbery rich and loaded up before I got it into a semi smooth 2 stroke......according to the globee it was at 15,000-050. Ill get some more run time on it this weekend and get some more reliable data.