Author Topic: Evolution .36 (Read 3812 times)

fred krueger · « **on:** November 21, 2012, 10:03:25 AM »

Many fliers that I know have run problems with the Evo .36. Mine ran very erratic. I made my own true venturi (.160" dia.) to improve fuel draw as the supplied ones are all large. I tried slightly decompressing the engine, different prop loads, etc. and finally just put the engine away. A couple months ago I had an inspiration and tried further decompression. The run improved. Recently, Bill Smith and I put our heads together and did some testing with my engine mounted on an ARF Primary Force.
The engine has been decompressed with 0.034" head shims. A Merlin 2011 plug (cooler) was installed to retard the timing. A Tornado 11x4 prop was installed (a couple of other prop loads worked OK, but this seems the best). Currently running 10-22 fuel. The tank could be moved down a touch to equalize the run in the manuevers, but otherwise we're happy. The engine runs in a nice 4-stroke, breaks in manuevers, without any surging, and comes back immediately. We plan on further tests as weather permits, eventually putting the engine in my Tucker Special to test it's capabilities in a full fuse model. Here's the link to a partial pattern (my P-Force only has a 3 oz. tank).

Fred

Joseph Lijoi · « **Reply #1 on:** November 21, 2012, 10:41:48 AM »

The needle valve is an issue. I have done similar changes but I would mention that the engine ran best for me on Cool Power all synthetic fuel. You might want to try it. It ran better for me than the the powermaster GMA or the CP Omega.

Paul Wood · « **Reply #2 on:** November 21, 2012, 11:13:14 AM »

Are you guys using the remote needle assy? I have a new EVO .36 and I mounted an OS NVA into the stock venturi. Works very well, but I'm still trying to get a fuel tank issue sorted out, so I can't say much about the performance yet. It runs great on the test stand, but my tank problem is creating a rich to lean run during the duration of the flight. I'm using Wildcat 10/17 fuel bumped to 20% with additional caster. After sorting out the lean run issue, I'll switch to Power Master 10/17 caster/synthetic blend. Using an OS #8 plug and Top Flight Power Point 10x4 prop.

Paul

fred krueger · « **Reply #3 on:** November 21, 2012, 03:29:30 PM »

If you check out the start of the video, you'll note that I am running a Super Tigre NVA. Bill Smith and I are of the opinion that some folks have good luck with Cool Power because the compression is effectively lower with the lower oil content and viscosity of the 16% all synthetic blend. After decompressing the engine with shims, I am able to run 22% oil (half castor) and have a very broad needle adjustment range.

We plan on opening up the heads at some point. We'll probably need a 4-jaw chuck as the heads are not round and the glow plug is not centered. We will do more reports on our mods as weather and time permit.

Fred

Chris Brainard · « **Reply #4 on:** November 21, 2012, 05:49:58 PM »

I'm running an Evo .36 in my overweight (49 oz.) Caprice. Our flying field is approximately 6,000 feet elevation (near Golden, CO). I had the same initial problems others have reported but am now extremely pleased with the performance. The single biggest improvement was to go to R/C fuel. I'm running Patriot fuel which is 18% all synthetic (Klotz) and 15% nitro. Here are the physical changes to the engine: .272" diameter delrin venturi with case drilled for Super Tigre N.V.A., squish band narrowed .050". APC 11 1/2" x 4" prop cut down to 10 1/2" x 4" with tips shaped to original outline and taper. Launch 10,600 RPM. The engine runs in a rich 2 stroke and breaks smoothly back and fourth to a leaner two stoke. It runs very consistently and is very easy to needle. The engine seems to like to run at a higher RPM and turn a smaller diameter prop than my Magnum .36 or modified Thunder Tiger .36. Also, when trying to switch from the R/C fuel to 10/22, the run went completely to h__l. Switching back to the R/C fuel instantly "fixed" the run.

I don't like all those goofy cooling fins on the head or case. After running the engine with those on for a while, I finally machined them off. In my opinion, the engine looks a lot nicer, weighs less, and has not had any issues with overheating.

It's a very good engine. I now own two of them and may look for another one.
Chris

YakNine · « **Reply #5 on:** November 23, 2012, 08:49:30 AM »

Has anyone picked up one of the new engines with the new venturi setup that they have been rumored to be coming out with ? T.J.

dennis lipsett · « **Reply #6 on:** November 24, 2012, 10:42:42 AM »

Quote from: YakNine on November 23, 2012, 08:49:30 AM

Has anyone picked up one of the new engines with the new venturi setup that they have been rumored to be coming out with ? T.J.

While it's been rumored to be coming they have restocked at least twice and still have not made the change. They really do not answer any emails to them pertaining to the subject and it is a source of discontent on my part that they really aren't listening to the market that they wish to serve.

Dennis

Richard Koehler · « **Reply #7 on:** November 24, 2012, 06:33:50 PM »

I'm also using an OS needle in the stock small venturi, and my evo runs great. Does a wet two until the nose comes up on my modified Banshee, than breaks to a hard two for more power. I'm using about 5 1/2 oz of fuel for 7 minutes of flight with approx 2 1/2 gals of fuel thru the engine. I'm hoping fuel economy will improve since I've heard on this forum evo's take a long time to break in.

YakNine · « **Reply #8 on:** November 24, 2012, 08:56:32 PM »

I asked about it last year at the WRAM's show most of the reps didn't know that Horizon even sold a CL engine. They were more interested in pushing their radial engine and park flyers , didn't even have a cl engine in their huge display. T.J.

dennis lipsett · « **Reply #9 on:** November 24, 2012, 09:52:11 PM »

Quote from: Richard Koehler on November 24, 2012, 06:33:50 PM

I'm also using an OS needle in the stock small venturi, and my evo runs great. Does a wet two until the nose comes up on my modified Banshee, than breaks to a hard two for more power. I'm using about 5 1/2 oz of fuel for 7 minutes of flight with approx 2 1/2 gals of fuel thru the engine. I'm hoping fuel economy will improve since I've heard on this forum evo's take a long time to break in.

Thats a lot of fuel for a 36. I don't know what your using but Powermaster 5/22 can get me through the pattern on 4 oz of fuel. As I've posted before as far as I'm concerned the smallest venturi is still too large for the engine and I have had venturis made by Jim Lee and am using Randy's needle valve assemblies through the cinch bolt hole. My origional engine is using an Irvine Jen venturi and NVA with the same results. My runs closely duplicate yours.
Dennis

fred krueger · « **Reply #10 on:** November 25, 2012, 02:36:30 PM »

Dennis,

I believe Jim told me that he was making venturis for these. He's also done some great work on the EVO .60. I pitted for him at the NATS where he was running the .60.

Since I have a small lathe, I cut my own venturis. The one on my EVO (photo) is .160 dia. with a sprinkler. This is MUCH smaller than the smallest included with the engine. I usually follow Klaus Maikis recommendations for venturi cross-section as his data provides a real good starting point. I'm using a MVVS NVA (similar to the ST) with a sleeve soldered to it to fit the cinch bolt hole.

Fred

dennis lipsett · « **Reply #11 on:** November 26, 2012, 08:00:17 AM »

Fred,

That looks about right to me.

Dennis

Brett Buck · « **Reply #12 on:** November 26, 2012, 10:51:06 AM »

Quote from: Chris Brainard on November 21, 2012, 05:49:58 PM

The single biggest improvement was to go to R/C fuel. I'm running Patriot fuel which is 18% all synthetic (Klotz) and 15% nitro.

I haven't run my engine yet, but I would note that the instructions say to use Cool Power. That will certainly improve any fuel draw issues since the viscosity of the fuel is much lower than typical stunt fuel. It takes a lot less suction to get Cool Power through the pipes than it does to get Powermaster GMA through the pipes.

David and I (at the prompting of Brian Eather and as mentioned by Brad "Godzilla" Walker in his inimitable style) have experimented quite a lot with fuel supply restrictions, both by modifications to the fuel system and different fuels. In some cases it makes a HUGE difference. And all based on the amazing effects it has on 4-strokes (and in particular, events at the 2002 NATs).

Brett

dennis lipsett · « **Reply #13 on:** November 26, 2012, 07:03:53 PM »

Brett,

I use Cool Power and Omega but for peace and quiet I have it in a Powermaster can. Saves me a lot of grief at the flightline. Definitely recommended for the 60.

Dennis

Joseph Lijoi · « **Reply #14 on:** November 27, 2012, 10:48:05 AM »

Quote from: dennis lipsett on November 26, 2012, 07:03:53 PM

Brett,

I use Cool Power and Omega but for peace and quiet I have it in a Powermaster can. Saves me a lot of grief at the flightline. Definitely recommended for the 60.

Dennis

Good idea. Eventually some one will figure out that you are using synthetic lube because your engine will be clean.

A cheap fix is the small OS RC NVA and the stock small venturi sleeved with some 7/32(?) aluminum tubing and JB Weld. The CP made quite a difference. I really didn't want to get too crazy with modifications. I think the engine needs a lot of break in and will consume less fuel after time. 3 3/4 ozs with this set up for 7 minutes with the Cool Power.

I really like the engine. Honestly I think the remote needle valve might work once the engine is fully broken in and vibrates less, but I really don't have enough time to play.

dennis lipsett · « **Reply #15 on:** November 27, 2012, 04:12:58 PM »

Quote from: Joseph Lijoi on November 27, 2012, 10:48:05 AM

Good idea. Eventually some one will figure out that you are using synthetic lube because your engine will be clean.

A cheap fix is the small OS RC NVA and the stock small venturi sleeved with some 7/32(?) aluminum tubing and JB Weld. The CP made quite a difference. I really didn't want to get too crazy with modifications. I think the engine needs a lot of break in and will consume less fuel after time. 3 3/4 Oz's with this set up for 7 minutes with the Cool Power.

I really like the engine. Honestly I think the remote needle valve might work once the engine is fully broken in and vibrates less, but I really don't have enough time to play.

We ran the 36/46 extensively in R/C profile 3/D models for a few years ( 5 to be exact) with excellent results. Fuel was always 30% Cool Power Heli fuel and props went up to and including the APC12.25X 3.75 prop. It was not modified in any way and the remote NVA was used with the stock carb. It was/is one of the most reliable engines that anyone could ask for with 1 flip starts the norm and seriously reliable and linear throttle for both engines.
Given that description it is recognised that most of the current problems with the engine are the venturi sizes selected and in this case the remote nva is a distinct problem. Fortunately many have arrived at a satisfactory solution to get acceptable runs. now if only Horizon Hobbies would act on feedback given they would have probably the most perfect sport engine made available to the C/l community in years. Yes I know that the LA46 is good but the Evolution has the potential to offer considerably more value for your hard earned cash then the OS. Now if we could get them to do a 45 and keep it light and a 25 they could give OS the first decent run for their money in years,and I believe that they could very well win.

Brett Buck · « **Reply #16 on:** November 27, 2012, 08:23:45 PM »

Quote from: dennis lipsett on November 26, 2012, 07:03:53 PM

I use Cool Power and Omega but for peace and quiet I have it in a Powermaster can. Saves me a lot of grief at the flightline.

I used to do something similar with Byron fuel. I ran that at several NATs but naturally didn't want anyone to know about it. And, one engine I had would run *only* on Byron. Any other fuel, it had the "like you flipped a switch" flameout, even on the test stand.

In this case, the fuel could be almost the entire issue. Someone managed to fly their airplane with the stock venturi, I know for certain that it was tested in the "as delivered" configuration. Particularly in the case of a complex fuel path and the restriction in the fuel line well upstream of the venturi, even tiny changes in the viscosity of the fuel could make a huge difference in the ability to draw fuel. We found a similar effect on a spraybar that was designed with a very small inlet bore. It was extremely sensitive to the fuel temperature, and boring it out (as deep as it could be without removing the needle seat) made it very insensitive.

Someday I will tell you about my regenerative header cooler/fuel pre-heater.

Brett

dennis lipsett · « **Reply #17 on:** November 28, 2012, 02:05:33 PM »

Someday I will tell you about my regenerative header cooler/fuel pre-heater.

Brett,

You might as well tell us now. It's winter, flying is iffy, and we need tall tales to get us through the season.

Dennis

Mike Greb · « **Reply #18 on:** November 28, 2012, 02:11:02 PM »

At the 2011 nats I was the only person to admit to using Cool Power fuel. Been using powermaster 10%nitro 17% oil lately. It is about a dollar a gallon cheaper at my LHS.

Joseph Lijoi · « **Reply #19 on:** November 28, 2012, 04:33:46 PM »

Quote from: dennis lipsett on November 27, 2012, 04:12:58 PM

We ran the 36/46 extensively in R/C profile 3/D models for a few years ( 5 to be exact) with excellent results. Fuel was always 30% Cool Power Heli fuel and props went up to and including the APC12.25X 3.75 prop. It was not modified in any way and the remote NVA was used with the stock carb. It was/is one of the most reliable engines that anyone could ask for with 1 flip starts the norm and seriously reliable and linear throttle for both engines.
Given that description it is recognised that most of the current problems with the engine are the venturi sizes selected and in this case the remote nva is a distinct problem. Fortunately many have arrived at a satisfactory solution to get acceptable runs. now if only Horizon Hobbies would act on feedback given they would have probably the most perfect sport engine made available to the C/l community in years. Yes I know that the LA46 is good but the Evolution has the potential to offer considerably more value for your hard earned cash then the OS. Now if we could get them to do a 45 and keep it light and a 25 they could give OS the first decent run for their money in years,and I believe that they could very well win.

Nice post about your RC experience with the engine. Seems like you were getting a lot of good service out of the Evos and looks like you were swinging a fairly large prop. In terms of dollar value the Evo replacement parts are very cheap, like 15 dollars for a crankcase. Also the mounting hole pattern for the 36 is the same as the FP 25, but is about a half inch longer. The 60 uses a smaller 46 or 51 case (I think).

Joseph Lijoi · « **Reply #20 on:** November 28, 2012, 04:47:18 PM »

Quote from: Brett Buck on November 27, 2012, 08:23:45 PM

I used to do something similar with Byron fuel. I ran that at several NATs but naturally didn't want anyone to know about it. And, one engine I had would run *only* on Byron. Any other fuel, it had the "like you flipped a switch" flameout, even on the test stand.

In this case, the fuel could be almost the entire issue. Someone managed to fly their airplane with the stock venturi, I know for certain that it was tested in the "as delivered" configuration. Particularly in the case of a complex fuel path and the restriction in the fuel line well upstream of the venturi, even tiny changes in the viscosity of the fuel could make a huge difference in the ability to draw fuel. We found a similar effect on a spraybar that was designed with a very small inlet bore. It was extremely sensitive to the fuel temperature, and boring it out (as deep as it could be without removing the needle seat) made it very insensitive.

Someday I will tell you about my regenerative header cooler/fuel pre-heater.

Brett

Reminds me of a long time ago when I was just getting into this stuff and was hanging out with Art Adamissin in the basement. They were using Cool Power all synthetic lube and recomended it for use in the FP 40 that had replaced the Max 35. At the time the FP had a steel piston/liner. I guess people were insisting on running it on all castor and the results were flameouts. They redesigned the head or something because people wouldn't use the Cool Power, insisting that it was bad fuel.