Sarosh

Hello, so here it is, I purchased a OS Max 55AX for my Funtana 50. I broke in the engine according to the engine manual and my knowledge in the past with other engines. It is properly broken in, but i used Slimline Pitts. Well, I have ran through like 7 tanks, and i can not go under 3 turns without the engine reaching over 250 degrees. ON the ground full throttle testing, how long do you guys let it go at full throttle to test things out? I held it at full throttle for like 5-10 seconds, then read the temp, anything under 3 turns it goes past 320 degrees. Tach is around 11300-11700 rpm. The spec states it produces its max power at 16,000 rpms and normal starting setting on the main needle is 1.5 turns. I cant get it anywhere close to 1.5 without it overheating.

After a discussion in another thread, it seems like that its not getting enough pressure in the tank. So i tried to use my stock muffler that came with the engine, and it is still the same results as using the Pitts muffler. I am using OS #8 plug, 15 percent Cool power fully synthenic fuel.

What temps are you guys with the same engine running at? what is the normal operating temps? using stock muffler, or pitts or what muffler? Whats going on with the motor? does it need to break in more longer than 7 tanks?

rainedave

My Feedback: (1)

It sounds like your engine is probably in a cowl. If this is the case, you will typically need to have proper ducting and intake/exit openings to ensure it doesn't overheat.

Personally, I have never taken a temp reading of any engine I've ever owned. I very quickly pinch the fuel line. If it speeds up I lean it a little until pinching the tubing does not increase the rpms. If the rpms drop when pinching the tubing I richen it immediately as that is too lean IMO. I also use a tachometer sometimes to find peak rpm and then back it off a few hundred. The only engine I ever damaged from a lean run was the very first one I ever owned - a ringed K&B .40 - and I had no idea what I was doing back then.

David

Julian537

My Feedback: (9)

Why are you taking temperature readings? This is something that the car guys do! Temperature is not something most airplane guys check!!! We check to see if it is lean or rich! Do the pinch test? does it die? or does it increase in RPM? this is at wide open throttle.
Are you running it with the cowl on or off?
What size prop are you using? IS the motor dying? Does it quit running at anytime when you are giving it throttle?
Please provide more information

Sarosh

Well, i will have to try the pinch method with the cowl off, the cowl's bottom is pratically all cut open, the 2 inlet holes have been cut 1/4 inch off around it to allow extra air in, also the side of the cowl has a hole the same size as the head, but head does not stick out at all. i am running 12x6 prop.

the reason i use temp gun is because i dont want to melt this expensive engine! i've been around cars and trucks forever, i was into planes before i graduated from HS in 97, then completely stopped it, but continued cars and trucks. But i do have 4 helis. everything runs great, except for my first nitro car lol, but its all good now. so this plane is the first plane i bought by myself. I just dont want to fry the engine. Plus i have read other peoples comment on the engine on this forum and other places, they saay that it verticals crazy, some with funtana 50. mine, just barely wants to climb. plus they say they are running 14,000 rpm or more. i cant get it past 11500. but again, i will try again tomorrow with the pinch method. I used the tach to watch it until it drops then back out few clicks, but when i do that, it overheats and dies.

Let me do another test tomorrow and get back.

rainedave

My Feedback: (1)

With airplanes it is imperative to eliminate as many variables as possible when setting up an engine. Therefore, I always run mine on a test stand first. If it performs well on the stand, but not in the plane, then the problem is definitely with the plane, not the engine. It might be the fuel system, or, in your case, the cowl. But, in order to know that you have to first know if the engine runs properly. It can be very frustrating and extremely time consuming to try and diagnose problems with the engine in the plane.

But, if you don't have a test stand, do this:

Use fuel with at least 18% oil, preferably with a good amount of castor. Triple check the fuel system for pinholes or tears in the tubing (inside and outside the tank). Make sure the centerline of the tank is at or just slightly below the level of the needle valve when the plane is level. Drop down to an 11x6. And, finally, fly the plane without the cowl.

If it still acts up you will need to run it on a test stand to determine if the problem is with the engine.

David

blw

My Feedback: (3)

The temp measurement probably won't tell you anything about the engine. What prop are you using? Has it been tuned?

CustomPC

12x6 at 11,700rpm is about where it should be. You'll never see the AX reach the advertised 16k rpms on large props. It's marketing hype.

Get some fuel with 18-20% of oil and at least 3-5% of that is castor.
"IF" the motor is truly overheating then the synthetic oil will be taken past it's flash or burn points and will burn away reducing the protection to your engine. Castor is the opposite, it protects more as the temp rises and will protect your motor from lean runs.

3 Turns out is a lot. It should be a definate 4-cycle burble at WOT on 3 turns out. Are you sure your not counting half turns as 1. I've made that mistake a couple of times.

If it's definately 3 turns out and running lean then you need to examine your fuel lines closely. Check the clunk line for holes. Make sure there are no holes in the lines between the tank and carb. Are you running a filter? They can sometimes leak or cause cavitation and air bubbles in the fuel lines.

Sarosh

The reason i dont run castor is because it makes brown messy residue, that is as i remember from my flying days in the 90's maybe it was a higher percentage of castor oil that i used, cant really remember what fuel i used.

yep 3 full 360 rotations. lines are new, clunk was taken out once, but taken care of, put back in without damaging it. will check it again. dont think its the issue, but will do anyways.

it doesnt really do the 4stroke burble sound. I just need to do the pinch test and see where it is at. might take motor off and put on the test stand.

DarZeelon

As David also wrote and [link=http://www.osengines.com/faq/product-faq.html#q2]OS says specifically[/link], one gotta be outa his mind to use all synthetic, American made fuels (except Cooper's Ester based oil) in an AB(X) engine...

This has repeatedly been proven to be a problem.

I you don't overheat your engine, you will not get any of that brown stuff on it either, even with all-castor.

It is your engine's life insurance, as well as its livelihood.

If your engine is cowled-in, remove the cowl, or add internal baffles that will force air to flow over the engine.
Otherwise the air will take the easy way out, without caring that it is supposed to cool the engine...

rainedave

My Feedback: (1)

I use Power master 10% which has an 18% blend of castor and synthetic. I add an additional 4ozs of castor to each new gallon. My planes are a little messy at the end of the day, but because I don't run my engines leaned out to peak rpms I don't have castor varnish issues. More importantly, if something happens to a fuel system in flight and an engine does go lean the odds are it won't be damaged (if I land right away).

David

JoeyCoates

Ok, I am one of the guys who answered your other post, I had the 55ax in a Funtana until my Funtana had a rather abrupt meeting with a Twist about two weeks ago. Here is what worked, period.

#1. This Dar Zeelon character who has answered some of your qusetions here...LISTEN TO HIM! I followed his break in method to a "T" and he knows what he is talking about. I now have one screaming ass 55ax due to following his procedures for break in.
#2. You really need to use a fuel that has some Cator in it, I use Morgan Omega as it fits the bill perfectly. Yes, I use Wildcat CY 30% all synthetic in my heli's as that is what they like, but in a cowled ABC type ringless engine you NEED the protection that Castor gives you. I will admit that my 55ax has some brown castor varnish on it, most likely due to it getting a bit warm while hovering even though I run it a bit rich, but it still runs like a bat out of hell because that castor does its job when the going gets hot. I think that my main needle was at around 2.5-2.6 turns.
#3. For the Funtana you might want to try an APC 12.25x3.75 (worked the best for me) or an APC 13x4W. I know that some people say to load this particular engine down some, but that 12.25x3.75 turned 14,400 on 15% Morgan Omega and the verticle performance was outstanding!
#4. I tried a pitts style muffler as have several others. I have only seen where one person got it to work seemingly well on this engine, but overall they have not worked well. I do not know why, it's just that way. I ended up using the $15 Tower 46 muffler to get my performance. I also picked up 900 RPM's over the stock 55ax muffler by doing so. To get it to fit I cut out a muffler tunnel where the firewall sloped down (you have the Funtana so you will know what I am talking about) to get it to fit. It was a little bit of extra work, but it works well. By the way, I tried a Du-Bro muffler extension on the Tower muffler to get some of the mess away and even that little bit of extension affected the engines performence so it does seem to be pretty sesitive to muffler back pressure.

I understand why you want to use the pitts style muffler, it just looks very clean on this airframe. That is the same reason that I tried it, but eventually you will have to decide between performance and looks, I chose performance. If you build the muffler tunnel though it does keep either the stock muffler or the Tower muffler pretty tight and it still looks good. I just decided to live with cleaning the airplane after flying, it is a bit of a mess at times, but I really wanted the ability to pull out of bad situation which it did in spades. On a side note I did get a bit better performance out of the stock muffler by pulling the baffle out, but it still did not compare to the $15 Tower muffler.

Rcpilot

My Feedback: (78)

The 12-6 is too much prop. That will cause an engine to overheat everytime.

We have one of these engines on a students plane this year. I did the initial running in on the motor with a Zinger 11-7 prop. I had to dig that out of the truck. He had a 12-6 prop for it. Thats a .60 size prop. LHS probably sold it to him.

I gotta say, after running 3 tanks on the ground and then flying it on the 4th tank, I'm not all that impressed with the performance. I've since put 5 or 6 tanks through that plane while training this student. Still not impressed with the performance. I had the low end a little rich for the first 3 or 4 flights, but have since leaned it for a nice transition and rock solid idle. High end is 400RPM down from peak.

It starts on the first flip--everytime. It idles well. It will sit there and idle a whole tank without skipping a beat. It transitions well. Hit the throttle and it snaps to attention without any burbling or hesitation. Runs great. But it's no powerhouse. Mild sport engine at best.

Sarosh

Just ran some tests today after work with the cowl off, using stock muffler and the 1.5 inch extension, i found it to run the best at 3turns out, when i pinch the line it revs up rapidly, i kept turning in the needle until it no longer revs up, and then turned it back around 1/4 turns, ran it at full throttle from there, rpms read 12300 to 12400 rpm. then i let it idle for long period, i wanted to empty the tank, then decided to rapidly advance the throttle to full, and read the tach, it was holding it at around 11900 to 12000. Idles at 1800. seems to be running fine. runs the same as with cowl on. i am going to the field most of the day tomorrow, and also pick up new different fuel, one with castor. The hobby shop where i bought the plane from also the engine from, he recommended the engine to me because i was not interested in the expensive Saito engine at that moment. he recommeneded the 13x6 prop which i broke it, so now its running 12.25x3.25 (sorry was wrong on the size at first place in my previous post)

Also he recommended the cool power 15% which is the exact same fuel i use for my OS 50SX-Hyper in my Raptor heli. Runs excellent with that engine, lots of smoke for the heli, but barely visible smoke with the 55ax engine. Hopefully my lhd has the right fuel i need. The LHD here, 2 of them, all are pointless shops. dont have anything in stock really... so i usually have to head out to the Twin Cities(2hr) or St. CLoud(1hr) to get some parts and stuff.

I decided to peak out the rpm on the engine to see where it peaks off at, it peaked around 12800 to 12900. but at that point, when I pinch the fuel line quickly, it does not do anything, and holding it little longer will drop rpm.

Now i need to fix the hortizal stablitzer support rods, i broke them from my foot holding the plane from taking off!

I am seriously considering getting Saito pretty soon, because it seems to be the best choice from what i have read around RCU, and other reviews. Just not so sure what size to go for yet. Plus i have been drooling on the Katana Extreme from ultra. but have read that Ultra is not being responsive for long time.

DarZeelon

The .50SX is a ringed engine...

While I recommend that ringed engines too be run on fuel that contains a reasonable measure of castor oil; for AB(X) engines I see it as absolutely imperative!

Please post a couple of photos of the cowl you have... It seems the immediate problem you encountered, was overheating.
You did not make sure there is a positive cooling flow around the engine's cylinder and head.

It isn't enough to provide a entry hole and an exit hole... Air must be directed, if necessary, using baffles glued to the inside of the cowl/engine compartment, so that as it is thrown into the cowl by the prop, it flows only toward and around the cylinder and head, before being drawn out, through a twice-trice as large exit, at the rear of the cowl.

Even hundreds of CFM flowing through the cowl, could still leave the engine overheating in stagnant air, so flow must be forced over the engine.


You're lucky it is still with us...

XJet

Another thing in respect to fuel and engines -- heli-engines tend to be run very rich so can get by with a *liberal* dose of what passes for synthetic in most fuels.

Most airplane engines however, tend to be run much leaner so that little bit of castor is *very* important -- especially with ABC/ABN engines where the fit of the piston in the bore is *much* closer and therefore the lubrication is far more critical.

I often hear people telling me that they've run CoolPower straight synthetic oil in all their engines without any problems. It often turns out however, that these folks also think 100 hours of engine life is *lots* -- whereas I tend to expect (and inevitably get) two or three times that out of my engines, possibly because I use a little castor in all my fuel.

speedster 1919

My Feedback: (3)

If you were to get a Saito the 72 or 82 would be the standard set up. Your initial problem is the 13x6 which is a high RPM 91 size. I would not rule out the OS 55 yet till you find the right prop. The 12.25x3.75 is the perfect 46-50 size. Hobbytown or Wildcat 18% total oil with a 80/20 castor mix will be good. The MAS 12x5 K blade should be a good choice. A little more speed with some good pull. If you already have plenty of cool power just add some castor to it. I think Brainard has a race track so castor can be bought at local speed shop or Kart shop without having to drive 2 hours. Even drug store might have castor oil.

blw

My Feedback: (3)

W8YE and I opened up a Saito that had been run extensively with drug store castor added to the fuel. The insides were new looking. No castor film anywhere and no rust. The bearings went, but not due to rust. We were surprised at how clean the engine was.

Cyclic Hardover

My Feedback: (3)

First off there are no temp specs for glow engines. Taking a reading does not do a thing. 99% of the time, if the engine does over heat, it wil be in the air and its too late. Pay less attention to that idiot temp gauge and get it dialed in right and you should be fine. If an engine comes with temp specs, than great but i have yet to see one, otherwise, temp gauges are the #1 sucker buy.

Sarosh

Thanks guys, you all have been very helpful! Yesterday when i did test runs, i didnt use the temp gun to tune it. only pinch method and tach, and found it to run best at 3 turns out. i guess i was trying too hard to get to near the 1.5 range and 16000 rpm, before because i was thinking of the specs on the engine is what its supposed to be at, but like said its only marketing advertised spec. So i will have to live with the set up it runs at now. Also get some castor for my remainder 1 gallon unopen cool power. But i think i am going to the lhd here in town to see if they have any castor blend fuel before i mix this gallon with castor yet. I still fly the heli.

If i were to mix, what ratio should i use? Is there a known specific fuel that works the best with OS engines in case i see it in the store.

DarZeelon, I'll try and get some pictures of the cowl today.

I am going to go shopping today and fly it without the cowl today, see how it goes, maybe put it aside after a flight or 2 and fly the heli which i have not flown in couple weeks. There is abstousley no wind today!!

Speedster 1919 yea Brainerd International Raceway is what we have here, plus some other motorsports tracks. I am not sure if these shops are open today. its off season and saturday. I will check into them though. Also i have been looking into Saito 92 and 100, seems to be the best choice for climbing performance.

pilotpete2

Hi Dar,
Very good points.
I just wanted to add one comment related to baffling and that is, not to open both air intakes on the typical cowl with a side mounted engine, unless of course it's an opposing twin[8D], doing so is guaranteed to reduce airflow over the cylinder with the typical single. I see this all the time with fellow fliers.
Pete

DarZeelon

Thank you, Sarosh.

The so-called 'specs', aren't... They are just claims made by most engine manufacturers, to make what they are selling appear better then what the other guys are selling...

As they come; i.e. with the stock muffler and on the recommended fuel, virtually none of them are capable of standing up to those claims.
One example with the OS.46AX, even with the muffler baffle removed (which should give it some power advantage), this engine can spin an APC 'toothpick' 8.75 x 8.25 NN pylon racing prop, at just over 16,000 RPM, on 15% nitro fuel.

This engine is rated by its manufacturer at 1.65 HP at 16,000 RPM, but this toothpick spun at this RPM equated to only 0.89 HP.

Adding nitro to the maximum recommended 20% nitro will not make up for the 48.5% power deficit...
In fact, if this engine spins a larger prop, like a 10x6 APC @ ~14,300 RPM, it is making MUCH more power; 1.1 HP to be specific.

It shows the engine, as it comes, is not designed to even be spun at the manufacturer's claimed RPM range...

Much like using the 'bozo-trap' IR thermometer, trying to prop your engine to see the 'manufacturer's claimed performance' is a waste of your precious time...

DarZeelon

That is correct, Pete.

Another poster in another thread, about two weeks ago, encountered a similar situation.
I suggested that the 'open' cowl intake (on the right-hand side of the plane) be masked closed with a 'dummy cylinder', glued to the front-inside of the cowl.

Only air that 'actively participates' in the cooling process and thus is accordingly directed to achieve this purpose, should be allowed to enter the cowl. It should also be routed out as efficiently as possible.

Although glow engines do achieve a good amount of cooling from the methanol's 'latent heat of evaporation' (and that of nitromethane too), a consistent flow and exchange of air is also required.

Sarosh

yea, they should state what prop they used but oh well.

thats kinda disappointing though, but i will live with it. I got Sig Champion 15% today, that was all they had in stock. its 1/2 castor 1/2 klotz.

DarZeelon

Sarosh,


That is excellent fuel. The PowerMaster GMA is even better, at 22% total oil.

Both are 50-50 castor-synthetic.

da Rock

Or do this..............