F4u5

My Feedback: (81)

My plan is to mount this on a BUSA Stearman, PT17 style, so nice for show and no cowl/baffeling to deal with. Thx Scott.

Jeff

Edhamp

Well I flew my carf Corsair (detailed on another thread) with the EVO160. It flew the 50lb model with ease. However, the engine suffered from gradual loss of revs about 2-3 mins into flight at full throttle although it never cut (phew!) and still flew the model around at reduced power. I am putting this down to overheating under load and hope this will improve with baffling the engine, something I did not do because I never had any overheating problems with it on the ground fully cowled, but obviously prop not under any load. Perhaps a mistake?

The heat build up seems to be around the gearbox (is this normal?) the cylinders still being cool to the touch after landing. Also turning it over by hand soon after landing showed the engine to be free with no indication of tightening and would run perfectly again on the ground and produce max revs so hopefully not a mechanical issue.

Lots of dirty black oil exhaust stains on the model after flight, something others have found and not unusual with some engines.

The engine has had several tanks fuel at 32-1 oil mix (Belray H1R) before switching to 40-1. Prop used was 26x 14 and 26x 12 (5700 rpm) THREE BLADE. The 26x12 performed better.

Maybe a TWO BLADE will also help to reduce some of the load on the engine and is something to try if baffling does not work or is it just asking too much of this engine? Is this classic tightening of the engine due to overheating caused by poor airflow?

Ed

Maxam

My Feedback: (62)

Ed, congrats on the first flight! It is good to hear that while the engine was strong you had good power. Yes the crankcase will store the heat and stay hot longer.due to a lower surface area to mass ratio. Moki's do the same. If the cylinders were not that hot overheating may not be an issue. Do you have an infrared pyrometer? They are inexpensive and very helpful. Cylinder temps should be below 210 F. Lets say overheating isn't the issue. Is the engine leaning out on you? Check the Y tubes from the exhaust to the carb. Are they clogged with oil? If so the pulsing action my be compromized so the carb looses pumping effectivness. Concerning props. On my Beast I used with great success a SEP 28x14 two blade. Your RPM,s I would consider to be on the high side. I like to load the engine on the ground to under 5000rpm. Let me know if any of this helps. -Tom

Edhamp

Thanks Tom, very helpful. I had not thought about the Y tubes getting clogged. I,ll check these along with everything else. One symptom that may point to carburation rather than overheating (on which the jury is out if as you say a hotter crankcase is normal) was that the revs did temporarily recover after about 10s if I bought the throttle back after losing some power, only to go off again on increasing throttle. Surely if it were overheating then more likely the engine would stop?
I had 4700 rpm on the 26x14 3 blade prop (quite a thick blade Beila). It flew fine with this also (first flight), I just thought I was not helping with the extra load so switched to the 26x12 second flight which I thought gave better acceleration).
If I can crack this problem, then it is a very nice engine/aircraft combination, comfortable to fly without worrying about overpowering and stressing the model. Off course, nice scale props are out of the question!

Link to the other thread
http://www.rcuniverse.com/forum/m_11...m.htm#11471536

I ll upload some pics when the system allows

Ed

Maxam

My Feedback: (62)

Ed, Your symtoms suggest the high speed needle is too lean. Try opening an eighth turn. -Tom

Edhamp

Tom definitely agree that is also something else to try, currently I am exactly two turns open on the high needle (manual suggests 1.75 as a starting point ), I found the engine rpm on the ground is not very sensitive to changes in needle setting (as you might expect in comparison say to typical gas engines), some trial and error may be necessary to get the best in flight.
Ed

Maxam

My Feedback: (62)

Ed, can you make the engine go rich at full throttle by further unscrewing the high speed needle? If not then the carb is not pumping adequately. Definitely clean out the pulse tube like I suggested. You might need to clean out the pumper side of the carb too. My prototype 160 had a different carb that did not pump fuel well so I started using a fuel pump. This should not be necessary with your carb though. Are you using large ID fuel line and clunk? Short distance from the fuel tank to the engine? etc. etc. Yes I know...many thoughts! -Tom Sure hope one of these ideas fixes the problem.

Edhamp

Will do and check all this and report back. I am using large bore fuel pipe, felt clunk and the tank sits high in comparison to the carb with a short, approx. 6" and at least on initial set up it was possible to make the engine go rich by opening the needle, . Thanks again . Ed

codiddley

My Feedback: (4)

I've read elsewhere that a fuel pump may help these engines. Has anyone else had similar experiences? Last year at WOTR a local had a beautiful award winning 1/3 BUSA Stearman with the 260 on the nose, and the damn thing flamed out on him. He clipped the fence off the end of the runway and ended up breaking his airplane in half, and he had no idea why it shut down. I heard it lost power before shutting down, so maybe it was also a lean condition. I read most of this thread, and between the whining about engines not fitting in some peoples planes I may have missed what kind of carb is being used? Is it a Walbro? Tillotsen?

I'm planning on using this engine in a 33% AMR Waco as well, and after the investment in time and $$$ I'm very cautious about reliability.

Maxam

My Feedback: (62)

It is a Walbro. My prototype 160 did benifit with the use of an APS fuel pump from Vogelsang Aeroscale. My understanding though is these engines with the final carb type have good fuel draw. Please run and familiarize yourself with the engine before flight. There are many things as we all know that can make an engine go lean. Maybe his engine was lean in the first place and overheated. Was his filter clogged? etc etc. Yes my 160 ran great with the fuel pump in a Hangar 9 Beast untill it crashed due to a...........failed fuel pump!!!! How's that for luck. Yep they replaced it but not the plane! It was the only fuel pump they ever had fail. -Tom

codiddley

My Feedback: (4)

Thank you for your reply. I will definitely do some bench testing and tuning before it goes on the nose of my plane!

I'm sorry to hear about your troubles! As soon as I thought "Fuel pump" the words "Point of failure" entered my mind.

Another silly question- I read in the specs that the rings are hardened steel. In my experience hardened rings make for much longer break-in, and less power overall. I have Bowman rings in a few of my ~100cc 2 stroke aerobatic motors and they consistently gave me a 2-300 RPM gains almost the first run. I would hate to tear apart a $3,400.00 radial for something like new rings, but it does make me wonder why hardened steel?

Maxam

My Feedback: (62)

That sounds like the advertising department! Pete might clear this up. They where easy to compress with my fingers when I was reinstalling a jug one time. The engine will turn freely after a few runs. You can tell when the plugs are removed and then turning the engine over. Keep writing. A question is not silly if you don't know the answer.-Tom

Pete Bergstrom

The term "hardened steel" is a relative term as there are many grades of hardness. Yes, the harder the ring, the longer it takes to break in because it wears slower. The instant 2-300 rpm increases you mention might be attributed to a softer material seating sooner and the efficiency of the engine improving when they do. I don't have any idea how hard the Bowman rings are but I have not heard any comments referring to our engines as being difficult to break in. I don't suggest you Pre-emptively replace the rings based on an assumption that the supplied rings are "too" hard.

Pete

Edhamp

I have had a chance to inspect the engine and can confirm that the loss of power I experienced at higher throttle is not due to any fuel issues I can find. The pulse tubes were not blocked (the plastic pipes used had hardened so I have changed to tygon), pumper side of carb also clear. I doubt the engine has been running lean, the plugs colour do not show signs of lean running, if anything too rich, and both needles on the rich side of manufacturers set point. The engine has always run perfectly on the ground, including prolonged running at full throttle. I also think that a fuel pump is not really necessary with this carb unless you have really long fuel lines, the draw is very good ( in fact the one time when I forgot to open the tank air breather , the engine never faltered despite having to suck fuel from a sealed tank and only stopped after half the tank had been emptied creating quite a pressure drop) Valve clearances also checked and all within tolerances. It all points to overheating and fitting baffling which I have now done (maybe I should have done this in the first place if I followed the advice in the manual!). I do not think the air outlet side is an issue as you can see from the photo there is plenty of area. Of course, I will not know if this has worked for sure until the next test flight.

Pete Bergstrom

The two pressure tubes going from the intakes to the base of the carb are supposed to be very stiff and hard. That is the way they are supplied. If they are not stiff and hard but soft like tygon the tubes will actually collapse and not allow the negative pressure to get to the carb. Please put the old tubes back on.

Pete

Edhamp

Thanks Pete , I appreciate that fact and I used the thin bore thick walled stuff, not the type that softens. I was concerned that the originals may not be air tight being so hard. Once they are removed for cleaning it is unlikely they will go back and remain air tight. It looks like hard fuel festo tubing to me which I can replace as per original.

eness76-RCU

My Feedback: (13)

I'm considering the 160 for a GS project. Are guys needing an electronic fuel pump with the 160? I saw the posts about the prototype, but was interested if guys with production models are finding they need it? Thanks.

Maxam

My Feedback: (62)

Eness, You should not. Like the other gas radials, set the full throttle setting to 3/4 or less opening. Frankly the choke area is too large. You will lose no power and have an excellent running engine that is easier to tune. Learned this from the Germans who run a lot of radials. -Tom

Edhamp

The fact that this engine EVO160) does not run or tune properly with the throttle fully open (because quote the choke area is to large unquote) has exactly been the cause of my problems in my CARF corsair and explains the symptoms of leaning out at full throttle and recovery as the throttle is reduced, presumably as the fuel draw cannot keep up with demand. The problem is exaggerated in the air under load with increasing fuel demand. It may well be the engine works best at 3/4 throttle opening and hopefully still develops enough power.

So what are we meant to do? Limit throttle movement on our radios, fit a throttle stop to the engine? Are throttle stops now fitted to these engine to limit throttle opening to around 3/4 so as to reduce the risk of the engine stopping in the air? Should I fit one to mine?

This workaround to avoid pumps etc may be OK if you are certain we are still getting the power delivery advertised for these engines. Not a problem if you have an model with a 250cc radial and power to spare, but there will not be many sub 50lb warbirds that will take an engine the size of the EVO160 so you will need every one of the claimed hp's.

Why not fit the correct size carb in the first place?

Maxam

My Feedback: (62)

Ed, It might be the availability of Walbro carbs. Seriously just limit the upper travel of the throttle servo with your transmitter. No need for a throttle stop. You will actually gain power! (after readjusting the screws) Limiting how far the butterfly opens effectivly decreases the choke area. My 160 adjusted to 3/4 opening made the engine run great with full power. Sure flew the heck out of the Beast! My Moki 215 is adjusted to 5/8's open and I have tremendous power. Just try this and I think you will be pleased. -Tom

Edhamp

Tom, Just heard from Horizon UK who checked their current stock of EVO160 and they are all fitted with a throttle limiter plate on the carb and so they are sending me one (my engine was one of the first into the UK and dose not have it). I know I could do it on the radio but this avoids any risk. Hopefully I will have better luck and be able to tune more easily. Ed

Maxam

My Feedback: (62)

Ed, That is interesting and great. I am confident you will be happy with the results. You will also get better midthrottle running qualities. -Tom

F4u5

My Feedback: (81)

So, I finally did pick up a 260CC radial from Evolution. now, I have to find a project to fit it onto. Static thrust output would be beneficial information. I'd like to know just how big a plane this 7-260 can pull.

Jeff

reyn3545

OK... I spent about six months with a Moki 150.. replaced the ignition system and finally had a very smooth running motor, but it just wasn't big enough. That motor's for sale here now, and today I ordered the new project... a CARF Pitts S12 and the Evolution 260. Motor should be here next week, and the plane will probably be mid-November. Can't wait to get started with it!

reyn3545

I do have a question about the exhaust collector ring... why would they put the smoke injector almost at the bottom of the ring? Wouldn't you think they would put it at the top so it would have a better opportunity to burn before exiting?