vertical grimmace

My Feedback: (1)

I have a Saito 180 installed in a BUSA Fokker triplane. Originally I had it mounted directly to the firewall and it ran absolutely perfect. I have a 20-6 prop and I run 20\20 fuel. This setup seemed to prove itself. After having the engine now for several years I have begun to notice a lack of power as the flight goes on. It is OK at first but it acts like it is going too lean. Even trying to richen it up has not helped.
I had made one change, I wanted to add a more scale looking cowling and to mount it properly I had to "box" the engine mount back into the plane. This moved the engine back 1 5\8" from it's original location. Could I possibly be starving the Carb of good air in flight? I am running on board glow. It is the Nelsons product. I do not think this would have any effect though. Any suggestions would be apreciated.

alan0899

G'day Mate,
I think cooling is your major problem, more air in & 2 to 3 times more air out.

vertical grimmace

My Feedback: (1)

Most of the cylinder is hanging down outside of the cowl. I actualy have more cylinder in the air now than I did in the initial setup.

yallaair

Have you checked the spraybar in the carb? Can be some dirt in the nozzle! Also check the fuelfilter (If you are using this). I have seen that the small fine filters are getting easily clogged with same results as you describe. Also check your tubing, can be an airleakage or just a tank problem. As long as you have fuel, comp. and a working glowplug, everyting should be OK.

B.E

rc-sport

My Feedback: (12)

Check the gaps of your rocker arms, I bet those have moved. The same scenario happened to me and that was the problem

stelios

My Feedback: (4)

What rpms are you getting with this 20x6 prop?

Stelios

flyinrain

My Feedback: (25)

I'm surprised it worked with that big of a prop. It would seem the engine is being overloaded. Try a smaller prop and get the RPMs up a bit. Should be around 9000rpms

NM2K

My Feedback: (14)

Cooling was my first guess too.

Naturally, you have checked all of the silicone fuel lines both inside and outside of the fuel tank, right? A crack in one of these, or in the brass feed pipes, could explain the engine going lean without the ability to be corrected via the needle valve being richened.

If you ever got off the ground with the engine leaner than it should have been, you could have caused the ring to lose its tension (via overheating), which will reduce power output and fuel draw, which will further overheat the engine if you're one of those "number of turns" folks that religiously sets the needle valve to a certain number of turns that worked once back in 1953. <G>

Most "engine problems" are usually problems with the ancillary equipment, as you probably know.

Good luck.


Ed Cregger

asmund

20-6 is a really big prop on that 180. I use 17-6 on my 180 and get 9100 rpm, you must be down in the 6-7000 rpm area somewhere. My guess is that you overload your engine and it gets too hot

Hobbsy

My Feedback: (102)

That's a prop for the 2.20.

vertical grimmace

My Feedback: (1)

I have been flying this plane for 3 years now and the 20-6 prop is perfect for the aplication. This is a WW1 scale aircraft that flies at 1\2 throttle most of the time. I am not trying to do hoverbatics. I am trying to maintain a 35-45 mph flight speed.
I will have to go through the tank again I think and pressure test my lines, but I was wondering if the caberator being back in that box is getting bad air? I was tinking of adding a hole so air could pass through.
I did check the valves and they seemed OK with the provided feeler gauge but I may have not checked in the right spot. I have never adjusted those before.

gjeffers

20x6 is still to much prop for the 180, a 18x6 will give similar speed and unload it a bit.

Hobbsy

My Feedback: (102)

Gary, Brian Cooper is waiting on a shipment of the GloDevil plugs, if interested find a post of his and click on the E-mail box.

Pepe J

My Feedback: (2)

Can you post some pic's of your engine installation?

You stated, " I have never adjusted those" regarding the valves. Valve lash almost always has to be adjusted after the first few tanks at break-in. Do a search here at RCU if your unfamiliar with the procedure to make sure you have set them correctly.

I agree that 20 x 6 prop is to big, but if you're just putt'n around at half throttle, it sounds like you can get away with it like you have for the last three years. How much time / fuel do you have on this engine with the 20 x 6 ?

Is there or has there been any detonation with that large prop?

I'm thinking maybe that big hunk of lumber you're swinging is starting to take it's toll on your bearings.

vertical grimmace

My Feedback: (1)

Here is a photo. Can't really see the firewall but this is the onlt one I have at the moment.

Pepe J

My Feedback: (2)

Nice looking ship.... I can see why you have the 20" stick on there.

I can't see the engine overheating from lack of air flow, but the symptom's you describe sound like it could be a heat problem from bad bearings? Have you noticed any "Knocking" at all? If so, I would tend to point a finger at the bearing's.

At this point, check your fuel lines, valve lash etc. as suggested earlier. Also, and I see this all the time at the field. Tanks are filled full then the needles are adjusted. The majority of the guys have a flame out at half tank and they wonder why things went lean? I do all my needle adjustments with minimal fuel in the tank. After that, the only thing that can happen with a full tank is that the engine is going to run slightly rich.

I use to run an 18 x 5 on a 120. The symptom's you describe were similar, but I had a slight knock at WOT. Turned out the bearings were heading south!

gjeffers

thanks Hobbsy, ill do that!