jasongrff

My Feedback: (4)

I bought a Top Flite ARF and an O.S. 65LA for it. The manuel shows the engine mounted inverted, I don't think I want to do that. I have read alot of bad things about inverted two strokes and have no experiance with it. I have not messed with it yet but it sure looks like there is room to mount it either sidewase or even straight up. Anybody have experiance with this or ideas?

chris923

My Feedback: (53)

Which Top Flite ARF?

Chris923

jasongrff

My Feedback: (4)

T-6 Texan

ram3500-RCU

My Feedback: (221)

Two strokes run just fine inverted. Use a good plug and adjust it properly, and you should be fine. I will say that I'm not a fan of the LA engine. Bushed, it is very susceptible to overheating and damage when run lean. Mounting inverted may actually help your engine rather than hurt its performance. At least with the LA.

opjose

Yup, as ram3500-RCU says... 95% of problems people have due to inverted engines stem from poor preflight...

Either they've left the throttle too open while priming, causing hydro-lock, or they have misadjusted their engines.

Our planes fly just fine upside down once in the air, running on the ground is really no different, except for starting proceedures.

Some people will clamp off their carb supply line, while fueling to further guarantee no hydrolock with an inverted engine...

... a good idea if you do not use a filler that does this for you.

ameyam

Just ensure the tank height is correct with respect to the carb. I had most of my problems on a 75AX for this reason. When the airplane is being fuelled, it usually happens that fuel enters into the carb due to overfilling. Therafter if flows down into the cylinder causing hydrolock. There are several ways of avoiding this- clamping the fuel line etc. I used to connect the tubing going to the engine to that which came from the tank with a small brass tubing piece outside the cowl. You disconnect it while filling and reconnect when you are going to fly. In case you finger start your model, do remember that inverted engines are prone to backfiring, so atleast use a chicken stick or you will have nasty cuts.

Ameyam

ec121

My Feedback: (2)

I had an inverted engine that wasn't much of a problem. Don't prime it. Just put the glow driver on it and start spinning it. It will fire as soon as the fuel hits. I had mine rigged where I could reach the fuel line with a hemostat. I fueled it thru the disconnected carb. line. Finger starting may be a bit more of a challenge, but wear a glove and flip with force in case of a backfire. I also have closed the needle when using a T fitting. Just count the turns and open it back to the same setting. With practice you will get so close to the original setting it won't matter to the engine. To prevent siphoning just don't fuel it until you are ready to fly or leave the needle closed.

ram3500-RCU

My Feedback: (221)

Nothing really changes. You set it up virtually the same. Mount your tank on the center line of the carb just as you do with one mounted sideways or upright. Siphoning will not be a problem if you do. This means possibly re-drilling any holes they may have in the firewall for the tank, to move it down farther. Not a big deal, but as noted, very important. If you can't get it down far enough, simply loop the engine fuel line up above the outlet of the tank, and you will not siphon. Draw will be unaffected.

Take your time tuning it, and DON'T get that LA lean. She will be toast in a heart beat if you do.

I'd consider an upgrade when you can, if I were you. In the OS line, Top shelf would be the AX model. An AX55 would run circles around that 65LA. I saw one pull a Top Flight scale Cessna 310 all by itself (about 20lbs) when the guy got the other too lean and it quit. He landed safely on the one engine after a few minutes of flight getting everything sorted out and the gear down. Even a well cared for used one would be a lot better than a new LA. They will outlast any airplane you put them it, over and over. Just as an FYI.

opjose

To be clear: that really only affects siphoning problems, which can be easily taken care of with proper pre-flight proceedures...
e.g. clamping the line or using a fueler system that shuts off flow to the carb during refueling.

Once the engine is tuned and running there is no problem.

jasongrff

My Feedback: (4)

  Thanks for the insite, I appreciate the help!!

BillS

Look around at the flight field and you will likely discover that most who are having engine problems are running upside down engines. Yes the problems can be resolved. Yes some prefer appearance over simplicity which is perfectly OK.

I prefer reliability and simplicity and flight time over appearance and mount engines in the 9 o'clock to 12 o'clock position. Right side up engines are just easier to tune and keep running properly.

But the mounting options are your choice.

BillS

ram3500-RCU

My Feedback: (221)

Tuning is definitely taken too lightly and often rushed to "get it in the air", usually for short flights.[] Can't say it is cylinder orientation as much as how it is set up, fueled, and tuned. I see guys constantly fiddling with their engines way too much.

Personally, I do care about looks, being a scale builder, and so most of my engines get mounted inverted. Including 2 stroke, 4 stroke, nitro, and gas. All run fine with no issues when adjusted properly, and none of the glow engines ever require on-board glow. Don't let guys who don't know how to install or adjust an engine convince you otherwise.