I bought a new Hangar 9 alpha trainer RTF, (I have about an hours flying experience, and can take off and land solo). and I have a problem I need diagnosed. Every time my plane takes off, after it gets about 15 feet in the air, I hear an audible "bang" and then the engine begins to sputter. I am getting really good at gliding it back to earth since this has happened to me 3 times.. in a row! So here is what I've done, which hasn't helped. On the ground, I started the engine back up, let it warm up a bit, then while holding the airplane, I have my wife take the transmitter and move the throttle to high. Then engine still works fine at this point. I then take the airplane, and hold it at the same angle as it would be during takeoff. Still no problems, engine is running perfectly. So then I hold the airplane upside down, at an angle, inverted, everything. The engine doesn't skip a beat. So the next thing I do (with the engine still going like crazy, is swing the entire fuselage left and right (trying to see if G forces are possibly preventing fuel from entering into the engine or something similar. You guessed it (other than looking totally crazy swinging around a running airplane, the engine is still working fine.) So I've shut the airplane off, and took a look at the tank. Everything looks great. The clunk is doing its thing, no bends, I even made sure I had the correct line connected to the muffler, and engine. I tuned the engine doing the pinch test, everything works like its supposed to, the engine speeds up briefly then dies. So, I need some help! On the ground the engine will make it easily through an entire tank of gas at full throttle, but as soon as you try to take the thing into the air, its "bang!" and sputter sputter... you get the picture. ANY advice is greatly appreciated, so thanks in advance! Mitch W. Watertown, NY.

Welcome to the forums!

Do you have a fuel filter on your plane? If not I would suggest getting one. I had similar issues with my trainer. One thing you can try is remove the main needle and then carefully blow on the pressure line to try and clear any trash that may reside in the fuel feed.

Keep us posted on what you find.

Good luck,

VG

Mitch,
You may also be one or two cliks on the lean side and as the engine unwinds it goes too lean.

Cheers

I'll second the too lean thing. Richen it a little and try again.

yea i would say it is lean. As the plane is leaving the ground the air is getting thiner so this makes for a lean condition on the engine. That is why the engine runs good on the ground and not in the air.

Gosh “bangs� come in a variety of different sounds with a variety of meanings. Consider finding an experienced pilot to final check the engine tuning. Someone with the right experience can be extremely helpful and save a lot of repair work and cost.

Bill

mitch a good way to check the low end would be to,and I'm sure you have seen people do this is to place your planes elevator or plane stand in front of the elevators then once its been brought to a good warm up on the engine,nail the throttle and the plane should not stumble nor dye immediately.it should transition smoothly.bring the low end in 2 clicks at a time until you reach the point you need.also if you havent already inspect the fuel line to carb insuring thats theres no air bubbles and the nipple to the carb (fitting) is tight.
good luck and happy flying!

Don't get too complex. Just richen the needle 2-3 clicks and give it a try.

Don't mess with the low speed!!! Just adjust the high speed a bit richer and try it again. ENJOY !!! RED

Make sure the tank is well insulated with foam around it. Sometimes as the engine unloads and revs higher in the air it will reach a frequency that causes the fuel to foam. The mixture of air and fuel in the line will cause the engine to lean out and quit.

Be sure the klunk is at least 3/8" away from the back wall of the tank. If it's too close, it can cause nightmares on takeoff or high-G maneuvers.

Dr.1

Guys, thanks for all the great advice. I took it all in, and I've made some progress. To eliminate any fuel line/tank problems, I totally replaced the tank and fuel lines. I also added a fuel filter between the tank and high speed needle, and another fuel filter on the pressure line between the muffler and tank. (As per the advice of the hobby shop guy.) I also leaned it up a little bit. So I ran it up, gave it a couple minutes to warm up and then took off. The engine didn't die! But now I have a new problem. The airplane started a left bank, and I couldn't get rid of it. I put in full right aileron, and it helped a little, but the plane continued to slowly angle off to the left. So I cut the throttle and let her glide in to some tall weeds, escaping any damage. The plane even cart wheeled once since it had the left bank in slightly on impact. Anyway, the red flag here is this has happened once before when I was learning to solo, and the plane wrecked also. So since I've had so many engine problems, I forgot about the left bank problem. On the ground everything checks out. The rudder, elevator, and ailerons all swing in their proper respective directions. Range check works fine. No wind. Batteries fully charged. No loose servo horns. I'm out in the middle of no where, and nobody else is on the same channel. I can pretty much rule out someone else in the area on the same frequency. So as you can see, I've already thought about most of the obvious causes, except that I am on channel 52. I've heard 2 separate people tell me now that for some reason channel 52 has problems. Has anyone else heard this before? I'm using a Futaba 6EXA transmitter, FM Channel 52. Again any advice on this is much appreciated, and thanks in Advance! Mitch W.

.....and trimming the ailerons while in flight to the right did not correct it? If you are trimmed all the way to the right, and still can't get it trimmed out then you will need to readjust the linkage either at the servo, or at the control surface. I would also suggest you do a lateral balance check, but I would doubt isf the Plane is off that far lateraly. Also be sure you are getting your wing good and centered on the fuselage. I usually put a couple permanet marker marks on the top of the wing that marks dead center so you get it on the same evereytime if using rubber bands.

IMO radio hits are not that common as some may have you believe. When a Plane gets drilled into the ground IMO it is just too hard for some pilots to admit to themselves that a case of dumb thumbs crashed the Plane. So after alot of crashes you will see alot of excuses being made, and a "Radio Hit" is usually one of them that tops the list. I am not saying that it don't happen. I am just saying that I would bet it don't actually happen very often unless someone right at the field accidentally turns on a Transmitter that is on the same freq which is certainly a radio hit.

To make a suggestion make sure that your covering stripes on top of both wings are good and down because if one comes up in the middle it will act like a air brake and pull the plane in one direction and into the ground I had a small problem with mine a while back.

Chris

question. When you test out the plane on the ground is the wing mounted on the plane or is it off to the side so you have access to the inside of the plane. I was wondering if you have clearance for the controls to move when it is mounted tightly on the aircraft. It is hard to figure if I am not there. Is the servo good no broken gears or anything

Yeah, I've made sure that the airplane is trimmed well. Also the wing was attached with rubber bands, and centered. I always do the function checks with the wing on, and all the ailerons move fully in each direction. In the post above, I don't know what "IMO" means, so I'll need to know what that is before I can rule whatever that is out. As for me causing the airplane to bank left, well I guess anything is possible, but I remember having full right aileron in as it continued to bank the opposite direction. Does anyone think it might be the cursed channel 52? Thanks in advance, Mitch

Make sure your horizontal stab is parallel with your wing. If it isn't, giving an elevator command could cause a bank.

Wow, great idea, I didn't think of that one, that is possible. I'll let you guys know what the outcome is.

IMO- in my opinion. There used to be an acronyms list here in the begginers forum, I learned alot from it. As far as your banking problem - how long of a flight did you have? You might just be dealing with P-factor. The torque of the engine at low airspeed will cause the plane to bank to the left. Try keeping the plane on the ground longer and build up more speed before you lift off. Also, since the rudder is in the prop blast and the ailerons aren't, the rudder is much more effective at low airspeed. Try giving right rudder as well as right aileron. Good luck.

radio hits don't cause failure on one function. every function during a radio hit can be effected. if failures occur on 1 specfic function all the time then the culprit if it is not the transmitter continously causing problems then it is usually the reciever or maybe a dirty servo pot because they experience vibration and shocks.