Gas engine tuning for newbies....

[jfassino]

mfuess,

Thanks for your reply, and again thanks for a very usefull tuning process.

Jim

[Albatross]

mfuess

Question for you:

BME 110, burbles and hesitates just at the moment when I open the throttle during take off.
I can avoid this hesitation If I do a WOT for only one second just prior to heading to the runway.

I already installed a line going from the diaphragm to the fuselage.

Once in the air, behaves OK. However would hear that "4 strokes" sound when going from high to low.
The needles of this engine seem to be very sensitive.
The engine should have 8 gallons.
I am running this engine on a Boly 27x10.
I am planning to install a mejzlik 27X10.
Flying at 5700 ft ASL.

[Pro1Foam]

Sounds to me your low end maybe a bit rich and/or you have fuel build up on your reed valves. I always do a full throttle rev up just before take off to get rid of any fuel build up on the reeds. My2c

[Albatross]

Thanks
That’s most likely right; the side effect of reducing closing the low end needle is that firing up the engine from cold is somewhat difficult.

Now if I let the low end without touching it, while doing 3D at low rpm, then if I want to open the throttle, saying to go on a vertical maneuver or simply switching to normal flying style, then that hesitation comes along.

May be out of the context, however is just more information about how this engine behaves: I got a dead stick while flying low inverted and at low rpm … needles to say that under such flying attitude all I could do was a controlled crash.

By now the airplane is fixed and ready to go, carburetor cleaned. Gas tank clunk checked out.
I hope for the best next time I take her to the field.

[Pro1Foam]

Do the tuning method in the first post of the thread and your probllem will go away. (Your low end is rich).

What oil are you useing?

[mfuess]

	Quote: Originally Posted by Albatross
	mfuess Question for you: BME 110, burbles and hesitates just at the moment when I open the throttle during take off. I can avoid this hesitation If I do a WOT for only one second just prior to heading to the runway. I already installed a line going from the diaphragm to the fuselage. Once in the air, behaves OK. However would hear that "4 strokes" sound when going from high to low. The needles of this engine seem to be very sensitive. The engine should have 8 gallons. I am running this engine on a Boly 27x10. I am planning to install a mejzlik 27X10. Flying at 5700 ft ASL.

You're slightly rich on the LOW needle. Sensitive needles "generally" indicates a heavy load. (heavy prop) But it shouldn't be a problem though... BME 110 is a very potent engine.

[Albatross]

	Quote: Originally Posted by Pro1Foam
	Do the tuning method in the first post of the thread and your probllem will go away. (Your low end is rich). What oil are you useing?

I am using MOTUL 800 (2T) off-road @ 40:1
Supposes to be the best synthetic oil around for those that practice motocross.

BTW I can´t get AMSOIL in Mexico.

[Albatross]

	Quote: Originally Posted by mfuess
	You're slightly rich on the LOW needle. Sensitive needles "generally" indicates a heavy load. (heavy prop) But it shouldn't be a problem though... BME 110 is a very potent engine.

That´s a good point, I made a test running the engine that I used during to break-in period for the engine, that is a BME Prop 26 x 10. The rpm where up to 6800 or more if am not mistaking, however I ony teseted it for couple of flights, looks like it handle the transitions better, as far as I recall. I never repeate the experiment ever since.

We are few around flying BME110, however a friend of mine told me that the 27 X10 should de the prop for this engine, even at this ASL ( 5700 ft plus).

I am ready to try: 27X10 Mejzlik , and 27 10 Vess. However I will try the 26x10 as well.

thanks !

[mfuess]

The problem with field testing 27" props is the price one has to deal with.

[aspicer]

Mark, my DA-85 is tuned using your method and works great. The one little hicup is that when transitioning from full throttle to idle quickly the rpm dips below normal idle by a couple of hundred and then comes back up. So,normal idle is 1500, go to full throttle and pull back to idle and the rpms dip to 1200 then come back to 1500. I'm afraid that i'm going to flame out on landing if I don't fix it. Any ideas what I should be looking at or is this normal?

Thanks.

[mfuess]

	Quote: Originally Posted by aspicer
	Mark, my DA-85 is tuned using your method and works great. The one little hicup is that when transitioning from full throttle to idle quickly the rpm dips below normal idle by a couple of hundred and then comes back up. So,normal idle is 1500, go to full throttle and pull back to idle and the rpms dip to 1200 then come back to 1500. I'm afraid that i'm going to flame out on landing if I don't fix it. Any ideas what I should be looking at or is this normal? Thanks.

Actually this is normal but you can eliminate that by having TWO idle speeds programmed on a transmitter switch. You should have a FLYING Idle programmed at around 3000 RPM, and a LANDING Idle programmed around 1500 RPM. When the aircraft is in the air use the FLYING Idle. When you are ready to land then switch to your LANDING Idle.

[RMaia]

GREAT and AWESOME info in this thread!!

mfuess, it's a wonderful thing you actually taking the time to answer all questions. Truly a contribution to the hobby.

I've already got a DA 50 as my first gasser, and I should be ready to run it soon (still need to start building the plane for it) but I got a question... You say to shrink off all glow engine thoughts from the head when dealing with a gasser, and my concern is the break in. By logic I'd guess the glow principles won't apply, but then, what principles will?

Talking with a buddy he said just use more oil the mixture (as per the manual) and forget about a
"special" needle setup for break-in. Tune it like you would if the engine was already broken in and fly. Is that correct? Can the tuning method you described be used for the very first runs of a DA 50? Or better leave he factory settings for the first few gallons (even it it doesn't run great)?

[mfuess]

	Quote: Originally Posted by RMaia
	GREAT and AWESOME info in this thread!! mfuess, it's a wonderful thing you actually taking the time to answer all questions. Truly a contribution to the hobby. I've already got a DA 50 as my first gasser, and I should be ready to run it soon (still need to start building the plane for it) but I got a question... You say to shrink off all glow engine thoughts from the head when dealing with a gasser, and my concern is the break in. By logic I'd guess the glow principles won't apply, but then, what principles will? Talking with a buddy he said just use more oil the mixture (as per the manual) and forget about a "special" needle setup for break-in. Tune it like you would if the engine was already broken in and fly. Is that correct? Can the tuning method you described be used for the very first runs of a DA 50? Or better leave he factory settings for the first few gallons (even it it doesn't run great)?

Breaking in ANY gasoline two stroke engine isn't exactly Rocket Science. The only part that needs breaking in is your piston ring, that's it... So with that in mind, use a little more oil in your mix if you like. My philosophy is very simple, if you break-in a DA-50 on 32:1 ashless oil and it runs great, why bother to change it? I have around 200 flights on my DA-50 and I'm still using the same gas/oil mix I started with. My engine always starts easy and runs like a top. I haven't touched the tune since day one!

Don't get yourself all caught up in the "opinions" of switching to synthetic after break-in. There is no reasonable foundation for it. If you happen to like (for example) Pennzoil 2 stroke oil, break-in at 32:1 then maybe reduce it to 40:1 later on. If you want to switch to synthetic you certainly may if you like, but its not necessary.

Keep it SIMPLE!

[RMaia]

	Quote: Originally Posted by mfuess
	Breaking in ANY gasoline two stroke engine isn't exactly Rocket Science. The only part that needs breaking in is your piston ring, that's it... So with that in mind, use a little more oil in your mix if you like. My philosophy is very simple, if you break-in a DA-50 on 32:1 ashless oil and it runs great, why bother to change it? I have around 200 flights on my DA-50 and I'm still using the same gas/oil mix I started with. My engine always starts easy and runs like a top. I haven't touched the tune since day one! Don't get yourself all caught up in the "opinions" of switching to synthetic after break-in. There is no reasonable foundation for it. If you happen to like (for example) Pennzoil 2 stroke oil, break-in at 32:1 then maybe reduce it to 40:1 later on. If you want to switch to synthetic you certainly may if you like, but its not necessary. Keep it SIMPLE!

Thanks a lot!!

Yeah, I don't want to bother with the needles if it runs right since the first start, but my concern is if it doesn't run right and I need to do some adjusting. In this case, it will be fine then to tune it up for "peak" right away on the very first tanks? I just want to know if I won't damage the engine by doing that. Won't be pleasant to damage it right in the first tanks due to misuse....

I like the idea of keeping it simple! There's a saying which I just loved which goes by "Simplicity makes efficiency easier".

[mfuess]

Tuning for peak performance is OK from day one. There is a fine line between peak performance & lean. Just don't go too lean.