AndresAM

I have already put a galon of fuel trough my DA50 . The engine runs flawlessly, It starts easy (When I don´t mess up the procedure), It has fast transition, a very low and reliable idle and very good power. However it makes an strange loud pop noise during flight only. I have adjusted the needles and because how the engine runs I believe they are OK.
What do you guys think is the reason for the pop noise. I was told it should go away as the engine breaks in but it is kind of annoying. I don´t think I have an air flow issue with the cowling because the engine behaves well not matter if it is inverted, in knife edge or any other attitude.
Could it be too rich or too lean in the low end ...?
Thanks,
Andres

b-mccor8

My Feedback: (3)

low end needle settings are just that used at low end, they work into transition at mid range. High is also just that, used at top end and worked into at transition. Your popping noise as long as you have not overleaned the engine which if it runs well you have not, is completely normal. I believe the DA manual even states this. It takes three to four gallons before it gets better or even goes away. By the way enjoy the noise it screams out in the air HEY I Am A DA.

Antique

My Feedback: (4)

A loud popping noise is normal??
And it gets better after running a few gallons of fuel through it ?
A smooth regular exhaust note is all that should come from an engine, other noises are definitely not normal...I don't care who says it is, DA or anyone else......Sheesh....
P T Barnum was right
Breaking in an engine changes nothing, just makes it looser...Vibration levels come from the weight of the internal parts, there is no change in rotating weight with more time on it an engine...An engine might seem to be smoother when the carb is adjusted properly from the CYA rich "factory" settings...
This stuff gets better all the time

RTK

My Feedback: (1)

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AndresAM

Well,
I am lost here. The engine sounds perfect on the ground and it only makes the noise in the air (high speed) so it has to be something related to air pressure in the cowl. Maybe I should try the carb plate modification or running the pressure line inside the fuse. This is my first gasser and in my area there is not a single gasser so I don´t have anything else to compare with.
If the engine was going rich in the air would it make a similar noise?. Now that I think about it, there is some kind or burble (not much) together with the intermittent pop noise.
I appreciate the help.
Andres

BillS

A thoroughly enjoyable post. Thanks. You probably heard the laughter.

Bill

b-mccor8

My Feedback: (3)

Ok so you have no help to offer at any other time other than to try and flame. So here is my response for the clown who has to reply this way to people. Do you even own a Da??????????? This popping sound he expresses is very typical of every da-50 for the reason yes you run it a little on the rich side during break -in. He never stated and vibration problem. After 3-4 gallons of fuel when the mixture is leaned and the high mixture is also leaned the pop will no longer be there. And since you want to get technical MR. Pt And Barnem a engine does not get looser unless it is worn out!!!!!!!!!!!!!!!!!!!! The purpose of breaking in an engine is to get the metal it is made of to heat CYCLE properly keeping a tight piston or ring to cylinder wall expansion to a minimum while allowing a minut room for expansion. Thus a better fit. So the next time you want to offer the only two cents you have available try and help someone not just comment to try and make a fool of only yourself------Brenden

srm99

och
pop noise is its just a bit rich and and fuel is ingiting in larger volume thats all its anoying what i did was adjusted high first then back off 100rpm then adjust low to get a smoth transition .
good luck it should be right mate .

Josey Wales

My Feedback: (61)

Exactly! Besides being slightly rich isnt necessarily a bad thing..I have 30 gallons thru my first one and it still burbles once in awhile but it runs like a champ!

AndresAM

RCIGN, If the sound that I am hearing is not normal I would like to hear what is the source of the noise according to your experience. If you take a look at your post again It does not help at all, instead you just pissed somebody off (b-mccor8).
The purpose of these threads is share knowledge and help people in the process. If you know so much about engines as you probably do the least I expect from you is a helpful post not one that has nothing to do with my question and makes fun of other´s people opinion which is even worst.
I would still like to hear a possible cause for the noise though......
Andres

B-MCCOR8
This is what I was told before. As I said I don´t have any gas engine in my area to compare with or someone to go for help. I will be patient until I get more time on the engine and hope that when I finally lean out the needles the problem goes away.
Thanks for your help.
Andres

AndresAM

OK, Seems I am a little rich now, Guess more time on the engine and leaning out the needles will do the job! If not I will come back here for more help.
Thanks everyone,
Andres

Antique

My Feedback: (4)

Hey Mccord
From one clown to another (and all other engine experts out there)
check out this web site....
www.mototuneusa.com/break_in_secrets.htm
Maybe the guy who answers the phone at DA should read it too
My answer was for Mccord, not Andres...I ALWAYS set the needles when flying a new engine and have never heard a popping noise..And no, I do not own a DA50..I did, however, test one of the very first DA50s, got it from Dave himself, leaned it out properly...NO popping noise...

RTK

My Feedback: (1)

The "popping noise" I assume is 4 stroking. A rough running engine that does not sound smooth, but I would not really call it a popping. If there is a real "POP" you have another problem.
No matter what anyone says, RCIGN1 is right. IT WILL NOT GO AWAY BY RUNNING A LOT OF FUEL THRU IT.
You have to adjust your needles to change a rich condition, if it is 4 stoking. Running 5 or what every how many gallons of fuel thru it will not help.
With modern metallurgy and machining heat cycling is really not that big of deal. Seating the rings over time due to frictions is what you want.
Set your engine 100-200 rpm on the rich side from day one and run it.
By the way, the term "loose", as apposed to women, refers to a very well broken in engine that has many hours on it and is producing max power. I believe the racers use this term.

b-mccor8

My Feedback: (3)

This still means nothing. We do not use combustion and oil control rings in our engines. WE do not baby our engines on break-in. Da gives rec. on there design and testing and years of it. If anyone knows anything about da engines it would be them. If you read this article you would understand that the point I made with you they do also. Engine break in is simply controling expansion rates of disimilair metals. I think anyone can post web pages that have nothing to do with this threads questions? So you posted again making a completely invalid point. But I guess this is what you do. take your own advise and read up son. I do believe I am having a battle of wits with an unarmed man. Brenden

RTK

My Feedback: (1)

Not to sound mean, but there sure is some one that is unarmed. Dissimilar metals WILL ALWAYS have dissimilar expansion rates, even after break-in.

Breaking in is using friction (friction causes heat) to seat the rings and too much heat is not a good thing.

Antique

My Feedback: (4)

A company that has to recall a few thousand engines because of NOT enought testing might just be a little suspect about recommendations relating to break in....

b-mccor8

My Feedback: (3)

now you are starting to understand. Breaking in, (rich) burble more oil and fuel. expansion rates (friction). Seating, less friction= fuel leaner no burble. Now you can see the process.

b-mccor8

My Feedback: (3)

well as far as I am concerned I must admit defeat you seem to know more than a company that produces engines for the top pilots in the world. sells more and better product than anyone else on the market. Let me know what you mass produce and sell; your qualifications and I will be sure to buy my next engine from you.

Josey Wales

My Feedback: (61)

Umm not trying to stir the pot even more but..well.. do you know ANYTHING about who you are insulting here ?

RTK

My Feedback: (1)

Yes, but you said earlier that the burbling will go away with more run time (fuel you burn) and I don't want anybody to think that is so. Only the needles will stop or cause burbling, not more breaking in.

There is one other cure for burbling, THE BOX. But it has nothing to do with needles and is not pertinent to this conversation yet.

RTK

My Feedback: (1)

Then DA must have self adjusting needles.

Antique

My Feedback: (4)

I don't mass produce engines, just make the best ignition conversions for Zenoah engines, a company that has been making RC airplane engines far longer than any other current manufacturer..Zenoah was selling airplane engines when Dave Johnson was still polishing gemstones...Closest was Quadra, seen any of those advertised lately ?..NO Zenoah has ever been recalled for the wrong con rod design or putting the pulse port in the wrong place...

RTK

My Feedback: (1)

OK Josey, Now You have to tell him

Josey Wales

My Feedback: (61)

LOL! Ralph beat me to it..nothing like hearing it from the horse's mouth

BillS

RCIGN1 is absolutely correct in post #2.

It sure did not take long for some who are lesser informed to get their panties in a wad.

No engine is supposed to pop, spit and hiss at you. A “strange loud pop noise during flight” is not OK.

Bill