3w 106 initial test run and observations cont.
03-07-2006, 07:29 AM
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3w 106 initial test run and observations cont.
Well finally got the 106 / extra into the air last weekend.
After testing on the bench and some short ground runs I was very happy with the performace of the motor.
On the ground...........engine runs great (is this starting to sound familiar?)
In the air.................it does the same old and OFTEN documented, "goes so rich when you roll or knife edge it almost dies"............!!!!!
Now the engine is a QS series WITH the carb trumpet. If you examine one of these you can see that the trumpet has a large lip on the inside. What I think happens is NOT an airflow problem as a lot of people seem to think. (before I get flamed Im talking engines with the trumpet only here). What Im thinking is that any excess fuel blown from the carb gets caught in the trumpet (because of the large lip) , pools in there........and then temporarily floods the engine when you roll or invert. The fuel may also block the carb diaphram air feed to but Im not certain.
Now..........of course.......if the engine is leaned to the degree that there is no fuel blowing from the carb (and therefore pooling in the trumpet) then the problem goes away..............and so does your lovely new plane when it deadsticks into the ground because you new engines low end is way too lean.
What Im thinking of doing is running the low end slightly leaner and then perhaps drilling a series of small holes around the widest part of the trumpet to try to eliminate any fuel build up....................or just take the trumpet off and resetting the needles to that!!!
ANYWAY THIS IS JUST A THOUGHT.............JUST AN IDEA AS TO WHAT IS HAPPENING..........ANYWHO MOVE ALONG PEOPLE, NOTHING TO SEE HERE!!
kindest regards, IanB
PS KEEP A LOOKOUT FOR THE NEW MTV SHOW........"PIMP MY PLANE"
After testing on the bench and some short ground runs I was very happy with the performace of the motor.
On the ground...........engine runs great (is this starting to sound familiar?)
In the air.................it does the same old and OFTEN documented, "goes so rich when you roll or knife edge it almost dies"............!!!!!
Now the engine is a QS series WITH the carb trumpet. If you examine one of these you can see that the trumpet has a large lip on the inside. What I think happens is NOT an airflow problem as a lot of people seem to think. (before I get flamed Im talking engines with the trumpet only here). What Im thinking is that any excess fuel blown from the carb gets caught in the trumpet (because of the large lip) , pools in there........and then temporarily floods the engine when you roll or invert. The fuel may also block the carb diaphram air feed to but Im not certain.
Now..........of course.......if the engine is leaned to the degree that there is no fuel blowing from the carb (and therefore pooling in the trumpet) then the problem goes away..............and so does your lovely new plane when it deadsticks into the ground because you new engines low end is way too lean.
What Im thinking of doing is running the low end slightly leaner and then perhaps drilling a series of small holes around the widest part of the trumpet to try to eliminate any fuel build up....................or just take the trumpet off and resetting the needles to that!!!
ANYWAY THIS IS JUST A THOUGHT.............JUST AN IDEA AS TO WHAT IS HAPPENING..........ANYWHO MOVE ALONG PEOPLE, NOTHING TO SEE HERE!!
kindest regards, IanB
PS KEEP A LOOKOUT FOR THE NEW MTV SHOW........"PIMP MY PLANE"
03-07-2006, 08:39 AM
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RE: 3w 106 initial test run and observations cont.
I would leave the low end set where it has good transition on the ground and gradually lean the top end. From my experience this is how I cleaned up the transition. Most people try to lean the low end and it is really the high end that is to rich. Just slowly creep in on the high and you should see the transition problem go away.
03-07-2006, 09:36 AM
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RE: 3w 106 initial test run and observations cont.
JPrc is right. My QS106 did the same thing. Its usually the Hi end needle. My engine would not lean out to clean up the mid range till at least 10 gallons. It also had a "very slight" hi speed stumble. If I tried to lean this situation it would start to loose transition. After it gets broken in it'll let you adjust this out. Its a very slight adjustment as the needles are sensitive, it'll be the Hi end needle, keep flying it a tad Hi end rich a lot, it'll like it and it won't hurt a thing, give it time it'll come around.
when it does you'll really appreciate the power these 106's have...My engine took I figure 15 gallons to settle in, its awesome power....
when it does you'll really appreciate the power these 106's have...My engine took I figure 15 gallons to settle in, its awesome power....
03-07-2006, 10:03 PM
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RE: 3w 106 initial test run and observations cont.
can you tell me if you had trumpets on either of these engines and if there is anyone else out there with 10c please feel free to let me know what you think
03-07-2006, 11:33 PM
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RE: 3w 106 initial test run and observations cont.
I had same problem before, just take crab trumpet away and extend vent tube to fuse then problem disappear. the trumpet inet is too samll not enough air for breathing, hope this help
03-08-2006, 12:09 AM
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RE: 3w 106 initial test run and observations cont.
Don't these airplanes glide ? What would be wrong with testing the carb settings about 3 mistakes high ? If it dies, so what ? We test 45 lb 87 inch wingspan 200 mph race planes and they can be brought in gliding...Most of the time the pilots kill the engine on approach anyway, on purpose....
03-08-2006, 02:01 PM
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RE: 3w 106 initial test run and observations cont.
ORIGINAL: RCIGN1
Don't these airplanes glide ? What would be wrong with testing the carb settings about 3 mistakes high ? If it dies, so what ? We test 45 lb 87 inch wingspan 200 mph race planes and they can be brought in gliding...Most of the time the pilots kill the engine on approach anyway, on purpose....
Don't these airplanes glide ? What would be wrong with testing the carb settings about 3 mistakes high ? If it dies, so what ? We test 45 lb 87 inch wingspan 200 mph race planes and they can be brought in gliding...Most of the time the pilots kill the engine on approach anyway, on purpose....
BINGO.... not sure why we hear so much about dead sticks and crashes on new engines... on engines that are breaking in.. I NEVER get low or very far from the field when I invert, knife, or go from low throttle to WOT on the first few flights ... just in case.. saved at least two planes that way... like you said 2-3 mistakes high works.
I saw a guy fly a brand new Extra with a new (run once on ground that day) DA-100.. it was running rough to begin with.. but he knew everything so I just shut my mouth. He took off at full throttle and inverted his plane literally the second it was 10' off the ground.. (apparently to show off) it went into an immediate dead stick.. plane went down before it cleared the end of the runway.. total loss. Don't get it.
I'll do a ground run to ballpark the needles - then take off at 1/3 throttle, do a nice easy circular climbout while trimming for level flight on the passes parallel to the runway... once up about 200' + I'll cut back to idle and check landing speeds, then roll it over and start playing with transitions.. if it dies there is more than enough air to get home safely. Usually about 2-3 flights and I have everything dialed in perfectly.
DP
03-08-2006, 04:22 PM
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RE: 3w 106 initial test run and observations cont.
Guys, the airplane was being flown very very conservatively..........................my point...............was that the common explanation of these symptoms (ie. an airflow issue around the carb) is perhaps misleading and I believe it to be excess fuel from a rich condition being TRAPPED inside the trumpet because of the trumpet construction causing the temporary flooding under certain manouvers.
Just trying to help someone out
REMEMBER TO LOOK OUT FOR ........"PIMP MY PLANE"
Just trying to help someone out
REMEMBER TO LOOK OUT FOR ........"PIMP MY PLANE"
03-08-2006, 06:33 PM
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RE: 3w 106 initial test run and observations cont.
A reed valve engine does not blow fuel back through the carb unless the reeds are leaky, and if that's the case the engine probably won't run anyway.....
My personal opinion is that the trumpet is just another way for 3W to get money from customers...RTK has it nailed with his little box with a hose in it from the cover...There is no trumpet on a BME 110.....
Walbro and Tillotson carbs are made to work with atmospheric pressure...anything that changes that screws up the carb...Big time...
The trumpet, as designed, would work better if facing forward...The drone engines we use for racing had the carbs facing straight forward, the engines were pushers...Air was ducted directly into the carbs...there was a small tube in the intake venturi that led to the cover over the diaphragm...There were no other holes, so the air over the diaphragm was the same as the air coming into the carbs...NO problems....
My personal opinion is that the trumpet is just another way for 3W to get money from customers...RTK has it nailed with his little box with a hose in it from the cover...There is no trumpet on a BME 110.....
Walbro and Tillotson carbs are made to work with atmospheric pressure...anything that changes that screws up the carb...Big time...
The trumpet, as designed, would work better if facing forward...The drone engines we use for racing had the carbs facing straight forward, the engines were pushers...Air was ducted directly into the carbs...there was a small tube in the intake venturi that led to the cover over the diaphragm...There were no other holes, so the air over the diaphragm was the same as the air coming into the carbs...NO problems....
03-08-2006, 06:39 PM
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RE: 3w 106 initial test run and observations cont.
Okay Ian, I'll bite........ "Pimp My Plane"?
Anyhoo, glad you got the plane up last weekend. I've had engines with no trumpets behave in a similar manner. Do a slow roll and when it gets to right knife edge, it runs richer and burbles. Runs clean at all other attitudes. Tried all the usual stuff, (cover over the diaphragm holes, tube to inside the fuse, fooling with the needles, flying while standing on one foot, etc.) with limited success. Pull hair out, didn't help. Certainly makes rollers interesting. I'm thinking airflow inside the cowl is different in right knife, and that affects things. I might remove the cowl and see if it still happens.
Tim
Anyhoo, glad you got the plane up last weekend. I've had engines with no trumpets behave in a similar manner. Do a slow roll and when it gets to right knife edge, it runs richer and burbles. Runs clean at all other attitudes. Tried all the usual stuff, (cover over the diaphragm holes, tube to inside the fuse, fooling with the needles, flying while standing on one foot, etc.) with limited success. Pull hair out, didn't help. Certainly makes rollers interesting. I'm thinking airflow inside the cowl is different in right knife, and that affects things. I might remove the cowl and see if it still happens.
Tim
03-19-2006, 11:49 AM
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RE: 3w 106 initial test run and observations cont.
3w RUNNING BAD WHEN ROLLING AND K.E SOLUTION
tried tweaking the needles this way and that.............NO DRAMATIC CHANGE EITHER WAY
tried running the carb diaphram air line back into the fuz................NO CHANGE WHATSOEVER
took the snorkel/trumpet off the carb .......retuned like I would with any other engine..............
RUNS PERFECT IN EVERY ATTITUDE WITH MORE POWER THAN IT EVER HAS.
Perofrmance is slightly more than my DA100 which has around 20 gallons thru it and this was the 3w on gallon 2.
JUST POSTING WHAT WE HAVE FOUND IN THE HOPE IT MIGHT HELP SOMEONE ELSE WHO IS HAVING GRIEF
kindest regards, IanB
tried tweaking the needles this way and that.............NO DRAMATIC CHANGE EITHER WAY
tried running the carb diaphram air line back into the fuz................NO CHANGE WHATSOEVER
took the snorkel/trumpet off the carb .......retuned like I would with any other engine..............
RUNS PERFECT IN EVERY ATTITUDE WITH MORE POWER THAN IT EVER HAS.
Perofrmance is slightly more than my DA100 which has around 20 gallons thru it and this was the 3w on gallon 2.
JUST POSTING WHAT WE HAVE FOUND IN THE HOPE IT MIGHT HELP SOMEONE ELSE WHO IS HAVING GRIEF
kindest regards, IanB
03-19-2006, 12:43 PM
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RE: 3w 106 initial test run and observations cont.
ORIGINAL: IanB
3w RUNNING BAD WHEN ROLLING AND K.E SOLUTION
tried tweaking the needles this way and that.............NO DRAMATIC CHANGE EITHER WAY
tried running the carb diaphram air line back into the fuz................NO CHANGE WHATSOEVER
took the snorkel/trumpet off the carb .......retuned like I would with any other engine..............
RUNS PERFECT IN EVERY ATTITUDE WITH MORE POWER THAN IT EVER HAS.
Perofrmance is slightly more than my DA100 which has around 20 gallons thru it and this was the 3w on gallon 2.
JUST POSTING WHAT WE HAVE FOUND IN THE HOPE IT MIGHT HELP SOMEONE ELSE WHO IS HAVING GRIEF
kindest regards, IanB
3w RUNNING BAD WHEN ROLLING AND K.E SOLUTION
tried tweaking the needles this way and that.............NO DRAMATIC CHANGE EITHER WAY
tried running the carb diaphram air line back into the fuz................NO CHANGE WHATSOEVER
took the snorkel/trumpet off the carb .......retuned like I would with any other engine..............
RUNS PERFECT IN EVERY ATTITUDE WITH MORE POWER THAN IT EVER HAS.
Perofrmance is slightly more than my DA100 which has around 20 gallons thru it and this was the 3w on gallon 2.
JUST POSTING WHAT WE HAVE FOUND IN THE HOPE IT MIGHT HELP SOMEONE ELSE WHO IS HAVING GRIEF
kindest regards, IanB
03-26-2006, 06:22 PM
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RE: 3w 106 initial test run and observations cont.
update on engine
2 and a bit flying gallons now without the trumpet turns the msc 26x10 at 6840rpm.
Have to say removing the trumpet has transformed this motor.
Amazing performance
2 and a bit flying gallons now without the trumpet turns the msc 26x10 at 6840rpm.
Have to say removing the trumpet has transformed this motor.
Amazing performance
