Strange DA100 issues
05-04-2003, 07:43 PM
#1
Senior Member
Thread Starter
My Feedback: (3)
Join Date: Jan 2002
Location: Elk Rapids, MI
Posts: 103
Likes: 0
Received 0 Likes
on
0 Posts
Strange DA100 issues
I had the first flight on my DA100 powered Velox this weekend. Everything was great except that when I roll the airplane at anything less than full throttle the engine sounds like it's going to die as it gets inverted. It's a very strange sound, almost like the prop is suddenly loading the engine tremendously, then as you come around to upright, the R's start coming back up. I'm not sure I want to try inverted flight with it yet! It also hesitates a little from idle to full. What do you guys think?
You can see the first flight and hear the problem (if you listen REALLY closely) at:
http://www.plane-crazy.com/images/veloxfirst.wmv (6 megs)
http://www.plane-crazy.com/images/firstvelox.wmv (18 megs)
-Aaron
You can see the first flight and hear the problem (if you listen REALLY closely) at:
http://www.plane-crazy.com/images/veloxfirst.wmv (6 megs)
http://www.plane-crazy.com/images/firstvelox.wmv (18 megs)
-Aaron
05-07-2003, 01:00 AM
#3
My Feedback: (3)
Join Date: Mar 2003
Location: Spring,
TX
Posts: 543
Likes: 0
Received 0 Likes
on
0 Posts
Strange DA100 issues
I also think it is your low end that is rich.
I ended up almost turning my low end a full turn in before I was happy with it and richened my high end by 1/3 turn.
Runs great now but my 2nd through 6th flight was a deadstick. Everytime I did a snap it would die b/c it was too rich.
Haven't had a deadstick from flight 7 - 67 though
That should get you having some fun with it.
I ended up almost turning my low end a full turn in before I was happy with it and richened my high end by 1/3 turn.
Runs great now but my 2nd through 6th flight was a deadstick. Everytime I did a snap it would die b/c it was too rich.
Haven't had a deadstick from flight 7 - 67 though
That should get you having some fun with it.
05-07-2003, 01:22 AM
#4
Senior Member
Thread Starter
My Feedback: (3)
Join Date: Jan 2002
Location: Elk Rapids, MI
Posts: 103
Likes: 0
Received 0 Likes
on
0 Posts
Strange DA100 issues
Can someone explain to me why to rich of a needle setting would cause power fluctuations during manuvers? I definately agree with you guys that it's rich, I just don't understand why with a pumped carb it would flux like that. It's always something..... <VBG>
-Aaron
-Aaron
05-07-2003, 02:51 AM
#5
My Feedback: (3)
Join Date: Mar 2003
Location: Spring,
TX
Posts: 543
Likes: 0
Received 0 Likes
on
0 Posts
Strange DA100 issues
My theory was that when I snapped the plane there wasn't as much air in the cowl (kinda like a vaccum) and with it allready being too rich plus loosing the little bit of air it has, will flood and kill it.
After I leaned it, it didn't do it anymore. After about 20 flights I did some extensive baffling to the cowl with the hope of getting as much air over the heads as possible and to keep the turbulance to a minimum where the carb is located to help prolong the engine life as long as possible. (Don't know that it did any good b/c it flew fine before, but at least it doesn't fly any worse)
After I leaned it, it didn't do it anymore. After about 20 flights I did some extensive baffling to the cowl with the hope of getting as much air over the heads as possible and to keep the turbulance to a minimum where the carb is located to help prolong the engine life as long as possible. (Don't know that it did any good b/c it flew fine before, but at least it doesn't fly any worse
)
05-07-2003, 03:03 AM
#6
My Feedback: (31)
Strange DA100 issues
I beleive a good explantion is below, can't take credit for the information. I copied it from another thread. ( Tim)
If the engine is running rich when upright and level, the excess fuel will pool in the bottom of the reed cage. If you roll inverted, this fuel will get dumped onto the spinning crank and get whipped into the transfer ports, making the engine burble very rich. A intake horn helps to ensure that the mixture is correct over the entire throttle range so fuel won't puddle.
Tim) If the engine is running rich when upright and level, the excess fuel will pool in the bottom of the reed cage. If you roll inverted, this fuel will get dumped onto the spinning crank and get whipped into the transfer ports, making the engine burble very rich. A intake horn helps to ensure that the mixture is correct over the entire throttle range so fuel won't puddle.
