Webra 1.45 problem

[Gordon Anderson]

Keith,
 
Thanks a lot for this advice. It give me a lot to work with, I appreciate the
detail.
I did have a typo on the prop, should have said 17x12.
 
--Gordon

  _____  

From: discussion-request at nsrca.org [mailto:discussion-request at nsrca.org] On
Behalf Of Keith Black
Sent: Saturday, July 24, 2004 9:19 PM
To: discussion at nsrca.org
Subject: Re: Webra 1.45 problem


First thing I would do is to get a higher pitched prop, I don't think the 17x2
has quite enough bite ;-)
 
Seriously though, have you ever adjusted the pump pressure? I've now had four
different Webra or Bully 1.45 engines and all have had to have the pump pressure
reduced (turning the pump screw counter-clockwise) to varying degrees to run
properly.
 
Questions:
Does the engine have trouble idling at 1900-2000 rpm? 
Does it profuesly spit fuel out the carb and pipe? 
Is it blowing a LOT of smoke when it runs?
When it dies does it cough a time or two and blow out a few puffs of smoke?
 
If the answer to three or more of these is yes then I would try the following:
 
(NOTE: The following assumes you have already bench run the engine through at
least 1/2 gallon starting extremely rich then varying the needle settings and
throttle speeds.)
 
1. Reduce the pump pressure 1/2 to 3/4 turn from the factory setting.
2. Use an OS Type-F plug.
3. Run a 17x10N prop (at least until the engine is broken in well, that's what I
always use).
4. Adjust the low end needle so it will idle at around 2K for about 30 seconds
then accelerate to full throttle without coughing on the run up. 
5. Adjust the high end idle so it will spin up around 8300 rpm (with the 17x10
and greves pipe set per Piedmonts specs) but is still blowing a good amount of
smoke. I make sure mine always blows smoke even after break-in, but even more so
during the first several gallons of fuel.
 
When the high end is pretty rich, as you want it for flight break-in, you may
find it has trouble going from the mid-range to high throttle without coughing,
sputtering and sometimes even dying. Two of my engines have had this problem,
two haven't. It's possible that the two that had this problem were left richer
during the break-in flights. The two that had this trouble would go from idle to
full throttle just fine but would have trouble if run at mid range for a while
then pushed to full throttle. I believe this was because I had them so rich, but
my goal was to break them in without damaging the engine. If you have this
trouble then for your first gallon of flight break-in just avoid the mid-range
and fly primarily at idle and full throttle. That may sound screwy but it worked
for me. After you've got a couple of gallons of fuel through start slowly
leaning out the high end needle so the mid-range transition improves. As the
engine breaks in and you get closer to the proper high end setting the mid-range
will improve and eventually should be very smooth and reliable. Note, as you
adjust the high end you should also re-adjust the low end as described in step
#4 above.
 
Expect the bearings to need replacing by flight 40 or perhaps even earlier. On
my most recent engine by the time I got it broken in really well I only had
about 15 or so flights until I needed to change the bearings. However, after the
bearing change it ran better than ever being broken in and having new bearings .
 
Best of luck,
Keith Black
 
 

----- Original Message ----- 
From: Gordon Anderson <mailto:GAA at owt.com>  
To: discussion at nsrca.org 
Sent: Saturday, July 24, 2004 3:37 PM
Subject: Webra 1.45 problem



I'm having a problem with my Webra 1.45 and I hope someone can help me out. I
have a new Hydeout (thanks to the guys that gave me the control throw advice!)
with a new Webra 1.45. Below are the details on the motor setup:

Prop: APC 17x2 
Fuel: Magnum #1 
Plug: OS #8 
Pipe: Greves 
Mount: Hyde type soft mount and nose ring 
Tank: Tetra 20oz, on CG of model 
I have about 2/3 of a gallon of fuel run through the motor, this Webra uses the
regular carb with the high speed and low speed needles.

The problem is the motor dies when I roll from inverted to upright. This happens
mostly after I have been at idle for a while. I'm flying the advanced routine
and it dies during the roll out on the bunt and the bottom of the double I even
the slow roll. I have never made it more than about 3 minutes into a flight.

It seems to run fine on the down lines at idle, like in the stall turns and the
outside square loop. 
When it dies it sounds like someone pulled the fuel line off the engine, it just
un winds. We tried leaning the low speed needle, replaced the tank internal fuel
line to the clunk.

Any advice? 

--Gordon 

-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://lists.f3a.us/pipermail/nsrca-discussion/attachments/20040724/f26402ab/attachment.html