Webra 145 pump pressure ?

Lance Van Nostrand patterndude at comcast.net
Mon Apr 4 19:56:07 AKDT 2005


Paul,
I've found the Webra loves nitro more than other 2 strokes. Why not up the 
nitro to at least 15 or probably 20.  Not sure what fuel you are using that 
is 50-50 castor syn.  The omega 11-11 is a rarity.  If you've got it running 
that well on your weird soup you are doing pretty well.
--Lance

----- Original Message ----- 
From: "Paul Horan" <phoran at vvm.com>
To: <discussion at nsrca.org>
Sent: Monday, April 04, 2005 1:56 AM
Subject: Re: Webra 145 pump pressure ?


> Steve,
>    The 20 and 5% I am refering to is nitro.  I mixed 2 gallons one 5% 
> nitro with castor/synthetic oil and one 15% nitro with all synthetic oil 
> to get 10 % nitro with the oil being composed of 2/3 synthetic and 1/3 
> castor.  I want the castor to guard against wear during break-in.  I am 
> new to tuned pipes, the pipe is long to keep the rpm down during break-in.
>    If I understand you correctly, when I shorten the pipe it will richen 
> the mid-range.  Is this correct ?   Currently I am delibrately rich at the 
> top end and the mid-range is only slightly rich (pinch test).
>    I am reluctant to mess with the pump and hoping that as I get more fuel 
> through the engine the mid-range will richen up.  Is that reasonable ?
>
> Thanks,
> Paul
>
> ----- Original Message ----- 
> From: "RC Steve Sterling" <rcsteve at tcrcm.org>
> To: <discussion at nsrca.org>
> Sent: Sunday, April 03, 2005 5:13 PM
> Subject: RE: Webra 145 pump pressure ?
>
>
>> If I am reading your message correct, you are running 25% total oil (20%
>> synthenic and 5% castor)??
>>
>> If so, that is probably too much oil for the Webra. I once tried 20% 
>> total
>> oil, and it didn't like it much. I backed down to 17-18% total oil and it
>> ran much better. I happen to run all synthetic now, but have tried some 
>> with
>> a little castor (total oil 18%) and it ran fine on that also.
>>
>> 7300 RPM is pretty low on a 16.5 x 12 prop for this engine. I think most 
>> get
>> more like 7900 RPM. You may need to adjust pipe length a little. If it is
>> anything like my Greve pipe, it really makes a big difference on the
>> midrange mixture as well. My troubles were with too rich midrange. I'd 
>> try
>> different fuel, then try a 1/2 inch pipelength change first before trying
>> pump pressure.
>>
>> -----Original Message-----
>> From: discussion-request at nsrca.org
>> [mailto:discussion-request at nsrca.org]On Behalf Of Paul Horan
>> Sent: Sunday, April 03, 2005 10:09 AM
>> To: discussion at nsrca.org
>> Subject: Webra 145 pump pressure ?
>>
>>
>>    My Webra has a good top and bottom end. Only about a gallon and a half
>> through it so far.
>> The top end is nice and smokey, idle is solid, but the mid range is very
>> little smoke.
>> It is on a Prophecy running a 16.5 x 12 at 7300 rpm with the Macs pipe at 
>> 27
>> inches.
>> Most of my flight is at roughly 1/2 throttle.  When I land the oil 
>> residue
>> on the coupler and
>> fuselage is medium brown - fuel is a mix of 20 % synthetic and 5 % castor
>> synthetic.
>> Main needle is open 1.5 turns.
>>    I am wondering if I should increase the pump pressure to richen up the
>> midrange.
>> Or am I just being too fussy ?
>> Thanks,
>> Paul Horan
>> KC5NF
>> AMA 57131
>> NSRCA 3606
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