Webra 145 pump pressure ?
Lance Van Nostrand
patterndude at comcast.net
Wed Apr 6 19:01:30 AKDT 2005
Paul,
The prop you have is not, in my opinion, a light load. The 145 is a bored
out 120 long stroke, which has made it closer to an over square design. I
had some conversations about this with Lynn Osborn back when he was
servicing the engines and he told me to prop it to get the rpms close to
8000 and the engine will be much happier. I went with the 17x10 and was
quite happy.
Your setup really looks pretty good and it proves that one can find a
sweet spot at different places - there is no one right way to do this. I
would anticipate that as the weather heats up you'll want the full 15% or
maybe 20.
I can understand your concern about break in and using castor. However,
I'll just pass on that when I was buying and running these engines the
factory advice was all synthetic. I never used castor and didn't see that
it caused any problems. Now that I'm servicing Mintors and have a close
relationship with the factory we've had a lot of discussions on oils, fuels
and such. Castor has some known properties to lacquer parts. This is bad
for our engines for several reasons. But this happens after extended use.
You might want to consider weaning from it when you think its broken in -
assuming you feel strongly about keeping it now. PowerMaster has a higher %
of their castor/syn blend as castor than, say, Magnum. The slight brown
residue is therefore nothing to be concerned with because the extra castor
can come out brown even when the engine is properly tuned. There's really
no harm in backing out the pump screw 1/8 turn to see if its a bit better.
Down in your area of Texas (mine too) there is a Ritches Brew and they have
fuels with different % of the oil being castor. I actually found their
synthetic pylon blend worked well in my Webras, but I've tried it in the
Mintors and it works OK but not as well as Powermaster or Magnum or some
other fuels.
Yes, I'll be at Waco. Looking forward to the judging recertification
Saturday night. Should give you and I a few more interesting scenarios to
discuss. I'll have my protoge' (a newbie) and my friend Terry Brox has been
in Austin and will be there too. I think the whole Dallas gang will be
there, except for one dimwit that got the date screwed up with a soccer
tourney. Wish your contest were at the beginning of May.......
--Lance
----- Original Message -----
From: "Paul Horan" <phoran at vvm.com>
To: <discussion at nsrca.org>
Sent: Tuesday, April 05, 2005 12:06 AM
Subject: Re: Webra 145 pump pressure ?
> Lance,
> The engine is running well at idle and WOT, mid range is only slightly
> rich and may be cooking the oil some. I get a brownish exhaust oil with a
> slightly cooked smell.
> I am running PowerMaster mix of one gallon 15 % nitro with synthetic
> oil and one gallon of 5% nitro with castor/synthetic oil. I'm concerned
> about keeping the engine well lubed during break-in. Vertical is almost
> unlimited with a 16.5 x 12 prop @ 7300 rpm. This prop/rpm is a very light
> load for this engine. Exhaust oil at WOT is clear with no cooked smell,
> but since most of my flight is below 2/3 throttle the mid-range may be a
> bit lean (brownish exhaust oil) or maybe I'm just too fussy.
> What do you think ?
> Will you be at Waco, Bobby, BW, myself and possibly a couple of others
> from Temple will be there.
> See you,
> Paul
> ----- Original Message -----
> From: "Lance Van Nostrand" <patterndude at comcast.net>
> To: <discussion at nsrca.org>
> Sent: Monday, April 04, 2005 10:56 PM
> Subject: Re: Webra 145 pump pressure ?
>
>
>> 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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>>>
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