[NSRCA-discussion] [SA] RE: Thoughts about lack of power of my DA150??

Tue Feb 7 12:11:22 AKST 2006

Don,

Sticking plunger, spring..
You mean underneath diaphragm? I have removed diaphragm to solder a tube on
the vent hole. But after installing all back, I didn't notice any
difference. Not sure I understand

Patrick

-----Oorspronkelijk bericht-----
Van: mini-iac at yahoogroups.com [mailto:mini-iac at yahoogroups.com] Namens
flyinghamiltons at adelphia.net
Verzonden: dinsdag 7 februari 2006 19:21
Aan: PPandelaers
CC: Discussion at Nsrca.Org; Mini IAC (Mini IAC); 'JShulman'
Onderwerp: Re: [SA] RE: Thoughts about lack of power of my DA150??

Pop-off pressures, at the plunger/spring/or  stinking could cause this...
don
---- PPandelaers <ppandelaers at pandora.be> wrote: 
> Hi Jason,
> 
>  
> 
> The plane I', flying is an Extra 330S from PL_Prod (now PLF). I did do
front
> baffling, closed the cowl hole in front f the carb. So most of the air for
> the carb is the cooling air of the engine
> 
>  
> 
> Everybody seems to agree that the RPM's are about right. My altitude is
> about sea level. Nevertheless, my competition friends "claim": they are
> running 5800, this was my reference.
> 
>  
> 
> The headers I'm using have a length of 310mm, so it seems that I indeed
> could shorten some and see if it helps. DA has responded, I'm waiting for
> the port timing, so I can rationalize the need for shortening the headers.
> DA is shipping it's standard headers at  305mm.
> 
>  
> 
> I have made sure to avoid a blast in the carb vent hole for sure.
> 
>  
> 
> I have always been very sensitive when turning in the needles, so I don't
> think I have damaged anything.
> 
>  
> 
> Still, with the recommended needle setting I have very poor throttle
> response in the air, just far too rich in low to middle, not achieving
full
> power at full. I was thinking my header length had something to do with
it.
> But now I see, I'm at the standard length of DA_headers. So what else
could
> be wrong?
> 
>  
> 
> BTW: 
> 
> *	What prop are you running, what RPM"s??
> *	Total distance to the rear muffler plate?  In my case the MTW
> TD110k's add 310 mm to the headers.
> 
>  
> 
> Thanks!!
> 
>  
> 
> Patrick
> 
>  
> 
>  
> 
>  
> 
> -----Oorspronkelijk bericht-----
> Van: JShulman [mailto:jshulman at cfl.rr.com] 
> Verzonden: maandag 6 februari 2006 23:44
> Aan: ppandelaers at pandora.be
> Onderwerp: Thoughts about lack of power of my DA150??
> 
>  
> 
> Patrick,
> 
>  
> 
> What airplane is this in? What does the cowling look like? Baffles? Carb
> area? 5600 on a Mej 32x10 sounds about right. One thing you should do is
> have the low at no less than 1/2, and the high not less than 2 turns. And
> when you turn the needles all the way in, do you make sure they're closed?
> If so, you can distort the carb needle seating in the carb making it more
> difficult to set the needles correctly. When you close the needles, make
> sure you do not do it hard. The only thing with the carb tube I've found
is
> it makes the motor run leaner. I just make sure not to blast the carb hole
> in front. I just make a cover so it can't get direct air through the hole.
> My headers are 265mm long and it seems to work well.
> 
>  
> 
> Hope this helps.
> 
>  
> 
> Regards,
> Jason
> www.jasonshulman.com
> www.shulmanaviation.com
> www.composite-arf.com 
> 
> -----Original Message-----
> From: nsrca-discussion-bounces at lists.nsrca.org
> [mailto:nsrca-discussion-bounces at lists.nsrca.org]On Behalf Of PPandelaers
> Sent: Monday, February 06, 2006 5:27 PM
> To: Discussion at Nsrca.Org; Mini IAC (Mini IAC)
> Subject: [NSRCA-discussion] Thoughts about lack of power of my DA150??
> 
> Hi guys,
> 
>  
> 
> I'm wondering if you have opinions on my below assumptions. It's a mail I
> have sent to DA, but no answer as of yet. 
> 
>  
> 
> Could I be right, should I rather lengthen or shorten my exhaust system?
> 
>  
> 
> Thanks
> 
>  
> 
> Patrick
> 
>  
> 
>  
> 
>  ============================================================
> 
> I'm running a DA150 on MTW, short cans TD75K, Mejzlik 28.5x12
> 
>  
> 
>  
> 
> Started running-in the engine a couple of months ago. >From day 1, I got
> 5600 RPM.
> 
> Now, 50 liter gas down, no change at all in RPM :-(  I get exactly the
same
> RPM on a 32x10 2-blade.
> 
> I'm experiencing great difficulty in adjusting the engine. I don't seem to
> be able to get full power, particularly not in the air. I get the feeling
I
> don't even get the 5600 in the air.
> 
> Tried about anything you can imagine, with adjusting needles, soldering a
> little tune on the diaphragm cap, measuring pressure where it should be
> done.
> 
>  
> 
>  
> 
> Let's forget about air behaviour, I would expect significantly higher RPM,
> even on the ground. Motor is not sagging when I keep it running full
> throttle, I baffled the engine, cooling is adequate.
> 
>  
> 
> Here's what I think is going wrong, I would really like to get your
opinion
> on it.
> 
> At 5600 RPM, I think I get some refection of the exhaust system exactly
> during the intake timing.  If this is so, I just can't get enough mixture
> inside the cylinder. 
> 
> At low RPM, it's always running rich, if I want to improve that, I have to
> tweak the "L" as low a 3/8 (instead of the 5/8) . The high needle is not
> sensitive at all, it's like it doesn't matter where you put it. With the
> low, at 3/8, starting a cold engine takes several restarts.
> 
>  
> 
> The distance of piston to the first wall in exhaust systems is about 630mm
> 
>  
> 
> *        Could I be right? 
> 
> *        How much would I have to lengthen or shorten the exhaust tubing? 
> 
> *        Secondary questions: 
> 
> o       How many degrees is the intake open, 
> 
> o       When does the intake open: How many degrees from exhaust opening
> (piston moving down) till intake port opens? 
> 
> *        What RPM should I expect on the Mejzlik 28.5x12. 
> 
>  
> 
>  
> 
>  
> 
> Your advise would be highly appreciated!!!
> 
>  
> 
> Patrick
> 
>  
> 
>  
> 
>  
> 
>  
> 
> 
> 
> [Non-text portions of this message have been removed]
> 
> 
> 
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