X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from mail-pb0-f52.google.com ([209.85.160.52] verified) by logan.com (CommuniGate Pro SMTP 5.4.5) with ESMTPS id 5513598 for flyrotary@lancaironline.net; Sat, 28 Apr 2012 14:27:05 -0400 Received-SPF: pass receiver=logan.com; client-ip=209.85.160.52; envelope-from=rwstracy@gmail.com Received: by pbbro8 with SMTP id ro8so704402pbb.25 for ; Sat, 28 Apr 2012 11:26:28 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=subject:references:from:content-type:x-mailer:in-reply-to :message-id:date:to:content-transfer-encoding:mime-version; bh=8fWzNRbP7gi33i8EvO/IYdkedVQuHG7gdYmLBh/qrUw=; b=q7ESfjPCk4MTWV43Kj4kg4OKXx2jd3X6E/HC8sYbEpNMjoD7cjTSTfhbGJFrpaP2/c jlNM/3TriEmySYB1GfB7pMNPDoZAZHgFFdpr7VxpAVAa4XimdtMBJlTfH1e2jZQKcfsI x5rWszeOwtbb23PUx3lKzPaV6mLNEKFTIG/0aDtFGMtS7S8tJdDvsWRdQqoeKGa/I6AF gYbCqg3XqYSU+hdmdxiXlECQdnXroG0morHt+24ZG61B1gLQss9av12jXTXPvV4pUqVa LJm87Ccz33qyricN1761LuCOqGL1gEUvqqHe1wcKvpnZWt7mcidobzsPe9ZfkNYVO9Dq fKOQ== Received: by 10.68.242.105 with SMTP id wp9mr6190865pbc.40.1335637588433; Sat, 28 Apr 2012 11:26:28 -0700 (PDT) Return-Path: Received: from [192.168.1.2] (237.sub-166-250-161.myvzw.com. [166.250.161.237]) by mx.google.com with ESMTPS id xd9sm6437347pbc.38.2012.04.28.11.26.24 (version=TLSv1/SSLv3 cipher=OTHER); Sat, 28 Apr 2012 11:26:26 -0700 (PDT) Subject: Re: [FlyRotary] Re: Hiccup References: From: Tracy Content-Type: multipart/alternative; boundary=Apple-Mail-7-848099381 X-Mailer: iPad Mail (8F191) In-Reply-To: Message-Id: <2320EDFD-0051-45F3-A2EA-D1102AD81A93@gmail.com> Date: Sat, 28 Apr 2012 12:26:21 -0600 To: Rotary motors in aircraft Content-Transfer-Encoding: 7bit Mime-Version: 1.0 (iPad Mail 8F191) --Apple-Mail-7-848099381 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=utf-8 The only thing I can think of that would match that symptom is an intermitte= nt open in one of the crank sensor connections. If it happened only at high throttle, that would match the symptom I had way= back when I had a failure of the welds that fixed the sun gear to the input= shaft. I assume your drive is either a later model after I went to the pin= ned input shaft or it has been retrofitted with a pin. In this case, The s= ymptom FEELS exactly like an engine miss or backfire but is really a momenta= ry slipping of the input shaft before it temporarily friction welds itself b= ack to the sun gear. This happens at high power setting, not at low throttl= e in a descent though so I don't think that's what's happening here unless y= ou have two unrelated problems. An engine miss during descent can be caused by the engine running at a very l= ow MP (due to windmilling prop) where there is not enough combustion chamber= pressure to give reliable combustion. Cars avoid this (in a downhill coas= ting situation) by cutting the fuel injection completely. I chose not to do= this on the EC2/3 because we depend on a little fuel-oil injection to lubri= cate the apex seals. What many builders perceive as a MISS is often an occa= sional FIRE when there happens to be enough fuel and MP to combust. This is only general info so don't take it as the gospel on what your engine= is doing. I'm a long way from your engine and going on very little info. =20= Tracy Sent from my iPad On Apr 28, 2012, at 6:34 AM, "Bill Bradburry" wro= te: > The hiccup is like a backfire. It really shakes the engine. You can feel= it thru the airframe. But it is quick, like it was a single event. BUP! Th= en it is smooth again for a minute or two. Much closer together if you are i= n a powered decent. > =20 > Bill > =20 > From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On Be= half Of Tracy > Sent: Friday, April 27, 2012 5:36 PM > To: Rotary motors in aircraft > Subject: [FlyRotary] Re: Hiccup > =20 > Don't know about the hiccup but you can easily calibrate the airspeed. Go= to calibration screen for TAS, adjust the sensor offset parameter to one le= ss than the current ADC reading. Do this at zero airspeed of course. >=20 > Tracy > Sent from my iPad >=20 > On Apr 27, 2012, at 2:58 PM, "Bill Bradburry" w= rote: >=20 >> I am experiencing an occasional hiccup while in cruise and more often dur= ing a decent under power. I am pretty certain that I saw a comment on this p= reviously from Tracy but I have not been able to find it. Can someone set m= e straight on what to do about this? >> =20 >> My mixture graph is not working and I will be sending the EM-2 to Tracy a= s soon as he returns from Colorado. I also show a true airpspeed of 22 mph i= n the hangar and it seems to be about that much or a little more in error in= cruise. I don=E2=80=99t think I can calibrate this item? >> =20 >> Bill B >=20 --Apple-Mail-7-848099381 Content-Transfer-Encoding: quoted-printable Content-Type: text/html; charset=utf-8
The only thing I can think of that woul= d match that symptom is an intermittent open in one of the crank sensor conn= ections.

If it happened only at high throttle, that= would match the symptom I had way back when I had a failure of the welds th= at fixed the sun gear to the input shaft.  I assume your drive is eithe= r a later model after I went to the pinned input shaft or it has been retrof= itted with a pin.   In this case, The symptom FEELS exactly like an eng= ine miss or backfire but is really a momentary slipping of the input shaft b= efore it temporarily friction welds itself back to the sun gear.  This h= appens at high power setting, not at low throttle in a descent though so I d= on't think that's what's happening here unless you have two unrelated proble= ms.

An engine miss during descent can be caused by t= he engine running at a very low MP (due to windmilling prop) where there is n= ot enough combustion chamber pressure to give reliable combustion.   Ca= rs avoid this (in a downhill coasting situation) by cutting the fuel injecti= on completely.  I chose not to do this on the EC2/3 because we depend o= n a little fuel-oil injection to lubricate the apex seals.  What many b= uilders perceive as a MISS is often an occasional FIRE when there happens to= be enough fuel and MP to combust.

This is only gen= eral info so don't take it as the gospel on what your engine is doing.  = ;I'm a long way from your engine and going on very little info.  
=

Tracy

Sent from my iPad

On Apr 28, 2= 012, at 6:34 AM, "Bill Bradburry" <bbradburry@bellsouth.net> wrote:

The hiccup is like a backfire.  It= really shakes the engine.  You can feel it thru the airframe.  But it is q= uick, like it was a single event. BUP! Then it is smooth again for a minute or two.&nbs= p; Much closer together if you are in a powered decent.

 

Bill

 

From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of Tracy
Sent: Friday, April 27, 2012 5= :36 PM
To: Rotary motors in aircraft
Subject: [FlyRotary] Re: Hicc= up

 

Don't know about the hiccup but you can easily calibrate the airspeed.  Go to calibration screen for TAS, adjust the sensor offset parameter to one less than the curr= ent ADC reading.  Do this at zero airspeed of course.

Tracy
Sent from my iPad


On Apr 27, 2012, at 2:58 PM, "Bill Bradburry" <bbradburry@bel= lsouth.net> wrote:

I am experiencing an occasional hiccup while in cruise and= more often during a decent under power.  I am pretty certain that I saw= a comment on this previously from Tracy= but I have not been able to find it.  Can someone set me straight on wh= at to do about this?

 <= /o:p>

My mixture graph is not working and I w= ill be sending the EM-2 to Tracy as soon as he returns from <= st1:state w:st=3D"on">Colorado.  I also show a true airpspeed of 22 mph in the hangar and it seems to be abou= t that much or a little more in error in cruise.  I don=E2=80=99t think I= can calibrate this item?

 <= /o:p>

Bill B<= /o:p>

= --Apple-Mail-7-848099381--