X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from willowsprings.uwyo.edu ([129.72.10.31] verified) by logan.com (CommuniGate Pro SMTP 6.0c2) with ESMTPS id 5868756 for flyrotary@lancaironline.net; Thu, 08 Nov 2012 10:53:00 -0500 Received-SPF: none receiver=logan.com; client-ip=129.72.10.31; envelope-from=SBoese@uwyo.edu Received: from ponyexpress-ht4.uwyo.edu (extlb.uwyo.edu [172.26.4.4]) by willowsprings.uwyo.edu (8.14.4/8.14.4) with ESMTP id qA8FqOZB027616 (version=TLSv1/SSLv3 cipher=AES128-SHA bits=128 verify=FAIL) for ; Thu, 8 Nov 2012 08:52:24 -0700 (MST) (envelope-from SBoese@uwyo.edu) Received: from ponyexpress-m10.uwyo.edu ([fe80::60dd:cb9e:6f71:3d48]) by ponyexpress-ht4.uwyo.edu ([fe80::8de7:b225:a85b:d0ee%13]) with mapi id 14.02.0318.001; Thu, 8 Nov 2012 08:52:24 -0700 From: "Steven W. Boese" To: Rotary motors in aircraft Subject: RE: [FlyRotary] Re: Renesis CAS & EC-2 upgrade? Thread-Topic: [FlyRotary] Re: Renesis CAS & EC-2 upgrade? Thread-Index: AQHNvbaBpgB8aPB3bk6DrrekeHnR8pfgFHXb Date: Thu, 8 Nov 2012 15:52:23 +0000 Message-ID: <3E8191F276108F4481AB0721BBA9269E05DEF5BE@ponyexpress-m10.uwyo.edu> References: In-Reply-To: Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-originating-ip: [75.196.131.170] Content-Type: multipart/alternative; boundary="_000_3E8191F276108F4481AB0721BBA9269E05DEF5BEponyexpressm10u_" MIME-Version: 1.0 --_000_3E8191F276108F4481AB0721BBA9269E05DEF5BEponyexpressm10u_ Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Ed, I tested the engine on the stand with variable resistors across each CAS ye= sterday. With the engine idling at about 1500 RPM, less than 100 ohms resis= tance across either CAS would cause the engine to quit completely. Resistan= ces this low must decrease the voltage generated by the CAS to a value too = low for the controller to use. The engine would not start with 200 ohm acro= ss one CAS and 1K ohm across the other. It didn't matter which CAS had the = lower resistance. The engine would start with 300 ohm across one CAS and 1K= ohm across the other. This makes sense since the CAS cannot generate a ver= y strong signal at cranking speed. What doesn't make sense to me: Starting with 1K resistance across each CAS, if the resistance on one CAS w= as increased to 69K, the engine would still run fine at 1500 RPM. If the re= sistance was increased to 69K on the other CAS, the engine would only run o= n one rotor. It didn't matter which CAS resistance was increased first. With 1K resistance across one CAS, changing the resistance of the other CAS= from 69K back to 1K by connecting a wire would sometimes cause the engine = would miss what seemed to be one firing event. Again, there was no differen= ce in the behavior of either CAS in this regard. The conclusion seems to be that adding the 1K resistor to each CAS seems to= be beneficial and the value of 1K is not critical or on the threshold of c= ausing other problems. Steve ________________________________ From: Rotary motors in aircraft [flyrotary@lancaironline.net] on behalf of = Ed Anderson [eanderson@carolina.rr.com] Sent: Thursday, November 08, 2012 6:38 AM To: Rotary motors in aircraft Subject: [FlyRotary] Re: Renesis CAS & EC-2 upgrade? Likewise, Steve. Seeing as how both the ignition and injector pulse drop out in that band - = it would seem to me that the problem must lie in the circuit common to both= which is the CAS signal processing circuit. If only one pulse train, eith= er the ignition or the injector pulses only dropped out, then of course you= would suspect the respective circuit - but, this is common to both. On the other hand, rotor 1 continues to run - but, as you noted - the pulse= duration for even rotor 1 in this rpm range does not appear normal in tha= t range. I suspect that since your 1K ohm resistor (which brings the peak voltage do= wn to 6 volts) where it appears to run ok at that point, that for some re= ason the input circuitry has a problem handling the +13 volt peak in the 66= 0-1400 rpm range. Since this would fall in normal TTY signal range (used b= y the microprocessor), I suspect that perhaps due to some bandpass filter e= ffect of the components in the input circuit that the +13 volt peaks are ov= erdriving the input circuit within that rpm range. Adding the resistor ch= anges the bandpass frequency and puts it someplace (probably lower) out si= de your operating rpm range. But, again without knowledge of the input circuit and seeing what is reall= y going on inside the EC its difficult to say. Ed --_000_3E8191F276108F4481AB0721BBA9269E05DEF5BEponyexpressm10u_ Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable

Ed,

 

I tested the engine on the stand with variable resistor= s across each CAS yesterday. With the engine idling at about 1500 RP= M, less than 100 ohms resistance across either CAS would cause the e= ngine to quit completely. Resistances this low must decrease the voltage generated by the CAS to a value = too low for the controller to use. The engine would not start with 200 ohm = across one CAS and 1K ohm across the other. It didn't matter = which CAS had the lower resistance. The engine would start with 300 ohm across one CAS and 1K oh= m across the other. This makes sense since the CAS cannot generate a= very strong signal at cranking speed.

 

What doesn't make sense to me:

Starting with 1K resistance across each CAS, if the resistance on one CAS was increased to 69K, the en= gine would still run fine at 1500 RPM. If the resistance was increased to 6= 9K on the other CAS, the engine would only run on one rotor. It didn't matter which CAS = resistance was increased first.

 

With 1K resistance across one CAS, changi= ng the resistance of the other CAS from 69K back to 1K= by connecting a wire would sometimes cause the engine would miss what seem= ed to be one firing event. Again, there was no difference in the behavior of either CAS in this regar= d.

 

The conclusion seems to be that adding the 1K re= sistor to each CAS seems to be beneficial and the value of 1K= is not critical or on the threshold of causing other problems.

 

Steve

From: Rotary motors in aircraft [flyrotary@= lancaironline.net] on behalf of Ed Anderson [eanderson@carolina.rr.com]
Sent: Thursday, November 08, 2012 6:38 AM
To: Rotary motors in aircraft
Subject: [FlyRotary] Re: Renesis CAS & EC-2 upgrade?

Likewise, Steve.
 
Seeing as how both the ignition and injector puls= e drop out in that band - it would seem to me that the problem must lie in = the circuit common to both which is the CAS signal processing circuit. = ; If only one pulse train, either the ignition or the injector pulses only dropped out, then of course you would suspect = the respective circuit - but, this is common to both. 
 
On the other hand, rotor 1 continues to run - but= , as you noted - the pulse duration for even rotor  1 in this rpm= range does not appear normal in that range.
 
I suspect that since your 1K ohm resistor (which = brings the peak voltage down to  6 volts) where  it appears = to run ok at that point, that for some reason the input circuitry has a pro= blem handling the +13 volt peak in the 660-1400 rpm range.  Since this would fall in normal TTY signal range (used by the= microprocessor), I suspect that perhaps due to some bandpass filter effect= of the components in the input circuit that the +13 volt peaks are ove= rdriving the input circuit within that rpm range.   Adding the resistor changes the bandpass frequency &nbs= p;and puts it someplace (probably lower) out side your operating rpm range.=
 
 But, again without knowledge of the input c= ircuit and seeing what is really going on inside the EC its difficult to sa= y.
 
Ed
 
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