X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from fmailhost02.isp.att.net ([204.127.217.102] verified) by logan.com (CommuniGate Pro SMTP 5.2.9) with ESMTP id 3235895 for flyrotary@lancaironline.net; Thu, 23 Oct 2008 11:21:02 -0400 Received-SPF: none receiver=logan.com; client-ip=204.127.217.102; envelope-from=keltro@att.net Received: from fwebmail09.isp.att.net ([204.127.218.109]) by isp.att.net (frfwmhc02) with SMTP id <20081023152023H02004ii88e>; Thu, 23 Oct 2008 15:20:24 +0000 X-Originating-IP: [204.127.218.109] Received: from [65.255.93.47] by fwebmail09.isp.att.net; Thu, 23 Oct 2008 15:20:23 +0000 From: "Kelly Troyer" To: "Rotary motors in aircraft" Subject: N613BX update Date: Thu, 23 Oct 2008 15:20:23 +0000 Message-Id: <102320081520.19434.490096360004EB4E00004BEA22218675169B0A02D29B9B0EBF019D9B040A05@att.net> In-Reply-To: X-Mailer: AT&T Message Center Version 1 (Jul 16 2008) X-Authenticated-Sender: a2VsdHJvQGF0dC5uZXQ= MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="NextPart_Webmail_9m3u9jl4l_19434_1224775223_0" --NextPart_Webmail_9m3u9jl4l_19434_1224775223_0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Great report Steve !!..............Perhaps Tracy will comment on your stag= ing fix.............=20 -- Kelly Troyer=20 "Dyke Delta"_13B ROTARY Engine=20 "RWS"_RD1C/EC2/EM2=20 "Mistral"_Backplate/Oil Manifold=20 -------------- Original message from "sboese" : ----------= ----=20 To anyone interested: The following is a response to Doug=E2=80=99s recent request for updates on= flying rotaries: In early June, having recovered sufficient courage to try another cross cou= ntry trip after feeding my prop to my tow bar (yes Ed, I still have the tow= bar) in Minnesota, we finally set out on another one in our 13B powered RV= -6A, this time to the west. After squeezing between the top of the control= led airspace and a cloud layer over Great Salt Lake, negotiating a narrow c= orridor which happened to be populated with scattered rain showers between= restricted airspaces, and a fuel stop in Wendover, UT, we crossed Mono Lak= e, the Sierra Mountains, and Yosemite Park at 14500 ft with 50 knot headwin= ds. Thumbing my nose at the concept of shock cooling, we descended over 11= ,000 ft in 25 miles and landed at our destination of Mariposa-Yosemite airp= ort. Other than a little initial roughness on bringing the power back up i= n the pattern after that descent, probably due to some lead fowling of the = plugs since 100 LL was the only suitable fuel available at Wendover, the en= gine installation behaved flawlessly. This is in contrast to the performan= ce of the pilot with the different sight picture at the slower ground speed= s at lower density altitude than I ever see at home in Laramie, WY, and the= inclined runway surrounded by hills at MPI. Thankfully, those details are= not rotary related however, and need not be expanded upon further. The friends we stayed with near Mariposa built an award-winning RV-6 with a= n O-360 and CS prop. While we were there, we took a couple of side trips w= ith the planes which gave the opportunity for some side by side comparisons= . Their take off and climb performance was much more impressive than ours = which was not surprising since our Performance Propellers fixed pitch prop = is set up primarily for cruise rather than climb. On one trip, after flyin= g a mile out over the Pacific at Monterrey Bay (just to say we did it) I s= et up the plane at max power and made the flight back to MPI under these co= nditions. Altitude was 5500 ft, fuel burn was 14.8-15 gal/hr, MAP was 23.8= =E2=80=9D, RPM was 5900, and IAS was 148 knots. I don=E2=80=99t know what = the OAT was, but it wasn=E2=80=99t out of the ordinary. Our friends report= ed burning close to 9 gal/hr while flying alongside us during this time. I= was somewhat surprised by this and one thing in particular came to mind: p= arasite drag. The attached picture was taken during this flight and two so= urces of drag can be readily seen: the large and sharp angled cooling air o= utlet, and the =E2=80=9Cbomb=E2=80=9D which is a muffler. The trip home was relatively uneventful and involved a detour over Mammoth = Lakes, CA to allow more time to climb and a lower altitude for crossing the= Sierras. At the fuel stop at Wendover, I discovered a crack in one of the= braces between the rear of the engine and the exhaust header, but this was= n=E2=80=99t a particular cause for worry since I had flown for more than 40= hrs before even installing the two of those. Since we did not have headwi= nds on the return trip, the total flight time home was an hour less than th= e flight time out. The landing in Laramie was in conditions not uncommon t= o this area, landing on runway 21 with the ASOS reporting winds from 250 de= grees at 22 gusting to 30. Thankfully, I had completed a flight review usi= ng our plane just a few days before starting the trip and crosswind techniq= ue was one of the things developed. At least this was the last stop becaus= e the seat was definitely at risk of being soiled. After returning home, a drag reduction attempt was made by cutting away muc= h of the bottom of the lower cowling and reshaping the cooling air outlet t= o be much more similar to the original shape as supplied by Van=E2=80=99s. = This cut the outlet area approximately in half to 77 sq in which is still = larger than that in the unmodified original cowling. This configuration is= shown in another attached photo. Tuft testing showed no turbulent areas e= xcept for one tuft right behind the exhaust header outlet. Test flights at= max power were conducted with and without the =E2=80=9Cbomb=E2=80=9D.=20= =20 Without the muffler: 163 knot TAS at 11500 ft DA, 12.4 gal/hr fuel fl= ow, 5800 rpm, 19.9=E2=80=9D MAP With the muffler: 160 knot TAS at 11500 ft DA, 12.2 gal/hr fuel = flow, 5750 rpm. 20.2=E2=80=9D MAP The 3 knot penalty is a small price to pay since the noise level without th= e muffler is unbearable for any length of time. Cooling is still satisfactory but under cowl temperatures are higher (~160 = deg F) than before as would be expected with decreased cooling air mass flo= w. An enclosure was constructed around the stock Mazda ignition coils and = a blast tube installed from the oil cooler air inlet to this enclosure whic= h keeps the coils at less than 110 deg F.=20=20 Several other changes have been made since first flight over two years ago: One is the elimination of the cowling combustion air inlet (snorkel) and fi= ltered air box as originally supplied by Van=E2=80=99s. A NACA duct inlet = and air filter was installed in the cowling side very near the throttle bod= y. This eliminated the over 3 foot long 3.25 inch diameter skeet duct from= the air box to the throttle body. This was done to avoid the heating of t= he air while inside this duct which resulted in temperatures of the air ent= ering the throttle body in excess of 110 degrees F in flight regardless of = the OAT. Now, the air entering the throttle body remains within 2 degrees = F of the OAT. The result is a lower Density altitude seen by the engine.= =20=20 =20=20=20=20 Another change was the elimination of the vacuum system which included the = DG, AI, Mazda smog pump used as the vacuum pump, vacuum regulator, and asso= ciated tubes and filters. In place of the smog pump, a second alternator w= as installed. The second alternator led me to eliminate the second PC680 b= attery. The instrumentation was replaced by a Dynon D10A EFIS. A net weig= ht decrease of 19 lb was realized by these changes. =20=20=20=20 One other change that I made before the CA trip involved problems I had wit= h tuning the system to transition the injector staging point without hesita= tion or misfiring of the engine. This had always been of only slight conce= rn until during one flight when advancing the throttle after a stall, the e= ngine hung up and didn=E2=80=99t produce full power for almost 10 seconds. = As best as I can remember since some sense of panic ensued, first backing = off the throttle position significantly from full did not clear the conditi= on, but tweaking the mixture control did. The behavior seemed somewhat si= milar to SAG as described by others on this list, but I could not correlate= the event to spark plug condition. Further attempts at tuning the mixture= table in the staging region were unsuccessful at eliminating this behavior= . As also described as having been tried by others on this list, I tried t= o pneumatically filter the manifold pressure input to the EC2 using fuel fi= lters and various sized orifices in the lines between the plenum and EC2. = It was possible to induce surging with orifices of too small opening, but t= he staging difficulty was not improved with various combinations of reservo= ir and orifice size. During these tests, I found that by proper (improper?= ) manipulation of the throttle, I could repeatedly induce the extended lack= of power increase on injector staging. Data recorded by my monitoring sys= tem clearly showed the rpm plateau persisting while changing manifold press= ure with the throttle, average fuel flow consistent with the associated MAP= at any given instant, and a lean condition as shown by both O2 sensors. = Since the fuel flow was reasonable, the excess O2 could result from ineffec= tive ignition: fuel was there, but not being burned and using up the O2. = No faults with the ignition system could be found by tests including among = others checking the ignition timing and using new spark plugs and wires. S= ince the condition could be induced by changing=20manifold pressure, I post= ulated that the manifold pressure as seen by the EC2 may be unstable or unr= eliable. Searching the Motorola literature on the sensors used in the EC2,= I found a reference to additional components recommended to be installed o= n the sensor output if the output is connected to an A/D converter. In des= peration, I installed these components into my EC2 and immediately the misb= ehavior on staging disappeared. I have not been able to induce it again no= matter how hard I try. My theory is that under certain conditions, the MA= P sensor output goes into oscillation which may or may not persist dependin= g on the circumstances. I have not verified this by bringing the output si= gnals external to the EC2 to an oscilloscope since if they are subject to i= nstability, doing so may provide more questions than answers. I have prett= y much kept this under my hat to this point, but enough time on this change= has been accumulated that I am comfortable that the change is not detrimen= tal at least. I certainly do NOT recommend or encourage changes to the EC2= without Tracy=E2=80=99s input without fully accepting the risks. I have n= o proof that my interpretation of the events related above is correct, simp= ly that it helped in my individual case.=20=20=20=20=20=20=20=20=20=20=20= =20 I had hoped to make it to the roundup this year, having bought the charts, = planned the flight and arranging time off. The front that Bill managed to = cross was too much to try to take on from this far away. So here I sit wat= ching the blowing snow outside wishing that I had made it to the roundup an= d that the front had materialized after getting there and thus preventing m= y return. One additional note for those who made it this far. I=E2=80=99ve been spen= ding considerable time in our local ice cream parlor in an attempt to maint= ain a constant system in-flight gross weight after the elimination of the h= ardware as described above.=20=20 OOOOH the sacrifices one has to make in the name of research=E2=80=A6.=20= =20 Steve Boese RV-6A, 1986 13B NA, EC2, RD1A =E2=80=A6 --NextPart_Webmail_9m3u9jl4l_19434_1224775223_0 Content-Type: multipart/related; boundary="NextPart_Webmail_9m3u9jl4l_19434_1224775223_1" --NextPart_Webmail_9m3u9jl4l_19434_1224775223_1 Content-Type: text/html; charset="utf-8" Content-Transfer-Encoding: quoted-printable
 Great report Steve !!..............Perhaps Tracy will comment on= your staging fix............. 
--
Kelly Troyer
"Dyke Delta"_1= 3B ROTARY Engine
"RWS"_RD1C/EC2/EM2
"Mistral"_Backplate/Oil Manifol= d



 
-------------- Original message from "sboese" <sboese@uwy= o.edu>: --------------

<= SPAN style=3D"FONT-SIZE: 12pt; COLOR: navy">To anyone interested:

 <= /P>

The following is a re= sponse to Doug=E2=80=99s recent request for updates on flying rotaries:

 <= /P>

In early June, having= recovered sufficient courage to try another cross country trip after feedi= ng my prop to my tow bar (yes Ed, I still have the tow bar) in Minnesota, w= e finally set out on another one in our 13B powered RV-6A, this time to the= west.  After squeezing between the top of the controlled airspace and= a cloud layer over Great Salt Lake, negotiating a narrow corridor which ha= ppened to be  populated with scattered rain showers between restricted= airspaces, and a fuel stop in Wendover, UT, we crossed Mono Lake, the Sier= ra Mountains, and Yosemite Park at 14500 ft with 50 knot headwinds.  T= humbing my nose at the concept of shock cooling, we descended over 11,000 f= t in 25 miles and landed at our destination of Mariposa-Yosemite airport.&n= bsp; Other than a little initial roughness on bringing the power back up in= the pattern after that descent,=20probably due to some lead fowling of the= plugs since 100 LL was the only suitable fuel available at Wendover, the e= ngine installation behaved flawlessly.  This is in contrast to the per= formance of the pilot with the different sight picture at the slower ground= speeds at lower density altitude than I ever see at home in Laramie, WY, a= nd the inclined runway surrounded by hills at MPI.  Thankfully, those = details are not rotary related however, and need not be expanded upon furth= er.

 <= /P>

The friends we stayed= with near Mariposa built an award-winning RV-6 with an O-360 and CS prop.&= nbsp; While we were there, we took a couple of side trips with the planes w= hich gave the opportunity for some side by side comparisons.  Their ta= ke off and climb performance was much more impressive than ours which was n= ot surprising since our Performance Propellers fixed pitch prop is set up p= rimarily for cruise rather than climb.  On one trip, after flying a mi= le out over the Pacific at Monterrey Bay (just to say we did it)  I se= t up the plane at max power and made the flight back to MPI under these con= ditions.  Altitude was 5500 ft, fuel burn was 14.8-15 gal/hr, MAP was = 23.8=E2=80=9D, RPM was 5900, and IAS was 148 knots.  I don=E2=80=99t k= now what the OAT was, but it wasn=E2=80=99t out of the ordinary.  Our = friends reported burning close to 9 gal/hr while flying alongside us during= this time.  I was somewhat surprised by this and one thing in particu= lar came to mind: parasite drag.  The attached picture was taken durin= g this flight and two sources of drag can be readily seen: the large and sh= arp angled cooling air outlet, and the =E2=80=9Cbomb=E2=80=9D which is a mu= ffler.

 <= /P>

The trip home was rel= atively uneventful and involved a detour over Mammoth Lakes, CA to allow mo= re time to climb and a lower altitude for crossing the Sierras.  At th= e fuel stop at Wendover, I discovered a crack in one of the braces between = the rear of the engine and the exhaust header, but this wasn=E2=80=99t a pa= rticular cause for worry since I had flown for more than 40 hrs before even= installing the two of those.  Since we did not have headwinds on the = return trip, the total flight time home was an hour less than the flight ti= me out.  The landing in Laramie was in conditions not uncommon to this= area, landing on runway 21 with the ASOS reporting winds from 250 degrees = at 22 gusting to 30.  Thankfully, I had completed a flight review usin= g our plane just a few days before starting the trip and crosswind techniqu= e was one of the things developed.  At least this was the last stop be= cause the seat was definitely at risk of being soiled.

 <= /P>

After returning home,= a drag reduction attempt was made by cutting away much of the bottom of th= e lower cowling and reshaping the cooling air outlet to be much more simila= r to the original shape as supplied by Van=E2=80=99s.  This cut the ou= tlet area approximately in half to 77 sq in which is still larger than that= in the unmodified original cowling.  This configuration is shown in a= nother attached photo.  Tuft testing showed no turbulent areas except = for one tuft right behind the exhaust header outlet.  Test flights at = max power were conducted with and without the =E2=80=9Cbomb=E2=80=9D. =

   &nb= sp; Without the muffler:  163 knot TAS at 11500 ft DA, 12.4 gal/hr fue= l flow, 5800 rpm, 19.9=E2=80=9D MAP

   &nb= sp;     With the muffler:   160 knot TAS at 1= 1500 ft DA, 12.2 gal/hr fuel flow, 5750 rpm. 20.2=E2=80=9D MAP

The 3 knot penalty is= a small price to pay since the noise level without the muffler is unbearab= le for any length of time.

Cooling is still sati= sfactory but under cowl temperatures are higher (~160 deg F) than before as= would be expected with decreased cooling air mass flow.  An enclosure= was constructed around the stock Mazda ignition coils and a blast tube ins= talled from the oil cooler air inlet to this enclosure which keeps the coil= s at less than 110 deg F. 

 <= /P>

Several other changes= have been made since first flight over two years ago:

 <= /P>

One is the eliminatio= n of the cowling combustion air inlet (snorkel) and filtered air box as ori= ginally supplied by Van=E2=80=99s.  A NACA duct inlet and air filter w= as installed in the cowling side very near the throttle body.  This el= iminated the over 3 foot long 3.25 inch diameter skeet duct from the air bo= x to the throttle body.  This was done to avoid the heating of the air= while inside this duct which resulted in temperatures of the air entering = the throttle body in excess of 110 degrees F in flight regardless of the OA= T.  Now, the air entering the throttle body remains within 2 degrees F= of the OAT.  The result is a lower Density altitude seen by the engin= e.  

    

Another change was th= e elimination of the vacuum system which included the DG, AI, Mazda smog pu= mp used as the vacuum pump, vacuum regulator, and associated tubes and filt= ers.  In place of the smog pump, a second alternator was installed.&nb= sp; The second alternator led me to eliminate the second PC680 battery.&nbs= p; The instrumentation was replaced by a Dynon D10A EFIS.  A net weigh= t decrease of 19 lb was realized by these changes.

    

One other change that= I made before the CA trip involved problems I had with tuning the system t= o transition the injector staging point without hesitation or misfiring of = the engine.  This had always been of only slight concern until during = one flight when advancing the throttle after a stall, the engine hung up an= d didn=E2=80=99t produce full power for almost 10 seconds.  As best as= I can remember since some sense of panic ensued, first backing off the thr= ottle position significantly from full did not clear the condition, but twe= aking the mixture control did.   The behavior seemed somewhat sim= ilar to SAG as described by others on this list, but I could not correlate = the event to spark plug condition.  Further attempts at tuning the mix= ture table in the staging region were unsuccessful at eliminating this beha= vior.  As also described as having been tried by others on this list, = I tried to pneumatically filter the manifold pressure input to the EC2 usin= g fuel filters and various sized orifices in the lines between the plenum a= nd EC2.  It was possible to induce surging with orifices of too small = opening, but the staging difficulty was not improved with various combinati= ons of reservoir and orifice size.  During these tests, I found that b= y proper (improper?) manipulation of the throttle, I could repeatedly induc= e the extended lack of power increase on injector staging.  Data recor= ded by my monitoring system clearly showed the rpm plateau persisting while= changing manifold pressure with the throttle, average fuel flow consistent= with the associated MAP at any given instant,  and a lean condition a= s shown by both O2 sensors.  Since the fuel flow was reasonable, the e= xcess O2 could result from ineffective ignition:  fuel was there, but = not being burned and using up the O2.  No faults with the ignition sys= tem could be found by tests including among others checking the ignition ti= ming and using new spark plugs and wires.  Since the condition could b= e induced by changing manifold pressure, I postulated that the manifold pre= ssure as seen by the EC2 may be unstable or unreliable.  Searching the= Motorola literature on the sensors used in the EC2, I found a reference to= additional components recommended to be installed on the sensor output if = the output is connected to an A/D converter.  In desperation, I instal= led these components into my EC2 and immediately the misbehavior on staging= disappeared.  I have not been able to induce it again no matter how h= ard I try.  My theory is that under certain conditions, the MAP sensor= output goes into oscillation which may or may not persist depending on the= circumstances.  I have not verified this by bringing the output signa= ls external to the EC2 to an oscilloscope since if they are subject to inst= ability, doing so may provide more questions than answers.  I have pre= tty much kept this under my hat to this point, but enough time on this chan= ge has been accumulated that I am comfortable that the change is not detrim= ental at least.  I certainly do NOT recommend or encourage changes to = the EC2 without Tracy=E2=80=99s input without fully accepting the risks.&nb= sp; I have no proof that my interpretation of the events related above is c= orrect, simply that it helped in my individual case.    &nbs= p;       

 <= /P>

I had hoped to make i= t to the roundup this year, having bought the charts, planned the flight an= d arranging time off.  The front that Bill managed to cross was too mu= ch to try to take on from this far away.  So here I sit watching the b= lowing snow outside wishing that I had made it to the roundup and that the = front had materialized after getting there and thus preventing my return.

 <= /P>

One additional note f= or those who made it this far.  I=E2=80=99ve been spending considerabl= e time in our local ice cream parlor in an attempt to maintain a constant s= ystem in-flight gross weight after the elimination of the hardware as descr= ibed above. 

 <= /P>

OOOOH the sacrifices = one has to make in the name of research=E2=80=A6.  

 <= /P>

Steve Boese

RV-6A, 1986 13B NA, E= C2, RD1A =E2=80=A6

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