---------------------------------------------------------- RV8-List Digest Archive --- Total Messages Posted Fri 08/20/10: 5 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 04:57 AM - Re: Re: RV8-List Digest: 3 Msgs - 08/18/10 (Gordon or Marge) 2. 07:02 AM - Re: RV Speeds (Bill Judge) 3. 07:24 PM - Re: RV Speeds (Speedy11@aol.com) 4. 09:51 PM - Performance Numbers - IO-390/Hartzell/RV-8 (Matt Dralle) 5. 09:58 PM - RV-8 - Performance Numbers - IO-390/Hartzell/RV-8 (Matt Dralle) ________________________________ Message 1 _____________________________________ Time: 04:57:45 AM PST US From: "Gordon or Marge" Subject: RE: RV8-List: Re: RV8-List Digest: 3 Msgs - 08/18/10 -----Original Message----- From: owner-rv8-list-server@matronics.com [mailto:owner-rv8-list-server@matronics.com] On Behalf Of Speedy11@aol.com Sent: Thursday, August 19, 2010 8:01 PM Subject: RV8-List: Re: RV8-List Digest: 3 Msgs - 08/18/10 Yes - but not 6 knots different. Stan You have different props, right? Gordon Comfort Stan: It might be possible. I know of one comparison on a Lancair 360 that originally had the Hartzell prop specifically for that aircraft, two blades, relatively short. When a three blade MT was installed it was found that the MT produced better initial acceleration and climb but top speed fell by 6 to 8 knots. I cannot vouch for the rigor of the testing but I can say that the man who told me of this was a Lancair employee who did a lot of test flying and demo flying for Lancair and who's powers of observation were pretty good. As to to comments by others on the James cowl and plenum, I am not persuaded that the James system offers any real advantages over a well done conventional cooling system. Note the "well done". Smith did not use a plenum on his Oshkosh 500 racer even though he was well aware of the arguments for and against. The round openings certainly work well but claims that they are somehow inherently better seem to me to be unfounded. The major reason the Raspet Center used round inlets in their cooling drag development work was that they are easier to calculate. It would be interesting to know if anyone out there has done any systematic comparison testing. Gordon ________________________________ Message 2 _____________________________________ Time: 07:02:07 AM PST US From: Bill Judge Subject: RV8-List: Re: RV Speeds Does anyone have a comparison of the Aerocomposites vs Whirlwind on the same airframe? I've heard that the WW is faster/more efficient but I'm biased. I've got a WW 200RV, RV-8, Superior Airparts IO-360 w/ Ryton exploding sump, lightspeed II ignition and I generally run 160 knots TAS 10,000 feet, 6.5 gph, WOT, LOP, 1950 RPM. Everything else about the airframe is pretty much standard. I'm very confident in that 6.5 GPH @ 160 knots TAS figure. I'm not as confident in other power setting since I generally just run in the econo cruise @ 160. As the fuel burns off I generally pick up 2-3 knots from the reduced weight. I know that for keeping the efficiency up the low RPM is key. Thanks, Bill judge, RV-8, N84WJ 515 Hrs rv-8.blogspot.com > > Time: 11:23:12 AM PST US > Subject: Re: RV8-List: Re: RV Speeds > From: Richard Martin > > Stan, > I hate to tell you this, but your inability to achieve the higher speeds is > to sell your 3 blade MT to some one you do not like, and use the proceeds to > buy either the New blended airfoil blade Hartzell from Vans AC, or better > yet, buy a Aerocomposites 2 blade 72 or 74 inch propeller. Also, you could > contact Same James and consider one of his cowlings and plenum chambers > (proven speed prudecers). Good luck. > Dick Martin > RV8 N233M > the fast one > ________________________________ Message 3 _____________________________________ Time: 07:24:16 PM PST US From: Speedy11@aol.com Subject: RV8-List: Re: RV Speeds Dick, You gave me the same advice standing in my hangar last Jan. Told you then I don't plan to change the prop. I'm going to experiment with reducing the size of the Van's inlets (ala Dave Anders) to see if I can gain anything. But, I'm not willing to toss my cowling and put on the James cowling. My homemade plenum is working great. CHTs are well under control and Oil temp is perfect at 180. I did take your advice to straighten out the exhaust pipes for some jet effect. I don't notice any difference. Except the exhaust is hitting the bottom of the plane. Are you coming to FL for the winter? Stan Sutterfield I hate to tell you this, but your inability to achieve the higher speeds is to sell your 3 blade MT to some one you do not like, and use the proceeds to buy either the New blended airfoil blade Hartzell from Vans AC, or better yet, buy a Aerocomposites 2 blade 72 or 74 inch propeller. Also, you could contact Same James and consider one of his cowlings and plenum chambers (proven speed prudecers). Good luck. Dick Martin ________________________________ Message 4 _____________________________________ Time: 09:51:59 PM PST US From: Matt Dralle Subject: RV8-List: Performance Numbers - IO-390/Hartzell/RV-8 Dear Listers, So I could smell the disbelief in the air regarding my performance claims, so tonight after work I went up and did some testing. All tests were at the same altitude with the autopilot on, going the same direction (mostly South) with a Westerly wind over about the same 25 mile area. One interesting thing that I noticed tonight that I hadn't in the past was what a dramatic effect exacting leaning could have on the speed for a given power/prop setting. A small adjustment in the mixture could increase or decrease the speed sometimes as much as 5 MPH. Below is a table of the numbers I saw tonight. I've include the spreadsheet as well as photos of each setting from the EFIS PDF/Engine data. All numbers on the EFISs are in MPH. The GPS GS is in the upper left corner of the PFD. The TAS is on the bottom right side of the PFD display. Indicated is on the left side in the middle of the PFD. Temp is in the upper left corner of the Eng display. MAP, RPM, and Flow are also on the Eng display shown as gauges with text. An interesting thing I noticed that at 27.x MAP, adjusting the RPM between 2000 and 2690 had a 9.8 to 17.0 impact of fuel flow (7.2 GPH) and a 22MPH impact on speed. That's about a $32/hr difference. Emacs! Let the discussion begin... ;-) Matt Dralle RV-8 #82880 N998RV http://www.mattsrv8.com - Matt's RV-8 Construction Blog http://www.youtube.com/MattsRV8 - Matt's RV-8 HDTV YouTube Channel Status: Enjoying The Fruits of 2500 Hours of Labor! ________________________________ Message 5 _____________________________________ Time: 09:58:01 PM PST US From: Matt Dralle Subject: RV8-List: RV-8 - Performance Numbers - IO-390/Hartzell/RV-8 Dear Listers, I posted some performance number on the RV-List email forum the other day and based on the responses, I could smell the disbelief in the air regarding my claims. So, tonight after work I went up and did some testing. All tests were at the same altitude with the autopilot on, going the same direction (mostly South) with a Westerly wind over about the same 25 mile area. One interesting thing that I noticed tonight that I hadn't in the past was what a dramatic effect exacting leaning could have on the speed for a given power/prop setting. A small adjustment in the mixture could increase or decrease the speed sometimes as much as 5 MPH. Below is a table of the numbers I saw tonight. I've include the spreadsheet as well as photos of each setting from the EFIS PDF/Engine data. All numbers on the EFISs are in MPH. The GPS Ground Speed is in the upper left corner of the PFD. The True Airspeed is on the bottom right side of the PFD display. Indicated Speed is on the left side in the middle of the PFD. Temp is in the upper left corner of the Eng display. MAP (Manifold Pressure), RPM, and Flow are also on the Engine display shown as gauges with text. An interesting thing I noticed was that at 27.x MAP, adjusting the RPM between 2000 and 2690 had a 9.8 to 17.0 impact of fuel flow (7.2 GPH) and a 22 MPH impact on speed. That's about a $32/hr difference. Emacs! Matt Dralle RV-8 #82880 N998RV http://www.mattsrv8.com - Matt's RV-8 Construction Blog http://www.youtube.com/MattsRV8 - Matt's RV-8 HDTV YouTube Channel Status: Enjoying The Fruits of 2500 Hours of Labor! ------------------------------------------------------------------------------------- Other Matronics Email List Services ------------------------------------------------------------------------------------- Post A New Message rv8-list@matronics.com UN/SUBSCRIBE http://www.matronics.com/subscription List FAQ http://www.matronics.com/FAQ/RV8-List.htm Web Forum Interface To Lists http://forums.matronics.com Matronics List Wiki http://wiki.matronics.com Full Archive Search Engine http://www.matronics.com/search 7-Day List Browse http://www.matronics.com/browse/rv8-list Browse Digests http://www.matronics.com/digest/rv8-list Browse Other Lists http://www.matronics.com/browse Live Online Chat! http://www.matronics.com/chat Archive Downloading http://www.matronics.com/archives Photo Share http://www.matronics.com/photoshare Other Email Lists http://www.matronics.com/emaillists Contributions http://www.matronics.com/contribution ------------------------------------------------------------------------------------- These Email List Services are sponsored solely by Matronics and through the generous Contributions of its members.