---------------------------------------------------------- Engines-List Digest Archive --- Total Messages Posted Fri 10/08/10: 3 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 06:47 AM - Re: Back On Line (William L. Paulin) 2. 07:26 AM - Re: Back On Line (n801bh@netzero.com) 3. 08:53 PM - Re: Question for all (Speedy11@aol.com) ________________________________ Message 1 _____________________________________ Time: 06:47:00 AM PST US From: "William L. Paulin" Subject: Re: Engines-List: Back On Line Thanks. All the aerobatics I have done has been set the prop & forget it... so I have been assuming the constant speed choice was only important for xc f light & cost. And I thought that inverted was better injected even w/o inve rted fuel & oil systems. Any idea of the actual first cost &/or maintenance cost differences - carb v injected & constant speed v fixed pitch ( weight diff too)? Bill Sent from my iPhone On Oct 7, 2010, at 11:13 PM, Kelly McMullen wrote: > 1. Injected allows finer tuning of the mixture, more balanced power betwee n cylinders and is less susceptible to any injuction icing if the airbox is p roperly designed with alternate air. That is an advantage in clouds. Carb is cheaper, is simpler, uses lower pressure pumps, but needs carb heat plumbed . However I don't think a carb works as well for inverted flight, but not ce rtain on that point. > 2. Constant speed gives better power for climb by maintaining best power r pm. On the other hand it is heavier and much more expensive than fixed pitch . You would need to ask RV group as to which is better for aerobatics and fo r wt and balance on that aircraft. > > > On Thu, Oct 7, 2010 at 7:53 PM, William L. Paulin wrote: > Question for all: > > My son & I are looking for an RV-8. Our mission is split between cross co untry (must be IFR) & light sport aerobatics. I am a 1500 hr pvt pilot & he is a Marine F-18 pilot. Our questions are: > > 1. What are the advantages & disadvantages of injected vs. Carbureted? > > 2. What are the advantages & disadvantages of a constant speed prop.? > > Thanks, > > Bill > > Sent from my iPhone > > > ========================== ========= ========================== ========= ========================== ========= ========================== ========= > ________________________________ Message 2 _____________________________________ Time: 07:26:26 AM PST US From: "n801bh@netzero.com" Subject: Re: Engines-List: Back On Line There a few things that need to be addressed here. A 'float' type carb will NOT work inverted. A pressure carb or fuel inje ction with the correct flop tube in the fuel tank is your only option. An engine with NO inverted oil system installed and placed up side down will starve the oil pick up tube instantly and bearing failure will qui cky follow. If you are going to do positive G manuevers then the motor does not know it is up side down and will continue to run.. One small mistake while p erforming any aerobatic move that lets the plane get into a negative G inverted position and your motor will not like it.... At ALL... As for the prop, constant speed is preferred for aerobatics but the fixe d pitch will work ok too. neither one is a deal breaker. Unlike the flo at carb and non inverted oil system motor. IMHO. do not archive Ben Haas N801BH www.haaspowerair.com ---------- Original Message ---------- From: "William L. Paulin" Subject: Re: Engines-List: Back On Line Thanks. All the aerobatics I have done has been set the prop & forget i t...so I have been assuming the constant speed choice was only important for xc flight & cost. And I thought that inverted was better injected even w/o inverted fuel & oil systems. Any idea of the actual first cost &/or maintenance cost differences - ca rb v injected & constant speed v fixed pitch ( weight diff too)? Bill Sent from my iPhone On Oct 7, 2010, at 11:13 PM, Kelly McMullen wrote: 1. Injected allows finer tuning of the mixture, more balanced power betw een cylinders and is less susceptible to any injuction icing if the airb ox is properly designed with alternate air. That is an advantage in clou ds. Carb is cheaper, is simpler, uses lower pressure pumps, but needs ca rb heat plumbed. However I don't think a carb works as well for inverted flight, but not certain on that point. 2. Constant speed gives better power for climb by maintaining best power rpm. On the other hand it is heavier and much more expensive than fixed pitch. You would need to ask RV group as to which is better for aerobat ics and for wt and balance on that aircraft. On Thu, Oct 7, 2010 at 7:53 PM, William L. Paulin wrot e: Question for all: My son & I are looking for an RV-8. Our mission is split between cross country (must be IFR) & light sport aerobatics. I am a 1500 hr pvt pilo t & he is a Marine F-18 pilot. Our questions are: 1. What are the advantages & disadvantages of injected vs. Carbureted? 2. What are the advantages & disadvantages of a constant speed prop.? Thanks, Bill Sent from my iPhone ======================== ===========a href="http://www.matronics.com/Navi gator?Engines-List">http://www.matronics.com/Navigator?Engines-List== ======================== =========ums.matronics.com">http://forums.matronics.co m======================== ===========http://www.matronics.com/contribution"> http://www.matronics.com/contribution============ ======================== ======================== -======================== ======================== ======================== ======================== ======================== ======================== ========= ____________________________________________________________ Mortgage Rates Hit 3.25% If you owe under $729k you probably qualify for Obama's Refi Program http://thirdpartyoffers.netzero.net/TGL3241/4caf28adbe084162f93st04vuc ________________________________ Message 3 _____________________________________ Time: 08:53:54 PM PST US From: Speedy11@aol.com Subject: Engines-List: Re: Question for all A Jarhead Target driver! And you're going to let him fly your airplane? Well, I guess if I let my F-22 driving son fly mine then maybe your RV can survive, too. But tell him no traps. I am of the opinion that the RV-8/8A airframe is optimized with the 180 HP O-360 engine and a fixed pitch cruise prop. I believe the aerodynamics of the airframe are such that adding power above 180 HP adds very little to the top end speed and moderately to climb ability. The 180 and fixed pitch combo keeps the weight low and fuel flow low while providing reasonable performance. HOWEVER, having said that, let me say it all depends. If you are using a turf or short runway, then a CS prop is important - as is additional HP. I have a MT 3 blade CS prop on an IO-390 and I am very happy with the configuration. The extra HP is available if needed and the CS prop climbs like an angel. I'm airborne solo in about 3-400 feet and I accelerate quickly to 115KIAS on the deck. A climb to pattern altitude then takes only 6-7 seconds with a final airspeed of about 95KIAS. I can get 184 KIAS at 1000' MSL, but it drinks a lot of gas. A 2 blade will go a bit faster. Cruise is about 165 KTAS at about 8.2 GPH. With my engine/prop I'm able to climb to FL240. Acro is easy with the 3 blade and 210 HP. A fixed pitch will require slightly more finesse to avoid overspeeding the engine on downlines. IFR in the plane is easiest with an autopilot. It is a challenge to hand fly IFR while shorting charts, tuning radios, making radio calls, etc. I've found I must be very organized to fly IFR. An autopilot makes the task much easier. It gives you time to turn your attention to those numerous things that are required in IFR. Add rain to the mix and an approach to mins and you'll have your hands full. The carbureted vs injected arguments by Kelly are on target. I have a ram air system for my injectior throttle body that will auto revert to filtered alternate air if the intake should be clogged by ice or a bird. The RV is ideal for local fun flying and any engine prop combo will work, but an injected, inverted fuel and oil engine with a CS prop is best. For CC IFR flying, I'd make sure to have a Primary ADI plus backup, IFR certified GPS, ILS, and a good autopilot. I've flown all spins and acro maneuvers except the hammerhead. I've flown CC from Daytona Beach to Burlington and back. The airplane is fun for all the above. Stan Sutterfield _www.rv-8a.net_ (http://www.rv-8a.net) Question for all: My son & I are looking for an RV-8. Our mission is split between cross coun try (must be IFR) & light sport aerobatics. I am a 1500 hr pvt pilot & he i s a Marine F-18 pilot. Our questions are: 1. What are the advantages & disadvantages of injected vs. Carbureted? 2. What are the advantages & disadvantages of a constant speed prop.? Thanks, Bill ------------------------------------------------------------------------------------- Other Matronics Email List Services ------------------------------------------------------------------------------------- Post A New Message engines-list@matronics.com UN/SUBSCRIBE http://www.matronics.com/subscription List FAQ http://www.matronics.com/FAQ/Engines-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/engines-list Browse Digests http://www.matronics.com/digest/engines-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.