hi jeff did you upgrade from a 1835 by any chance just wondered how much extra power you gained p ----- Original Message ----- From: <jeffyor...@qx.net> To: "KRnet" <kr...@mylist.net> Sent: Tuesday, November 22, 2005 10:35 PM Subject: Re: KR> Geared vs direct drive Turbo & my 2 cents
> I love this subject and have contemplated turbo charging my 2180 for quite > some time. I feel I have extensive knowledge of turbo charging systems as I > have done extensive amounts of turbo and turbo engine work on automobile > applications. > > However, and not to slight anyone here, I don't think I would ever consider > taking a turbo from one application and believe I could bolt it to my VW > 2180 or a Corvair engine and expect success. > > I cut my teeth in turbo experimenting with automobiles. I will also credit > much of the knowledge I gained came from many individuals involved in the > Shelby Dodge Auto Clubs. Here is what I learned. Or, I could just cut to the > finish and suggest that if you want to turbo your airplane, start with a > proven turbo and engine application and then make minor modifications as you > need. But back to what I learned. > > With a turbo several things are critical to it's success. > I would say that the most important is proper air fuel ratio delivery and > the ability to monitor that. In an aircraft , this would be highly critical. > I think more engines blow up ( turbo or normally aspirated) because they get > to a lean mixture condition. Adding a turbo makes this even more of an > issue. For that matter, anything that increases horsepower makes fuel > delivery very important. So, fuel injection would be my choice over a carb > on this subject. I would also install an air fuel meter. > > You would also need to deal with the great deal of increased heat that a > turbo creates. Both to your oil and probably even your air fuel mixture. > Cooling the air fuel mixture can be done with and intercooler. The increase > in oil temps would be a challenge to your oil cooler and oil delivery > system. You may also need to deal with the fact that when you shut off the > engine, all that hot oil from your turbo will drain down to your engine , > thus increasing oil temps after shut down. The most reliable automotive > turbo's use both oil and engine coolant to keep the turbo cool. > > You also need a reliable way to regulate the waste gate. Or in other words > you have to be able to keep the turbo from overboosting. Again, I believe > you need to monitor this with a guage. If not you will never be able to keep > head gaskets on your engine. You would also burn holes in the tops of your > pistons, burn valves and so on and so on. Speaking of valves, my experience > leads me to believe that you would need to change the exhaust valves on your > engine as well , in order to deal with the increased temps of combustion. > This goes back to the idea of starting with a reliable engine turbo > combination. > > I could go on and on with the subject of turbo charging. I would also say > that I think it is the cheapest and best way to get more ponies and torque > out of an engine. I also would guess that there are people on this list that > know 10 times more then me on turbo charging. But I qualify my information > with the years I spent experimenting with turbo in automobiles and that I > was able to take a 2.2 four cylinder engine of 140 horsepower and develop a > reliable dyno tested 360 HP with incredible amounts of torque. But, I did > this using a tried and tested engine and turbo combination. I was able to > take advantage of computerized controls for fuel delivery and waste gate > controls. I was able to write my own computerized fuel tables and timing > curves to assure air fuel mixture at various RPM ranges. This was all done > via Engine ECU and interfacing a laptop computer. And the whole system seems > a little complex for a KR2. I also need to mention that I struggled with all > the items mentioned above. No big deal when on the ground ( ok maybe a few > towing bills and head gaskets and parts and such) but I sure wouldn't want > to have those issues in the air. > > I would still like to turbo an engine for my KR2. I am still unsure of the > best, lightest and most reliable way to do it. Maybe I will start with some > Rev Master turbo parts and go from there. > > Jeff York > KR-2 Flying > N839BG > Home page http://web.qx.net/jeffyork40/ > My KR-2 http://web.qx.net/jeffyork40/Airplane/ to see my KR-2 > Email jeffyor...@qx.net > > ----- Original Message ----- > From: "hussein nagy" <nagy_ta...@yahoo.com> > To: <brokerpilot9...@earthlink.net>; "KRnet" <kr...@mylist.net> > Sent: Monday, November 21, 2005 7:40 PM > Subject: Re: KR> Geared vs direct drive > > > > Hello, Colin, > > I always enjoy you comments on subjects, I am an observer to the KRnet > , I bought a KR2 Boat with retractable gear and tail dragger, I have no > experience of building A/C but opinion of experienced folks count, Now let > ask you , I have the wing center Old aerfoil RAF48, Do you think the new > aerofoil is woth it at this stage of the built, and changing to fixed gear > better than the retract fo KR2, when the new aerfoil instaaled do you think > that the elevator and the rudder will be resized. would like to know your > opinion, > > Best regards > > Nagy > > Jacksinville, Florida > > 904-543-8183 > > > > Colin Rainey <brokerpilot9...@earthlink.net> wrote: Netters > > This debate about best engines for experimentals, and whether to turbo, > whether to Gear drive/PSRU or direct drive has been going on for a while > now, and I suspect will probably continue, kind like the Ford/Chevy debate > (Chevy is best, LOL ). I am NOT going to take sides of whether a builder > should choose auto or aircraft engine, normally aspirated or turbo, or > direct drive or PSRU. All these things are in the archives, and found in > literal volumes in other writings, both Internet and books like, "Auto > Engines for Experimental Airplanes" by Robert Finch, just to sight one > example. There are many others. > > > > What all Netters, especially you new members need to take to heart is > that engine selection is VERY important. Looking at certified aircraft, you > will see that it it the single most important factor when considering an > aircraft's present value, how many hours on the engine. Of all the expense > of owning an aircraft, once it is completed, the most money you will spend > will be for the engine, and its up keep/maintenance. Turbo charging is the > cats meow for cheap horsepower, but just ask Orma Robbins about how this > "enhancement" comes with its own unique set of problems to deal with and > overcome. Also, the article sighted states that turbo charging generally > adds at least 50% more power. This is out right fiction! The best that I > have seen proven by dyno runs is approximately 40%, and this is with > associated engine modifications, AND the use of an inter cooler, which is > not mentioned in the article at all. B&M, Vortech, Banks Turbo-charging, > and Paxton all report similar > > values for their "bolt-on" systems. I am not saying that a turbo or > supercharger cannot add 50% or more power, but that rather that bolt on > systems do not give that kind of increase, and do not want builders running > out and buying a turbo for their engine expecting to get a 50% increase in > power and torque by just hacking the exhaust in order to add the turbo. > > > > The same rules hold true for direct drive vs PSRU. There are definite > benefits to a PSRU, but to set one up on a 2.2 to 1 reduction, just to > achieve maximum horsepower from an engine from a dyno run, and say that is > best does not take into account all phases of flight for the engine, only > take off. That is the only time you will use max power. This amount of > reduction although it makes the max power available according to the dyno, > it does not allow for a reasonable rpm for cruise. This is because the prop > will be slowed to 2000 to 2100 rpm, which begins putting it below its > cruise efficiency speed. Just compare certified props that are made to run > in this range of rpms. They produce max thrust at near redline, and produce > best cruise thrust at 75 to 80% engine power. This puts the prop at around > 2300 to 2400 rpms on a 2750 redline. This puts the engine in the re drive > at 5060 rpms for the 2300, and 5280 rpms for the 2400 rpms at the prop. Now > your engine is running > > just like the Rotax family of engines and can expect the same life, or > simply 50 to 100 hour maintenance intervals with a major a max of 500 hours > out. It also makes the combination "peaky", where basically you spend > literally all your time at or near peak rpm. > > > > Robert Finch's book details a lot of engines that have been successfully > used in direct drive configuration; the Buick V8, the VW family, the > Corvairs, and several others mentioned in his book. In larger aircraft that > have more generous weight allowances for the engine, the more complicated > and heavier engines have a good appeal. BUT for our applications, in order > to stay in the RECOMMENDED weight range of engines AND their output, direct > drive offers the best answers, and air cooled the simplest installation. > Above all, it takes research and study to decide and engine install, and > talking to other actual pilots of those engines. Don't get sucked into the > trap of some fancy numbers calculations and good advertising on one web > page where one engine is presented as the experimental airplanes dream > engine. There are a lot of "assumptions" and over generalizations made at > the expense of the builder. No quick answers here. It takes years to build > a KR, take enough time to > > study your engine completely BEFORE spending any money. > > > > > > Colin Rainey > > brokerpilot9...@earthlink.net > > EarthLink Revolves Around You. > > _______________________________________ > > Search the KRnet Archives at http://www.maddyhome.com/krsrch/index.jsp > > to UNsubscribe from KRnet, send a message to krnet-le...@mylist.net > > please see other KRnet info at http://www.krnet.org/info.html > > > > > > > > > > nagy hussein > > > > --------------------------------- > > Yahoo! FareChase - Search multiple travel sites in one click. > > _______________________________________ > > Search the KRnet Archives at http://www.maddyhome.com/krsrch/index.jsp > > to UNsubscribe from KRnet, send a message to krnet-le...@mylist.net > > please see other KRnet info at http://www.krnet.org/info.html > > > > > > _______________________________________ > Search the KRnet Archives at http://www.maddyhome.com/krsrch/index.jsp > to UNsubscribe from KRnet, send a message to krnet-le...@mylist.net > please see other KRnet info at http://www.krnet.org/info.html > > > -- > No virus found in this incoming message. > Checked by AVG Free Edition. > Version: 7.1.362 / Virus Database: 267.13.4/176 - Release Date: 20/11/2005 > ---------------------------------------- I am using the free version of SPAMfighter for private users. It has removed 24549 spam emails to date. Paying users do not have this message in their emails. 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