KR>KR-2 Engine Choices
KRnetters, I appreciate all your inputs, on and off-line. Some folks are not English majors nor diplomats, but I do understand what you are telling me. I have also consulted with two aeronautical engineers this past weekend. I have concluded: My first question: Is an extra 25 hp worth an extra $9,000? An extra 25 hp, all other things considered equal, will result in a 10 percent speed increase. If I get 150 MPH with 75 hp, then I would get 165 MPH with 100 hp. Perhaps to some (or many) that is quite desirable, especially if money is no object. But then why are you building a KR aircraft? I want to build an economical performance airplane. I am not inclined to build my own engine. So, for me the answer is no. Second: Is an estimated extra 91 pounds empty weight on a KR-2 realistic? About 90 percent of this will be forward of the main spar and ahead of the firewall. My engineer friends estimate the gross weight will be 1050 pounds instead of 950 pounds. My KR-2 would have the CG at 0.2 inches ahead of the max forward CG from the plans at gross and 1.0 inch forward of max forward CG at VFR minimum fuel with just myself on board, no baggage. That was deemed flyable, but definitely not recommended. So, that answer is no. Third: How will the taller gear effect ground handling and flight characteristics? There would most likely be no discernable change in ground handling or flight characteristics with the taller gear. There was lots of concern for loading on the spar at the gear attach points due to increased strain from the longer gear legs especially during hard landings. Dan Diehl did recommend that I not use his aluminum castings with longer gear legs. The RG TT 2000 EFI is a wonderful engine development with the technology that I want. However, it is just not suitable for me and my KR-2. Others may find just the opposite for their aircraft, and I applaud them for their choice. I am opting for a direct-drive 2180 VW and standard Diehl tri-gear. Regards, Sid Wood, KR-2 N6242 Mechanicsville, MD sidney.w...@titan.com
KR>KR-2 Engine Choices
KRnetters, I am building a KR-2, converted to tri-gear from retract conventional gear. Dan Diehl gear legs are installed. It is time for an engine. My first choice was a 75 hp 2180 vw direct drive with electronic ignition from Steve Bennett. Full-up price ready to bolt on, including freight and wood prop is about $7,000. Then I came across www.vw-engines.com that were offering three sizes of vw with fuel injection. What looked about right for my KR-2 was a 2000 cc 100+ hp model RG 2000 with a geared redrive, fuel injection and electronic ignition. This engine is based on a type 4 Porsche engine. The weight with all accessories less a wood prop is 221 lbs. To effectively use this 100+ hp I will need a 58 inch diameter by 60 inch pitch prop. That means I need to raise the standing height another 3 inches for proper ground clearance. That means I need to replace the Diehl gear with longer gear from www.vw-engines.com . Also I must use a new bed-mount for the new nose gear and redrive engine, rebuild the fuel system to accommodate low pressure and high pressure fuel pumps, an anti-surge tank, tank selector to route return fuel to the wing tank being used, and possibly another fuel gauge for the anti-surge tank. The cowl will require several bumps for the fuel rails. The price quote from Australia is $13,980 US plus freight and customs to add about $700. Another $2,000 is estimated to do the airframe mods. My first question: Is an extra 25 hp worth an extra $9,000? Second: Is an estimated extra 91 pounds empty weight on a KR-2 realistic? About 90 percent of this will be forward of the main spar and ahead of the firewall. Third: How will the taller gear effect ground handling and flight characteristics? I would appreciate your help on this engine choice matter. Regards, Sid Wood, KR-2 N6242 Mechanicsville, MD sidney.w...@titan.com
KR>KR-2 Engine Choices
Sidney; With respect to (wrst) HP VS SPEED the ratio is one of cubes. eg the cube root of 75 hp is 4.2. that of 100 hp is 4.62. The ratio is 1.1. ie if 75 hp gives 150 mph 100 hp gives 165 mph. W.G.(Bill) KIRKLAND wkirkl...@rogers.com - Original Message - From: "Wood, Sidney M." <smw...@titan.com> To: "KRnet" <kr...@mylist.net> Sent: Thursday, February 26, 2004 1:28 PM Subject: KR>KR-2 Engine Choices KRnetters, I am building a KR-2, converted to tri-gear from retract conventional gear. Dan Diehl gear legs are installed. It is time for an engine. My first choice was a 75 hp 2180 vw direct drive with electronic ignition from Steve Bennett. Full-up price ready to bolt on, including freight and wood prop is about $7,000. Then I came across www.vw-engines.com that were offering three sizes of vw with fuel injection. What looked about right for my KR-2 was a 2000 cc 100+ hp model RG 2000 with a geared redrive, fuel injection and electronic ignition. This engine is based on a type 4 Porsche engine. The weight with all accessories less a wood prop is 221 lbs. To effectively use this 100+ hp I will need a 58 inch diameter by 60 inch pitch prop. That means I need to raise the standing height another 3 inches for proper ground clearance. That means I need to replace the Diehl gear with longer gear from www.vw-engines.com . Also I must use a new bed-mount for the new nose gear and redrive engine, rebuild the fuel system to accommodate low pressure and high pressure fuel pumps, an anti-surge tank, tank selector to route return fuel to the wing tank being used, and possibly another fuel gauge for the anti-surge tank. The cowl will require several bumps for the fuel rails. The price quote from Australia is $13,980 US plus freight and customs to add about $700. Another $2,000 is estimated to do the airframe mods. My first question: Is an extra 25 hp worth an extra $9,000? Second: Is an estimated extra 91 pounds empty weight on a KR-2 realistic? About 90 percent of this will be forward of the main spar and ahead of the firewall. Third: How will the taller gear effect ground handling and flight characteristics? I would appreciate your help on this engine choice matter. Regards, Sid Wood, KR-2 N6242 Mechanicsville, MD sidney.w...@titan.com ___ to UNsubscribe from KRnet, send a message to krnet-le...@mylist.net please see other KRnet info at http://www.krnet.org/info.html
KR>KR-2 Engine Choices
Sid, Do yourself a favor. Go with the "plug and chug". A 2180 from Steve is one of the best engines you can put on a KR2. If it were a 2S, then maybe, but I wouldn't change out that gear for anything. You will probably use up all that extra power pulling around the extra weight. See N64KR at http://KR-Builder.org - Then click on the pics Daniel R. Heath - Columbia, SC da...@kr-builder.org See you in Mt. Vernon - 2004 - KR Gathering See our EAA Chapter 242 at http://EAA242.org
KR>KR-2 Engine Choices
>My first question: Is an extra 25 hp worth an extra $9,000? Why would you do it? Reasons: operate out of a high altitude airport. want to climb fast don't care about fuel costs have too much money want to delay getting into the air >Second: Is an estimated extra 91 pounds empty weight on a KR-2 realistic? If you do not care to carry any passengers, or do not mind much higher stall and landings speeds, no problem. >About 90 percent of this will be forward of the main spar and ahead of the >firewall. You definitely will not be tail heavy, but you will need to consider a redesign of the engine mount to keep behind the forward limit. >Third: How will the taller gear effect ground handling and flight >characteristics? Ground visibility will be worse and handling should be more tender. Flight should not be impacted, other than more drag. Larry Severson Fountain Valley, CA 92708 (714) 968-9852 lar...@socal.rr.com
KR>KR-2 Engine Choices
Hi Stan: Knowing this net you will get lots of help with your decision. From my prospective, First, you must consider the construction of you firewall, will it take the extra. Second, the Type 4 is already heaver then the type 1/3 and by the time you add all the extra weight of the rear-drive and fuel pumps, I'll bet you have a total engine installation of over 300 pounds. You must also consider that the nose gear is also forward CG. All of the stuff you plan for the panel is also fwd CG. The basic KR was designed to fly 180 and have a useful load of 400 pounds. You probably already know that. Personally if I could up my HP to 100 and leave everything else as is , it still would not be worth that many extra bucks. If you can afford the price and want the extra power, why not consider going with the O-200 or Corviar. Orma L. Robbins Southfield MI 19 Years flying KR-2 N110LR http://www.aviation-mechanics.com
KR>KR-2 Engine Choices
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