KR> Ercoup flying
I owned my ercoupe for quite a number of years and put hundreds of hours in it. The limited elevator was but apart of it. The controls were another very big part of it. Also there were no springs between them. There was a mixing bellcrank under the baggage bag. It was all hard connected with rod end bearings and had a very specific rigging procedure. I completely rebuilt mine in about 1986. It had a lot of dihedral and was capable of a lot of crosswind. Very easy to land, but still a lot of fun. Sent from my iPhone On Jan 31, 2014, at 12:21 PM, Larry Flesner wrote: > At 01:03 PM 1/31/2014, you wrote: >> but the 'coupe had spring-mediated control linkage between the rudder and >> ailerons which provided automatic control coordination. This worked very >> well to prevent the cross-control stall problem, but made crabbing into a >> cross wind and slipping more difficult...not impossible. > > > The cross-control stall was eliminated by limiting elevator travel so you > could not stall the main wing, not through interconnected controls. The > Tripacer has interconnected aileron and rudder also but it will stall because > of greater elevator limits. The Tripacer controls are spring connected so > you can override either control with the other. Because you have no > independent rudder in an Ercoupe, you can't slip and must land in a crab in a > crosswind landing. The gear is beefed up to handle greater side loads. > Because it has tricycle gear, it straightens itself out from a crabbed > touchdown. Nice ideas for safety but basically makes it a mini van for sport > flying. :-) It really seams "unnatural" to drive an Ercoupe down the taxi > way using the control wheel, just like in a car. It just ain't > right... > > Larry Flesner > P.S. I seem to recall that if you got your license in a two control Ercoupe, > you were not licensed to fly a three control without further training / sign > off / etc. > > > ___ > Search the KRnet Archives at http://tugantek.com/archmailv2-kr/search. > To UNsubscribe from KRnet, send a message to KRnet-leave at list.krnet.org > please see other KRnet info at http://www.krnet.org/info.html > see http://list.krnet.org/mailman/listinfo/krnet_list.krnet.org to change > options
KR> Pressure testing my wing tanks
I'm a propane tech here on my island, and we use soapy water in a spray bottle to detect any gas leaks in the plumbing. Low pressures are a few inches of water here, so this is a very sensitive leak-detector and localizer. Peter You could alternatively pressurize the tank with nitrogen and then use a refrigerant sniffer to go over all the seams. It will find the smallest of leaks quickly and easily.
KR> Building the Wing Off the Plane?
Your main challenge on a KR is stall speed. If you don't build it very light, I do not think you will be able to meet this requirement. Remember this is "clean" stall, no flaps. Dan Heath > On Jan 31, 2014, at 11:35 AM, Dj Merrill wrote: > >> On 01/31/2014 02:21 AM, Mike T wrote: >> These two designs aren't as far >> apart as they seem, because a KR-2 can also be LSA compliant. It already >> makes the LSA stall speed if you keep it light, and I could use a smaller >> VW engine (or just adjust the throttle so the carb doesn't open all the >> way) to get it down to the LSA top speed someday. I think the LSA law >> would le me fly the plane fast for now, then slow it down to make it LSA >> compliant if I ever get sick of getting medicals. > > > Just a clarification, but the LSA rules will not let you fly it fast now > and then slow it down to LSA specs. The rules say that the aircraft > must ALWAYS have met LSA specs in order for a Sport Pilot to fly the > aircraft, or a private pilot not requiring a medical. > > You also would not need to put a throttle stop on the carb, or use a > smaller VW engine. The LSA rules say that it can't exceed 120 kts "with > maximum CONTINUOUS power". As the aircraft manufacturer, you can define > the maximum speed allowed, and you can label the panel with the max RPM > in level flight, which may be lower than the max RPM that the engine is > capable of. This allows you to use full power for takeoff and climb, > and only have to throttle back once you are at your cruising altitude. > There are existing aircraft that do this, including the infamous Carbon > Cub with its 180 hp engine: > > http://www.cubcrafters.com/carboncubss > > Note at the bottom of that page: > > "180 Horsepower for takeoff and climb up to 5 minutes - 80 Horsepower > for continuous operation. It is the pilots responsibility to operate the > aircraft in accordance with the pilot operating handbook and aircraft > placarding. There is NO governor or limiting system that controls the > engines power settings" > > > Here is an overview of the LSA regs if you are curious: > > http://www.sportpilot.org/learn/final_rule_synopsis.html > > -Dj > > > -- > Dj Merrill - N1JOV - VP EAA Chapter 87 > Sportsman 2+2 Builder #7118 N421DJ - http://deej.net/sportsman/ > Glastar Flyer N866RH - http://deej.net/glastar/ > > ___ > Search the KRnet Archives at http://tugantek.com/archmailv2-kr/search. > To UNsubscribe from KRnet, send a message to KRnet-leave at list.krnet.org > please see other KRnet info at http://www.krnet.org/info.html > see http://list.krnet.org/mailman/listinfo/krnet_list.krnet.org to change > options
KR> Ercoup flying
I've never flown one, but the 'coupe had spring-mediated control linkage between the rudder and ailerons which provided automatic control coordination. This worked very well to prevent the cross-control stall problem, but made crabbing into a cross wind and slipping more difficult...not impossible. The benefit of good design eliminating pilot error is incredible.(witness the cessna fuel system) and can extend to the broadest level of design...the B-33 Debonair practically lands itself, and this has saved many a dollar for tired pilots at the end of long cross-country flights. The plane has 80 gal tanks, and can safely travel for 6 1/2 hrs. You can't believe how hard it can be to land at night after dehydrating at 12.5k ft. all afternoon and into the darkness. Peter
KR> Ercoup flying
At 01:03 PM 1/31/2014, you wrote: >but the 'coupe had spring-mediated control linkage between the >rudder and ailerons which provided automatic control coordination. >This worked very well to prevent the cross-control stall problem, >but made crabbing into a cross wind and slipping more >difficult...not impossible. The cross-control stall was eliminated by limiting elevator travel so you could not stall the main wing, not through interconnected controls. The Tripacer has interconnected aileron and rudder also but it will stall because of greater elevator limits. The Tripacer controls are spring connected so you can override either control with the other. Because you have no independent rudder in an Ercoupe, you can't slip and must land in a crab in a crosswind landing. The gear is beefed up to handle greater side loads. Because it has tricycle gear, it straightens itself out from a crabbed touchdown. Nice ideas for safety but basically makes it a mini van for sport flying. :-) It really seams "unnatural" to drive an Ercoupe down the taxi way using the control wheel, just like in a car. It just ain't right... Larry Flesner P.S. I seem to recall that if you got your license in a two control Ercoupe, you were not licensed to fly a three control without further training / sign off / etc.
KR> Pressure testing my wing tanks
On 31 January 2014 10:37, The Leonards wrote: > Gents > Use a balloon attached to one of the inlets/outlets of you tank. > I did the balloon thing on a tank I built recently. It was a riveted aluminum tank with lots of pro-seal. Put the balloon on the vent, put the air hose on the outlet, inflated the balloon, closed the outlet valve and left it. The balloon stayed up. After about 4 hours I decided that was good enough and let the air out. 2 days later I decided I wanted to make a dipstick for the tank so I set the tank at the orientation it would be in the parked aircraft and started filling it with water from a measuring jug. I got less than 4 litres in before water started leaking out. By the time the tank was full (about 32 litres) I had significant leaks from about a dozen spots. All this from a tank that 2 days earlier tested as airtight. Any suggestions? Cheers, Tony
KR> Pressure testing my wing tanks
Gents Use a balloon attached to one of the inlets/outlets of you tank. Temporarily seal the other inlets/outlets. Use one of other inlets/outlets to blow up the balloon so that it is about half inflated (on average 5 to 6inches diameter). Leave it sit for a couple of days. As the temperature in your workshop varies the balloon will either inflate more or deflate with expansion or contraction of the air with temp. What you are looking for is, after a couple of days the balloon is still inflated about the size you originally inflated it to. If it is like this then you probably have no leaks. This is standard practise on the Glasairs. Seems to work ok. The fun part is finding and fixing the leak if you have one. Another method is to fill the tank with a liquid (usually coloured water to almost full) then pressurise with air. Then look for leaks of coloured water. NOTE you only need a few pounds of pressure (3 to 4 at most). A bicycle pump is ok to pump up with, this way you are pumping it up slow so you will see any damage that is about to occur if you pressurise too much. Hope this helps. Cheers Peter -Original Message- From: KRnet [mailto:krnet-bounces at list.krnet.org] On Behalf Of Larry Flesner Sent: Friday, 31 January 2014 10:03 AM To: KRnet Subject: Re: KR> Pressure testing my wing tanks >Gas molecules are smaller than water molecules. Water testing for leaks >is inconclusive. >Gary ++ So true. Gas will leak it a big way through a hole that holds water. I use a funnel to filter fuel that passes gas at a high rate but not a single drop of water. When looking for a leak, use an 18 to 24 inch length of small diameter hose. Place one end in your ear and pass the other end over seams and areas of the tank you suspect may contain a leak. With 2 or 3 pounds of air pressure in the tank, a leak is hard to miss. It will put a very noticeable hiss in your ear. Larry Flesner ___ Search the KRnet Archives at http://tugantek.com/archmailv2-kr/search. To UNsubscribe from KRnet, send a message to KRnet-leave at list.krnet.org please see other KRnet info at http://www.krnet.org/info.html see http://list.krnet.org/mailman/listinfo/krnet_list.krnet.org to change options
KR> Pressure testing my wing tanks
On 31 January 2014 10:02, Larry Flesner wrote: > > Gas molecules are smaller than water molecules. > > ++ > > Not sure that's true. An oxygen atom with two attached hydrogen atoms (i.e. a water molecule) is not any bigger than two oxygen atoms joined together (the normal form of oxygen in the atmosphere) or two nitrogen atoms joined together (the normal form of nitrogen in the atmosphere) or a carbon with two oxygens (carbon dioxide). The reason gas leaks when water doesn't (and why fuel flows through a filter funnel when water doesn't) more likely has to do with the fact that water molecules tend to stick together due to intermolecular forces that are much stronger for water than they are for oxygen or nitrogen or carbon dioxide or fuel. TK > ___ > Search the KRnet Archives at http://tugantek.com/archmailv2-kr/search. > To UNsubscribe from KRnet, send a message to KRnet-leave at list.krnet.org > please see other KRnet info at http://www.krnet.org/info.html > see http://list.krnet.org/mailman/listinfo/krnet_list.krnet.org to change > options >
KR> Building the Wing Off the Plane?
I can't argue with the logic of building the wings separately and then attaching to the fuselage. 707s were done this way and they may still be building that way. On Jan 31, 2014 1:22 AM, "Mike T" wrote: > I'm still trying to decide whether to build a KR-2 or a Thatcher CX4, a > recent single-seat aluminum LSA design. These two designs aren't as far > apart as they seem, because a KR-2 can also be LSA compliant. It already > makes the LSA stall speed if you keep it light, and I could use a smaller > VW engine (or just adjust the throttle so the carb doesn't open all the > way) to get it down to the LSA top speed someday. I think the LSA law > would le me fly the plane fast for now, then slow it down to make it LSA > compliant if I ever get sick of getting medicals. By contrast, he CX4's top > speed is 135 mph and the VNE is 155, so it's not even as fast as the > fastest LSAs. > > But whatever plane I build, I want to build it in the living room of my > house. As I mentioned here before, I have woodworking and metalworking > machines in the basement, but that doesn't leave room for the plane down > there. Also I have a garage, but it has no heat and limited electricity, > and sometimes it's wet. So for much of the year I'd be unable to work > there, or I'd have to come home from work and fire up a heater for hours to > warm the garage. But with the plane in the living room, it would be warm, > dry, and staring me in the face whenever I came in the door, so I'd have an > incentive to keep working on it every day. > > But there's a problem doing this with a KR: The center spar is so long I'd > never be able to get it out again after the spar was installed, so I'd have > to move it to the garage after the boat stage. The spar is so long is to > allow for flaps and wing tanks, which I don't want, but trying to change > the design of the spar and wings would be way too complicated. > > So I was all set to give up on the KR2 (and I even bought plans for the > CX4) when I saw this article in the KR Newsletter of October, 1984 (#112, > p. 3). This is a guy who built his wings entirely off the plane. He was > doing it to make a better wing (and I think he's right). But doing this > would also solve my problem of getting the plane out the door when it's > done. And it would make it easier to build the wings exactly alike by > clamping the center spar to the worktable and building both wings at once. > (And of course you could flip the spar upside down easily, so you could > foam, glass, and finish both sides easily). Here's the guy's article, > between the dotted lines. > > --- > Here's a controversial one! I am building my wings *out* of the fuselage, > on a separate table, in a jig. I believe I will get a guaranteed true > wing, with the correct washout. This again steals from model-building > techniques. To be able to do this at all requires a way to remove the wing > from the fuselage, and to reassemble it to the fuselage after construction. > You can't obviously, *slide* the wing back into the fuselage spar slots. > > Here's what I'm doing. I completely installed the center spars in the > fuselage *except* that they *aren't glued.* Turning the fuselage onto its > top, I cut a slot through the bottom of the fuselage so the spars can be > lifted out, rather than slid out through the sides. When the wing is > finished, I'll just drop it back into the spar slot. I'll replace the > lower longerons, which had to be cut to replace the spar slot, by gluing a > new 5/8 square sub-longeron alongside the one I cut, with a healthy > overlap, scarf, and plenty of reinforcing glass cloth. > > Once the wing is separated in this manner, I can mount the spars on a work > table and be sure they are jigged perfectly into the correct dihedral, > washout, etc. > > This technique was worked out by my good friend Charlie North, who is a > licensed A & P, and who feels the end result will be a stronger, more > accurate finished product. I'll keep you posted on its success. > > Bill Thomas > 9 Pine Acres Drive > Canton, CT 06019 > -- > > Me again. So what do people think of this idea, and do you know if anyone > else has ever done it? Adding longeron and plywood reinforcements after > replacing the spar would add some weight to the plane, but I don't think it > would very much. > > Unfortunately Bill Thomas didn't keep his promise and never wrote anything > else about how this worked out. He later had an ad in the Newsletter for > some unused parts, and years later on KRnet he parted out a KR200 he said > he finished in 1989. He said this was because he was buying an RV and > didn't want the liability of selling the KR, but it sounded as though he > flew it a couple of hundred hours and there was nothing wrong with it. > > I'd be interested in hearing people's opinions about this idea, especially > the opinions of any A here. (Also, of
KR> Ercoup flying
Larry, I thought that was, "you can't fix stupid". Daniel R. Heath -?Lexington, SC -Original Message- Unfortunately, they were underpowered and people started flying them heavy, off short grass strips, in hot weather, and started hanging them on fence post. You can't always control stupid. :-) Larry Flesner
KR> Pressure testing my wing tanks
Vinyl ester resin is ethyl resistant. On Jan 31, 2014 2:36 AM, "Global Solutions" wrote: > On 2014-01-30 9:49 PM, Dan Prichard wrote: > >> Why vinyl ester resin? >> >> S >> > it doesn't react to gas like the other poly stuff does > Regards > Stan > > > ___ > Search the KRnet Archives at http://tugantek.com/archmailv2-kr/search. > To UNsubscribe from KRnet, send a message to KRnet-leave at list.krnet.org > please see other KRnet info at http://www.krnet.org/info.html > see http://list.krnet.org/mailman/listinfo/krnet_list.krnet.org to change > options >
KR> Pressure testing my wing tanks
On 2014-01-30 9:49 PM, Dan Prichard wrote: > Why vinyl ester resin? > > S it doesn't react to gas like the other poly stuff does Regards Stan
KR> Building the Wing Off the Plane?
I'm still trying to decide whether to build a KR-2 or a Thatcher CX4, a recent single-seat aluminum LSA design. These two designs aren't as far apart as they seem, because a KR-2 can also be LSA compliant. It already makes the LSA stall speed if you keep it light, and I could use a smaller VW engine (or just adjust the throttle so the carb doesn't open all the way) to get it down to the LSA top speed someday. I think the LSA law would le me fly the plane fast for now, then slow it down to make it LSA compliant if I ever get sick of getting medicals. By contrast, he CX4's top speed is 135 mph and the VNE is 155, so it's not even as fast as the fastest LSAs. But whatever plane I build, I want to build it in the living room of my house. As I mentioned here before, I have woodworking and metalworking machines in the basement, but that doesn't leave room for the plane down there. Also I have a garage, but it has no heat and limited electricity, and sometimes it's wet. So for much of the year I'd be unable to work there, or I'd have to come home from work and fire up a heater for hours to warm the garage. But with the plane in the living room, it would be warm, dry, and staring me in the face whenever I came in the door, so I'd have an incentive to keep working on it every day. But there's a problem doing this with a KR: The center spar is so long I'd never be able to get it out again after the spar was installed, so I'd have to move it to the garage after the boat stage. The spar is so long is to allow for flaps and wing tanks, which I don't want, but trying to change the design of the spar and wings would be way too complicated. So I was all set to give up on the KR2 (and I even bought plans for the CX4) when I saw this article in the KR Newsletter of October, 1984 (#112, p. 3). This is a guy who built his wings entirely off the plane. He was doing it to make a better wing (and I think he's right). But doing this would also solve my problem of getting the plane out the door when it's done. And it would make it easier to build the wings exactly alike by clamping the center spar to the worktable and building both wings at once. (And of course you could flip the spar upside down easily, so you could foam, glass, and finish both sides easily). Here's the guy's article, between the dotted lines. --- Here's a controversial one! I am building my wings *out* of the fuselage, on a separate table, in a jig. I believe I will get a guaranteed true wing, with the correct washout. This again steals from model-building techniques. To be able to do this at all requires a way to remove the wing from the fuselage, and to reassemble it to the fuselage after construction. You can't obviously, *slide* the wing back into the fuselage spar slots. Here's what I'm doing. I completely installed the center spars in the fuselage *except* that they *aren't glued.* Turning the fuselage onto its top, I cut a slot through the bottom of the fuselage so the spars can be lifted out, rather than slid out through the sides. When the wing is finished, I'll just drop it back into the spar slot. I'll replace the lower longerons, which had to be cut to replace the spar slot, by gluing a new 5/8 square sub-longeron alongside the one I cut, with a healthy overlap, scarf, and plenty of reinforcing glass cloth. Once the wing is separated in this manner, I can mount the spars on a work table and be sure they are jigged perfectly into the correct dihedral, washout, etc. This technique was worked out by my good friend Charlie North, who is a licensed A & P, and who feels the end result will be a stronger, more accurate finished product. I'll keep you posted on its success. Bill Thomas 9 Pine Acres Drive Canton, CT 06019 -- Me again. So what do people think of this idea, and do you know if anyone else has ever done it? Adding longeron and plywood reinforcements after replacing the spar would add some weight to the plane, but I don't think it would very much. Unfortunately Bill Thomas didn't keep his promise and never wrote anything else about how this worked out. He later had an ad in the Newsletter for some unused parts, and years later on KRnet he parted out a KR200 he said he finished in 1989. He said this was because he was buying an RV and didn't want the liability of selling the KR, but it sounded as though he flew it a couple of hundred hours and there was nothing wrong with it. I'd be interested in hearing people's opinions about this idea, especially the opinions of any A here. (Also, of course, if Bill Thomas or the A who designed this setup 30 years ago are here, I'd like to hear from you, but that seems pretty unlikely at this point). Mike Taglieri
KR> N6338Z update
On 1/30/2014 1:38 PM, Roger Bulla wrote: > It has been a while since I posted a update on the KR. It is now flying! This > is a plans built KR-2 with a VW 2180. Took its first flight in late October > 2013. No surprises. I have the original Rand fixed gear that looks very close > to the Grove gear. Visibility over the nose on the ground in nonexistent, but > ground handling is good as well as handling in flight. I biased the cg toward > the front to keep it stable and plus it is easy to correct a nose heavy > aircraft. My cg is around 1.5 inches in front of the center of lift with me > in the plane and low fuel. Of course the pilot has shed around 30 lbs since > then, so it has move a little further forward. > > The aircraft seems straight, with the elevator trimmed, if I let go of the > controls I get a very gentile turn to the right. When the power is pulled > back and the stock flaps are extended to descend, the nose gets very heavy, > but the plane is stable and easy to land. The only real problem I have is > getting the Revflow carburetor to work properly. It keeps trying to kill me > or at least keep my heart rate up. I have talked to Joe Horvath he is going > grind a needle with a different taper on it to see can get to settle in. I > have a Tillotson HD that I am about ready to try. I also still have the > Zenith I used on my old KR that worked very well for the twenty years I flew > it. > > I hope to get some wheel pants and a coarser prop on the plane soon and get > it ready to make the gathering this year. I currently have an old Sterba > Prop, (54x46) that I have had as a spare for many years. It came with an > engine I purchased in 1987 and does a great job flying around the valley here > in Grand Junction, but the engine needs more pitch on the prop. With the Rand > fixed gear I have plenty of ground clearance for a longer prop. With the 54 > inch prop, and in a level attitude I have 14 inches of ground clearance but I > am not sure what combination of pitch and length will work best. > > Its Great to be back in the air. These little planes will keep you grinning. > > > Roger Bulla > rbulla2 at wic.net > > > ___ > Search the KRnet Archives at http://tugantek.com/archmailv2-kr/search. > To UNsubscribe from KRnet, send a message to KRnet-leave at list.krnet.org > please see other KRnet info at http://www.krnet.org/info.html > see http://list.krnet.org/mailman/listinfo/krnet_list.krnet.org to change > options > > Roger, You can try a different needle if you want, with the RevFlow carb, but ultimately you will probably find as I did on my 1835cc VW on my KR-1 can only best be explained if you have gone thru the same trial and error as I did and others in trying to make it work. I had a Tilitson float bowl carb originally, but when the accelerator pump became worn out and I could not find parts to fix it, then I went to a AeroCarb, couldnt make that work,ended up with the RevFlow and eventually made it work,,,But just ok,,,I have never been happy with the performance. I can save you some frustration with a phone call and a possible solution to the way it can be made to run better if you care to give me a call this weekend and I will explain what you will eventually find out yourself by trial and error. John Edwards in Graham WA 253-208-2587 PS, If you have a good Tilitson carb use it! and sell you RevFlo to someone else...
