From: krnet-bounces@mylist.net To: John Bouyea Subject: KRnet Digest, Vol 347, Issue 379 Date: 9/25/2005 9:00:22 PM Send KRnet mailing list submissions to krnet@mylist.net To subscribe or unsubscribe via the World Wide Web, visit http://mylist.net/listinfo/krnet or, via email, send a message with subject or body 'help' to krnet-request@mylist.net You can reach the person managing the list at krnet-owner@mylist.net When replying, please edit your Subject line so it is more specific than "Re: Contents of KRnet digest..." Today's Topics: 1. Re: Jeff Scott's Modifications - Early Flight test results (jscott.pilot@juno.com) 2. Re: Engine Torque (Scott William) 3. Re: Subaru Vs others (Phil Matheson) 4. Re: Subaru Vs others (Scott William) 5. Re: Hardware (Ameet Savant) 6. Bubbles (Mark Jones) 7. Re: Bubbles (Ameet Savant) 8. Re: Bubbles (Mark Jones) 9. Jeff Scotts Report (jeroffey) 10. Re: Bubbles (Orma) 11. Re: Hardware (Scott William) 12. Re: Engine Torque (IFLYKRS@aol.com) 13. RE: Jeff Scott's Modifications - Early Flight test results (Brian Kraut) 14. Re: Bubbles (larry severson) 15. copper state (Lee Van Dyke) 16. Re: Bubbles (Lee Van Dyke) ---------------------------------------------------------------------- Message: 1 Date: Sat, 24 Sep 2005 22:16:04 -0600 From: jscott.pilot@juno.com Subject: Re: KR> Jeff Scott's Modifications - Early Flight test results To: krnet@mylist.net Message-ID: <20050924.221605.2716.1.jscott.pilot@juno.com> Content-Type: text/plain; charset=us-ascii Here's my analysis of the changes I have implemented on my KR over the last 4 months following the FAA's mandated 5 hours of test flying. Clearly I'm still a long ways from being done testing, and I'm not done modifying, although I am a bit burned out on it for now. The modifications to the horozontal stab and elevator turned out to have very positive results. The challenge is how to best quantify the results into something that makes sense. I'll start with the new horizontal stab and elevator. Incidence: In building the new stab, I attempted to correct the incidence. I need some in flight photos to know how close I got it, but from the test flight results, I would say it is very close, although a touch more nose down would probably have resolved my trim problems. More on that later. Stability: The larger 8 foot span horizontal stab is absolutely fabulous. The best example I can give is a comparison that was easy to make. As I was flying home from the SWRFI in May, after about 3 hours in the seat my butt was numb, so I let lose of the stick and used my hands to scootch up in the seat a bit. That movement with me at 270# caused a quick 1/2G negative on the G-meter before all the stuff from my right seat and lap came raining back down on me from the canopy. I have done the same thing several times in the last few hours of test flying. The plane simply doesn't change in pitch in any noticeable way. The stability hands off is abloslutely rock solid. Feel: There have been comments in the past that by building a larger stab to change the stability, the plane would lose it's sporty feel. I can easily put that rumor to rest. The elevator is every bit as quick as it ever was, although it does have a bit more aerodynamic load on it, so gives a bit more feedback through the stick. Credit Mark Langford for the stab/elevator design and for posting it to his web page. My recommendation is to use it. It works... very well. I think I can truthfully say that mine is the only KR to have flown with both tails and I think my preference is clear. Wing Root Fairings: The wing root fairings were created for two purposes. #1 was to reduce drag by cleaning up the air flow at the wing root junction with the fuselage. #2 was to hide the actuator linkage to the new flaps. Despite having added a significant amount of weight to the plane with all the mods, it has picked up some speed as well. Not a lot. The small amount of testing I have done so far has shown a 4 - 7 mph increase in indicated airspeed at 9000'. Density altitude was roughly 11,000' during testing. Full throttle straight and level at 9000' used to yield a top indicated airspeed of 143 mph. This week I have seen it top out from 147 - 150 mph IAS at 9000' in various configurations. Flaps: The flaps are an absolutely fabulous addition to the plane. My wing stub flaps are 11 1/2 x 25" per side and deploy to 37 degrees. All I can say is WOW! I can turn final at 160 indicated, pull the nose up, reduce power and drop the flaps and this plane will drop out of the sky like a Cessna. No more planning the approach from 10 miles out to try to get down. I can either reduce flaps or add power to have complete control of the descent. No more gliding half the runway in ground effect while the plane slowly bleeds off speed. With this much deployable drag, I can drop the plane on a spot. A performance requirement that I placed on the flaps was that the plane had to be able to climb with full flaps. I took off with the Density Altitude at 9300' and sluggishly climbed from 7200' (airport altitude) through 8000'. Rudder: In my opinion, the larger rudder has also enhanced the controlability of the plane. Between the larger rudder and the drag generated by the flaps, crosswind landings have changed from a real wrestling match to a non-event. Elevator Trim: I designed my own elevator trim control using biasing springs and the original MAC trim servo out of the old tail. This piece is unique to the geometry of my elevator control system. (see the last two entries under http://www.vla.com/jscott/kr/index.htm) I have spent the bulk of my test flying time tuning the trim. I do have it to a functional level, but not optimal. The issue seems to be that at speed the aerodynamic loads on the elevator is sufficient enough that the biasing spring is unable to keep the nose down past roughly 145 mph indicated. This works OK for cruise at 9000', but may not work so well when I get the plane to a low altitude (which is rare for me!). I'm going to be tuning on the trim control for a while yet. The challenge is to get enough spring pressure to trim the elevator while keeping the springs light enough to not ruin the light feel of the plane. Since the required test time is already flown off the plane, in all likelyhood I will have it at Copperstate again this year despite it's unfinished state. Jeff Scott N1213W ------------------------------ Message: 2 Date: Sat, 24 Sep 2005 22:33:42 -0700 (PDT) From: Scott William Subject: Re: KR> Engine Torque To: brokerpilot96ta@earthlink.net, KRnet Message-ID: <20050925053342.16103.qmail@web31514.mail.mud.yahoo.com> Content-Type: text/plain; charset=iso-8859-1 I understand that Colin....you missed my point. Read the guy's ad on the website. Let me quote again: "This engine based on the type 1 VW engine produces an incredible 200ft lb + Torque and with 85 Horsepower driven through our Helical Gear Drive...." This guy claims the motor makes the power AND THEN it's fed through the gear drive, or at least that's the way the reader can be lead to believe. One thing I have learned in the engine building business is that guys that can do, do. Guys that can't, claim to perform miracles. Remember, this is the same outfit that claims to be able to "solve" all the crankshaft woes of the corvair engine. That's funny, with the exception of a few, I didn't know they had any woes to solve. If his gear drive is a 1.6, since he claims prop speed of 2750rpm, that means he is producing his power at 4400 engine rpm. At a 1.6 reduction, with his claimed 200 ft/lbs of torque, he would have to be producing 125ft/lbs of torque at 4400rpm, which equates to 104 hp at 4400 rpm. By his own admission in the ad, he's only producing 85hp. Bottom line is this: His math don't add up. And for that reason, in my mind, he can't be trusted and I wouldn't buy his products. Nothing personal, Colin. But I hope you can understand my point of view. --- Colin Rainey wrote: > Scott > One correction you have to make to your numbers is > the fact that you are figuring everything direct > drive, not taking into account torque multiplication > through the gear drive. Torque ends up multiplied > by the factor of the reduction. This is how turbo > prop engines make such big numbers with such small > power plants. They are set up on something on the > order of like 16 to 1 or 20 to 1. 50 foot pounds of > torque at the shaft is multiplied by the gear > reduction by the percentage reduction, ie: 16 x 50 = > 900 foot pounds at the prop. This is like the PT6 > Pratt & Whitney engine, that can be turned down from > its 1500 hp max, to around 400-600 for other > applications ( Saratoga hop up conversions). So a > VW making 60 hp and 85 foot pounds of torque through > a 1.6 to 1 reduction drive would make 60% more power > or 136 foot pounds of torque at the prop. Just food > for thought. More info in Richard Finch's book on > auto engine conversions.... > > > Colin Rainey > brokerpilot96ta@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-leave@mylist.net > please see other KRnet info at > http://www.krnet.org/info.html > __________________________________ Yahoo! Mail - PC Magazine Editors' Choice 2005 http://mail.yahoo.com ------------------------------ Message: 3 Date: Sun, 25 Sep 2005 20:07:28 +1000 From: "Phil Matheson" Subject: Re: KR> Subaru Vs others To: "KRnet" Message-ID: <004601c5c1b9$5f157740$60a8443d@Office> Content-Type: text/plain; format=flowed; charset="iso-8859-1"; reply-type=original Scott William wrote: Ok, so let me see if I am not reading this with blurry eyes.... Do you really believe the claims of these guys? ------------------------------------------------------------------- Scott. Is Scott really a mathematician or one that is trying to pull the wool over the eyes of others and still has blurry eyes from the night before. Scott forgets that there is a gear drive involved and evidently knows very little about gears and torque. A std 1600 vw and most type 4 engines produce about 130 ft lb of torque at 3500 rpm ...........check the VW book Scotty. We didn't say that the engine produces 200 ft lb of torque ............ The engine produces around 130 ft lb of torque and also around 80/85 hp. at 4,200 rpm The gear drive multiplies the torque by the gear ratio which is 1.6 to 1 which equates to over 200 ft lb of torque at the prop. The reality is by gearing we increase the available torque and provide an rpm more suited to an efficient prop diameter. The gear drive unloads the engine, allows a more efficient cruise rpm around 3200 to 3300 and that is BELOW normal highway cruising on a VW engine. If you had divided the 200ft lbs of torque you have found 208 Div by 1.6 = 130ft lbs at the crankshaft Of coarse you knew that Scott. Ron Slender Managing Director VW Engine Centre Pty Ltd Phil Matheson mathesonp@dodo.com.au VH-PKR ( Phil's KR) 61 3 58833588 Australia.( Down Under) See My KR2 Building Web Page at: http://mywebpage.netscape.com/flyingkrphil/VHPKR.html See our VW Engines and Home built web page at http://www.vw-engines.com/ www.homebuilt-aviation.com/ http://corvair.vw-engines.com/ ------------------------------ Message: 4 Date: Sun, 25 Sep 2005 05:57:06 -0700 (PDT) From: Scott William Subject: Re: KR> Subaru Vs others To: KRnet Message-ID: <20050925125707.78148.qmail@web31503.mail.mud.yahoo.com> Content-Type: text/plain; charset=iso-8859-1 --- Phil Matheson wrote: > Scott forgets that there is a gear drive involved > and evidently knows very > little about gears and torque. WHy don't you go read my other reply before you hit the send button? I was referring to the appearance of misleading wording on the website. But since you brought up the subject of math, let's talk about your math vs. what the website claims, shall we? Now, I'm not a mathmetician, nor did I stay at a Holiday Inn last night, but you stated..... > A std 1600 vw and most type 4 engines produce about > 130 ft lb of torque at > 3500 rpm ...........check the VW book Scotty. I don't have to look at a book. I know this from experience. I also know that if your measuring peak HP at 4400 rpm, you must do so with the torque produced at that rpm, not the peak torque produced at a lower rpm. > We didn't say that the engine produces 200 ft lb of > torque ............ To quote the raven, "Nevermore". But, to quote your website, "This engine based on the type 1 VW engine produces an incredible 200ft lb + Torque and with 85 Horsepower...." Of course, then you continue to say, "...driven through our Helical Gear Drive will surely give your Aircraft what it needs up front". It appears to be a play on words. Maybe it was just an honest error. I'll give the benefit of the doubt, because the English language is a funny thing in that sometimes we don't write what we exactly meant. SOmetimes we don't say what we meant to say. > The engine produces around 130 ft lb of torque and > also around 80/85 hp. at > 4,200 rpm > The gear drive multiplies the torque by the gear > ratio which is 1.6 to 1 > which equates to over 200 ft lb of torque at the > prop. So, does it produce 130ft/lb at 4200 rpm, or does it produce 85hp at 4200 rpm? Because, it isn't doing both. By using the standard equation for horse power....now remember, I didn't stay at a Holiday Inn last night....and using your numbers above that you tried to explain to me.... with Horse Power = torque*RPM /5252 (the standard HP calculation for rotating objects), that means that, by your words above, 103 = 130*4200/5252. That's 103 horsepower. So, to go back to your claim that they produce peak torque at 3500rpm, and let's plug it in, shall we? 86HP= 130*3500/5252 So if your motor produces peak torque at 3500 rpm, then it equates to 200 ft/lbs of torque at the prop, with a 1.6 reduction drive, correct? Ok, so then you say this: >If you had divided the 200ft lbs of torque you have > found 208 Div by 1.6 = > 130ft lbs at the crankshaft Ok, so 208 ft/lbs of torque, which you say occurs at 3500rpm, means that at peak torque, you are turning the prop at 2187 rpm. Here, let me quote your website again: "2750 prop rpm". 2750*1.6 = 4400. So, does your motor produce peak torque at 3500rpm or 4400rpm? If it's 3500 rpm as you say, then your gear drive isn't producing 200 ft/lbs of torque at a prop speed of 2750, now is it? How much does it produce at prop speed? Here, let me try some math again. Since peak HP is measured at a point of the power curve in which the increase of RPM crosses the decrease in torque to produce a maximum number, in the case of the VW engine, depending on the cam, (in the case of your engine), peak HP would be produced at 4400rpm. So, in the case of what you have told me, that being your motor produces "also around 80/85 hp", then 85 = 101*4400/5252. Your motor is producing 101ft/lbs of torque at 4400 rpm. So, if I gear reduce that....which would be hard, because you said that I, "evidently knows very little about gears and torque"........anyway, that means that 4400rpm /1.6 = 2750, and 101ft/lbs *1.6 = 161ft/lbs at prop speed. So, do I turn my prop at 2187rpm to make most effective use of your torque number, or do I turn it faster and get less power? My point is this: WHat you advertise and what you deliver leave the appearance of being two different things. Here, let me quote the rest of the email you have here: > The reality is by gearing we increase the available > torque and provide an > rpm > more suited to an efficient prop diameter. > The gear drive unloads the engine, allows a more > efficient cruise rpm > around 3200 to 3300 and that is BELOW normal highway > cruising on a VW > engine. > WHat you say is true. You do increase available torque. But, you should be fair in your statements of how much and at what level. People may buy hype, but airplanes don't fly on it. Scott __________________________________________________ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com ------------------------------ Message: 5 Date: Sun, 25 Sep 2005 07:03:30 -0700 (PDT) From: Ameet Savant Subject: Re: KR> Hardware To: KRnet Message-ID: <20050925140330.7789.qmail@web60814.mail.yahoo.com> Content-Type: text/plain; charset=iso-8859-1 Scott, You might want to read the corrosion and titanium embrittlement articles on this website http://www.eaa1000.av.org/technicl/corrosion/corridx.htm I think the ones of interest for you would be the "Galvanic Table" and the "Don't mix Ti and Cd" articles. Besides price, I guess corrosion would be a consideration as someone else rightly pointed out earlier. Regards, Ameet --- Scott William wrote: > Has anyone here used titanium bolts in > thier > airframe? Other than FAA examiner scrutiny (such as > with the WAF) is there any reason not to use them > besides price? > > > Scott > __________________________________________________ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com ------------------------------ Message: 6 Date: Sun, 25 Sep 2005 09:21:29 -0500 From: "Mark Jones" Subject: KR> Bubbles To: "KR Net" Message-ID: <002201c5c1dc$6c598860$6401a8c0@wi.rr.com> Content-Type: text/plain; charset="iso-8859-1" Net Heads, I have acquired a few bubbles under the fiberglass skin on my stub wings.Apparently these are some sort of gas bubble which has caused the phenomenon. The largest one is about 1 1/2 inch wide and 2 inches long. These bubbles were fairly hard till I drilled a pin size hole in them to relieve the pressure. Now, I can push the skin down to the foam easily. I was hoping by drilling the pin holes the skin would eventually lay flat however this has not happened yet. Now I am thinking heating them with a heat gun might do the trick. Have any of you experienced this and how did you rectify the problem? Mark Jones (N886MJ) Wales, WI USA E-mail me at flykr2s@wi.rr.com Visit my KR-2S CorvAIRCRAFT web site at http://mywebpage.netscape.com/n886mj ------------------------------ Message: 7 Date: Sun, 25 Sep 2005 07:22:35 -0700 (PDT) From: Ameet Savant Subject: Re: KR> Bubbles To: KRnet Message-ID: <20050925142235.68381.qmail@web60815.mail.yahoo.com> Content-Type: text/plain; charset=iso-8859-1 Mark, Just a suggestion... Would it be better to cut the bubble off, grade it's sides all around and do a fresh small layup on it. Just like you would have had to do it you were repairing a puncture? Regards, Ameet --- Mark Jones wrote: > Net Heads, > I have acquired a few bubbles under the fiberglass > skin on my stub > Have any of you > experienced this and how did > you rectify the problem? > > Mark Jones (N886MJ) > Wales, WI USA > E-mail me at flykr2s@wi.rr.com > Visit my KR-2S CorvAIRCRAFT web site at > http://mywebpage.netscape.com/n886mj > > > > > _______________________________________ > Search the KRnet Archives at > http://www.maddyhome.com/krsrch/index.jsp > to UNsubscribe from KRnet, send a message to > KRnet-leave@mylist.net > please see other KRnet info at > http://www.krnet.org/info.html > __________________________________ Yahoo! Mail - PC Magazine Editors' Choice 2005 http://mail.yahoo.com ------------------------------ Message: 8 Date: Sun, 25 Sep 2005 09:36:10 -0500 From: "Mark Jones" Subject: Re: KR> Bubbles To: "KRnet" Message-ID: <002e01c5c1de$79238a80$6401a8c0@wi.rr.com> Content-Type: text/plain; charset="iso-8859-1" That is one way to do it. Mark Jones (N886MJ) Wales, WI USA E-mail me at flykr2s@wi.rr.com Visit my KR-2S CorvAIRCRAFT web site at http://mywebpage.netscape.com/n886mj ----- Original Message ----- From: "Ameet Savant" To: "KRnet" Sent: Sunday, September 25, 2005 9:22 AM Subject: Re: KR> Bubbles > Mark, > > Just a suggestion... Would it be better to cut the > bubble off, grade it's sides all around and do a fresh > small layup on it. Just like you would have had to do > it you were repairing a puncture? > > Regards, > Ameet > > > --- Mark Jones wrote: > > > Net Heads, > > I have acquired a few bubbles under the fiberglass > > skin on my stub > > Have any of you > > experienced this and how did > > you rectify the problem? > > > > Mark Jones (N886MJ) > > Wales, WI USA > > E-mail me at flykr2s@wi.rr.com > > Visit my KR-2S CorvAIRCRAFT web site at > > http://mywebpage.netscape.com/n886mj > > > > > > > > > > _______________________________________ > > Search the KRnet Archives at > > http://www.maddyhome.com/krsrch/index.jsp > > to UNsubscribe from KRnet, send a message to > > KRnet-leave@mylist.net > > please see other KRnet info at > > http://www.krnet.org/info.html > > > > > > > __________________________________ > Yahoo! Mail - PC Magazine Editors' Choice 2005 > http://mail.yahoo.com > > _______________________________________ > Search the KRnet Archives at http://www.maddyhome.com/krsrch/index.jsp > to UNsubscribe from KRnet, send a message to KRnet-leave@mylist.net > please see other KRnet info at http://www.krnet.org/info.html > ------------------------------ Message: 9 Date: Sun, 25 Sep 2005 10:32:43 -0400 (GMT-04:00) From: jeroffey Subject: KR> Jeff Scotts Report To: krnet@mylist.net Message-ID: <31840183.1127658764183.JavaMail.root@elwamui-chisos.atl.sa.earthlink.net> Content-Type: text/plain; charset=us-ascii I have been on this list for more years than I care to admit to, but the information provided by Jeff Scott in his analysis of his modifications has to be one of the most valuable pieces of information ever presented to date. This unique opportunity to witness the comparison of the old and new elevators takes the question of building to plans or using the elevator plan offered by Mark Langford a moot point. The results presented by Jeff differ from Marks performance reports by the value of having flown both on the same plane. This is the very essence of the word "EXPERIMENTAL". Thank You Jeff Scott !!!! P.S. I won't make Copperstate this year. Another wedding that week end. Eight this year, two in AZ, two in Canada, the others local and in the Detroit area. We get around. John Roffey KR2S Someday jeroffey@tir.com ------------------------------ Message: 10 Date: Sun, 25 Sep 2005 10:33:39 -0400 From: "Orma" Subject: Re: KR> Bubbles To: "KRnet" Message-ID: <004901c5c1de$20ac7240$0302a8c0@ROBBINS1> Content-Type: text/plain; format=flowed; charset="iso-8859-1"; reply-type=original Bubbles are sometimes formed by moisture under the skin that cooks and the gas expands stretching the plastic skin. Another cause is the use of spray foam, which sits un-cured encapsulated by cured foam and glass, until one day it gets enough heat to cure and at that point it expands, creating a bubble. Depending on how your bubble was formed, you can do as Ameet suggested or you can cut the bubble and inject epoxy under the bubble, cover with waxed paper and add weight till cured. If the bubble was caused by spray foam, you might have to use a heat lamp to look for other uncured spots Orma Southfield, MI KR-2 N110LR 1984 See Tweety at http://www.kr-2.aviation-mechanics.com See other KR spces at www.kr-2.aviation-mechanics.com/krinfo.htm ------------------------------ Message: 11 Date: Sun, 25 Sep 2005 08:06:01 -0700 (PDT) From: Scott William Subject: Re: KR> Hardware To: KRnet Message-ID: <20050925150602.150.qmail@web31503.mail.mud.yahoo.com> Content-Type: text/plain; charset=iso-8859-1 I was thinking of issues in terms of thread galling, "cold welding" of two titanium parts. I never thought of it from a corrosion aspect. Well, I guess if I wish to use titanium bolts, I'll have to construct titanium parts to go along with them. ;-) Thanks for the insight. That's why I like you guys.... Scott --- Ameet Savant wrote: > Scott, > > You might want to read the corrosion and titanium > embrittlement articles on this website > > http://www.eaa1000.av.org/technicl/corrosion/corridx.htm > > I think the ones of interest for you would be the > "Galvanic Table" and the "Don't mix Ti and Cd" > articles. > > Besides price, I guess corrosion would be a > consideration as someone else rightly pointed out > earlier. > > Regards, > Ameet > > --- Scott William wrote: > > > Has anyone here used titanium bolts in > > thier > > airframe? Other than FAA examiner scrutiny (such > as > > with the WAF) is there any reason not to use them > > besides price? > > > > > > Scott > > > > > __________________________________________________ > Do You Yahoo!? > Tired of spam? Yahoo! Mail has the best spam > protection around > http://mail.yahoo.com > > _______________________________________ > Search the KRnet Archives at > http://www.maddyhome.com/krsrch/index.jsp > to UNsubscribe from KRnet, send a message to > KRnet-leave@mylist.net > please see other KRnet info at > http://www.krnet.org/info.html > __________________________________________________ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com ------------------------------ Message: 12 Date: Sun, 25 Sep 2005 11:20:05 EDT From: IFLYKRS@aol.com Subject: Re: KR> Engine Torque To: krnet@mylist.net Message-ID: <126.662569a6.30681a25@aol.com> Content-Type: text/plain; charset="US-ASCII" As far a HP and torque on the Corvair engine check out the info from the dyno tests that WW performed at FLYCORVAIR.com. Here is actual HP performance figures on an engine (0-200) as it came off the airplane and the Corvair 110 as it came off the airplane. These are HP and torque at the prop and with accessories. It shows the difference to HP derived from computation and actual. The claim on my Revemaster 2100 was 80 HP but I never really believed it. I think that actual it was closer to 65 or 70. Torque is a big factor. The Corvair has more torque on 5 cylinders than my VW 2100 turbo ever had. Just food for thought. Bill ------------------------------ Message: 13 Date: Sun, 25 Sep 2005 11:37:56 -0400 From: "Brian Kraut" Subject: RE: KR> Jeff Scott's Modifications - Early Flight test results To: "KRnet" Message-ID: Content-Type: text/plain; charset="US-ASCII" Great information. Thanks for the feedback and keep it coming. Brian Kraut Engineering Alternatives, Inc. www.engalt.com -----Original Message----- From: krnet-bounces@mylist.net [mailto:krnet-bounces@mylist.net]On Behalf Of jscott.pilot@juno.com Sent: Sunday, September 25, 2005 12:16 AM To: krnet@mylist.net Subject: Re: KR> Jeff Scott's Modifications - Early Flight test results Here's my analysis of the changes I have implemented on my KR over the last 4 months following the FAA's mandated 5 hours of test flying. Clearly I'm still a long ways from being done testing, and I'm not done modifying, although I am a bit burned out on it for now. The modifications to the horozontal stab and elevator turned out to have very positive results. The challenge is how to best quantify the results into something that makes sense. I'll start with the new horizontal stab and elevator. Incidence: In building the new stab, I attempted to correct the incidence. I need some in flight photos to know how close I got it, but from the test flight results, I would say it is very close, although a touch more nose down would probably have resolved my trim problems. More on that later. Stability: The larger 8 foot span horizontal stab is absolutely fabulous. The best example I can give is a comparison that was easy to make. As I was flying home from the SWRFI in May, after about 3 hours in the seat my butt was numb, so I let lose of the stick and used my hands to scootch up in the seat a bit. That movement with me at 270# caused a quick 1/2G negative on the G-meter before all the stuff from my right seat and lap came raining back down on me from the canopy. I have done the same thing several times in the last few hours of test flying. The plane simply doesn't change in pitch in any noticeable way. The stability hands off is abloslutely rock solid. Feel: There have been comments in the past that by building a larger stab to change the stability, the plane would lose it's sporty feel. I can easily put that rumor to rest. The elevator is every bit as quick as it ever was, although it does have a bit more aerodynamic load on it, so gives a bit more feedback through the stick. Credit Mark Langford for the stab/elevator design and for posting it to his web page. My recommendation is to use it. It works... very well. I think I can truthfully say that mine is the only KR to have flown with both tails and I think my preference is clear. Wing Root Fairings: The wing root fairings were created for two purposes. #1 was to reduce drag by cleaning up the air flow at the wing root junction with the fuselage. #2 was to hide the actuator linkage to the new flaps. Despite having added a significant amount of weight to the plane with all the mods, it has picked up some speed as well. Not a lot. The small amount of testing I have done so far has shown a 4 - 7 mph increase in indicated airspeed at 9000'. Density altitude was roughly 11,000' during testing. Full throttle straight and level at 9000' used to yield a top indicated airspeed of 143 mph. This week I have seen it top out from 147 - 150 mph IAS at 9000' in various configurations. Flaps: The flaps are an absolutely fabulous addition to the plane. My wing stub flaps are 11 1/2 x 25" per side and deploy to 37 degrees. All I can say is WOW! I can turn final at 160 indicated, pull the nose up, reduce power and drop the flaps and this plane will drop out of the sky like a Cessna. No more planning the approach from 10 miles out to try to get down. I can either reduce flaps or add power to have complete control of the descent. No more gliding half the runway in ground effect while the plane slowly bleeds off speed. With this much deployable drag, I can drop the plane on a spot. A performance requirement that I placed on the flaps was that the plane had to be able to climb with full flaps. I took off with the Density Altitude at 9300' and sluggishly climbed from 7200' (airport altitude) through 8000'. Rudder: In my opinion, the larger rudder has also enhanced the controlability of the plane. Between the larger rudder and the drag generated by the flaps, crosswind landings have changed from a real wrestling match to a non-event. Elevator Trim: I designed my own elevator trim control using biasing springs and the original MAC trim servo out of the old tail. This piece is unique to the geometry of my elevator control system. (see the last two entries under http://www.vla.com/jscott/kr/index.htm) I have spent the bulk of my test flying time tuning the trim. I do have it to a functional level, but not optimal. The issue seems to be that at speed the aerodynamic loads on the elevator is sufficient enough that the biasing spring is unable to keep the nose down past roughly 145 mph indicated. This works OK for cruise at 9000', but may not work so well when I get the plane to a low altitude (which is rare for me!). I'm going to be tuning on the trim control for a while yet. The challenge is to get enough spring pressure to trim the elevator while keeping the springs light enough to not ruin the light feel of the plane. Since the required test time is already flown off the plane, in all likelyhood I will have it at Copperstate again this year despite it's unfinished state. Jeff Scott N1213W _______________________________________ Search the KRnet Archives at http://www.maddyhome.com/krsrch/index.jsp to UNsubscribe from KRnet, send a message to KRnet-leave@mylist.net please see other KRnet info at http://www.krnet.org/info.html ------------------------------ Message: 14 Date: Sun, 25 Sep 2005 15:31:03 -0700 From: larry severson Subject: Re: KR> Bubbles To: KRnet Message-ID: <5.2.1.1.0.20050925152603.022bfeb0@pop-server.socal.rr.com> Content-Type: text/plain; charset="us-ascii"; format=flowed >I have acquired a few bubbles under the fiberglass skin on my stub >wings.Apparently these are some sort of gas bubble which has caused the >phenomenon. The largest one is about 1 1/2 inch wide and 2 inches long. Drill a tiny hole at each end of the bubble, mix some wet micro, insert it in one of the holes with a hypodermic needle tube, and cover the resulting patch with weighted down plastic. When the micro cures, the bubble will be gone. Larry Severson Fountain Valley, CA 92708 (714) 968-9852 larry2@socal.rr.com ------------------------------ Message: 15 Date: Sun, 25 Sep 2005 19:27:56 -0700 From: "Lee Van Dyke" Subject: KR> copper state To: "KRnet" Message-ID: <007501c5c241$e7b97140$6601a8c0@SNAKEBITE> Content-Type: text/plain; charset="iso-8859-1" Netters, Copperstate is at Casa Grande Airport this year, not the dust pit of last year. I will have my KR2 there this year. How many other people plan on attending Copperstate????? Lee Van Dyke Mesa AZ Lee@vandyke5.com ------------------------------ Message: 16 Date: Sun, 25 Sep 2005 19:31:18 -0700 From: "Lee Van Dyke" Subject: Re: KR> Bubbles To: "KRnet" Message-ID: <008a01c5c242$6252a2a0$6601a8c0@SNAKEBITE> Content-Type: text/plain; charset="iso-8859-1" Mark Don't heat them you will get a bigger bubble.... I speak from experience. Sand it down and layup a new layer or 2 depending how deep you have to sand.... Lee ----- Original Message ----- From: "Mark Jones" To: "KR Net" Sent: Sunday, September 25, 2005 7:21 AM Subject: KR> Bubbles > Net Heads, > I have acquired a few bubbles under the fiberglass skin on my stub > wings.Apparently these are some sort of gas bubble which has caused the > phenomenon. The largest one is about 1 1/2 inch wide and 2 inches long. > These bubbles were fairly hard till I drilled a pin size hole in them to > relieve the pressure. Now, I can push the skin down to the foam easily. I > was hoping by drilling the pin holes the skin would eventually lay flat > however this has not happened yet. Now I am thinking heating them with a > heat gun might do the trick. Have any of you experienced this and how did > you rectify the problem? > > Mark Jones (N886MJ) > Wales, WI USA > E-mail me at flykr2s@wi.rr.com > Visit my KR-2S CorvAIRCRAFT web site at > http://mywebpage.netscape.com/n886mj > > > > > _______________________________________ > Search the KRnet Archives at http://www.maddyhome.com/krsrch/index.jsp > to UNsubscribe from KRnet, send a message to KRnet-leave@mylist.net > please see other KRnet info at http://www.krnet.org/info.html > > > ------------------------------ _______________________________________________ See KRnet list details at http://www.krnet.org/instructions.html End of KRnet Digest, Vol 347, Issue 379 *************************************** ================================== ABC Amber Outlook Converter v4.20 Trial version ==================================