From: krnet-bounces+johnbou=speakeasy.net@mylist.net To: John Bouyea Subject: KRnet Digest, Vol 346, Issue 60 Date: 8/5/2004 8:59:45 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: Flexplate (jscott.pilot@juno.com) 2. tortional loads +early friday (Dene Collett (SA)) 3. Re: @WL KR> tortional loads +early friday (gleone) 4. retract gears/was something else (Oscar Zuniga) 5. bottom skin will no linger be continuous between the spars (Dan Heath) 6. Re: tortional loads & cereal box experiments! (Scott Cable) 7. Re: @WL KR> tortional loads +early friday (Ron Eason) ---------------------------------------------------------------------- Message: 1 Date: Thu, 5 Aug 2004 17:43:50 GMT From: "jscott.pilot@juno.com" Subject: RE: KR> Flexplate To: krnet@mylist.net Message-ID: <20040805.104450.2741.238277@webmail17.lax.untd.com> Content-Type: text/plain I have determined that there is some minute induced oscillation at 2500 to 2550 rpm. -------------------- While it may not necessarily be damaging, what you have found is a resonate frequency between the flex plate and the engine RPM. It is possible that it could eventually cause cracking of the flex plate. Whether that would take 10 hours or 10,000,000 hours to crack is beyond the scope of any advice I could give. Since the "flexplate" is designed to flex and it would be quite rare to run a flying 'vair at 2500 RPM for an extended period of time, the resonating of the flexplate will probably not cause any problems. If it's of concern to you, almost any modification you do to the flex plate will change the resonate frequency. Usually stiffening it raises the frequency and reducing the stiffness lowers it, just like tuning a guitar string. If it was mine, I would take a look at it periodically during the test flying, then add it onto my inspection list for the annual inspections. The Stinsons with a McCauley metal prop had a placard advising not run between something like 2100 - 2300 RPM. That was due to a resonant freqency between the engine and the prop that would eventually cause crankshaft cracking, usually in the keyway for the flywheel on the back end of the engine. The vibration from the McCauley prop was noticeable at those RPMs. Since you have a wood prop, that failure mode would be most unusual as wood props typically have such a low resonance that they almost never cause a harmonic vibration. Jeff Scott ________________________________________________________________ The best thing to hit the Internet in years - Juno SpeedBand! Surf the Web up to FIVE TIMES FASTER! Only $14.95/ month - visit www.juno.com to sign up today! ------------------------------ Message: 2 Date: Thu, 5 Aug 2004 21:45:27 +0200 From: "Dene Collett \(SA\)" Subject: KR> tortional loads +early friday To: "krnet" Message-ID: <000901c47b2e$abb20820$37e5fea9@telkomsa127179> Content-Type: text/plain; charset="iso-8859-1" Hi KR heads As some of you know, I am working on a full retract tricycle gear on my rendition of a KR2S. Tonight I went to look at some wood for the forward outer spars at a friend of mine who is a very respected person in the experimental world over here. I was discussing the retract system with him and he brought up a point that I had not considdered at all. As my retract system requires that the bottom wing skin of the stubwings be split basically from root to outboard end in order for the gear to retract into the wing. This means that the bottom skin will no linger be continuous between the spars. My question is: What, if any, tortional loads does the skin carry under normal conditions due to forces applied by ailerons, etc. and what effect will the splitting of the skin in order to accomodate the gear have on wing strength. As a bit of background, my gear will consist of a 1.5" 4130 tube between the spars supported each end by a bearing mounted in a piece of aluminuim that bolts onto the spars by picking up the W.A.F bolts. To this tube will be another 1.5" tube welded at 90* to it forming the gear leg. At the bottom of this will be a trailing link arrangement with a damper. The tube between the spars will be mounted almost at the outboard end of the stubwings and the gear will retract towards the fuselage just clearing it to sit completely inside the wing. Any thoughts from those in the know will be greatly appreciated. Thank you next day: On a less serious note, I was fortunate enough to have had the "WHISPER" experience today. After work I was invited to go on a "test" flight for about half an hour down the coast here. This plane is remarkable. I was amased when Russell (the designer,builder &pilot) let go of the stick immediately as the tail came off the groung and the plane just took off and flew straight ahead in a steady climb all by itself! Takeoff roll was less than 80metres with a 13 knot headwind! Deploying the spoilers on final brings the glide slope from 28:1 down to 8:1, feels like the seat has fallen out of the bottom of the plane. For more info see my signature line. Dene Collett KR2S-RT builder Port Elizabeth South Africa mailto: dene.collett@telkomsa.net P.S: checkout www.whisperaircraft.com ------------------------------ Message: 3 Date: Thu, 5 Aug 2004 15:15:21 -0600 (Mountain Standard Time) From: "gleone" Subject: Re: @WL KR> tortional loads +early friday To: Message-ID: <4112A369.000004.02552@YOUR-FD6NVJCER4> Content-Type: Text/Plain; charset="iso-8859-1" I remember seeing a picture of a KR-2 with retractable tricycle gear. The problem is, I don't remember where. Anyway, if anyone else remembers seeing that picture and (hopefully when and where), you might want to track down the builder of that plane and ask how he/she did it. All I remember is it was within the last year or two. Gene Leone, Worland, Wyoming When you give a lesson in meanness to a critter or a person, don't be surprised if they learn their lesson. -------Original Message------- From: KRnet Date: 08/05/04 14:52:51 To: krnet Subject: @WL KR> tortional loads +early friday Hi KR heads As some of you know, I am working on a full retract tricycle gear on my rendition of a KR2S. Tonight I went to look at some wood for the forward outer spars at a friend of mine who is a very respected person in the experimental world over here. I was discussing the retract system with him and he brought up a point that I had not considdered at all. As my retract system requires that the bottom wing skin of the stubwings be split basically from root to outboard end in order for the gear to retract into the wing. This means that the bottom skin will no linger be continuous between the spars. My question is: What, if any, tortional loads does the skin carry under normal conditions due to forces applied by ailerons, etc. and what effect will the splitting of the skin in order to accomodate the gear have on wing strength. As a bit of background, my gear will consist of a 1.5" 4130 tube between the spars supported each end by a bearing mounted in a piece of aluminuim that bolts onto the spars by picking up the W.A.F bolts. To this tube will be another 1.5" tube welded at 90* to it forming the gear leg. At the bottom of this will be a trailing link arrangement with a damper. The tube between the spars will be mounted almost at the outboard end of the stubwings and the gear will retract towards the fuselage just clearing it to sit completely inside the wing. Any thoughts from those in the know will be greatly appreciated. Thank you next day: On a less serious note, I was fortunate enough to have had the "WHISPER" experience today. After work I was invited to go on a "test" flight for about half an hour down the coast here. This plane is remarkable. I was amased when Russell (the designer,builder &pilot) let go of the stick immediately as the tail came off the groung and the plane just took off and flew straight ahead in a steady climb all by itself! Takeoff roll was less than 80metres with a 13 knot headwind! Deploying the spoilers on final brings the glide slope from 28:1 down to 8:1, feels like the seat has fallen out of the bottom of the plane. For more info see my signature line. Dene Collett KR2S-RT builder Port Elizabeth South Africa mailto: dene.collett@telkomsa.net P.S: checkout www.whisperaircraft.com _______________________________________ 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: 4 Date: Thu, 05 Aug 2004 16:26:52 -0500 From: "Oscar Zuniga" Subject: KR> retract gears/was something else To: krnet@mylist.net Message-ID: Content-Type: text/plain; format=flowed gleone wrote- >I remember seeing a picture of a KR-2 with retractable tricycle gear. >The problem is, I don't remember where. Probably Ron Eason's setup, which used to be at http://www.freeyellow.com but gets a 404 error now. If Ron is still on the list maybe he'll let on to where the pix are now. Oscar Zuniga San Antonio, TX mailto: taildrags@hotmail.com website at http://www.flysquirrel.net ------------------------------ Message: 5 Date: Thu, 5 Aug 2004 17:39:24 -0400 (Eastern Standard Time) From: "Dan Heath" Subject: KR> bottom skin will no linger be continuous between the spars To: "krnet@mylist.net" Message-ID: <4112A90C.000006.03100@COMPUTER> Content-Type: Text/Plain; charset="iso-8859-1" RE: This means that the bottom skin will no linger be continuous between the spars Dean, Remember that the original KR design had a retractable main gear. There were many flying with the bottom skin not flat and contiguous, however, it was all glassed into the hole. Also, John Shafer showed up at the gathering last year in a retractable tri-gear. You may see some pictures of it on the krgathering web site. "There is a time for building and a time for GOING TO THE GATHERING, and the time for building has long since expired." See you in Mt. Vernon - 2004 - KR Gathering http://KRGathering.org See N64KR at http://KR-Builder.org - Then click on the pics Daniel R. Heath - Columbia, SC ------------------------------ Message: 6 Date: Thu, 5 Aug 2004 14:46:45 -0700 (PDT) From: Scott Cable Subject: Re: KR> tortional loads & cereal box experiments! To: KRnet Message-ID: <20040805214645.33283.qmail@web53001.mail.yahoo.com> Content-Type: text/plain; charset=us-ascii Dean & Netters: By cutting a hole in the lower skin, you've basicly removed the Load Path for the torsional load to sheer out through the lower wing skin. The bigger the hole, more of the load path is removed. Some of the airload will be reintroduced by way of the the gear door or fairing, but you still must replace the missing material / load path by some other means. Usually a doubler framed out with intercostals is the perferred method of doing this. Think of the stub wing as a torque box, with the spars and skins sharing the load. Try this little experiment: Take a cereal box with the ends taped shut. Hold the box with the long side horizontally and try to twist the box out of shape. Note how much "force" is required to deflect and twist the box out of shape. Now cut a hole (leave like an inch perimeter with your hole) in the bottom horizontal face, and try your experiment over. See how little force is required to twist the box out of shape now? Now add some "ribs" to attach to the upper "skin" and to the front and back of the box. Re-try your experiment yet one last time. You'll notice that it is much more difficult to twist the box out of shape again. >From this little experiment we learned that by adding some ribs we can >substantially increase the stiffeness of the wing torque box, which is what you should try to incorporate into your modification. add some ribs and doublers. just my thoughts...Hope this helps Scott "Dene Collett (SA)" wrote: My question is: What, if any, tortional loads does the skin carry under normal conditions due to forces applied by ailerons, etc. and what effect will the splitting of the skin in order to accomodate the gear have on wing strength. Scott Cable KR-2S # 735 Wright City, MO s2cable1@yahoo.com --------------------------------- Do you Yahoo!? Yahoo! Mail - 50x more storage than other providers! ------------------------------ Message: 7 Date: Thu, 5 Aug 2004 17:13:42 -0500 From: "Ron Eason" Subject: Re: @WL KR> tortional loads +early friday To: "KRnet" Message-ID: <027901c47b39$77a57160$6601a8c0@CADENGINEERING> Content-Type: text/plain; charset="iso-8859-1" I have a retractable Tri-gear under construction at www.jrl-engineering.com on the hanger page. Photos are old now the plane is on the gears now, I am working on the canopy and instrument panel. I will update them when I have enough time, it's not a priority for me at this time. KRron ----- Original Message ----- From: "gleone" To: Sent: Thursday, August 05, 2004 4:15 PM Subject: Re: @WL KR> tortional loads +early friday > I remember seeing a picture of a KR-2 with retractable tricycle gear. > The problem is, I don't remember where. Anyway, if anyone else > remembers seeing > that picture and (hopefully when and where), you might want to track > down the builder of that plane and ask how he/she did it. All I > remember is it was within the last year or two. > > Gene Leone, Worland, Wyoming > > When you give a lesson in meanness to a critter or a person, don't be > surprised if they learn their lesson. -------Original Message------- > > From: KRnet > Date: 08/05/04 14:52:51 > To: krnet > Subject: @WL KR> tortional loads +early friday > > Hi KR heads > As some of you know, I am working on a full retract tricycle gear on > my rendition of a KR2S. Tonight I went to look at some wood for the > forward outer spars at a friend of mine who is a very respected person > in the experimental world over here. I was discussing the retract > system with him and he brought up a point that > I had not considdered at all. As my retract system requires that the bottom > wing skin of the stubwings be split basically from root to outboard > end in order for the gear to retract into the wing. This means that > the bottom skin > will no linger be continuous between the spars. > > My question is: What, if any, tortional loads does the skin carry > under normal conditions due to forces applied by ailerons, etc. and > what effect will the splitting of the skin in order to accomodate the > gear have on wing > strength. > > As a bit of background, my gear will consist of a 1.5" 4130 tube > between the > spars supported each end by a bearing mounted in a piece of aluminuim > that bolts onto the spars by picking up the W.A.F bolts. To this tube > will be another 1.5" tube welded at 90* to it forming the gear leg. At > the bottom of > this will be a trailing link arrangement with a damper. The tube > between the spars will be mounted almost at the outboard end of the > stubwings and the gear will retract towards the fuselage just clearing > it to sit completely inside the wing. > > Any thoughts from those in the know will be greatly appreciated. Thank > you next day: > On a less serious note, I was fortunate enough to have had the "WHISPER" > experience today. After work I was invited to go on a "test" flight for > about half an hour down the coast here. This plane is remarkable. I was > amased when Russell (the designer,builder &pilot) let go of the stick > immediately as the tail came off the groung and the plane just took off and > flew straight ahead in a steady climb all by itself! Takeoff roll was > less than 80metres with a 13 knot headwind! Deploying the spoilers on > final brings the glide slope from 28:1 down to 8:1, feels like the > seat has fallen > out of the bottom of the plane. > For more info see my signature line. > Dene Collett > KR2S-RT builder > Port Elizabeth > South Africa > mailto: dene.collett@telkomsa.net > P.S: checkout www.whisperaircraft.com > > > > _______________________________________ > to UNsubscribe from KRnet, send a message to KRnet-leave@mylist.net > please see other KRnet info at http://www.krnet.org/info.html > > _______________________________________ > 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 346, Issue 60 ************************************** ================================== ABC Amber Outlook Converter v4.20 Trial version ==================================