---------------------------------------------------------- KIS-List Digest Archive --- Total Messages Posted Sun 07/04/10: 8 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 04:39 AM - KIS TR-1 Aerodynamics () 2. 05:30 AM - Re: KIS TR-1 Aerodynamics (F. Tim Yoder) 3. 05:33 AM - Nose Slam 1 (tmclam@comcast.net) 4. 06:33 AM - Nose Slam 1.5 (tmclam@comcast.net) 5. 10:53 AM - Re: Nose Slam 1 (Scott Stearns) 6. 12:10 PM - Re: KIS TR-1 Aerodynamics (Mark Kettering) 7. 02:43 PM - SV: Re: KIS IT-1 Aerodynamics (Hans Christian Erstad) 8. 05:13 PM - Re: Nose Slam 1.5 (F. Tim Yoder) ________________________________ Message 1 _____________________________________ Time: 04:39:43 AM PST US From: Subject: KIS-List: KIS TR-1 Aerodynamics 7/4/2010 Hello Mark, You wrote: 1) "We should also consider that since these planes are home built no two are exactly alike so they may not have the same exact handling qualities." True. 2) "One Tomahawk he flew would recover from a spin. Another would not." Must have been a harsh touch down when it would not. I also recall reading while that fiasco was going on that the production Tomahawk wings had fewer leading edge ribs than called for in the original designed and built test items. This economy measure permitted wing distortion under load and unpredictable performance results. 3) "I moved my main gear contact point forward by making a flox wedge between the gear and the fuselage so the main gear is now angled slightly forward." I also made this modification during construction. Maybe some day we can make some exact measurements to see the fore and aft location of our main gear axles with regard to some accepted base point such as the nose gear axle or fire wall. 4) "...... this fully eliminate the landing nose slam ......" But I did not get this definitive result. Maybe I need to start landing with full nose up trim to ensure the lightest back stick force on touchdown. My center stop spring bias pitch trim system has undergone some recent changes as a result of trying to do away with a taped on bent aluminum tab. The Ray Allen pitch trim motor does not have quite enough travel to fully meet my needs. It seems pretty well balanced now -- just barely enough nose up and barely enough nose down at each end of travel so I am reluctant to further tweak it by changing springs or spacers. It is a bitch to work on because the system is buried just forward of the pitch control idler. Are you landing with any engine RPM above idle? 'OC' Baker Says: "The best investment we can make is the time and effort to gather and understand knowledge." ======================================================= ----- Original Message ----- From: "Mark Kettering" Sent: Saturday, July 03, 2010 6:41 PM Subject: Re: KIS-List: Re: KIS IT-1 Aerodynamics > Hello OC, > > We should also consider that since these planes are home built no two are > exactly alike so they may not have the same exact handling qualities. At > times even production aircraft are not the same. My flight test > engineering instructor once told a story about flight testing Piper > Tomahawks. He said no two had the same spin entry and spin recovery > handling. One Tomahawk he flew would recover from a spin. Another would > not. > > In any case, I think the holding the nose off when landing after the mains > contact is not really an elevator issue. I think it is a main gear > location issue. I once did a quick calculation and came to the conclusion > the main gear is too far aft. When on the ground the force due to the > main gear (an up force that is aft of the CG) puts a nose down moment on > the aircraft making the nose slam down. Of course the main gear on a > trigear plane needs to be aft of the CG but the more aft it is the larger > the nose down moment until it overcome the maximum nose up moment the > horizontal tail can generate. > > This too far aft main gear also makes for a potential to over rotate on > takeoff. As the main gear lift off the nose down moment due to the main > gear is gone so if the pilot does not reduce the elevator pitch up as this > happens the plane will pitch up. > > There is no reason to live with this issue. Moving the main gear contact > point forward is very simple. I moved my main gear contact point forward > by making a flox wedge between the gear and the fuselage so the main gear > is now angled slightly forward. Not only does this fully eliminate the > landing nose slam but also make the takeoffs much nicer with less pilot > effort. > > Mark ________________________________ Message 2 _____________________________________ Time: 05:30:14 AM PST US From: "F. Tim Yoder" Subject: Re: KIS-List: KIS TR-1 Aerodynamics I built in the elevator extension and have always been able to hold the nose wheel off at touch down. Why don't we level the plane and drop a plumb line down to the floor from the firewall and measure to the gear axle centerlines and compare notes. Tim ----- Original Message ----- From: Sent: Sunday, July 04, 2010 4:38 AM Subject: KIS-List: KIS TR-1 Aerodynamics > > 7/4/2010 > > Hello Mark, You wrote: > > 1) "We should also consider that since these planes are home built no two > are exactly alike so they may not have the same exact handling qualities." > > True. > > 2) "One Tomahawk he flew would recover from a spin. Another would not." > > Must have been a harsh touch down when it would not. > > I also recall reading while that fiasco was going on that the production > Tomahawk wings had fewer leading edge ribs than called for in the original > designed and built test items. This economy measure permitted wing > distortion under load and unpredictable performance results. > > 3) "I moved my main gear contact point forward by making a flox wedge > between the gear and the fuselage so the main gear is now angled slightly > forward." > > I also made this modification during construction. Maybe some day we can > make some exact measurements to see the fore and aft location of our main > gear axles with regard to some accepted base point such as the nose gear > axle or fire wall. > > 4) "...... this fully eliminate the landing nose slam ......" > > But I did not get this definitive result. Maybe I need to start landing > with full nose up trim to ensure the lightest back stick force on > touchdown. My center stop spring bias pitch trim system has undergone some > recent changes as a result of trying to do away with a taped on bent > aluminum tab. The Ray Allen pitch trim motor does not have quite enough > travel to fully meet my needs. It seems pretty well balanced now -- just > barely enough nose up and barely enough nose down at each end of travel so > I am reluctant to further tweak it by changing springs or spacers. It is a > bitch to work on because the system is buried just forward of the pitch > control idler. > > Are you landing with any engine RPM above idle? > > 'OC' Baker Says: "The best investment we can make is the time and effort > to gather and understand knowledge." > > ======================================================= > ----- Original Message ----- > From: "Mark Kettering" > To: > Sent: Saturday, July 03, 2010 6:41 PM > Subject: Re: KIS-List: Re: KIS IT-1 Aerodynamics > > >> Hello OC, >> >> We should also consider that since these planes are home built no two are >> exactly alike so they may not have the same exact handling qualities. At >> times even production aircraft are not the same. My flight test >> engineering instructor once told a story about flight testing Piper >> Tomahawks. He said no two had the same spin entry and spin recovery >> handling. One Tomahawk he flew would recover from a spin. Another would >> not. >> >> In any case, I think the holding the nose off when landing after the >> mains contact is not really an elevator issue. I think it is a main gear >> location issue. I once did a quick calculation and came to the >> conclusion the main gear is too far aft. When on the ground the force >> due to the main gear (an up force that is aft of the CG) puts a nose down >> moment on the aircraft making the nose slam down. Of course the main >> gear on a trigear plane needs to be aft of the CG but the more aft it is >> the larger the nose down moment until it overcome the maximum nose up >> moment the horizontal tail can generate. >> >> This too far aft main gear also makes for a potential to over rotate on >> takeoff. As the main gear lift off the nose down moment due to the main >> gear is gone so if the pilot does not reduce the elevator pitch up as >> this happens the plane will pitch up. >> >> There is no reason to live with this issue. Moving the main gear contact >> point forward is very simple. I moved my main gear contact point forward >> by making a flox wedge between the gear and the fuselage so the main gear >> is now angled slightly forward. Not only does this fully eliminate the >> landing nose slam but also make the takeoffs much nicer with less pilot >> effort. >> >> Mark > > > ________________________________ Message 3 _____________________________________ Time: 05:33:41 AM PST US From: tmclam@comcast.net Subject: KIS-List: Nose Slam 1 OC,Mark,Rich and all These recent discussions are fantastic.More to the point. OC perhaps removing approximately 20 # forward of the main gear would help the "nose slam problem".!0 # under the Spinner could be demonstrated by temporarily using a borrowed wood propeller.If this does not quite do it ,we should all take a hard look at the new Simplified Dynon basic 6 displays.The larger one is visible in bright daylight. Use of these new devices allows the removal of Vacuum pumps Vacuum hoses ,gages,Regulators and so on. Heavy Attitude Horizon and Directional Gyro We should easily obtain a significant instrument panel weight reduction.In addition a 20# forward weight reduction will reduce trim drag and may reduce cruise angle of attack[which equals big time drag]. These new postage size Electronic Gyros are amazing,I think? Ted ________________________________ Message 4 _____________________________________ Time: 06:33:15 AM PST US From: tmclam@comcast.net Subject: KIS-List: Nose Slam 1.5 OC Please dont feel offended but knowing what i am capable of doing are you sure you installed the main gear wedges in the right direction? Happy Fourth Ted ________________________________ Message 5 _____________________________________ Time: 10:53:03 AM PST US From: Scott Stearns Subject: Re: KIS-List: Nose Slam 1 I have two dynons in my panel.- A D-100 for flight insturments and a D-18 0 which has both flight instruments and engine instruments.- They also ha ve battery backups that work for 1.5 hours.- My experience with them has been very good and it's also easy to download the data files from each flig ht which has been a huge help during flight testing.--- - Sco --- On Sun, 7/4/10, tmclam@comcast.net wrote: From: tmclam@comcast.net Subject: KIS-List: Nose Slam 1 #yiv605069051 p {margin:0;} OC,Mark,Rich and all These recent discussions are fantastic.More to the point. -------- OC perhaps removing approximately 20 # forward of the main gear would help the "nose slam problem".!0 # under the Spinner cou ld be demonstrated by temporarily using a borrowed wood propeller.If this d oes not quite do it ,we should all take a hard look at the new Simplified D ynon basic 6 displays.The larger one is visible in bright daylight. -Use of these new devices allows the removal of ------------------------- ----------------- Vacuum pumps ------------------------- ----------------- Vacuum hoses ,gages,Reg ulators and so on. ------------------------- ----------------- Heavy Attitude Horizon and Directional Gyro We should easily obtain a significant instrument panel weight reduction.In addition a 20# forward weight reduction will reduce trim drag and may reduc e cruise angle of attack[which equals big time drag]. ------------ These new postage size Electronic Gyro s are amazing,I think? ------------------------- ------------------------- ------------------------- --------------- Ted =0A=0A=0A ________________________________ Message 6 _____________________________________ Time: 12:10:05 PM PST US From: Mark Kettering Subject: Re: KIS-List: KIS TR-1 Aerodynamics Hi OC, > >2) "One Tomahawk he flew would recover from a spin. Another would not." > >Must have been a harsh touch down when it would not. The plane was fully destroyed. The pilot had entered the spin at about 11,500 feet and after 3 turns tried to recover until he was at 4500 feet then removed himself and floated safely to the ground. >I also recall reading while that fiasco was going on that the production >Tomahawk wings had fewer leading edge ribs than called for in the original >designed and built test items. This economy measure permitted wing >distortion under load and unpredictable performance results. This was also what he told the class at the time. >3) "I moved my main gear contact point forward by making a flox wedge >between the gear and the fuselage so the main gear is now angled slightly >forward." > >I also made this modification during construction. Maybe some day we can >make some exact measurements to see the fore and aft location of our main >gear axles with regard to some accepted base point such as the nose gear >axle or fire wall. > >4) "...... this fully eliminate the landing nose slam ......" > >But I did not get this definitive result. Maybe I need to start landing with >full nose up trim to ensure the lightest back stick force on touchdown. My >center stop spring bias pitch trim system has undergone some recent changes >as a result of trying to do away with a taped on bent aluminum tab. The Ray >Allen pitch trim motor does not have quite enough travel to fully meet my >needs. It seems pretty well balanced now -- just barely enough nose up and >barely enough nose down at each end of travel so I am reluctant to further >tweak it by changing springs or spacers. It is a bitch to work on because >the system is buried just forward of the pitch control idler. I have a full manual trim tab like on Rich's original TR1. I am big fan of this simple and fairly direct system. >Are you landing with any engine RPM above idle? No, I generally touch down with power at idle. Depending on the situation, I use a small amount of power to help slow decent but only right at the start of the flair. After that it is back to idle for the actual touch down. I have also landed fully no power from decent to touch down and still have not had a problem with keeping to nose off. At the moment I can not measure my main gear location since the plane is disassembled for repainting and a new engine but will when I get a chance. I can not find my original notes and calculations on the subject. Of course having the aircraft loaded to full aft CG helps reduce (mask?) the main gear too far aft situation. But having the main gear more forward helps in any loading condition. Mark ________________________________ Message 7 _____________________________________ Time: 02:43:14 PM PST US From: "Hans Christian Erstad" Subject: SV: KIS-List: Re: KIS IT-1 Aerodynamics 'OC', Mark and others discussing the KIS 1 handling. I have flown my KIS 1 for 10 years now, and I agree with 'OC' comments about the handling with respect to difficulties making consistent landings and keeping the nose wheel up. I built my KIS 100% according to the manual. This include tilting the main gear slightly forward to get the wheels at the correct station (can't remember what STA thou). Flying alone with no luggage means max forward CG. Flying with a passenger and luggage, placing the CG max aft, make it easier to keep the nose wheel up after landing (but not for ever :) About the wing/fuselage fairing. I have meet Julian several times at fly-in. He told that the fairing modification made the landings with a low approach speed a lot easier. Why not believe his experience? I think he is the only one to make the modification, and having experiencd what difference it makes. I have fairing modification on my to-do list. But I may never come to that item on my list, as I feel the landings are still OK, and I do not operate from runways shorter than 800 meters. I usually keep a little power on in the flare. Regards, Hans Christian, KIS #032 -----Opprinnelig melding----- Fra: owner-kis-list-server@matronics.com [mailto:owner-kis-list-server@matronics.com] P vegne av bakerocb@cox.net Sendt: 3. juli 2010 18:15 Til: kis-list@matronics.com; Kettering, Mark Emne: Re: KIS-List: Re: KIS IT-1 Aerodynamics 7/3/2010 Hello Mark, Thanks for your reply, the good wishes, and the page from Stinton's book. You wrote: 1) "I am not convinced there is an elevator problem being caused by separation in this area with my aircraft. I have never had a problem with elevator authority up to stall both in and out of ground effect." We may not understand completely what is going on pitch wise in the landing flare and ground effect with the KIS TR-1, but it would seem that enough pilots have reported enough surprises / problems in this arena that we: A) Don't have a firm grasp on the nature of what is happening in this arena; B) Don't have agreement on the existence or extent of the surprises / problems in this arena; and C) Don't have agreement on whether a solution is required or what that solution should be. I do agree with Rich that the problem is not dangerous, but I am still a bit annoyed that after flying 50 years plus, 5,000 hours plus over all, and almost 300 hours in this plane that I can't do a consistent flare and touchdown on every landing. Further the nose wheel touches down immediately after the main gear touches down almost every time. On a few rare occasions I have kept the nose wheel from touching down, but when I make a determined attempt to keep the nose wheel from touching down I am likely to do a little re airborne skip. 2) "I have not seen the video and am waiting on getting it from Scott." If my DVD copy efforts have been successful I am willing to make more copies and send them to interested KIS TR-1 pilots -- this is what Julian had in mind in sending me the DVD. You will see video of yarn tufts flowing forward against the direction of travel in the wing to fuselage fillet area. Don't know what this is doing to the air flow back at the horizontal tail surfaces, but it can't be all good. 'OC' Baker Says: "The best investment we can make is the time and effort to gather and understand knowledge." ============================================================ ----- Original Message ----- From: "Mark Kettering" Sent: Thursday, July 01, 2010 5:08 PM Subject: Re: KIS-List: Re: KIS IT-1 Aerodynamics > Hi OC, > > Good to hear you are not crashing that often anymore. > > I very much like Stinton's book but it is a bit empirical at times with > not a lot of data to back it up. In any case here is page 171. With a > quick scan I did not see more on this subject. I would still check out > the book if you can find it. > > I am not convinced there is an elevator problem being caused by separation > in this area with my aircraft. I have never had a problem with elevator > authority up to stall both in and out of ground effect. I have not seen > the video and am waiting on getting it from Scott. The one picture I have > seen did show some turbulence (but it would be guessing to call it > separation) at the aft wing root. But the flow over the tail and aft part > of the fuselage still looks good. Maybe this turbulence is really just > the very start of the stall? If that is the case the small root faring > may start the stall. If so maybe this is not all a bad thing since at the > root is the best place for the stall to start. > > Of course I do want to reduce drag since I NEED to be faster than Scott. > > Mark Kettering ________________________________ Message 8 _____________________________________ Time: 05:13:00 PM PST US From: "F. Tim Yoder" Subject: Re: KIS-List: Nose Slam 1.5 OUCH!!! ----- Original Message ----- From: tmclam@comcast.net To: kis-list@matronics.com Sent: Sunday, July 04, 2010 6:26 AM Subject: KIS-List: Nose Slam 1.5 OC Please dont feel offended but knowing what i am capable of doing are you sure you installed the main gear wedges in the right direction? Happy Fourth Ted ------------------------------------------------------------------------------------- Other Matronics Email List Services ------------------------------------------------------------------------------------- Post A New Message kis-list@matronics.com UN/SUBSCRIBE http://www.matronics.com/subscription List FAQ http://www.matronics.com/FAQ/KIS-List.htm Web Forum Interface To Lists http://forums.matronics.com Matronics List Wiki http://wiki.matronics.com Full Archive Search Engine http://www.matronics.com/search 7-Day List Browse http://www.matronics.com/browse/kis-list Browse Digests http://www.matronics.com/digest/kis-list Browse Other Lists http://www.matronics.com/browse Live Online Chat! http://www.matronics.com/chat Archive Downloading http://www.matronics.com/archives Photo Share http://www.matronics.com/photoshare Other Email Lists http://www.matronics.com/emaillists Contributions http://www.matronics.com/contribution ------------------------------------------------------------------------------------- These Email List Services are sponsored solely by Matronics and through the generous Contributions of its members.