From: owner-krnet-l-digest@lists.teleport.com (krnet-l-digest) To: krnet-l-digest@lists.teleport.com Subject: krnet-l-digest V1 #50 Reply-To: krnet-l-digest Sender: owner-krnet-l-digest@lists.teleport.com Errors-To: owner-krnet-l-digest@lists.teleport.com Precedence: bulk krnet-l-digest Wednesday, June 25 1997 Volume 01 : Number 050 ---------------------------------------------------------------------- Date: Wed, 25 Jun 1997 09:18:09 From: brian whatcott Subject: Re: KR: KR longitudinal stability At 08:34 6/25/97 -0700, Ted Jones wrote: >Donald Reid wrote: >> ... >> The mass balance should reduce the stick forces which will make the controls >> more sensitive. More sensitive means easier to overstress the aircraft, >> less sensitive means more forearm strength to control. Pick a happy medium. >> -- >> Don Reid >> donreid@erols.com > >Don, please help me out here: I have been under the impression that mass >balance in a control surface was used to inhibit flutter by adding >weight forward of the hinge to equalize the weight of the control >surface forward and aft of the hinge -- or approach equal weights. ... >However, if surface area of an elevator, for example, is added forward >of the hinge line, this would most decidedly lighten the load in the >control system while having a minimal affect on flutter unless that >portion forward also incorporated weights to improve mass balance. > >What am I missing? > >Ted Jones > I think you have it right, Ted. On an allied topic: mass balancing is sometimes specified to 80% balance the surface rather than 100% This COULD be because a lollipop on a stick has a greater rotational moment of inertia than a control surface whose weight is usually distributed but a little closer to the hinge than half way aft. Regards brian whatcott Altus OK ------------------------------ Date: Wed, 25 Jun 1997 09:29:26 -0500 From: kb5lxl@juno.com Subject: Re: KR:Web Page Apology Hello Friends, I want to thank Ross for getting my KRNet subscription changed. Mike Mimms had been gracious enough to post the address of my construction page. However, due to bad service and even worse customer service, I canceled my AOL. I am in the process of building a new and much improved web page. I will publish the address when it is complete. I am truly sorry for any inconvenience this interruption may have caused. In an effort to re numerate for the inconvenience, I would like to share the following with you. Are you tied down to one E-mail address, and having to sort through the KRNet stuff to find your personal E-mail? If you change services are you going to lose your E-mail address (and KRNet subscription like I did)? There is an easy fix and it is FREE! I found an E-Mail service called JUNO. The service is entirely free. No monthly charges, in fact there is no charge at all. Hard to believe, but there are no strings attached. You can get this service ( and set up the KRNet on it) by going to: http://www.juno.com and downloading the software. You can set up several E-Mail addresses if you like. This is strictly an E-Mail service and not an online Service. One other advantage, because you are only sending and receiving E-mail, and not browsing, it appears that COOKIES are not embedded. After two weeks of use, Not one single E-Mail junk mail!!!!!! Good luck and thanks Ricky Pitman Marion, Arkansas KR Builder ------------------------------ Date: Wed, 25 Jun 1997 07:35:55 -0700 From: MARVIN MCCOY Subject: Re: KR: Re: EAA Northwest Fly-in, Arlington, WA. John Bouyea wrote: > > I'm planning on going as well. I'd like to make it a day trip if we know > WHICH day everyone is gathering @ the fire pit. Both Saturday & Sunday > have been suggested; is there an agreement as which day will draw the > greatest number of attendees? > ----------------- John: I believe some one could not make it on Saturday so I think we are planning to meet on Sunday morning the 13th at 9:00am. Hope to see you there. Marvin McCoy Seattle, WA. North end of Boeing Field Mr.Marvin@worldnet.att.net - ----------- ------------------------------ Date: Wed, 25 Jun 1997 08:21:04 -0700 From: Micheal Mims Subject: Re: KR: Source for .5 inch 4130 strap At 01:00 AM 6/25/97 -0700, you wrote: > Hey Mike, >All I can say is good luck, I built a set of brackets from a sheet of 4130 >what a pain, and when I was done I wasn't happy. So I bit the bullet and >ordered them from RR. > > Dave Moore Well my plan is to use 1.5 inch and 1 inch 4130 strap and just cut them to the appropriate length. I will pick up two new carbide bits Friday for the drill press (should help). There is no way your gona get me to cut all those lightning holes! I will just round the corners on the bench grinder and drill the holes and call it good! I still haven't located any .5 inch strap so I will use 1 inch and install them so the excess material is installed towards the center of the aft spar. I would buy the fittings from Rand but they wont work for my application. ________________________________ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Micheal Mims Just Plane Nutts mailto:mimsmand@ix.netcom.com http://www.netcom.com/~mimsmand ------------------------------ Date: Wed, 25 Jun 1997 11:47:27 -0400 From: smithr Subject: KR: Re: stick length > On above point #3: This sounds good for increasing stick force > >(desirable) but in physics you don't get something for nothing. It will > >also yield more degrees of elevator deflection per inch of stick > >movement. This might not be good if you are trying to reduce pitchiness. > > The KR needs both more stick force and (slightly) more stick movement > >per deg of elevator deflection. I don't know what will give both. > >Possibly a non-linear cam. > > > > Your right but I plan to leave the stick the stock length. I noticed some > builders have cut the stick down in an attempt to decrease the stick > sensitivity (give themselves less leverage). Hopefully there will be some > sort of happy medium and the longer stick will not cancel out the increased > stick pressure. I took measurements from various aircraft at the airport and > decided 1 inch will help some. Its one of those things that will be a "wait > and see". :-) > Micheal Mims > Just Plane Nutts > mailto:mimsmand@ix.netcom.com > > http://www.netcom.com/~mimsmand My ride in a KR changed all my views on stick length. Prior to the ride I had planned that a longer stick was desirable. During the ride I learned 1) KR pilots tend to hold the stick near the base regardless of its length and 2) if you hold it up high without an armrest the PIO is very bad. I plan to use an armrest and hold the stick near the base. Bob SMith, Albany, NY ------------------------------ Date: Wed, 25 Jun 1997 10:55:21 -0500 From: kb5lxl@juno.com Subject: Re: KR:Web Page Apology Addendum to previous post: I just wanted to say that I have no financial ties to JUNO, am not kin to anyone associated with JUNO (as far as I know), and am not advertising for them as a solicitation. Also, you can probably get a KR type of E-mail address for use on the KR-Net. I just did. To E-Mail direct to me please use: KR2Builder@juno com Thanks again Ricky Pitman Marion, Arkansas ------------------------------ Date: Wed, 25 Jun 1997 09:23:40 -0700 From: Micheal Mims Subject: Re: KR: Re: stick length At 11:47 AM 6/25/97 -0400, you wrote: >My ride in a KR changed all my views on stick length. Prior to the ride >I had planned that a longer stick was desirable. During the ride I >learned 1) KR pilots tend to hold the stick near the base regardless of >its length and 2) if you hold it up high without an armrest the PIO is >very bad. I plan to use an armrest and hold the stick near the base. > >Bob SMith, Albany, NY > This is exactly what I am trying to get away from. By de-sensitizing the stick maybe this airplane could be flown like a normal flying machine. The ONLY way to control Troys KR when I was flying it was to hold the stick at the base. Theres something wrong with that picture! ________________________________ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Micheal Mims Just Plane Nutts mailto:mimsmand@ix.netcom.com http://www.netcom.com/~mimsmand ------------------------------ Date: Wed, 25 Jun 1997 12:46:55 -0400 From: smithr Subject: Re: KR: KR longitudinal stability Micheal Mims wrote: > I am not sure springs would give you the "feel" you would want though, but then again maybe they would?!? ------------------------------ Date: Wed, 25 Jun 1997 11:37:54 -0700 From: David Moore Subject: KR: Hershey Bar wing? Mike, You said one time, you were looking at a hershey bar wing (ala. Piper Cherokee), is that still your plan? Dave Moore David Moore Turnkey1@mscomm.com Hesperia, California ------------------------------ Date: Wed, 25 Jun 1997 14:04:03 -0500 (CDT) From: Steven A Eberhart Subject: Re: KR: KR longitudinal stability On Wed, 25 Jun 1997, smithr wrote: > Micheal Mims wrote: > > I am not sure springs would give you the "feel" you would want though, > but then again maybe they would?!? > I like everything I have read about stabilators with anti-servo tabs. For the same area you get a little more stability plus you can tailor the stick feel with the anti-servo tab gearing. Steve ------------------------------ Date: Wed, 25 Jun 1997 15:15:09 -0400 (EDT) From: TANDEM2@aol.com Subject: Re: KR: Re: EAA Northwest Fly-in, Arlington, WA. yes, we will be there on sunday at 9 at the pit, hope everyone will be there ------------------------------ Date: Wed, 25 Jun 1997 15:55:07 -0400 From: smithr Subject: KR: longitudinal stability How about a simple friction setup for the stick where the stick is held between 2 friction washers where you tighten the nut to increase the friction and stick force? Bob Smith, Albany, NY ------------------------------ Date: Mon, 23 Jun 1997 18:33:47 -0700 From: Donald Reid Subject: Re: KR: KR longitudinal stability Ted & Louisa Jones wrote: > > Don, please help me out here: I have been under the impression that mass > balance in a control surface was used to inhibit flutter by adding > weight forward of the hinge to equalize the weight of the control > surface forward and aft of the hinge -- or approach equal weights. > If my assumption is correct, the > effect of mass balancing would have no affect on sensativity -- or > minimal affect. > > However, if surface area of an elevator, for example, is added forward > of the hinge line, this would most decidedly lighten the load in the > control system while having a minimal affect on flutter unless that > portion forward also incorporated weights to improve mass balance. > > What am I missing? > > Ted Jones The mass balance does decrease the chances of flutter. My understanding of the mechanics is because the mass balance will change the natural frequency of vibration. This is outside of anything I really know about. I can't give a good explaination, so I won't try. As to sensativity: When the unbalanced elevator is displaced out of the streamline position, there will be a force created that is proportional to the displacement, the area of the control surface, and the square of the air velocity. This is the force that you feel in your hand and arm. If you go trailing edge up, the air load tries to push it back to the streamlined position. You have to maintain a back pressure on the stick to hold the elevator in position. The control system design guys talk about stick force / G. They mean the number of pounds of force you have to hold to create an extra 1G of loading. If this is a low number, a gentle pull on the stick can overstress the airframe and kill you. On the otherhand, it will feel like a fighter aircraft, you think about a change and it happens. With a balanced elevator, the same displacement will produce approximately the same force. (It will be a little bit less since the balance mass is in front of the hinge line and will create a counteracting air load) If the elevator is displaced trailing edge up, the mass balance will counteract by trying to pull the trailing edge back down. This subtracts out from the force that you must generate in your hand and arm. You end up with a lower stick force per G loading and this means a more sensative control system. I hope this explaination is helpful. - -- Don Reid donreid@erols.com ------------------------------ Date: Wed, 25 Jun 1997 13:59:10 -0700 From: Micheal Mims Subject: Re: KR: KR longitudinal stability At 02:04 PM 6/25/97 -0500, you wrote: >On Wed, 25 Jun 1997, smithr wrote: > >> Micheal Mims wrote: >> >> I am not sure springs would give you the "feel" you would want though, >> but then again maybe they would?!? >> > >I like everything I have read about stabilators with anti-servo tabs. >For the same area you get a little more stability plus you can tailor the >stick feel with the anti-servo tab gearing. > I just re-read some material in the book called "Flight Testing Homebuilt Aircraft" and he says to decrease control sensitivity decrease the control arm (move the control cables/ pushrod closer to the pivot point). I have read about Neico <-spelling? (Lancair) Aviation telling owners of certain models or the Lancair (early ones) to do the same, their AD said to move the pushrod 1 inch closer to the pivot. After a short discussion with my friend Brad, he decided to try it on his Dragonfly and he loves the results! I wish I could convince someone with a flying KR to give this a try!!! ________________________________ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Micheal Mims Just Plane Nutts mailto:mimsmand@ix.netcom.com http://www.netcom.com/~mimsmand ------------------------------ Date: Wed, 25 Jun 1997 13:59:27 -0700 From: Micheal Mims Subject: Re: KR: KR longitudinal stability At 06:33 PM 6/23/97 -0700, you wrote: >> What am I missing? >> >> Ted Jones > >The mass balance does decrease the chances of flutter. My understanding >of the mechanics is because the mass balance will change the natural >frequency of vibration. This is outside of anything I really know about. > I can't give a good explaination, so I won't try... Your not missing anyting you guys are just talking about two differnt anamals. I think one is thinking about a aerodynmic mass balance and the other is thinking about a counter balance weight. ________________________________ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Micheal Mims Just Plane Nutts mailto:mimsmand@ix.netcom.com http://www.netcom.com/~mimsmand ------------------------------ Date: Wed, 25 Jun 1997 18:29:56 EDT From: jscott.pilot@juno.com (Jeffrey E. Scott) Subject: Re: KR: Source for .5 inch 4130 strap I just bought a small sheet of the proper thickness of 4130 plate and made a drawing of what I wanted. My neighborhood machinist punched 'em out in his garage with his mill. Jeff Scott Los Alamos, NM - ---- Jeffrey Scott jscott.pilot@juno.com See construction of KR-2S N1213W at http://fly.hiwaay.net/~langford/kjeffs.html - ---- On Tue, 24 Jun 1997 14:21:44 -0700 Micheal Mims writes: >Has anyone found a source for the 1/2 inch 4130 strap used to make the >aft >wing attach fittings? I may locate a metal shop with a hydraulic floor >shear >and see if they will cut some for me. Or I could just use 1 inch for >the aft >fittings and 2 inch for the front. > >________________________________ >~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ >Micheal Mims >Just Plane Nutts >mailto:mimsmand@ix.netcom.com > >http://www.netcom.com/~mimsmand > > ------------------------------ Date: Wed, 25 Jun 1997 19:13:23 EDT From: jscott.pilot@juno.com (Jeffrey E. Scott) Subject: Re: KR: Night Flight??? Upon the inspection of the plane, it may be restricted to Daytime VFR, Day/Night VFR, or IFR in a check box on the inspection paperwork. The inspector looked at mine and said, "I see you have lights and strobes, do you want to be allowed night time VFR?" I answered "Yes." End of subject. It should say on the airworthiness Certificate as to what yours is restricted to. I have heard, but not verified that it can be difficult to get the Day VFR lifted to Day/Night VFR if it is already restricted as such on the airworthiness certificate. Jeff Scott Los Alamos, NM - ---- Jeffrey Scott jscott.pilot@juno.com See construction of KR-2S N1213W at http://fly.hiwaay.net/~langford/kjeffs.html - ---- On Wed, 25 Jun 1997 08:39:19 -0500 "Johnny Galindo" writes: >I am about to purchase a KR-2 so I was looking at the FAR's and when I >saw >this, I started wondering what it means to me. what constitutes >"otherwise >specifically authorized by the Administrator" ?? > > > >Sec. 91.319 Aircraft having experimental certificates: Operating >limitations. > > >d) Each person operating an aircraft that has an experimental >certificate >shall-- >(1) Advise each person carried of the experimental nature of the >aircraft; >(2) Operate under VFR, day only, unless otherwise specifically >authorized by >the Administrator; and >(3) Notify the control tower of the experimental nature of the >aircraft when >operating the aircraft into or out of airports with operating control >towers. >(e) The Administrator may prescribe additional limitations that the >Administrator considers necessary, including limitations on the >persons that >may be carried in the aircraft. >John Galindo >WK - (512)339-5394 >HM - (512)869-6227 > >Pager >===== >E-Mail to: >1167029@skymail.com > >or (800)Page-MCI >pin 1167029 > > ------------------------------ Date: Wed, 25 Jun 1997 19:13:23 EDT From: jscott.pilot@juno.com (Jeffrey E. Scott) Subject: KR: Re: stick length On Wed, 25 Jun 1997 11:47:27 -0400 smithr writes: >> On above point #3: This sounds good for increasing stick force >> >(desirable) but in physics you don't get something for nothing. It will >> >also yield more degrees of elevator deflection per inch of stick >> >movement. This might not be good if you are trying to reduce pitchiness. >> > The KR needs both more stick force and (slightly) more stick movement >> >per deg of elevator deflection. I don't know what will give both. >> >Possibly a non-linear cam. >> > >> >> Your right but I plan to leave the stick the stock length. I noticed some >> builders have cut the stick down in an attempt to decrease the stick >> sensitivity (give themselves less leverage). Hopefully there will be some >> sort of happy medium and the longer stick will not cancel out the increased >> stick pressure. I took measurements from various aircraft at the airport and >> decided 1 inch will help some. Its one of those things that will be >a "wait >> and see". :-) > >> Micheal Mims >> Just Plane Nutts >> mailto:mimsmand@ix.netcom.com >> >> http://www.netcom.com/~mimsmand > >My ride in a KR changed all my views on stick length. Prior to the ride >I had planned that a longer stick was desirable. During the ride I >learned 1) KR pilots tend to hold the stick near the base regardless of >its length and 2) if you hold it up high without an armrest the PIO is >very bad. I plan to use an armrest and hold the stick near the base. > >Bob SMith, Albany, NY > If I can use this as a comparison statement, I would say that my KR-2s with the standard KR-2 sized tail is significantly improved from the KR-2. Mine has center throttle quadrant and dual sticks. I just hold the stick in my left hand just the same as I have on every other left handed airplane including J-4 Cub, and Luscombe. Although the elevator forces are very light, I have learned a pretty good feel in a matter of 10 - 15 landings. Now that I have added a trim wedge under the elevator, in smooth air, it flies very nicely hands off. Just with my small amount of experience with this plane, I am of the opinion that it would benefit from more horizontal stab, but I wouldn't restrict the movement of the elevator with stops. You need the rest of the elevator control on landing. I also probably wouldn't add springs to add "feel" to it as the elevator does have a good feel, but it does take a couple of flights to adjust to the plane. My $.02 worth Jeff Scott Los Alamos, NM - ---- Jeffrey Scott jscott.pilot@juno.com See construction of KR-2S N1213W at http://fly.hiwaay.net/~langford/kjeffs.html - ---- ------------------------------ Date: Wed, 25 Jun 1997 17:05:03 -0700 From: Micheal Mims Subject: Re: KR: Re: stick length At 07:13 PM 6/25/97 EDT, you wrote: I am of the opinion that it would benefit >from more horizontal stab, but I wouldn't restrict the movement of the >elevator with stops. You need the rest of the elevator control on >landing. I also probably wouldn't add springs to add "feel" to it as the >elevator does have a good feel, but it does take a couple of flights to >adjust to the plane. > No, restricting the elevator to less than the published deflections would be asking for trouble! I think I will just mount the pushrod on the elevator 1 inch closer to the pivot and call it good. This has made an incredible difference on other aircraft with "sensitive controls". This was my original plan and I am sticking to it! :-) ________________________________ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Micheal Mims Just Plane Nutts mailto:mimsmand@ix.netcom.com http://www.netcom.com/~mimsmand ------------------------------ Date: Wed, 25 Jun 1997 17:43:32 -0700 From: enewbold@sprynet.com Subject: Re: KR: stick length >No, restricting the elevator to less than the published deflections would be >asking for trouble! I think I will just mount the pushrod on the elevator 1 >inch closer to the pivot and call it good. This has made an incredible >difference on other aircraft with "sensitive controls". This was my >original plan and I am sticking to it! :-) >Micheal Mims 1" closer to the pivot? At the elevator? If I understand you correctly, this would *increase* the amount of throw: -------.------------------. stab | elevator } -------^------------------` | / Pushrod == |+ / <----closer to pivot = more throw |*/ <----further from pivot = less throw `' Of course, I might be missing what you're saying . It wouldn't be the first time! Cheers, Ed newbold columbus, OH ------------------------------ Date: Wed, 25 Jun 1997 18:28:18 -0700 From: Micheal Mims Subject: Re: KR: stick length At 05:43 PM 6/25/97 -0700, you wrote: >1" closer to the pivot? At the elevator? If I understand you correctly, this >would *increase* the amount of throw: > > -------.------------------. > stab | elevator } > -------^------------------` > | / > Pushrod == |+ / <----closer to pivot = more throw > |*/ <----further from pivot = less throw > `' NO you got it! 1 inch closer is right. The elevator still has to be set to deflect up 30 degrees and down 20 degrees but the gearing is changed to give the elevator more mechanical advantage over the stick, increasing stick pressure. _______________________ ~~~~~~~~~~~~~~~~~~~~~~ Micheal Mims Just Plane Nutts in Irvine Ca. mailto:mimsmand@ix.netcom.com http://www.netcom.com/~mimsmand ------------------------------ Date: Wed, 25 Jun 1997 20:54:33 From: brian whatcott Subject: Re: KR: stick length At 18:28 6/25/97 -0700, Mich M wrote: >... The elevator still has to be set to >deflect up 30 degrees and down 20 degrees but the gearing is changed to give >the elevator more mechanical advantage over the stick, increasing stick >pressure. ... >Micheal Mims Vaughan Askue has some good words on this topic. (Freely rendered...) If stick force per G or per Speed change is low AND stick deflection per G or per speed change is low it is BETTER to make the stick FORCE acceptable because pilots are less sensitive to small displacements than to small forces. (And that's what Mr M is proposing.) Askue also opines: An (anti) servo tab can tailor many elevators to the desired stick force and deflection requirement. (To which I'm forced to add - a sloppy fitted antiservo tab is a great way to induce flutter ho, hum...) Regards brian whatcott Altus OK ------------------------------ Date: Wed, 25 Jun 1997 22:12:39 -0400 (EDT) From: DC4FREE@aol.com Subject: Re: KR: EAA Northwest Fly-in, Arlington, WA. In a message dated 97-06-25 09:40:49 EDT, you write: << Real, live KRs in Arlington...I'll be there. Sat. or Sunday for a gathering is fine with me. Paul M. Ashland, OR >> We don't know if any KR drivers will bring their toys up -- last year I remember only 1 KR at the flyin and it was on a truck and without a top. So like the carnival man says "you pays yo money and takes yor chances." But last year was MEGA FUN anyway!!!!! And the chance to get to know all the other builders working on or finished with is a treat. Don Wright Everett, WA ------------------------------ Date: Wed, 25 Jun 1997 22:19:46 -0400 (EDT) From: DC4FREE@aol.com Subject: Re: KR: EAA Northwest Fly-in, Arlington, WA. EAA Northwest Fly-in, Arlington, WA. Lets all meet Sunday 0900 at the firepit in front of the cafe at the north end of the ultralight hangers. Don Wright Everett, WA ------------------------------ Date: Mon, 23 Jun 1997 09:00:40 -0500 From: "Rick Hanson" Subject: Re: KR: KR longitudinal stability Tom, did you ever live in Biloxi MS. - ---------- > From: LVav8r@aol.com > To: krnet-l@teleport.com > Subject: Re: KR: KR longitudinal stability > Date: Wednesday, June 25, 1997 1:06 AM > > In a message dated 97-06-25 00:42:30 EDT, you write: > > << > smithr wrote: > > > > Micheal Mims wrote: > > The elevator control is just simply too light! Here are some > > > of the changes I have made to hopefully help sensitivity and stability: > > > > > > 1) Increase horizontal span 5 inches (2.5 each side) > > > 2) Tapered horizontal to a 1 inch airfoil section rather than 1/2 inch > sq. > > > 3) Drilled cable attach holes one inch closer to center on elevator > belcrank > > > 4) Will only use 15 to 30% of airfoil for CG range > > > 5) Considering adding strakes after more research on their effectiveness > per > > > square foot. (its not a 1 for 1 trade from what I understand) > > > > > > > On above point #3: This sounds good for increasing stick force > > (desirable) but in physics you don't get something for nothing. It will > > also yield more degrees of elevator deflection per inch of stick > > movement. This might not be good if you are trying to reduce pitchiness. > > The KR needs both more stick force and (slightly) more stick movement > > per deg of elevator deflection. I don't know what will give both. > > Possibly a non-linear cam. > > > > Bob Smith, Albany, NY > Hi Bob, > After digesting all the information available as to kr2 sensetivity > pitch and bank control I'v come to the conclusion that stops will have > to be installed to prevent over controling of the ailerons and vertical > stab.. The horizontal stab. control should be desensitized by allowing > more stick travel. I plan to tame my kr2 by adding 2' shoulders back, > adding 6" @ the enjine mount, 40" wide inside at the shoulders, 2' to > the main spars allowing 1' more for each flap. Thank you for your > opinion. > Gene Gargasz Elyria Ohio > >> > I have only limited experience flying homebuilts. The total time I have > logged is 1.8 hours and only in an RV-6A. That experience led me to believe > that stick force may be what most people are referring to when they talk > about sensitivity or longitudinal stability. The RV required very little > stick movement in either roll or pitch to accomplish the desired change in > attitude. The stick force however made it no problem to limit the controll > input. Does anyone on the list have any experience flying both the RV and the > KR to make a more objective observation on this? An engineer friend of > Jeanette Rand at S&F this year mentioned the stick force problem and > suggested a spring system to add it to the elevator controlls. I later flew > the RV and felt that without the level of stick force it had, that it would > be very easy to over-controll it also. I plan to fly my KR-2S first without > any added stick force to see what is the situation and then if necessary add > the spring system, unless someone with first hand experience can convince me > otherwise. So far that has yet to happen. A longer stick would also help. I > am still satisfied with my decision to build the KR-2S. I hope to get the > chance to fly a couple of KR's at the gathering so that I can make a more > educated observation on this matter. > Although there is an abundance of excellent information on this list I > must aplogize for not taking everyones ideas as gospel. There seems to be a > fair amount of speculation, and that is not necessesarily all bad. I just > recomend that you take anything you read regardless of the source with a > grain of salt. The people on this list that I put the most confidence in the > accuracy of their posts are the people who are already flying. After all the > FAA says that the pilot in command is the one who must determine that a > flight is conducted safely. > > Tom Kilgore > Las Vegas, NV > LVav8r@aol.com > KR-2S 2% complete > Private Pilot w/instrument & 260 hrs TT ------------------------------ Date: Wed, 25 Jun 1997 22:26:01 -0400 (EDT) From: Dennis Ambrose Subject: Re: KR: KR longitudinal stability At 01:59 PM 6/25/97 -0700, you wrote: >At 02:04 PM 6/25/97 -0500, you wrote: >>On Wed, 25 Jun 1997, smithr wrote: >> >>> Micheal Mims wrote: >>> >>> I am not sure springs would give you the "feel" you would want though, >>> but then again maybe they would?!? >>> >> >>I like everything I have read about stabilators with anti-servo tabs. >>For the same area you get a little more stability plus you can tailor the >>stick feel with the anti-servo tab gearing. >> > >I just re-read some material in the book called "Flight Testing Homebuilt >Aircraft" and he says to decrease control sensitivity decrease the control >arm (move the control cables/ pushrod closer to the pivot point). I have >read about Neico <-spelling? (Lancair) Aviation telling owners of certain >models or the Lancair (early ones) to do the same, their AD said to move the >pushrod 1 inch closer to the pivot. After a short discussion with my friend >Brad, he decided to try it on his Dragonfly and he loves the results! I >wish I could convince someone with a flying KR to give this a try!!! > >________________________________ >~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ >Micheal Mims >Just Plane Nutts >mailto:mimsmand@ix.netcom.com > >http://www.netcom.com/~mimsmand > Was this closer to the pivot point at the stick or the elevator. Dennis in Toronto,Canada ------------------------------ Date: Wed, 25 Jun 1997 22:25:59 -0400 (EDT) From: Dennis Ambrose Subject: Re: KR: KR longitudinal stability At 02:44 PM 6/24/97 -0400, you wrote: >Micheal Mims wrote: > The elevator control is just simply too light! Here are some >> of the changes I have made to hopefully help sensitivity and stability: >> >> 1) Increase horizontal span 5 inches (2.5 each side) >> 2) Tapered horizontal to a 1 inch airfoil section rather than 1/2 inch sq. >> 3) Drilled cable attach holes one inch closer to center on elevator belcrank >> 4) Will only use 15 to 30% of airfoil for CG range >> 5) Considering adding strakes after more research on their effectiveness per >> square foot. (its not a 1 for 1 trade from what I understand) >> > >On above point #3: This sounds good for increasing stick force >(desirable) but in physics you don't get something for nothing. It will >also yield more degrees of elevator deflection per inch of stick >movement. This might not be good if you are trying to reduce pitchiness. > The KR needs both more stick force and (slightly) more stick movement >per deg of elevator deflection. I don't know what will give both. >Possibly a non-linear cam. > >Bob Smith, Albany, NY > I agree with Bob, How does increasing the RATIO reduce over-driving the control surface? Yes it will increase forces by moving the elevator further than it normally would, per inch of stick travel, and thus increase feel(force required or load on stick) but I see this as adding to the overconrtol (pitchiness) problem. I am no engineer, but I see the most effective solution to be INCREASING the stick travel for each degree of elevator movement and increasing the stick forces (feel) through the use of a servo tab that has the required geometry to increase stick forces as the elevator is deflected. (Move the elevator on a Katana DA20 and watch the trim tab - if you have one at your field--- or go to Oskosh and see one!) The trim tab automatically deflects MORE than the elevator to increase FEEL. You can see the arrangement on page 84 of "Flight Testing Homebuilt Aircraft". Strakes are also on the agenda as they won't hurt and will only help. If I am wrong on any of these ideas, I hope someone with the PROPER knowledge and exp. will correct me. Regards Dennis Ambrose in TORONTO, CANADA ------------------------------ Date: Mon, 23 Jun 1997 09:17:40 -0500 From: "Rick Hanson" Subject: Re: KR: KR longitudinal stability The Mass Balance I suggested was a bad idea. I should have thought more about it before I suggested it. The mass balance is used in a lot of high performantenance aircraft to counter the effects of the acceleration and deacceleration on the control stick and linkage in the longitudinal control system. Properly configured, it negates the acceleration and deacceleration forces the pilot would feel through the control stick. - ---------- > From: Donald Reid > To: krnet-l@teleport.com > Subject: Re: KR: KR longitudinal stability > Date: Monday, June 23, 1997 8:33 PM > > Ted & Louisa Jones wrote: > > > > Don, please help me out here: I have been under the impression that mass > > balance in a control surface was used to inhibit flutter by adding > > weight forward of the hinge to equalize the weight of the control > > surface forward and aft of the hinge -- or approach equal weights. > > If my assumption is correct, the > > effect of mass balancing would have no affect on sensativity -- or > > minimal affect. > > > > However, if surface area of an elevator, for example, is added forward > > of the hinge line, this would most decidedly lighten the load in the > > control system while having a minimal affect on flutter unless that > > portion forward also incorporated weights to improve mass balance. > > > > What am I missing? > > > > Ted Jones > > The mass balance does decrease the chances of flutter. My understanding > of the mechanics is because the mass balance will change the natural > frequency of vibration. This is outside of anything I really know about. > I can't give a good explaination, so I won't try. > > As to sensativity: > When the unbalanced elevator is displaced out of the streamline position, > there will be a force created that is proportional to the displacement, > the area of the control surface, and the square of the air velocity. This > is the force that you feel in your hand and arm. If you go trailing edge > up, the air load tries to push it back to the streamlined position. You > have to maintain a back pressure on the stick to hold the elevator in > position. > > The control system design guys talk about stick force / G. They mean the > number of pounds of force you have to hold to create an extra 1G of > loading. If this is a low number, a gentle pull on the stick can > overstress the airframe and kill you. On the otherhand, it will feel like > a fighter aircraft, you think about a change and it happens. > > With a balanced elevator, the same displacement will produce approximately > the same force. (It will be a little bit less since the balance mass is > in front of the hinge line and will create a counteracting air load) If > the elevator is displaced trailing edge up, the mass balance will > counteract by trying to pull the trailing edge back down. This subtracts > out from the force that you must generate in your hand and arm. You end > up with a lower stick force per G loading and this means a more sensative > control system. > > I hope this explaination is helpful. > -- > Don Reid > donreid@erols.com ------------------------------ Date: Wed, 25 Jun 1997 19:38:22 -0700 From: Micheal Mims Subject: Re: KR: KR longitudinal stability At 10:26 PM 6/25/97 -0400, you wrote: > Was this closer to the pivot point at the stick or the elevator. > > Dennis in Toronto,Canada > > Elevator _______________________ ~~~~~~~~~~~~~~~~~~~~~~ Micheal Mims Just Plane Nutts in Irvine Ca. mailto:mimsmand@ix.netcom.com http://www.netcom.com/~mimsmand ------------------------------ Date: Wed, 25 Jun 1997 20:52:45 -0700 From: Micheal Mims Subject: Re: KR: KR longitudinal stability At 10:25 PM 6/25/97 -0400, you wrote: If I am wrong on any of these ideas, I hope someone with the PROPER knowledge and exp. will correct me. > What would qualify as PROPER knowledge? How about been there done that or does that not count for anything any more? _______________________ ~~~~~~~~~~~~~~~~~~~~~~ Micheal Mims Just Plane Nutts in Irvine Ca. mailto:mimsmand@ix.netcom.com http://www.netcom.com/~mimsmand ------------------------------ Date: Thu, 26 Jun 1997 00:18:45 EDT From: jscott.pilot@juno.com (Jeffrey E. Scott) Subject: KR: Non-Flying Report Yesterday I added a trim wedge to the rudder. This morning I went to the airport to test the handling with the additional trim on the rudder. I taxied out to the flight line, did the runup, but couldn't get the right mag to run correctly. Every time I switched to the right mag, the #3 EGT would take a dive, so it was obvious that I had a problem with the right mag #3 spark plug. While taxiing back to the my hanger I was paying more attention to the ignition problem than the wing tips and scraped the bottom of one wing tip on some debris my next door neighbor had thrown out in front of his hanger while reroofing it. :o( Just a small scrape that should polish out, but I wasn't very happy about it. This evening, I went back to the airport to see what was causing th ignition problem. What I found was that the lead wire had pulled out of the clip lead on one of my two unshielded plugs. My fault as I had put it together. After resoldering the joint, I was ready to go again. Thought I would go ahead and test the rudder trim this evening since the engine checked out OK now. Did my usual preflight and runup, taxied out to the runway, turned down the runway and added power. After covering 2000 feet of runway, the plane didn't seem to be accelerating properly, so I decided to abort the takeoff and cut the power and got onto the binders to get slowed back down. Once I got back down to taxi speed, I turned around and started to taxi back but it seemed that the plane would hardly move. I stopped, shut down the engine and found that the brakes were severely binding. I let it cool for a few minutes, then after the plane would roll, taxied back to the hanger. At the hanger, the brakes were hot enough again that the plane was difficult to roll back into the hanger. I opened up the bleeders on both brakes which relieved the pressure and rolled the plane back into the hanger. 1. Flight testing is more than just flying the airplane and recording numbers. 2. Any ideas what might be causing this problem with the brakes? 3. Some days it you're better off to stay in bed. Jeff Scott Los Alamos, NM - ---- Jeffrey Scott jscott.pilot@juno.com See construction of KR-2S N1213W at http://fly.hiwaay.net/~langford/kjeffs.html - ---- ------------------------------ End of krnet-l-digest V1 #50 ****************************