Date
1 - 20 of 38
Taxiing before first flight. (long editorial)
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Bob Farnam <bfarnam@...>
Larry,
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I see what you are talking about. Next step would be a paper doll sim of the action as David suggested. I'm not sure the rudder response should be "exponential", maybe only the tailwheel steering response. Bob F. -----Original Message-----
From: Q-LIST@... [mailto:Q-LIST@...]On Behalf Of Larry Hamm Sent: Friday, October 20, 2006 10:14 PM To: Q-LIST@... Subject: Re: [Q-LIST] Taxiing before first flight. (long editorial) Nope. Bob just wanted the sudden flash of insight, so I haven't gotten it down on paper yet. If I didn't describe it well enough, I'll do a sketch for now. Larry Hamm Steve wrote: > Hey Larry, Have you got a drawing of your bellcrank?? > > > Steve Ham > > > > -- Original Message ----- > From: Larry Hamm > To: Q-LIST@... > Sent: Friday, October 20, 2006 4:54 PM > Subject: Re: [Q-LIST] Taxiing before first flight. (long editorial) > > > Bob, > > Install a bellcrank a la the JB6, but with a twist. > > Fab a disk with a cable guide groove on the edge, sort of like an > automotive throttle advance on the side of a carb or throttle body. This > disk should be oval shaped, with the long axis pointed at the rudder. > The rudder cables are connected at the end closest to the cockpit, and > run down each side of the disk. This disk is attached to the top of the > bellcrank. As the bellcrank and disk turn, the rudder cables see an > increasing radius and turn the rudder faster. That will give you the > exponential response you're looking for, I believe. > > Clear as mud?? > > That's the "Hamm" mod to the JB6. (If it works!) > > Larry Hamm > > Bob Farnam wrote: > > >I would really like to have what the RC guys refer to as > > "exponential" control, where the response is low in the center part of the > > travel, but increases at full rudder input. Easy to do with an RC > > transmitter which has it builtin, but I haven't yet figured out a simple and > > durable mechanical way to make it happen. Anyone have a sudden flash of > > insight? > > > > Bob F > > EAA Flight Advisor > > > > > > > > > > Quickie Builders Association WEB site > http://www.quickiebuilders.org > > > Yahoo! Groups Links > > > > > > |
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quickieaircraft
I'm pretty sure a four-bar linkage would accomplish
your needs here. I'm a little leary about that many pivots in the system, though. Imraan UAV systems engineer and pilot in Washington DC Still looking for Q2/Q200 --- Paul Agnew <bluejet@...> wrote: Has anyone tried designing a cam bellcrank that __________________________________________________ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com |
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quickieaircraft
I'm pretty sure a four-bar linkage would accomplish
your needs here. I'm a little leary about that many pivots in the system, though. Imraan UAV systems engineer and pilot in Washington DC Still looking for Q2/Q200 --- Paul Agnew <bluejet@...> wrote: Has anyone tried designing a cam bellcrank that __________________________________________________ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com |
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Paul Agnew <bluejet@...>
Has anyone tried designing a cam bellcrank that would provide a non-linear
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response to pedal input? I know I've seen something like this before in an different application (possibly one of the helo's I used to fly), but it seems like it would address Bob's question. Paul Agnew Lurking Q-200 wannabe West Palm Beach, FL (Airbus driver in real life for a certain blue-themed airline.) -----Original Message-----
From: Q-LIST@... [mailto:Q-LIST@...] On Behalf Of Bob Farnam Sent: Friday, October 20, 2006 1:08 PM To: Q-LIST@... Subject: RE: [Q-LIST] Taxiing before first flight. (long editorial) My ratio is not as much as I would like, but is limited by my own requirement that I be able to reach the unlock detent on the full swivelling tailwheel at full rudder. This so I can pivot around a wheel on the ground. The result is that my airplane is less sensitive than the original design - enough that I can fairly easily steer it straight at takeoff speed, but still sensitive. I would really like to have what the RC guys refer to as "exponential" control, where the response is low in the center part of the travel, but increases at full rudder input. Easy to do with an RC transmitter which has it builtin, but I haven't yet figured out a simple and durable mechanical way to make it happen. Anyone have a sudden flash of insight? Bob F EAA Flight Advisor |
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Larry Hamm <LDHAMM@...>
Nope. Bob just wanted the sudden flash of insight, so I haven't gotten it down on paper yet. If I didn't describe it well enough, I'll do a sketch for now.
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Larry Hamm Steve wrote: Hey Larry, Have you got a drawing of your bellcrank?? |
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bfarnam@...
Mike,
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My tailwheel does move a little bit short of detent unlock and I get unlock by stabbing the brake on the side I'm turning to after I get full rudder. The springs give enough to let it unlock. I think Mark Summers did some machining on his tailwheel to change the detent position although I haven't seen it apart. Would be worth looking at and it probably wouldn't be too hard to do. Don't know about Aviation Products. They might be willing. I'll take a closer look at the assembly when I do my annual. Bob F. ----- Original Message ----
From: Mike Perry <dmperry1012@...> To: Q-LIST@... Sent: Friday, October 20, 2006 7:08:49 PM Subject: RE: [Q-LIST] Taxiing before first flight. (long editorial) Bob: I remember you saying that the unlock detent matched full rudder deflection, but I don't remember exactly why. Suppose the tailwheel unlock required 10 degrees more than full rudder. Couldn't you reach unlock by going to full rudder then differential braking? Some skidding I suppose, but wouldn't that be worth it if the plane was easier to control during takeoff and landing? Alternately, could we change the detent position? Would the folks at Aviation Products Inc. do a special run? For anyone who wonders I have flown with Bob and his plane tracks very well! Mike Perry At 10:08 AM 10/20/2006 -0700, you wrote: My ratio is not as much as I would like, but is limited by my own |
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Mike Perry <dmperry1012@...>
Bob:
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I remember you saying that the unlock detent matched full rudder deflection, but I don't remember exactly why. Suppose the tailwheel unlock required 10 degrees more than full rudder. Couldn't you reach unlock by going to full rudder then differential braking? Some skidding I suppose, but wouldn't that be worth it if the plane was easier to control during takeoff and landing? Alternately, could we change the detent position? Would the folks at Aviation Products Inc. do a special run? For anyone who wonders I have flown with Bob and his plane tracks very well! Mike Perry At 10:08 AM 10/20/2006 -0700, you wrote:
My ratio is not as much as I would like, but is limited by my own |
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Mike Perry <dmperry1012@...>
Thanks Dave for the WW II fighter info -- I knew I read it somewhere but
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couldn't locate it last nite. I also vaguely remember something about a tail dragger with only 5 deg of pivot before the tail wheel released. Out of curiosity, what do you think would happen if we didn't have a steerable tailwheel, and used differential brakes only for ground steering? Maybe with a larger rudder? Plane would be a lot less likely to swerve on the runway. Mike Perry At 11:27 PM 10/19/2006 -0700, you wrote:
Mike, |
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Steve <sham@...>
Hey Larry, Have you got a drawing of your bellcrank??
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Steve Ham -- Original Message -----
From: Larry Hamm To: Q-LIST@... Sent: Friday, October 20, 2006 4:54 PM Subject: Re: [Q-LIST] Taxiing before first flight. (long editorial) Bob, Install a bellcrank a la the JB6, but with a twist. Fab a disk with a cable guide groove on the edge, sort of like an automotive throttle advance on the side of a carb or throttle body. This disk should be oval shaped, with the long axis pointed at the rudder. The rudder cables are connected at the end closest to the cockpit, and run down each side of the disk. This disk is attached to the top of the bellcrank. As the bellcrank and disk turn, the rudder cables see an increasing radius and turn the rudder faster. That will give you the exponential response you're looking for, I believe. Clear as mud?? That's the "Hamm" mod to the JB6. (If it works!) Larry Hamm Bob Farnam wrote: >I would really like to have what the RC guys refer to as > "exponential" control, where the response is low in the center part of the > travel, but increases at full rudder input. Easy to do with an RC > transmitter which has it builtin, but I haven't yet figured out a simple and > durable mechanical way to make it happen. Anyone have a sudden flash of > insight? > > Bob F > EAA Flight Advisor |
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Allan Farr <afarr@...>
Hi Jim
That helps clear it up. I had always thought a locking tailwheel (& a grippy tyre) would help, it's the first time I have read or realized that someone is using one. AF Allan, Reread my comment. I didn't like the idea of loosing control and not being able to get back to center line way before I installed the brakes. This was obviously the opinion of a lot of others as well and today you see the results. QAC designed a pretty rudimentary airplane. Cheap was a word that was in their vocabulary. Further as David pointed out, we discovered a long time ago that keeping the tailwheel straight as possible on take off or landing was a must in a Q. If you could prevent twitchyness you had much better control. Tailwheel/rudder differential via the bellcrank with internal springs to the tail wheel to absorb side loads and Air Products locking tail wheel did the trick. The new locking/swiveling tailwheel has a 6" bellcrank and the stock rudder has a 3" bellcrank. We simply installed an additional 6" bellcrank behind the FS120 bulkhead. The tailwheel cables attach to the internal bellcrank at 6" (same width as tailwheel bell crank) via springs and the rudder cables attached to the internal bellcrank at 3-4" (same as rudder bellcrank) from rudder to internal bellcrank. Thus a desensitized tailwheel/rudder with proportionally more rudder travel for a given tail wheel input. Hope this clears it up and why the bellcrank/tailwheel combo is a valuable asset on this airplane. Add Gall Alignment and toe brake mod and you have a stable airplane. Regards, Jim Patillo |
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Ron Triano <rondefly@...>
You are right Bob, thanks for the correction. That is the idea though.
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Ron Triano N91RT Sonerai IIs, is a bird, it really flies Q200, Back working on it, soon to be flying -----Original Message-----
From: Q-LIST@... [mailto:Q-LIST@...] On Behalf Of Bob Farnam Sent: Friday, October 20, 2006 11:09 AM To: Q-LIST@... Subject: RE: [Q-LIST] Re: Taxiing before first flight. (long editorial) Just backwards, Ron. If you want less angular movement of the tailwheel, you should use a big (long) belcrank on the tailwheel, not a short one. Bob F. -----Original Message----- From: Q-LIST@yahoogroups. <mailto:Q-LIST%40yahoogroups.com> com [mailto:Q-LIST@yahoogroups. <mailto:Q-LIST%40yahoogroups.com> com]On Behalf Of Ron Triano Sent: Friday, October 20, 2006 6:22 AM To: Q-LIST@yahoogroups. <mailto:Q-LIST%40yahoogroups.com> com Subject: RE: [Q-LIST] Re: Taxiing before first flight. (long editorial) Allen, whichever rudder/tailwheel system you choose to use you can get the same results if you want to change the angle of the tailwheel. Just think of the tailwheel as a gear with a chain to another gear. Small to big or big to small, If you want less movement at the tailwheel just move the attach holes on the tailwheel bellcrank closer to the center. In other words, big rudder bellcrank small tailwheel bellcrank will let the tailwheel travel less. I presently am flying my Sonerai which also is very twitchy. But the difference between the two is the Sonerai tail is lifted shortly after power applied and you are steering with the rudder only. Most take the Q off in 3 point attitude. The main point I am trying to get across is to study each system, many work just fine. I never like being a Sheep and following the whole pack. These are Experimental aircraft, so try things only after much study and don't be shy to say I was wrong. Ron Triano South Lake Tahoe, CA The Sonerai is finished and flying finishing the Q200 -----Original Message----- From: Q-LIST@yahoogroups. <mailto:Q-LIST%40yahoogroups.com> com [mailto:Q-LIST@yahoogroups. <mailto:Q-LIST%40yahoogroups.com> com] On Behalf Of Jim Patillo Sent: Friday, October 20, 2006 4:15 AM To: Q-LIST@yahoogroups. <mailto:Q-LIST%40yahoogroups.com> com Subject: [Q-LIST] Re: Taxiing before first flight. (long editorial) Allan, Reread my comment. I didn't like the idea of loosing control and not being able to get back to center line way before I installed the brakes. This was obviously the opinion of a lot of others as well and today you see the results. QAC designed a pretty rudimentary airplane. Cheap was a word that was in their vocabulary. Further as David pointed out, we discovered a long time ago that keeping the tailwheel straight as possible on take off or landing was a must in a Q. If you could prevent twitchyness you had much better control. Tailwheel/rudder differential via the bellcrank with internal springs to the tail wheel to absorb side loads and Air Products locking tail wheel did the trick. The new locking/swiveling tailwheel has a 6" bellcrank and the stock rudder has a 3" bellcrank. We simply installed an additional 6" bellcrank behind the FS120 bulkhead. The tailwheel cables attach to the internal bellcrank at 6" (same width as tailwheel bell crank) via springs and the rudder cables attached to the internal bellcrank at 3-4" (same as rudder bellcrank) from rudder to internal bellcrank. Thus a desensitized tailwheel/rudder with proportionally more rudder travel for a given tail wheel input. Hope this clears it up and why the bellcrank/tailwheel combo is a valuable asset on this airplane. Add Gall Alignment and toe brake mod and you have a stable airplane. Regards, Jim Patillo --- In Q-LIST@yahoogroups. <mailto:Q-LIST%40yahoogroups.com> com, "Allan Farr" <afarr@...> wrote: lever unacceptable, do you mean from experience or just the thought of it? I'm not getting at anything, I'm just interested because QAC obviously thought the opposite. RegardsFarr" <afarr@> wrote: brake& that QAC changed it to a single pull lever. Was their reasoning brakes somodification is a hell of a lot easier than installing toe needmany of us (Texas contingent)did finger brakes and got use to it. flights.three hands to perform this operation safely. Problem is I haven't reallyHe was really creative in comming up with a unique differential hourseasy. Leave the plane like it is and go fly! "Daveon them, fine. P.S. They are also really good Q pilots. Has either Richardson" <dave@> wrote: threebetter hands to make it work safely. I hope Wes listens to you andrealizesyou are not just pontificating. Have you let him taxi your planetoshow him what he could be experiencing as compared to what his isup |
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Larry Hamm <LDHAMM@...>
Bob,
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Install a bellcrank a la the JB6, but with a twist. Fab a disk with a cable guide groove on the edge, sort of like an automotive throttle advance on the side of a carb or throttle body. This disk should be oval shaped, with the long axis pointed at the rudder. The rudder cables are connected at the end closest to the cockpit, and run down each side of the disk. This disk is attached to the top of the bellcrank. As the bellcrank and disk turn, the rudder cables see an increasing radius and turn the rudder faster. That will give you the exponential response you're looking for, I believe. Clear as mud?? That's the "Hamm" mod to the JB6. (If it works!) Larry Hamm Bob Farnam wrote: I would really like to have what the RC guys refer to as |
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David J. Gall
...Took the words right out of my keyboard...!
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(No wonder the Sonerai is twitchy...????) :) David J. Gall -----Original Message----- |
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Bob Farnam <bfarnam@...>
Just backwards, Ron. If you want less angular movement of the tailwheel, you
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should use a big (long) belcrank on the tailwheel, not a short one. Bob F. -----Original Message-----
From: Q-LIST@... [mailto:Q-LIST@...]On Behalf Of Ron Triano Sent: Friday, October 20, 2006 6:22 AM To: Q-LIST@... Subject: RE: [Q-LIST] Re: Taxiing before first flight. (long editorial) Allen, whichever rudder/tailwheel system you choose to use you can get the same results if you want to change the angle of the tailwheel. Just think of the tailwheel as a gear with a chain to another gear. Small to big or big to small, If you want less movement at the tailwheel just move the attach holes on the tailwheel bellcrank closer to the center. In other words, big rudder bellcrank small tailwheel bellcrank will let the tailwheel travel less. I presently am flying my Sonerai which also is very twitchy. But the difference between the two is the Sonerai tail is lifted shortly after power applied and you are steering with the rudder only. Most take the Q off in 3 point attitude. The main point I am trying to get across is to study each system, many work just fine. I never like being a Sheep and following the whole pack. These are Experimental aircraft, so try things only after much study and don't be shy to say I was wrong. Ron Triano South Lake Tahoe, CA The Sonerai is finished and flying finishing the Q200 -----Original Message----- From: Q-LIST@... [mailto:Q-LIST@...] On Behalf Of Jim Patillo Sent: Friday, October 20, 2006 4:15 AM To: Q-LIST@... Subject: [Q-LIST] Re: Taxiing before first flight. (long editorial) Allan, Reread my comment. I didn't like the idea of loosing control and not being able to get back to center line way before I installed the brakes. This was obviously the opinion of a lot of others as well and today you see the results. QAC designed a pretty rudimentary airplane. Cheap was a word that was in their vocabulary. Further as David pointed out, we discovered a long time ago that keeping the tailwheel straight as possible on take off or landing was a must in a Q. If you could prevent twitchyness you had much better control. Tailwheel/rudder differential via the bellcrank with internal springs to the tail wheel to absorb side loads and Air Products locking tail wheel did the trick. The new locking/swiveling tailwheel has a 6" bellcrank and the stock rudder has a 3" bellcrank. We simply installed an additional 6" bellcrank behind the FS120 bulkhead. The tailwheel cables attach to the internal bellcrank at 6" (same width as tailwheel bell crank) via springs and the rudder cables attached to the internal bellcrank at 3-4" (same as rudder bellcrank) from rudder to internal bellcrank. Thus a desensitized tailwheel/rudder with proportionally more rudder travel for a given tail wheel input. Hope this clears it up and why the bellcrank/tailwheel combo is a valuable asset on this airplane. Add Gall Alignment and toe brake mod and you have a stable airplane. Regards, Jim Patillo --- In Q-LIST@yahoogroups. <mailto:Q-LIST%40yahoogroups.com> com, "Allan Farr" <afarr@...> wrote: > > Thanks for that Jim. When you say that you found the single pull lever unacceptable, do you mean from experience or just the thought of it? I'm not getting at anything, I'm just interested because QAC obviously thought the opposite. > Regards > Allan F > > ----- Original Message ----- > From: Jim Patillo > To: Q-LIST@yahoogroups. <mailto:Q-LIST%40yahoogroups.com> com > Sent: Friday, 20 October 2006 15:22 > Subject: [Q-LIST] Re: Taxiing before first flight. (long editorial) > > > > Allan, > > I bought my Quickie Kit in October 1981 from the factory. It had a > single pull lever that when applied set both brakes. I found this to > be totally unacceptable in any kind of crosswind. I did not like the > idea but toyed with dual finger brakes not near as close to fininshing > as Bob Malachek, Sam Hoskins, Paul Fisher and Tom Moore. So I delayed > finishing the brakes knowing some how I was going to install toe > brakes. Then I met Bob Farnam and he showed me the fix. Bob had > already designed and installed toe brakes so I basically copied his > set up. Our toe brake pedal geometry varied a little but both planes > handled basically the same....................tame. I didn't do > David's alignment becaue the plane was already a "pussycat" . I know > for a fact from Sam and others that the alignment worked wonders on > many planes. > > Later Brad Olson, Jeff Rudledge and Mark Summers installed toe brakes > with small variations but basically the same. I can say............ > tame my good buddy Sam because it's so. > > Now should we collabrate and make a Q that can kick Klaus' ass? > > Regards, > > JP > > --- In Q-LIST@yahoogroups. <mailto:Q-LIST%40yahoogroups.com> com, "Allan Farr" <afarr@> wrote: > > > > Hi Jim. I understand that originally the Q2 had differential brakes, > & that QAC changed it to a single pull lever. Was their reasoning > faulty in your opinion? > > Regards > > Allan Farr > > Q2 > > > > ----- Original Message ----- > > From: Jim Patillo > > To: Q-LIST@yahoogroups. <mailto:Q-LIST%40yahoogroups.com> com > > Sent: Friday, 20 October 2006 11:28 > > Subject: [Q-LIST] Re: Taxiing before first flight. (long editorial) > > > > > > > > Dave, > > > > I hear you loud and clear and it's not that we had a better idea or > > that I'm pontificating. The entire tail dragger world had a better > > idea. Why don't you see finger brakes on all those tail draggers? > > Why do you think finger brakes even came into existance in the Q > > world? It was because we realized a single pull hand brake was not > > the answer and we needed dual differentiating brakes. A finger brake > > modification is a hell of a lot easier than installing toe brakes so > > many of us (Texas contingent)did finger brakes and got use to it. > > > > I'm simply stating what I saw and did. As you point out, you do need > > three hands to perform this operation safely. Problem is I haven't > > run across any three handed pilots lately. > > > > If people want to do things different, thats their perogative. As I > > said before, the post was not to denigrate or pupu Wes's idea or > > approach but to help prevent crashes before or during first flights. > > He was really creative in comming up with a unique differential > > finger brake, problem is it doesn't work and its almost counter > > intuitive. The control is to seensitive when moving the stick left > > to right or visa versa. Having taxied his plane, it just takes so > > much more to deal with than toe brakes. He can prove this out really > > easy. Leave the plane like it is and go fly! > > > > I know Paul and Sam have finger brakes and have lots of proven hours > > on them, fine. P.S. They are also really good Q pilots. Has either > > one of them ever had to repair their planes due to a mishap on the > > runway/taxiway or are their planes totally tame? > > > > Many people on this list know what I'm talking about but just don't > > care to express it. > > > > Regards, > > > > JP > > > > --- In Q-LIST@yahoogroups. <mailto:Q-LIST%40yahoogroups.com> com, "Dave Richardson" <dave@> wrote: > > > > > > You know Jim, it is easy to get so wrapped up in the "I've got a > > better > > > idea" mode that all other solutions become just noise. It sounds > > like > > > Wes came up with a neat adaptation of the original single pull > > lever. > > > Your practical experience shows, though, he would really need three > > > hands to make it work safely. I hope Wes listens to you and > > realizes > > > you are not just pontificating. Have you let him taxi your plane > > to > > > show him what he could be experiencing as compared to what his is > > > getting out of his design? I'll bet he spent far more time coming > > up > > > with his solutions and implementing them than it would take to > > install > > > the proven six pack. > > > > > > I had something similar happen to me with my reflexor prior to > > first > > > flight when a major flaw in my design was pointed out. Rather than > > > argue my position, I ripped out the whole mechanisim I worked > > pretty > > > hard on designing and implementing and installed a Falkner > > reflexor in a > > > fraction of the time. I have a much safer reflexor as a result > > and that > > > is what really counts. > > > > > > To Wes and other guys like Wes, why waste your time, energy and > > $'s on > > > something that has already been solved and proven to be > > successful? Do > > > what works and go fly your plane. > > > > > > Dave Richardson > > > Tri-Q2 N825DR 84 hrs. > > > > > > > > > -----Original Message----- > > > From: Jim Patillo > > > Sent: Thu 10/19/2006 2:33 PM > > > To: Q-LIST@yahoogroups. <mailto:Q-LIST%40yahoogroups.com> com > > > Cc: > > > Subject: [Q-LIST] Taxiing before first flight. (long editorial) > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > |
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Bob Farnam <bfarnam@...>
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-----Original Message-----
From: Q-LIST@... [mailto:Q-LIST@...]On Behalf Of Sam Hoskins Sent: Thursday, October 19, 2006 4:43 PM To: Q-LIST@... Subject: RE: [Q-LIST] Taxiing before first flight. (long editorial) My two cents worth, where I disagree with my good friend, Jim. 1. I do use differential finger brakes, with great success. They are positioned right behind the throttle. I let go of the throttle to use the brakes. You can see my installation here: http://home.mchsi.com/~shoskins/brakes01.jpg 2. I do have rudder splitters. See the installation here: http://home.mchsi.com/%7Eshoskins/aircraftdetail/tailcone01.jpg Each cable, splitting off to the rudder bellcrank, has a turnbuckle for adjustment. 3. I do not have the intermediate bellcrank. [Bob Farnam] I still don't like the cable split without the belcrank, because it puts most of the rudder pedal load on the lower rudder bearing. That load can be quite high. It's OK IF you don't lean on the rudder pedals (I sometimes do during stressful moments) and if the lower rudder bearing is up to it. It isn't very stout in the original. [Bob Farnam] Bob F. I believe the single biggest ground handling improvement that can be made is correcting the wheel alignment, per Gall. I made a blog entry about it: http://samhoskins.blogspot.com/ Having said that, I think it's fine for people to install the 6-pack. A couple of years ago I had the opportunity to taxi Jim's plane. I thought it felt a lot like mine, though maybe a little "softer" on the rudder pedals due to the tail wheel cable springs. (I bought a set, but never got around to installing them). Jim's point is well taken, if you build like a successful model, you should have the same results as that plane. However, "tame" is a word that is not in my Quickie vocabularly. Sam Hoskins Murpysburger, IL _____ From: Q-LIST@... [mailto:Q-LIST@...] On Behalf Of Jim Patillo Sent: Thursday, October 19, 2006 1:33 PM To: Q-LIST@... Subject: [Q-LIST] Taxiing before first flight. (long editorial) Fellas, I had the opportunity to high speed taxi Wes Isbergs' Q200 Saturday before his first flight and would like to share some info. Even though he did a fair job of controlling the plane down the runway, I found it very difficult to handle. I could not keep it straight either with rudder or his braking system or the combination. Wind was about 12K - 10-15 degrees off the nose. (Note: he has no bellcrank but has split the cables internally to rudder and tail wheel and has a modified dual differential finger brake system). Guess he didn't buy the Jim/Bob Six Pack Mod concept. My immediate response to him was to park the plane before he got hurt and fix the problem! Now for the details. With just splitting the cables, Wes has no way to differentiate (detune)the angle of the tail wheel from the rudder. He's installed a modified dual finger brake that has a single stick that slides sideways to apply pressure to one master cylinder or the other or both. That is not good because its way to sensitive and hard to get positive results from known inputs. Further exacerabating the situation is his hand is on the brake and not the throttle when taking off or landing. Not a good thing! How many serious tail draggers have anything other than toe brakes or heel brakes? Its just not natural to have finger brakes on a tail dragger and is to dangerous in my opinion. There are way to many things going on to be doing this additional "dance". This leads me to a conclusion. The Q's with sixpack mods installed are really quite tame, ask anyone who has them. I cannot for the life of me understand why anyone would want to do anything different. Yet we see it all the time. Most new Q pilots have a very difficult time handling their planes initially and often crack them up or have an incident even before the first flight. Because you didn't invent it, doesn't mean you can't copy it! The situation with Wes; here's a very intellignet fella sitting on a field with sucessuful Q's all around, yet he chooses to do his own thing. Why? To much additional cost? To much additional labor? Doesn't have a clear undrstanding of the problem? Doesn't know how to fix it - NOT! What? I do not understand this. This leads me to another conclusion. If Wes, sitting in the middle of LVK with sucessful planes all aroud, chooses to go a different route, what does that tell you about builders working on their own, isolated and out of touch? I now understand why this is not so simple and brace yourself fellas, we're in for more! These comments are in no way intended to bring heat on Wes but to simply make a couple of points as to why Q pilots are still smacking up their planes. Hopefully this turns on the lights for someoen who don't want to get hurt. Regards, Jim Patillo N46JP Q200 800 hours in type. So far, even in severe crosswinds, this plane has never deviated from the center line. Bingo! There's a reason. |
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Bob Farnam <bfarnam@...>
My ratio is not as much as I would like, but is limited by my own
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requirement that I be able to reach the unlock detent on the full swivelling tailwheel at full rudder. This so I can pivot around a wheel on the ground. The result is that my airplane is less sensitive than the original design - enough that I can fairly easily steer it straight at takeoff speed, but still sensitive. I would really like to have what the RC guys refer to as "exponential" control, where the response is low in the center part of the travel, but increases at full rudder input. Easy to do with an RC transmitter which has it builtin, but I haven't yet figured out a simple and durable mechanical way to make it happen. Anyone have a sudden flash of insight? Bob F EAA Flight Advisor -----Original Message-----
From: Q-LIST@... [mailto:Q-LIST@...]On Behalf Of Allan Farr Sent: Friday, October 20, 2006 1:17 AM To: Q-LIST@... Subject: Re: [Q-LIST] Taxiing before first flight. (long editorial) I suggested a locking tailwheel about a year ago, but nobody seemed to think very much of the idea. Allan F ----- Original Message ----- From: David J. Gall To: Q-LIST@... Sent: Friday, 20 October 2006 19:27 Subject: RE: [Q-LIST] Taxiing before first flight. (long editorial) Mike, You are SOOOOO right! It bears repeating: > I would like to point out something I think people loose > sight of regarding the Jim-Bob 6-Pack: The bellcrank mod > allows the builder to reduce the pivot arc (travel) of the > tail wheel relative to the rudder travel. That makes the > plane much less susceptible to sudden swerves at high speed, > and thus easier to control during takeoff and landing. The > tail wheel springs also desensitize the tail wheel. Consider that a rudder can have twenty-five or more degrees of deflection before it stalls whereas a tailwheel will start to skid (analogous to airfoil stalling) at between three and seven degrees deflection depending on the type of tire. So you really NEED to have some ratio between the rudder deflection and the tailwheel deflection at any given rudder pedal deflection. A belcrank giving a 3:1 ratio of rudder to tailwheel deflection combined with some springs on the tailwheel to let it trail against load somewhat (giving an even higher effective ratio) might be about right to really desinsitize ("tame") the Q2, but you'd have to put up with a large turning radius at low speeds. Then, too, the ratios described above are mechanical ratios; there is a complicating aerodynamic component that I'm ignoring right now, due to the varying effectiveness of the rudder at varying airspeeds. What ratios are people using, Jim, Bob? Consider also that the main objective of the takeoff or landing run is to go STRAIGHT and you soon realize that the ideal place for the tailwheel is locked, dead straight. Many (most??) WWII fighters had locking tailwheels. The "reduced arc" you refer to, Mike, was essentially nil with directional control provided by rudder and differential brakes only. Of course, some steering capability must be available for low speed taxiing with the tailwheel unlocked.... David J. Gall > -----Original Message----- > From: Q-LIST@... [mailto:Q-LIST@...] > On Behalf Of Mike Perry > Sent: Thursday, October 19, 2006 8:30 PM > To: Q-LIST@... > Subject: Re: [Q-LIST] Taxiing before first flight. (long editorial) > > I would like to point out something I think people loose > sight of regarding the Jim-Bob 6-Pack: The bellcrank mod > allows the builder to reduce the pivot arc (travel) of the > tail wheel relative to the rudder travel. That makes the > plane much less susceptible to sudden swerves at high speed, > and thus easier to control during takeoff and landing. The > tail wheel springs also desensitize the tail wheel. > > (You could achieve the same thing using split cables and > changing the lengths of the control horns on the rudder and > tail wheel, but the bell crank is an easy place to change the > relative travel.) > > I understand the tail wheels of some WW II fighters had very > little travel, but I can't seem to document that right now. > My opinion is that tail draggers that land at high speeds > need tail wheels that are "desensitized" > with a reduced pivot arc and tail wheel springs. > > I understand the Q-2 plans from QAC used a tail wheel with a > wide pivot arc in order to negotiate tighter corners on > airports. This design worked OK on the Quickie, which lands > at a lower speed, but has been problematic on the Q-2 and > Q-200. The 6-Pack has full pivoting tail wheel and > differential brakes to allow you to negotiate tight corners, > and a reduced pivot arc and springs to desensitize the tail > wheel at high speeds. > > Jim, I think this is what you meant when you said: "With just > splitting the cables, Wes has no way to differentiate > (detune)the angle of the tail wheel from the rudder." I just > wanted to say it more clearly. > > Mike Perry > > At 06:33 PM 10/19/2006 +0000, Jim Patillo wrote: > > > >Fellas, > > > >I had the opportunity to high speed taxi Wes Isbergs' Q200 Saturday > >before his first flight and would like to share some info. > Even though > >he did a fair job of controlling the plane down the runway, > I found it > >very difficult to handle. I could not keep it straight either with > >rudder or his braking system or the combination. Wind was > about 12K - > >10-15 degrees off the nose. (Note: he has no bellcrank but has split > >the cables internally to rudder and tail wheel and has a > modified dual > >differential finger brake system). > >Guess he didn't buy the Jim/Bob Six Pack Mod concept. My immediate > >response to him was to park the plane before he got hurt and fix the > >problem! > > > >Now for the details. With just splitting the cables, Wes has > no way to > >differentiate (detune)the angle of the tail wheel from the > rudder. He's > >installed a modified dual finger brake that has a single stick that > >slides sideways to apply pressure to one master cylinder or > the other > >or both. That is not good because its way to sensitive and > hard to get > >positive results from known inputs. > >Further exacerabating the situation is his hand is on the > brake and not > >the throttle when taking off or landing. Not a good thing! How many > >serious tail draggers have anything other than toe brakes or heel > >brakes? Its just not natural to have finger brakes on a tail dragger > >and is to dangerous in my opinion. There are way to many > things going > >on to be doing this additional "dance". > > > >This leads me to a conclusion. The Q's with sixpack mods > installed are > >really quite tame, ask anyone who has them. I cannot for the > life of me > >understand why anyone would want to do anything different. > Yet we see > >it all the time. Most new Q pilots have a very difficult > time handling > >their planes initially and often crack them up or have an > incident even > >before the first flight. Because you didn't invent it, > doesn't mean you > >can't copy it! The situation with Wes; here's a very > intellignet fella > >sitting on a field with sucessuful Q's all around, yet he > chooses to do > >his own thing. Why? > >To much additional cost? To much additional labor? Doesn't > have a clear > >undrstanding of the problem? Doesn't know how to fix it - NOT! > >What? I do not understand this. > > > >This leads me to another conclusion. If Wes, sitting in the > middle of > >LVK with sucessful planes all aroud, chooses to go a > different route, > >what does that tell you about builders working on their own, > isolated > >and out of touch? I now understand why this is not so simple > and brace > >yourself fellas, we're in for more! > > > >These comments are in no way intended to bring heat on Wes but to > >simply make a couple of points as to why Q pilots are still > smacking up > >their planes. Hopefully this turns on the lights for someoen > who don't > >want to get hurt. > > > >Regards, > >Jim Patillo N46JP Q200 800 hours in type. So far, even in severe > >crosswinds, this plane has never deviated from the center line. > >Bingo! There's a reason. |
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Ron Triano <rondefly@...>
As I said Dave, something about sheep.
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Ron Triano South Lake Tahoe, CA The Sonerai is finished and flying finishing the Q200 -----Original Message-----
From: Q-LIST@... [mailto:Q-LIST@...] On Behalf Of Dave Richardson Sent: Friday, October 20, 2006 7:30 AM To: Q-LIST@... Subject: RE: [Q-LIST] Taxiing before first flight. (long editorial) Hi Ron, I might point out that your disagreements are based on your theoretical observations. The sixpack is based now on repeated experiences by several different pilots. The sixpack bellcrank deals with more issues than your setup with the different ratios being sent to the rudder and tailwheel. That's not to say your system won't work. Heck you could probably take a big stick with you in the cockpit and poke it through holes and drag it on the runway to give you differential braking. People can get used to most anything. I've always heard the best way to do something well is to find someone who is successful and do what they do. Dave Richardson -----Original Message----- From: Ron Triano Sent: Fri 10/20/2006 8:45 AM To: Q-LIST@yahoogroups. <mailto:Q-LIST%40yahoogroups.com> com Cc: Subject: RE: [Q-LIST] Taxiing before first flight. (long editorial) |
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Ron,
Klaus is using his own design and yes I'm sure he's turning hisprop in the 4,000 + RPM range. Dave Richardson is correct my friend. You are still therotical in your modifications until your plane is in the air. You may have solved the problem and you may not have. We'll find out shortly, won't we? Your comment about not being a "sheep" is interesting. That might just be some flawed logic there. Best regards, Jim P. P.S. Did you get that new headset ordered? --- In Q-LIST@..., "Ron Triano" <rondefly@...> wrote: Could he be turning the 4400+ like the formula 1s.?Behalf Of Jim Patillo"Dave Richardson" <dave@> wrote:better |
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Patrick Panzera <panzera@...>
I've always heard the best way to do something well is to find someoneIt may be the easiest way to an end, but not necessarily the best. If everyone followed this motto, we'd have no six-pack. For that matter, we'd have no tandem wing aircraft as well as no composite construction. Pat |
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Dave Richardson <dave@...>
Hi Ron,
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I might point out that your disagreements are based on your theoretical observations. The sixpack is based now on repeated experiences by several different pilots. The sixpack bellcrank deals with more issues than your setup with the different ratios being sent to the rudder and tailwheel. That's not to say your system won't work. Heck you could probably take a big stick with you in the cockpit and poke it through holes and drag it on the runway to give you differential braking. People can get used to most anything. I've always heard the best way to do something well is to find someone who is successful and do what they do. Dave Richardson -----Original Message-----
From: Ron Triano Sent: Fri 10/20/2006 8:45 AM To: Q-LIST@... Cc: Subject: RE: [Q-LIST] Taxiing before first flight. (long editorial) |
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