<html><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; ">Hi Chris,<div><br class="webkit-block-placeholder"></div><div>Send the pictures. I'm not promising to do it but if it's easy I probably will. </div><div><br class="webkit-block-placeholder"></div><div>Jim O</div><div><br class="webkit-block-placeholder"></div><div><br><div><div>On Mar 13, 2008, at 2:29 PM, krishlan fitzsimmons wrote:</div><br class="Apple-interchange-newline"><blockquote type="cite"><div>Jim, </div> <div> </div> <div>Putting wing adjusters in the Abbra was super easy.. I can send you pics of what I did if you'd like.. </div> <div> </div> <div>Chris<br><br><b><i>James Oddino <<a href="mailto:joddino@socal.rr.com">joddino@socal.rr.com</a>></i></b> wrote:</div> <blockquote class="replbq" style="PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: #1010ff 2px solid">Bryan,<br><br>Thanks for your effort. I agree with you almost completely on fix <br>#1. I'm not sure you can fix the down line. My Impact was pulling to <br>the canopy in both up line and down line. I kept adjusting the wing <br>positive until I fixed the up line. I had some remaining pull in the <br>down line and put in a small amount of down trim with low throttle to <br>take care of that. I'm not sure if I had gone further it would have <br>fixed the down line without screwing up the up line. I analyzed this <br>as increasing the down thrust. I didn't want to change the motor <br>angle so I changed the wing. Make sense. The wing was going to fly <br>at the same incidence with respect to horizontal but the motor would <br>be more negative in level flight, Right? The Impact didn't need any <br>serious mix for knife edge and I'm not sure one could prove anything <br>with it because the wings were like a propeller. Anyway that plane is <br>now a test bed.<br><br>My Abbra seems to fly great with the factory settings in up lines and <br>again I use a small amount of down trim with low throttle to fix the <br>downlines. I have the cg ahead of the factory recommendation but not <br>near as forward as Jerry Budd. I'm guessing that he has more positive <br>in his wing from the factory. I do fly with a little down trim at <br>neutral. The bad news is it takes lots of up mix to fix the knife <br>edges. I guess your solution would be to move the cg forward which in <br>turn would require more positive incidence? I hesitate to modify the <br>airplane to make the wing adjustable until I'm pretty sure I can <br>improve it.<br><br>Thanks again for making us think about this stuff, Jim<br><br><br><br><br><br>On Mar 11, 2008, at 8:05 PM, <shinden1@cox.net><shinden1@cox.net><br>wrote:<br><br>> triangulation trimming,<br>> this is going to be long winded,<br>> I want to preface this discussion by saying I have learned a great <br>> deal from Dean Pappas one of my hero`s in the sport,,Jim Oddino I <br>> read these guys all the time ,,Nat Penton ,,I learned a great deal <br>> about painting from Mike Harrison who is always willing to tell you <br>> what he knows <g>and<br>> I have looked up to Earl Haury as an all around Teacher and <br>> appreciate those guys for their hard work in the sport ahead of <br>> me and willingness to share what they know.<br>> Now let me say I am no flight engineer or aerodynamic Guru , I`ll <br>> leave that title to Nat Penton as he deserves it, But the two guys <br>> that started this flying madness were,, by cycle mechanics,as we <br>> all know .<br>> so I`m in good company<br>> After trimming over 15 of my own designs and trimming and building <br>> two or three airplanes a year for about 20 years I have a lot of <br>> practical knowledge on this subject matter and have kept notes. to <br>> verify my observations I hope this will help.<br>> A better Flyer with more experience will be a better trimmer because <br>> he demands more from his airplane ,,but being a better trimmer will <br>> earn you better flying skills .<br>> so here we go<br>> Mike ,Keith, Jim and Don, thank you for your patience<br>><br>> For the purpose of this discussion tail heavy nose heavy is relative <br>> to the recommended C/G and not always an extreme position just a way <br>> to example it.<br>><br>> If you are using a 0-0 setup things may- be alittle different as to <br>> what I say and what you see on your airplanes as you fly them<br>> my set up and your set up are not to be equated with each other.<br>> and I think that's where some of the confusion comes in you having <br>> only experienced your set ups.<br>> However ,,left rudder tuck is a symptom of the airplane being tail <br>> heavy on all pattern models no matter the set up, as long as the <br>> stab and elevators are accurately adjusted , Extreme tail heavy will <br>> mean both knifes will tuck to the belly. it is just a symptom that <br>> tells me the cure and allows me to diagnose trim problems <see><br my="">> reply to Chad><br>> Jim O,<br>> Any wing has to produce lift, to fly and there are two ways to do <br>> it, add pos inc to the wing according to the datum line on the fuse <br>> My Method or,, add pos inc to the fuse, the 0-0 method ,,,by this <br>> I mean , flying the airplane a little tail heavy to achieve pos <br>> inc ,, there is no way around it ,the wing has to have a pos angle <br>> of attack to produce lift and fly level and lift 11 pounds of balsa <br>> and Glass.<br>> vertical c/g has no factor on this discussion I don`t understand <br>> enough about it to discuss it,{G}<br>> The stab does not induce the lift ,,it controls the lift of the wing <br>> and steers the wing and fuse. {no arguments here please I`m trying <br>> to make the bigger picture I know it does contribute lift and share <br>> the lift load,}<br>><br>> A ,0-0 or sub 1/2pos set up will cause some or all of these <br>> problems ,,for you guys set up 0-0 ,, check um off ,,,<br>> A tuck to the belly on left rudder {or both depending on how tail <br>> heavy} more tail heavy more tuck ,,pull in both up and down <br>> lines ,,,So now we add down thrust to fix one problem upline pull <br>> { as as Jim and others observed and suggested } and it magnifies <br>> the others. like Nat explained to Chad ,,,and now it may give a <br>> differential problem . so we address that with the radio.by mixing<br>> and this occurs,,<br>> stalls may be hard to do because,, "mix dont go away ", Snaps and <br>> spins are hard to perform correctly start,,stop consistently ,and <br>> they wander off line in the uplines,and 4/5`s so you see flyers <br>> using opposite rudder to lead before, and after to keep them on <br>> line , and even more apparently worse in a upline ,,, you can`t <br>> convince these guys that it`s possible to do a snap without <br>> displacing or tucking ect, because they have never experienced it. <br>> and it supports their lack of trimming skills<br>> or a poor design ,Sorry Guys!!<br>><br>><br>> ,,BTW contrary to popular belief nose heavy airplanes {weight <br>> forward } snap better, lands the snap cleaner, and is perfectly <br>> consistently ,stays on line way better , { do you have an <br>> airplane you have to lead to stop ,,its because it does not recover <br>> from the stalled condition its probably tail heavy } a nose heavy <br>> { weight forward} set up stops instantly . providing you have the <br>> right inputs.<br>><br>> In windy weather the 0-0 or sub 1/2 Pos. airplane moves all over <br>> the place and is not solid at all. its not directionally stable , <br>> because of the tail weight needed to induce the pos inc in the wing.<br>> a positive set up will actually weather vein into the wind by itself <br>> and you will need opposite rudder to maintain the line <br>> sometimes ,,in other words it will self correct in the wind ,,this <br>> makes it much easier to fly in windy weather.<br>> now ,,,<br>> every year designers go back to the drawing boards and play with <br>> airfoils, tail moments ,,tail size ,,,hocus pocus ,,ect all in an <br>> attempt to fix a trim problem.,, not a design problem.<br>><br>> Now to this,,, to correctly trim a model you need three tools,<br>><br>> #1 an incidence meter no matter what kind dig. may be better,,<br>> #2 honesty without it you will deceive yourself into believing it`s <br>> trimmed<br>> #3 patience ,,,,I know I just lost some of you But ,<br>> there is only one of these three you can do without ,,, it`s the <br>> inc. meter,, the other two will guide you if you stay at it till <br>> it`s right.<br>><br>> Now the Hebert triangulation Method<br>> assuming everything else is perfectly straight and aligned <br>> correctly ,,, this is a big assumption , but,set your c/g according <br>> to the design spec on the drawings for your design as a starting <br>> point ,,,if you don`t have a C/G spec contact Nat Penton, he will <br>> give you a great formula he has worked up.<br>> # 1 set motor at 1/2 deg down ..neg inc.<br>> wings at 1/2 pos to start ,,,this is not a hard deck<br>> stabs at 1/4 pos because this is about where you will end up.<br>> Line up all your control surfaces get them even, because we are <br>> going to let the airplane tell us what to do to fix it later<br>><br>> #2 fly the airplane trim hands off level flight,, don`t cheat ,,{I <br>> know a lot of guys use a little down trim in upright flight to help <br>> with upline pulls} it has to be hands off perfect then fly <br>> inverted to see if you like the inverted elevator and the airplane <br>> feels solid and easy to hold on a line . and then take notes.<br>> #3 pull a vertical line see what it does<br>> #4 put it straight down see how long it takes to pull out to the <br>> canopy<br>> #5 do a left rudder knife edge ,see if it`s straight no pull the <br>> entire length of the field don`t cheat,,<br>> #6do a right rudder knife edge see if it`s straight same as above.<br>> This is the triangulation method I use to diagnose all trim problems <br>> with any airplane I-MAC to pattern ,,wings are wings.<br>><br>> #7 now land and see where the elevator wound up ,,,never mind the <br>> stabs right now, we will adjust them later.<br>> take notes of what the airplane did in all these three maneuvers, <br>> you will see you can triangulate a common input fix, I find it help <br>> full to have a buddy to help remember whats happening in the air.<br>> Look at the elevator trim and see what it has in it, if we are <br>> lucky and your airplane is 10 pounds you are "all over it" and it <br>> just may take a little c/g to give a click or two one way or the <br>> other.<br>> #1 But, if it pulls in the up lines and downline you need more <br>> pos inc one turn at a time on the adjuster ,,<br>> As an aside ,,,,if you have rear adjusters take them out and put <br>> pins and donuts make sure they do not move at all as this will mess <br>> with the trim process ,,I find the rear adjusters being a different <br>> distance for the wing tube take different amounts of turns to be <br>> equal and the wings have to adjust perfectly and lock exactly. no <br>> warp in the root., yes it happens and gives you a false reading.<br>><br>> #2 if it goes to the belly in left rudder move the c/g <br>> forward{ your tail heavy} untill it stops pulling to the belly <br>> regardless of the inc.<br>> if it goes to the canopy in both knifes #1 will probably <br>> fix it but<br>> refer to the inverted flight part of you notes and see if you<br>> think the elevator was mushy ,hold able but mushy and you might<br>> require tail weight. and pos inc. to fix both problems canopy <br>> pull downlines and knife edge flight.<br>><br>> Because we are on the edge of trim perfection now in all wing <br>> loaded, and unloaded ,positions now we can adjust c/g by using the <br>> earlier mentioned bullet points for fine tune feeling<br>> Remember most of the time one fix will fix 3other things and bring <br>> it all together because they are all related, thats why a well <br>> trimmed airplane rolls with ease and 4 points with ease. because we <br>> are not fighting any adverse trim issues in any axis. or wing load<br>><br>> Now do the adjustments and leave the trims on the airplane like they <br>> are<br>> make another flight your adjustments should Jive with the reverse <br>> of what you trimmed on the first flight and make your trims work ,,, <br>> if you have to increase the trim you already have in there from the <br>> first flight LAND you went the wrong way with the adjustments and <br>> make your corrections again<br>><br>> < on another side note > for my designs since I know where they <br>> should be set ,a quick method is to do the triangulation method this <br>> way ,, trim the airplane to fly the down lines,,, leave this trim <br>> in and land ,,<br>> then adjust the wings to get the trim out and all three Maneuvers <br>> are now happy,,,<br>><br>> The closer you get to the end, the finer the tuning will need to be, <br>> and it can try your patience<br>> make sure the tank is centered on the c/g or you will have trim <br>> changes during the flight as the tank drains<br>><br>> don`t get mad at me if you cannot fix your favorite airplane Just <br>> buy a better design ,,,,Mine preferably <g><br>> there is so much more that I could add But I`ll leave it alone for <br>> another post.<br>> However I would like to add this ,,<br>> I agree with Nat that add on T wings are smoke and mirrors However <br>> who is going to argue with the word Champion ,,<br>> yes it does work ,,somewhat, it reduces the required rudder angle <br>> needed to hold knife edges which will in fact reduce mix ,,less <br>> rudder less mix ,, A POS setup needs none of this.<br>> Hope this helped ,,you may need to read it twice to absorb it all<br>> thanks for your interest ,However Brian Clemons is mad at me because <br>> I was supposed to be painting his airplane tonight LOL<br>> Bryan<br>><br>> Chris F. if you Like you can clean this up and include it for a k- <br>> factor issue<br>><br>><br>><br>><br>><br>><br>><br>><br>> ---- Don Ramsey <donramsey@gmail.com>wrote:<br>>> I'm with Jim in not understand the reason some of the incidence <br>>> changes<br>>> work. Consider increasing the incidence for adjusting the push to <br>>> the belly<br>>> in knife edge. My reasoning would be; increase the incidence, put <br>>> in some<br>>> down elevator to fly straight and level. Roll to knife edge and <br>>> the model<br>>> would then push to the belly more severely. What am I missing?<br>>><br>>> Don<br>>><br>>> -----Original Message-----<br>>> From: <a href="mailto:nsrca-discussion-bounces@lists.nsrca.org">nsrca-discussion-bounces@lists.nsrca.org</a><br>>> [<a href="mailto:nsrca-discussion-bounces@lists.nsrca.org">mailto:nsrca-discussion-bounces@lists.nsrca.org</a>] On Behalf Of <br>>> James Oddino<br>>> Sent: Tuesday, March 11, 2008 10:59 AM<br>>> To: NSRCA Mailing List<br>>> Subject: Re: [NSRCA-discussion] the joy of trimming , left rudder <br>>> tuck<br>>> downline pulls<br>>><br>>> Bryan,<br>>><br>>> I'm trying to figure out how increasing the wing incidence, I assume<br>>> with respect to the fuselage, will get rid of a pull to the canopy on<br>>> a vertical downline. Is it because you need to crank in some down<br>>> trim to make it fly level? Or is it because the tail flies higher in<br>>> level flight and the higher vertical cg creates a couple pushing the<br>>> nose down during the vertical downline?<br>>><br>>> I assume that if one could achieve a good vertical downline with <br>>> power<br>>> off, he could then adjust the thrust to get a good vertical upline?<br>>> It would seem that the thrust is part of what made it fly level and<br>>> you would get into an endless loop chasing things around. What is <br>>> the<br>>> sequence for getting what you want?<br>>><br>>> I adjust the relation between the downthrust and wing to get a good<br>>> vertical upline and trim out the pull in the downline like Chad. <br>>> Tell<br>>> us how we can get a combination of vertical up with power, level with<br>>> power (less power?) and vertical down without power that are all good<br>>> without throttle to elevator trim.<br>>><br>>> Jim O<br>>><br>>><br>>> On Mar 10, 2008, at 5:31 PM, <shinden1@cox.net><shinden1@cox.net><br>>> wrote:<br>>><br>>>> Chad having a small tuck to the belly on left rudder only,,<br>>>> is always a result in a little too much tail weight ,,providing<br>>>> the stab halves and elevator halves are correct.<br>>>> thats whats happening in your wandering 4/5`s<br>>>> the tail weight as is ,,is making you add a little down elevator<br>>>> trim because the wing is flying a little more positive.<br>>>> You want to create the pos angle of attack with the wing only use<br>>>> the tail weight only to adjust the feel for rolls and inverted <br>>>> flight.<br>>>> engine thrust is contributory But ,not doing anything in the left<br>>>> knife edge.<br>>>> it would be happening in the right rudder too.<br>>>> sorry Nat..<br>>>> approach it like this, before you reset the down thrust ,,,because<br>>>> we want to know what really fixed it<br>>>> increase the wing inc 1/32 " more positive or till it stopps<br>>>> pulling in the downline , some airplane require the wing more than<br>>>> 1/2 deg depending on weight and airfoils 1/2 pos. is not a hard<br>>>> deck and you will have to move the cg forward to remove the left<br>>>> rudder knife mix ,,move it till you find a sweet spot , between<br>>>> downlines and both knife edges.<br>>>> , Always remember tail heavy makes the elevator and rudder<br>>>> sensitive and nose wweightmakes them a little numb but much more<br>>>> effective<br>>>> your spins,snaps entry and exits ,, up and downline,45`s will be<br>>>> corrected<br>>>> you will also see improvement in the wind due to the forward c/g and<br>>>> pos inc. add pos wing inc till it stops pulling to the canopy in the<br>>>> downs<br>>>> and let us know what happens<br>>>> Bryan<br>>>> darn now I have given away the family secrets ,And<br>>>> I have just made it harder to beat Chad <g><br>>>><br>>>> ---- Nat Penton <natpenton@centurytel.net>wrote:<br>>>>> Chad<br>>>>> Your problem is caused by the large difference between T/L and<br>>>>> wing. Reduce<br>>>>> the downthrust by 1 deg and reduce the wing incidence by 1 deg ,<br>>>>> and test.<br>>>>><br>>>>> We will go from there.<br>>>>><br>>>>> Your excess downthrust requires up elev trim when under power. You<br>>>>> need to<br>>>>> adjust wing and T/L to avoid other problems. If you just lower the<br>>>>> wing inc<br>>>>> it will go to the belly in knife. If you just reduce the D/T it<br>>>>> will go to<br>>>>> the canopy in<br>>>>> knife. Nat<br>>>>><br>>>>> ----- Original Message -----<br>>>>> From: "Chad Northeast" <chadnortheast@shaw.ca><br>>>>> To: "NSRCA Mailing List" <nsrca-discussion@lists.f3a.us><br>>>>> Sent: Monday, March 10, 2008 4:57 PM<br>>>>> Subject: Re: [NSRCA-discussion] the joy of trim<br>>>>><br>>>>><br>>>>>> Ok you trim masters, here is a tricky one for you.<br>>>>>><br>>>>>> Bryan and I have been through this a bit last year but I ran out<br>>>>>> of time<br>>>>>> before the Worlds to fix it and just flew with what I had.<br>>>>>><br>>>>>> On my Twister I have this pesky problem, the setup is like so,<br>>>>>><br>>>>>> wing = 1/2+ Bryans suggestion and I like it<br>>>>>> stab = 0<br>>>>>> motor = factory claims 2.5 down, have not measured but could if<br>>>>>> asked, I<br>>>>>> have added more to cure a problem see below<br>>>>>> CG = has been anywhere from 275 to 300mm from TE mostly with the<br>>>>>> same<br>>>>>> result. Currently its around 285-290 and it feels good at that<br>>>>>> point. 45<br>>>>>> ups inverted track almost hands off if under enough power.<br>>>>>><br>>>>>> Symptoms,<br>>>>>><br>>>>>> Plane flies well, at this setup I need 0 mix right rudder to ele<br>>>>>> in knife,<br>>>>>> and about 2% up ele with left rudder in knife,<br>>>>>> about 1/32" down elevator with idle to fix a downline<br>>>>>> Added downthrust as the increase in wing inc. and more forward CG<br>>>>>> really<br>>>>>> helped the mix in knife and made rollers easier, but forced an<br>>>>>> increase in<br>>>>>> downthrust as the plane started pulling to the canopy on uplines.<br>>>>>> Downline mix remained the same.<br>>>>>><br>>>>>> The big problem I cannot resolve is this, a 45 deg down upright<br>>>>>> (motor at<br>>>>>> idle) the plane pitches to the belly and will not track on its own<br>>>>>> for any<br>>>>>> length of time. If I switch the idle-down mix off its rock solid<br>>>>>> on that<br>>>>>> line.<br>>>>>><br>>>>>> I am open to all suggestions now that I have a bit of time to play<br>>>>>> with<br>>>>>> this, I hope Bryan chimes in some more as I would like to continue<br>>>>>> where<br>>>>>> we left off last fall. If you suggest something I will do my best<br>>>>>> to give<br>>>>>> it a go and let you know how it works (provided it doesn't snow!)<br>>>>>><br>>>>>> The plane is basically super locked in with this setup, except for<br>>>>>> the<br>>>>>> silly 45 down upright, which is a problem in cubans and such.<br>>>>>><br>>>>>> Comments and thoughts from the masters are most appreciated :) I<br>>>>>> consider<br>>>>>> myself one of the, cant really trim that well but can fly through<br>>>>>> it just<br>>>>>> fine types :)<br>>>>>><br>>>>>> Chad<br>>>>>><br>>>>>> _______________________________________________<br>>>>>> NSRCA-discussion mailing list<br>>>>>> <a href="mailto:NSRCA-discussion@lists.nsrca.org">NSRCA-discussion@lists.nsrca.org</a><br>>>>>> <a href="http://lists.nsrca.org/mailman/listinfo/nsrca-discussion">http://lists.nsrca.org/mailman/listinfo/nsrca-discussion</a><br>>>>>><br>>>>><br>>>>> _______________________________________________<br>>>>> NSRCA-discussion mailing list<br>>>>> <a href="mailto:NSRCA-discussion@lists.nsrca.org">NSRCA-discussion@lists.nsrca.org</a><br>>>>> <a href="http://lists.nsrca.org/mailman/listinfo/nsrca-discussion">http://lists.nsrca.org/mailman/listinfo/nsrca-discussion</a><br>>>> _______________________________________________<br>>>> NSRCA-discussion mailing list<br>>>> <a href="mailto:NSRCA-discussion@lists.nsrca.org">NSRCA-discussion@lists.nsrca.org</a><br>>>> <a href="http://lists.nsrca.org/mailman/listinfo/nsrca-discussion">http://lists.nsrca.org/mailman/listinfo/nsrca-discussion</a><br>>><br>>> _______________________________________________<br>>> NSRCA-discussion mailing list<br>>> <a href="mailto:NSRCA-discussion@lists.nsrca.org">NSRCA-discussion@lists.nsrca.org</a><br>>> <a href="http://lists.nsrca.org/mailman/listinfo/nsrca-discussion">http://lists.nsrca.org/mailman/listinfo/nsrca-discussion</a><br><br>=== message truncated ===</nsrca-discussion@lists.f3a.us></chadnortheast@shaw.ca></natpenton@centurytel.net></g></shinden1@cox.net></shinden1@cox.net></donramsey@gmail.com></g></see></g></shinden1@cox.net></shinden1@cox.net></blockquote><br><br><br><div><strong><em><font face="comic sans ms" color="#0000bf" size="3">Chris </font></em></strong></div> <div> </div> <div> </div> <div> </div><p> __________________________________________________<br>Do You Yahoo!?<br>Tired of spam? Yahoo! Mail has the best spam protection around <br><a href="http://mail.yahoo.com">http://mail.yahoo.com</a> _______________________________________________<br>NSRCA-discussion mailing list<br><a href="mailto:NSRCA-discussion@lists.nsrca.org">NSRCA-discussion@lists.nsrca.org</a><br>http://lists.nsrca.org/mailman/listinfo/nsrca-discussion</p></blockquote></div><br></div></body></html>