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<DIV>I agree. I did the same in my Abbra. I also have pictures.</DIV>
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<DIV class=signature id=signature>--<BR>Vicente "Vince" Bortone</DIV>
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<BLOCKQUOTE style="PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: #1010ff 2px solid">-------------- Original message -------------- <BR>From: krishlan fitzsimmons <homeremodeling2003@yahoo.com> <BR>
<DIV>Jim, </DIV>
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<DIV>Putting wing adjusters in the Abbra was super easy.. I can send you pics of what I did if you'd like.. </DIV>
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<DIV>Chris<BR><BR><B><I>James Oddino <joddino@socal.rr.com></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 m
atter 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 my <br>> 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 win
g 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 o
pposite 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 stab
le , <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 ot
her 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 adjustm
ents 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: nsrca-discussion-bounces@lists.nsrca.org<BR>>> [mailto:nsrca-discussion-bounces@lists.nsrca.org] 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 increa
sing 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>>>> yo
ur 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>&g
t;>>>><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>>>>&g
t;><BR>>>>>> _______________________________________________<BR>>>>>> NSRCA-discussion mailing list<BR>>>>>> NSRCA-discussion@lists.nsrca.org<BR>>>>>> http://lists.nsrca.org/mailman/listinfo/nsrca-discussion<BR>>>>>><BR>>>>><BR>>>>> _______________________________________________<BR>>>>> NSRCA-discussion mailing list<BR>>>>> NSRCA-discussion@lists.nsrca.org<BR>>>>> http://lists.nsrca.org/mailman/listinfo/nsrca-discussion<BR>>>> _______________________________________________<BR>>>> NSRCA-discussion mailing list<BR>>>> NSRCA-discussion@lists.nsrca.org<BR>>>> http://lists.nsrca.org/mailman/listinfo/nsrca-discussion<BR>>><BR>>> _______________________________________________<BR>>> NSRCA-discussion mailing list<BR>>> NSRCA-discussion@lists.nsrca.org<BR>>> http://lists.nsrca.org/mailman
/listinfo/nsrca-discussion<BR><BR>=== message truncated ===</BLOCKQUOTE><BR><BR><BR>
<DIV><STRONG><EM><FONT face="comic sans ms" color=#0000bf size=3>Chris </FONT></EM></STRONG></DIV>
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