[NSRCA-discussion] the joy of trimming , left rudder tuck downline pulls

[Matthew Frederick]

I must be getting the hang of this... first thing I thought was add a little 
incidence in the wing. Even though the down thrust is a bit much... Like 
Bryan says all the time: wing incidence trumps it all. CG, thrust, and stab 
incidence are used for extreme fine tuning. You gotta get that incidence 
right first...

Matt
----- Original Message ----- 
From: <shinden1 at cox.net>
To: "NSRCA Mailing List" <nsrca-discussion at lists.nsrca.org>
Sent: Monday, March 10, 2008 7:31 PM
Subject: [NSRCA-discussion] the joy of trimming ,left rudder tuck downline 
pulls


> Chad having a small tuck to the belly on left rudder only,,
>  is always a result in a little too much tail weight  ,,providing the stab 
> halves and elevator halves are correct.
> thats whats happening in your wandering 4/5`s
> the tail weight as is ,,is making you add a little down elevator trim 
> because  the wing is flying a little more positive.
> You want to create the pos angle of attack with the wing only use the tail 
> weight only to adjust the feel for rolls and inverted flight.
> engine thrust is contributory But ,not doing anything in the left knife 
> edge.
> it would be happening in the right rudder too.
> sorry Nat..
> approach  it like this, before you reset the down thrust ,,,because we 
> want to know what really fixed it
> increase the wing inc 1/32 "  more positive  or till it stopps pulling in 
> the downline , some airplane require the wing  more than 1/2 deg 
> depending on weight and airfoils 1/2 pos. is not a hard deck and you will 
> have to move the cg forward to remove the left rudder knife mix ,,move it 
> till you find a sweet spot , between downlines and both knife edges.
> , Always remember tail heavy makes the elevator and rudder  sensitive  and 
> nose wweightmakes them a little numb but  much more effective
> your spins,snaps entry and exits ,, up and downline,45`s will be corrected
> you will also see improvement in the wind due to the forward c/g and pos 
> inc. add pos wing inc till it stops pulling to the canopy in the downs
> and let us know what happens
> Bryan
> darn now I have given away the family secrets ,And
> I have just made it harder to beat Chad <G>
>
> ---- Nat Penton <natpenton at centurytel.net> wrote:
>> Chad
>> Your  problem is caused by the large difference between T/L and wing. 
>> Reduce
>> the downthrust by 1 deg and reduce the wing incidence by 1 deg , and 
>> test.
>>
>> We will go from there.
>>
>> Your excess downthrust requires up elev trim when under power. You need 
>> to
>> adjust wing and T/L to avoid other problems. If you just lower the wing 
>> inc
>> it will go to the belly in knife. If you just reduce the D/T it will go 
>> to
>> the canopy in knife.                                                  Nat
>>
>> ----- Original Message ----- 
>> From: "Chad Northeast" <chadnortheast at shaw.ca>
>> To: "NSRCA Mailing List" <nsrca-discussion at lists.f3a.us>
>> Sent: Monday, March 10, 2008 4:57 PM
>> Subject: Re: [NSRCA-discussion] the joy of trim
>>
>>
>> > Ok you trim masters, here is a tricky one for you.
>> >
>> > Bryan and I have been through this a bit last year but I ran out of 
>> > time
>> > before the Worlds to fix it and just flew with what I had.
>> >
>> > On my Twister I have this pesky problem, the setup is like so,
>> >
>> > wing = 1/2+ Bryans suggestion and I like it
>> > stab = 0
>> > motor = factory claims 2.5 down, have not measured but could if asked, 
>> > I
>> > have added more to cure a problem see below
>> > CG = has been anywhere from 275 to 300mm from TE mostly with the same
>> > result.  Currently its around 285-290 and it feels good at that point. 
>> > 45
>> > ups inverted track almost hands off if under enough power.
>> >
>> > Symptoms,
>> >
>> > Plane flies well, at this setup I need 0 mix right rudder to ele in 
>> > knife,
>> > and about 2% up ele with left rudder in knife,
>> > about 1/32" down elevator with idle to fix a downline
>> > Added downthrust as the increase in wing inc. and more forward CG 
>> > really
>> > helped the mix in knife and made rollers easier, but forced an increase 
>> > in
>> > downthrust as the plane started pulling to the canopy on uplines.
>> > Downline mix remained the same.
>> >
>> > The big problem I cannot resolve is this, a 45 deg down upright (motor 
>> > at
>> > idle) the plane pitches to the belly and will not track on its own for 
>> > any
>> > length of time.  If I switch the idle-down mix off its rock solid on 
>> > that
>> > line.
>> >
>> > I am open to all suggestions now that I have a bit of time to play with
>> > this, I hope Bryan chimes in some more as I would like to continue 
>> > where
>> > we left off last fall.  If you suggest something I will do my best to 
>> > give
>> > it a go and let you know how it works (provided it doesn't snow!)
>> >
>> > The plane is basically super locked in with this setup, except for the
>> > silly 45 down upright, which is a problem in cubans and such.
>> >
>> > Comments and thoughts from the masters are most appreciated :)  I 
>> > consider
>> > myself one of the, cant really trim that well but can fly through it 
>> > just
>> > fine types :)
>> >
>> > Chad
>> >
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>> >
>>
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