[NSRCA-discussion] YS Questions+more - Rolls

Thu Mar 6 14:30:58 AKST 2008

Tom,  common sense tells us trim would be slightly different for the 
horrizontal roll vs the vertical roll. We live with this, though, without it 
being a problem. If there is any loss of lift when the horizontal roll is 
initiated it does complicate execution of the roll.

My Voodoo does not require right thrust because of all those flow 
straighteners up front, also a nearly balanced rudder about the roll axis. 
Nat

----- Original Message ----- 
From: "Koenig, Tom" <Tom.Koenig at actewagl.com.au>
To: "NSRCA Mailing List" <nsrca-discussion at lists.f3a.us>
Sent: Thursday, March 06, 2008 4:45 PM
Subject: Re: [NSRCA-discussion] YS Questions+more - Rolls

> My head is spinning!!! The more I think about this, the more questions I
> have.........rather than answers!
>
> Maybe the contra rotating prop set up on a Voodoo X( Nat??) maybe the
> answer??
>
> I still 'feel', that the best rolls I get are with a 0 differential set
> up-BUT- somehow I 'drive' that wing to 0 ( or should that be some sort
> of equilibrium??) during the rolls. Certainly in my case, it seems to be
> Pilot dependant!!!
> I'm starting to think that my rudder control has turned to the
> proverbial trying to micro analyse what's happening!
>
> Tom
>
> -----Original Message-----
> From: nsrca-discussion-bounces at lists.nsrca.org
> [mailto:nsrca-discussion-bounces at lists.nsrca.org] On Behalf Of
> shinden1 at cox.net
> Sent: Friday, 7 March 2008 9:15 AM
> To: NSRCA Mailing List
> Subject: Re: [NSRCA-discussion] YS Questions+more - Rolls
>
> what happens on a 4piont?
> Bryan
> ---- Del Rykert <drykert2 at rochester.rr.com> wrote:
>> The general consensus has been that the faster moving molecules over
> the top surface don't require as big as a deflection as the aileron that
> deflects towards the bottom of the plane. What one tries to achieve is
> the plane tracks as purely straight on a string as possible while one
> rolls both directions without introducing any yaw.
>>
>>     Del
>>
>> ----- Original Message -----
>> From: <glmiller3 at suddenlink.net>
>> To: "NSRCA Mailing List" <nsrca-discussion at lists.nsrca.org>
>> Sent: Thursday, March 06, 2008 2:49 PM
>> Subject: Re: [NSRCA-discussion] YS Questions+more - Rolls
>>
>>
>> > Nat and all you other aerodynamicists,
>> >
>> > I thought that the rational for "aileron differential" was that
> upward deflection causes more drag than downward deflection so to
> equalize drag and prevent yaw with aileron deflection, aileron
> differential is needed.  It seems that you guys are now saying that
> ain't so.  Please elaborate.
>> >
>> > George
>> >
>> > ---- Nat Penton <natpenton at centurytel.net> wrote:
>> >
>> > =============
>> > IMO center hinged or top hinged is OK. With top hinge, to achieve
> equal vertical travel of the trailing edge requires different angular
> travel, up vs down. The objective is zero aerodynamic differential.
>> >
>> > Ron I don't think a fairing would prevent separation but, how are
> you able to fair the gap using the top hinge ?            Nat
>> >  ----- Original Message -----
>> >  From: ronlock at comcast.net
>> >  To: NSRCA Mailing List
>> >  Sent: Thursday, March 06, 2008 7:20 AM
>> >  Subject: Re: [NSRCA-discussion] YS Questions+more - Rolls
>> >
>> >
>> >  And while your at it, I'd appreciate some discussion of the impact
> of the top hinge system as seen on Viavat, and Prestige birds -     (top
> hinged, with fairing that eliminates the gap at deflection)
>> >
>> >  Thanks, Ron Lockhart
>> >
>> >    -------------- Original message -------------- 
>> >    From: vicenterc at comcast.net
>> >
>> >    Nat,
>> >
>> >    Could you explain why the differential should be different for
> non-center hinged?  I understand that the mechanical configuration of
> non-center hinged requires differential to obtain same travel in both
> directions.  However, the travel up and down should be close to equal.
>> >
>> >    Thanks,
>> >
>> >    --
>> >    Vicente "Vince" Bortone
>> >
>> >      -------------- Original message -------------- 
>> >      From: "Nat Penton" <natpenton at centurytel.net>
>> >
>> >      Tom
>> >      It's just something that is peculiar to the Southern
> Hemisphere.
>> >
>> >      Changing wing incidence will not help. Unless things are really
> screwed up <G>, at our roll rates, centrifugal forces are too low to
> cause a problem. You want zero differential, aero speaking ( same
> up/down if center hinged ).
>> >
>> >      I find the best check is the fast half-roll in the vertical up.
> Regards     Nat
>> >        ----- Original Message ----- 
>> >        From: Koenig, Tom
>> >        To: NSRCA Mailing List
>> >        Sent: Wednesday, March 05, 2008 7:24 PM
>> >        Subject: Re: [NSRCA-discussion] YS Questions+more
>> >
>> >
>> >        Hi Troy!
>> >
>> >        Thanks for the info. I thought you would be toiling away on
> the next developmental stage of these engines!!
>> >
>> >        Hopefully soon, I can find the time to get flying again. I am
> looking forward to running this little beast. I am still a little
> concerned in keeping it quiet though.
>> >
>> >        Four blade props? I have some of the 18.1 x 12 two bladers
> but I just cant see how I'll shut the thing up with these paint
> stirrers??
>> >
>> >        Also-one more question to any of you out there in pattern
> land.
>> >
>> >        I have struggled with aileron differential for years. I am
> just not happy with the rolls. I have tried various design fixes-but
> about the only one that seems to work is to get the wing back to 0-0 (
> which can be achieved by a few ways, design, mix or thumbs) Differential
> itself does not seem to work if the wing is POA ( well...it works for
> half the roll !)
>> >        Another black magic fix appears to be to run parallel
> ailerons-but this only 'sorta' seems to fix it. I like the feel of
> equal% chord ailerons however.
>> >
>> >        I am frustrated with it-I like my planes to roll as if they
> had a string up its ...........well you know!
>> >
>> >        OK-any 'secrets' I need to know??? Very good elevator work
>> > fixes it ( hence my 0-0 comment)
>> >
>> >        Tom
>> >
>> >
>> > --------------------------------------------------------------------
>> > ----
>> >
>> >
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>
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