Throt/ Rud
Bill Glaze
billglaze at triad.rr.com
Thu Jan 27 22:15:02 AKST 2005
Dave:
We are in agreement about your statement below. Change anything at all,
and you are now out of trim for the new flight condition. Bill Glaze
David Lockhart wrote:
> I too spoke with Dick Hanson at length about right thrust about the
> time he brought out the EMC design. My recollection was that his
> contention was that the amount of right thrust that was "correct" was
> only correct for a given power setting and given airpspeed (and I
> agree). So just learn to fly the rudder. I found on the EMC that 2.5
> degrees of right thrust had very little if any adverse effects, and
> reduced the amount of rudder needed in a number of places.
>
> Regards,
>
> Dave
>
> ----- Original Message -----
> From: Ed Miller <mailto:edbon85 at charter.net>
> To: discussion at nsrca.org <mailto:discussion at nsrca.org>
> Sent: Thursday, January 27, 2005 5:01 PM
> Subject: Re: Throt/ Rud
>
> I copied Dave Lockhart's EMC2 setup on mine which included 2 1/2
> degrees right thrust which seemed perfect with the APC 15.75 x 11
> 3 blade prop. I can tell you on pulls to verticals the plane will
> track straight for nearly 2 box heights with no rudder input. I
> did not notice a problem with yawing when slowing the plane
> upright or inverted, guess it all depends on the design.
> Ed M.
>
> ----- Original Message -----
> From: Dean Pappas <mailto:d.pappas at kodeos.com>
> To: discussion at nsrca.org <mailto:discussion at nsrca.org>
> Sent: Thursday, January 27, 2005 3:08 PM
> Subject: RE: Throt/ Rud
>
> All I have is guesses, I will go out and try this with the
> plane I'm fiddling with, now.
> Dean
>
>
> Dean Pappas
> Sr. Design Engineer
> Kodeos Communications
> 111 Corporate Blvd.
> South Plainfield, N.J. 07080
> (908) 222-7817 phone
> (908) 222-2392 fax
> d.pappas at kodeos.com <mailto:d.pappas at kodeos.com>
>
> -----Original Message-----
> From: discussion-request at nsrca.org
> <mailto:discussion-request at nsrca.org>
> [mailto:discussion-request at nsrca.org]On Behalf Of Bill Glaze
> Sent: Thursday, January 27, 2005 1:48 PM
> To: discussion at nsrca.org
> Subject: Re: Throt/ Rud
>
> I hesitate to get something started here, but here goes
> anyway<G>:
> A long conversation I had with Dick Hanson ~1996 or so,
> was about right thrust. Dick said that "it wasn't needed"
> on our pattern planes; in fact, he had a 0-0-0 airplane
> with his EMC. His feeling was that you needed to be on
> the rudder all the time anyway, so zero things out so that
> you knew where you stood all the time. He felt that your
> fingers could do all the tricks needed. Countering Dick's
> statement, I will say that every full-size propellor
> driven airplane I ever flew had some right thrust. (Well,
> except for the DC-6) so the full-size designers didn't
> share Dick's philosophy. That's O.K. though, because of
> different functions/sizes of airframe. However, the right
> thrust did lead to some funny things. The P-51 Mustang
> had a little right thrust, (can't remember how much) and
> an offset fin that put in some right rudder. Reading the
> -1 manual stated that "when all power is removed for
> landing, some input of LEFT rudder may be required."
> Interestingly, I have been able to observe some of the top
> fliers at the Nats. Their airplanes were visibly flying
> perfectly smoothly straight and level. But, if you
> observed their transmitter at the same time, you would
> notice that their fingers were always busy inputting tiny
> amounts of control. They didn't do like some of us (ahem)
> do, which is try to trim the airplane so it's hands off,
> then just let it fly itself.
> Anyway, I'm just interested in the different schools of
> thought about this engine offset versus trimming. I
> expect to learn something from this thread.
> Bill Glaze
>
> Dean Pappas wrote:
>
>> Agreed with both of you.
>> What's more, in the past, when it looked like a plane
>> required too much right thrust, and would developo the
>> warts that have been described, I would reduce the right
>> thrust until pulls took the same amount of right rudder
>> as pushes required left. My guess is that that is the
>> ideal right thrust setting from which to start fiddling
>> with the radio.
>> Regards All,
>> Dean
>>
>>
>> Dean Pappas
>> Sr. Design Engineer
>> Kodeos Communications
>> 111 Corporate Blvd.
>> South Plainfield, N.J. 07080
>> (908) 222-7817 phone
>> (908) 222-2392 fax
>> d.pappas at kodeos.com
>>
>> -----Original Message-----
>> From: discussion-request at nsrca.org
>> [mailto:discussion-request at nsrca.org]On Behalf Of Nat
>> Penton
>> Sent: Thursday, January 27, 2005 12:14 PM
>> To: discussion at nsrca.org
>> Subject: Re: Throt/ Rud
>>
>> Bravo Bob Richards !
>>
>> ----- Original Message -----
>> From: Bob Richards <mailto:bob at toprudder.com>
>> To: discussion at nsrca.org
>> <mailto:discussion at nsrca.org>
>> Sent: Thursday, January 27, 2005 7:15 AM
>> Subject: Re: Throt/ Rud
>>
>> Ed,
>>
>> I am a very firm believer (no one will convince
>> me otherwise) of exactly what you describe.
>> Slipstream effect is the whole reason we put
>> right thrust in our engines. It has NOTHING to do
>> with torque, P-factor
>> <http://home.earthlink.net/%7Ex-plane/FAQ-Theory-PFactor.html>,
>> or gyroscopic precession
>> <http://www.cybercom.net/%7Ecopters/aero/gyro.html>.
>>
>> The issue of transitioning from vertical to
>> horizontal (either to inverted or upright) is a
>> gyroscopic precession issue. The best way to
>> counter that is to use lighter weight props
>> turning at lower rpm -- less spinning mass and
>> less gyroscopic effect.
>>
>> P-factor only exists at high angle of attacks,
>> which does not happen in a vertical climb.
>>
>> Torque tries to roll the plane, and some schools
>> of thought are that, to counter the
>> torque-induced roll, the left wing has to lift
>> more than the right, causing more induced drag on
>> the left. While this may be true for a lot of
>> planes while taking off, this does not apply to
>> pattern planes in a vertical climb since both
>> wing panels would be fighting the torque equally.
>>
>> Gyroscopic precession only occurs when the
>> airplane is moving around its pitch axis, as when
>> pulling or pushing a corner. It is most
>> noticeable when the airplane is slow, since there
>> is less aerodynamic stabilizing force available
>> from the rudder/fin. IMHO, no throttle-rudder
>> mix is going to correct this. It might be
>> possible to mix elevator to rudder, and
>> enable/disable the mix based on throttle position.
>>
>> When I flew a Cap21 in pattern, I had to use left
>> rudder when pulling an inside corner at the top
>> of square loops. I had to use a TON of right
>> rudder when pushing a corner, and this was with
>> about 5 degrees of right thrust.
>>
>> IMHO, learn to do it with your thumbs. Practice
>> enough and it will become automatic. Just my 2CW.
>>
>> Bob R.
>>
>>
>> Edward Skorepa <edsko at xmission.com> wrote:
>>
>> I'm confused too. I know, I know I shouldn't
>> argue with someone like chip but I believe
>> the main reason we're putting right thrust is
>> an asymmetric vertical fin. On most
>> conventional airplanes the area above thrust
>> line is much greater then area below. So, the
>> spiraling slip stream will hit the top
>> portion of the vertical fin from the left
>> pushing tail to the right thus right thrust.
>> When inverted, the spiraling slip stream will
>> hit vertical fin from the right because fin
>> is now on the opposite side and pushes tail
>> to the left. To straighten the flight path,
>> we need now the left thrust which is already
>> there. During inverted push ups, why do we
>> need to use left rudder? The spiraling slip
>> stream misses completely vertical fin and the
>> right (left when inverted) thrust is causing
>> airplane to yaw left. If you have a big
>> gasser, turn on smoke, do inverted push up
>> and watch where the smoke goes. However,
>> Chip's approach of fixing ! the inverted push
>> ups problem is quite interesting and I'll try
>> it on my new bird I'm working on right now.
>> ed
>>
>> ------------------------------------------------------------------------
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