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Author Topic: Over Turning - Oversteer  (Read 1893 times)

Offline Matt Spencer

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Over Turning - Oversteer
« on: June 03, 2017, 08:51:41 PM »
Gees , we could have a New Board for TRIMMING !  ;D

The *#% P 51 was tightening the loops considerably in a bit of a blow the last time I had it out .

Wind behind it and you needed to ease the turns open a considerable extent , in the lower half of the circle.
Maybe the opposite above half way up ( 45 Deg . )

WONDERING .

Either Aft C.G. ,

Soft Horns ( theyre the 3 /32 anealed suckers , it should really have 1/8 in. dia. ones .  >:()

Gees , we could have a New Board for TRIMMING !  ;D

The *#% P 51 was tightening the loops considerably in a bit of a blow the last time I had it out .

Wind behind it and you needed to ease the turns open a considerable extent , in the lower half of the circle.
Maybe the opposite above half way up ( 45 Deg . )

WONDERING .

Either Aft C.G. ,

Soft Horns ( theyre the 3 /32 anealed suckers , it should really have 1/8 in. dia. ones .  >:()

The thing weighs 65 Oz odd, not 55 Oz.  ??? >:(

Its not a flexi flyer ( airframes quite ridgid )

Was on 65 ft of .015 solids .

Was bucking and weaving like a CB 750 on a bumpy dirt road .



Pic of Mumbo Jumbo Jet Mechanic / Engineer( ( Bro ) with a dearth of crop on top ) To Illustrate Plane .

Mayve just been to open a handle spacing & pilots brain at half mast . As in flying appalingly - & the wind .

BUT hesitateing into turns ( at times ) and with wind across the right shoulder loops etc closing up 30 %  etc .
C.G. about on the spar or ! /2 in Fwd .as the G -51 was in it . Wasnt a good engine run either .

The Wind Up . / gusting steadyish & rolling arout 15 Kt. is . Ea side that is .

The thing weighs 65 Oz odd, not 55 Oz.  ??? >:(

Its not a flexi flyer ( airframes quite ridgid )

Was on 65 ft of .015 solids .

Was bucking and weaving like a CB 750 on a bumpy dirt road .

Think I had a 10 x 6 3 blade on it for the first flight , and a 12 x 5 T?f on the 2nd . Off Runs , a bit weak . so noot ' locked in ' at all .
more like at the mercy of the currents .  :(

SO was the severe tightening of the turns , when flown roughly & the pilot way off the mark , just that . Or indicitive of C.G.  way out .  :-\



Online Brett Buck

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Re: Over Turning - Oversteer
« Reply #1 on: June 03, 2017, 09:09:44 PM »
Gees , we could have a New Board for TRIMMING !  ;D

The *#% P 51 was tightening the loops considerably in a bit of a blow the last time I had it out .

Wind behind it and you needed to ease the turns open a considerable extent , in the lower half of the circle.
Maybe the opposite above half way up ( 45 Deg . )

   Add noseweight until it tracks in rounds, then see if it "hops" out of corners, if to, decrease the elevator travel with respect to the flap, and reset the CG so it tracks in rounds again. Since you moved the CG forward in the first step, you will probably have to move it back when you decrease the elevator travel.

      Brett

Online Ted Fancher

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Re: Over Turning - Oversteer
« Reply #2 on: June 05, 2017, 07:01:24 PM »
The thing that jumps out at me is the apparent aspect ratio of the wing in the pictures.   which don't show the entire wing.  Curious what the span and total area of the wing are?  Also, what is the tail area?

Wind and high aspect ratios aren't natural best buddies.  If the ship is winding up (going faster and faster) as the loops tighten in the wind there might well be a need for creative trimming.  CG location at the half span would be of great interest as well so as to determine where the CG is as a % of the Mean Aerodynamic Chord.

In the interim I concur with Brett's suggestion to add nose weight as an interim solution.

Ted Fancher

Offline Matt Spencer

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Re: Over Turning - Oversteer
« Reply #3 on: June 05, 2017, 09:29:25 PM »
Thanks ,

Going to dig out the ' sausage ' S Tigre muffler , with ten little holes & the aft bunged . Seems not to restrict things . Seeing as how tounges are often used to
choke FP 40s ! . This'll pull the weight Fwd .( and inbd.  >:() Gotta choice there , and I will pick up some stick on tyre weights .

Theres three videos of it flying ( earlier ) here .

Como 51 is back in it , for now . Cleaned out the motor and it seems at least consistant . Wasnt before .

A pic , more in planform . Span theres 61 in .  Not a tandem wing ! Will gat the Areas , and check as you suggest @ 1/2 span .
Ive got a weird Semi Symetrical Airfoil At Root going to Symetric at the L E Kink . REAR - aft of spar , is Symetric right through .

( The L E Droops , landing gear to Fuse ) Seems to get V Good Sq.'s with it . That and the flow thru Rad. are unknowns , thou - perhaps .

Thinking some of it is horns arnt entirely ridgid ( A Genisis Ive got here similar - wind Load steers it a way . Not Good . Totally Ridgid controls arnt a bad idea .
Other was motor run wasnt brilliant .
Also Pilot was at about 3/10ths as to ' mind on the job .

Will have to re Fuselage it To Get 1/8 Horns in , or at least a major butcher job . Pushrod ETC is ok .

Offline Matt Spencer

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Re: Over Turning - Oversteer
« Reply #4 on: June 05, 2017, 09:31:37 PM »
Go To 2 : 30 to avoid parambulations .been Sweltering for 8 Hrs .



Calmish Here , Horns mayve been ' overloading ' in the gusty air Im whining about . That Said ' NEUTRAL ' was not what it was at , having flow ' a bit '
( Several Gallons ) in the wind in N Z . Kuringai has gusty turbulant air with trees hills & gullies , unpredictable & variable direction , So ' Of Runs ' on
the motor wernt helping . Was just Flat - Not Res[ponsive Engine Run .

http://stunthanger.com/smf/index.php?action=dlattach;topic=43652.0;attach=262818;image


Offline Matt Spencer

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Re: Over Turning - Oversteer
« Reply #5 on: June 06, 2017, 11:12:55 PM »
o.k. Outer Wings 31 ! ( :-X) mid span 10 1/2 in chord . actual - not bothering with rake fwd further in . Think I used scale planform .

Forgot to measure tailplane . Think its 22 in. ( been preoccupied with Typhoon ) will measure & probly find its 23 in .  :-\

INDEED , 23 at hinge X 5 1/2 in chord @ half span .

Airfoils more a traditional ' tear drop ' , not al's High lift one , which Id thought uneeded If I got it down to 55 Oz .

Have to dig out the lightest wood for one soon .  :(
« Last Edit: June 07, 2017, 11:17:38 PM by Matt Spencer »

Offline Matt Spencer

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Re: Over Turning - Oversteer
« Reply #6 on: September 24, 2017, 07:22:22 PM »
RIGHT , We've solved it .

6 mm slack at T.E. of Elevator did it , nicely .

Thought Id better relate the trial , as it may help some other sucker . . .

Put in the 1/8 Elevator Horn , same as before - inverted It'd pick up a pitch / up - down , after a few laps . Or related to how ' with it ' the pilot was . Coll calm & collected it might not do it , perhaps . . .
Ploughing through old A M A - M.A. info , found one relating Al Rabe ran the ' Dead Zone ' Tailplane , and Bob Gieske thought 1/8 to 1/4 freeplay at T E ( NONE at Flap ) essential .
As  Id contemplated it during construction , AFTER having tried 4 Oz ( Stalled in Sqs , ) 1 1/2 , 1 ( good ) , & 1/2 (o.k. ) & zero ( or Minus if you consider No Cowl ) on the sucker ,
with the STALKER 66 in it now . Also on a 13 x 6 with rounded T E Tips , it went VERY Light on Insides , moreso with the noseweight . The Olde 'P' effect evident , we presume .
Seems happy on a 12 x 5 T F wood . Wont slow down on a 6 in pitch . Tho alledgedly the Proto 66 , so not neccesarilly applicable to all of em . ANYWAY the 12/5s good here . Summer .

Carved out the rear last week to bush the rear horn or something . THIS week after a hours hunt ( it was on the floor by the vice ! ) at midnight installed a 3/16 K&S brass tube !
FLATTENED to accept a pair of 3/32 drill bits . . I.E. , the ' bush ' is 3/32 x 3/16 , - giving 3/32 ' freeplay ' at the horn ' 3:1 ratio Horn to ( 3" ) Chord .

Still Cowl Off , the suckers ' got a groove ' , and at maybe 20% chord C.of G. , thereabouts .

Gotta mould for a new cowl half done , am En Route  for more F'Glass cloth . Stalker Cyl is more aftish & R E . So C G may be spot on  :-\ with it fitted . Tho a new smaller tank may stuff that .Slightly .

A few patches & a bit of tarting up required .

Co-Ercced a Ace to handle a Flight .Was a few loops and straight into Sq Eights . Nice straight clean even ones . So seems o.k. Though Advice Was to Close Handle Spacing . ( any irregularities in
the wrist wobble gets it following em in such as the Over Heads .

So Basically It Good Now . Do the Cowl & tart up a few patches . New Smaller ( 135 cc ) Tank . Maybe a half ounce ( 15 g ) of Nose Weight . Tho spinner / prop combo may cover that there .    S?P

PLUS She's got a bloody tight corner in the Squares. :) near 1:1 Ratio on the controls . Same deflection from center ( 1 7/8 ) flaps & elevator . TOTAL , so a tad more as the 6 mm slacks a notch there .

Offline Serge_Krauss

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Re: Over Turning - Oversteer
« Reply #7 on: September 25, 2017, 09:26:46 PM »
If I click on Matt's pictures and drag the cursor, I get a little images that show the entire original pictures (includes more of plane than shown in each full-sized picture).

Offline John Tate

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Re: Over Turning - Oversteer
« Reply #8 on: November 15, 2017, 09:48:02 PM »
The flaps look too big to me. I had a Cardinal, (which has large flaps) and it did the same thing that is happening to you. I cut the length of the flaps down some and the problem went away.

Offline Matt Spencer

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Re: Over Turning - Oversteer
« Reply #9 on: November 19, 2017, 09:46:56 PM »
Got it sorted John , apart from the Pilot . Or Opposition  ;D .

The slack in Elevator now / dead zone , got ' the groove ' .

Playing with a Stalker 76 in it , though The G 51 seems better , to me . Not enough time with the Como 51 to get definitave . Tho 4 in pitch
required on that . Dunno if the ' on - off ' bit is in it , there .

Was the usual ' cummulative ' effect of more than one or two  things . H^^


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