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General control line discussion => Open Forum => Topic started by: M Spencer on November 15, 2023, 08:22:25 PM
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Thought Id update the error !
Diheadral / YAW -
Was o.k. with old 20 ounce OS 80 with 72 Wt . Pig to start . untrained & tight .
So some twit butched it for a S Tigre 60 , and a 6 ounce cowl under . HOWEVER
with the bearers now up top :( the vertical c.g. is higher and WEIGHT is 76 ounce .
OUCH .
First Flights with OS 80 wernt bad . fairly stable . Rabes anaylis = Light controls but stability - or somesuch , from his bearcat - seem to apply . But More .
AS it did the shedule reasonably on its 3rd flight - theres hope yet . :(
IF I build a 16 th sheet millenium ish wing . Theres a sheet on a fuse plug ( still ) now . AND a Rabeish rear ( Light 16th empenage ) and a 2 pot finish .
Use controls & flaps & a plug from the cowl. ( Its all pretty much SCALE )
With the ST 60 its a bit toey . as enough is enough . LEAD . but a 4 foot corner aint bad . S?P However a severe yaw / roll , on a 18 inch corner occurs .
(https://stunthanger.com/smf/index.php?action=dlattach;topic=48420.0;attach=277493;image)
(https://stunthanger.com/smf/index.php?action=dlattach;topic=48420.0;attach=277501;image)
outta time .
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Right , where all this #@&! is leading is DIHEADRAL .
As there was a thread on such , the cogitive faculty has been engaged. There .
Effect ONE / . Non longitudeinal ( to flight ) airflow .
Visualise if it flew sideways and had no fuselage %^@ ( say it stopped upwind ( or downwind )) .theoretically . And was ' level ' ( which brings in MORE irrtating factors )
ALL ONE WING would have the airflow on the underside . All the other wing ( if we ignore the other wing VD~ ) would have ALL the flow ( spanwise ) topside . Blowing it DOWN .
of couse the underside blown one would blow up . Likewise the pilot also LL~ .
NOW if we consider it 45 Degree Yawed , its no disimilar . So at say 5 or 10 or 20 Deg. YAW to working airflow the diheadral iduces rolling .
SUDDEN Yaw gets Sudden Snap in Roll Plane . :( as we have observed :( :( ) So therefore if anyones considering semi scale diheadraled designs , a first priority is yaw ellimination .
Just to further encourage such endevours - It would appear that inside turns have a L E SWEEP percentage effect opposite to outsides . As illustrated by my shadow . FOR THOSE CONTEMPLATEING DIHEADRAL
for F2B.
(http://stunthanger.com/smf/index.php?action=dlattach;topic=45348.0;attach=263413;image)
Any of the several gan get awkward , when its a lousy motor run . ( like any other plane does )
WHEN , it's ' locked in ' to a solid ' working ' motor run theyre usually very sharp .
The Stab. Elevator is less in a plane of wake from the wing / flaps . as theyre not in the same plane. always . So theres a softer transition in through and out of the wing wake , which working hard there is .
The M B 3 with Rabe ' Mustang 5 ' airfoil , perhaps ' flew itself ' smoother and accurater . The P -51 of mine , with a Hunt werwage airfoil is crisp & sharp to fly .
I think the greeny / goldy big ' unfinish ' finished ( plain tissue ) was brilliant , in smooth air & wind . A carry on from the M B , the pilot was trained by then . Superb incremental control ( the Plane . ! VD~ )
so DIHEADRAL , for ELECTRIC is likely quite workable if your a one plane man , as it were . and are prepaRED TO BUTCHER SAY LEADOUT GUIDES , RUDDER . outthrust etc etc , to refine & tune .
They do this on centerboard sailboats . Or did, on timber ones . on occasion . RACE . To get it ' trimmed ' for best efficency . Waves & air are / can be ' choppy ' so similarities on dynamics & forces
are comparable in substance .
All mine have had bellcrank flat in wingtop , leadouts under inner tip . IF theb leadouts DIDNT need to be FLAT . ( in theory & fact ! # ? ) , say you got one of mine , threw the leadout guide UP to the
vertical center of gravity , it might make things a LOT SIMPLER . BUT i ENVISAGE - IMAGINE - LOOK AT IT, as if the thing were BLOWN SIDEWAYS rather firmly , itd align the leadouts flat with the lines .
That may be a flawed peception . But Leaning back boots kicked into the turf and using both hands on the handle - one is apt to look at it like that .
A KID FLYING A fp 40 cOMBAT WING WAS INSTRUCTED TO fly lower . " I CANT " Below 40 degrees his bare feet were sliding in the mud .
Hence previous illustrations of wind Surfers and sail wing surfers . If its blowing its pulling. and theres a lot of centers of things . side drag . momentum weight inertia the handle balaNCE MASS AND WORKING FORCES
just to annoy you , personally .
Less Complicated airframe shapes are perhaps less prone to variations throuh airflow under such varying ( Dynamic -> MOVING - unconstant ) " effects " . moments and vectors . ~^ so its all quite simple really.
If you ignore them all . H^^
( afterthought : that seems to be born out - The MB3 & greeny goldy Mewgull were the more simple plainer configurations - without notable protrudences and excresences to DISRUPT THE AIRFLOW . Old Boy . %^@ )
( Therefore the leadout guide dead on the vertical C G may be the first consideration for a full time competitive Comp. ' scale stunt ' or interpretation . Putting it thyere then moving it off , would tell you , perhaps . )
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Larry, Buttafucco Stunt Team
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Larry, Buttafucco Stunt Team
Larry: my thoughts EXACTLY!