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Author Topic: Wind Trim Adjustments  (Read 1859 times)

Offline Ken Culbertson

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Wind Trim Adjustments
« on: June 07, 2018, 11:16:09 AM »
My final hurdle in getting back into the swing of things is competition which, after 35 years, will happen this weekend.  I would like some advice on re-trimming for wind.  I have never had the luxury of having everything adjustable and I doubt there will be time to do a test flight in the wind.  Our usual weather will be 0-5mph at 6:30 when practice starts to 10mph for the 1st round and about 15 for the 2nd.  This is the first competition I will have attended with adjustable leadouts.  Do you change them for wind?  I never did but I never could.  Add some nose weight, shorter lines?  The only wind changes I am used to making are the needle valve and the length of the prayer offered ahead of the 1st turn in the reverse wing over.  What is even funnier is that I will most likely be flying Expert.  Hey, placing last is still placing isn't it, and it is safer when your wife threatens you with divorce if you bring home another trophy.

Here is the irony.  I always trimmed my planes in a 15mph or so wind "back in the day" since fields trimming was really difficult then.  Of the 4 times I have been able to get out there since I got a couple of planes built it has been 0 and dead, 0 and almost dead, 10-15 with the wrong plane and 5 blowing directly into the sun.  So it is trimmed now for virtually no wind and flying great (better than the pilot which is all we can ask).

Any advice will be appreciated and feel free to laugh if you want.  I am embarrassed enough to have to even ask but I will have at best one warm up flight to set the plane up for winds that will probably be 5-10mph greater when my turn comes up.  Everything I read on the subject assumes you have unlimited flights to "play with it" using  "do this until it does that" changes.

My gut tells me to move my leadouts back 1/2" and start the prayer on the 3rd level lap instead of the 4th.

FYI - Right now my leadouts (3/4" spacing) are centered 7/8" behind the C/G which is ever so slightly tail heavy - where I like it.  OS46LA ,11-5 prop, 54oz, 63' .015 lines.

Thanks - Ken
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Offline john e. holliday

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Re: Wind Trim Adjustments
« Reply #1 on: June 07, 2018, 12:14:52 PM »
Being here in KANSAS flying when there is no wind is some times rare.   I have flown planes in contests that were comfortable to me to fly even when there is no wind.   I have even flown when I wondered if the lines were going to hold on the down wind side. D>K
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Online Dave_Trible

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Re: Wind Trim Adjustments
« Reply #2 on: June 07, 2018, 01:34:33 PM »
I would suggest very little if any change.  The most I typically might do in really bad wind is put in an extra 1/8-1/4 ounce tip weight.  Anything more and the whole airplane will be out of trim.  Never move your lead outs more than about 3/32-1/8”at a time!  Don’t screw the needle in unless you were flying too slow to begin with.  Just go fly it.  Try to fly more in a little breeze to learn how to handle it better.  When you attempt many drastic changes you are creating something you won’t be able to work with or adapt to in a flight or two- dance with the one who ya brung.

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Offline Ken Culbertson

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Re: Wind Trim Adjustments
« Reply #3 on: June 07, 2018, 02:22:28 PM »
I would suggest very little if any change.  The most I typically might do in really bad wind is put in an extra 1/8-1/4 ounce tip weight.  Anything more and the whole airplane will be out of trim.  Never move your lead outs more than about 3/32-1/8”at a time!  Don’t screw the needle in unless you were flying too slow to begin with.  Just go fly it.  Try to fly more in a little breeze to learn how to handle it better.  When you attempt many drastic changes you are creating something you won’t be able to work with or adapt to in a flight or two- dance with the one who ya brung.

Dave
I am pretty much in agreement.  No matter how I try, the wind won't cooperate.  My trim norm after the real basics is to get it over 45 in about 15mph and make it behave up there. Then I go to the balancing stuff.  This time around I couldn't buy wind to trim in so all I have is a plane that flies great in calm conditions.  If they are trimmed for wind they usually fly fine without it.  I just hope the reverse is true.  I may add 1/4oz to the tip.  I haven't changed tip weight since going from 62 to 63' lines.  They are the new copper ones and I was told that they were actually lighter that the steel ones.  I do know they have less rake in flight and have considerably less stretch but none of that screams out for more tip weight.  So all that is left is the length of the prayer before the RWO.

Ken
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Offline Randy Cuberly

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Re: Wind Trim Adjustments
« Reply #4 on: June 07, 2018, 04:34:00 PM »
I would never suggest trying to trim and airplane in 15 mph wind...It's impossible to tell what is really wrong with the trim under those circumstances.

An airplane properly trimmed under 2 to 6 mph conditions will fly as good in wind as the wind allows.

As stated above Never make drastic corrections to an airplane that flies well under normal conditions just because the wind is making it do strange things.  It will then simply do strange things under normal conditions, as well as windy conditions!

Randy Cuberly
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Online Howard Rush

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Online Trostle

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Re: Wind Trim Adjustments
« Reply #6 on: June 07, 2018, 06:21:51 PM »

(Clip)

---- and start the prayer on the 3rd level lap instead of the 4th.

Thanks - Ken

I am not sure what you mean about starting the "prayer on the 3rd level lap..."

If you are talking about starting the wingover to start your official flight, then the rules will require that you flight at least 5 laps from your takeoff point before you start the reverse wingover.  That includes the takeoff lap from where the takeoff started, then the two laps of judged level flight, then the requisite two "nominal" between the end of the third lap after takeoff and and the start of the reverse wingover.  Otherwise, you loose pattern points.

Another way to look at the required number of laps between the takeoff starting position and the reverse wingover is just think that you need to fly past the judges at least five time before you start the reverse wingover, regardless of where you start the takeoff.

Now, if you were talking about something else, disregard all of the above.

Keith

Online Paul Walker

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Re: Wind Trim Adjustments
« Reply #7 on: June 07, 2018, 07:19:12 PM »
Generally, the trim should be the same from calm to 20+ wind.

What you don't want to do is fly too slow in the wind hoping to keep the speed up in consecutive maneuvers down. Do make sure you have enough speed to get through the overhead eight.

A lower pitch prop will help the plane to resist speeding up in the consecutive maneuvers. That is another option to consider. Best thing is it will work in the light air also.

Good luck!

Offline Ken Culbertson

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Re: Wind Trim Adjustments
« Reply #8 on: June 07, 2018, 07:24:32 PM »
I am not sure what you mean about starting the "prayer on the 3rd level lap..."

If you are talking about starting the wingover to start your official flight, then the rules will require that you flight at least 5 laps from your takeoff point before you start the reverse wingover.  That includes the takeoff lap from where the takeoff started, then the two laps of judged level flight, then the requisite two "nominal" between the end of the third lap after takeoff and and the start of the reverse wingover.  Otherwise, you loose pattern points.

Another way to look at the required number of laps between the takeoff starting position and the reverse wingover is just think that you need to fly past the judges at least five time before you start the reverse wingover, regardless of where you start the takeoff.

Now, if you were talking about something else, disregard all of the above.

Keith

Sorry about the confusion.  The "Prayer" was referring to what you are doing in those laps before you point the nose of your new creation straight up for the 1st time and expect it to cross roughly 60' over your head in a 15mph wind.  Especially if you can't afford an engine that has more horse power than your lawnmower!  After it has done it once you can stop holding your breath and go back to normal breathing.

However, I refuse to disregard the above.  Saturday is my first contest since I had to quit back in the early 80's.  I was actually just reading the judges guide on that very point before joining the forum.  Your explanation is far better - Thanks.  When I last flew in front of judges you gave a hand signal.

Ken
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Offline Ken Culbertson

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Re: Wind Trim Adjustments
« Reply #9 on: June 07, 2018, 08:28:35 PM »
Generally, the trim should be the same from calm to 20+ wind.

What you don't want to do is fly too slow in the wind hoping to keep the speed up in consecutive maneuvers down. Do make sure you have enough speed to get through the overhead eight.

A lower pitch prop will help the plane to resist speeding up in the consecutive maneuvers. That is another option to consider. Best thing is it will work in the light air also.

Good luck!
Thank you for the advice.  In preparation I reread your "Flying Lines" article on flying in wind.  In fact, it was that article that prompted this thread.  I rarely touch the trim on a plane once it is trimmed.   I just learn fly it.  I never got to fly this one in any real wind so I don't know for sure if I have the right leadout position or prop.  I know this is heresy to some but I like to make my first few flights in about 10-15mph.  I want to know if I have serious, get out the X-Acto type issues, a funky tank setup or the wrong line length. I don't really know that till I get it overhead in wind.  I want to know that it will do a wingover, an overhead 8, 1st loop of the clover, top of the hourglass.  Not pretty, just do them.  Unless there is a "back to the shop" issue we start with the real trimming.  I am probably still stuck in the 80's  but it works for me.  Still not used to having more horsepower than my lawnmower.

Thanks again - Ken
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Offline Ken Culbertson

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Re: Wind Trim Adjustments
« Reply #10 on: June 08, 2018, 01:18:27 PM »
Thanks to everyone for calming my nerves.  I am not going to touch a thing and just go out there and have a blast placing last! (but not for long)

Ken
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If it is not broke you are not trying hard enough.
USAF 1968-1974 TAC

Offline M Spencer

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Re: Wind Trim Adjustments
« Reply #11 on: June 09, 2018, 07:12:28 AM »
I find at what I estimate 18 knots / mph , approx .

Where the rolling air is starting to overpower thye flight ,
Less Prop so the engine can kick in more up in the powerband , keeps more thrust over the control surfaces for control authority ,
and stops the aircraft going backwards , or thereabouts .

Maybe 3/4 less dia , of a inch or two less pictch .

Whatever , the engine needs to ' do its stuff ' , so say 5 % more Nitro , ( to 15 or 20 % ) can get you home free in coastal ' good sailing weather ,
When the Whitecaps are on the waves , & or kite boards are flying .

being   S M O O T H  into the Clover , ( Jim Manall found you needed to wingover from upwind in pommy gales , into the first clover loop from the vertical dive
as sometimes from level the wind pressure at entry hight overpowers things . This was with a Merco 35 Nimrod .

Othe ' Watch Yr R's is top hourglass corners , Smooth and round , not to hard / dont slam it on , or the first top corner the tail pushes out and the aeroplane disapears behind your right ear , lines loose , motor lean from the hard turn ,

Smooth the corners out and feel it round the urve ( Fly the corner , dont ' HIT the control ' full on ' inststantly .

Theyre the two , run like billyo to catch the lines tight . and as its gone upwind , get the nose turned flat ( inverted  ) not Nose up , or its ( the plane ) in and off , again .
wind lifting it inverted across at you . A 2 kilo plane youll wonder why you didnt bring a hard hat , when its snapped out of your sightline .


Theyre the only two heart in mouth places . Timing and entrys can take a bit of work . I think Mannals Wind Flying ' fly the schedule is on Dave Days site , now preserved by WINDY Notnowski .

Good Clean Phun , a bit more phisical in the blustery weather . at sea level - non summer the barometer can be Down  & the atmoshenere dense , so it can pack a punch .

The Olde Drawing your arm in , to keep control authority , in places . may help . Like pulling it down & around into the wind in the overheads . Some planes like / use the power of the air .
A featherweight isnt the best option , but giving the odd tug to assist the momentum can avoid speed loss in a good few places . Hence the ' Like Fishing & Flying a Kite ' analogy .
( at the Handle ) .

Can help to be limbered up , if it looks like it might be Quickening Your Pulse .  ;D H^^

Also a ligt T Shirt , and for Long Hairs a pony tail , lets you sense the direction etc on the back of your neck & arms , and stay away from trees , in case the blow over . ( Just Kidding on That . )
tho rolling wakes  and downdrafts downwing from air pulling tru below the folliage will pull the plane aroud , so Large obstruction disrupt smooth air . Just Plain steady nice wind isnt bad .

Spelinks Off . And Um , Lap Time say 4.8 on yr Avg Model , Down to 4.5 heavy plane blustery wind gusting 20 / 25 + . Helps .
« Last Edit: June 09, 2018, 07:48:30 AM by Matt Spencer »

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