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Author Topic: Tweaking Flaps  (Read 16306 times)

Offline pmackenzie

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Re: Tweaking Flaps
« Reply #50 on: January 01, 2021, 12:08:15 PM »
I have high C/G problem in my Max Bee. Wing is kind of low, battery is all the way up.
Igor confirmed that he puts his battery this way( I also saw it for myself), so I just kept tweaking the flaps till it flew flat.
Which it does now and has no line tension problems anywhere, but I still wonder if this is the best way.

If I had a repeatable adjuster I would be more likely to try putting the battery in lower, and un-tweaking the flaps.
Next one might :)

Pat MacKenzie
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Offline Chuck_Smith

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Re: Tweaking Flaps
« Reply #51 on: January 02, 2021, 08:39:32 AM »
I have no idea how much can be tolerated, but as a rule it's never good to fix one fault with another.
I guess the fundamental problem is that aerodynamic claptraps react exponentially to speed changes, when static CG effect changes in a linear way. That way you can acchieve a harmonic balance only in a very narrow speed range. Yes, allmost everything can be trimmed to work well but still all these little things make the model more logical and predictable to trim and fly. Or at least they give you a peace of mind😂. L

Lauri, I would tend to argue that CG change effects are second order, as are aerodynamic effects. Also, since no flying airplane that didn't leave the atmosphere was ever in a truly static condition, that mass and aero effects due to control surface deflections will be forever coupled.

Peace,

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Offline Chuck_Smith

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Re: Tweaking Flaps
« Reply #52 on: January 02, 2021, 09:34:01 AM »
Yes, Chuck. My wording was bad.
But still, it’s never a good idea to compensate one fsult with another. L

Clearly, you've never had to deal with the aero guys on a Formula 1 car!

Seriously, no problem friend.  I like your posts.


Peace,


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Online Howard Rush

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Re: Tweaking Flaps
« Reply #53 on: January 02, 2021, 11:52:55 PM »
Here are pins soldered into the control horn arms.  I looked for several days for my Stay Brite flux, but couldn't find it, so I used ordinary solder.
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Online Howard Rush

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Re: Tweaking Flaps
« Reply #54 on: January 03, 2021, 09:55:20 PM »
And those bearing blocks look like the mother of all overkills🙃. Did you make them or buy ready?

Tony Huber made the aluminum blocks.  I pressed Igus bushings into them.

I like the idea of one mounting plate where all are fixed before final assembly.

Me, too.  That's Paul Walker's idea.

Any idea of the flap root dimensions yet?

Here are some pictures.  Sorry about the dimensions.  I don't know how to change them to mm in TurboCad. 

Control horn slides into a carbon pocket at the end of the flap.  Typically I make the pocket just fit the control horn, but here I've allowed for +/- 3 degrees of control horn rotation.  The adjuster pin fits in a slot at the bottom of the pocket.  The adjustment mechanism would be outboard of the pocket in a chunk of balsa or harder material as required.  The pocket is attached to the flap leading edge torque tube and short aluminum doubler tube (blue in the pictures).

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Online Howard Rush

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Re: Tweaking Flaps
« Reply #55 on: January 03, 2021, 10:13:59 PM »
Here is a cutaway drawing.

I see we can post dxf files, but I can't get the dxf file less than a MB.
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Online Howard Rush

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Re: Tweaking Flaps
« Reply #56 on: January 04, 2021, 12:18:50 AM »
Here are the dimensions.  I can email you the .dxf  if you like. 

The mechanism can protrude above the flap surface.

Thanks.
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Online Howard Rush

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Re: Tweaking Flaps
« Reply #57 on: January 04, 2021, 11:52:07 AM »
Yes. 3.175 mm according to Alexa.
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Online Ken Culbertson

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Re: Tweaking Flaps
« Reply #58 on: January 04, 2021, 11:56:00 AM »
Here is my entry in the sweepstakes.  It's a poor man's version of Paul's design.  It is drawn to show the inboard flap adjustable but it would be made to have the outboard adjustable.

You could also flip the adjustable horn and put a slot on the elevator linkage and use the ball link bolt to adjust both flap and elevator.  However keeping one setting in line while adjusting the other might result in your accidently dropping your stooge on the inboard wing from 6'. LL~

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Online Howard Rush

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Re: Tweaking Flaps
« Reply #59 on: January 04, 2021, 10:54:32 PM »
Your flaps are very skinny, Howard. Remaining perfectly aesthetic, the adjustment could be +/-2ish° each flap. Is that enough? After that, it gets bumpy.

Bumpy is acceptable.  I'm trying for +/- 3° and only putting the device on the right flap. 

I now have ideas about how to make the adjuster.  I am slowly drawing them.  I want both the adjuster and the control horn pocket to be capable of reacting the flap hinge moment.  This complicates the design a little.
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Offline Bruce Shipp

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Re: Tweaking Flaps
« Reply #60 on: January 05, 2021, 06:56:15 AM »
Howard, that looks very nice but much more complicated than Paul’s original system in this thread. What are he advantages of your system over Paul’s original? My first guess is that Paul’s dual flap horn system is not easily incorporated into the Logarithmic control system. Correct? Any other advantages? 

Thanks,

Bruce

Online Ken Culbertson

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Re: Tweaking Flaps
« Reply #61 on: January 05, 2021, 10:37:09 AM »
...dual flap horn system is not easily incorporated into the Logarithmic control system.... 
Actually it could be but it is a lot of work with the dual tracks.  I am in the process of machining this one for my Trifecta profile.  It will not be flight tested till about March but I see no reason that it will not work.

Ken
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Online kevin king

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Re: Tweaking Flaps
« Reply #62 on: January 08, 2021, 01:11:12 AM »
Like with many things, it's easy to find a complicated solution, but you need a genius to come up with a simple and elegant one. L
Windy Urtnowski had a simple fix for tweeking 1/8" horns. Removable flaps. He removed the hinge pins and ran a piece of music wire out past the last hinge on the wing tips and bent an 'L' in the end of it, which was then sunk into an L shape trough and covered with a piece of tape? Or it could have been a brass eyelet in the TE.

Online Howard Rush

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Re: Tweaking Flaps
« Reply #63 on: January 08, 2021, 03:14:13 AM »
Windy Urtnowski had a simple fix for tweeking 1/8" horns. Removable flaps. He removed the hinge pins and ran a piece of music wire out past the last hinge on the wing tips and bent an 'L' in the end of it, which was then sunk into an L shape trough and covered with a piece of tape? Or it could have been a brass eyelet in the TE.

I do that with my .031" hinge pins, but it doesn't get the control horn tweaked. 
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Online Howard Rush

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Re: Tweaking Flaps
« Reply #64 on: January 08, 2021, 03:15:07 AM »
Howard,

If you drill new holes 1" from hingeline, +/-3° will fit nicely. And, you could still try to find your Staybrite. L

Alas, the control horn assembly is part of the fuselage now. 
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Online Howard Rush

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Re: Tweaking Flaps
« Reply #65 on: January 08, 2021, 03:30:35 AM »
Howard, that looks very nice but much more complicated than Paul’s original system in this thread.

Probably so.  It makes more sense, but not enough, if you look at the sequence. 

2014 airplane:
1. I think I have a better idea than Paul's-- similar to Ken's, but more complicated.  I get parts made.
2. I fiddle with the device for a week, but can't get the bind out.
3. I realize that the bind is designed in.  It's too late to do something else, so I revert to a standard control horn.

2020 airplane:
1. I think I have a better idea than Paul's.  Inspired by Chuck and Lauri, I decide to build the adjuster into the flap.  Looks simple.
2. Find out it's not simple.  By then I have a standard control horn built into the airplane with 1/16" thorns sticking out. 
3. I'm working on it.

« Last Edit: January 08, 2021, 03:48:26 AM by Howard Rush »
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Online Howard Rush

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Re: Tweaking Flaps
« Reply #66 on: January 08, 2021, 03:47:03 AM »
Actually it could be but it is a lot of work with the dual tracks.  I am in the process of machining this one for my Trifecta profile.  It will not be flight tested till about March but I see no reason that it will not work.

Initially, I thought it was too adjustable.  If you have a good 3D control geometry program, you could dispense with the slots in the tops of both bellcranks.  Then I decided it was really clever.  You could find out how much flap travel you need, then set slot 5 to give full bellcrank travel for that much flap.  I figured I had a better idea, of course.  I would find out how much flap travel I need from the flight data recording, then drill the hole in the new airplane's bellcrank in the right place.  The trouble with that is that it's too late to put a control surface deflection measurer in the old airplane.  I have provisions for it in the new airplane, but I'd first have to drill the hole in the bellcrank to fly the airplane to get the data. 

Also, it would probably be good to be able to adjust the bellcrank-to-flap ratio for flying in different density air,.
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Online kevin king

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Re: Tweaking Flaps
« Reply #67 on: January 08, 2021, 12:23:50 PM »
I do that with my .031" hinge pins, but it doesn't get the control horn tweaked.
Unless I'm missing something, removing the flaps leaves the 1/8" horns exposed. A pair of pliers on each horn allows them to be tweaked...
 

Online Ken Culbertson

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Re: Tweaking Flaps
« Reply #68 on: January 08, 2021, 01:15:47 PM »
Unless I'm missing something, removing the flaps leaves the 1/8" horns exposed. A pair of pliers on each horn allows them to be tweaked...
My experience has been that tweaking results in over tweaking or breaking a flap.  That is why I use tabs which look like crap.  Removing flaps at the field is not where I want to go either.  So I am for adjustable wherever and whenever you can build it in.  My goal is to have everything flap related adjustable from a well placed side hatch.  Besides, it is winter which is tinker time!

ken
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Online Ken Culbertson

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Re: Tweaking Flaps
« Reply #69 on: January 08, 2021, 02:37:59 PM »
It'll be not necessary to remove wing(s) at field (even though it's not a big deal, just unscrewing 3 bolts. I do it all the time).
I know this kind of mechanics pretty well, and you can tighten the setscrew snugly, you can still turn it but it'll stay in place during flight. When you're done, remove wing(s) and do the final tightening with 1 M2 screw. L
Most of us here do not use removable wings.  I have had 2 over the years and I agree, it is no big deal and it does give you access to the flap linkages but I am not going to Worlds any time soon so I will keep them in one piece.

Ken
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Online Howard Rush

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Re: Tweaking Flaps
« Reply #70 on: January 08, 2021, 04:54:24 PM »
Unless I'm missing something, removing the flaps leaves the 1/8" horns exposed.

And I have a pair of 1/4” aluminum bars with 1/8” holes in the ends with which to tweak them.   This is handy for the first flight or two of the airplane, but after that I’d have to untape the flaps to remove them, which is a bother.
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Offline Wolfgang Nieuwkamp

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Re: Tweaking Flaps
« Reply #71 on: January 10, 2021, 01:59:07 PM »
Lauri,

should the M2 locking screw be rotated 90°, so you can acces that screw after adjusting?

Regards,

Wolfgang

Offline pmackenzie

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Re: Tweaking Flaps
« Reply #72 on: January 10, 2021, 02:56:23 PM »
If you rotate the whole assembly 90 degrees, then the screw could be accessed through a small hole in the back of the flap.
It would also move the slot for the pin away from the clamp part, which might be better structurally.
The mounting bolts might be  problem  though in this arrangement....
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Online Ken Culbertson

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Re: Tweaking Flaps
« Reply #73 on: January 15, 2021, 11:10:51 AM »
Just an RCH.  I specified a 1/4" slot, which was made very accurately for the 1/4" bearing.  That was too tight.  Mike Haverly told me that it's easy to make it just right using a file.  It actually was.
Howard, this is my first adventure into milling since 1974.  I learned/remembered a bunch and actually did not have to trash my first part!  No end to the uses that cheap mill will have now!

I tried covertly to find the thickness of a RCH but failed.  A BCH would be either too thick or too thin.  This is for my profile so I am not wasting the 1/4" bearings you suggested.  This uses a 4-9-2.5.  The "slop" is slightly less than .005.  Is that too much?
Will lightening it with the cutouts and holes in the second and third drawings hurt?  I used 1/16" steel so it is pretty strong.  Shame you can't laser print steel.

Ken
« Last Edit: January 15, 2021, 11:33:05 AM by Ken Culbertson »
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Offline Wolfgang Nieuwkamp

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Re: Tweaking Flaps
« Reply #74 on: January 15, 2021, 11:32:42 AM »
Hello Ken,

you can laser print steel, Selective Laser Melting (SLM). But it is expensive!
Regards,

Wolfgang

Online Ken Culbertson

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Re: Tweaking Flaps
« Reply #75 on: January 15, 2021, 11:53:55 AM »
Hello Ken,

you can laser print steel, Selective Laser Melting (SLM). But it is expensive!
Regards,

Wolfgang
Cheaper to have a die made and stamp them.  Cheaper yet to DYI with a cheap mill and a good file!

Ken
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Online Howard Rush

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Re: Tweaking Flaps
« Reply #76 on: January 15, 2021, 04:36:12 PM »
Howard,

 This is how I'd do it. Sorry for the drawing. It's designed to fit inside your flap without a bump. It should give the +/-3° adjustability you required. But still, please consider having it in both flaps..
 There is a minor f**kup in the plan, for some reason I remembered that the pin ø in horn is 2mm. But actually that's great, it'll be slightly stronger and more compact with 1/16" pins. Also, the distance between pin CL and hinge line should be 1".
I drew it all rectangular, the idea is to file it conical as per flap cross section when it's in place before sheeting the flap. But if I did it (wink wink), I could as well mill it conical.
 I would clamp the thing between 2 gf or cf ribs, with epoxy & countersink M2 bolts. Then fill all empty space between ribs with balsa. See the bad assembly drawing.
It looks much more complex than it is. I'd estimate 1 hour work with lathe & mill per unit.

Thanks, Lauri.  That looks better than what I was thinking.  I'm not averse to having an Allen key slot in the flap to tighten the wee screw.  I was considering putting access holes through the fuselage until I remembered that there is a flap in the way on the opposite side. 
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Online Brett Buck

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Re: Tweaking Flaps
« Reply #77 on: January 16, 2021, 12:55:04 AM »
Just an RCH.  I specified a 1/4" slot, which was made very accurately for the 1/4" bearing.  That was too tight.  Mike Haverly told me that it's easy to make it just right using a file.  It actually was.

    For one-off parts, there are very few things you can't make accurately with a file and other hand tools. It takes much longer and much more skill but most apprentice machinists learned first to make things with files and saws, then, move on to milling machines and lathes.

    More or less everything I have ever done was done that way, not that I particularly look forward to it, but I have made some pretty precise parts (like an emergency replacement for Sergei Belko's broken ball link, including *metric* threads with all hand tools I had in my regular toolbox, and under and hour, from a phone description).

    Brett

Offline Paul Walker

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Re: Tweaking Flaps
« Reply #78 on: January 16, 2021, 03:08:36 PM »
Have enjoyed reading all the responses to Alan's initial post.

I think some have missed the point. The method I use is simple, and reasonably light, AND is precise and repeatable. Tweaking a flap horn is less that precise, and very difficult to get a 0.2 degree change in flap angular relationship.  My system solves all the issues I have had over the years with tweaking or tabs.

Online Howard Rush

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Re: Tweaking Flaps
« Reply #79 on: January 16, 2021, 06:52:52 PM »
And as with other things, thinking I could come up with a better solution has proven troublesome.
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Online Brett Buck

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Re: Tweaking Flaps
« Reply #80 on: January 17, 2021, 12:24:33 AM »
And as with other things, thinking I could come up with a better solution has proven troublesome.

  That's what you get for thinking.

    Brett

Online Ken Culbertson

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Re: Tweaking Flaps
« Reply #81 on: January 18, 2021, 12:31:01 PM »
And as with other things, thinking I could come up with a better solution has proven troublesome.
I plan to do it the old fashioned way.  Re-invent somebody else wheel. H^^  LL~

Seriously though I don't see any way to pull it off and still have the flaps removable without splitting the flap horn unless you have 3/8" or thicker flaps.  Paul's method is probably the best available and I can assume that the small amount of differential that it adds is actually good but it would require a lot of work and accuracy to use it on logarithmic horns.  Keith's method on the other hand will work just fine but does not offer the same ease to make very small adjustments.  That brings me to what you are working on.  I eagerly await a finished product so that I can invent one just like it! LL~

Ken
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Offline Craig Beswick

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Re: Tweaking Flaps
« Reply #82 on: January 18, 2021, 04:25:39 PM »
Have enjoyed reading all the responses to Alan's initial post.

I think some have missed the point. The method I use is simple, and reasonably light, AND is precise and repeatable. Tweaking a flap horn is less that precise, and very difficult to get a 0.2 degree change in flap angular relationship.  My system solves all the issues I have had over the years with tweaking or tabs.

Hello Paul,
is your method diagrammed somewhere? I have your 2016 column, from Flying Lines, but only one picture comes up of the completed mechanism. You refer, in your article, to other, "Figures" and "Photos" that are not on the page I can view.

Regards
Craig Beswick
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Offline Dennis Nunes

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Re: Tweaking Flaps
« Reply #83 on: January 18, 2021, 05:49:33 PM »
Hello Paul,
is your method diagrammed somewhere? I have your 2016 column, from Flying Lines, but only one picture comes up of the completed mechanism. You refer, in your article, to other, "Figures" and "Photos" that are not on the page I can view.

Regards
Craig Beswick
Hi Craig,

I put together a document entitled, “Turning to the Dark Side – The Building of Circulas 46 IIe”. This is an electric profile that uses the Walker Flap Adjuster Device (WFAD). The PDF document can be downloaded at: http://flyinglines.org/nunes.circulas46lle.html

“Chapter 4 – Controls System” starting on page 37, shows the control system including how I made my WFAD. Hope this helps.


Dennis

Offline Craig Beswick

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Re: Tweaking Flaps
« Reply #84 on: January 18, 2021, 06:14:46 PM »
Thank you Dennis,
just what I was looking for.

Fantastic build feature!!!

Craig
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Offline Paul Walker

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Re: Tweaking Flaps
« Reply #85 on: January 18, 2021, 08:21:38 PM »
Here is a photo from the first P-47.

Note that this is NOT the final adjustment position for the mechanism. It is in the assemble stage at this point. The inboard horn goes forward, the outboard aft  them the bolt threads into the clevis and then drawn into the flaps level position. I have blocks that fit under the horns to check that both horns are in the same plane.  Hope this helps.

Offline Craig Beswick

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Re: Tweaking Flaps
« Reply #86 on: January 18, 2021, 09:18:43 PM »
Thanks Paul,
I couldn't work out what was going on inside the black box/captive area. Nothing, as it turns out just a bolt inside a sleeve.

Thanks once again
Craig
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Online Ken Culbertson

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Re: Tweaking Flaps
« Reply #87 on: January 22, 2021, 10:54:40 AM »
Step 1 for the adjustable logarithmic.  Step 2 is to have my head examined.  I was surprised how firm it is with just the single tightening screw.  Hope it is worth the extra weight.  Wish I had the machining tools some of you have.  FYI the bulges where a well trained brazer would have made this look spiffy are from adding a pin into the drive arm so that I could use solder to make it.

1/4" flap adjustment at the TE each way.  If it needs that much then the wing is crap.

Ken
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Online Ken Culbertson

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Re: Tweaking Flaps
« Reply #88 on: January 23, 2021, 11:46:42 AM »
That's how the first one came out. It should fit inside Howards flap and have the required adjustability range.
Tightening works like a treat.
The distance between hinge line and 1/16" pin should be 1". L
I love it. #^  That is one piece that will not go into the trash if the plane gets totaled! y1
I only wish I had the tools.

Ken
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Online Howard Rush

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Re: Tweaking Flaps
« Reply #89 on: January 25, 2021, 10:06:45 PM »
That's how the first one came out. It should fit inside Howards flap and have the required adjustability range.
Tightening works like a treat.
The distance between hinge line and 1/16" pin should be 1". L

Very nice, Lauri.
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Online Ken Culbertson

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Re: Tweaking Flaps
« Reply #90 on: January 26, 2021, 03:08:13 PM »
Finished product.   With good drilling and milling equipment (which I don't have) this is a simple project.  Without them it is a day with your favorite files.  I have made it adjustable.  I can see a need to have the flap drive arm different lengths till I decide on the ratio I want.  Then I will probably make it fixed.  Probably could use smaller bearings as well.

Ken
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Online Ken Culbertson

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Re: Tweaking Flaps
« Reply #91 on: January 27, 2021, 01:24:58 PM »
Ken,

I think the flap horn looks too weak, too little material around the bearing groove. I wouldn't save grams there.

A point well taken. However it is high grade steel.  I have put a lot of pressure on it and it doesn't bend.  Future ones will be thicker because I will be using a smaller bearing.  I used too large a mill to cut the slot and I had to widen it for a larger bearing.   Next one will have an undersized slot that I file to fit the bearing and will be 1/8 over the slot.. Right now it is actually thicker that one of Morris's adjustable horns and larger that the drawings Igor published.

Once I get my shop up and running again I will be brazing instead of having to use cheater pins so that I can solder the horn.  The main reason I built this one is to mount it on a test stand.  It may never see a live flight.   

Ken
AMA 15382
If it is not broke you are not trying hard enough.
USAF 1968-1974 TAC

Offline Alan Resinger

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Re: Tweaking Flaps
« Reply #92 on: January 28, 2021, 10:20:14 AM »
I am really curious as to how much this unit weighs?

Online Ken Culbertson

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Re: Tweaking Flaps
« Reply #93 on: January 28, 2021, 11:32:39 AM »
I am really curious as to how much this unit weighs?
Unfortunately I lost my scale in last year's fire but I have one on order.  As soon as I have one I will weigh it.  My SWAG is about double a heavy duty standard horn. It can be made lighter, especially if I could have brazed the joints instead of reinforced solder. However, I am not concerned with the weight due to the way I build.  For whatever reason I almost always come out nose heavy and have to add tail weight.  It is such a regular thing that I even build in a tail weight box just like a tip weight one.  The whole gizmo is well aft of the CG.  Right now I am making a test stand to evaluate the movement.

Ken
AMA 15382
If it is not broke you are not trying hard enough.
USAF 1968-1974 TAC

Online Howard Rush

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Re: Tweaking Flaps
« Reply #94 on: January 28, 2021, 02:39:11 PM »
Ooh.  Ooh.  Splendid.  Thank you.  Can I send you something in return?  Some cheese with no holes?
The Jive Combat Team
Making combat and stunt great again

Offline Lauri Malila

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Re: Tweaking Flaps
« Reply #95 on: March 05, 2022, 02:17:39 AM »
...
« Last Edit: January 04, 2023, 11:05:14 PM by Lauri Malila »

Online Howard Rush

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Re: Tweaking Flaps
« Reply #96 on: March 05, 2022, 03:13:09 AM »
Here's Lauri's tweaker in my flap. 
The Jive Combat Team
Making combat and stunt great again

Offline Lauri Malila

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Re: Tweaking Flaps
« Reply #97 on: March 05, 2022, 03:36:26 AM »
...
« Last Edit: January 04, 2023, 11:04:50 PM by Lauri Malila »

Offline Matt Colan

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Re: Tweaking Flaps
« Reply #98 on: March 05, 2022, 07:17:37 AM »
One thing I’m trying to figure out with the WFA, is to also be able to adjust the elevator pushrod. My current plane has the adjustable pushrod and I’m a huge fan of it to get my neutral just right, adjust inside/outside turn, inside/outside corner presentation etc. i realized recently while building an airplane for someone else when I installed the WFA, I can’t adjust the pushrod length because it’s bolted to the other flap horn.

So right now im at a crossroads for my next airplane…either have an adjustable pushrod and don’t include the WFA and use a trim tab again, or the WFA without an adjustable pushrod in the back. Hmmmmm…
Matt Colan

Offline Lauri Malila

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Re: Tweaking Flaps
« Reply #99 on: March 05, 2022, 08:21:32 AM »
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« Last Edit: January 04, 2023, 11:04:32 PM by Lauri Malila »


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