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Drooping FireFly Flaperons
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jbhart(at)onlyinternet.ne
Guest

Posted: Sun Jul 20, 2008 7:09 am Post subject: Drooping FireFly Flaperons

Kolbers,



Yesterday, I flew to Hagerstown to my EAA 373 Chapter meeting.  I lifted off 

into the morning haze and did not climb above 1,000 feet agl to maintain 

some horizontal visual range.  I had a 15 mph head wind so I let the engine 

run on up to make time.  It took me 40 minutes to fly 26 miles or 39 mph 

ground to ground.  On the way home the haze had not improved.  I throttled 

back to 5,000 rpm so I would not get home too soon.  One of the fun things 

about the FireFly is to just be up in the air, to build time and to ride the 

thermals.  It took 28 minutes to get home or 57 mph ground to ground.  



On the way home, I flew at an 40 mphi.  Since the FireFly is trimmed out for 

the engine running 5,500 rpm, I had to hold considerable back pressure.  And 

then the light bulb went off.  I cranked in about one degree of flaperon.  

The nose came down, the back pressure requirement disappeared, indicated and 

ground speed picked up little and engine rpm increased enough so that I had 

to throttle it back a little with no loss of altitude.  These continuously 

adjustable flaperons are just great for trimming to maintain a low drag 

configuration.



Fly Safe.



Jack B. Hart FF004 

Winchester, IN



do not archive

John Hauck

Joined: 09 Jan 2006
Posts: 4639
Location: Titus, Alabama (hauck's holler)

Posted: Sun Jul 20, 2008 1:04 pm Post subject: Drooping FireFly Flaperons

Since the FireFly is trimmed out for

 	  Quote: 	
		   the engine running 5,500 rpm, I had to hold considerable back pressure. 

 And

 then the light bulb went off.  I cranked in about one degree of flaperon.

 The nose came down, the back pressure requirement disappeared, indicated 

 and

 ground speed picked up little and engine rpm increased enough so that I 

 had

 to throttle it back a little with no loss of altitude.  These continuously

 adjustable flaperons are just great for trimming to maintain a low drag

 configuration.



 Fly Safe.



 Jack B. Hart FF004


	




Jack H:



Maybe I am misunderstanding your comments.



Understand you "cranked in about one degree of flaperon."  Does that mean 

you drooped or reflexed them about one degree?



john h

mkIII

_________________
John Hauck
MKIII/912ULS
hauck's holler
Titus, Alabama

jbhart(at)onlyinternet.ne
Guest

Posted: Sun Jul 20, 2008 4:17 pm Post subject: Drooping FireFly Flaperons

John H.



Drooped



Jack B. Hart FF004

Winchester, IN



At 04:01 PM 7/20/08 -0500, you wrote:

 	  Quote: 	
		  



Jack H:



Maybe I am misunderstanding your comments.



Understand you "cranked in about one degree of flaperon."  Does that mean 

you drooped or reflexed them about one degree?



john h

mkIII

John Hauck

Joined: 09 Jan 2006
Posts: 4639
Location: Titus, Alabama (hauck's holler)

Posted: Sun Jul 20, 2008 4:41 pm Post subject: Drooping FireFly Flaperons

> Drooped

 	  Quote: 	
		  

 Jack B. Hart FF004


	




Hi Jack H:



That is what I thought.



Drooping flaperons or flaps pushes the nose down, requiring more aft 

pressure to remain level.



Reflexing them will pull the nose up, requiring less aft pressure, or if 

reflexed enough, you will then have to apply forward pressure on the stick 

to remain level.



This is the opposite effect you got?????



Wonder why your aircraft responded in an opposite manner?



john h

mkIII

_________________
John Hauck
MKIII/912ULS
hauck's holler
Titus, Alabama

Thom Riddle

Joined: 10 Jan 2006
Posts: 1597
Location: Buffalo, NY, USA (9G0)

Posted: Mon Jul 21, 2008 3:35 am Post subject: Re: Drooping FireFly Flaperons

Drooping the flaperons (or flaps) a bit increases the angle of attack a bit. The increased angle of attack results in a little more lift. The increased lift would result in a slight climb and loss of airspeed unless the pilot retrims, or in Jack's case, relaxes the back pressure. Relaxing the back pressure restores the angle of attack to its pre-droop state with a resulting slight nose down pitch. Thus the stabilized state is restored with less up elevator pressure. 



With larger amounts of flap application drag increases sufficiently to reduce airspeed. With a very small deflection, depending upon control surface rigging, the drooping flaps could result in slightly less drag and thus resulting in slightly higher airspeed. Since this happened on Jack's Firefly, I would venture a guess that the flaps full up configuration could benefit from a small adjustment toward a slightly more drooped condition to reduce drag. It is counterintuitive but many things are, and yet true, nonetheless. 



This effect can be quite different on different airplanes depending upon design and actual rigging, so this may or may not apply to your airplane but could apply to others. 



Our Allegro in flaps up configuration, the flaps are reflexed 4 1/2 degrees. This results in nearly 10 mph higher airspeed at Vh compared to 0 degrees of flap. Some airplanes get best Vh with zero degree flaps some with reflexed flaps, and it is conceivable that some get a higher Vh with slightly drooping flaps.

_________________
Thom Riddle
Buffalo, NY (9G0)

Don't worry about old age... it doesn't last very long.
- Anonymous

ez(at)embarqmail.com
Guest

Posted: Mon Jul 21, 2008 4:45 am Post subject: Drooping FireFly Flaperons

Tom,

Sounds good on paper, but I've never found a Kolb that has shown that  

behavior with flaps or flaprons.

Reflex always lifts the nose and flaps down always lowers the nose on  

all  the kolbs I have ever flown.



Gene



On Jul 21, 2008, at 7:35 AM, Thom Riddle wrote:



 	  Quote: 	
		   



 Drooping the flaperons (or flaps) a bit increases the angle of  

 attack a bit. The increased angle of attack results in a little more  

 lift. The increased lift would result in a slight climb and loss of  

 airspeed unless the pilot retrims, or in Jack's case, relaxes the  

 back pressure. Relaxing the back pressure restores the angle of  

 attack to its pre-droop state with a resulting slight nose down  

 pitch. Thus the stabilized state is restored with less up elevator  

 pressure.



 With larger amounts of flap application drag increases sufficiently  

 to reduce airspeed. With a very small deflection, depending upon  

 control surface rigging, the drooping flaps could result in slightly  

 less drag and thus resulting in slightly higher airspeed. Since this  

 happened on Jack's Firefly, I would venture a guess that the flaps  

 full up configuration could benefit from a small adjustment toward a  

 slightly more drooped condition to reduce drag. It is  

 counterintuitive but many things are, and yet true, nonetheless.



 This effect can be quite different on different airplanes depending  

 upon design and actual rigging, so this may or may not apply to your  

 airplane but could apply to others.



 Our Allegro in flaps up configuration, the flaps are reflexed 4 1/2  

 degrees. This results in nearly 10 mph higher airspeed at Vh  

 compared to 0 degrees of flap. Some airplanes get best Vh with zero  

 degree flaps some with reflexed flaps, and it is conceivable that  

 some get a higher Vh with slightly drooping flaps.



 --------

 Thom Riddle

 N221FA Allegro 2000 912UL

 N197BG FS1/447

 --------------------

 “Scratch any cynic,” he said, “and you’ll find a disappointed  

 idealist.”

 George Carlin





 Read this topic online here:



 http://forums.matronics.com/viewtopic.php?p=194082#194082

Thom Riddle

Joined: 10 Jan 2006
Posts: 1597
Location: Buffalo, NY, USA (9G0)

Posted: Mon Jul 21, 2008 5:10 am Post subject: Re: Drooping FireFly Flaperons

Gene,



That is what I said. 



"... a resulting slight nose down pitch..."

_________________
Thom Riddle
Buffalo, NY (9G0)

Don't worry about old age... it doesn't last very long.
- Anonymous

John Hauck

Joined: 09 Jan 2006
Posts: 4639
Location: Titus, Alabama (hauck's holler)

Posted: Mon Jul 21, 2008 5:17 am Post subject: Drooping FireFly Flaperons

> Sounds good on paper, but I've never found a Kolb that has shown that

 	  Quote: 	
		   behavior with flaps or flaprons.

 Reflex always lifts the nose and flaps down always lowers the nose on  all 

 the kolbs I have ever flown.



 Gene


	




Gene/Thom/Gang:



That has been my experience with Kolbs.  Sometimes their behavior is 

extremely unique, defying explanation and proof on paper.



Weight and balance of a Kolb is one of those unique areas.  There are folks 

out there still flying Kolbs with lead in the nose to make the paperwork 

work.  I put a 11+ lb tailwheel on mine for a couple reasons.  Primarily, 

the Maule Tundra Tailwheel, 8" pneumatic with tapered roller bearings in the 

pivot, is the only tailwheel I could afford that will stand up to the weight 

of the tail on my MKIII.  The other reason was to demonstrate Kolbs don't 

particularly have an aft cg problem, if built, more or less, according to 

the plans.  In addition to the heavy tailwheel and prop on a 4" extension, 

I fly with 150 lbs of fuel and 100+ lbs of cargo aft of the cg.  I do get 

some offset from my modified main gear being moved 8" forward, but not much, 

since they are very close to the cg.



I believe Jack H mentioned he drooped his flaperons about a degree.  I doubt 

that amount is even measureable in flight.  I work with 20 and 40 degrees of 

flaps.  When drooped, it is quite evident that something has changed.  



john h

mkIII

_________________
John Hauck
MKIII/912ULS
hauck's holler
Titus, Alabama

lucien

Joined: 03 Jun 2007
Posts: 721
Location: santa fe, NM

Posted: Mon Jul 21, 2008 5:37 am Post subject: Re: Drooping FireFly Flaperons

 	  ez(at)embarqmail.com wrote: 	
		  Tom,

Sounds good on paper, but I've never found a Kolb that has shown that  

behavior with flaps or flaprons.

Reflex always lifts the nose and flaps down always lowers the nose on  

all  the kolbs I have ever flown.



Gene



On Jul 21, 2008, at 7:35 AM, Thom Riddle wrote:



	
 



I've never flown a plane period with flaps that didn't do this. The increased AOA of additional flaps always had/has the effect of trimming the nose down, not up... 



My titan works the same way. In fact, when doing pattern work I leave the trim set to require some forward pressure on the stick when straight/level with no flaps. Adding the first ten degs. nulls it out nicely and full generally requires only a little back pressure (this is when I"m lazy and don't adjust the trim throughout like I probably should ).



As for the W&B, The original builder of my FS II added 10lbs of ballast to the nose a few hours after the first flight. It was kind of tail heavy without it mostly due to the use of the C box and clutch on the engine, which adds 10lbs over the B box at an arm pretty well behind the CG. 



Even so he said it flew fine, but it was just better with a little ballast.....



LS

_________________
LS
Titan II SS

herbgh(at)nctc.com
Guest

Posted: Mon Jul 21, 2008 6:18 am Post subject: Drooping FireFly Flaperons

all of this said...might be interesting to see a picture of your 

plane in cruise flight...Jack... Without the  skosh of 

flaperons...     I find that , as I recall you mentioning,  the 

Firefly is tiring on a trip of any length.... I attribute this to the 

inability of the pilot,me at my age and attention span , to keep the 

little bird on step.      Herb

At 08:15 AM 7/21/2008, you wrote:

 	  Quote: 	

 > Sounds good on paper, but I've never found a Kolb that has shown that

>behavior with flaps or flaprons.

>Reflex always lifts the nose and flaps down always lowers the nose 

>on  all the kolbs I have ever flown.

>

>Gene

Gene/Thom/Gang:

That has been my experience with Kolbs.  Sometimes their behavior is 

extremely unique, defying explanation and proof on paper.

Weight and balance of a Kolb is one of those unique areas.  There 

are folks out there still flying Kolbs with lead in the nose to make 

the paperwork work.  I put a 11+ lb tailwheel on mine for a couple 

reasons.  Primarily, the Maule Tundra Tailwheel, 8" pneumatic with 

tapered roller bearings in the pivot, is the only tailwheel I could 

afford that will stand up to the weight of the tail on my 

MKIII.  The other reason was to demonstrate Kolbs don't particularly 

have an aft cg problem, if built, more or less, according to the 

plans.  In addition to the heavy tailwheel and prop on a 4" 

extension, I fly with 150 lbs of fuel and 100+ lbs of cargo aft of 

the cg.  I do get some offset from my modified main gear being moved 

8" forward, but not much, since they are very close to the cg.

I believe Jack H mentioned he drooped his flaperons about a 

degree.  I doubt that amount is even measureable in flight.  I work 

with 20 and 40 degrees of flaps.  When drooped, it is quite evident 

that something has changed.  

john h

mkIII

John Hauck

Joined: 09 Jan 2006
Posts: 4639
Location: Titus, Alabama (hauck's holler)

Posted: Mon Jul 21, 2008 9:38 am Post subject: Drooping FireFly Flaperons

> As for the W&B, The original builder of my FS II added 10lbs of ballast 

to the nose a few hours after the first flight. It was kind of tail heavy 

without it mostly due to the use of the C box and clutch on the engine, 

which adds 10lbs over the B box at an arm pretty well behind the CG.

 >

 	  Quote: 	
		   LS


	




Lucien:



There are other ways to trim a Kolb rather than add additional weight.



john h

mkIII

_________________
John Hauck
MKIII/912ULS
hauck's holler
Titus, Alabama

Ricochet

Joined: 29 May 2008
Posts: 36
Location: Fresno, CA

Posted: Mon Jul 21, 2008 10:08 am Post subject: Drooping FireFly Flaperons

John,



Wish I had known what they were when I rebuilt my Firestar.  On my  

first flight I had to push the stick as far forward with my  

fingertips to get it to land.  A weight and balance indicated I  

needed 50 lbs or so in the nose.  Called the factory and was told  

their pilot normally carried similar weight in theirs.  A friend  

later built a FS II and found after a w&b he needed a bunch of weight  

in the nose.  So what is the secret, change of incidence in the  

horizontal stab?



Ricochet

 	  Quote: 	
		  



 Lucien:



 There are other ways to trim a Kolb rather than add additional weight.



 john h

 mkIII

John Hauck

Joined: 09 Jan 2006
Posts: 4639
Location: Titus, Alabama (hauck's holler)

Posted: Mon Jul 21, 2008 10:43 am Post subject: Drooping FireFly Flaperons

 	  Quote: 	
		    On my

 first flight I had to push the stick as far forward with my  fingertips to 

 get it to land.  A weight and balance indicated I  needed 50 lbs or so in 

 the nose.  Called the factory and was told  their pilot normally carried 

 similar weight in theirs.  A friend  later built a FS II and found after a 

 w&b he needed a bunch of weight  in the nose.  So what is the secret, 

 change of incidence in the  horizontal stab?



 Ricochet


	




Jerry J/Gang:



If it were my Kolb, I'd probably droop the ailerons a tad at a time until I 

got it in pitch trim.



I can also adjust pitch trim with leading edge of the elevator, but should 

not have to do this if the aircraft was built  was built to specs.



An elevator trim tab can also be used to tame pitch trim.



Quite possibly, your FS may have changed its characteristics during the 

rebuild.



The last thing I would want to do is carry additional weight.



I, personally, would never carry 50 lbs of lead in the nose of my Kolb to 

trim it in pitch or make the numbers on the weight and balance work out.



Who at the "factory" gave you info reference additional weight in the nose?



Adjusting ailerons up or down is the simplest and easiest way to adjust 

pitch trim.  Well.............you could lean forward to land.  



To qualify my post, this is what I would do to trim one of my Kolbs.  I am 

not recommending anyone else do this to trim their Kolb.



john h

mkIII

_________________
John Hauck
MKIII/912ULS
hauck's holler
Titus, Alabama

slyck(at)frontiernet.net
Guest

Posted: Mon Jul 21, 2008 10:54 am Post subject: Drooping FireFly Flaperons

A fatter pilot.

Change tailplane incidence

move seat forward

all of the above

In my MkIII, when I did the initial W&B it looked a little tail heavy  

too so I concealed

two 15 lb bricks of lead in the nose cone.  I created a little  

compartment with a door

to make it reversible.   Flew ok, so I took one out.  Still ok, so  

out came the second brick.

No difference except I'm not toting around 30 lbs of dead weight.

The MkIII (at least mine) has a remarkably neutral stick pressure.   

Even one notch

of flaps requires only a small stick back pressure.

It is a very docile and comfortable airplane, perfectly suited for  

their elderly owners.  

Lighter aircraft are of course more sensitive to weights and trim.

BB, stuck inside with heavy rain all about.

do not archive

On 21, Jul 2008, at 2:06 PM, Jerry Jones wrote:

 	  Quote: 	

 John,

 Wish I had known what they were when I rebuilt my Firestar.  On my  

 first flight I had to push the stick as far forward with my  

 fingertips to get it to land.  A weight and balance indicated I  

 needed 50 lbs or so in the nose.  Called the factory and was told  

 their pilot normally carried similar weight in theirs.  A friend  

 later built a FS II and found after a w&b he needed a bunch of  

 weight in the nose.  So what is the secret, change of incidence in  

 the horizontal stab?

 Ricochet

> Lucien:

>

> There are other ways to trim a Kolb rather than add additional  

> weight.

>

> john h

> mkIII

lucien

Joined: 03 Jun 2007
Posts: 721
Location: santa fe, NM

Posted: Mon Jul 21, 2008 1:00 pm Post subject: Re: Drooping FireFly Flaperons

 	  John Hauck wrote: 	
		  



Lucien:



There are other ways to trim a Kolb rather than add additional weight.



john h

mkIII 	




I remember going through the logbooks on this as he documented various of the things he did during the phase I in trimming the plane out. We also talked about it when I went to look at the plane.



He did make some changes to the "droop" of the ailerons, but didn't add any trim tabs to the elevator or make any incidence changes to the stab. 



The only reason I could see that he added ballast (10lbs) was because the original W&B came in right at the aft limit in his most-aft scenario (can't remember exactly what that was). The ballast moved that forward about an inch.



IMO, it flew slightly nose-heavy even with me in it (I'm about 195, he was about 220), without any stick pressure it wanted to cruise at 70mph or even a little more and was difficult to 3-point even when trying.



So I think it was probably ok without it, tho I didn't try to take it out to see.



Still loved the way it flew, it didn't do anything goofy and the engine loafed most of the time....



LS

_________________
LS
Titan II SS

Ricochet

Joined: 29 May 2008
Posts: 36
Location: Fresno, CA

Posted: Mon Jul 21, 2008 1:23 pm Post subject: Drooping FireFly Flaperons

Thanks guys for ideas on how to avoid carrying around extra freight  

in the nose.  And, John, don't recall now who at the factory I spoke  

with about their carrying extra weight in the nose.  It was six to  

nine years ago, but I'd probably still forget if it was yesterday.   

Seemed strange to me they said they carried extra weight, given how  

the Fly-in Kolb lands and takes off in a shorter distance than  

anything I've seen.  Next time I run into the problem of having to  

push the stick forward with my finger tips to fly level and land,  

I'll consider these other ideas.  Yea, extra weight normally isn't a  

good thing.



Jerry

 	  Quote:

John Hauck

Joined: 09 Jan 2006
Posts: 4639
Location: Titus, Alabama (hauck's holler)

Posted: Mon Jul 21, 2008 1:48 pm Post subject: Drooping FireFly Flaperons

 	  Quote: 	
		   Seemed strange to me they said they carried extra weight, given how  

 the Fly-in Kolb lands and takes off in a shorter distance than  

 anything I've seen.  Next time I run into the problem of having to  

 push the stick forward with my finger tips to fly level and land,  

 I'll consider these other ideas.  Yea, extra weight normally isn't a  

 good thing.

 

 Jerry

 
	




Jerry/Gang:



None of the factory aircraft carry ballast weights.



How did you correct the improper trim on your Kolb?



john h

mkIII

_________________
John Hauck
MKIII/912ULS
hauck's holler
Titus, Alabama

gaman(at)att.net
Guest

Posted: Mon Jul 21, 2008 2:37 pm Post subject: Drooping FireFly Flaperons

John,

Am I missing something or do you not use conventional W&B calculations on your MK-3?

                     G.Aman MK-3C



---

Ricochet

Joined: 29 May 2008
Posts: 36
Location: Fresno, CA

Posted: Mon Jul 21, 2008 2:39 pm Post subject: Drooping FireFly Flaperons

John,



I strapped 35 lb of lead in the nose of my 503 DCDI Firestar, which  

always seemed like a waste.  Now I see it might have been.  Two of my  

Firestar flying friends have nothing, which made me wonder about the  

weight I carried.  After this discussion I can now sleep peacefully  

without worrying about them or wondering what I would do if I built/ 

bought another Kolb---miss flying at a 45 degrees in sidewinds and  

lots of other special characteristics of my Kolb.



Jerry

 	  Quote: 	
		  

 Jerry/Gang:



 None of the factory aircraft carry ballast weights.



 How did you correct the improper trim on your Kolb?



 john h

jbhart(at)onlyinternet.ne
Guest

Posted: Mon Jul 21, 2008 5:02 pm Post subject: Drooping FireFly Flaperons

At 07:39 PM 7/20/08 -0500, you wrote:

 	  Quote: 	

 > Drooped

>

> Jack B. Hart FF004

Hi Jack H:

That is what I thought.

Drooping flaperons or flaps pushes the nose down, requiring more aft 

pressure to remain level.

Reflexing them will pull the nose up, requiring less aft pressure, or if 

reflexed enough, you will then have to apply forward pressure on the stick 

to remain level.

This is the opposite effect you got?????

Wonder why your aircraft responded in an opposite manner?

John H.,

I don't believe it is responding in the opposite manner. What I am trying to 

do is to maintain constant altitude flight, but at a lower speed.  As I said 

my FireFly is trimmed for level flight at 5,500 rpm with 50 mphi with the 

stick in the neutral position.  If I slow the engine to 5,000 rpm I get 40 

mphi and I must increase stick back pressure to raise the elevator five 

degrees to maintain altitude. This puts the FireFly in a nose high position. 

 Then I lower the flaperons one degree and the nose drops a little.  If I 

maintain the stick/elevator position at five degrees, the FireFly starts to 

climb.  To keep from climbing I have to let the stick go forward which drops 

the nose a little more.  And so I can maintain constant altitude at 40 mphi 

with less stick back pressure with one degree of flaperon.

I believe you may be confusing level attitude with constant altitude.

Jack B Hart FF004

Winchester, IN

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