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Flaperons, Trim Settings, & CG

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kerrjohna(at)comcast.net
Guest

Posted: Tue Sep 23, 2008 4:06 am Post subject: Flaperons, Trim Settings, & CG

Several comments: apart from the effect on pitch with flaps, you probably don't want to correct a balance/weight issue with aerodynamics.



The limits could be brought in line with a relocation of the battery (heavier battery) in the tail. Try flying after calculating w/b the effect of a secured 10# bag of shot located on the tail spring bolt. 



Gap seal will help elevator authority. Plain(plane) sticky shelf paper from Smith's Marketplace works great though I can not attest to its longevity.  Mine has been on for 12 years and is still flexible.



Where does "drastic" begin when applying flaps.  The classic iv as with your earlier iii requires increasing amounts of back stick as flap is added, and is fairly linear.  In stalls can you sense whether it is stabilizer popping up or the wings losing lift?

 -------------- Original message ----------------------

From: "darinh" <gerns25(at)netscape.net>

 	  Quote: 	
		   

 

 Here is the deal.  My Series 7, when flying solo with half tanks has a CG of 

 about 10" (forward CG limit is 9" and aft is 16").  This is a bit on the nose 

 heavy side...this is due to my engine and prop choice which together add about 

 30 lbs over the standard 912s and Warp Drive prop.

 

 I really would like to use the flaperons during landing to lower my stall speed 

 but when I deploy them the nose pitches forward quite a bit.  So much that I can 

 only flare to about a level attitude and this is with only the first notch of 

 flaperons.  I know you can put the trim assist on that reduces the back pressure 

 on the stick but this doesn't help with the amount of flare available.  Here is 

 the question:  At what CG will the plane NOT experience a drastic pitch forward 

 when flaperons are deployed (12", 14", 15", ect.)?  Has anyone done this test?  

 Any comments on this? Or techniques that work for you?

 

 I have heard that sealing the gap on the elevator will give better elevator 

 authority as will adding VGs to the bottom side of the stab.  I have not done 

 this yet but will definitely seal the gaps....don't know about the VGs.

 

 --------

 Darin Hawkes

 Series 7 (Phase 1 - Flight Testing)

 914 Turbo

 Kaysville, Utah

 

 

 

 

 Read this topic online here:

 

 http://forums.matronics.com/viewtopic.php?p 5590#205590

Guy Buchanan

Joined: 16 Jul 2006
Posts: 1204
Location: Ramona, CA

Posted: Tue Sep 23, 2008 8:55 am Post subject: Flaperons, Trim Settings, & CG

At 04:37 PM 9/22/2008, you wrote:

 	  Quote: 	
		  At what CG will the plane NOT experience a drastic pitch forward 

when flaperons are deployed (12", 14", 15", ect.)?  Has anyone done 

this test?  Any comments on this? Or techniques that work for you?


	


The flaperons will always cause a pitch change, because they operate 

as a stabilator, albeit one on a very short fuselage! Do you not have 

an elevator trim system? If not, I'd contact Lowell and get one 

installed ASAP, as it will make your flying experience much better.



 	  Quote: 	
		  I have heard that sealing the gap on the elevator will give better 

elevator authority as will adding VGs to the bottom side of the 

stab.  I have not done this yet but will definitely seal the 

gaps....don't know about the VGs.


	


On a IV gap sealing makes a substantial difference in elevator 

authority in the flare.

Guy Buchanan

San Diego, CA

K-IV 1200 / 582-C / Warp / 100% done, thanks mostly to Bob Ducar.

_________________
Guy Buchanan
Deceased K-IV 1200
A glider pilot too.

darinh

Joined: 20 Apr 2006
Posts: 327
Location: Utah

Posted: Tue Sep 23, 2008 10:53 am Post subject: Re: Flaperons, Trim Settings, & CG

John,



I don't like the idea of the battery in the tail but I do think a adjustable weight system would be the ticket.  That way, when I do load the airplane up I can take the weight out and still be within the CG range.



Guy,



Yes, I have the trim system with the dual tabs on the elevators and can trim the airplane for level fly or steady descent rate with flaps but it is the amount of elevator authority that is the problem when flaring.  Without flaps, it is fine, with flaps there is not enough to get the tail down so wheel landings are all that are possible...wheel landings are fine but I prefer the full stall landing most of the time.



My question was more along the lines of how much the down pitch changes in respect to CG location.

_________________
Darin Hawkes
Series 7
914 Turbo
Kaysville, Utah

kerrjohna(at)comcast.net
Guest

Posted: Tue Sep 23, 2008 11:01 am Post subject: Flaperons, Trim Settings, & CG

Sounds like you are a prime candidate for gap seals.  I can help you with that.

  

 John

  

 [quote]-------------- Original message -------------- 

From: "darinh" <gerns25(at)netscape.net> 



[quote] --> Kitfox-List message posted by: "darinh" 

 

 John, 

 

 I don't like the idea of the battery in the tail but I do think a adjustable 

 weight system would be the ticket. That way, when I do load the airplane up I 

 can take the weight out and still be within the CG range. 

 

 Guy, 

 

 Yes, I have the trim system with the dual tabs on the elevators and can trim the 

 airplane for level fly or steady descent rate with flaps but it is the amount of 

 elevator authority that is the problem when flaring. Without flaps, it is fine, 

 with flaps there is not enough to get the tail down so wheel landings are all 

 that are possible...wheel landings are fine but I prefe  r the   e Web   [quote][b]

matronics(at)bob.brennan.
Guest

Posted: Tue Sep 23, 2008 11:17 am Post subject: Flaperons, Trim Settings, & CG

Can someone here please explain "gap seals"? I have some  fabric tape on the gap between the vertical stabilizer and the rudder and think  I saw a note somewhere about it giving more yaw authority, which the  Model II famously lacks. Does the same thing apply to the  horizontal?

  

  Bob Brennan - N717GB

 1991 UK Model 2 ELSA  Kitfox

 Rotax 582 with 3 blade  prop

 Wrightsville Pa 

  



   From: owner-kitfox-list-server(at)matronics.com  [mailto:owner-kitfox-list-server(at)matronics.com] On Behalf Of  kerrjohna(at)comcast.net

Sent: 23 September 2008 2:59  pm

To: kitfox-list(at)matronics.com

Subject: Re: Kitfox-List:  Re: Flaperons, Trim Settings, & CG

 

 Sounds like you are a prime candidate for gap seals.  I can help you  with that.

  

 John

  

 [quote]--------------    Original message -------------- 

From: "darinh"    <gerns25(at)netscape.net> 



 	  Quote: 	
		   --> Kitfox-List message posted    by: "darinh" 

 

 John, 

 

 I    don't like the idea of the battery in the tail but I do think a adjustable    

 weight system would be the ticket. That way, when I do load the    airplane up I 

 can take the weight out and still be within the CG    range. 

 

 Guy, 

 

 Yes, I have the trim system    with the dual tabs on the elevators and can trim the 

 airplane for    level fly or steady descent rate with flaps but it is the amount of 

    elevator authority that is the problem when flaring. Without flaps, it is    fine, 

 with flaps there is not enough to get the tail down so wheel    landings are all 

 that are possible...wheel landings are fine but I    prefe r the e Web  	  Quote: 	
		  


	


href="http://www.matronics.com/Navigator?Kitfox-List">http://www.matronhref="http://forums.matronics.com">http://forums.matronics.com

href="http://www.matronics.com/contribution">http://www.matronics.com/c

	
[b]

darinh

Joined: 20 Apr 2006
Posts: 327
Location: Utah

Posted: Tue Sep 23, 2008 11:54 am Post subject: Re: Flaperons, Trim Settings, & CG

John,



Thanks for the offer but I put them on last night.  I used the 3M polyurethane film they put on the front of cars (know as "Clear bra") and it was slick.  It is virtually transparent and looks great...was a bit of a pain to stick the two pieces together without bubbles but a little Windex and a squeegee helped.  I was going to fly it this morning to see the effect but staying up until 1:30 applying it put an end to that thinking.  I will test it out tomorrow.



Bob, 



Sealing the gap on the horizontal will give increased performance just like on the vertical...at least theoretically.

_________________
Darin Hawkes
Series 7
914 Turbo
Kaysville, Utah

kerrjohna(at)comcast.net
Guest

Posted: Tue Sep 23, 2008 12:35 pm Post subject: Flaperons, Trim Settings, & CG

good, let us know the results.

  

 John

  

 [quote]-------------- Original message -------------- 

From: "darinh" <gerns25(at)netscape.net> 



[quote] --> Kitfox-List message posted by: "darinh" 

 

 John, 

 

 Thanks for the offer but I put them on last night. I used the 3M polyurethane 

 film they put on the front of cars (know as "Clear bra") and it was slick. It 

 is virtually transparent and looks great...was a bit of a pain to stick the two 

 pieces together without bubbles but a little Windex and a squeegee helped. I 

 was going to fly it this morning to see the effect but staying up until 1:30 

 applying it put an end to that thinking. I will test it out tomorrow. 

 

 Bob, 

 

 Sealing the gap on the horizontal will give increased performance just like on 

 the vertical...at least theoretically. 

 <  BR>&gt  

&g   	  Quote: 	
		  [b]

lcfitt(at)sbcglobal.net
Guest

Posted: Tue Sep 23, 2008 12:52 pm Post subject: Flaperons, Trim Settings, & CG

Darin,



A local guy - since taken by cancer - built a Series V with the IO240, I 

believe.  His solution to the heavy firewall forward was to mount a small 

metal toolbox on the aft baggage compartment  floor with some lead shot in 

it.  It was part of the equipment list, but was exchanged for baggage when 

going on long trips.  I don't know what he did if he wanted to do come 

exporing once there, but it is one idea that has been used.



Lowell

---

akflyer

Joined: 07 May 2007
Posts: 574
Location: Soldotna AK

Posted: Tue Sep 23, 2008 3:52 pm Post subject: Re: Flaperons, Trim Settings, & CG

 	  darinh wrote: 	
		  John,



Thanks for the offer but I put them on last night.  I used the 3M polyurethane film they put on the front of cars (know as "Clear bra") and it was slick.  It is virtually transparent and looks great...was a bit of a pain to stick the two pieces together without bubbles but a little Windex and a squeegee helped.  I was going to fly it this morning to see the effect but staying up until 1:30 applying it put an end to that thinking.  I will test it out tomorrow.



Bob, 



Sealing the gap on the horizontal will give increased performance just like on the vertical...at least theoretically. 	


When we put my brothers II on floats I was not able to get the touch down speed under 50 until I sealed the gap on the elevator with what I had on hand... Duct tape.  With gap seals I never run out of elevator even uhhuh at "gross" plus.  I can drag it in at 35-38.

_________________
DO NOT ARCHIVE
Leonard Perry aka SNAKE
Soldotna AK
Avid "C" / Mk IV
582 (147 hrs and counting on the rebuild)
IVO IFA
Full Lotus 1450
#1 snake oil salesman since 1-22-2009

I would rather die trying to live, than to live trying not to die....

Float Flyr

Joined: 19 Jul 2006
Posts: 2704
Location: Campbellton, Newfoundland

Posted: Wed Sep 24, 2008 7:18 am Post subject: Flaperons, Trim Settings, & CG

He could have put the shot in plastic bags inside the box... That way if he

wanted to move the weight forward he could stow it in a pod or under/on a

seat.  Lots of opportunities there as long as the bag was secured.  



The 206 JetRanger sometimes will carry a lead strap in the luggage

compartment.  That lead strap is attached to the fornt of the right skid if

the pilot is less than a specific weight.  If the same pilot is carrying

passengers or a load the ballast weight can sit in the cargo compartment.  I

think they typically weighed 20 lb.



Noel



--

_________________
Noel Loveys
Kitfox III-A
Aerocet 1100 Floats

n85ae

Joined: 14 Mar 2007
Posts: 403

Posted: Wed Sep 24, 2008 11:07 am Post subject: Re: Flaperons, Trim Settings, & CG

I welded up a ballast box which is attached to the aiframe tubing back

by the trim actuator, and I keep 10 lb.s of lead in it, along with a 

Odyssey PC-680 battery. I have an IO-240B. This get's my balance 

where the plane handles very nicely and I never have problems with 

elevator authority.



Jeff

Guy Buchanan

Joined: 16 Jul 2006
Posts: 1204
Location: Ramona, CA

Posted: Wed Sep 24, 2008 11:39 am Post subject: Flaperons, Trim Settings, & CG

At 12:17 PM 9/23/2008, you wrote:

  	  Quote: 	
		  Can someone here please explain "gap seals"? I have some fabric tape on the gap between the vertical stabilizer and the rudder and think I saw a note somewhere about it giving more yaw authority, which the Model II famously lacks. Does the same thing apply to the horizontal? 	


 Gap seal - anything that prevents flow from the high to low pressure side of the airfoil. Some use close tolerance fiberglass structures; others, like me, use clear tape from the top of one surface to the bottom of the other. It looks fine if done carefully and replaced occasionally.  It can be done on the vertical and horizontal stabilizer. When I did mine I went from full flaps giving full up elevator at touchdown on a three-point to full flaps giving probably 75% up elevator at touchdown- a significant improvement.



 

 Guy Buchanan

 San Diego, CA

 K-IV 1200 / 582-C / Warp / 100% done, thanks mostly to Bob Ducar.    [quote][b]

_________________
Guy Buchanan
Deceased K-IV 1200
A glider pilot too.

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