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bakerocb

Joined: 15 Jan 2006
Posts: 727
Location: FAIRFAX VA

Posted: Tue Feb 22, 2011 7:08 am Post subject: Landing the KIS TR-1

2/22/2011



Hello Alfred, You wrote: "All landings (about 13) thus far have been dead 

stick glide curves onto short final."



Some questions if I may:



1) What indicated airspeed do you use during this glide?



2) What flap configuration are you using during this glide and touch down?



3) Do you use any power above idle prior to touch down?



4) Any further comments on landing technique?



Thanks,



OC



==================================================

---

BlueSkyFlier

Joined: 27 Jan 2011
Posts: 74
Location: UK

Posted: Tue Feb 22, 2011 7:30 pm Post subject: Re: Landing the KIS TR-1

Hi OC,



Answered as per my direct mail to you. As concluded, best for everyone to use the technique they are most trained in.



IMPORTANT: The KIS is not a suitable craft in which to attempt learning the technique I described.



Best to pay for 15+ hrs of circuits in a 3-axis microlight to bed down the technique before attempting it on the KIS.



Each to his own and none the worse for it. That's how we make the world go round ;o)



Regards,

            Alfred

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BlueSkyFlier

Joined: 27 Jan 2011
Posts: 74
Location: UK

Posted: Tue Apr 05, 2011 2:28 pm Post subject: Re: Landing the KIS TR-1

Since before buying the KIS TR-1 late last year I have been researching the possible reasons for the nose dropping tendency which the TR-1 is sometimes alleged to display on occasion.  During this exercise I learned quite a bit about laminar flow wings and ground effect, the sum of which led to me to conclude in brief that:

1)	NACA six digit laminar flow wing (even with straightened rear profile) definitely prefers to be operated within its design range – which for the KIS is nominally where  0 ≤ CL ≤ 0.4

2)	Angles of attack which pushes CL > 0.8 for the 63(2)A215  profile profile rapidly increase the negative moment (i.e. the forward pitching moment) [where “A” in the profile code accounts for the flat surfaced flap and ailerons at the rear of the wing]. 

3)	The flat surfaces on the flaps and ailerons could apparently be the reason (inter alia) why the TR-1 tends to mush gently in the stall instead of popping down the nose.

4)	 When entering ground effect whilst maintaining a fairly conservative angle of attack, the vlaue of CL  will increase automatically by between 5% to 8% [refer attached diagram]. Viewed on its own this would seem to be a beneficial effect. However, at the same time, the critical angle of attack (i.e. the stall angle where boundary layer separation occurs) and associated CLmax decrease due to changes in pressure distribution. It follows that, if ground effect is entered with an angle of attack which is too close to CLmax , the combination of resultant increase in CL , decrease in CLmax and increasing negative moment may tip the balance over the edge and conspire to upset the stable state of affairs.

5)	Furthermore, the changed angle of airflow across the low tail section could also reduce the elevator authority required to offset the increased negative moment and/or counteract the imbalance which may arise.



Over the weekend I finally came across two references below which seem to pull all these fragments together into a whole that makes sense. 

(i)	“Synthesis of subsonic airplane design” by Egbert Torenbeek, page 552 in particular.

(ii)	Analysis of the aerodynamic chracteristics of devices for increasing wing lift – Part III – Influence of ground proximity on the aerodynamic characteristics of the flaps; by Rafael Garncarek – translated from the original for NACA’s library.

(Small excerpts from the relevant pages of these two reference are attached with due acknowledgement to the respective authors.)



So what does this all mean? To me at least, it indicates that the TR-1 (which is but one example of such laminar flow low wing aircraft) would provide a good margin of security during landing if the main gear is touched down at circa 55 to 65 kts with a fairly flat aircraft attitude and with only one stage of flaps - providing runway and other factors allow. Attempts to hold off at high angle of attack with full flaps close to the ground may well invite the unwelcome effects mentioned earlier, all of which can be avoided by getting the gear down before bleeding off the residual speed by carefully keeping the nose up while she runs out. Setting RPM in descent/glide to the “zero prop drag” value will also help. Such RPM setting can simply be calculated from the propeller pitch and intended touchdown speed and does not need to be very precise at all. Somewhere between 1300 and 1450 would work well for most propellers and of course this has to be reduced gently to idle as main gear settles down. 



NOTE: I know that the matter of appropriate landing technique may be an emotive subject to some readers. So let me make it clear that I am merely sharing this information and what little understanding was (maybe erroneously so) gleaned from it for general interest. This does not constitute a recommendation in any way shape or form and readers are urged to draw their own conclusions from the original material and relevant further references therein if so inclined.  



Happy landings,

                               Alfred

Aerodynamic effects in ground effect.jpg

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Ground Effect on Lift Coefficient.jpg

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BlueSkyFlier

Joined: 27 Jan 2011
Posts: 74
Location: UK

Posted: Wed Apr 06, 2011 1:27 am Post subject: Re: Landing the KIS TR-1

Of particular interest in the diagram which illustrates changes in lift coefficient in ground effect [attached to previous message above] is the tendency for lift to drop away when less than 20% of wingspan away from the ground if the CL > 2.



With full flaps the TR-1 wing can apparently achieve CL > 2 if the angle of attack is steep enough. In fact, when holding off with full flaps at high angle of attack in close proximity to the ground it is likely that this unexpected drop-off effect could be encountered - not to mention the contribution of adverse tail plane effects.



It therefore seems important to keep the angle of attack fairly conservative. This can be done by flying the main gear into touch with a fairly low angle of attack and comfortable speed (probably > 60 kts) . Once the gear is down the nose can be pulled up gently to generate maximum drag (the TR-1 will fortunately not easily lift off again without power). 



(The equation from which the lift coefficient chart attached above was created is attached below for interest. The TR-1 aspect ratio being less than 7 will tend to exacerbate the unwanted effects.)

-- ** --

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gbrighton(at)skymesh.com.
Guest

Posted: Wed Apr 06, 2011 2:49 pm Post subject: Landing the KIS TR-1

Alfred ,

                Thx for sharing ur amazing and comprehensive study of the 

Laminar Flow lift characteristics that CHANGE at landing as applied to our 

TR-1 ..

                My head like others is still er..'spinning' ...but ..ur 

preposition as i understand it ....which is backed up ur substantial 

research is ....that its the lift changes on our Laminar Wing at touch down 

that causes the nose to drop and be hard/impossible to hold up after mains 

touch down ... ( the wing lift/moment changes causes the Tail to loose 

authority to counter the drop) ..



                 However with careful Speed and Flap selection the 'Nose 

Drop' effect can be minimized ..



Great work ...Do i have this rite or .... !?



Graham

TR1 #80

BlueSkyFlier

Joined: 27 Jan 2011
Posts: 74
Location: UK

Posted: Wed Apr 06, 2011 3:48 pm Post subject: Re: Landing the KIS TR-1

Hi Graham,



Unfortunately it is never just one thing. Far too much going on at the same time to be that simple )



The wing effects, flaps effects and changed airflow on the tail section all play their part. The upwash effects on tail plane could vary dramatically with speed, flap setting, angle of attack, and height above ground.



Most people (myself included) were told in training that ground effect always increase lift. As the references illustrate that statement should be qualified with the provision that the angle of attack needs to be small enough.



With low wing aircraft in particular, the proximity of the trailing edge of the flaps to the ground can work in one's favour if the lift coefficient is small enough, but could just as well have exactly the opposite effect if one is not careful with angle of attack.



The bottom line is that unless these adverse factors are avoided, any or all of them can contribute to the craft and/or nose gear coming down faster than one would want or expect.  Each pilot will naturally develop their own way of dealing with these effects, but understanding of the various parameters at play can only be beneficial.



Regards,

            Alfred

_________________
_________________________________________

mantafs(at)earthlink.net
Guest

Posted: Wed Apr 06, 2011 6:49 pm Post subject: Landing the KIS TR-1

I may be wrong but it seems to me that this is looking for a complex reason for a very simply issue.  As designed the main gear is too far aft.  I think most if not all of the problem is once the mains touch down they impart a huge nose down moment due to their placement too far aft of the CG.  I do not think anyone has had a real issue holding the nose up when flying even in low ground effect.  I think the issue is only after the mains contact.



I also very much suspect the diagram and equation.  I would really like to see the theory, math and experimental data behind it.  To me it looks like a suspect empirical equation that seem to be way too popular in some aircraft design textbooks and in many papers.  Not that empirical equations are not useful.  They are!  But you really need to be careful when applying them especially at one end or the other as in this case.  



But even if the equation is correct I very much doubt the KIS achieves much more than 1.8 Cl even in the flapped area so this should still not be an issue.



Again, I could be wrong.  And I am sorry if I am stepping on any toes but just wanted to express a counterpoint.



Mark

--

lgdavid(at)roadrunner.com
Guest

Posted: Wed Apr 06, 2011 9:02 pm Post subject: Landing the KIS TR-1

Several years ago, Julian Bone did a rather complete study of the     airflow effect of the KIS wing fairing.  It appears from a book by     Stinton, page171, that if the wing fairing needs         about an 8 inch radius instead of the ~3 in radius it has.  With         the ~8 inch radius, the airflow over the tail will not be         turbulent and the nose will not drop unexpectedly.  Julian         modified his plane accordingly and it solved the problem.  I         found the Stinton book very interesting.  (I think the title was         "The design of an Airplane."  I loaned my copy to another         builder so have to trust my memory on the title so I may not be         right.).  Hope this sheds some more light on the     issue.  Larry

     

     On 4/6/2011 4:48 PM, BlueSkyFlier wrote:     [quote]        	  Quote: 	
		  --> KIS-List message posted by: "BlueSkyFlier" <bleuskyfly(at)teledynamix.com> (bleuskyfly(at)teledynamix.com)



Hi Graham,



Unfortunately it is never just one thing. Far too much going on at the same time to be that simple )



The wing effects, flaps effects and changed airflow on the tail section all play their part. The upwash effects on tail plane could vary dramatically with speed, flap setting, angle of attack, and height above ground.



Most people (myself included) were told in training that ground effect always increase lift. As the references illustrate that statement should be qualified with the provision that the angle of attack needs to be small enough.



With low wing aircraft in particular, the proximity of the trailing edge of the flaps to the ground can work in one's favour if the lift coefficient is small enough, but could just as well have exactly the opposite effect if one is not careful with angle of attack.



The bottom line is that unless these adverse factors are avoided, any or all of them can contribute to the craft and/or nose gear coming down faster than one would want or expect.  Each pilot will naturally develop their own way of dealing with these effects, but understanding of the various parameters at play can only be beneficial.



Regards,

            Alfred



--------

_________________________________________





Read this topic online here:



http://forums.matronics.com/viewtopic.php?p=336321#336321



	
     [b]

mantafs(at)earthlink.net
Guest

Posted: Thu Apr 07, 2011 5:34 am Post subject: Landing the KIS TR-1

I am a very big fan of Stinton's book "The Design of the Aeroplane".  Lots of useful information. It does have a fair number of empirical equations but he tends to use them with care, a grain of salt and with data.  This is the first book I look at when I have questions.



Julian Bone did some great work on the airflow at the wing root of the KIS.  I agree that a much larger radius fairing will reduce drag, reduce turbulence, reduce the adverse pressure gradient especially at high AOA and help delay wing root stall.  Yes, delaying stall will decrease minimum flying speed and that is good.  But wing root stall (or for that matter any wing stall) will drop the nose!  Nothing to do with turbulent airflow over the tail.  Airfoils work great in turbulent air.  In fact they tend to work better in some ways with a higher maximum Cl.  There is of course wing down wash over the tail and this will be reduced when the wing stalls and this will reduce tail down force.  But this is a lower order effect then the moment due to the reduced wing lift due to wing stall and more aft stick can make up for this, not that you would want to if the wing is in stall. 



Was Julian Bone's aircraft conventional gear?  What problem did he really solve?  I know he decreased the minimum airspeed and this is good.  He maybe reduced minimum airspeed such that now the tail can not generate the needed down force (at some forward CG locations) to make the AOA such that the wing will stall.  This may be good and was done with some aircraft in the past like the AirCoupe.  But maybe now the wings tips will stall first and this is bad.  



Mark



--

BlueSkyFlier

Joined: 27 Jan 2011
Posts: 74
Location: UK

Posted: Thu Apr 07, 2011 6:18 am Post subject: Re: Landing the KIS TR-1

Chuckle ... don't worry guys. Long toes are not my strong suit ) This is developing into exactly the kind of conversation I was hoping for. 



Fully agreed with Mark that, if the resultant vertical momentum is too high at touchdown, the weight of the engine will take the upper hand in forcing the nose down.



I was merely looking for potential causal factors of such undesirable end result which could catch one unawares even when apparently doing nothing overtly wrong. In that sense the equation did point out that - as rear end of flaps get closer to the ground - flow velocity becomes restricted and probability of flow reversal increases; all of which reduces lift of the inner wing area. Empirical or not, it seems to make intuitive sense and I shall at least keep that effect in mind when I have full flaps deployed in approach. Also good to hear from Mark that TR-1 will not easily get into the CL > 2 region.



Unfavorable air flow on the tail section is probably also strongly influenced by angle of attack. Julian had a tail dragger and was therefore more likely to end up with the tail lower than we would normally do.



Must admit that I have not personally experienced nose dropping - perhaps because I don't hold off, but instead fly the gear into touch with conservative angle of attack as I was instructed to do at hot and high fields. I seems to work everywhere else too.



Happy landings )

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ftyoder(at)yoderbuilt.com
Guest

Posted: Thu Apr 07, 2011 6:53 am Post subject: Landing the KIS TR-1

Julian's was a tail dragger.

---

mantafs(at)earthlink.net
Guest

Posted: Thu Apr 07, 2011 2:12 pm Post subject: Landing the KIS TR-1

 	  Quote: 	
		  Fully agreed with Mark that, if the resultant vertical momentum is too high at touchdown, the weight of the engine will take the upper hand in forcing the nose down.


	


Actually even if there is no (or almost no) vertical momentum on touchdown the nose can still slam down due to the upward force that was being generated by the wing now being generated by the main gear farther aft.



 	  Quote: 	
		  

I was merely looking for potential causal factors of such undesirable end result which could catch one unawares even when apparently doing nothing overtly wrong. In that sense the equation did point out that - as rear end of flaps get closer to the ground - flow velocity becomes restricted and probability of flow reversal increases; all of which reduces lift of the inner wing area. Empirical or not, it seems to make intuitive sense and I shall at least keep that effect in mind when I have full flaps deployed in approach. Also good to hear from Mark that TR-1 will not easily get into the CL > 2 region.


	


I agree with looking for any potential causal factors.  I also agree that with big flaps near the ground there could be flow restriction and maybe reversal.  But I am not so sure this will produce less lift.  Not that I am at all a fan of wings in ground effect craft but they do work and tend to have very low aspect ratios and very low trailing edge ground clearance.  Most do not have flaps but have lots of camber.



 	  Quote: 	
		  Must admit that I have not personally experienced nose dropping - perhaps because I don't hold off, but instead fly the gear into touch with conservative angle of attack as I was instructed to do at hot and high fields. I seems to work everywhere else too.




	


Do you know if your main gear are at the stock location or at some other location?



Mark

BlueSkyFlier

Joined: 27 Jan 2011
Posts: 74
Location: UK

Posted: Thu Apr 07, 2011 4:01 pm Post subject: Re: Landing the KIS TR-1

Mark,



I'm not sure what the actual height of CoG is for the TR-1, but I know that my wheels are located about 10 inches behind the nominal location of my CoG.



Attached herewith a table in which I explore the aircraft angle (away from horizontal) required at touchdown in order to bring the wheels underneath the centre of gravity. 



Assuming that CoG is about 36 inches above and 10 inches behind the wheels, it seems that one would need to have the aircraft at a 15.5 degree angle to get the wheels underneath the CoG.



Does anyone have nominal figures for height of CoG and/or aircraft angle at landing?

Aircraft angle at touchdown.jpg

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BlueSkyFlier

Joined: 27 Jan 2011
Posts: 74
Location: UK

Posted: Thu Apr 07, 2011 5:13 pm Post subject: Re: Landing the KIS TR-1

Earlier in this thread I referred to the tendency of NACA 6-digit wing profiles to prefer operation within their laminar flow design ranges. The KIS TR-1 uses a modified 6-digit profile which can be described as 63(2)A-215.



The 6-series was derived using an improved theoretical method that relied mathematics to derive the geometrical shape required to realise the desired pressure distribution. The goal of this approach was to design airfoils that maximized the region over which the airflow remains laminar. In so doing, the drag over a small range of lift coefficients can be substantially reduced. 



To illustrate that, herewith attached a diagram in which the characteristic drag "bucket" associated with laminar flow can be seen - in this case for the NACA 64(2)-415 profile. This is from p.238 of Torenbeek's "Synthesis of subsonic aircraft design".



As can be seen from the diagram the drag increases rapidly as the lift coefficient moves beyond the optimal range, which helps to slow down rapidly but also results in high sink rate at non-optimal angle of attack. However, these profiles do exhibit docile stall characteristics.



A modification of the standard 6-digit series is the A-series in which the curved contours of the trailing edge is replaced with straight contours which run from about 80% of chord backwards - as manifested by flat surfaces on the TR-1 flap and aileron. The TR-1 wing therefore nominally represents a 63(2)A215 profile.



Just one more reason to avoid high angles of attack during landing ...

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gbrighton(at)skymesh.com.
Guest

Posted: Thu Apr 07, 2011 7:39 pm Post subject: Landing the KIS TR-1

This is the only close Airfoil diagram i could find  .but its not the TR1 profile is it .. Anybody got the correct one  .?

  

 Graham

 TR1 #80

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sstearns2(at)yahoo.com
Guest

Posted: Thu Apr 07, 2011 8:25 pm Post subject: Landing the KIS TR-1

I'm pretty sure the pitch down issue on landing is due to the main wheels being a bit too far aft and the elevator being a bit too small.  It doesn't take much of an error in wheel placement to make a big difference in rotation speed and pitch down after touchdown.  

  

 When I was an engineer working on the proof of concept airplane for the Adam A500 we ended up with the main wheels a few inches aft of where they should have been (long story, not my fault!).  The airplane hit about 100 KIAS before it could be rotated for takeoff and there was no holding the nose off after landing.  Proteus is another good example.  The main wheels are well aft due to the design and the nose comes crashing down right after touchdown.  

  

 Scott

  

 



--- On Thu, 4/7/11, Mark Kettering <mantafs(at)earthlink.net> wrote:



  	  Quote: 	
		  

From: Mark Kettering <mantafs(at)earthlink.net>

Subject: Re: Re: Landing the KIS TR-1

To: kis-list(at)matronics.com

Date: Thursday, April 7, 2011, 3:10 PM



 --> KIS-List message posted by: Mark Kettering <mantafs(at)earthlink.net (mantafs(at)earthlink.net)>

 	  Quote: 	
		  Fully agreed with Mark that, if the resultant vertical momentum is too high at touchdown, the weight of the engine will take the upper hand in forcing the nose down.


	


Actually even if there is no (or almost no) vertical momentum on touchdown the nose can still slam down due to the upward force that was being generated by the wing now being generated by the main gear farther aft.



 	  Quote: 	
		  

I was merely looking for potential causal factors of such undesirable end result which could catch one unawares even when apparently doing nothing overtly wrong. In that sense the equation did point out that - as rear end of flaps get closer to the ground - flow velocity becomes restricted and probability of flow reversal  increases; all of which reduces lift of the inner wing area. Empirical or not, it seems to make intuitive sense and I shall at least keep that effect in mind when I have full flaps deployed in approach. Also good to hear from Mark that TR-1 will not easily get into the CL > 2 region.


	


I agree with looking for any potential causal factors.  I also agree that with big flaps near the ground there could be flow restriction and maybe reversal.  But I am not so sure this will produce less lift.  Not that I am at all a fan of wings in ground effect craft but they do work and tend to have very low aspect ratios and very low trailing edge ground clearance.  Most do not have flaps but have lots of camber.



 	  Quote: 	
		  Must admit that I have not personally experienced nose dropping - perhaps because I don't hold off, but instead fly the gear into touch with conservative angle of attack as I was instructed to do at hot and high fields. I  seems to work everywhere else too.




	


Do you know if your main gear are at the stock location or at some other location?



Mark

<-> 



	
 [quote][b]

BlueSkyFlier

Joined: 27 Jan 2011
Posts: 74
Location: UK

Posted: Fri Apr 08, 2011 1:42 am Post subject: Re: Landing the KIS TR-1

Attached below a short list which compares pertinent characteristics of some of the 63 series foils (obtained from the same website a where Graham got the profile attached earlier).



The 63(2)A-015 profile in the table is closest to the TR-1's 63(2)A-215 and differs from the others in higher L/D ratio and larger trailing edge angle due to the flat trailing edge profile.  The L/D ratio being highest even though the lift is less than the other airfoils indicates that the drag is quite low in comparison.



With Scott confirming effects of wheel placement, how about sharing figures for height of CoG? Since I have to work on my plane anyway I can just as well look at getting the main gear placement improved too.



Knowing that angle of incidence is 3 degrees and taking into account that stall angle is around 11.5 degrees (as from attached table) and assuming that full flaps decrease the angle of attack by about 2 or 3 degrees it seems that the aircraft angle at landing should be about 5.5 to 6.5 degrees maximum.



From the table attached to earlier message in this thread it then appears that the wheel location should be even less than 6 inches behind CoG - instead of the 10 inches it is now. If the main gear can be angled forward by about 10 degrees it should comes close to the sweet spot (depending on height of CoG).



I know that some builders have angled the gear forward. Does anyone have figures for that angle and or height of CoG?



Regards,

             Alfred

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bakerocb

Joined: 15 Jan 2006
Posts: 727
Location: FAIRFAX VA

Posted: Fri Apr 08, 2011 4:02 am Post subject: Landing the KIS TR-1

4/8/2011



Hello Fellow KIS TR-1 Pilots, Alfred wrote: "Just one more reason to avoid 

high angles of attack during landing ..."



I am in complete agreement with the technique of avoiding high angles of 

attack during the landing approach and flare while landing this airplane.



However I would like to clarify and emphasize that:



A) The danger / discomfort of having the nose abruptly drop while still 

airborne and close to the landing surface, and



B) The nuisance of not being able to hold the nose off after controlled main 

landing gear touchdown,



 are two very different situations.



While the airplane's design characteristics ( wing airfoil, wing to fuselage 

fairing, elevator effectiveness, main landing gear fore and aft placement, 

etc.) may or may not play some role in both A and B it is only A that will 

cause damage to airplane and injury to occupants.



The worst that is likely to come of B is greater brake pad surface wear as 

one can not make optimum use of an aerodynamic braking technique from the 

moment of main landing gear touchdown when landing on a surface that is long 

enough to make use of aerodynamic braking.



If one needs to make a short field landing the best way to get stopped as 

shortly as possible is to get all three gear on the ground as soon as 

possible and start wheel braking. Raising the flaps immediately after 

touchdown may also help wheel braking effectiveness.**



'OC' Baker Says: "The best investment we can make is the time and effort to 

gather and understand knowledge."



**PS: We could start another whole thread on the subject of practicing - 

making short field landings, but I am not keen to pursue that in detail. The 

KIS TR-1 design is not optimized for short field operations. While some 

owners / pilots have a need to and do operate from short fields it is not a 

good idea to routinely beat up this airplane practicing short field 

operations unless you have a real need for those operations.



=============================================================

From: "BlueSkyFlier" <bleuskyfly(at)teledynamix.com>

To: <kis-list(at)matronics.com>

Sent: Thursday, April 07, 2011 9:13 PM

Subject: Re: Landing the KIS TR-1

 	  Quote: 	
		   

 <bleuskyfly(at)teledynamix.com>



 Earlier in this thread I referred to the tendency of NACA 6-digit wing 

 profiles to prefer operation within their laminar flow design ranges. The 

 KIS TR-1 uses a modified 6-digit profile which can be described as 

 63(2)A-215.



 The 6-series was derived using an improved theoretical method that relied 

 mathematics to derive the geometrical shape required to realise the 

 desired pressure distribution. The goal of this approach was to design 

 airfoils that maximized the region over which the airflow remains laminar. 

 In so doing, the drag over a small range of lift coefficients can be 

 substantially reduced.



 To illustrate that, herewith attached a diagram in which the 

 characteristic drag "bucket" associated with laminar flow can be seen - in 

 this case for the NACA 64(2)-415 profile. This is from p.238 of 

 Torenbeek's "Synthesis of subsonic aircraft design".



 As can be seen from the diagram the drag increases rapidly as the lift 

 coefficient moves beyond the optimal range, which helps to slow down 

 rapidly but also results in high sink rate at non-optimal angle of attack. 

 However, these profiles do exhibit docile stall characteristics.



 A modification of the standard 6-digit series is the A-series in which the 

 curved contours of the trailing edge is replaced with straight contours 

 which run from about 80% of chord backwards - as manifested by flat 

 surfaces on the TR-1 flap and aileron. The TR-1 wing therefore nominally 

 represents a 63(2)A215 profile.



 Just one more reason to avoid high angles of attack during landing ...



 --------

 _________________________________________





 Read this topic online here:



 http://forums.matronics.com/viewtopic.php?p=336377#336377





 Attachments:



 http://forums.matronics.com//files/lift_and_drag_of_naca_airfoils_780.jpg

mantafs(at)earthlink.net
Guest

Posted: Fri Apr 08, 2011 7:27 am Post subject: Landing the KIS TR-1

According to Stinton the main gear contact angle aft of the CG should be alpha (at) 0.9 of Cl max plus 3 deg.  Using this I get about 5.25 deg.  Very close to your 5.5 to 6.5 deg.



Mark



--

mantafs(at)earthlink.net
Guest

Posted: Fri Apr 08, 2011 7:36 am Post subject: Landing the KIS TR-1

 	  Quote: 	
		  However I would like to clarify and emphasize that:



A) The danger / discomfort of having the nose abruptly drop while still 

airborne and close to the landing surface, and


	


Has this ever happened to anyone?  If so was it caused by stalling the wing?  If so was this due to "normal stall" or a ground effect problem?  I think that if this has happened it was due to normal stalling of the wing and the pilot should expect this and work to prevent it by watching airspeed and AOA.



 	  Quote: 	
		  B) The nuisance of not being able to hold the nose off after controlled main 

landing gear touchdown,




	


I am not so sure this is just a nuisance.  When a nose gear breaks due to repeated slamming it could get very expensive.



Mark

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