KIS-List Digest Archive

Mon 03/22/21


Total Messages Posted: 4



Today's Message Index:
----------------------
 
     1. 07:08 AM - Re: Re: Stalling the TR-1 ()
     2. 07:32 AM - Re: Re: Stalling the TR-1 ()
     3. 06:27 PM - Re: Re: Stalling the TR-1 (Galin Hernandez)
     4. 07:15 PM - Re: Re: Stalling the TR-1 (Galin Hernandez)
 
 
 


Message 1


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    Time: 07:08:10 AM PST US
    From: <craneplanes@gmail.com>
    Subject: Re: Stalling the TR-1
    Galin, I really appreciate all you do for this group and all the advice you give us. On the VG=99s, though, I need to respectfully disagree. The purpose of vortex generators (VG=99s) is to generate vortexes to =9Cenergize=9D the air and trip laminar flow air into turbulent flow. This allows the air to take a larger pressure differential before it separates (it can make a bigger, tighter bends before it separates and stalls). This is similar to the purpose of dimples on a golf ball. In order to be effective in tripping laminar flow to turbulent flow the VGs must be 1) in laminar flow air and 2) be large enough to be out of the boundary layer. (The boundary layer is the area of the flow right next to the skin when the airflow is slowed down due to friction with the skin. It grows in thickness the further from the leading edges of the nose and wings.) The horizontal stabs on the KR-1 and KR-4 are, like most single engine airplanes, in the propeller slip stream and at the back of the aircraft where the airflow is very turbulent. That means that VGs, especially the little ones (1=9D or so) are completely ineffective. Kent Pyle, whom I bought my TR-4 from and the world=99s worst airplane builder (4.5 years to rebuild and redo everything he did due to unsafe building materials and techniques), had them on the airplane and I removed them. Good news =93 Because the flow is so turbulent, the VGs probably don=99t add any significant drag, so they really aren=99t hurting anything except making it hard to clean the underside of the horizontal stab. When I bought I flew my flying deathtrap =F0=9F=98=8A (before realizing the need to rebuilt it), I simply could not hold the nose wheel off the ground, no matter how gently I touched the mains, and the nose would slam down. Following the advice of some TR-1 builders, I added 3=9D to the chord of the elevator to give me both more elevator and elevator trim authority (I couldn=99t trim the airplane slower than about 90-knots). Three years later, while doing taxi testing, I discovered that the real reason the nose would slam down on landing was not because of a lack of elevator authority, but because the main gear were loose. (Kent used bolts that were too long and he shanked them out, so the main gear where just hanging loose from the airplane in flight and would =9Cclick=9D forward when landing!) Point is =93 If you don=99t have enough elevator authority, more elevator area is the cure, not VGs. (Note - I have not flown the =9Cnew=9D airplane yet, so I=99m not sure what the impact of the additional elevator area is yet on a TR-4.) (BTW, I=99m a retired Navy test pilot and have a couple of degrees in Aero Engineering, specializing in aerodynamics. Just to establish a modicum of respectability with the group. =F0=9F=98=8A) -Doug Crane N302KM KIS Cruiser TR-4 From: owner-kis-list-server@matronics.com <owner-kis-list-server@matronics.com> On Behalf Of Galin Hernandez Sent: Friday, March 19, 2021 7:44 PM Subject: Re: KIS-List: Re: Stalling the TR-1 Yea, that's what I meant. On Fri, Mar 19, 2021 at 8:16 PM Graham Brighton <gbrighton@skymesh.com.au <mailto:gbrighton@skymesh.com.au> > wrote: <gbrighton@skymesh.com.au <mailto:gbrighton@skymesh.com.au> > Er .. Is that VG's .. under the 'Elevator' or 'Horizontal Stabilizer ' Graham TR1 # 080 -------------------------------------------------- From: "jeffbudner" <jeffbudner@gmail.com <mailto:jeffbudner@gmail.com> > Sent: Saturday, March 20, 2021 10:18 AM Subject: KIS-List: Re: Stalling the TR-1 <mailto:jeffbudner@gmail.com> > > > Thank you all for your responses. It's time for me to test the waters, > find some altitude and slowly work my way into a stall. Your feedback is > encouraging and much appreciated. I'm definitely considering VG's under > the elevator. > > > Jeff > KIS TR-1 #099 > > > Read this topic online here: > > http://forums.matronics.com/viewtopic.php?p=501024#501024 > > > -- > This email has been checked for viruses by AVG. > https://www.avg.com > List" rel="noreferrer" target="_blank">http://www.matronics.com/Navigator?KIS-List FORUMS - eferrer" target="_blank">http://forums.matronics.com WIKI - errer" target="_blank">http://wiki.matronics.com b Site - -Matt Dralle, List Admin. rel="noreferrer" target="_blank">http://www.matronics.com/contribution


    Message 2


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    Time: 07:32:15 AM PST US
    From: <craneplanes@gmail.com>
    Subject: Re: Stalling the TR-1
    Jeff, Galin's advice is perfect on learning the stall characteristics of your airplane. As you do it, you'll learn to listen as your airplane "talks to you", and get the feeling and sounds as you approach a stall. Another point - Stalls, in themselves, are not dangerous, especially in straight, "Hershey Bar" wings like we have. (Swept wings and abnormal, high performance wing shapes can be different.) The wings are designed to stall at the root (near the fuselage) before the tips, so the ailerons, being near the tips, are still effective, even when most of the wing is in stall. Also (and I'm not sure about the TR-1s, but on mine) the ailerons deflect upward much more than downward. This also helps reduce the possibility of a roll input causing the upward-going wing to stall and "snap" the airplane over (called a "snap stall"). The key is to have no yaw on the airplane. Keep the ball centered and use very little (or even better, no) ailerons to keep the plane level. All rudder, no stick. Keep these things in mind, and you can slow fly, slow stall, accelerated stall, deep stall it all day, and you'll be fine. Practice your recovery (think "push, push" on the stick and throttle), and you'll be an ace in your airplane in no time. And, your landings will be terrific because you'll know how to feel the stall without looking at an airspeed during your landing flair and just kiss the mains on the runway. (BTW, slow flight and stalling is one of the first things I do when flying a new airplane. Really gives you a feel for it.) -Doug Crane N302KM KIS Cruiser TR-4 -----Original Message----- From: owner-kis-list-server@matronics.com <owner-kis-list-server@matronics.com> On Behalf Of jeffbudner Sent: Friday, March 19, 2021 6:18 PM Subject: KIS-List: Re: Stalling the TR-1 Thank you all for your responses. It's time for me to test the waters, find some altitude and slowly work my way into a stall. Your feedback is encouraging and much appreciated. I'm definitely considering VG's under the elevator. Jeff KIS TR-1 #099 Read this topic online here: http://forums.matronics.com/viewtopic.php?p=501024#501024


    Message 3


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    Time: 06:27:54 PM PST US
    From: Galin Hernandez <galinhdz@gmail.com>
    Subject: Re: Stalling the TR-1
    Doug, All I know is that as I come to land, the nose drop with the VG's is much less than without them. Not completely gone but noticeably less. Maybe because at that point the engine is not generating much thrust so turbulence, as seen at the rear of the airplane is less, so they can make a difference. This is just me speculating on the reason for a noticeable difference in nose drop at touchdown speed. To expand on this, when I replaced my aluminum Sensenich propeller with a CATTO composite propeller (20lbs less weight on the nose) the entire problem went away. The slight shift in CG made a huge difference. Now I can grease it in on almost every landing, something I couldn't consistently do before. But then, I am just an "average joe" pilot. <HUGE SMILE> On Mon, Mar 22, 2021 at 10:09 AM <craneplanes@gmail.com> wrote: > Galin, > > > I really appreciate all you do for this group and all the advice you give > us. On the VG=99s, though, I need to respectfully disagree. > > > The purpose of vortex generators (VG=99s) is to generate vortexes t o > =9Cenergize=9D the air and trip laminar flow air into turbule nt flow. This > allows the air to take a larger pressure differential before it separates > (it can make a bigger, tighter bends before it separates and stalls). Thi s > is similar to the purpose of dimples on a golf ball. > > > In order to be effective in tripping laminar flow to turbulent flow the > VGs must be 1) in laminar flow air and 2) be large enough to be out of th e > boundary layer. (The boundary layer is the area of the flow right next to > the skin when the airflow is slowed down due to friction with the skin. I t > grows in thickness the further from the leading edges of the nose and > wings.) > > > The horizontal stabs on the KR-1 and KR-4 are, like most single engine > airplanes, in the propeller slip stream and at the back of the aircraft > where the airflow is very turbulent. That means that VGs, especially the > little ones (1=9D or so) are completely ineffective. Kent Pyle, who m I bought > my TR-4 from and the world=99s worst airplane builder (4.5 years to rebuild > and redo everything he did due to unsafe building materials and > techniques), had them on the airplane and I removed them. Good news =93 > Because the flow is so turbulent, the VGs probably don=99t add any > significant drag, so they really aren=99t hurting anything except m aking it > hard to clean the underside of the horizontal stab. > > > When I bought I flew my flying deathtrap =F0=9F=98=8A (before realizing t he need to > rebuilt it), I simply could not hold the nose wheel off the ground, no > matter how gently I touched the mains, and the nose would slam down. > Following the advice of some TR-1 builders, I added 3=9D to the cho rd of the > elevator to give me both more elevator and elevator trim authority (I > couldn=99t trim the airplane slower than about 90-knots). Three yea rs later, > while doing taxi testing, I discovered that the real reason the nose woul d > slam down on landing was not because of a lack of elevator authority, but > because the main gear were loose. (Kent used bolts that were too long and > he shanked them out, so the main gear where just hanging loose from the > airplane in flight and would =9Cclick=9D forward when landing !) Point is =93 If > you don=99t have enough elevator authority, more elevator area is t he cure, > not VGs. (Note - I have not flown the =9Cnew=9D airplane yet, so I=99m not sure > what the impact of the additional elevator area is yet on a TR-4.) > > > (BTW, I=99m a retired Navy test pilot and have a couple of degrees in Aero > Engineering, specializing in aerodynamics. Just to establish a modicum of > respectability with the group. =F0=9F=98=8A) > > > -Doug Crane > > N302KM > > KIS Cruiser TR-4 > > > *From:* owner-kis-list-server@matronics.com < > owner-kis-list-server@matronics.com> *On Behalf Of *Galin Hernandez > *Sent:* Friday, March 19, 2021 7:44 PM > *To:* kis-list@matronics.com > *Subject:* Re: KIS-List: Re: Stalling the TR-1 > > > Yea, that's what I meant. > > > On Fri, Mar 19, 2021 at 8:16 PM Graham Brighton <gbrighton@skymesh.com.au > > wrote: > > gbrighton@skymesh.com.au> > > Er .. Is that VG's .. under the 'Elevator' or 'Horizontal Stabilizer ' > Graham > TR1 # 080 > > -------------------------------------------------- > From: "jeffbudner" <jeffbudner@gmail.com> > Sent: Saturday, March 20, 2021 10:18 AM > To: <kis-list@matronics.com> > Subject: KIS-List: Re: Stalling the TR-1 > > > > > Thank you all for your responses. It's time for me to test the waters, > > find some altitude and slowly work my way into a stall. Your feedback i s > > encouraging and much appreciated. I'm definitely considering VG's under > > the elevator. > > > > > > Jeff > > KIS TR-1 #099 > > > > > > > > > > Read this topic online here: > > > > http://forums.matronics.com/viewtopic.php?p=501024#501024 > > > > > > > > > > > > > > > > > > > > > > -- > > This email has been checked for viruses by AVG. > > https://www.avg.com > > > ========== > List" rel="noreferrer" target="_blank"> > http://www.matronics.com/Navigator?KIS-List > ========== > FORUMS - > eferrer" target="_blank">http://forums.matronics.com > ========== > WIKI - > errer" target="_blank">http://wiki.matronics.com > ========== > b Site - > -Matt Dralle, List Admin. > rel="noreferrer" target="_blank">http://www.matronics.com/contributio n > ========== > >


    Message 4


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    Time: 07:15:33 PM PST US
    From: Galin Hernandez <galinhdz@gmail.com>
    Subject: Re: Stalling the TR-1
    FWIW with the VG's I can approach to land at under 80KIAS with still some elevator authority and touchdown at under 65KIAS something I couldn't do before. But the change in propeller made the absolute biggest difference. : ) On Mon, Mar 22, 2021 at 9:27 PM Galin Hernandez <galinhdz@gmail.com> wrote: > Doug, All I know is that as I come to land, the nose drop with the VG's i s > much less than without them. Not completely gone but noticeably less. May be > because at that point the engine is not generating much thrust so > turbulence, as seen at the rear of the airplane is less, so they can make a > difference. This is just me speculating on the reason for a > noticeable difference in nose drop at touchdown speed. > > To expand on this, when I replaced my aluminum Sensenich propeller with a > CATTO composite propeller (20lbs less weight on the nose) the entire > problem went away. The slight shift in CG made a huge difference. Now I c an > grease it in on almost every landing, something I couldn't consistently d o > before. But then, I am just an "average joe" pilot. <HUGE SMILE> > > On Mon, Mar 22, 2021 at 10:09 AM <craneplanes@gmail.com> wrote: > >> Galin, >> >> >> >> I really appreciate all you do for this group and all the advice you giv e >> us. On the VG=99s, though, I need to respectfully disagree. >> >> >> >> The purpose of vortex generators (VG=99s) is to generate vortexes to >> =9Cenergize=9D the air and trip laminar flow air into turbul ent flow. This >> allows the air to take a larger pressure differential before it separate s >> (it can make a bigger, tighter bends before it separates and stalls). Th is >> is similar to the purpose of dimples on a golf ball. >> >> >> >> In order to be effective in tripping laminar flow to turbulent flow the >> VGs must be 1) in laminar flow air and 2) be large enough to be out of t he >> boundary layer. (The boundary layer is the area of the flow right next t o >> the skin when the airflow is slowed down due to friction with the skin. It >> grows in thickness the further from the leading edges of the nose and >> wings.) >> >> >> >> The horizontal stabs on the KR-1 and KR-4 are, like most single engine >> airplanes, in the propeller slip stream and at the back of the aircraft >> where the airflow is very turbulent. That means that VGs, especially the >> little ones (1=9D or so) are completely ineffective. Kent Pyle, wh om I bought >> my TR-4 from and the world=99s worst airplane builder (4.5 years t o rebuild >> and redo everything he did due to unsafe building materials and >> techniques), had them on the airplane and I removed them. Good news =93 >> Because the flow is so turbulent, the VGs probably don=99t add any >> significant drag, so they really aren=99t hurting anything except making it >> hard to clean the underside of the horizontal stab. >> >> >> >> When I bought I flew my flying deathtrap =F0=9F=98=8A (before realizing the need >> to rebuilt it), I simply could not hold the nose wheel off the ground, n o >> matter how gently I touched the mains, and the nose would slam down. >> Following the advice of some TR-1 builders, I added 3=9D to the ch ord of the >> elevator to give me both more elevator and elevator trim authority (I >> couldn=99t trim the airplane slower than about 90-knots). Three ye ars later, >> while doing taxi testing, I discovered that the real reason the nose wou ld >> slam down on landing was not because of a lack of elevator authority, bu t >> because the main gear were loose. (Kent used bolts that were too long an d >> he shanked them out, so the main gear where just hanging loose from the >> airplane in flight and would =9Cclick=9D forward when landin g!) Point is =93 If >> you don=99t have enough elevator authority, more elevator area is the cure, >> not VGs. (Note - I have not flown the =9Cnew=9D airplane yet , so I=99m not sure >> what the impact of the additional elevator area is yet on a TR-4.) >> >> >> >> (BTW, I=99m a retired Navy test pilot and have a couple of degrees in Aero >> Engineering, specializing in aerodynamics. Just to establish a modicum o f >> respectability with the group. =F0=9F=98=8A) >> >> >> >> -Doug Crane >> >> N302KM >> >> KIS Cruiser TR-4 >> >> >> >> *From:* owner-kis-list-server@matronics.com < >> owner-kis-list-server@matronics.com> *On Behalf Of *Galin Hernandez >> *Sent:* Friday, March 19, 2021 7:44 PM >> *To:* kis-list@matronics.com >> *Subject:* Re: KIS-List: Re: Stalling the TR-1 >> >> >> >> Yea, that's what I meant. >> >> >> >> On Fri, Mar 19, 2021 at 8:16 PM Graham Brighton <gbrighton@skymesh.com.a u> >> wrote: >> >> gbrighton@skymesh.com.au> >> >> Er .. Is that VG's .. under the 'Elevator' or 'Horizontal Stabilizer ' >> Graham >> TR1 # 080 >> >> -------------------------------------------------- >> From: "jeffbudner" <jeffbudner@gmail.com> >> Sent: Saturday, March 20, 2021 10:18 AM >> To: <kis-list@matronics.com> >> Subject: KIS-List: Re: Stalling the TR-1 >> >> > >> > Thank you all for your responses. It's time for me to test the waters, >> > find some altitude and slowly work my way into a stall. Your feedback >> is >> > encouraging and much appreciated. I'm definitely considering VG's unde r >> > the elevator. >> > >> > >> > Jeff >> > KIS TR-1 #099 >> > >> > >> > >> > >> > Read this topic online here: >> > >> > http://forums.matronics.com/viewtopic.php?p=501024#501024 >> > >> > >> > >> > >> > >> > >> > >> > >> > >> > >> > -- >> > This email has been checked for viruses by AVG. >> > https://www.avg.com >> > >> ========== >> List" rel="noreferrer" target="_blank"> >> http://www.matronics.com/Navigator?KIS-List >> ========== >> FORUMS - >> eferrer" target="_blank">http://forums.matronics.com >> ========== >> WIKI - >> errer" target="_blank">http://wiki.matronics.com >> ========== >> b Site - >> -Matt Dralle, List Admin. >> rel="noreferrer" target="_blank">http://www.matronics.com/contributi on >> ========== >> >> >>




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