Elevator Gap Seals. DOES IT WORK ON A KITFOX?

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Alex Di Sessa

Alex Di Sessa

Күн бұрын

Пікірлер: 130
@TrentonPalmer
@TrentonPalmer 6 жыл бұрын
Haven't seen this until now. Looks like your wing is stalling before your elevator because the flow over the elevator seems to remain for the most part attached even during the stall. So if you aren't having issues with stalling the tail then you won't see much (or any) improvement. So to lower stall we need to work on slowing the wing down, VGs in the right spot seem to help but its a mixed bag depending on who you talk to.
@AlexDiSessa
@AlexDiSessa 6 жыл бұрын
Yes. I think that's what's happening. VG's are next..
@shangqijian6655
@shangqijian6655 4 жыл бұрын
@@AlexDiSessa Aircraft manufacturers design the airplanes on purpose to stall wing before the horizontal stabilizer so you have some authority during stalls. If the horizontal stabilizer stalls you could lose pitch control and be in a very dangerous situation.
@chuckpreston4981
@chuckpreston4981 6 жыл бұрын
It appears, from tests conducted by Trent Palmer and others, that the best results in lowering stall speeds come from vortex generator installation at around 4-5% of chord on the upper wing surface as well as on the underside of the elevator. This makes sense since the critical component in a stall is the airflow to the wing. Simply improved airflow to the elevator, while nice, does not regulate stall speeds.
@vg23air
@vg23air Жыл бұрын
kzbin.info/www/bejne/oHmbmaiifMmWhK8si=J8jMtOdB2hYiiF_S
@TRabbit1970
@TRabbit1970 4 жыл бұрын
Those gap seals are more likely reducing drag, if anything. Placing VGs on your tail might be more effective at improving control authority at high AOA.
@douglascloud4484
@douglascloud4484 4 жыл бұрын
INTERESTING, keep up the informational videos. thanks awesome videos
@flyboybbq1718
@flyboybbq1718 6 жыл бұрын
Alex, someone may have already made a comment similar to this. If so, sorry. The gap sseals may give you a little better cruise, but your elevator was not stalling, so it works well enough. I would install the VG's on your wing. That will probably result in a slower stall speed where your elevator becomes less effective. Once the VG's are on, go try the same experiment you tried in this video. If you ryun out of elevator authority, then install VG's on the horizontal stab and see if that gets you more elev authority. Your experiment was well thought out, and enjoyable to watch.
@jonathanholland1304
@jonathanholland1304 9 ай бұрын
Great videos. My only comment (I have a Model 4) is that the purpose of the gap seals isn’t so much to reduce stall speed, it’s to be able to increase the angle of attack in the very last stages of a three point landing. Without them, lots of Kitfoxes with quite big elevator gaps, ‘spill’ a lot of air through that gap, and render the elevator ineffective quite early, and therefore making it hard to get the tail right down into a full three point landing. Gap seals (I’ve put them on all three of my Kitfoxes) definitely help a lot with getting that tail down lower in the final stages of a flare, and making three point landings much easier to achieve, rather than running out of elevator authority, and then finding the mains touch first, and then the tail drops as a result. As the tail drops, if the airspeed is low enough then this is fine, but if it’s a little too high, the angle of attack increases, and there’s a chance of a small balloon. As I said, great videos, but these gap seals aren’t about stall speed, they’re about achievable angle in the very final stages of three point landing. 👍🏼👍🏼
@doncatchpole7370
@doncatchpole7370 4 жыл бұрын
Thanks for the education.
@AlexDiSessa
@AlexDiSessa 4 жыл бұрын
Any time!
@stanRmeyer
@stanRmeyer 6 жыл бұрын
It may just slightly lower the drag for a little more speed or economy
@feliperodriguezreyes3236
@feliperodriguezreyes3236 6 жыл бұрын
Very nice Alex,,
@flexairz
@flexairz 6 жыл бұрын
The force acting on the elevator by the air flow is from the bottom of the elevator upwards. So the air coming though the gap comes from the underside where the higher pressure air is.
@louisbelzil3105
@louisbelzil3105 6 жыл бұрын
The elevator usually exerts a downforce. The higher pressure is on top.
@tztz1949
@tztz1949 6 жыл бұрын
Your efforts are noble. But, look at sailplane gap seals. If you mimic the installation you should see less drag on the horizontal and much more efficiency on the main wing. (if you can have gap seals on large gaps). Do not only seal one side or 1 wing. Very dangerous differential drag will result.
@jaywhite9249
@jaywhite9249 6 жыл бұрын
Gap seals will give you more pitch authority during the landing flare. I installed them on my kitfox and the difference is noticeable. They don't improve slow flight.They are just for the authority in the landing configuration.
@allankrosner679
@allankrosner679 4 жыл бұрын
Jay White Wha did you use fir a gap seal? I am working on a Kitfox 5 project.
@olympiomendes
@olympiomendes 5 жыл бұрын
Parabéns pela iniciativa Alex. Você conhece quem monte o kitfox no Brasil? Obrigado.
@AlexDiSessa
@AlexDiSessa 5 жыл бұрын
nao conheco! abracos.
@Kalimerakis
@Kalimerakis 6 жыл бұрын
Where can I find this shirt? @10:00 is it honda aviation?
@AlexDiSessa
@AlexDiSessa 6 жыл бұрын
Honda Shirt. Got it as OSH
@Kalimerakis
@Kalimerakis 5 жыл бұрын
@@AlexDiSessa is that Oshkosh? I'll see what I can find. Great shirt! Thanks!
@snaprollinpitts
@snaprollinpitts 6 жыл бұрын
I wonder if you would do the test again, except this time test for max air speed with the seal on the both the stab/ elevator, and fin/rudder.
@kenhurley4441
@kenhurley4441 6 жыл бұрын
Gap seals should increase cruise/max speed.
@mts592
@mts592 6 жыл бұрын
Hi Alex, I'm actually surprised at no noticable difference too! I compared the moving strings in your side by side videos & couldn't see a major change. I've always been told it would help & I still believe it must help. It has to smooth out the airflow and give some advantage. Keep us posted.
@williamtaylor4024
@williamtaylor4024 6 жыл бұрын
Have you tried VG's on the bottom of the horizontal?
@AlexDiSessa
@AlexDiSessa 6 жыл бұрын
Will do that next!
@nzsaltflatsracer8054
@nzsaltflatsracer8054 6 жыл бұрын
Since it's the main wing that stalls, the only effect you will possibly feel is low speed elevator effectiveness assuming it's not in the shadow of the main wing at that time. There will be a slight decrease in drag but you will never feel that in the seat of your pants but might see it in fuel consumption on extended flights.
@chuckw1596
@chuckw1596 5 жыл бұрын
Have your buddy model it in solidworks and you will see the cavitation and less laminar flow. Play with the gap size and it can get dramatic at higher speeds. Some planes even have vortex generators on the elevator to keep the flow from detaching or buffeting.
@bradsmith4004
@bradsmith4004 6 жыл бұрын
I put gap seals on my Kitfox V and it made a BIG difference in flare in landing. Especially when you add a little power while landing behind “the power/drag curve” which helps coming in slow. I have a Continental IO-240 up front so I’m a little nose heavier than yours. Putting VG’s on the main wing made the difference in stall speed on mine.
@av8r3400
@av8r3400 6 жыл бұрын
I sealed the gaps with tape on my IV-1050 and had a noticeable difference in the ability to flair with flaps. The stall did not seem effected, but the authority was higher at low speed with flaps deployed. That plane has a smaller elevator than your V (Five) does, so that may be a difference. I built my current IV-1200 with a much larger, custom elevator and rudder so I have not tried (or felt the need) to seal the gaps on this plane.
@AlexDiSessa
@AlexDiSessa 6 жыл бұрын
av8r3400 good reference. I came for few touch and go’s with the gap seal but could not feel any difference at all.
@jeffstone7912
@jeffstone7912 5 жыл бұрын
I’m not a pilot, but I would think The gap seal would make the surface a little cleaner. I think on an airplane with a higher cruising speed the gap seal would help with fuel economy. Your airplane probably cruises at about 100 mph? On a plane with a plane The cruise is 200 mph or faster the difference would be much more significant. It is fun to experiment. Fly safe.
@DougOrDouglas
@DougOrDouglas 6 жыл бұрын
Did you build or buy your plane? I hope to someday build own of my own, also if you don't mind me asking how much did it set you back?
@ljbern1
@ljbern1 6 жыл бұрын
Interesting. Are you flying out of Concord, Ca.?
@AlexDiSessa
@AlexDiSessa 6 жыл бұрын
Yes, CCR
@ljbern1
@ljbern1 6 жыл бұрын
Alex Di Sessa Thank you.
@eclipser2004
@eclipser2004 5 жыл бұрын
Might get a bit of an increase in cruise speed I would say. Not sure about stall speed though. The Kitfox stalls slow enough already.
@terryedmond4492
@terryedmond4492 5 жыл бұрын
Adding an half inch to your elevator length would be where it's effective. That slight turbulence around the gap just leaves a little low pressure area where it doesn't matter.
@paulbergman8228
@paulbergman8228 6 жыл бұрын
Interesting study; I only saw a little more flutter on the outboard edge of the elevator tab with no gap seals, so there is more tip vortex interruption flow without the seals. Try fewer yarns, and put some over the gap and off the trailing edge and on the very tip edge of the stabilizer and the elevator tab, and see if it is different. In sailing, it is the yarns at the trailing edge that show how much airflow is reversing or backflowing onto the low pressure side, and especially at the top of the sail where the chord is less. I will ask Jerry Burr (Cub) who did the flight tests for Micro Aerodynamics. He did about 30+ flights in each configuration with the wing VG’s at different percentages from the leading edge of the wing, but not sure about the elevator. I’ll ask him. We live in Burlington, WA and fly out of KBVS, a few miles from 74S (Anacortes) where Micro Aero is located. I serve on a board with Becky, so I see them regularly. I have flown in his plane with his wife, so I know how it feels on slow landing. I took a series of pics from the ground while his wife was landing, and it just seemed to almost stop before setting down, like 25+ or - knots as she pulled the stick full back. Jerry was the first one to have vortex generators when he won the Valdez STOL competition a few years back. Now that everyone has them, he said going to Alaska is a moot point, especially with the custom set-ups for only STOL competitions. If you observe some seaplanes, they put a vertical tip fence on the elevator to give it more authority; my guess is that helps to give a higher angle to attack to get up on a surface plane on the water on takeoff. The 747 that flew the space shuttles, had the same vertical fences on the elevator, but then look at the airflow interruption issues they had to overcome. My aviation email is dirkaws@gmail.com. That is my dogs email 🐾 an American Water Spaniel...LOL
@AlexDiSessa
@AlexDiSessa 6 жыл бұрын
Thanks for the comment. Vg's are way to go.
@Shadow63Wolf
@Shadow63Wolf 5 жыл бұрын
All gap seals do is stop the flow between pressure differences. Think about what you are actually sealing or imagine your wing with a big slot down the middle of it. Which is partly how some flaps are mounted. They can make some types of flaps and control surfaces more effective by preventing the flow to the other side. To really see this this with tufts, you would have had to mount them right over the gap. Depending on the direction the elevator is working, the tufts would be either sucked into the gap or blown out. Gap sealing stops this. To actually prove it you could make your own wind tunnel, or even observe the elevator during run-up and moving the elevator with a significant air flow.
@uniaddict
@uniaddict 6 жыл бұрын
From what I understand, your wing is what controls the stall speed. Closing the gap between your elevator and horizontal stabilizer should give you more control authority at slower speed, however, you must have the trim not maxed out then you will be able to have more authority at those slower speeds because the of the gap seal. You should be able to pull a higher angle of attack with the gap seal at slower speeds but your wing will still stall at the same speed. It is odd that your power on stalls were no slower, although that is indicated airspeed, right? Or was that your true airspeed? Man its hard to get your thoughts out in a youtube comment haha. I still love the videos! Keep up the awesome work!
@AlexDiSessa
@AlexDiSessa 6 жыл бұрын
Kellan Rothfus good point. The idea was not to compare the airspeeds. That was just an additional reference for me. I wanted to visually see with the strings if they were any different with or without the gap seal. As for the trim, I always land fully trimmed. I wanted to replicate that. Can’t land the Kitfox without fully trimmed.
@Ash-vw1gg
@Ash-vw1gg 6 жыл бұрын
The stall occurs at the critical angle of attack and can happen at a variety of air speeds so I don’t think it would improve his AoA but you’re right about more control authority. I’m also curious if adding the gap seal would make control forces tougher on this configuration since there doesn’t seem to be any counter weights and if the air passing through the gap would act as that opposing force. I’m not sure how you could test control authority/speed without some precise tools. Maybe time to achieve attitude compared to speed with and without the gap seal?
@AlexDiSessa
@AlexDiSessa 6 жыл бұрын
Yeah not sure. Didn't feel any different but some good comments all around.
@DanYocum
@DanYocum 4 жыл бұрын
Ash Bobye this. I put gap seals on my elevator *and* ailerons on my Pietenpol Air Camper and the control authority was significantly increased for both.
@kitfoxn990tt5
@kitfoxn990tt5 6 жыл бұрын
As others have said, gap seals are only expected to increase elevator authority at very low speeds. In order to test for this you need to put gap seals on BOTH elevators and then test for stick force and motion during the landing flare. I put gap seals on my SS7 and noticed a definite difference in a low speed 3-point landing flare; no difference in a wheel landing.
@AlexDiSessa
@AlexDiSessa 6 жыл бұрын
I could not notice any difference in mine, even after several landings with it at very, very low speeds.
@ChuckJ1944
@ChuckJ1944 5 жыл бұрын
Is the thickness of the stabilizer the same as the elevator. If the elevator is slightly less thick, the air may not get a chance to flow into the gap.
@teddyhouser1207
@teddyhouser1207 6 жыл бұрын
I have not done any scientific testing with the gap seals on mine other than a lot of hours without and now with them. Before the seals, mine would drop the nose hard when flaring at 40 mph ASI landing. It was consistent and of course power would help keep the nose stable in the flare. With the gap seals it is no where near as drastic of a nose drop and less power is required which now translates into a short STOL rollout. In my opinion, I see no need to leave them unsealed though it will fly just fine either way. My next step is to seal my rudder gap. See how that affects things.
@AlexDiSessa
@AlexDiSessa 6 жыл бұрын
Which plane do you fly? I could not notice any chance with or without on mine!
@teddyhouser1207
@teddyhouser1207 6 жыл бұрын
@@AlexDiSessa I fly a model 4 1050 gross weight with 80 horse 912. Flair is the only place I can tell a difference. Elevator authority goes deeper into the flair without having to add power. I still add power though because with my small rudder, it doesn't work well to steer with complete power off.
@yodaiam1000
@yodaiam1000 6 жыл бұрын
I think it makes sense that it didn't have an effect on the main wing performance or on the tail air flow. I suspect the horizontal stabilizer has lower stall speeds than the main wing (the tail is often even inverted in some cases). You want the horizontal stabilizer to stall way after the main wing so that you don't loose elevator authority at slow air speeds or in stalls. However the gap seal might improve drag numbers (maybe not by much). I like that you experimented with it and got results that you weren't expecting. Why experiment if the result are always what you expect.
@briangarcia8986
@briangarcia8986 6 жыл бұрын
You should try the gap seals on your ailerions. Gap seals on the tail feathers is just cleaning up the airframe with maybe a little less deflection for a given maneuver. This is hard to measure with any kind of accuracy. Put those gap seals on your ailerons and you will notice an immediate increase in roll rate. And that will put a smile on your face. Pick a few airspeeds at let say fifty, sixty and seventy. Go fly with no gap seals and roll 45 degrees left and right. Use a instrument on your panel that's square. Screws that hold it in place are straight up and down when your at a 45. Time the roll rate with the rudder neutral at these, different speeds suggested. Add the gap seals on both ailerons and repeat the same exercise. I'm pretty sure you will find improvement in roll rate and with the rudder and elevator sealed a little better cruise speed at a given setting. Who knows you may end up with a little less adverse yaw have fun share what you find. Thanks! From the great lakes state of Michigan.
@fredstork
@fredstork 6 жыл бұрын
Hi Alex, great video and I like your approach. I did not expect any significant difference in stall speed but you mention, in the beginning of the video, the expectation of increased rudder authority. Another expected outcome would be reduced drag. You don't mention the eventual effect on rudder authority that I would expect to be most noticeable during landing flair. Did you feel any difference, and if so, is it worth the effort (we still have to see an esthetic solution...)? Thanks for sharing and keep up the good work and the videos comming!
@AlexDiSessa
@AlexDiSessa 6 жыл бұрын
No, did not feel any difference at all in rudder.. it was basically the same.
@cmtetaboaco
@cmtetaboaco 4 жыл бұрын
Minha dúvida seria sobre o voo de cruzeiro, eficiência, arrasto,... mas o modelo de acetato, que mantém continuo o perfil, o Cirrus vem com isso nos ailerons, mas pra ver isso teria que por a lã passando do início ao fim do elevator! Outra acft q tem isso é o Edraer wt9
@GenasysMech
@GenasysMech 5 жыл бұрын
Hi, It's always been my understanding gap seals reduce induced drag, not improve control effectiveness. Probably could only be measured by a small improvement in cruise speed. Very nice Kitfox you have there.....
@tomasprihoda8857
@tomasprihoda8857 6 жыл бұрын
May I ask a question? I am not going through other comments, so sorry if you have already discussed this. The gap seal shoud increase the elevator authotity, which in my understanding is not about stall speed or control forces on the control stick. It should increase the slope of lift curve of the HT. And this should have an effect at the elevator deflections. In other words, you stall the aircraft at the same speed with the same control stick force but with lower elevator deflection. Did you measured it? Thx. Tomas
@AlexDiSessa
@AlexDiSessa 6 жыл бұрын
The stall speeds were reference only for myself. Did not measure it.
@tomasprihoda8857
@tomasprihoda8857 6 жыл бұрын
@@AlexDiSessa did you measured elevator deflection with gap seal and without? Thx.
@MrCarpediempilot
@MrCarpediempilot 6 жыл бұрын
Your main wing will stall at the same angle of attack weather you have a gap seal or not. You may have marginally more elevator authority hard to say. A gap seal will clean up a little bit of drag on your airplane and make it slightly faster for a given speed but that would be about it. You may get some Benefit from some vortex generators on the main wing and on the bottom of the horizontal stabilizer. Just my 2 cents. Nice video thanks for sharing.
@AlexDiSessa
@AlexDiSessa 6 жыл бұрын
Yeah will try the vortex generators next!
@jasonsneed3179
@jasonsneed3179 6 жыл бұрын
But, if he does not have enough elevator authority to get to the critical AOA then the gaps seals would change where the stall occurs...
@MrCarpediempilot
@MrCarpediempilot 6 жыл бұрын
True but he was able to stall the main wing in the video so it would appear that he has enough authority in the main wings current configuration. Jut my thoughts. I am not aerodynamic expert by any stretch of the imagination but thats what I am thinking. I could be wrong.
@GWAYGWAY1
@GWAYGWAY1 6 жыл бұрын
Your wings stalls before the elevator loses authority, gap seals reduce drag not improve the elevator effect. The same with the vertical fin gap. Vortex generators along the top of the wing will reduce stall speed And the elevator would gain from having them along the bottom . Maybe worth trying next?
@AlexDiSessa
@AlexDiSessa 6 жыл бұрын
Yep, that's the plan.
@heydonray
@heydonray 5 жыл бұрын
Others have said it: Gap seals are about elevator authority only, not stall speed. On my own plane (Pitts) elevator authority at all speeds was dramatically improved, with corresponding reduction in elevator forces. If you’re not running out of elevator or are happy with elevator forces in your type of flying, then gap seals would likely be of little or no benefit IMO.
@ashsmitty2244
@ashsmitty2244 5 жыл бұрын
That’s exactly what I learned too.
@stonesofetown6767
@stonesofetown6767 5 жыл бұрын
I’m not sure how gap seal helps with stall when installed on the elevator. On the wing they increase the lift because less high pressure air from the bottom of the wing can find its way to the top of the wing. The more you keep the flow laminated the better it is was my understanding?
@AlexDiSessa
@AlexDiSessa 5 жыл бұрын
They don't. I wanted to learn more about how they affect elevator authority. I was curios about the stall speeds.
@1234SERGIO4321
@1234SERGIO4321 6 жыл бұрын
Hey Alex, are you from São Paulo, Brazil ?? I saw the "São Paulo Futebol Clube" flag in your hangar.
@AlexDiSessa
@AlexDiSessa 6 жыл бұрын
yep!!
@DJAlienCoreWatcher
@DJAlienCoreWatcher 6 жыл бұрын
You would want to study wing flap gaps if anything to effect stall.
@AlexDiSessa
@AlexDiSessa 6 жыл бұрын
I wasn't trying to improve stall. I was trying to see if I get more elevator control. The stall speeds were for my reference only.
@russellfreeman4931
@russellfreeman4931 6 жыл бұрын
The gap seals on the horizontal stab and elevator have nothing to do with stall speed. Your main wing will stall at the same angle of attack no matter what the tail is doing. The gap seals on the tail only aid in providing more control authority. This only comes into play if your main wing is still flying, but you lose controllability from the elevator. This usually only happens on stol aircraft if you're main wing is so good (with VG's, airfoil, or slats), that your tail stalls prior to the main wing.
@AlexDiSessa
@AlexDiSessa 6 жыл бұрын
yes, Vg's are next
@hotrodray9884
@hotrodray9884 5 жыл бұрын
Elevator effectiveness should not affect the stalling AOA of the main wing. Was the elevator full up at each stall?? There appeared to be a slight difference on the split screen. The high pressure air from the upper side of the horizontal stabilizer falls through the gap to the lower pressure side of the elevator reducing effectiveness. A gap seal would stop this. VGs on the bottom ?? Ill bet gap and VGs would help the rudder too.
@dactel2
@dactel2 4 жыл бұрын
The horizontal stabilizer is an upside down wing so when you're flying at higher AOA (i.e. slower flight), the horizontal stabilizer is flying at a lower AOA, and vice versa. I think this is probably why you didn't see any difference....
@joesparky1
@joesparky1 6 жыл бұрын
I am confused. You are adding gap seals on the horizontal stabilizer and expecting it to have an affect on the main wings stall speed? How?
@AlexDiSessa
@AlexDiSessa 6 жыл бұрын
Not trying to get an effect on stall speeds. I emphasized that on the video. The stall speed was just a reference point as curiosity. The goal was to visually observe if there’s a difference in the airflow with and without the seal. I could not observe a significant difference visually nor with the feel.
@creekboy2893
@creekboy2893 6 жыл бұрын
I like the Honda jet shirt!
@JeanLucCoulon
@JeanLucCoulon 4 жыл бұрын
To raise the authority why not to add vortex generators UNDER the horizontal plane?
@damham5689
@damham5689 6 жыл бұрын
Not that it would matter in your test because you're using the taped in strings throughout the test, but I am wondering if the bumps where strings are taped on and all the strings themselves wouldn't disrupt airflow. Much like micro VGs do ? Wonder if anyone has done a real test on that? Especially with that many strings and tape bumps. Just curious.
@AlexDiSessa
@AlexDiSessa 6 жыл бұрын
Good question. Not sure!
@NicHolmes
@NicHolmes 6 жыл бұрын
On my kitfox 4 the gap seals are a neccessary addition to obtain 3 point attitude on touchdown with flaps. Without gap seals you can pull full elevator and not round out to 3 point in the stall
@williamtaylor4024
@williamtaylor4024 6 жыл бұрын
Check your cg.
@NicHolmes
@NicHolmes 6 жыл бұрын
My CoG was done a few months back, and it sits directly below the pilots backrest.
@jamesjanssen2378
@jamesjanssen2378 6 жыл бұрын
Nic >>> That is really strange . Only know S-Cubs so really hard to understand .
@NicHolmes
@NicHolmes 6 жыл бұрын
@@jamesjanssen2378 only thing I can put it down to is that the kitfox 4 is a shortage fuselage than the 5 so the tail enters "dirty" air sooner and without prop wash to help just doesnt have the authority
@jamesjanssen2378
@jamesjanssen2378 6 жыл бұрын
@@NicHolmes > Thanks , makes sense. I didn't know about that problem. Never flew the KITFOX.
@GeorgeHardin
@GeorgeHardin 6 жыл бұрын
HI Alex, love your videos. I have a Kitfox Lite Squared (Same as model 4). I stall at 34-36mph, with flaps, power off. My elevator gaps are tighter than yours. I am at LHM, we could meet at VCB and compare construction and maybe go for a ride?
@AlexDiSessa
@AlexDiSessa 6 жыл бұрын
yeah, love to!
@raymondkoonce5827
@raymondkoonce5827 6 жыл бұрын
The horizontal stabilizer is essentially an inverted wing, and any wing can be forced into a stall. However, stalling the horiz. stab would not be the greatest idea in the world. I think Roy LoPresti was heavily involved in gap seals, among many other things, but his were mainly in the arena of increasing speed. Witness the Mooney 201. VGs may be the best solution for your purposes. I'm just a pilot, though, not an aeronautical engineer, so temper my comments with a grain of salt.
@volandoando123
@volandoando123 5 жыл бұрын
You should look at higher cruise speed not stall speed
@BrianGochnauer
@BrianGochnauer 6 жыл бұрын
I've never heard of anyone thinking gap seals improved stalls. I've only heard using gap seals to increase airspeed (cruise) and reduce drag.
@Jack-ne8vm
@Jack-ne8vm 6 жыл бұрын
If you synchronized before/after videos to airspeeds...
@AlexDiSessa
@AlexDiSessa 6 жыл бұрын
yeah it is a hard one to do!
@peterhancox5268
@peterhancox5268 6 жыл бұрын
You definitely need gap seals on your Ailerons, such a big gap on a Kitfox:)
@hotrodray9884
@hotrodray9884 5 жыл бұрын
Every little bit counts but at 100 mph cruise... a little is a little. Look up F11 wax and give it a try.
@robertfisher4150
@robertfisher4150 6 жыл бұрын
Your science is good. If you wanted more quantitative results, putting arc scales under the “tufts” might help, but unnecessary. I think you learned what you could. Actual measurement differences would be no more conclusive than what you saw. Good stuff! Well done.
@russellfreeman4931
@russellfreeman4931 6 жыл бұрын
No, his science was terrible. His execution was an attempt. His premise was to test a stall speed decrease. He didn't find it because gap seals have no effect on stall speed. They only increase control authority, and perhaps, a bit of cruise speed. Back to his test. The wing will always stall at the same angle of attack, without care to what the tail is doing. Hence his nearly identical findings. His results and analyzation of those were good, but his findings on the outcome were false based on the premise of the test. He had no change in stall speed. Proven correct lol. But he did not measure what gap seals are supposed to improve, which is control authority.
@robertlafnear4865
@robertlafnear4865 6 жыл бұрын
I would say looking at the gap on your plane you would have nothing to loose and everything to gain....... V.G.'s are a good addition, put them on and re-test your stall and post for all of us with a KitFox ... and your tail looks like a mop (lol).
@AlexDiSessa
@AlexDiSessa 6 жыл бұрын
Robert Lafnear will test that next.
@robertlafnear4865
@robertlafnear4865 6 жыл бұрын
GREAT, ... will be glad to see the results... I'm betting a nice reduction of that stall speed.... have fun flying , fly safe.
@dougmouton2309
@dougmouton2309 5 жыл бұрын
The whole idea is quicker rudder and elevator control
@haraldweltzin5117
@haraldweltzin5117 5 жыл бұрын
MY FRIEND BUILT A FLY BABY AND THE EXPEDIANT OF COVERING THE GAP OF HIS FLING WIRES WHICH WERE A HALF INCH APART MADE A 10 MILE PER HOOUR DIFFERENCE IN HIS CRUISE SPEED.
@wudalo24
@wudalo24 10 ай бұрын
Gap seals are to increase elevator authorithy
@Thestripper1
@Thestripper1 5 жыл бұрын
One would expect that gap seals make a difference in fuel consumtion.
@briangarcia8986
@briangarcia8986 6 жыл бұрын
Now I get it why you were concentrating on you tail feathers you probably have the stol type flap ailerons set up on your kit fox. Don't put gap seals on that system it would be a disaster! Maybe my suggestions will help someone with cub like aircraft?
@marysmith4576
@marysmith4576 6 жыл бұрын
Nice experiment, but the results were pretty obvious before you took off. The only thing the seals are going to do is help clean up the drag, but in the case of a kitfox it should help your burn rate not so much the overall speed... its a bush plane after all.
@flyingmaniac3827
@flyingmaniac3827 6 жыл бұрын
Alex i have been watching for a wail silently but i have to say something now, elevator gap is already spiting hair for a guy that is capable of 20 knots speed of approach at low wing loading and high angle of attack , and i think it is more to reduce parasitic drag coefficient , sizing up the elevator is a more logical approach , if you can't put a fox on a 3 point on the original elevator your balance is off , in your case it is futile , do you even know your wing loading ? , the fox with the normal wing is not meant for speed under 40 , your wing exceed the lift/weight equilibrium plain and simple , a lower wing loading would permit the laminar flow to brake less farther alf of the wing profile and maintain lift equilibrium at higher angel of attack , putting VG could help a bit by forcing the laminar flow to the profile preventing the bubble brake formation but not by a hole lots , reducing the weight or changing for the STI wing set is your only sane and logical solution if you goal is to get in short filed landing if not just keep it the way it is , i did the polar calculation on the fox wing profile and it's a good profile it actually have a better curve then the USA31B very capable of 15 degree plus angle of attack and the camber in it help a fair bit to but at the wing loading you carry it as it's limit .
@AlexDiSessa
@AlexDiSessa 6 жыл бұрын
I don't have a problem doing a 3 point,, do it all the time. This was to experiment if I could visually see any difference with and without it. Some said that you have more control during flare with the gap seal. I wanted to see for myself but could not visually see or feel that extra "control"... Vg's hope will make the effect I am looking for! Thanks for the comment.
@flyingmaniac3827
@flyingmaniac3827 6 жыл бұрын
i was referring more to the guy that says he could not do a 3 point with out gap bridge lol,VG will give you a couples Knots more for sure , keep us updated, and getting familiar with throttle burst to keep the angle jut a bit higher is a good Technic to acquire , it feels wrong and un natural but if you can get some one like Trent or a instructor familiar wit it it would be a game changer , you could stop before the runway threshold like you where trying to do .
@terryedmond4492
@terryedmond4492 5 жыл бұрын
If insignificant difference, then don't bother. We strive for perfection, but theory doesn't dictate practicality. Good testing. I assume you're an engineer. I'm curious about your heritage, Spanish, Greek, Italian, Iranian? Brazilian, eh? (no help)
@luanraasch5960
@luanraasch5960 6 жыл бұрын
Essa bandeira do São Paulo tu arrumou aonde amigo ?🤣
@AlexDiSessa
@AlexDiSessa 6 жыл бұрын
No estadio!!
@luanraasch5960
@luanraasch5960 6 жыл бұрын
@@AlexDiSessa 🇧🇷♥️
@ukuletion1
@ukuletion1 5 жыл бұрын
I am more interested in stabilizer redundancy...looks be damned:)
@Nishirasu
@Nishirasu 6 жыл бұрын
cara o mano é tricolor =D
@russmontgomery5211
@russmontgomery5211 6 жыл бұрын
Here is my opinion and it's just that, an opinion. I have been watching your vid's and you are trying to perform stol landings i see you always land front wheels then bring your tail down. I think if you can master the 3 point landing then you will have much more success making stol landings.
@AlexDiSessa
@AlexDiSessa 6 жыл бұрын
Maybe the videos shows more wheel landings. I also do 3 point without an issue.
@MrKswanny
@MrKswanny 6 жыл бұрын
As said, the wing controls the stalls not the tail. Gap seals are to help control elevator authority in the region of reverse command. Also, more so on slicker air framed airplanes, they help to reduce drag and pick up a little speed. Great video though! Keep up the good work I hope to meet up someday once my STi is airworthy.
@AlexDiSessa
@AlexDiSessa 6 жыл бұрын
kristopher swanson looking forward to it. Although I was not trying to stall less with the gap seal, I was just trying the stall speeds as reference, I could not see or feel any more control authority.
@billhamilton2366
@billhamilton2366 5 жыл бұрын
Hey the term is laminar flow... and less separation. Why are you making this video... This is common knowledge among people who know anything about their own aircraft except those who only have a pilots license. It's disturbing how little some pilots know about aerodynamics. The gap seal will simply provide less separation when the elevator is deflected with high angles.The lower surface of your horizontal stabilizer has lots of separation over the entire surface.
@Bushmasterpilot
@Bushmasterpilot 6 жыл бұрын
Everybody uses the same gay music...terrible.
@AlexDiSessa
@AlexDiSessa 6 жыл бұрын
yep!
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