vk3auu Posted August 23, 2007 Share Posted August 23, 2007 Just found this page about VG's. http://www.avweb.com/news/reviews/182564-1.html Happy slow flying, David Link to comment Share on other sites More sharing options...
Ultralights Posted August 23, 2007 Share Posted August 23, 2007 im not a fan of registering just to read 1 article. Link to comment Share on other sites More sharing options...
Bigglesworth Posted August 23, 2007 Share Posted August 23, 2007 Try Bugmenot and see if it is on there, I will check Link to comment Share on other sites More sharing options...
Bigglesworth Posted August 23, 2007 Share Posted August 23, 2007 Good old Bugmenot try name:[email protected] Password:password that'll get you in Link to comment Share on other sites More sharing options...
Guest Fred Bear Posted August 23, 2007 Share Posted August 23, 2007 Or more food for thought at: http://en.wikipedia.org/wiki/Vortex_generator Link to comment Share on other sites More sharing options...
Guest disperse Posted August 23, 2007 Share Posted August 23, 2007 ok so i read the article not throughly but what i get from it is PRO- decreases stall speed and low speed handling. CON- increases drag. you all know im not a flyer yet. but if we have aircraft with a stall below 45kts so i dont see the point....unless STOL is of a priority ....but i can see the mechanic's of why it works Link to comment Share on other sites More sharing options...
Guest Fred Bear Posted August 23, 2007 Share Posted August 23, 2007 Aah, you learn every single day mate. PROS and CONS all over the place in aircraft. Remember, one aircraft will always do what another cannot. ;) Link to comment Share on other sites More sharing options...
poteroo Posted August 24, 2007 Share Posted August 24, 2007 Read recently a response to installing all these STOL or SPEED kits which said: (1) Keep the engine tuned, the prop clean, and airframe rigged well (2) Polish the aircraft (3) Keep the weight down (4) Balance the load so that it flies at neutral trim......and you save lots of $$$$ happy days, Link to comment Share on other sites More sharing options...
vk3auu Posted August 25, 2007 Author Share Posted August 25, 2007 Actually the drag penalty in most aircraft is virtually nil. The lower approach and landing speed is always a bonus because if you can reduce the touch down speed by 10 percent, you will reduce brake and tyre wear by 21 percent. Also, if you put then on the rudder, you get a bit more rudder authority at slow speeds which comes in handy during cross wind landings after you get all the wheels on the ground, particularly in a real aeroplane/taildrager. David Link to comment Share on other sites More sharing options...
Guest Fred Bear Posted August 25, 2007 Share Posted August 25, 2007 particularly in a real aeroplane/taildrager. Oh come on Link to comment Share on other sites More sharing options...
poteroo Posted August 26, 2007 Share Posted August 26, 2007 Man after my own heart ! If only we could return to the 'good old days' of a huge paddock with all-over operations - then taildraggers would still be as popular, and as easy to teach ab initio in. happy days, Link to comment Share on other sites More sharing options...
Guest osprey5 Posted August 27, 2007 Share Posted August 27, 2007 Interesting stuff! So who's going to be first trying this on their Jabiru? Link to comment Share on other sites More sharing options...
Guest Fred Bear Posted August 27, 2007 Share Posted August 27, 2007 We have a young man at The Oaks who has the Jabiru SP with the vortex generators. Link to comment Share on other sites More sharing options...
Guest osprey5 Posted August 27, 2007 Share Posted August 27, 2007 Well that's a surprise - so we don't need to get Savanah's to land on shorter strips - any idea what his t/o and landing distances are? Link to comment Share on other sites More sharing options...
Guest Fred Bear Posted August 27, 2007 Share Posted August 27, 2007 I will find out for you. Dave C might have an idea too but somewhat reduced. Makes other characteristics totally out of the ordinary too. Stall speed etc. As I said, will find out some more. Link to comment Share on other sites More sharing options...
vk3auu Posted August 28, 2007 Author Share Posted August 28, 2007 Now we have to convince Rod Stiff to put them on as standard. Then we would have a good aeroplane. Might cost a bit extra for the certification though. They would go well on the little rudders of the early models too. Also, if you put them on the wings, you need to put them on the underneath side of the elevator to get more authority at the lower landing speeds. 1 Link to comment Share on other sites More sharing options...
Vev Posted December 11, 2008 Share Posted December 11, 2008 Hi … did any of you guys decide to fit VG’s to a Jab??? I spoke with a fellow in the US a couple of days ago that has fitted them to his SK and said that it made a huge difference to stall & manoeuvring speed including improved climb rates. He said that he has fitted them to both his wing as well as the underside of his tail so as to maintain elevator authority. He also said that his max speed has not really changed but may have dropped a 1 knot. I have to say there seems little down side … keen to hear views? Regards Jack Link to comment Share on other sites More sharing options...
facthunter Posted December 11, 2008 Share Posted December 11, 2008 VG's These have been around for a long time. They are used on the sides of the vertical stabiliser on the Boeing 727. I have seen an approved kit on a chieftain. The idea is to impart energy to the airflow close to the surface of the aerofoil and delay separation at high angles of attack and provide more lift at lower airspeeds, ie. make the wing work harder. They should be affixed somewhere near the leading edge, at a location BEFORE the airflow gets turbulent. The underside of the horizontal stabiliser would be the place to apply them regarding tailplane effectiveness, (NOT the elevator). Tapes or gap seals fitted to control surfaces assists effectiveness also. I would be surprised if there was much speed loss (if any) to most of the planes that we operate when these are fitted.. Nev. Link to comment Share on other sites More sharing options...
Yenn Posted December 12, 2008 Share Posted December 12, 2008 Have a look at Land Shorter! Home. There is a bit of info and they supply the VG.s at what they claim is a good price. I was toying with the idea of trying them on the Corby. We extended the strip about 300m and I can still not land before the old threshold, because of the upslope and some small trees. Link to comment Share on other sites More sharing options...
vk3auu Posted December 12, 2008 Author Share Posted December 12, 2008 Actually the underside of the elevator is the place to put them for maximum effectiveness. On my CH701 I have them placed right at the bottom when the elevator is at full up deflection. On the wing, the best place seems to be to place them right at the highest point when the angle of attack is about 15 degrees, which is where most wings usually stall. The earlier Jabs with their little rudders could probably also benefit from fitting them to the sides of the rudder, again at the extreme outside when at 15 degrees deflection. John Gilpin at Maleny is the bloke to get them from. David Link to comment Share on other sites More sharing options...
Vev Posted December 13, 2008 Share Posted December 13, 2008 Thanks for the responses everyone…. Greatly appreciated. I have been doing some reading on the net which mostly seems to concur with your feedback. I also spoke to Joa (designer and owner of Land Short in the US) following Ian’s suggestion to take a look at the web site. He was stating the best placement is to have the centre of the VG's at about 10% of the cord, which is about 100mm in from the leading edge for the wing on my J160. He said that some wings work best at 8% and others at 12% but 10% is about right for most. However he said to be mindful that one takes into account if you have swept back or forward wings as the cord length will be different to the actual wing itself, which is not an issue for my Jab. One the things I’m interested in is the potential to increase climb rate on my Jab 160, particularly of hot days. Most of the information seems to indicate that this is possible but I can’t seem to find a lot of documented support for this other than manufactures claims…. Any thoughts??? Cheers Jack Link to comment Share on other sites More sharing options...
Walter Klatt Posted December 13, 2008 Share Posted December 13, 2008 Landshorter VGs I use the Landshorter VGs on 2 of my airplanes. One is a Murphy Rebel amphib floatplane, and it has them at the 10 % chord position. Results were much better than expected. Stall was reduced by about 8 or 9 mph. This was at the recommended 10% chord position. Then I put them on my 912 Chinook, also an amphib floatplane, and for some reason, did not get anywhere near the same results. First, I tried them at the 10% chord position, but stall only reduced by about 1 or 2 mph at best. Then Joa told me to try them further forward, and that helped a little. I ended up at the 7 % chord position, but still only about 2 or 3 mph stall improvement. So it seems to depend a lot on the wing airfoil, I think. The Rebel has a modified 4415 wing, and not sure what the Chinook has, but it is thinner, and it is also a fabric wing vs the metal for the Rebel. No change in cruise speeds or any other handling or stalls with either plane using the VGs. Water take-offs on the Rebel are now faster, but they do require more power and/or technique change, as the VGs produce more drag at low airspeed and a higher angle of attack. I think climb is better, but that is hard to prove. Walter Link to comment Share on other sites More sharing options...
Vev Posted December 13, 2008 Share Posted December 13, 2008 Hi Walter… Many thanks for your input. It sounds like you must have stuck the VG’s on with some sort of double sided tape to try out the optimum position? If this is the case, what did you use and did you loose any of them in the process? Still keen to hear from someone with a Jab that has used VGs ??? Cheers Jack Link to comment Share on other sites More sharing options...
djpacro Posted December 13, 2008 Share Posted December 13, 2008 Stall was reduced by about 8 or 9 mph VG's can have a significant effect so I hope that some-one is looking at the effect on the design flight envelope eg http://www.recreationalflying.com/forum/general-discussion/18066-va-vso-vvvvvvvv.html Link to comment Share on other sites More sharing options...
geoffreywh Posted December 13, 2008 Share Posted December 13, 2008 I think that Aviation spruce have VG's for all types, Including Props! Apparently the first third of the prop gets to do some work. Very believable......If the dollar had not crashed then I would have tried some....I used VG's on A/2 Gliders since the early seventies I wouldn't build one without them!.... Link to comment Share on other sites More sharing options...
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