|
|
Post by kraigrinker on Dec 17, 2011 13:22:50 GMT -5
I have a sonerai 11 s with a A-75, flys great but I am out of a short strip with trees etc and think I would like to look at the idea of flapperons. Does anyone know the flying characteristics, stall speed reductions (approx.)and where I can get a hold of drawings to do so? Is it worth it? Any info would be very helpful, my aircraft is the low wing. Thanks.
|
|
hans
Full Member
Posts: 166
|
Post by hans on Dec 17, 2011 14:39:12 GMT -5
Hi, first of all welcome to this community and congratulations on your purchase. Check out this thread: www.sonerai.proboards.com/index.cgi?board=airframe&action=display&thread=95 for some more information about flaperons. Please note that those that confirm a lower stall speed and better climb rates use a wing with a modified wing section. Those that kept using the original wing section only report a slightly better visibility over the nose during approach/final, but other than that no real improvements. cheers Hans |
|
|
|
Post by kraigrinker on Dec 17, 2011 20:06:25 GMT -5
I wonder what a good set vgs would do on a sonerai two, a lot of people clain wonderful results on other clean aircraft such as rvs and so on. Has anyone had any experience with them on a sonerai?
|
|
|
|
Post by mayday on Dec 17, 2011 20:34:44 GMT -5
Wouldnt flaperons with full length ailerons be a bad idea? I wonder what a stall is like with full length flapperons down, wouldnt the entire wing stall at about the same time possibly putting you at risk of entering a spin? But then again the same thing would happen with full length ailerons either way.
|
|
hans
Full Member
Posts: 166
|
Post by hans on Dec 18, 2011 5:33:32 GMT -5
Wouldnt flaperons with full length ailerons be a bad idea? I wonder what a stall is like with full length flapperons down, wouldnt the entire wing stall at about the same time possibly putting you at risk of entering a spin? But then again the same thing would happen with full length ailerons either way. it's a property of rectangular non-twisted wing planforms (like that of a Sonerai) to stall at the root first, so spin entry risks shouldn't be all that much different. What really is different though, is that by deploying the flaperon you increase the wing section pitching moment, so the elevator/stabilizer need to work harder to keep equilibrium. Especially with a center of gravity far forward you might end up with a lack of pitch control in the low speed range... cheers Hans |
|
hans
Full Member
Posts: 166
|
Post by hans on Dec 18, 2011 5:43:57 GMT -5
I wonder what a good set vgs would do on a sonerai two, a lot of people clain wonderful results on other clean aircraft such as rvs and so on. Has anyone had any experience with them on a sonerai? that's an interesting question - has anyone ever used vortex generators on a Sonerai wing? cheers Hans |
|
|
|
Post by mayday on Dec 18, 2011 6:08:15 GMT -5
Wouldnt flaperons with full length ailerons be a bad idea? I wonder what a stall is like with full length flapperons down, wouldnt the entire wing stall at about the same time possibly putting you at risk of entering a spin? But then again the same thing would happen with full length ailerons either way. it's a property of rectangular non-twisted wing planforms (like that of a Sonerai) to stall at the root first, so spin entry risks shouldn't be all that much different. What really is different though, is that by deploying the flaperon you increase the wing section pitching moment, so the elevator/stabilizer need to work harder to keep equilibrium. Especially with a center of gravity far forward you might end up with a lack of pitch control in the low speed range... cheers Hans That is a good point, so if building a Sonerai, the tail surface sizes should be increases proportionately? Is there a Calculator somewhere, for figuring out surface area? |
|
hans
Full Member
Posts: 166
|
Post by hans on Dec 18, 2011 8:29:24 GMT -5
it's a property of rectangular non-twisted wing planforms (like that of a Sonerai) to stall at the root first, so spin entry risks shouldn't be all that much different. What really is different though, is that by deploying the flaperon you increase the wing section pitching moment, so the elevator/stabilizer need to work harder to keep equilibrium. Especially with a center of gravity far forward you might end up with a lack of pitch control in the low speed range... cheers Hans That is a good point, so if building a Sonerai, the tail surface sizes should be increases proportionately? Is there a Calculator somewhere, for figuring out surface area? I was not implying that anything needs to be increased (perhaps the current surfaces are big enough to cope with this modifiction), but since a flaperon constitutes a design change, this is one item I would verifiy before embarking on it... Another item to verify would be the flaperon- and control attachements: deploying the flaperons would increase camber, hence put a higher load on the aft part of the section. You'd need to verify that the current attachement would still be within the design envelope with this higher aft loading... Then there is yet an additional load case to consider: deployed flaperons and a high-G pull-up just below V(a). Since you have effectively increased the maximum Cl your wing can produce (which was what you set out to achieve in order to be able to fly slower), it will go into an accellerated stall at higher G-loads, i.e. it will put a higher load into your wingspar/wing attachement. There's a number of ways to cope with this extra load, the easiest of which would be to placard your plane for a lower V(a) when the flaperon is deployed. This would then be your Vfe (max. flap extension speed), well below the normal V(a). A derivative of this previous load case would be an assymetric one: flaporon deployed, high-G pull-up whilst turning into a bank. For obvious reasons, don't forget to analyse this one too... To paraphrase Bob Hoover: "when changing a design, YOU're the engineer in charge..."  Hans |
|
|
|
Post by raceair on Dec 18, 2011 8:38:49 GMT -5
I have no experience with Flaps, or Flaperons, on a Sonerai......BUT...I do know that flaps on a Cassutt Racer are a no-no.....I have direct experience with that. The Flaps on a Cassutt totally change the airflow over the Stabilizer/elevator, and the 'feel' and effectiveness in the flare are almost non-existant.
Before I would put Flaps or Flaperons on a Sonerai, I would add a small Belly flap, near the Center of Pressure, to help slow the approach speed while coming in high and pointing at the runway.....
Side note....I will be away from computers for several days, so cannot respond with any more comments.......Ed
|
|
|
|
Post by n3480h on Dec 18, 2011 9:13:38 GMT -5
Fire up your chain saw and cut the trees down. ;D
Tom
|
|
