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Post by maddog on Jan 8, 2012 12:47:56 GMT -5
wafer, Also note that the Sonex is not recommended for sod fields and tri-gear... And probably not the 601XLB that I am learning to fly in... Already had to do the "upgrade" to the nose gear on the 601 three years after its first flight. (plane is based on grass field that wishes that it was level and straight) Just saying that I am trying to bend the grass before I actually land. Anyway, thanks for the heads up, but I will be a watching for any and all problems. Still kicking around the idea of the Riblett airfoil , just haven't done enough research yet to see if this is the way to go.. Any heads up on the Riblett airfoil good, bad, and ugly would be helpful. I am not trying to bastardize the Sonerai, but it has gone from the pylon racer to a pylon trainer to a cross country and then an extended cross country aircraft. Why not try to make it the best ("fastest" LSA two place) available? Mike
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Post by n3480h on Jan 8, 2012 14:11:09 GMT -5
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Post by o2koold on Jan 8, 2012 20:30:18 GMT -5
Jon or Mike, If you are interested in considering other airfoils, in particular to meet LSA, send me a PM to my user name @ msn.com. I have a couple of word documents based on a discourse I had with a friend the likes to design and play with aerodynamic possibilities. If I were to start over and desired to keep it in LSA requirements, I would not use this airfoil. There are better that will lower the stall, only by a little, but offer a better ROC. The trade off is that their drag is higher when going over the 140 mph mark. The plans airfoil is great if your plan is to go all out at 160 MPH, like the SI.
As a side note, my plan is to try my hardest to keep mine as LSA. Most important is build it light. That means to the plans. I have not added to them. I have also spent a considerable amount of money to keep it light at every place I could. I will be stating the gross as 1000 or 1050 LBS (I am building a IIL). I will keep it as clean as I can for parasite drag, only to trade some of this for the required down reflex on both ailerons. I will start at just over the 1/4" the plans call for and play with this to see if I can get the 51 mph for stall. The Vh speed is easy, regardless of who is piloting, any placard must be adhered to. So limiting the max continuous RPM to 138 mph will do the trick. This will also let you legally use the extra on climb out. Scott R
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4trade
Junior Member
Posts: 51
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Post by 4trade on Jan 9, 2012 11:48:08 GMT -5
If you want to chance airfoil and achieve LSA stall speed, there is very little choices to go. 1000 lbs gross you need (coefficient lift) Cl 1.79 and 1150 lbs gross Cl 2.06....that mean only two or three airfoil to choose and those ones must use under 1000 lbs gross. GAW 2 have Cl 2.04.......and LS (1)-0413 have Cl 2.07......so in a 3 D wing those will be Cl 1.73 max....Without bigger wing area or flaps choices is basically those two and less than 1000 lbs gross. Check out that Finnish Sonerai 1...this one have GAW airfoil and Sonerai 2 wing with flaperons: www.sonerai.proboards.com/index.cgi?board=airframe&action=display&thread=95...and remember that those both airfoil have 2.5 times bigger pitching moment, so CG limits must be calculate again and changed smaller or tail area must build bigger if used original CG limits
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Post by paul57 on Jan 10, 2012 16:48:43 GMT -5
So if I placard my IILT to not exceed 138 mph, and I get the stall speed to 52 mph or lower I can just say its a LSA and fly with no medical? Is there any "official" paperwork that must be done?
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Post by bil438 on Jan 11, 2012 4:49:32 GMT -5
My SIILS has an empty weight of 533 lbs, with a Jabiru 2200a engine. My weight at takeoff with 16 gals fuel and 260 lb pilot is about 990 lbs. I did a series of stall tests and airspeed checks at landing and takeoff. The stall is 63 +/- 1 mph. The vortex generators might reduce the stall by 5mph. I can't see how you'd get stall down to LSA. Bill
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4trade
Junior Member
Posts: 51
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Post by 4trade on Jan 11, 2012 8:50:37 GMT -5
I don´t think that VG will help very much. VG will probably help keep that airflow little longer in a wing, so it will add little more AoA, but that don´t mean automatically higher lift coefficient.
Sonerai 12 % airfoil stall at 14 deg AoA, and same airfoil family 64A215 (15 % thick) stall 16 degree AoA. That 15% airfoil have more radius at LE, so it will have bigger AoA angle, but not more Cl.
These airfoil´s have small LE radius, and it will keep AoA small, so there is almost no benefit for VG. VG is not some "miracle lift devise" for this kind of airfoil. It will work better with bigger LE radius airfoil.
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Post by paul57 on Jan 11, 2012 11:40:24 GMT -5
I'm not an engineer, but will the shape of the fuselage add any lift? My stall speed is somewhere below 60 mph already, and I plan on reducing weight in both the pilot and plane. I,m just wondering if its worth it just to avoid a medical. (please see my previous post)
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Post by o2koold on Jan 11, 2012 11:55:53 GMT -5
Hi Paul, Since your planes is done and flying, what does the POH state for your Vs and Vh, if listed on the Vh. If it has ever operated above 51mph for Vs and 138 mph for Vh, Then yours can not ever be operated as LSA. If the manufacture records these numbers within the limit, then no paper work would be needed. But the plane is not allow to operate above them. If it get recorded in the logs as above, that sets it up to be ineligible as LSA. Just like when you upgrage a J3 to a bigger engine and allow a greater gross (greater than LSA limit of 1320lb), that J3 can not go backward to the lighter gross. I hope this helps. Scott R
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Post by paul57 on Jan 11, 2012 20:23:18 GMT -5
Plane is not "done". I don't think it can ever be done. So no POH yet.
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peterzabriskie
Junior Member
"Did I make that part the best I possibly could have?" Unknown
Posts: 99
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Post by peterzabriskie on Jan 13, 2012 8:54:38 GMT -5
So for those of us who joined Jeff for his Hoerner wingtip demonstration do you think that the small amount of change these bring will lower stall speed? Secondly the article referred to at the top of this thread about Rog Godfrey's Sonerai and his riblet wing, he also extended the length of the wings which as I am reading here the larger wing area may lower the stall speed? -Pete
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4trade
Junior Member
Posts: 51
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Post by 4trade on Jan 13, 2012 11:27:51 GMT -5
Hoerner tip´s should affect little, but not even close enough. Riblet airfoil will need lot of wing area more, to drop stall under LSA rules. Sonerai airfoil Cl is approx 1.5.....RV 3 airfoil (NACA 23012) Cl is approx 1.6 at those stall speed area. RV 3 have 50% of span flaps, better airfoil for lift, 6 sq/feet bigger wing and 51 mph stall speed at 1050 LBS (Vans give stall speed at solo weight). We all know that Van´s numbers are true. www.vansaircraft.com/public/rv-3per.htmSo, even with RV´s bigger wing and flaps, Sonerai should be at 1050 lbs gross to achieve LSA stall. There you go...build it with RV 3 or Sonex wing and keep it light....and you have LSA plane
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peterzabriskie
Junior Member
"Did I make that part the best I possibly could have?" Unknown
Posts: 99
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Post by peterzabriskie on Jan 13, 2012 16:29:55 GMT -5
Hoerner tip´s should affect little, but not even close enough. Riblet airfoil will need lot of wing area more, to drop stall under LSA rules. Sonerai airfoil Cl is approx 1.5.....RV 3 airfoil (NACA 23012) Cl is approx 1.6 at those stall speed area. RV 3 have 50% of span flaps, better airfoil for lift, 6 sq/feet bigger wing and 51 mph stall speed at 1050 LBS (Vans give stall speed at solo weight). We all know that Van´s numbers are true. www.vansaircraft.com/public/rv-3per.htmSo, even with RV´s bigger wing and flaps, Sonerai should be at 1050 lbs gross to achieve LSA stall. There you go...build it with RV 3 or Sonex wing and keep it light....and you have LSA plane Copying your 6sq/ft bigger wing idea Rog Godfrey did this with his Sonerai. "...took my new friend’s advice and built a set of replacement wings with a Riblett 35A415 airfoil. Built much like the original, it’s about two inches thicker at the spar. The spar C-channel is (obviously) two inches taller, and the cap strips are built substantially longer to accommodate the additional 4-foot span." "The plane cruises at about the same speed, climbs much better, and lands much slower. It won’t stall power off but just mushes along like an old Cherokee."(Roger Godfrey) It seems 4trade that you are sold on Rv;s and their performance, but I think the Sonerai folks are working towards a Sonerai performance they can live with. I know lqbanotxano flies and Riblet airfoil Sonerai in Texas and we did not hear from him here about his results. I am not wanting to antagonize 4trade but I can't help but believe that with the proper combination the desired results can't be achieved without going to another plane like the RV or Sonex. John Monnett made the original Sonerai to race formula-Vee 1600cc VW engine powered planes, as I understand the history. Then the plane was "stretched" so two folks would fit. The wing was then re-enforced for strength and it gave the Sonerai basic aerobatic capabilities. If the mission of the plane was focused away from racing and aerobatics and towards a single or two place "around the patch"/ economy crosscounty and the wings designed with more area and utilize the full span ailerons as flaperons I am not seeing a huge hurdle to jump here, aside from the cost to build and sandbag a set of wings to confirm necessary strength. Something any small group of interested people could accomplish. -Pete
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hans
Full Member
Posts: 166
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Post by hans on Jan 13, 2012 18:20:51 GMT -5
So for those of us who joined Jeff for his Hoerner wingtip demonstration do you think that the small amount of change these bring will lower stall speed? Secondly the article referred to at the top of this thread about Rog Godfrey's Sonerai and his riblet wing, he also extended the length of the wings which as I am reading here the larger wing area may lower the stall speed? -Pete Yes, I do expect Hoerner tips to work at slow speeds. They push the wing tip vortex further to the outside, hence create a higher effective span. This reduces spanload, which in turn should reduce stall speed. In addition to this, I would also expect better aileron response at slow speeds, but likely this is something Jeff should comment on. Also, it would be interesting to learn whether these tips loose anything on fast end of the envelope... Hans
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4trade
Junior Member
Posts: 51
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Post by 4trade on Jan 14, 2012 6:59:32 GMT -5
Hoerner tip´s should affect little, but not even close enough. Riblet airfoil will need lot of wing area more, to drop stall under LSA rules. Sonerai airfoil Cl is approx 1.5.....RV 3 airfoil (NACA 23012) Cl is approx 1.6 at those stall speed area. RV 3 have 50% of span flaps, better airfoil for lift, 6 sq/feet bigger wing and 51 mph stall speed at 1050 LBS (Vans give stall speed at solo weight). We all know that Van´s numbers are true. www.vansaircraft.com/public/rv-3per.htmSo, even with RV´s bigger wing and flaps, Sonerai should be at 1050 lbs gross to achieve LSA stall. There you go...build it with RV 3 or Sonex wing and keep it light....and you have LSA plane Copying your 6sq/ft bigger wing idea Rog Godfrey did this with his Sonerai. "...took my new friend’s advice and built a set of replacement wings with a Riblett 35A415 airfoil. Built much like the original, it’s about two inches thicker at the spar. The spar C-channel is (obviously) two inches taller, and the cap strips are built substantially longer to accommodate the additional 4-foot span." "The plane cruises at about the same speed, climbs much better, and lands much slower. It won’t stall power off but just mushes along like an old Cherokee."(Roger Godfrey) It seems 4trade that you are sold on Rv;s and their performance, but I think the Sonerai folks are working towards a Sonerai performance they can live with. I know lqbanotxano flies and Riblet airfoil Sonerai in Texas and we did not hear from him here about his results. I am not wanting to antagonize 4trade but I can't help but believe that with the proper combination the desired results can't be achieved without going to another plane like the RV or Sonex. John Monnett made the original Sonerai to race formula-Vee 1600cc VW engine powered planes, as I understand the history. Then the plane was "stretched" so two folks would fit. The wing was then re-enforced for strength and it gave the Sonerai basic aerobatic capabilities. If the mission of the plane was focused away from racing and aerobatics and towards a single or two place "around the patch"/ economy crosscounty and the wings designed with more area and utilize the full span ailerons as flaperons I am not seeing a huge hurdle to jump here, aside from the cost to build and sandbag a set of wings to confirm necessary strength. Something any small group of interested people could accomplish. -Pete Pete, i am not "sold" for anything. I am just telling here what it takes to convert Sonerai to LSA plane, and i am only telling here it for aerodynamic point of view. My purpose is just "lighten" that subject, because overall in this subject is lot of believes and guesses that not based on a aerodynamics. Example: Somebody want to use Riblett GA35-415 airfoil, and achieve LSA stall speed.....few sq/feet don´t mean nothing....you need minimum wing area 107 sq/feet to achieve that LSA stall at 1100 lbs gross. Original airfoil you need 130 sq/ feet wing at 1100 lbs gross. I am just saying that it is almost impossible without flaps, or huge wing area...as we know, Sonerai 2 have only 84 sq/feet wing area.....so you need 55 % bigger wing area without flaps if you build LSA wing and want to use original airfoil. So, if you build three Sonerai wing panel and "glue" it to one big wing, it is not enough even that big wing.....do you get the point how far that LSA stall is? There is some other claims too, that is not true...like somebody claims that Riblett airfoil don´t affect cruise (or top) speed. Absolutely nonsense. This airfoil have 60% more drag than original airfoil. Aerodynamic science is right, not somebody´s empirical claims. You say that i am sold for RV performance, it is not true. If somebody use RV wing or airfoil in Sonerai, it will reduce performance of Sonerai, because of bigger wing area and bigger drag of airfoil. That is more like lack of performance compare to original plane.... I am all about performance, aerobatics and race! So, don´t shoot the messenger..... I am building Cassutt now. Plane is here: www.cassutt-racer.com/forums/viewtopic.php?f=16&t=42&sid=658a115da44ea004fbedc6111a6953cf
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