gbigs Posted February 23, 2016 Report Share Posted February 23, 2016 I'm sorry. I started this thread drift so if an admin wants to bundle it up and move it, might I suggest the topic header as "Flight Design vs. Pipistrel". When I do a google search wanting to read comparisons between aircraft X and aircraft Y, that is how I input the search, i.e. "Ch-701 vs Savannah". Search this site for both Flight Design and Pipistrel comparisons...they have been done before.... Also, you may want to consider that Flight Design has been dominating the SLSA market since it started. Hundreds of FD CTs are flying in the USA....a handful of Pipistrels are out there. Do you own an SLSA now? Have you flown either of these two aircraft? Do you know the difference between Rotax engines? Are you also comparing cabin dimensions, avionics suite, range, useful load, repair with experience in the product near you? Also remember that comparing Experimental status planes that are no longer meeting SLSA specs are not comparing apples to apples. In Europe and Canada the FD CT can be equipped with a double negative flap setting and a constant speed prop. They do not have the gross weight and speed restrictions as SLSA has in the USA. Link to comment Share on other sites More sharing options...
FlyingMonkey Posted February 23, 2016 Report Share Posted February 23, 2016 LOL that made me laugh. He actually did quote his source... "Aerodynamics For Naval Aviators, p. 71", if you're not going to read it, that's your problem! The ideal wing for flying would be one that is paper thin, long, and a short cord. If you can invent a mystery material that can achieve this and still have a lot of strength, you could also go fast and be maneuverable. The realistic wing for flying fast and maneuverable, is a low aspect ratio wing. This is due to material limitations. That said, a high aspect wing on the Pipistrel is not necessarily an indication of speed itself! That's why I specifically mentioned how thin it is too. Not at all...I did read it. But how does posting a snippet from a textbook supposed to tell me what point he's making? That's why I asked for clarification in my post about the effect of hacking wing length off of a given wing. I'm trying to understand the aerodynamics here; everything I have read tells me drag increases with lift, so a shorter wing of the same shape as a longer wing will have less drag and thus perform better at speed. But I guess I'm just too slow on the uptake to keep up with Eddie, so...whatever. Link to comment Share on other sites More sharing options...
deckofficer Posted February 23, 2016 Report Share Posted February 23, 2016 The proof is in the results of the NASA challenge. The 2008 event was entered by a local, about 15 miles from me. His Virus SW N2471P is registered Experimental-Glider. Entry fee is $3000, so his plane's performance will decide if this was just an expensive fly-in/event, or will he leave with some extra coin in his pocket. Overall Win paid him $50,000 The CAFE 400 Prize (speed and fuel consumption) paid $2000 Take off distance over 50 foot obstacle paid $3750 Angle of climb paid $3750 Cabin Noise (prize shared with Lambada) $1875 The Green prize (fuel consumption) title only Top speed title only The best climb rate task title only. $3000 to enter, $61,375 won, not a bad return considering going in they new the competition was going to be the light European Flight Design offering. FD did pick up $7500 in prize money and what was discussed earlier, $3750 of that amount was for lowest flyable speed. Kinda drives home the point Andy was making about the stall speed being fudged a bit on the Pip. Link to comment Share on other sites More sharing options...
Anticept Posted February 23, 2016 Report Share Posted February 23, 2016 Not at all...I did read it. But how does posting a snippet from a textbook supposed to tell me what point he's making? That's why I asked for clarification in my post about the effect of hacking wing length off of a given wing. I'm trying to understand the aerodynamics here; everything I have read tells me drag increases with lift, so a shorter wing of the same shape as a longer wing will have less drag and thus perform better at speed. But I guess I'm just too slow on the uptake to keep up with Eddie, so...whatever. Oh, I see. The issue of lift vs drag is much more complicated than that. Your argument holds up when we're talking about a single wing, but it breaks down when we change the shape. Wide wingspan, short chord wings reduce the development of wingtip vortices, for one. Reducing the thickness of the wing reduces form drag. More lift means lower angle of attack, so there's another benefit as this also reduces form drag. A tapered wing design also reduces wingtip vortice formation. The whole thing is an engineering can of worms... one that is a pain in the ass to explain in a few short paragraphs! I will say one additional thing though, that I didn't mention before: the Pipistral wings look a bit more fragile than FD's wings. Not going to matter in normal flight, but having long skinny wings is a disadvantage in turbulence! Link to comment Share on other sites More sharing options...
deckofficer Posted February 24, 2016 Report Share Posted February 24, 2016 100Hamburger, I believe the main reason for the numbers here in the States being so lopsided, is Slovenia doesn't have reciprocal agreements with the USA for aircraft certification. Very recently, Pipistrel which is located near the border of Italy, opened a facility there for the assembly of the LSA version and Italy has the agreements in place with the US. IMHO, had Pipistrel been able to enter the US LSA market at the same time as FD, a lot of the forum members would be flying the Virus SW LSA. Link to comment Share on other sites More sharing options...
deckofficer Posted February 24, 2016 Report Share Posted February 24, 2016 I will say one additional thing though, that I didn't mention before: the Pipistral wings look a bit more fragile than FD's wings. Not going to matter in normal flight, but having long skinny wings is a disadvantage in turbulence! Not in this case, remember the Virus SW has a Vb of 130 kts. That is a lot of green arc. Link to comment Share on other sites More sharing options...
Anticept Posted February 24, 2016 Report Share Posted February 24, 2016 Not in this case, remember the Virus SW has a Vb of 130 kts. That is a lot of green arc. Not what I meant. I meant they look a bit more fragile from a bending moment perspective. There's specifically a warning in the Pipistrel POH about the max maneuvering speed, and how doing full deflection in certain maneuvers can still damage the wing. Flight Design has done testing up to 180 knots, as well as testing over 6 Gs, and called it good. I don't think they've ever tried to actually break the wing. The weak point on an FD is the tail stabilator. Link to comment Share on other sites More sharing options...
FlyingMonkey Posted February 24, 2016 Report Share Posted February 24, 2016 Corey, I agree once you change the shape the game gets WAY more complicated. I was just trying to keep it simple with the apples to apples comparison of a single wing shape of variable length. I was just stating the general case, because no definitive statement can be made between wings of varying shape. I was getting frustrated because I made this point a few times and nobody addressed it. There are a lot of aerodynamic tricks out there too. When they shortened the CT2k to make the CTSW, Flight Design added a more stall-resistant droop wingtip to minimize the stall speed gain. But I'm sure the speed advantage of the shorter wing was slightly offset by the extra drag of the droop tips. Overall I think it was a successful design change...a knot or two faster stall and a few knots more speed. Plus a look and feel more in line with what the US market likes -- we don't tend to like motor gliders as much as the Europeans do. Link to comment Share on other sites More sharing options...
Ed Cesnalis Posted February 24, 2016 Report Share Posted February 24, 2016 ... everything I have read tells me drag increases with lift, so a shorter wing of the same shape as a longer wing will have less drag and thus perform better at speed. Your lift requirement in cruise is equal to your weight. If you cut your wing in half you would cut your lift in half or better. So your new half wings wouldn't work with the same motor. Cutting drag isn't the whole picture. Your half wing with as you say the same profile needs to make up a big lift deficit, how? Whatever solution you chose will cost drag. Link to comment Share on other sites More sharing options...
FlyingMonkey Posted February 24, 2016 Report Share Posted February 24, 2016 Your lift requirement in cruise is equal to your weight. If you cut your wing in half you would cut your lift in half or better. So your new half wings wouldn't work with the same motor. Cutting drag isn't the whole picture. Your half wing with as you say the same profile needs to make up a big lift deficit, how? Whatever solution you chose will cost drag. Yeah, but I'm not talking about half, I'm talking maybe 10%. The airplane would have to fly at higher angle of attack, which will cost a little drag, but the drag reduction from the wing would more than offset it, IMO. After all, that is exactly how the CTSW was born. Link to comment Share on other sites More sharing options...
jackwhickman Posted February 24, 2016 Report Share Posted February 24, 2016 To return to the original topic. Is FD still issuing LOA's, and if they go belly up, where does CTSW flight, maintenance, modifications etc. guidance come from? Do we all go Experimental? Link to comment Share on other sites More sharing options...
Anticept Posted February 24, 2016 Report Share Posted February 24, 2016 To return to the original topic. Is FD still issuing LOA's, and if they go belly up, where does CTSW flight, maintenance, modifications etc. guidance come from? Do we all go Experimental? I spoke with AFS 610 on this subject. They stated that if a type manufacturer goes belly up, then someone has to take responsibility for ongoing airworthiness, and that a new owner would need to provide proof to rights to the designs, manufacturing data, and if any new parts and airframes are to be built, compliance with appropriate consensus standards. It's really NOT in the interest of an aviation company to be tight fisted about this data. I highly suspect that in such a case, it's give up the data or face some serious lawsuits since many regulations around the world require the manufacturer to provide ongoing support, and this includes many countries in Europe as covered by EASA. Going E-LSA would eliminate any reliance on the manufacturer here in the US. Not sure about abroad. Link to comment Share on other sites More sharing options...
jackwhickman Posted February 24, 2016 Report Share Posted February 24, 2016 Corey Not sure what they mean "Someone has to take responsibility for ongoing airworthiness" ----- or what? I suppose we just hope FD or some new owner will always be there These are interesting times. Link to comment Share on other sites More sharing options...
Anticept Posted February 24, 2016 Report Share Posted February 24, 2016 It means engineering for repairs and any other required compliance. We, in the field, can't write our own repairs. But, someone has to. Link to comment Share on other sites More sharing options...
N456TS Posted February 24, 2016 Report Share Posted February 24, 2016 Not sure what they mean "Someone has to take responsibility for ongoing airworthiness" ----- or what? I suppose we just hope FD or some new owner will always be there If they went out of business and no one bought them out to continue fleet support, then the FAA will require all the FD S-LSAs to be converted to E-LSAs at the owner's expense. It won't happen, as there is too much value in continuing operations/business. Link to comment Share on other sites More sharing options...
FlyingMonkey Posted February 24, 2016 Report Share Posted February 24, 2016 I spoke with AFS 610 on this subject. They stated that someone has to take responsibility for ongoing airworthiness, and that a new owner would need to provide proof to rights to the designs, manufacturing data, and if any new parts and airframes are to be built, compliance with appropriate consensus standards. It's really NOT in the interest of an aviation company to be tight fisted about this data. I highly suspect that in such a case, it's give up the data or face some serious lawsuits since many regulations around the world require the manufacturer to provide ongoing support, and this includes many countries in Europe as covered by EASA. Going E-LSA would eliminate any reliance on the manufacturer here in the US. Not sure about abroad. The AeroJones license agreement might include these rights, especially if FD Gmbh is going to go away or just become and administrative company. I'd love to see Tom and FD USA pick this up for the USA market, but I have no idea what would be involved for them or if it's even something they would want to do. I bet the legal compliance costs are high and the returns modest. Link to comment Share on other sites More sharing options...
Cluemeister Posted February 24, 2016 Report Share Posted February 24, 2016 Does anyone have any idea how long the courts will take to sort this out? Link to comment Share on other sites More sharing options...
FastEddieB Posted February 24, 2016 Report Share Posted February 24, 2016 If they went out of business and no one bought them out to continue fleet support, then the FAA will require all the FD S-LSAs to be converted to E-LSAs at the owner's expense. If it were to happen, for most it would be a relatively painless transition, costing right around $300 and providing lots of benefits. Mainly affected would be those either renting out CT's, those using them for instruction, or those wishing to rent them. Beyond those, very little downside*, and lots of upside. *I think someone (Andy?) said financing an Experimental is more difficult. Link to comment Share on other sites More sharing options...
Roger Lee Posted February 24, 2016 Report Share Posted February 24, 2016 You guys are rumor milling. It sparks unrest and could hurt the sales of the very people you want to do well to support your plane. The more outsiders read your rumors the more they will stay away. Rumors kill companies. Best to let the truth finish sorting out. Link to comment Share on other sites More sharing options...
Flight Design USA Posted February 24, 2016 Report Share Posted February 24, 2016 Gentlemen, the engineering side of Flight Design GmbH. is intact and functioning. AeroJones Aviation has funded that part of the operation currently through the administrator and they need it to be intact and functioning for their approvals with the CAAC and the FAA where we are now planning to deliver airplanes from AJA. The combination of the functioning engineering side and our being here for administering the COSM under a Workshare Agreement are in compliance with the FAA requirements. Link to comment Share on other sites More sharing options...
Roger Lee Posted February 24, 2016 Report Share Posted February 24, 2016 If guys don't have any facts then it's probably best left unsaid. This type of rumoring isn't any different than when your neighbors see you walking with your grandchild and then start a neighborhood rumor mill saying you're a child molester. The damage gets don't without a ounce of truth and there is rarely any recovery. Link to comment Share on other sites More sharing options...
FlyingMonkey Posted February 24, 2016 Report Share Posted February 24, 2016 Gentlemen, the engineering side of Flight Design GmbH. is intact and functioning. AeroJones Aviation has funded that part of the operation currently through the administrator and they need it to be intact and functioning for their approvals with the CAAC and the FAA where we are now planning to deliver airplanes from AJA. The combination of the functioning engineering side and our being here for administering the COSM under a Workshare Agreement are in compliance with the FAA requirements. Outstanding, thanks! Link to comment Share on other sites More sharing options...
ralarcon Posted February 24, 2016 Report Share Posted February 24, 2016 Gentlemen, the engineering side of Flight Design GmbH. is intact and functioning. AeroJones Aviation has funded that part of the operation currently through the administrator and they need it to be intact and functioning for their approvals with the CAAC and the FAA where we are now planning to deliver airplanes from AJA. The combination of the functioning engineering side and our being here for administering the COSM under a Workshare Agreement are in compliance with the FAA requirements. Thanks for that clarification. Cheers Link to comment Share on other sites More sharing options...
Ian Posted February 24, 2016 Report Share Posted February 24, 2016 Seems that the European authorities are on the case too http://www.flyer.co.uk/easa-reconsiders-policy-orphan-aircraft/ Link to comment Share on other sites More sharing options...
FlyingMonkey Posted February 24, 2016 Report Share Posted February 24, 2016 Ian, can you explain to we in the US the difference between an "EASA permit to fly" and a regular type certificate? And the difference between EASA and LAA? Link to comment Share on other sites More sharing options...
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