# New Ultralight and LSA Trainer design PAIR 2

Discussion in 'Aircraft Design / Aerodynamics / New Technology' started by Rienk, Aug 21, 2010.

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1. Aug 23, 2013

### Rienk

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I'm not sure I know what your asking, or I didn't explain things fully?
I was referring to just the wingskin parts (top and bottom), which excludes the spars and some ribs. All these parts are bonded together like a typical all-composite aircraft.
We are not going for the lightest structure, but for the lowest cost balanced with the simplest to manufacture (at least according to our abilities).

(and a reminder, I am NOT an aero engineer, so I have to rely on others)

2. Aug 23, 2013

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Torsion from your wing with a single spar will be reacted almost entirely by the skin. That results in significant shear in the wing skin. Any break in the skin (your LE/TE joint) will need to "hand over" that shear, or your wing will simply fail in torsion.

3. Aug 23, 2013

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I know, I don't get it either, what you say does certainly seem sort of logical but in reality a two seater takes four times as long to build as a single seater, I don't know why but everyone I know who has built both has had the same experience as me in that regard. The reason I said 'sort of logical' is that the task must expand at some point mustn't it? I mean a fifty seater is a bigger job than a single seater isn't it? Would you say it is only fifty times as big a job as a single seater? If I can build a single seater alone in two months does that mean I can build a fifty seater alone in 8 years?

Idon't know the answer except from real experience, double the seats =four times the work but probably only double the cost ...

No - the same story, I was referring to personal experience building ultralights and the last time I built one our Australian 95.10 category was exactly the same as FAR23 Pt103. Here are some quick scans from Berger-Burr's "Ultralight and Microlight Aircraft of the World"2nd Edition 1985, nearly 20yrs before our weight limit was increased.You can see the weights of these if the print is large enough, most are around 220lbs EW. That's just a few, there are dozens in the book,amateur designer/builders in Oz back then really picked up the ball and ran with it - I wish that was the case these days ...

After the book scans I have added a couple of other pics I've rescued of planes I built that were also under 254lbs EW and with less than 4lb/ft^2 wing loading, so they were fully legal. The first shows the welded (nickel-bronzed actually) CRMO fuselage of a Christen Eagle looka-like that I called the Macrobat and a single seat cub-alike I called the Mach 0 (Mach zero, although some folks thought it was Macho,and it wasn't very macho at all ...great fun plane though) - all my planes were named Mac-something, MAC is my initials. Somewhere I have pics of the very first I built which was a Heath Bullet (very roughly speaking) which I called the Machine.

litespeed and Topaz like this.
4. Aug 23, 2013

### Rienk

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First of all, we are using a full double spar (from tip to tip) both with CF caps and FG webs.
Also, the front joint is actually under the wing, almost at the 25% chord (spar) location. The entire D section is part of the top skin.
I don't think we'll be having problems.

5. Aug 23, 2013

### Rienk

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He "says" the plans are essentially done in French, and that English is only a few weeks more. I'm not holding my breath, and am not in a hurry.

You are right about the training option.
My thought is that it would be nice to have a super basic UL that people could get into with almost no training. A plane that climbs and decends based on throttle, with only a rudder for control, would be very easy to fly, and allow for a novice to get in the air quickly (though I assume cross-winds are an issue?).
Of course, I would expect that many people would quickly want to move on to a more challenging and fun UL, which is what we are discussing in this thread. I see the Spratt103 as a loss leader to inexpensive flight, to get people hooked. Nonetheless, prospective pilots can always jump right into the standard UL if they so desire.
For example, a standard UL pilot could take a friend, and they can go flying together, if the friend starts with the simple Spratt?
Good gateway drug?

6. Aug 23, 2013

### Dana

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There is, more or less... a PPG or PPC. PPC is fairly sedate, but many are satisfied with that, others move on. PPG, otoh, can be as wild and crazy (and challenging) as you want it to be, but the speed and range are limiting... many ppgers add another form of flying but keep flying PPG too.

Dana

7. Aug 23, 2013

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All the people I know off have vastly different experiences. Well, many have the same experience, but in all cases I've seen that's due to complexity. A nosedragger, electric flaps, RG, EFIS vs basic 4 and an endless list of other "improvements" vastly increase the amount of work. Apples to apples, like the earlier list of comparable designs, I don't see that trend at all. Can you really build an RV8 in a quarter of the time of an RV10 (so 375-500 hours)? Can you really build a Sonerai in 1/16th of the time of a Bearhawk (120 hours then)?
Same for pretty much any production plane (where the majority of the cost is labor), the increase for a bigger/heavier plane is modest if you keep the complexity the same.
Sure, the amount of work increases, but less than linear. Otherwise scaling up wouldn't make sense and we would all be flying VLJ's, not A380's and we would have single-seat, certified production aircraft that were 1/16th of the price of a C172, so 15K...
Any of those who were fully load-tested? Some look impossibly thin for the (still sizeable) loads. Putting 3 me's on the stab is still short of ultimate load for most UL's in that category.

I hope I don't sound pedantic, but I've seen designs where hundreds of that design had been flying for a decade or more. Still plenty of parts that were not even strong enough for limit load and thus the majority never succeeded in certification in one of the local regulatory schemes here. Not having the legal obligation to do a full-blown investigation (NTSB) helps a lot, plenty of lethal crashes that never even got looked into, including many that were clearly structural.
Any joint that can't "transfer" the shear will break the D-section since it's the whole element that takes the torsion. Take a beer can, cut it vertical and try twisting it. Seriously, leave these kind of issues to somebody who has the skill and understanding. Belief or thinking has no place in aviation.

As for the "cheap" UL... well. All of that has been tried. Still expensive to make, harder to pilot and few buyers in the end. A talk to some actual manufacturers is sobering enough. If you find any that can sell a powered trike for less than 15K without a loss, let me know. Dreams are nice, reality and it's hard lessons... often much less so...

Last edited: Aug 24, 2013
8. Aug 24, 2013

### Rienk

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Well, I'm not necessarily asking for a lesson in composite structures, but I'm not sure what you're saying. We have a stressed skin wing (fiberglass, core, fiberglass), laminated to the full surface of two spars, each with two inch wide caps, and a handful of ribs (also f/c/f) with half inch caps. There is plenty of bonding area to handle shear and peel. How does half a beer can apply to this scenario? I guess I'm completely missing the point, but I don't see a problem, whether the wing is made of composite, aluminum or wood.

ALL of that has been tried? You're saying that nothing new is possible, in spite of possible advances and developments in materials, processes and knowledge? Then why are any of us trying improve on the existing art?
I make no claim to having a magic wand that can do things unimaginable, I'm just trying to puzzle together the right mix that might make something possible. I have no idea if we can come up with a feasible idea, let alone a viable one... I'm just brainstorming.

Here's my premise, again: for sport aviation to have a chance of gaining a critical mass and exponentially expanding - aircraft have to be "affordable" and "available".
I am arbitrarily setting "affordable" for the Acquisition cost of a UL at $20k, and for a two-seat UL trainer at under$40k.
I am arbitrarily setting "affordable" for Training to cost $500-$1,000 to safely fly an UL, $2,000-$3,000 to get a sport pilot certificate, and an additional $2,000 to eventually get a PPL. If you want to debate those numbers, that is fine. I will assert that to be "available", a potential pilot will need to be able to learn to fly at convenient times, at a convenient place. I would suggest this be within less than an hour's drive. This could be at an existing airport, gliderport, or a dedicated flat grass field of 10-20 acres. Available also means that there are enough aircraft available to fly (rent) that a group of friends can go out together. At minimum this would be four UL and one Trainer, but ideally each location would have three times that much (12+3). Another key factor, that is a combination of both "affordable" and "available" is Financing. I believe that any reasonably priced and decently performing aircraft that can be readily financed, can generate significant sales numbers. Of course, this would require a financing model similar to what the auto industry does with their dealer network... one hurdle at a time. To bring this full circle... the UL and Trainer discussed in this thread - for the purposes of meeting the above stated objectives - may be impossible to design and build. A good dose of reality is always necessary; but again, we're in the brainstorming stage. I am hoping that with the collective knowledge, experience and input of other forum members, we might come up with enough viable ideas to make this a reality. I'm not willing to accept the alternative; to wit - keep complaining about the dismal condition of GA, play 'Chicken Little' or bemoan the lack of affordable progress, and then go about the business of designing and (maybe) building a continual array of one-off aircraft that apparently can do nothing to progress the current art. 9. Aug 24, 2013 ### autoreply ### autoreply #### Moderator Joined: Jul 8, 2009 Messages: 10,732 Likes Received: 2,542 Location: Rotterdam, Netherlands Brainstorming is utterly useless in aviation. Yes, everything has been tried out in aviation if you dig deep enough. Show me a single "unique idea" and I show you another project that used the same "unique idea". Brainstorming is simply doing all the pioneering work (99.999999% failures) again. What you need is a thorough study as to what has been tried and when it failed, WHY it failed. Understanding the why is 99% of the work, because then you can discard an idea, or solve it. Sure, there are a few area where we can do considerably better. (More than a few actually and IMHO that includes considerably cheaper trainers). But simply putting up some ideas or listen to what we "want"/"think"/"believe" results in absolutely nothing. Those numbers are irrelevant, though I agree with them. What's relevant is what's a realistic number you can achieve. We can talk all day long about what the customer wants or is willing to pay. But if you can't produce it for that price, it's not going to work. You can't produce it for that price. If you think so, prove me wrong by actually making those aircraft and producing them at that price without a loss. I've talked to a sufficient number of business-owners that weren't idiots to conclude it can't be done for those numbers. I've also done the detailed cost break-downs to conclude we can't do it for much less. I'd be delighted if you prove me wrong, but believe me, reality is a b*tch. 10. Aug 24, 2013 ### Rienk ### Rienk #### Well-Known Member Joined: Oct 11, 2008 Messages: 1,364 Likes Received: 190 Location: Santa Maria, CA (SMX) Okay, I know reality is a hard taskmaster, and I readily admit I'm not the sharpest tool in this shed, so you have me confused. you say brainstorming is utterly useless in aviation - even 6 sigma useless, but I'm supposed to figure out why others have failed - which is 99% of the work - and do so all on my own? You are starting to sound like AirCar... I'm not smart enough to ponder the universe on my own, crawl out of my hole each 'blue moon' and cry "Eureka! I've discovered it!" only to be not-so-politely told that my grand idea is a waste of time, been-there-done-that, go back to your hole and maybe you'll eventually figure something out (although everyone else already has). I don't know of very many people who are able to come up with ground breaking, paradigm changing ideas all on their own in a vacuum. And frankly, I resent the implication that I should try. Nor do I accept that there isn't a possibility that sharing ideas and potential solutions on a forum such as this is anything but an exercise in futility... if so, you're simply a king of the mad-house, and wasting your time even bothering to respond to this thread/forum. If you're telling me - with utter certainty - that this Rubic's Cube can never be solved, then you might as well give up on convincing me now. If you're saying that I don't have the ability to figure this out or pull it off, then again, you might as well ignore this thread - because I've already admitted that. But if there is even a possibility of getting all the colors to end up on the right side, then I'll keep on fiddling with it, and keep on begging for crumbs of help [I'm really good at mixing metaphors], until someone says "solved!" or we come up with a viable solution ourselves. Maybe next month, next year, next decade? Sure glad the Wrights and others didn't heed that kind of advice Head in the clouds and Topaz like this. 11. Aug 24, 2013 ### Topaz ### Topaz #### Super ModeratorStaff Member Joined: Jul 30, 2005 Messages: 13,832 Likes Received: 5,465 Location: Orange County, California Amen, +1, and every other "I second that motion" sentiment I can scrounge up. Stating something is "impossible" with such certainty has been the downfall of even some of the greatest minds in all of human history. Even in aviation. Human-powered ornithopters were long considered "impossible" - many years ago I've seen mathematical proofs of the "fact" that a human couldn't even sustain level flight with an ornithopter. But given some people willing to put in the time and effort to try something new, something difficult, even though it might just be impossible, sometimes leads to... [video=youtube;0E77j1imdhQ]http://www.youtube.com/watch?v=0E77j1imdhQ[/video] And please, let's not get sucked into pedantry about whether this specific expression of the idea is "practical", or "safe enough", or any other such nonsense, or that somehow Rienk's case is "different", etc. That's a canard (old meaning), and nothing more than a deflection. The fact is, these guys took something "impossible" - that had never been done in aviation - and made it happen. Another team from Canada just completed another "impossible" task - a human-powered helicopter. Impossible is a lot less likely than some with really impressive credentials would have you believe. This is a discussion forum. It's not an engineering department. If someone wants to pursue something that you (whoever you are, including me) thinks is absurd, silly, or "impossible", then make your objection and, if it's not well received, then walk away. If the idea is stupid enough, enough people will walk away that there won't be any discussion, and the idea will die the death it deserves. But nobody here has a "duty to set other people straight". Nobody does. It's easy to get sucked into that trap, and lord knows I've fallen for it myself, more than once. Rienk, keep asking questions and keep posing ideas. Not everyone disagrees with you. Last edited by a moderator: Mar 20, 2019 Rienk and Head in the clouds like this. 12. Aug 24, 2013 ### Rienk ### Rienk #### Well-Known Member Joined: Oct 11, 2008 Messages: 1,364 Likes Received: 190 Location: Santa Maria, CA (SMX) Those numbers are totally relevant. Without a defined goal, the task is impossible to achieve. I would never undertake a commercial undertaking such as this without doing the due diligence needed to see what chance of success there was. Granted, some of these projects I'm doing just to have fun, so financial success doesn't have to be assured for me to try them out (hobbies are rarely meant to be create a financial net gain). That is why so many on this forum are hoping to build their own design. It would be great if it turned into something more, but mostly, they just want to build what suits their own fancy. There are two primary forms of successful business. Invent something totally new, and set the price to what the market will bear (think pharmaceuticals, Apple Iphone, most Dyson products, etc). Otherwise, you have to compete on price or features. A new business can earn market share by offering a better product for the same price, or the same product for a lower price. If you pursue the latter - which is what we are talking about here - then you have to figure out what price you need to hit, and how to get there. If you have no reasonable chance of doing so, then it's a waste of time to even try. It's ridiculous to say that it can't be done because no one else has done it before. But it is valid to say (which you have done) that you can't do it by simply doing what others have done before. So, what have others NOT done before? And the question cannot be applied to individual components, such as materials, processes, knowledge or resources. Rather, we need to discern if there is a certain combination of material(s), process(es), knowledge, and resource(s) that MIGHT be combined to reach the goal. That is not to say it is actually possible - only that you can't say it is impossible unless you have considered (if not tried) all of the various permutations. And every time a new variable/option is introduced, you get to go through the process again! Of course, most people give up before the end - very few have the perseverance of Thomas Edison or others of his ilk. Again, this attempt at gathering input from others is simply a way of trying to find some of the necessary connections and permutations. I call it brainstorming. If you have a different method that works for you, all by yourself, let me know how it goes. BTW, I'm just scratching at this - this is obviously not a full time endeavor or even my primary goal. But sometimes, when you keep on kicking over rocks, you stumble on something valuable - that can be used somewhere! This approach has proven very successful for me - YMMV. 13. Aug 24, 2013 ### Head in the clouds ### Head in the clouds #### Well-Known Member Joined: Mar 11, 2012 Messages: 1,983 Likes Received: 890 Location: Gold Coast, East Coast of Australia Once again the conversation has moved on a fair bit while I composed my response but I'll post it anyway - Great post Topaz, just loved the ornithopter, hadn't even heard of that before. OK, I agree, and that is exactly what I said when we had a similar conversation last year. It is the complexity that changes between single seaters and two seaters, and a tandem is also simpler than a side-by-side, by a long way. So if you go from the most basic single seater to a SBS two seater I would contend that's where the amount of work and time quadruples - and that's without adding nosewheel, electric flaps etc. Your example of RV8/RV10 is interesting. The two fellas (chequebook builders) I mentioned before put an RV8 together about 2 yrs ago in close to 6 months. They've been on their current RV10 for about 9 months so far and have hired two full-time and one part-time AMEs to help. Still at least a couple of months to go by the look of it. Not pedantic but very negative .. I'd agree that many of the toothpick tailbooms and similar aft fuselage structures do look lighter than you'd imagine they need to be, and I'd also agree that most of them wouldn't support the 'rule of thumb' previously discussed where the HS should supposedly support the gross weight of the aircraft. Why then, in our (Australia's) extensive history of homebuilt ultralights have we never had a single tail failure from flight loads, not one! The only airborne very near miss that I have ever heard of is well documented and I know it better than most because it happened to my former girlfriend, and I did the repair. The prop separated on a Winton Sapphire pusher and it cut the tailboom 2/3 through. She landed the plane on the highway v-e-r-y gently and the boom folded when the tailwheel touched. So - given that we've never had a tailboom or aft fuse failure, and also given the wild aerobatics that many of our folks have posted on Youtube, perhaps the 'rule of thumb' is a bit excessive? Maybe in actual practice only one of you has to be supported on the HS? Your comment about 'looking impossibly thin', I'm thinking you're referring to the tailbooms? They have internal doublers at the forward end for about half the length of the tube. I agree that it's not easy but as you've often pointed out the 'real' price (adjusted for inflation, wages etc) of aircraft is much less now than it was in ages past. That means that prices are being brought down by the efforts of people trying to reach the market so I think Rienk deserves encouragement. The major problem I see is that people expect to make large price reductions all in one go, and often without any specific new technology or material or significant increase in production volume. Many people getting into manufacturing aren't aware that on average the retail price is approximately 7x the ex-factory cost price. It might not be quite as much as that in the case of aircraft but would still be at least 4x I would think. In which case if the target for retailing a cheap trainer is$40K then it must come off the production line at $10K or you'll be working your way into debt. 14. Aug 24, 2013 ### Rienk ### Rienk #### Well-Known Member Joined: Oct 11, 2008 Messages: 1,364 Likes Received: 190 Location: Santa Maria, CA (SMX) Uh... that comic doesn't make sense to me... being an Aspie, I assume everyone does that? As I joke with my kids, I'm CDO. It's like OCD, but in alphabetical order, like it should be. 15. Aug 24, 2013 ### Rienk ### Rienk #### Well-Known Member Joined: Oct 11, 2008 Messages: 1,364 Likes Received: 190 Location: Santa Maria, CA (SMX) Great! Since you guys have had this discussion last year - we can not repeat the entire thing on this thread - marvelous! As to reducing aircraft price, it can eventually be done incrementally - though the major factor there is simply quantity. Other than that, there has to be a paradigm shift - which, contrary to most people's expectations - can actually be toward "lower" technology. For example, let's look again at the plane in my avatar - the Solo. The concept was originally to counter the ever increasing prices of existing LSA's. I figured that a two-seat LSA would probably be well received if it could be sold for under$60k. But because we were broke at the time, the best I could do was work on developing a single-seat POC.
At first, we were going to try to sell it RTF for around $20k. Though it might be possible to do so, that would not allow any profit, and that didn't sound like a viable enterprise. So now, we are shooting for under$30k, which should allow a successful business model. Of course, the appeal of a single-seater is exponentially less than the two-seater, so that would be forthcoming, should the POC prove viable.
I've already listed what we are going to do differently than everyone else to reduce costs - the major areas being labor, engine, and avionics.
We don't pretend that we'll sell a plane for this price that will be the same as the current offerings - I'm not that arrogant (I hope).
But we do expect that there will be enough people to accept the differences in exchange for getting a reasonably similar look and performance at half the price.
That is definitely a bodacious goal... even if we don't make it, we'll hopefully have fun trying!

Based on what I've read on this forum, I've been wondering if the same is possible for a lighter weight, lower-class pair of aircraft - a UL and matching Trainer.

Still looking for enough positive input to try to fit the pieces together.

AR has given some good ideas to consider; a few more and we might be able to do an actual feasibility study!

16. Aug 24, 2013

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Therein lies the key.

Exactly where do you expect to find the "enough people to accept the differences"?

Ithink this is where a fair few people fall down when trying to get intothe airplane selling game. Those interested in and capable of buildingplanes are often less skilled in sales and marketing. Instead of"expecting that there will be enough people" out there wanting to buyyour product why not settle it in your mind that there is no-one at all that is interested in your plane, or anyone else's plane come to that.

Ifyou approached the whole project that way you would start by workingout a method to create your own market. Get yourself out of theposition of having to compete for the tiny and ever-shrinking existingmarket. Find a whole new bunch of people that haven't ever consideredflying before and get them addicted to flying. Work out how tophysically introduce a non-flying public to a whole new way of life.How will you make those millions of people out there want to fly? How will you make them not be able to live another day without being able to fly whenever they want to? Why will they choose your plane once they absolutely must fly?

Ifyou wanted to sell a new Cola would you just make it cheaper and a fairbit inferior and hope that the price is enough to find "enough people to accept the differences"?

Ithink trying to sell planes in a declining market and during a pooreconomy is about as difficult as introducing a new Cola but I alsodon't think it'd be impossible, it would just need a whole newapproach. I wouldn't work on trying to convert anyone from anotherbrand, those people will come along later when they see others enjoyingthe new version. I think I would go out and actively find people whodon't presently drink Cola and show them why my whole new product willplease them. It's generally known that reduced price alone won'tconvert into significant sales, people are suspicious creatures andparticularly in aviation, so you'd spend all your time trying toconvince people your product hasn't resulted from corner-cutting.

Iused to know a lot of the people who had ultralight flying schools and it wasinteresting to see which ones were more successful than others. Onelocal excellent instructor and school owner used to bemoan that acouple of the other schools were doing really well financially and hebelieved it was because they had the distributorships for a couple ofthe production aircraft, and profit from the planes was their key tosuccess. The truth was far from that in fact, they made a little profiton the planes they sold but the obligation for stock-holding andhangarage and parts supply was a big weight against it. The reality wasthat those school owners were very good at actively recruitingstudents, the less successful schools were the ones that sat back andwaited for students to come to them or tried to compete for the fewpeople who showed an interest at fly-ins, instead of finding acompletely new source of suitable people and showing them why they needto fly i.e. creating a completely new market.

The beauty of having your own independently created market is that it'sbottomless, it's as big as you make it and you're not competing withanyone. Not only that, the more similarly minded people get intocreating their own new airplane market, the better. There's no shortageof people in USA and the more people that work on market creation themore aviation gets publicised so the easier it becomes to influenceyour target market. It's a good example of why co-operation is morepowerful than competition in the longer term.

EDIT - apologies about the formatting - the site is fighting me again

Last edited: Aug 24, 2013
17. Aug 24, 2013

### Rienk

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It's the Apple debate - did they invent a new product that people realized they wanted, or did they decipher what the market needed, and designed a product that met that need in a fresh and innovative way.
But eventually, new technology becomes a commodity, and the market has to compete on price (even Apple). The only way to have a chance to stay above that fray is to continually innovate. Harder in aviation than in consumer electronics.

To be honest, I'm not going to start by trying to create a market - I don't have the cash flow for that.
At first, we'll go after the low hanging fruit - those people who are pilots or intend to be, and are interested in a lower cost airplane.
After that, we intend to try to convert a different market, by going after people that are already interested in motor sports... motorcycles, atv's, jetskis and snowmobiles; I'll also go after the moneyed sports... golfing, skiing, etc.

If/when there is steady growth, we'll go after different segments of the general population.

Obviously, the airplane has to be a good value - well designed at a fair price.
But the key is still availability - driven by financing.
In high cost items, a mediocre product that has easy purchase/finance terms will outsell a better product that must be paid for in cash.

Nonetheless, none of these points by themselves is the key to success - it is the overall package.

(too tired to finish this thought, I'll try again later...)

18. Aug 24, 2013

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Tail booms, some of the struts, some of the attachments.
As for the "no structural failures", true enough. But the same was said about the Zenairs and the Duo Discii, even after two Zenairs collapsed happily cruising along without any turbulence or manoeuvres. I'm aware of at least one plane where you would reach strut attachment failure at something like 2.8G. Never failed in the many flights in some pretty wild conditions. IMHO, using up the normal safety margin (50% of limit load) and then some more is recipe for disaster. The "rule of thumb" is simply what you typically get at 4G+50%. Not a lot of excessive margin there either and I bet you would'nt get into a Cessna where we've cut 2/3rd of the tail or wing spar/strut away?
Yup. Production (labor) and material is ony a tiny fraction of the sales price. If you were to do production for free and get the materials for free for a typical LSA, you'd still only save 25% of the cost.

Google the Atlantica BWB and the Verhees Delta and imagine a love-child of those two. Can't do much better then that in reducing parts count and thus cost, because you only need 4/5 parts plus a canopy.

19. Aug 24, 2013

### Rienk

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HUH?

How do you figure that labor and materials are only 25% of the cost?
Are you excluding engine and avionics? Interior and Finish/paint?
If you're selling a RTF aircraft, those obviously have to be included.

Labor and (all) materials are easily 75% of the cost.

I used to follow the Atlantica - that is a sexy design. Reducing parts count is great, but it still needs to meet the weight limit (and there's no way I can afford the R&D on something like that anyway).
I'm also familiar with the Verhees Delta. An ungainly little bird, but apparently good perfromance. Still, it doesn't excite the non-pilot to want to learn to fly.
I would think something along the lines of the KasperWing would be a better choice.

Still, I am of the opinion that a more conventional design will be necessary. Though folding wings is a 'must have' feature.

20. Aug 24, 2013

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