# New Ultralight and LSA Trainer design PAIR

Discussion in 'Aircraft Design / Aerodynamics / New Technology' started by Rienk, Aug 1, 2010.

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## What is your interest/input in such a project?

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1. Aug 1, 2010

### Rienk

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Sorry about the poll being first - it was supposed to be after this first post. Please read this and then respond to the poll. Thanks, RA

Intro
One of my passions (beside designing or building things) is to see young people get involved in flying. It is obvious that to do so, we need to make entry into the sport easier.

To accomplish this, I believe that there are several factors; low cost "beginner" airplanes that are safe and fun to fly; low cost operation and easy transportation; as well as flight training and mentoring. While this is not about the latter, I will reiterate that we need to pass on our legacy and enjoyment of flying to the next generation (such as LEAP, Young Eagles, etc). This subject deserves many threads of its own.
Though I am thrilled with the development of the LSA category, most of the aircraft being "produced" are still much too expensive for beginning pilots; flight schools are not yet jumping in with both feet, and consequently, there are not enough "used" aircraft available for the less well heeled pilots to acquire.

Part of the LSA objective seems to have been to fill the low end gap, and remove the problem of 'heavy' ultralights, while also allowing a means to build aircraft that can provide primary instruction for those interested in starting with 103UL flight... but this is not happening.
I believe that Leanord Milholand's 'Legal Eagle' and 'Double Eagle' together form a good example of how to possibly offer low cost flying to individuals with an ultralight (LE) while having a trainer available (DE) that will give truly compatible flight training. But since neither are 'production' aircraft, I do not believe they will have the momentum to make the significant change envisioned (to reach the "Tipping Point", a book that I recommend for this topic).

Concept
I am convinced that what is needed is a concerted effort from a group of like minded people to collaborate on the design of two new aircraft, with similar flight characteristics and building materials.
Thus, I am putting out the challenge to this group to help develop such a pair of aircraft. Though it will probably be a commercial venture, it will likely not be very profitable, so any involvement would have to be primarily for “love of the game” more than for any dreams of financial windfall. This would primarily be a “Pay it Forward” project. Nonetheless, I would suggest that every serious contributor would at least have a chance of recouping their investment of expertise or resources, and thus will put together some sort of “point” system of payback. But let’s not put the cart before the horse…

Ideas
The following list are my ideas of what might be a good design solution, simply to get the conversation going (these are top of mind, so not necessarily in any particular order).

• Looks like a "real" airplane (market acceptance).
• Four stroke engine (I favor the Generac, which is used quite successfully in several other UL designs, as well as mini Air and Mud boats).
• Both Taildragger and Tricycle options (with the same airframe).
• Tube and Fabric design. I would like to explore welded aluminum tube.
The weight is significantly less than steel, allowing for thicker walls and/or larger diameters. I know that TIG welding will ruin the temper, but it seems that if we designed with T-0 for the joints, and T-6 for the rest of the tubes (which are basically concerned about compression and buckling), then it shouldn't be a problem.​
• Probably High Wing
easy roll over protection, and lighter weight by using struts.
Ease of entry and egress (lot more appeal if you don’t have to be a contortionist to get in – sit and turn).
I believe that folding wings and/or trailerability is a necessary feature, so either removable wings (a la gliders) or folding.​
• Removable Horizontal tail (bolted on, with fail safe elevator connections. Elevator aft of rudder).
• All flying Rudder (better cross wind capability… just an idea).
• Composite Wing.
Plywood or fiberglass cored D-section, CF spar caps (I'm not sure about web), maybe wood or plastic (injection molded) ribs, and everything cloth covered. With fiberglass for the first 40+% of the airfoil, a laminar section could be used, vortex generators mounted, and then lightweight fabric on the rest (where it doesn't matter). The weight may not be any more than other types of wings, and potentially allows for much smaller wing.​
• Large slotted Flaps (with hinge points down and back, to mimic Fowler).
• Scooter tires and wheels (large for rough ground, and wider than bicycle tires for side loads).
• Long engine mount for base engine, so that other (larger) power plants can be considered for LSA use/upgrade.
• Completely fabric covered for aerodynamic cleanliness and comfort (all weather flying).
If the design is too clean for max UL speed, have other drag increasing options (again, for LSA speed capabilities later).​
• Ballistic parachute standard (safety, but also 'extra' empty weight margin it allows).
• Good Wingtips (at least as an option).
• Electric start (don’t want even the likelihood of kids hurting themselves hand propping).
• Basic electronic instrumentation (something like MGL’s Flight 2 and Engine 1)
• Electronic accessory pod (quick connect for radio, gps and/or moving map).
• Door option (if they’re not required for flight, they don’t count against empty weight; nice for LSA upgrade).​

Wrap up
I’m sure there are a lot more things that could be considered, either as additional or replacement design goals. This is only my wish list.
If this ends up being a collaborative project, the team will have to decide what is best, what is feasible, and then what is viable.

Anyone interested in taking this on? I have no idea what is a realistic time frame for a group effort like this, but it would be awesome to have a POC or prototype by Oshkosh next year!?!

For those who are interested in being formally involved, please contact me by PM or on this forum.
Even if you are just casually interested (or just heckling from the bleachers), any and all feedback and constructive criticism to this concept (or the initial list above) would be greatly appreciated.

Last edited: Aug 1, 2010
2. Aug 1, 2010

### Inverted Vantage

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I would be interested but I doubt I would be as useful as some of the others on this board. That, and I have a bit of a different idea about attacking the problem.

3. Aug 1, 2010

### Autodidact

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Don't sell yourself short, you're in a good place to participate and it's all good experience. And even if your ideas are different than the project manager's, your input could prove useful - both to the project and to your own development.

4. Aug 1, 2010

### Autodidact

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I think that what is needed is a structural scheme that will result in a strong and neat structure with the least amount of labor. And don't discount the selling point of "Made In America".

The extrusion idea seems to me to be the most fruitful w/respect to low cost. If you could develop a set of extrusions that could be bolted together with a minimum of fasteners, I think you could have a neat looking and labor economical airframe.

5. Aug 1, 2010

### Rienk

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I understand your comment about "least amount of labor", which is specifically what we are doing with the SOLO sport plane. However, the required flight parameters of part 103 do not allow for such materials. I will edit the list in my first post to include "REAL looking airplane." The market doesn't need another "sticks and wires" type of ultralight - it needs something that the owner's friends will say "wow, that looks like a neat little airplane", not "you'll never get be into one of those things!"

Unless you can offer a material choice other than tube and fabric that can do this, i don't think there is much choice but to count on a large labor component. And using lots of carbon pultrusions (like the Dragon plate system) is outrageously expensive!

Believe me, my preference would be to do a nice blended composite fuselage, but there's no way to keep the cost down with the weight low enough - I see no other option than rag and tube fuselage.

As far as made in America, I'm not going to worry about that. Even Cessna and Piper won't do it for their LSA's, and it hasn't stopped the many hundreds who are lined up to buy them.
As much as I philosophically agree with you, building it in America will surely double the price, which will lose 90% of the sales - not a viable trade off. I've done a lot of studying on this issue with several of our other businesses, some of which we manufacture for solely in the US, and some which make sense to do offshore.
The bottom line is, labor cost does not need to be an issue, so we need to find the lowest cost option in regard to materials and components.

6. Aug 1, 2010

### Rienk

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One of the initial goals of this thread is to get ideas on how best to solve the problem... what do you think the best concept would be?

7. Aug 1, 2010

### Autodidact

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Actually, I did mean aluminum extrusions, or maybe stamping. Could you stamp out a truss, fold it up and then rivet a single seam along its length?

Also, the 103 limitations are so stringent that it will be difficult to share an airframe between 103 & LSA IMHO (or did I misinterpret the concept?). Perhaps the configuration could be the same with the LSA just made bigger - could use the same tooling and process.

Last edited: Aug 1, 2010
8. Aug 1, 2010

### PTAirco

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I think the design constraints for Part 103 and for LSA are so different, it would be hard to build them along similar lines. True ultralights that look like real airplanes are very difficult to design - I have been playing around with the concept for years. The trouble is saving ounces here and there in the hope of saving a pound or two calls for a very different design approach. And it can
become very labor intensive and/or expensive. The tube and fabric structure is about the only option you have. I believe the welded aluminium tube structure is worth investigating - as you said the center of the tube should remain fairly unaffected by the welding and this is where the buckling/bending strength is most needed. The cost of 6061 vs 4130 is of course significantly less, but it would be a close contest, weight for weight, with a well designed steel tube fuselage.

The LSA requirements are of course also very weight critical, but far less so than the Part 103 design and pretty much any choice of material could be made to work, so the choice would boil down to cost; material and/or labor.

9. Aug 1, 2010

### PTAirco

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Curiously along the same lines of this topic I recently posted this on the National Aeronca Assoc. forum, just a few days ago:

I would love to be involved in a small scale airplane building business taking advantage of the LSA market. There are literally hundreds of Cub-clone LSAs out there, proving the market is there. All of them insanely priced; 100-160k!! I am not an altruist by nature, but I have enough passion for this industry not to let greed rule me - you can build similar aircraft and sell them for 50-60k and make a decent profit. You can hardly buy anything in the LSA market under 100k these days. Selling at anything less than an outrageous price instantly expands your potential market.

Think how successful the Cub-clones are; mostly based on the innate appeal the Cub has to many people. Now think about the how the original Champ came about and became so popular; it took the appeal of the Cub, with its shortcomings designed out of it and made into a better flying machine. There is no reason in the world a Champ-clone should not outsell the Cub-clone, especially at a decent price.

Aircraft production engineering has long been an interest of mine - with modern machinery a lot of the man hours can be easily cut out of it; CNC profiled tubing that fits together for welding with no further work, water-jet cut fittings, CNC routed ribs - you name it. I read somewhere the Cub required only about 300 man-hours to assemble (I assume that meant assembly, not actual fabrication), and doing a brief analysis tells me that that is not far off the mark.
Looking at it another way - a Cub originally cost about $1000 back in 1938 and the average worker made about$1,700 a year. Since then wages have risen by a factor of 25, so given an equal sales volume, one ought to be able to sell a similar aircraft for $25,000 for a similar profit margin. OK, let's be realistic and say$60,000 - that is still 40%-%60 less than any other similar LSA out there. Believe me, I have looked long and hard at these numbers over many years and it's certainly do-able.

The real appeal is that the aircraft design is proven and beyond reproach - there would be almost no development work involved, apart from finding places to cut man-hours and take advantage of modern production facilities. There would be virtually no risk from a design point of view and judging by how well the original Aeroncas sold, they should do equally as well as the modern Cub-clones. (Yes, I know American Champion is trying that, but their LSA Champ is so overweight, it's virtually useless as a two seater.) I mention the Champ as probably the most suitable design for a project like this, where sales are based partly on pure appeal more than technical factors, but having spent a long time staring at (and sitting in!) the L3 project I have in my shop, it strikes me as a perfect design for the LSA market, mainly because of its comfortable roomy cockpit. It just isn't as well known as the Champ.

Aviation is slowly being priced out of reach and the whole LSA business, which was supposed to reverse, that has failed in bringing reasonably priced airplanes to the market, even with the comparatively simple certification process. Only by having a company committed to bringing back sanely-priced aircraft can that trend be reversed. Aeroncas were designed from the outset with similar goals - they were supposed to be affordable; no reason why they would not do well in this market, given a company dedicated to those goals.

Like I said, these are hypothetical musings; if I won the lottery tomorrow, I'd go for it - but right now all I have to offer is "blood, sweat, toil and tears", like the man once said. Heck, banks won't even give me a 25k loan for a Champ without 26k in collateral !

Note my point about the relationship between price and income when the Cub came out and the figures for these days!I was inspired by my Aeronca L3 project which I came across in April and I have been studying it in detail as it is sitting in my workshop. Not a widely known airplane, it has fewer of the shortcomings of the Cub (far roomier inside, front seat solo, etc) and would make a great little LSA, powered by anything from the new O-200, Jabiru, Rotax etc.

10. Aug 1, 2010

### KeithO

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Definitely, the part 103 needs to be powered by the lightest possible engine, even if it is a 2 stroke. A light engine allows for a bit of structure and better crash worthiness.

The Hirth F33 is 40lb including a redrive @ $3200. F33 #### Attached Files: • ###### F33 pic.JPG File size: 84.2 KB Views: 4,298 11. Aug 1, 2010 ### Rienk ### Rienk #### Well-Known Member Joined: Oct 11, 2008 Messages: 1,364 Likes Received: 190 Location: Santa Maria, CA (SMX) Stamped parts can have the flanges formed at the same time (if they are simple 90 degrees or less). However, the tooling is fairly expensive. When I mentioned the LSA option, it was only in the sense that it should be very easy to make simple modifications to the UL version that would drive it out of the limitations. for example, a cruise prop instead of a climb prop might allow it to go 70-80kts instead of the 55 max for UL. A larger engine could do the same; a larger fuel tank for greater range; a better instrument panel that adds some weight, heavier gear that can handle rougher ground, etc., etc. Thus, I am not talking about optimizing for the LSA rules, but rather allowing a customer to upgrade the plane with minor cost or change. The main reason is that both UL and LSA can be sold RTF (ready to fly), which is where the cost savings can be had in production. The goal for the single seater is UL, with the option to bust the restrictions and still buy a RTF airplane; but the goal is NOT to try to compete with purpose built LSA. Ultralight is the main purpose of this plane. 12. Aug 1, 2010 ### Rienk ### Rienk #### Well-Known Member Joined: Oct 11, 2008 Messages: 1,364 Likes Received: 190 Location: Santa Maria, CA (SMX) That is the point of my last post... a purpose built UL that has the option to bust the speed-weight-fuel restrictions and be registered - while still being built RTF. 13. Aug 1, 2010 ### Rienk ### Rienk #### Well-Known Member Joined: Oct 11, 2008 Messages: 1,364 Likes Received: 190 Location: Santa Maria, CA (SMX) We would love to have you involved! But to comment on your point about the Cubs, I would be cautious. Just because there are lots of companies selling Cub clones, doesn't mean there is much of a market for them. In fact the overall sales numbers for such planes (especially LSA) is dismal. However, this may be largely due to cost, so the key is finding the blend of the right price point while still maintaining a profitable and healthy company. I agree, that is why we are developing the Solo and Duet line of LSA, which are all composite aircraft. However, the market niche being proposed here is even lower than that price wise. If it were truly possible to sell 103UL that looked and flew like a "real" airplane for under$10k, you could probably sell thousands of them. However, I don't think that price point is realistic for a commercial venture, so we need to find out where the sweet spot is, and work the numbers backward from there.

Think how successful the Cub-clones are; mostly based on the innate appeal the Cub has to many people. Now think about the how the original Champ came about and became so popular; it took the appeal of the Cub, with its shortcomings designed out of it and made into a better flying machine. There is no reason in the world a Champ-clone should not outsell the Cub-clone, especially at a decent price.

Though I don't think any airplane can be built in 300 hours, I agree with your premise. Henry Ford made his fortune by doing that with cars.
So, is \$25k for a new Cub/Champ style aircraft a reasonable figure for large sales numbers here in the US?

AMEN!
There is room for many designs and style of aircraft that can do this. I see this project as being the "intro" to flying, and a stepping stone for people to commit to aviation and move up to other designs (such as the Solo/Duet, or any others that this group may independently develop and market).

[/UOTE]Like I said, these are hypothetical musings; if I won the lottery tomorrow, I'd go for it - but right now all I have to offer is "blood, sweat, toil and tears", like the man once said. Heck, banks won't even give me a 25k loan for a Champ without 26k in collateral ![/QUOTE]

So that begs the question - do you want in? And what part do you want to help with?

[/I]Note my point about the relationship between price and income when the Cub came out and the figures for these days!I was inspired by my Aeronca L3 project which I came across in April and I have been studying it in detail as it is sitting in my workshop. Not a widely known airplane, it has fewer of the shortcomings of the Cub (far roomier inside, front seat solo, etc) and would make a great little LSA, powered by anything from the new O-200, Jabiru, Rotax etc.[/QUOTE]

14. Aug 1, 2010

### Rienk

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Hi Keith, I appreciate your input, and I understand your reasoning. However, I disagree with you on this one.
Right or wrong, perception of the two-strokes does not make people feel safe. And from a marketing perspective, few people are willing to spend the kind of cash we are talking about to fly behind a "weedeater". They want to show off their sport vehicle, not make excuses for it.

Probably the only hard and fast requirement of this project - other than looking and flying like a "real" airplane - is that it have a four-stroke engine.

15. Aug 1, 2010

### Autodidact

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The two dimensional truss (like on the afford-a-plane), filled out w/lightweight formers/fabric seems like a relatively quick and simple way to build a fuselage as well as potentially light.

16. Aug 1, 2010

### Rienk

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Just to make sure everyone is following my train of thought, I will clarify this.
I am proposing that we design two completely separate aircraft.
One as a single place 103UL, and another as a two-seat LSA that can be used as as training platform for the UL version, as well as in inexpensive aircraft in its own right. I am NOT suggesting that they two airplanes share any components in common - just the building materials and flight characteristics.

When I mention the UL to LSA upgrade option, I am ONLY referring to the single-seat design. Thus, the plane can be offered as a true 103, or as a "heavy" UL that is actually (legitimately) manufactured in the LSA category.
Unless the price point of this aircraft is virtually the same as the UL, I don't see a huge market for this aircraft; it is simply a concept to allow purchasers of the UL to "transition" to a different flight regime without having to necessarily buy a new airplane.

In all likelihood, many people upgrading will likely go directly to the two-place model instead, or even to other low cost LSA that are bound to come out (such as the Solo and Duet). Yes, I confess that I also have an ulterior motive for this project - though it should help everyone who plans on having entry level LSA designs (which is why we should all be working together on this project, kind of like all the car dealers being together in an auto mall).

17. Aug 1, 2010

### Autodidact

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18. Aug 1, 2010

### Monty

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Part of the problem is we have to stop thinking like airplane people. We have this built in bias of how things have to be done. That thinking has got to go. No offense to the aerospace guys, but your training is a liability in this instance. That training is required to build airliners and fighter jets. Aviation is a captive of those industries and the regulatory bodies built around them. We have to get out of that mode.

Forget patents, forget all that crap. Just do it. Disclose everything you do publicly so no clown can try to patent around you. Use the Gnu licensing scheme.

Lets say we take aluminum tube. Then we make some Thixomold split couplers. Then we do something like take a steel compression ring that is swaged over the ends. No welding, no metallurgy issues. No skilled labor required. It's also possible to use carbon pultruded rod which is not so expensive in this manner. Think Geodesic tent. You glue the rod into the thixomolded couplers.

Then instead of fabric, what if we use a heat shrink plastic film over the outside-UV stable of course. Forget all that labor putting on the covering.

Vacuform the doors from PEET or something similar. Paint on the inside. Same for the cowl and any fairings, wing tips etc. CNC bend the tubes and any stiffeners for the doors. In fact you may be able to vacuform wing and other control surface skins. Just build the internal wing structure to take the loads. Instrument panel-vacuform.

Use CNC router to make vacuform tooling. Build your own vacuform machine. This keeps the tooling cost reasonable.

I'm thinking like a plastics, sporting goods, and consumer products guy.

Just throwing some ideas out there.

Trade studies and cost analysis need to be done very carefully. Also environmental degradation, and maintenance criteria.

But, whats tried and true will not get us out of the  pit.

Monty

19. Aug 1, 2010

### Starman

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I'll think about being project leader if the plane looks like my avatar

20. Aug 1, 2010

### Monty

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I disagree entirely. For many reasons the main reason being cost.

That engine is 2X the retail cost of a 4 cycle industrial engine.

The next reason being market acceptance. I'm sorry but two cycles have long since been relegated to chainsaws and weed eaters in all realms of consumer products. They are currently under attack even in these markets. I like them just fine, but they have operational issues that do not lend them to being ideal for the novice. They are noisy, they stink and they are perceived as dirty. We are going to have to think like product designers, not engineers for this to work. The very first thing that has to be done is make sure that the market will accept your product, then you worry about the engineering.

I think that the two cycle looses on all counts other than wt.

Monty