# Collaborative Design Challenge – Working Together to Create a Plans-Built Design

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#### Nims11

##### Well-Known Member

As the title says this thread is an attempt to launch group collaboration on an airplane design of a specific type. Before going into what that specific type is for this particular project, and the details of the project itself, I want to point out that this specific airplane design will likely not be anyone’s “dream plane”. And surely the question will arise, why design this type of airplane – why bother? There are a couple of reasons. First, to establish a process that actual works. For this initial project the emphasis needs to be on it being successful, because if it is not successful then it is a waste of time. But moreover, if it is successful then the process itself could be a model for future collaboration for those that want to see the creation of a design that is perhaps more challenging and rewarding, or of particular interest to them. And to that end I’m choosing an airplane design that is fairly moderate to help make the success of this initial collaboration realistic. Second, in my opinion there are few really good plans options out there that meet the goals of this particular design, actually in my opinion there are none. In fact, unless you have a fat wallet, and a bunch of free time, there are few really good plans available at all.

I am absolutely certain this could be a successful and rewarded project. But to be so, there are several absolutely essential principles that must be strictly adhered to with discipline, moreover group discipline which in my experience is even more difficult to maintain. There are two general areas where these fundamental principles must be adhered to for this to work. The first set of principles are in the collaborative process itself. These are the things that we must always come back to and remember as a group to make the project go forward and be affective and successful. This is the most important part, and absolutely essential for this to work. The second set of principles (if I can call it that) is in the goals of this particular design. Those primary goals will be fee, yet limiting in order to keep the design manageable.

The principles that must be adhered to for the collaboration aspect to work are as follows.

1. Participants must be willing and able to compromise, and thereby go beyond their individual egos for the greater good of the project. This is probably the most significant point. I have been in many group projects and meetings were absolutely nothing gets accomplished because of general disagreement, and incessant bickering, that leads to long wasted time with no results. In my experience this is largely because people come into these groups with strongly held opinions and beliefs, which often come from a limited viewpoint, yet which they equate to be “life wisdom”, and to which they will have absolutely no compromise. It is good and necessary to have opinions and beliefs, and share your real experience. But if you are not coming from an open disposition that allows for the possibility that your way may not be the best or right way, then no forward progress is even possible. You must be open to compromise.

2. Participants must be motivated and committed to this project for one of two reasons. Either they are really interested in this particular airplane design and really want to build and fly one for themselves. Or, they are moved to be a part of this project for the sake of, or in the spirit of, the collaborative process itself. Some may find such a process to be a creative outlet, or simply enjoy sharing their knowledge. Or, as in cultural movements like “Open Source”, they want to contribute their efforts, or ideas, or knowledge, not merely for the sake of the all-mighty dollar, but rather to see it come to life and be disseminated and made freely available to all for the better good of the community. Also, for some who are working in this specific field, they might find this collaboration an outlet to see their work manifest in a built and flown airplane, which they were a part of, and which otherwise may never come to be. Consider that the vast majority of people who think up a design, and even worke on it for years, have never, or will never, actually build that design much less fly it. A collaborate process might be the answer to making ones efforts, if not their personal goals, come to some objective fruition. I am not suggesting that anyone abandon their own project. You can continue your project (or take a break from it) and still participate in the collaboration on the side. And perhaps you just might find renewed inspiration and ideas to help make your design a reality. In any case, the point of this second principle is that if you do not participate with real motivation, and are just hanging out to see what is going on and quick to criticize every step and point out how it won’t work, then this process will not work.

3. There must be an orientation and disposition relative to all design problems as solutions that need to be discovered. In other words, this has to be a process of solving problems, not merely identifying problems (potential or actual) and then meditating on them and elaborating on how they cannot be overcome. There are some “problems” that cannot be overcome, physics cannot be denied. But that does not mean that workarounds and creative solutions cannot be made. Energy should always be directed at solving the problem, not dwelling on it.

4. There must an emphasis and discipline on continuously moving forward, and completing the project in a timely manner.

5. Lastly, I feel there needs to be one to three leaders of the core group. Perhaps one would be the senior engineer, another a experienced composite builder, and the third a project manager, which would assist the engineers with allocated tasks and organizing and managing the project as a whole. Additionally there would be a core group of which these 3 would be a part, with perhaps and additional 2 or up to 8 people who would vote were indecision about how to move forward came up.

For the particulars of this airplane design, there are general design goals, or principle that must be adhered to. Again, these are very general, but as we move forward more details will be established in stages. That way we are sure to not bite off more than we can chew and get bogged down, or overwhelmed, with too many variables.

Also, before getting into the goals, I want to point out that the general characteristics of this design will be similar to a Diamond DA20. Using this plane as a model or guide will keep the design focus narrow enough to make it realistic and perhaps even relatively easily achievable. This is not a project of producing a DA20 replica; I’m using it as a guide for a plane that will have very similar characteristics. Along side the DA20 I want to put up also as general guides two other airplanes that can be viewed as ends of the spectrum. On the left side is the Flight Design CT line of aircraft, and on the right side is the Cirrus SR20/22 line. Both these planes are quite different, I understand, but I feel they are useful as reference points, so to speak, as well as for barrowing ideas and technologies from them. The DA20 fits somewhere in the middle of these two planes, I believe, and is more of a balance, or more moderate, and thus might appeal to a larger group. So, with that the general design goals are as follows.

1. All composite structure – less parasite drag and greater design flexibility.
2. Conventional design 2-place – for reasons already stated. This does not exclude modern innovations or new technology in aspects of the design. For example, winglets might be used as an important modern implementation for efficiency.
3. Low build time – in the range of 1500 hours. I know, not possible right, but it can be. This may be one of the biggest design hurdles but I believe it is also the most important one. Many projects are not started, or abandoned, because they take too much time.
4. Cost under 30K.
5. High efficiency.
6. Comfort.
7. Excellent stability and safety.

Let’s look at some of the details of how the project could work and be managed, and what tools can be used to make it more effective. This forum is a good place to introduce it but to actually get any real work done it would be best to move it to a website created for the project. Anyone can access the website and contribute but only after they have stated they want to contribute and then given a password. Also, the files, like the actual plan, spreadsheets, and 3D models can be uploaded to a repository like Github with access given to all who are participating.

As stated previously there needs to be a core group, or leadership team, however you want to call it, which will act to make final decisions about how the design will evolve. This group should be at least 5 people but maybe up to 11. One person will be the engineering leader and another the project manager to assist him. Odd number because the group will vote were there is disagreement (which there almost always will be), this way we are not endlessly going back and forth arguing over the design options.

To bring does cost and time, not only will the design be a collaboration but the build itself could be a collaboration also. Some of the inefficiency in time and cost could be reduced with a collaborative effort. For example, say you just made a really nice mold for a wing half. You took a detailed 3D file of the part that was provided in the plans, and CNC cut a plug, and from there made a mold out of fiberglass. After you make the part the mold is basically worthless to you, as you won’t likely use it again. This is an inefficiency in time and expense. But if you were collaborating with others, who lived in the same general part of the country let’s say, you could share the mold. Say you have 5 guys that are part of a build group, and each one started at a different point in the plans, one would start making one side of the wing, and another the other side, another the fuse, another the tail, maybe another the cowling. Once each had finished with their piece they would send the mold to another person. That way only one person would have to make one mold.

For the engine and prop of this design, which is the single biggest expense, I was thinking that we could build into the design the allowance for 3 options, the VW Aerovee type at 80hp, the 100hp Rotax, or the Jabiru or rotax 120HP. This is similar to what is offered with the Sonex. If you wanted a cheaper plane with less performance you can use the inexpensive VW, if you wanted better performance you can pay a bit more.

This is getting to be an overlong post, and I’m not sure if there will be any interest at all. So I'll stop here and see if there is any feedback.

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#### Autodidact

##### Well-Known Member
Welcome to the forum Nims11! I don't know anything about composites so I'm already out. I'd love to see something like this happen though, because it could be very interesting and informative. The level of engineering is pretty high or can easily be, depending on the approach taken, and unless the world has changed somehow, I think you'd have difficulty getting a group of forumites to collaborate on a boxkite successfully, much less some fast glass! I say this because I am as guilty as anyone at trying to start/participate in something like this. However, life is constantly full of surprises. There are some simple techniques and a French guy has built a very nice F1 racer using a relatively artisanal approach. I point this out because the more complex the manufacturing and design of the airplane is, the more opportunity there will be for disagreement. Good luck, though!

Maybe you could capture the imaginations with a 3-view drawing?

By the way, this is a very poignant statement:

...people come into these groups with strongly held opinions and beliefs, which often come from a limited viewpoint, yet which they equate to be “life wisdom”, and to which they will have absolutely no compromise.

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#### SvingenB

A bit too much focus on design perhaps? And composite? No homebuilder (very few at least) is able to work with composite structures like that of Diamond aircraft, or Cirrus etc. These structures are designed for batch production with a minimum number of airframes to start paying off the production equipment, you are talking about plans built. Maybe some foam, Burt Rutan kind of thing, but I don’t think it’s the best option for long slender wings like the DA20? Good luck anyway.

I am all aluminium though

#### BoKu

##### Pundit
HBA Supporter
...No homebuilder (very few at least) is able to work with composite structures like that of Diamond aircraft, or Cirrus etc...
My customers do.

Thanks, Bob K.

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HBA Supporter
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#### SvingenB

Cool but that is hardly plans built in my opinion? You need molds and stuff don't you?

#### Nims11

##### Well-Known Member
Cool but that is hardly plans built in my opinion? You need molds and stuff don't you?
Why can't building molds be part of a plans biuld? Especially if you can have the plugs for the molds automated and accurately cut by CNC.

#### Nims11

##### Well-Known Member
We're finishing up a two-week Akaflieg where we made wing skins for 24-05 and a horizontal tail for 24-06. We also got a lot of systems work done on 24-03, bodywork on 24-02, and installed the wing main pin bushings in 24-04.
Nice. I nominate Bob to be the lead construction engineer for the project.

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#### SvingenB

Why can't building molds be part of a plans biuld? Especially if you can have the plugs for the molds automated and accurately cut by CNC.
One word: CNC

#### Nims11

Question about CNC routers. The many CNC plans-built on the internet where you can make a 4x8 table for around $2k, are those not accurate enough or good enough for making airplane plugs and molds? #### don january ##### Well-Known Member HBA Supporter Log Member Well call me old school, but wy would I want to put out 2 grand on a cnc then the material to make something with it just to set it back in the corner? I'm sure, to answer your question the cnc you speak of would do a fine job but to me it would take away the joy of some of the build. I guess if you were making alot of parts for resale then good investment. It sucks to build a plug for say a cowling just to look at it when your finished with the cowl and know it's got to go to the pile that keeps growing over in the same corner were the cnc would sit. :ermm: #### FritzW ##### Well-Known Member Log Member Question about CNC routers. The many CNC plans-built on the internet where you can make a 4x8 table for around$2k, are those not accurate enough or good enough for making airplane plugs and molds?
Fortunatly, cost has very little to do with accuracy. How much it cost really depends on what you make it out of and how much work your willing to do yourself. My machine was more than 2K but it was pretty much just "bolt together". I did save a bunch of money by piecing together my own "electronics package".

Short answer: you could easily build a machine for 2K that would do what you want.

#### Riggerrob

##### Well-Known Member
... and see if there is any feedback.[/QUOTE]

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One way to reduce the amount of scrapped molds is to use Rutan's moldless construction methods. Hot-wire cut simple foam shapes like wing blanks, but CNC cut complex-curved foam blocks for complex curved cowlings.
Also look at the flat table lay-up methods developed by American Vision for airplanes and Kelsail's methods for boat-building.
Defintely use vacuum bags to reduce smell and clean up. Ideally use vacuum infusion to almost eliminate toxic fumes.

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#### Autodidact

##### Well-Known Member
Or do the molds and make it a kit. It just occurred to me that molded composite construction is fairly well understood and even sort of "standardized" as far as the methods - maybe that would work in favor of a collaboration instead of against it? Unlike what I said before?

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#### SvingenB

Or do the molds and make it a kit. It just occurred to me that molded composite construction is fairly well understood and even sort of "standardized" as far as the methods - maybe that would work in favor of a collaboration instead of against it? Unlike what I said before?
It doesn't mean it is easy, and do not require practice. Making a non structural part like wheel pants or something is not the same as making a wing. Burt Rutan did not come up with his method for no reasons.

#### Nims11

##### Well-Known Member
One way to reduce the amount of scrapped molds is to use Rutan's moldless construction methods.
Yeah, but then you have all that time consuming and tedious sand and fill finish work to do.

#### Nims11

##### Well-Known Member
It sucks to build a plug for say a cowling just to look at it when your finished with the cowl and know it's got to go to the pile that keeps growing over in the same corner were the cnc would sit. :ermm:
Or do the molds and make it a kit. It just occurred to me that molded composite construction is fairly well understood and even sort of "standardized" as far as the methods - maybe that would work in favor of a collaboration instead of against it? Unlike what I said before?
Right, this is part of what I'm saying. If you have a glass kit that provides the molds that you then resin infuse, you'll have a factory quality glass frame, and for less time than a moldless design. But that mold kit is going to cost a lot. So say you find a group of guys, maybe on a site like this, or wherever, that what to go in together on the kit, so you share the price between the 4 or 5 of you and now instead of paying \$25k you only pay 5 or 6k. You share the molds, one works on part of a wing while the other works on the tail piece, etc. and when your done with that mold you ground ship it to another guy in the group. And here is the great part, when your all done with your builds you sell the whole mold kit on Barnstormers for 80% of what you paid for it. Or for that matter you can buy the kit yourself and then resell it after your done instead of throwing it on that heap of molds your never going to use again. This may sound hokey but it is an actual way to have a relatively fast build, of a higher quality frame, at a much lower cost. Part of what I'm referring to as quality is in the quality control of a mold kit. Compare it with a Rutan moldless where you take some foam, hand shape it, hand layup over it, and then sand and fill for the finish. It seems to me there is more opportunity to muck it up a little that way over a mold design. And correct me if I'm wrong but wouldn't a resin infused mold produce a part that is lighter and stronger than foam sandwich?

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#### Riggerrob

##### Well-Known Member
May I suggest a compromise where you take the best of Rutan's method, the best of CNC, the best of American Vision and the best of Kelsail's methods.
Hot-wire cutting foam blocks is a fast and simple method to create moods for single-curvature components. I prefer Rutan's methods for building flat lifting surfaces.
Meanwhile, CNC cutting foam blocks can simplify the process for cutting moods for complex-curved components like engine cowlings. CNC can eliminate hundreds of hours of hand-sanding and most of the guess-work. The more CNC passes you are willing to pay for, the more precise the moods.
For single-curvature flight surfaces, stick with Rutan's hot-wire cutting method, then vacuum-infuse resin. Vacuum-infusion can eliminate hundreds of hours of sanding, stink and clean-up.

For large, fuselage side panels, start with American Vision's (similar to Kelsail's) method by starting on a large, flat table, lay fibreglass on top of the foam and vacuum-
infuse resin onto the outside of the final skin. Then bend the panels and glass the inside of the fuselage.

The drawing package should include both CNC tool paths and conventional digital drawings, because ever conscientious building will still want to lay a tape measure across CNC-cut foam blocks to confirm that they were cut accurately.
Those CNC tool paths should also include most of the metal pieces and a flat-wrapped Alexander windshield. Flat-wrapping eliminates a dozen production problems inherent in blown or moulded canopies.