# Building Choices

### Help Support HomeBuiltAirplanes.com:

#### etterre

##### Well-Known Member
Sorry of the long post, but I'd really appreciate some advice from those who
have "been there and done that." I really want to build my own airplane for
what are probably all the usual reasons but I can't find a design that I
really like. So I'm currently pondering a one-off design for myself.
But that's a huge commitment and I'd like to be sure that my basic
assumptions are realistic. If they aren't, then I could be expending a lot
of effort for no good reason.

Here are the things I'm trying to balance:
1. Money - I don't have $10,000 USD (or more) to spend just to get started 2. My first child is due next week (and depending on how well that goes, another one could follow in about two years or so...) But if I don't start actively working toward my dream now, then it won't get started until my wife and I are "empty nesters" - and I believe that I would deeply regret that choice. 3. I don't trust most kit companies since I've read about (and seen) too many of them go bankrupt and strand folks with partial kits (or no kit at all). The ones I do trust (Van's, Sonex, and Zenith) don't make anything that really appeals to me. 4. I want a "sightseeing" airplane that allows the pliot and all passengers a good view of...well, everything - the ground below and the sky around me. Comparable to what I imagine you would get from the OV-10 Bronco or OV-1 Mohawk. 5. I'd like to be able to use the airplane for the occasional trip with the family and camping gear. This implies a cruise speed over 120 knots and a cruise endurance of about 5 hours (4 + 1 for reserve) 6. I'd like to make some of those trips to backcountry strips like the ones found in Idaho. This implies a takeoff roll of no more than 1500 feet as well as extra performance to compensate for density altitude. 7. I want to build with composites because: A. Fewer expensive tools to buy B. Riveting is a rather noisy process that could alienate the family C. Doesn't require recovering every few years like tube and fabric. D. Holds up well over time - doesn't rot or corrode - doesn't dent easily E. I can see myself building molds, doing layups, and obsessing about sanding. But I can't see myself welding a fuselage together or assembling wooden ribs for seemingly endless months. F. Finished result just looks better to me So I doodled on a few napkins and the picture that pops out has a 4 seat (+ bags) fuselage like the Prescott Pusher but has twin tail booms like Vulcan's ION (http://www.vulcanaviation.com) instead of the Prescott's T-tail. Yes, I realize that a pusher has FOD problems but everything is a compromise. I won't subject you folks to my lousy artistic abilities. If I was going to provide a decent picture of it, I'd need to start putting together CAD drawings - but then I would really get attached to the design... So here's where I'd like some help. Designing a new airplane isn't even close to being easy and I've made it significantly harder by trying to design something different. But, after pondering a bit, I've noticed that there are a few of my requirements that add just a little more functionality but drive a lot of the difficulty. For example, if I compromise on forward/upward visibility, then I'm probably designing an all-composite, high wing, tractor without wing struts. If I compromise again and move away from 100% composite, then I'm no longer designing - I'm building a BD-4 So where do you think I could simplify things? Here are the ones I've got targeted (please add your own): Is it realistic to think that the airplane would be usable for the "family vacation?" How many of you have taken a mom+dad+kids trip in your own (or a rental) airplane? How did it go? Would you do it again if you could? Of those that haven't done it, how many would want to take a trip like that? This is easily the highest cost assumption for me that may yield the least benefit - maybe 1 or 2 trips a year for 10-15 years (If I'm really optimistic on build timelines and family interest) Any ideas on how I could reasonably compare the view from one plane to another? Is it "safe" to assume that the forward visibility from a BD-4/Tailwind/Bearhawk is going to be similar to a 172? Sightseeing/visibilty is a big consideration for me. If it wasn't, then I'd probably have a set of plans ordered by now... :whistle: Any rebuttals on my material choice? I've thought about going to some of the SportAir workshops to "get over" my aversion to tube/fabric, but spending  to do something I don't think I'll enjoy seems downright silly. Am I unreasonably throwing out the kit designs? The GlaStar planes could be a good compromise fallback for me from an aesthetic and performance standpoint. BUT the possibilty of being stuck with wings, a tail, and a bankrupt company frightens the heck out of me. Why? At any point short of having the whole kit, I don't necessarily have all the parts, information, or even legal license to finish my plane. Why? Well, you never get a a real set of plans that specify everything (I'd love to be wrong on that one) - so I don't have the information (or perhaps even the legal right) to manufacture the things I don't have (short of redesigning them). And now I'm stuck in a corner I don't like: I have to accept the compromises of the original design while still doing a big chunk of design work on my own. If I had the wad of cash to buy the whole kit upfront, then those problems go away. So...how easy is it to find partially completed kits? What sort of discount should I expect? Where would I look? I've seen them on e-bay before, but I often wonder about how many tasks are completed and if all the parts are really there... Last one up is more about the process of design. Please poke holes here if I've missed the point - the core problem seems similar to what I see in software every day but I want to make sure I've got it right. I've seen it stated many times that "if you make a change like that, you may as well re-design the entire airplane." This is mostly because airplane design is a tightly coupled process - each choice you make affects some other point of the design. One of the "easy outs" I considered earlier was to buy a set of plans for a BD-4/Tailwind/Bearhawk then dive in and analyze the structure to figure out what kind of loads I need to design my replacement composite structure for. After a whole bunch of "extra" work in re-design and build, I finally have a plane built out of graphite, fiberglass, and epoxy. Here's the problem: I've done a whole bunch of work, but I haven't really produced anything better than the original. It's probably heavier, harder (overall) to build, and it isn't more aerodynamically efficient. Why? Well, I carried forward all of the compromises that the original designer made and then added some of my own on top. For example, designer A picked airfoil B because they were using a wood spar and needed a thickness of y to get a spar that would carry the loads. But I, sadly enough, used a fiberglass spar of a similar physical size so that I would still be using airfoil B, even though that means my spar is bigger than it needs to be. And I have to do extra work to make sure that I haven't created new point loads. And I have locked myself out of (perhaps) choosing a different airfoil that would give me better performance while providing a thickness that is closer to "optimal" for the construction method that I've chosen. Thanks for actually reading all of this. PS - to those who think that the name or requirements might sound familiar: Yes, I am the same etterre from the canard aviation forum. I have, however, decided that benefits of having flaps are probably greater than the benefits of having a canard. Sorry about that... Last edited: #### wsimpso1 ##### Super Moderator Staff member Log Member Oh man, you cover a lot of ground... Composites do tend to benefit high speed airplanes more than slow planes. The reason is that composites tend to make a less draggy airplane at the cost of a little more weight for the same payload. While they tend to be tough, you can not really bang any airplane around much. Rag-and-tube construction does tend to benefit slow, lightly wing-loaded birds. The drag is relatively unimportant and loadings are small, and it tends to be light. And they do not need covering every few years if they are hangared - more like 20 years for modern coverings. Next, I do not know of anyone selling plans for decent scratch built fiberglass birds except the Long EZ derivitives (AeroCanard, Velocity, Cozy, etc) And they don't exactly fit the bill for moving four people and bags and do it while sight-seeing and going slowly. I am building from scratch in fiberglass for a reason - I wanted a fast roomy two seater with good baggage room and I wanted to build in fiberglass. I already had experience with it and enjoy it. So I am, but there was not much out there to pick from, every process has to be thought thtrough by yours truely, and it is taking time. What you described actually seemed more like the a C182. Aluminum has a lot of benfits. Cessna 182's and 206's are used a lot around the world for a reason. Roomy, lots of load carrying capability, able to operate out of relativel small places. A C172 might do while the kids are small. All of this says C152 to learn in and stay happy day to day, and a C172 for trips until the kids get bigger. There is an expression in boating "If you want to sail, buy a boat" It is used when a person expresses interest in building a boat. Building is a long term hobby. So how to fly while you play with fiberglass? For you, I would recommend finding a club that has Cessnas. There is one on my field with C152's, a C172, and a C182. Covers the whole Gamut. I learned to fly there. Then became a co-owner of a Cherokee. Building is a hobby that may take many years. Enjoy the build. Billski #### Nilsen ##### Well-Known Member Nice posting. You've come to the right place. I came here with the same what do I do, and how do I do it in my head; still have it too. These boards are great for getting opinions. I learned a lot from the composite practice kit from Aircraft Spruce. It's a must if you are thinking of using composites in aircraft construction. Even if you've used glass/epoxy systems in other sorts of things the 'kit' covers the way to do it to make aircraft. I second Billski, I've been hanging out around gliders a lot these days and I can say there are a lot of old wood and fabric birds that are doing just fine with 20 years of the same old skin, but they do have to be hangered. Then again so do the modern fiberglass ships. #### orion ##### Well-Known Member That's quite a list, and all your questions are valid. The problem though is that the answers may not be so straight forward or easy. But let me jump in a give you a few cents worth of my opinions. The want of a unique airplane is certainly not new, especially given the somewhat limited range of the airframe marketplace. But the decision to start from scratch is really a function of how flexible your requirements may be. After all, as Billski pointed out, relax on a few issues here or there and your needs might be easily met by any number of certified airframes or even one or two kits (one that wasn't mentioned above but that could certainly be a candidate for you is one of the Murphy airplanes - very capable airplanes, durable, well engineered and a reputable company). Going from scratch is quite an endeavor, especially if you're planning on working with composites. Since my business is designing and prototyping custom aircraft for customers, I certainly would not want to dissuade you from that path, but at the same time I would not want to encourage you only for you to get hit by the reality of the process as you get entrenched in the tasks associated with making laminate parts. There are many (many, many, many, etc.) who have started down this path only to have to delay or give up some time down the road and end up with a shop full of expensive but essentially worthless unfinished parts. So, on to your list: 1) It actually wont take$10k to get started in this process but you can pretty much figure on at least $5k to$6k. That can pretty much configure the airplane, including the necessary performance, stability and control analysis to back up the design. In our case (www.oriontechnologies.net), we divide up the design process into several phases so that customers can proceed at their own phase. I've had some projects where the design evolution has stretched out over as much as six or seven years.

2) Congratulation on your first child - the sleepless nights those first couple of years may make it difficult to concetrate on your project, especially when coupled with the other aspects of life, like your job. But you're right in wanting to get started - it is very easy to delay this kind of thing, sometimes to the point where it never gets done.

3) Finding a good kit company just requires a good amount of research. Yes, many have come and gone and in this business more than others, there are really no guarantees unless you dive in feet first and just purchase the whole kit outright.

4) Most high wing airplanes will allow you to get the view you're after. It's the other variables that will probably count more. True, the view isn't as spectacular as from a specially designed observation aircraft, but most will come close.

5) The idea of taking one's familiy one a flying/camping/sightseeing vacationis a common goal but here you must really be sure that your family has the same interest. Does your wife rally like small airplanes? Is she willing to spend that amount of time in a rather small and noisy environment?

By the way, yes it's nice to get that kind of range but realistically, most people don't have bladders that big. Figure that you'd be doing maybe two hour leggs on your travels.

6) This requires a relatively durable airplane with sufficient power to account for the density altitude and the less than benevolent gusts of wind. The power requirement is especially important as you consider your budget.

7) Most of your reasons are valid except maybe for (A) and maybe (B). While it is true that you may not need as expensive a tool set for working with the materials, your actual cost (time and money) will be in the tools you'll need for forming the various parts (plugs, molds, etc.). In essence, doing it right (by the use of molds) will require you to expend about the same effort as building about two and a half airplanes. The results are worth it but just be sure you're ready for that commitment.

Regarding noise, while it is true you won't be riveting much, if at all, you will be doing a lot of sanding. The most reasonable way to do this is with a really good air compressor and several air tools. these are by no means quiet.

Then, when it comes to annoying your family, the dust and some of the smells may certainly do just that. Again, I don't mean to dissuade you - I guess my point is for you to be realistic in the evaluation of this process.

Now to answer your questions: Yes, it can be realistic to take your family on camping and/or vacation trips. But take short trips first to make sure you enjoy it. Maybe rent an airplane first before jumping into all this. Also, if you're flying into back-coutry strips, make sure you're very proficient in back-coutry and mountain flying.

But in the same time also be realistic about your other life commitments. It may be that you wont be taking as many of these trips as you think. But only you can answer that one.

Personally, I've taken a couple of extended trips with my wife, including some camping. We use our airplane almost weekly (in addition to my work uses) to get to our island property, usually packing our gear and our two rather sizeable dogs. For us, our airplane is essentially the family station wagon (a very expensive one but one that is very enjoyable, usable, and practical) that enables us to make the trips in a fraction of the time it would require by car.

Regarding visibility, the view from most of the airpanes you mention is about the same. Some can come with observation windows, even clear doors. But overall they are similar. Again, also look at the Murphys before deciding on a custom.

Regarding your questions about the design process, that could be a lengthy dissertation - maybe for that you can call me directly and we can talk "airplane" for a bit so I can give you at least an outline. And no, taking an existing design like a Bearhawk and changing it to composite is not realistic. While the loads can be derived, the new materials have to be treated as virtually a new structure so form the structural design aspect, the tasks are still as for a new airplane. Besides, why build from composites a structure that is comprised of slab sides - for that you might as well buy an Aerocomp (although I wouln't recommend it).

#### CAB

##### Well-Known Member
A trend I see more and more of is the plans/kit (P/K) approach. Buy the plans and then any kits or components you wish! Company goes broke- so what- I can make the parts!:ban: The BD-4 and Bearhawk have both been mentioned several times in this thread; both are P/K planes.

CAB
Bearhawk#862

#### etterre

##### Well-Known Member
Thanks for the responses!

I meant to reply a little sooner, but Emily decided to be born on 10/7. She's very cute - the nurses even described her as a "Gerber baby." Mom and baby are doing fine, if a little sleep deprived. Having (for the moment) nearly caught back up on my sleep, I was going to reply this past weekend - but then my DSL broke.

I know that I'm all over the place on requirements. This may be a bad habit of my software design background - I typically get all the "wish list" ideas and hard requirements at the start (so you start off with a supersonic aerobatic 4-seat plane that absolutely has to land in 500 feet) and assign cost and "usefulness" numbers to each feature. Then you start killing the features that cost too much and aren't very useful... As much as I'd really like to start "doing something," I think my time is probably better spent on nailing down my requirements.

I think my current plan is
1. Finish my sport pilot ticket. I've been at it since March, and I have a little less than 20 hours of dual to show for it. The weather and airplane-scheduling gods have not been kind to me. out:
2. I've wanted to take the wife up with me ever since I started training. It's always seemed like a good idea, but now it looks more like a necessity in order to figure out if cross-country flight is even in the picture. Getting the right conditions might require sacrifices to the weather and scheduling gods, though.
3. Build a cabin mockup - nothing fancy - just cheap plywood or cardboard plus maybe some car seats from a junkyard. This will help me find out if I really can get the sort of view that I think I can.
4. Get some dual time in a C-172 so I can compare it to the Luscombe 8A that I've been flying.
5. Start building some composite "practice items" - I'm thinking about either a kayak or a canoe. I've done some R/C stuff before, but building something bigger could be a good learning experience. The wife and I do go canoeing on occasion, so a canoe might make more sense even if it isn't as curvy/challenging.

That ought to be sufficient to keep me busy throughout the winter...

#### etterre

##### Well-Known Member
Originally posted by wsimpso1
Rag-and-tube construction does tend to benefit slow, lightly wing-loaded birds. The drag is relatively unimportant and loadings are small, and it tends to be light. And they do not need covering every few years if they are hangared - more like 20 years for modern coverings.
Hmm, 20 years on a single covering? That makes tube/rag look a lot better. I was anticipating about 5 years between coverings.

Originally posted by wsimpso1
What you described actually seemed more like the a C182. Aluminum has a lot of benfits. Cessna 182's and 206's are used a lot around the world for a reason. Roomy, lots of load carrying capability, able to operate out of relativel small places. A C172 might do while the kids are small.

All of this says C152 to learn in and stay happy day to day, and a C172 for trips until the kids get bigger.
After looking up some numbers, yes the C-182 does look like it would do pretty much everything I want - if I can get over my obsession with a "better" view. I don't think I could swing owning one all by myself - unless I bought a basket case and restored it. But then I'm probably not any farther ahead (time, money, and performance wise) than if I had built a Bearhawk from scratch.

Originally posted by wsimpso1
There is an expression in boating "If you want to sail, buy a boat" It is used when a person expresses interest in building a boat. Building is a long term hobby. So how to fly while you play with fiberglass?

For you, I would recommend finding a club that has Cessnas. There is one on my field with C152's, a C172, and a C182. Covers the whole Gamut. I learned to fly there. Then became a co-owner of a Cherokee.

Building is a hobby that may take many years. Enjoy the build.
I'm greedy - I want to build and fly. :gig:

The idea of joining a flying club with multiple planes sure sounds a lot better than my previous plan of renting for the foreseeable future. The only problem is that I haven't seen evidence of a flying club that I could join in the St. Louis area. I have seen ads for single-plane partnerships but that seems a bit more problematic due to entry costs and scheduling conflicts. The only St. Louis club that I'm aware of is Boeing's employee club - with a single C-172 (but since I'm not a Boeing employee... ) I obviously need to do some more asking around on this one...

#### wsimpso1

##### Super Moderator
Staff member
Log Member
Um, don't build a boat. Really. They are harder than you think and do not mimic an airplane as well as you might hope.

I would recommend building the practice parts in this little kit from Aircraft Spruce - part number is CK and it costs $95 including epoxy - and it has all of the materials you will need to make several important parts as they are made for the Rutan Aircraft Factory birds. It is an excellent review of the methods you will encounter in building composite airplanes. http://www.wicksaircraft.com/catalog/product_cat.php/subid=2224/index.html If you still love fiberglass after that, go for an airplane. If you decided to go with metal, many kit makers have a rudder kit for you to try out. As far as building in fiberglas, I recommend a shop seperated from the house - It keeps a lot of the dust and wet epoxy and smells out of the living area. If you use an attached garage, even with a breezeway, the dirt and the smells will find the house. Billski #### Rhino ##### Well-Known Member Contact an EAA chapter and visit a fly-in or airshow where you can see, and often sit in, many of the possible choices. http://www.flyins.com #### etterre ##### Well-Known Member Originally posted by orion 1) It actually wont take$10k to get started in this process but you can pretty much figure on at least $5k to$6k. That can pretty much configure the airplane, including the necessary performance, stability and control analysis to back up the design. In our case (www.oriontechnologies.net), we divide up the design process into several phases so that customers can proceed at their own phase. I've had some projects where the design evolution has stretched out over as much as six or seven years.
Hmm, when I wrote it down, my money criteria was more about "Why I can't afford brand X kit." I know that when I add the engine, prop, and avionics, I'll leap well over $10k - but since I won't need those for a while I should be able to "save up" for them over the 5+ years of building. It really hadn't occurred to me that I could hire someone else to do the engineering (or even afford to do so). If I do go down the "unique design" road, then$5k-\$6k sounds a lot more attractive than the 5-10 years of part-time design/engineer/test tasks that I was imagining...
Originally posted by orion
5) The idea of taking one's familiy one a flying/camping/sightseeing vacationis a common goal but here you must really be sure that your family has the same interest. Does your wife rally like small airplanes? Is she willing to spend that amount of time in a rather small and noisy environment?
Point taken and already obsessively worried over. My wife seems open to the idea at the current time and some of her comments lead me to believe that cross-country trips, in her mind, represent the "value" portion of my hobby.
Originally posted by orion
By the way, yes it's nice to get that kind of range but realistically, most people don't have bladders that big. Figure that you'd be doing maybe two hour leggs on your travels.
True, but those number put OSH in the safe "one-hop" range from where I live. I also remember that one of my father's favorite tricks for family car vacations was to wake everybody at 5 am and pile us in the car. We'd all immediately go back to sleep and he would have to stop until about 9 or 10 am when we started waking up...
Originally posted by orion
7) Most of your reasons are valid except maybe for (A) and maybe (B). While it is true that you may not need as expensive a tool set for working with the materials, your actual cost (time and money) will be in the tools you'll need for forming the various parts (plugs, molds, etc.). In essence, doing it right (by the use of molds) will require you to expend about the same effort as building about two and a half airplanes. The results are worth it but just be sure you're ready for that commitment.
True newbie question - no offense intended: I can see where molds give you a repeatable part. I can also see that using molds could (as compared to Rutan-esque moldless construction) give you a more accurate part. But isn't the sort of error you get with moldless construction "only" about 1-2 plies in thickness? Cory Bird's "Symmetry" seems to be an example of how you can get extreme accuracy without molds (unless I'm terribly mistaken about how he built it). So what makes using molds the better method? Or does it really come down to how much slop (in terms of accuracy and also excess weight from filler) that the builder can tolerate? Perhaps I should move this to a new thread in the Composites forum...
Originally posted by orion
Regarding noise, while it is true you won't be riveting much, if at all, you will be doing a lot of sanding. The most reasonable way to do this is with a really good air compressor and several air tools. these are by no means quiet.

Then, when it comes to annoying your family, the dust and some of the smells may certainly do just that. Again, I don't mean to dissuade you - I guess my point is for you to be realistic in the evaluation of this process.
No problem, realistic opinions are exactly what I wanted. Since I'm probably going to be doing my building in a detached garage that's about 15 feet from the house, some noise and stench are probably acceptable. I actually live in the city of St. Louis, so I've toyed with the idea of renting some of the vacant warehouse space that's only a 5-10 minute bike ride away. It's probably more $$than I can (or want) to spend, but I haven't priced it out yet... Originally posted by orion Now to answer your questions: Yes, it can be realistic to take your family on camping and/or vacation trips. But take short trips first to make sure you enjoy it. Maybe rent an airplane first before jumping into all this. Also, if you're flying into back-coutry strips, make sure you're very proficient in back-coutry and mountain flying. But in the same time also be realistic about your other life commitments. It may be that you wont be taking as many of these trips as you think. But only you can answer that one. This is the really difficult requirement in a lot of ways. If I keep it, then the airplane can be sold to the wife as a tool. If I drop it, then it's just my toy. The "short test trip" idea strikes me as a very good one - and I even have 3 perfect destinations since my 3 brothers are within a decent distance for this (300-900 miles). Since we already do the tent camping thing (we've even gone backpack camping in the Grand Canyon), that part of the assumption behind the requirement is pretty safe. The unknown is the practicality of using a small airplane to get from here to there. As for the extra training - IFR ticket and backcountry training are (for me) a must before doing a trip like that - but if I don't build the capability into my airplane, then I'll never take the trip. Originally posted by orion Regarding visibility, the view from most of the airpanes you mention is about the same. Some can come with observation windows, even clear doors. But overall they are similar. Again, also look at the Murphys before deciding on a custom. Hmm, looked at their site (www.murphyair.com right?) - It looks like my choices are currently limited to the Moose or a 2-place model. The Moose seems a little bigger and thirstier than I really want to tackle. Something that can be fairly compared to a DeHavilland Beaver or a Cessna Caravan offers way more capability than I need (at least until kid #4 arrives ) The details were pretty thin on the "Yukon" - is it meant to be something in between? Originally posted by orion Regarding your questions about the design process, that could be a lengthy dissertation - maybe for that you can call me directly and we can talk "airplane" for a bit so I can give you at least an outline. I might take you up on that at a later date if/when I actually want to get started on a new design. Hopefully I can convince myself that existing designs are more than just "good enough." Originally posted by orion And no, taking an existing design like a Bearhawk and changing it to composite is not realistic. While the loads can be derived, the new materials have to be treated as virtually a new structure so form the structural design aspect, the tasks are still as for a new airplane. Besides, why build from composites a structure that is comprised of slab sides - for that you might as well buy an Aerocomp (although I wouln't recommend it).[/B] In retrospect, that "question" was rather poorly phrased. I really only wanted confirmation that the central problem is due to the tight coupling between all the points of the design. The rest of the rambling was my very poor attempt at explaining how different aspects are tied together without writing a 10-page explanation of how many other things I'd need to "fix". I'd already abandoned the concept really thinking through all the things that change. In a past life, I studied to be a ceramic engineer...then I found out what sort of job and pay a ceramic engineer with only a BS could get...and how much more I could make as a "Computer Scientist" (much easier job). In hindsight, that was a bad decision - but without it some other good things would never have happened... Still wishing.... #### etterre ##### Well-Known Member Originally posted by wsimpso1 Um, don't build a boat. Really. They are harder than you think and do not mimic an airplane as well as you might hope. How so? I was envisioning building a canoe using the same techniques that are used in building a Cozy fuselage. Granted, the only plans/kits I've seen so far use completely different methods but I was hoping to play "mad scientist" on something "simple" - and then get harshly schooled on why it isn't simple. :roll: Originally posted by wsimpso1 I would recommend building the practice parts in this little kit from Aircraft Spruce - part number is CK and it costs 95 including epoxy - and it has all of the materials you will need to make several important parts as they are made for the Rutan Aircraft Factory birds. It is an excellent review of the methods you will encounter in building composite airplanes. http://www.wicksaircraft.com/catalog/product_cat.php/subid=2224/index.html [/B] Any difference between the Wick's kit and the aircraft Spruce kit? http://www.aircraftspruce.com/catalog/cmpages/practicekit.php I can drive to Wick's (so that saves me shipping), but the A/S kit is about 50 cheaper (without shipping). #### orion ##### Well-Known Member Our answers here seem to be getting longer and longer - so I'll try to be brief. First and formeost, I just want to clarify the issues of airplane design costs. There are many steps in the airplane design process, each with a multitude of variables which are somewhat difficult to nail down in the very early stages of this type of discussion. The figure I posted above will get you started but certainly does not represent the total cost (and effort) of designing the entire airplane. The figure covers the first phase, which typically defines the outer shape (loft) of the airplane, as well as analyzes its performance, stability and control, and defines a preliminary weight and balance estimate. At the end of this first step you will know what the airplane will look like, how much it can carry and how far and how fast it can go. This includes not only cruise speed but also take-off and climb, spin resistance, loading envelope, etc. This is followed by the structural design phase, which defines the structural configuration, derives the anticipated loads, and analyzes the structure in order to arrive at the necessary material gauges and/or laminate schedules. For composites the analysis is done through finite element methods where the airplane is broken down into its basic structural components, which are then modeled, loaded and analyzed. It can take anywhere from four to six (on average) distinct models to analyze a typical small airplane, plus any additional models as needed to define things like spar attachments or carrythrough structures, landing gear attachment, engine mounting hard-points, etc. The cost of each of these models depends on complexity, materials, loading conditions, etc. If I were to guess at an average I think it would range in the 4,500 to 7,500 ballpark for each. Once the structure is known, you can then proceed to the detail design, where you now define all the specifics of the airplane. This includes everything from designing all the parts, to designing the tools and fixtures necessary for the parts' fabrication and assembly. This also includes all the components that go on the inside, ranging from the controls to the fuel system, as well as the interior furnishings. This phase has no set cost since it does cover a wide gamut of variables, one of which is the customer's experience. If the customer has built airplanes before, he (or she) may not need all the details since he is already familiar with what needs to go on the inside. Others though need to see everything down to the last nut and bolt. On the high side, this phase can be very time consuming and thust the costs can come in as high as two, or more, times all the previous work, combined. So, what this means is that the design process can be quite involved and yes, expensive. This is where you need to figure out whether a unique airplane is really what your'e after or whether you think you might be just fine with a kit. The other issue to contend with is the one where you consider designing your own. This is a difficult subject to give advice on since I don't know you nor your background or tenacity. Most that go down this road find out very quickly how involved process this can be and often times, the more research you do, the more you find out how much you don't know. Early in my career it was not uncommon to discover something months down the road that I missed in the first part of the process, ofen requiring a significant amount of rework. And this is even after I was educated and trained specifically for this field. So the bottom line in all this has really to do with your own preferences and judgement of your own abilities. I know a lot of folks who after sitting down and going through all the variables and costs of doing their own, discovered that the kits wern't all that bad. And of course the other option is to just bite the bullet and buy a used ceretified airframe. Yes, it'll cost more than buying a kit but in the long run, depending on your choice of airframe, it may actually be less expensive by the time you finish the build, and of course you can use the airplane right away. Regarding molded construction, the real benefit of building the extra tooling is not only accuracy (assuming the plug you took the mold off of is accurate) but also part integrity, quality, finish and weight. You can control the laminating process to a much higher degree in a mold than through building over foam so the results tend to be dramatically better. You can also make several parts so if you ever though you might want to make a couple of the airframes (and sell one to recover some costs), it's certainly possible if you have the tools. But it is a lot of work so here you must cosider the trade-offs. As far as selling an airplane to your wife is concerned, that may be the toughest task. However, if you can demostrate the benefits and truly present it as a tool or as the really fast family station wagon, then it might be a bit easier to do. If it turns out both of you enjoy it, then the sell is much easier to do. And finally, regarding size - you mentioned the issue of some of the Myrphys being too big. Don't underestimate your needs. Virtually everyone I know that owns an airplane has either upgraded or initially bought bigger than they thought they needed in order to get the most use out of the aircraft. It's a very common accurance when a pilot realizes that one size up would have been more ideal than what he initially bought. In your case, your wife, one or two kids and camping gear can add up quite quickly. Add a dog (two in our case) and the "roomy" airplane can suddently become cramped and not capable of what you envision it for. One of the most critical things to keep in mind is not to use fuel consumption as the criteria for airplane selection (this took me some time to learn). Fuel is the cheapest part of flying and if your engine limits you in where you want to go or how fast you can get there, then the airplane is no longer as useful as you initially thought. This is especially the case if you're serious about back-country and/or mountain flying - no such thing as too much power. Using ourselves as an example, my first airplane was bought with economy in mind - a Grumman AA1C Lynx with a 125 hp O-235. It was fun and somwhat useful for my wife and me (for short hops) but with us and full fuel we were at gross. No room for baggage and with our dog in the back we were actually over gross (not to mention it being very ackward getting our 65 pound dog back there). Currently we own a Cherokee Pathfinder, which is essentially a four seat Archer or Arrow airframe but with an O-540 on the nose and a 1,500 pound payload. The Pathfinder is Piper's answer to the Cessna 180 or 185 so it makes a good hauler with decent volume and a pretty good range (85 gallons on board), although it's not as fast as I'd like. But with our two dogs in there (the second dog is about 110 pounds - we fly it with only two seats installed) there remains only minimal room for a duffel bag or a small bit of gear. In hind sight, a Cherokee Six or Saratoga would have been much better, but I didn't think we'd need something that large. I think in about a year or two we'll need to upgrade. Oh well, such are toys - err, I mean station wagons. #### etterre ##### Well-Known Member Originally posted by orion Our answers here seem to be getting longer and longer - so I'll try to be brief. Totally my fault - I've asked too many different questions in one thread. I'll try to limit myself to one question per thread in the future. Many thanks for laying out a thumbnail sketch of the design/engineering costs - the cost (and time) numbers now sound a lot closer to (and probably a little higher than) what I originally expected. Having a realistic idea of how much effort and$$ it will take to get from a sketch on a napkin to finishing the test flight hours really helps assign a cost to the unique features that I want. It's not really the cost of my time or effort that's going to keep me from doing it - thinking and "puttering in the workshop" are both leisure activities for me. But maybe there's a bigger "fun quotient" to some other activity - playing with Emily, maybe? As long as I'm enjoying the time I spend on the project and I can balance it with my other commitments then I figure I'm doing okay - even if I never finish it.

As for size concerns - after looking at the Moose again, I realized that it is in the size range that I'm probably looking at. For some reason, my mind connected the Cessna 206 to the Cessna Caravan.

#### Allsurf

##### New Member
Composite Aircraft

Have you looked at Vision Aircraft? It might be something that would interest you. They are coming out with a 4 seater built with carbon fiber composites, et al.

Allsurf
Houston, TX

#### wsimpso1

##### Super Moderator
Staff member
Log Member
I was trying to help you get experience with a couple types of construction, because you have to like the medium or you will never finish the thing. You did not indicate experience (maybe I missed it) in any of the materials up for consideration, so I was concerned about that.

I recommended the fiberglass practice kit and the book by Rutan as a way to find out if you like fiberglass. Most canoes and kayak plans out there are for building "strip" canoes, which are wooden boats with a skin of fiberglass - not eactly what you want to do in an airplane. The rest pretty well require making a plug and a mold... Either way, building a canoe is a substantial task, and if you do not love working in the stuff, well, you find out too late. Trust me a little on this, it is way bigger than you think.

The kit and book really give you an education and will help you decide. So does a metal rudder kit... Hanging out with an EAA chapter and offering to help on everybody's project can get you a sample of experience too.

Try some internet searching to find a flying club. They do not tend to be highly advertised...

Billski

#### etterre

##### Well-Known Member
Re: Composite Aircraft

Originally posted by Allsurf
Have you looked at Vision Aircraft? It might be something that would interest you. They are coming out with a 4 seater built with carbon fiber composites, et al.

Allsurf
Houston, TX
Last time I checked, the Vision was a 2-seater with a low wing, which doesn't allow for much visibility in the downward direction. I have seen web pages of folks building a stretched 4-place version - but I'm not aware of any completions.

#### etterre

##### Well-Known Member
Originally posted by wsimpso1
I was trying to help you get experience with a couple types of construction, because you have to like the medium or you will never finish the thing. You did not indicate experience (maybe I missed it) in any of the materials up for consideration, so I was concerned about that.
I've got a little experience with balsa and composites through R/C modeling and home projects, but nothing approaching 100 hours. So no, I'm definitely lacking experience.

I recommended the fiberglass practice kit and the book by Rutan as a way to find out if you like fiberglass. Most canoes and kayak plans out there are for building "strip" canoes, which are wooden boats with a skin of fiberglass - not eactly what you want to do in an airplane. The rest pretty well require making a plug and a mold... Either way, building a canoe is a substantial task, and if you do not love working in the stuff, well, you find out too late. Trust me a little on this, it is way bigger than you think.

The kit and book really give you an education and will help you decide. So does a metal rudder kit... Hanging out with an EAA chapter and offering to help on everybody's project can get you a sample of experience too.
I have considered doing Zenith's "build a rudder" class since they're pretty close to me - I should probably put that on my list after the Rutan practice kit. On the other hand, EAA chapter 32 has (or at least used to have) a Mustang project that might be more educational.

Try some internet searching to find a flying club. They do not tend to be highly advertised...

Billski
Yeah, Google isn't being very helpful - I'm probably going to try visiting the fields in my area and seeing if I can get lucky... I'm guessing that the FBO's aren't going to be overly helpful, but maybe the corkboards or a lucky encounter will yield something.

#### Nilsen

##### Well-Known Member
I had a lot of luck with these guys,

http://www.bluebound.com

It's organized by State then each State has sub sections for Flying, Skydiving, Soaring, Hang gliding ... etc.

Many of the listings are very grass roots/low tech. Your profile says you are from Missouri I just checked and there was 2 pages of flying links, I'll bet there's a club in there somewhere.

Looks like your getting all the help you need on materials but I bought the Rutan kit from aircraft-spruce and it's worth every penny. The book alone is worth the price of the whole package.