Comprehensive mods list

[Jon Matcho]

Well here's an old post to get the ball rolling. This was directed more at the Long-EZ crowd.

(Emailed list follows in original post)

 

Now that is what I'm talking about.

TMann, I just read through the email/list you quoted. It's obviously from JD @ Infinity. There's some good stuff in there, but I would caution anyone using that as a reference -- the Infinity 1 aircraft/project hasn't flown yet, so it doesn't matter (to me at least) what its benefits are until it actually flies and is taken through a full suite of flight tests.

[TMann]

(Emailed list follows in original post)

 

TMann, I just read through the email/list you quoted. It's obviously from JD @ Infinity. There's some good stuff in there, but I would caution anyone using that as a reference -- the Infinity 1 aircraft/project hasn't flown yet, so it doesn't matter (to me at least) what its benefits are until it actually flies and is taken through a full suite of flight tests.

 

He has a prototype flying and is working on will be the production version.

Is it flying?

Does it fly?

Will it ever make it to production?

I don't much care. It's a list of Ideas that builders have come up with that someone formulated into a list.

Are they all JD's Ideas ......... no.

 

It's no different than reading what other builders are doing. I could name a ton of Ideas people have come up with and posted.

 

Again, it's just a list.

Many of these Ideas are already flying. The Ideas do not have a dependancy on one man's project.

[Jon Matcho]

I know, I'm with you, and was only saying that particular list is somewhat biased towards http://www.infinityaerospace.com.

 

I am interested in looking into what this is all about:

 

don't install foam wedges in front of center section spar in strakes -- that's where the retracts go. If no retracts, still don't do it

"To infinity, and beyond!"

[TMann]

 

"To infinity, and beyond!"

That's the 'Buzz'

[egalvan]

http://www.maddyhome.com/canardpages/pages/chasingmars/Chapter04/2007-04-20.pdf

(!)

 

Excellent PDF, where can I find more of them? I'm not able to find your web site at maddy's...

 

Thank you

 

ErnestG

[chasingmars]

where can I find more of them?

http://www.maddyhome.com/canardpages/pages/chasingmars/index.html

 

I'm not quite up to date, I have some I haven't posted yet, and some I still need to write. I'm glad you found it interesting.

[rsrguy3]

So, Marc,

I'm guessing you work or have worked for Scaled? So here are my quandries at this point. 1. I am comfortable with the bag, and will accept the expense of it for a reduction in sanding, even though I am quite adept at it. Comments on my rational please.

2. I fully expect to do some hand lay-ups, but, in your experience have you actually had two of the same part built and tested utilizing both methods? what are the differences/advantages/disadvantages? Most people think in terms of weight, but I'm more concerned with issues surrounding long term resistance to delam and minmizing surface irregularities, (reduction in trapped air, a plus)

3. How am I to determine the use of carbon in by build, both as a weight reducer/strengthener? (how much and where?)

 

-Guy

[Marc Zeitlin]

So, Marc, I'm guessing you work or have worked for Scaled?

I work for Scaled now.

 

1. I am comfortable with the bag, and will accept the expense of it for a reduction in sanding, even though I am quite adept at it. Comments on my rational please.

There is no rationale. For non-molded parts, there will be zero reduction in sanding/finishing. Bagging is an attempt to save weight and supposedly get more repeatable, slightly stronger parts. The first is suspect, or minimal at best, and the second is unnecessary, if even possible.

 

2. I fully expect to do some hand lay-ups, but, in your experience have you actually had two of the same part built and tested utilizing both methods?

Sure.

 

what are the differences/advantages/disadvantages?

For MOLDED parts, bagging will provide lighter and stronger parts that require less finishing, IF DONE CORRECTLY. If done incorrectly, the parts will be weaker.

 

Most people think in terms of weight, but I'm more concerned with issues surrounding long term resistance to delam and minmizing surface irregularities, (reduction in trapped air, a plus)

Sigh. Since neither of these things is an issue in building a structurally sound aircraft per plans, I'm truly at a loss in trying to understand the fixation/fascination that some folks have with vacuum bagging. Let me make this absolutely clear:

 

NO RUTAN DERIVATIVE CANARD COMPOSITE AIRCRAFT HAS ___EVER___ HAD A STRUCTURAL FAILURE WHEN BUILT TO THE PLANS. EVER. EVER.

 

And yes, I'm shouting.

 

No structural or cosmetic problem that canard composite aircraft HAVE had would have been prevented by using vacuum bagging correctly (and "correctly" is important).

 

Is vacuum bagging good? Yes. Is carbon good? Yes. Almost all of Scaled's aircraft are built mostly from carbon and are mostly bagged. But moldless composite construction using fiberglass is NOT the same methodology. You're NOT using molds. You're NOT using carbon. What makes folks think that they need to vacuum bag?

 

3. How am I to determine the use of carbon in by build, both as a weight reducer/strengthener? (how much and where?)

Since the COZY MKIV plans don't call for carbon anywhere, you don't need to determine anything. If you're an aeronautical/mechanical engineer with knowledge and/or experience in composite design, then you can analyze the structures and determine material needs. If not, you can spend 4 years in engineering school and then a few in industry learning the skills necessary to "determine the use of carbon". Or hire someone with the skills to determine the usage for you. For what reason, I don't know, however.

 

As stated, an increase in strength is not necessary - these planes DON'T fail. As far as weight reduction is concerned, the canards that are built from carbon, to some extent, all weigh more than their glass counterparts. The Berkut is heavier than the LE, and Chris Esselstyn's stretched COZY is heavier than a standard one, both after normalizing for engine weights and retracts. Go figure.

 

Maybe the guys who drew up the plans had a clue? The COZY plans aren't perfect, by any means - god knows that I've had more than my share of "discussions" with Nat regarding improvements that could be made, and a cursory search of the COZY mailing list archives would show that. But this isn't one of those places. Either for the COZY or the L.E.

[rsrguy3]

Marc, thank you for taking the time to respond and share your experience. I'm just trying to learn here, and the only way I can do that IS TO ASK QUESTIONS. Could you have been more condecending-I think not. I'm guessing if we were having a conversation face to face that there is no way you would be that rude to me. Unless, of course, you're one of those overly pridefull, under socialized, intellectual types, who thinks his education and career give him cause to be callously pious. I sincerely hope that this is not the case, and you are instead just having a bad day. I'm only looking for enlightenment. Thus the thread, to gain imperical info for my foray into composite building. In the future, if my curiosity irritates you please just use a copied link from the thread that applies, since I'm certain that your coarseness was a buy product of having discussed this way to often.

 

-Thanx again, Guy

[TMann]

Lots of opinions on Vacuum Bagging. The Cozy Girrrl(s) have a technique they use that they refer to as lo-vac. I use the regular method.

The only piece that I have not 'bagged' to date is the exterior of the fuselage.

 

I like the results. Sometimes you need to be a little creative but much can be done this way. I believe you'll find that the 'plans' method for the Berkut wings involved both carbon fiber and vacuum bagging so there is a lot of variety in technique.

 

While it is percieved that we are not using molds, we in fact are. Most people think of a mold only in terms of a 'female' mold but we use the 'male' mold technique so the phrase 'moldless construction' is a bit misleading.

 

Bottom line I can't/won't say that vacuum bagging is right or wrong. What I will say is that your project is an opportunity to learn as many skills as you want to take on. Maybe you want to learn how to vacuum bag or maybe you want to learn how to weld or many it's none of the above. Myself, I don't have time to learn how to weld.

 

Marc, thank you for taking the time to respond and share your experience. I'm just trying to learn here, and the only way I can do that IS TO ASK QUESTIONS. Could you have been more condecending-I think not.

Guy, welcome to the forum.

I will speak to this (because Marc and I have already been through this.)

While Marc may not be real diplomatic he is very knowledgeable and can be very helpful.

 

The forum is sometimes not the best venue because whatever we say here is public domain.

If you ever call Marc or email him directly, you'll find the experience to be quite a bit different.

[Marc Zeitlin]

Marc, thank you for taking the time to respond and share your experience. I'm just trying to learn here, and the only way I can do that IS TO ASK QUESTIONS.

One other way is to research the areas of interest before asking questions.

 

Could you have been more condecending-I think not.

Had I been intending to be condescending, I would have been. All of my comments were statements of fact.

I'm guessing if we were having a conversation face to face that there is no way you would be that rude to me.

I wasn't rude. I was presenting facts for the umpteenth time.

 

I'm only looking for enlightenment.

As are we all. I, however, have never felt that anyone owed it to me to hand it to me on a platter, and got upset when they gave me the information I was seeking.

 

In the future, if my curiosity irritates you please just use a copied link from the thread that applies...

Maybe the obverse should be the case, and if you can't find the information you're looking for in archives, web searches, books or old threads here, then you can ask a question while pointing to the information that hasn't answered your question.

 

Feel free to put me on your "ignore" list - I'm rapidly starting to not give a crap regarding helping people not to do stupid things. I truly am beginning (after 12 years) to have an understanding for why some EXTREMELY knowledgable folks just keep their mouths shut, rather than sharing their knowledge, to all of our detriments.

 

I give up.

[Spodman]

Could you have been more condecending-I think not. I'm guessing if we were having a conversation face to face that there is no way you would be that rude to me.

Some of my more fatuous early questions on this forum received what seemed to me to be fairly abrupt replies of this nature, but when I actually trolled through the archive it was hinted that I should I found my questions (and yours) had been agonised and arguefied & footstamped and soapboxed about (and viewable in the archives of this and other fora) with no resolution different to that proposed in the first Canard Pusher newsletter that dealt with it. Unlike Marc I'm not qualified or competent to change the structure of the aircraft so I'm not going to. Are you?

 

My uninformed opinion is I would fly in a home-bagged/carbon reinforced Cozy, as I don't think such reinforcements would weaken the structure too much, and any weight increases resulting from the weight reduction program would be picked up in the weight & balance check.

 

Your profile is a bit skinny on information, are you not a United Statesian, like I am not either? If so you may be surprised

by the cultural differences exhibited by those that are. They will tell you things (good & bad) about their experiences which a more reticent Aussie would never do. They will also call a spade a f#$%ing shovel when appropriate. Cheers.

I give up.

Please don't. (Thinks: Gee, I can edit my post)

[rsrguy3]

TMANN,

Good point, I have already taken a couple of welding courses, I may even take some Aero eng. classes at the local U, since this has always been a passion. As far as bagging is concerned, my experience comes from modeling, and, my pops A&P work, both areas have been quite rewarding, and informative. This is where my enthusiasm for the vac comes from. If their are'nt enough benefits realized from bagging I"ll just build per early 80's technology. -Guy

[rsrguy3]

Maybe the obverse should be the case, and if you can't find the information you're looking for in archives, web searches, books or old threads here, then you can ask a question while pointing to the information that hasn't answered your question.

 

Feel free to put me on your "ignore" list - I'm rapidly starting to not give a crap regarding helping people not to do stupid things. I truly am beginning (after 12 years) to have an understanding for why some EXTREMELY knowledgable folks just keep their mouths shut, rather than sharing their knowledge, to all of our detriments.

 

I give up.

 

Unfortunatley, actually fortunatley I don't spend that kind of time on the web that is why I started this thread- to get a comprehensive list of mods. It was never my intent to irritate. So like I said please copy over to this thread so all the info and debate is here in one spot. Or not.-Guy

[chasingmars]

Unfortunatley, actually fortunatley I don't spend that kind of time on the web that is why I started this thread- to get a comprehensive list of mods. It was never my intent to irritate. So like I said please copy over to this thread so all the info and debate is here in one spot. Or not.-Guy

This is part of what sometimes I think forms a seed of the irritation some of the *ahem* older (happy belated bday Marc! ) more experienced posters here (which I'm not one) feel sometimes I think. Mostly because it presumes the ten minutes you would need to spend using a search engine to find the answer to your question is more worthwhile than the ten minutes it takes for someone to answer your question. Of course, value there depends on perspective, and I've sometimes also been guilty of posting a repeatedly discussed question without first searching. I try not to though.

 

anyhow, I'm a vacuum bagger, starting chapter seven, my opinion's been posted, and to be honest, it's not worth it.

 

that said, I'll disagree with Marc on cosmetics. it's easier to get a nice looking part vacuum bagging than hand laid as I never seem to get even small bubbles that would be acceptable. I also use proper materials from composites suppliers and bag at high vacuum where the underlying foam warrents, and have had generally good results, at an expense that really just isn't worth it. But it's fun, and once a part is in the bag, it keeps me from my fatal flaw of poking at it just to try to make it a bit more right until it's ruined

 

I agree with Marc on the structural issue. These planes are plenty strong for their mission goals, and changing the mission goals gives you more issues than just weight reduction solves.

[chasingmars]

Could you have been more condecending-I think not.

Heh, you wouldn't be the first to mistake a very direct manner for condescention or arrogance...

 

While I've never met Marc, I've come to the opinion that it's simply a strong case of the (un)common hazard of being an engineer. We tend be misperceived like that sometime...

 

God knows why?

 

[rsrguy3]

I value your opinion. Like I said all I'm looking for is a list and a friendly exchange of pro's and con's, hopefully all in one thread.-Guy

[David Clifford]

Guy, No need to lash out at Marc for his response. After you have been around a while, you will see that that is his style of writing. It is not meant to be condesending, just to the point and factual based on experiance and real data. Now,,,had he or anyone else failed to respond to your questions,,,,,THAT would be a tragedy. Read and learn Grasshopper,,,,,read and learn.

[Drew Swenson]

<snip>Unfortunatley, actually fortunatley I don't spend that kind of time on the web that is why I started this thread- to get a comprehensive list of mods. It was never my intent to irritate. <snip>

 

I would say (in a very friendly tone mind you---- ) that you should NOT be deviating from the plans AT ALL if you don't have the time to search the web.

 

Just to follow the plans, you need to take the time to read ALL of the newsletters. To deviate from them, you need to research what the effects (and sometimes second and third order effects) of these deviations are.

 

Don't use bigger bolts because they look stronger----don't put on extra plies because you think that more is better----don't switch materials because you heard that the other material was stronger (and more brittle--and more susceptable to builder "slop", etc).

 

Deviations from the plans WILL TAKE MUCH LONGER TO COMPLETE.

 

Marc is pointing out that many people are improving things that don't need to be improved.

 

I am an engineer----but don't have the time to re-engineer the plane to suit my tastes. I have instead stuck with modifying noncritical parts of the plane.

[Jon Matcho]

Guy, please reread Marc's original reply and consider that he took valuable time out of his day to answer YOUR post. I understand how you might feel lectured to, but having been there myself (with Marc) and having gone through the process (almost graduated) of learning Composite Rutan Canard Building 101 with others, I would definitely recommend soaking in what Marc has to say in whatever manner you can manage best.

 

I have met Marc in person, may have pissed him off, and he has pissed me off in the past, but I consider Marc a friend (to myself and the entire community) and any disagreement we may have had is most often in my own head.

 

I wasn't rude. I was presenting facts for the umpteenth time.

Ah... the "spice of Marc". Some get stuck on statements like this.

 

Like I said all I'm looking for is a list and a friendly exchange of pro's and con's, hopefully all in one thread.

Again, please don't take a flood of factual information sprinkled with a little 'spice' to be UNfriendly. Appreciate the point of view, and formulate YOUR opinion. Also, your topic is very broad and the consensus 95+% of builders have is to use fiberglass. There are no clear answers to your original question #3.

 

In any event, welcome, and enjoy the forum and community!

[Neverquit]

Quit kissing up guys. He'll learn we're not all that we seem eventually.

 

Welcome to the hazing rsrguy3.

 

If their are'nt enough benefits realized from bagging I"ll just build per early 80's technology. -Guy

I believe you're still in early 80's technology. Ask your pop.

 

They will tell you things (good & bad) about their experiences which a more reticent Aussie would never do. They will also call a spade a f#$%ing shovel when appropriate. Cheers.

Hey Spod, not all of us. Your bias is most likely from the ratio of "United Statsians" to Aussies on the forum(s). I call foul even if there was T.M.I. about bottles and such on the Cozy mail list yesterday. A f$%^&* shovel is a shovel. A spade is on playing cards and a different shaped shovel. In the States we call a spade a spade when we see one (you "United Statsians" know what I mean). What the H#$% is a "spanner"? It spans nothing. Just kidding around. Cheers to you Spod.

[TMann]

Sigh. It looks like we're still in Kansas Toto.

 

The problem with these types of threads is that they never stick to the topic/question and so instead of responding with an answer, the response is instead a question asking the poster to justify the question.

And yes for the umpteenth time we have a comparison between techniques/materials that restate the same arguement:

If it's done right it would be stronger, lighter yada yada than the plans part/technique, BUT if its done wrong it would be weaker, heavier, smell really bad and snag your girlfriends nylons.

 

Compared to what? Compared to the plans part done equally wrong?

 

How bout this one:

When replacing unifiber spar caps with Carbon Fiber tape, if it's done right, it will be stronger, lighter, etc. BUT if you don't align the fibers correctly, you could end up with a weaker part.

 

Having worked with both, can you guess which one is more likely to suffer the alignment problem? (the glass). I'm not sure how you can screw up the alignment of 3 inch CF tape.

 

Most builders are not going to cross the CF boundry because of the cost. Yes, it is highly doubtful that you could ever suffer an in flight structural failure as a result of any of the glass parts without passing out first due to the G load. So to that end, using CF in place of glass is a hard sell. (Does anyone here think they could pull enough Gs to damage a canard?)

 

Maybe a little CF here and there for added stiffness/snarkyness but structurally not required.

 

"When built to plans"

I love that one. I would love to look over any canard built from anyone using this matra and do a checkoff of every item that is a deviation from "The Plans". Be it an electric actuator for the nose or landing brake or a slightly different approach to shape of the nose, they are still a deviation from the plans.

 

The larger rudders and internal belhorn did not come out of RAF. They were developed by builders and later adopted as a good mod and documented by RAF. The Cozy Mark III was a mod of a Long-EZ. The offset of the control tube on the elevators was invented by ........... a builder.

 

As far as the perception of respondants being percieved as being 'Marcastic' it all starts with (for example) the first word in this post.

 

Now I will say this, Marc is extremely good at what he does, you just have to realize that in a public forum, his delivery is not going to carry any diplomacy. To that end, one has to realize that this is a public forum. The Ideas discussed here may be hazardous to your health.

 

The Long-EZ plans were written to provide the builder with everything they needed to know to build a safe, fast, cheap aircraft in the EZ-est way possible. That was the starting point.

[chasingmars]

Compared to what? Compared to the plans part done equally wrong?

 

Nope, compared to glass done acceptably. A level of workmanship adequate for safe construction of glass, generally, would seem to be inadequate for carbon. While I haven't worked with carbon, so this is based on research and speaking with those who do, the bubble size limitations, fibre alignment limits, etc for glass would all have to be tightened for carbon due to it's brittle fracture, stress riser sensitivity and such.

 

I'm not sure how you can screw up the alignment of 3 inch CF tape.

 

It may well be easier to get good alignment with a carbon tape, but what about you uni/bid replacements? either, you mix materials, which requires reengineering to look at a carbon spar cap in a glass wing to avoid undesirable load transfer, or you sacrifice drapability to manage ease of fibre alignment, or you wrestle with fibre alignment.

 

Maybe a little CF here and there for added stiffness/snarkyness but structurally not required.

 

And this is really the heart of the contention I have with how this stuff is presented. Carbon is so expensive, there is a genuine risk that people just "throw a little in" on the mistaken impression it will add strength.

 

A laminate over a foam core is (essentially) constrained to uniform strain in each skin (an approximate that I ask the engineers to excuse). Carbon being so much stiffer reaches it's failure strain before the glass has taken up appreciable load, so the when the panel is deflected, the Carbon initially takes all the load with the glass doing little until the carbon fails, leaving the glass in a damaged panel to now take all the load without the carbon's help.

 

A little carbon here and there for added stiffness, if you don't engineer it properly, is one of the easiest ways to make your plane unsafe.

 

TMann, you're use of carbon, taking a major subassembly proven elsewhere and adopting it, ensuring the load paths are through structures that are either to one design or the other and meet at a interface that is common to the design is quite reasonable. throwing in some carbon for stiffness however, is not.

[TMann]

sigh.

 

Originally Posted by TMann

Compared to what? Compared to the plans part done equally wrong?

Nope, compared to glass done acceptably.

That's the point I was trying to make. If you are going to compare a finished part to another finished part, then compare the same quality of workmanship.

 

If the point someone is trying to make is that a material is less forgiving of poor workmanship then it should be stated as such.

 

sigh ......... maybe I'll cut my wings out this weekend. [/sigh]

[rsrguy3]

You guys rock! Any additions to mods listed by TMANN-Guy