argoldman

Hi all,

 

I need some help from the electronically gifted, a group that I do not include myself in. I built a DC power supply (to use for hotwire cutting).

 

I followed the instructions on the link provided below.

 

http://www.wikihow.com/Convert-a-Computer-ATX-Power-Supply-to-a-Lab-Power-Supply

 

In stead of having several DC poles sticking out of it, I created a switch that would switch between 6V and 12V. I further added a potentiometer (from a light dimmer) to control heat.

 

When I switch it on, I can see the voltage go up and down between 0v and either 6V or 12V respectively, depending on the switch position.

 

However, as soon as I hook it up to the hotwire saw, the voltage drops to 0V across the poles.

 

I also hooked up a 12v lightbulb between the poles. Nothing. Not even a glimmer. When I hook the multimeter up in series, I can see voltage displayed, but 0A.

 

I don't understand. How can it display 12v, but 0A?

 

Any thoughts?

 

ZY

 

The real question is does the wire heat up.

PAf,

 

The above figure, I believe is for the plane and engine.

 

A good way to determine the value of a project is to look at the cost of the materials that have gone into it (cost available from ACS by chapter) and go up or down from there.

 

If you are interested in buying a project, or aircraft, for that matter, find someone really familiar with the CO, LONG, Veri--EZs so that a proper prebuy inspection can be done.

It really depends on what your mission is.

 

If you fly alone, either one would suffice.

 

If you fly with another, how does he/she like the view of the back of your head. Perhaps not being able to share the visual aspect of communication is a plus, in some relationships.

 

The Q bird is a side by side plane. It has, with both seats occupied, little room for baggage. If you consider this bird, also consider a dragonfly. Similar, a little more cheek room (face not butt) in that the canopy shape is more square. It is slower but is lands slower.

 

The V-E, being tandem may get tedious for a frequent back seat flyer, I personally get pleasure seeing the reactions of my passengers as I fly. I don't know if baggage pods can be put on the V-E.

 

Depends on what you like (and how much elbow room you need)

I may soon be purchasing a Q2 that has fuel damage into the foam core in the main wing from a fuel leak. I wonder how difficult it will be to remove and replace that wing, or whether I may be in over my head with such a project? My plan would be to purchase an already built wing and install it myself. Any thoughts or warnings?

 

Thanks!

No repair to a glass aircraft is specifically terribly difficult, assuming you know how it was originally built and good glass repair techniques. Glass, fiber orientation and margin coverage are all vital.

 

One difference between the Q birds and the dragonfly wings is that the Q wings are permanently glassed into the airframe. The dragonfly wings are attached much the way of our canards in cozy land, ie tabs and bolts.

 

What would be involved is cutting the old wing off and grafting a new one on in its place. Recommended tools would be a Fein Multimaster and a Rotozip (dremmel on steroids.) Get a set of plans so that you know the fiber layup schedule and fiber type and direction.

The whole Idea is to drop the nose so you can create some airspeed to get the canard flying again. Dropping the main wing first would cause the plane to try flying backwards. Never a good situation.

 

Even Bi-planes have a different angle of attack (Top wing vs. Bottom wing) in an effort to reduce the dramatic effect of the stall.

Almost right, My Mann,

 

The idea is to keep the wing and it's ailerons flying and acting properly in all conditions and never achieve the angle of attack at which it would stall. As was mentioned before it is the angle of attack, not the airspeed that controls stall. The canard is scheduled to stall at a lesser angle of attack than does it's attached wing. In the typical canard "stall" there is really not much of an airspeed increase, if any, however the canard, when reaching its stall angle of attack will stall, the plane, rotating around the C/L of the still flying wing will decrease the angle of the canard, to the air stream (relative wind) bringing it back to the realm of the flying.

Swing wing cozy, anybody????

Does anyone have a pic of the heat duct under construction to give me an idea of size and exact location, as i said I am merely thinking of the changes and have no technical data because of my lack of plans.

 

I also have thought of just widening the seat, but I like the idea of a "fighter" style cockpit. Since the Cozy is designed in part from the Long Ez which is a tandem seat aircraft I thought it would be a fairly simple modification. Possibly building up the sides around the center mounted seat to house the flight controls and have a place to run any plumbing to the rear of the aircraft. I also like the idea of a stick in the right and the throttle quadrant in my left hand.

Right hand sticks are good as long as you are left handed or never plan to write down a clearance or anything else for that matter. When this becomes a necessity, you, unless you are ambidextrous will have to grab the stick cross chest (dicy at best), keep the plane under control, and copy the clearance, draw your lines on the chart or readjust yourself.

 

If you consider a store built aircraft, stick or yoke, you normally fly the plane with your left hand for this reason.

 

Southpaws need not apply

 

Rich

I have family in the Chicagoland area and take trips there often. Who knows if work will allow it I might look up a few builders and pick there brains for an afternoon.

 

Talk about slim pickins-------

 

I look forward to hearing from you

My project is at Kenosha Wi (ENW) just north of the IL/WI border

Welcome to the fold, fellow Illinoisian. I am in the Chicago area (Up north to you-- sans Miegs field)

 

If you are ever in the area, give me an e-.

 

I look forward to meeting you at OSH.

It seems like we are making a wing out of a canardhill here.

 

While there is no problem purchasing the cores,(which I highly recommend), hot wiring is quite simple, and quite rewarding. The thimble (bobbin) thechnique seems great, however with that little chunk of metal there, it will be difficult to accurately tell the wire position on the template. Positional relationships are important, and critical on corners, such as spar cutouts. Additionally, the inner flange of the bobbin must ride between the template and the foam tending to either crush the foam there, inadvertently ride high or move the template away from the foam. Two objects cannot occupy the same space at the same time (yet).

 

It seems as if, with the exception of no-one being available to handle the other side of the saw (On my dragonfly, I used my 11 yr old son), the problem you(s) are having is with the selection of the template material, and the finish on the edges.

 

Whether it be masonite, metal or even formica, the edges must be smooth and polished with no nicks. If the edges are not smooth or benicked you will have problems.

 

If you are going into production, by all means use a thick wire as wear does have it's say, however with the relatively small amount of hot sawing you will do on your wings and canard, it is really unnecessary.

 

Get to know the process. It is not as daunting as it seems. Thousands upon thousands of wings, etc have been made successfully by it's technique.

 

For my dragonfly, I used thick safety wire. I made little handles (1"dowells center drilled), which I placed on the wire and orentated them just outboard of the templates during the cutting. I suspended the saw from a counterweighted pulley affair from the ceiling to make it almost weithtless and guided the cut using these little handles.

 

It's fun and when you see the shaped chunk of foam you produced, with so little effort, it gives you a real shot in the wing.

I'm very frustrated with my lack of progress. I've had my plans a couple of months now and do not see light at the end of the pre build tunnel yet.

I pay as I go:D

 

90% tools purchased

I thought I had plenty of basic tools until I got my hands on my plans and started pricing everything that will be needed.

I went through a lot of money just buying tools and reached the realization that unless I slow down my preparation purchases I'll have lot of tools a nice shop an no material or money. I don't think I could sit still for having everything ready to start and no money to begin.

 

I was not planning on opening the boxes that some of my larger purchases came in but just had to do something so I unpacked and assembled my new radial arm drill press. Or at least started to... it seems to be missing a bag of bolts and a set screw. I plan to get some case hardened replacement bolts as the ones missing attach the press to it's base.

 

With this wakeup call I unpacked the Harbor Freight 4 speed band saw the Cozy girls recommended and assembled it too.

 

I elected to go with cheap drill bits and a drill doctor rather than spend a lot on bits. I snagged a Fien Multimaster XL kit which comes with a number of blades; I hope they last well as the blades are expensive.

I still have a few hundred dollars worth of tools to buy but all the major purchases have been made.

 

80% basement shop & layup room

I have to clean the shop soon if I'm ever going to get the drop ceiling in with the 5 4 bulb 4 foot long florescent fixtures I bought.

 

Garage

Still have my boat in one of the garage bays, if my brother does not come get the boat soon I'm going to sell it (he gets if free if...).

 

0% table and cabinets (may convert an old fridge for the expoxy cabinet)

 

Feels like I've got a rich mans taste and a poor mans wallet.

 

Distraction:

In the middle of all this I have to buy a welder (MIG) to finish another project.

Some felllow with no insurance hit my 66 Impala so I'm doing a chop and reskin on the drivers side rear quarter. I know a lot of people use flux wire welders but they honestly are crap compared to a mig. Flux in the weld, a lot of dirty splatter and lower quality to boot. I know I could go cheaper but my long term plans call for a true gas shield mig.

Replacement motor for my washing machine arrived damaged so had to buy another one to expidite repair. Sending the damaged one in for credit

 

So Ken,

 

What is really holding you up??????

First I heard this one. Is this based on experience, forum feedback, MGS?

Is this true about 285, 335 or both?

I just switched to 335 and am using the slow hardener and would appreciate some info on the subject.

 

It is with the 285, don't know about the 335.

 

I don't know where I read it, possibly the data sheets from MSG, but I remember not to do it, even though I hadn't planned on it.

 

Sorry I can't be more specific. A call to the MGS distributor will probably clear up that questioin

But using a pump will not allow you to use both slow and fast hardener - right? I like to use about 3/4 slow and 1/4 fast - gives a good compromise of cure time and working time for my workshop. As the weather gets warmer, I can use less fast as desired. How could you do this with a pump?

Yes,Phil there is an epoxy pumpaclaus.

 

you can adjust the ratios using a pump by the following method.

 

Keep a small amount of your desired "hardener" mixture in the reservoir of the pump. As you get more experience with the pump, you will know the amount to keep there. When you want to change the ratios just add more "hardener" in the ratio that you want using slightly more of one or the other to compensate for the small amount of improper ratio which still remains in the pump. Stir the new mixture with a chopstick or similar. You can fully load the clear resin (part A).

 

In actuality, you will settle on a specific ratio that you find works well for you for most parts and only in specific incidences will you want to change it.

 

Do not ever use only slow hardener. I understand this yields a more brittle cured epoxy

So it doesn't sound like there are any specific roadblocks that should prevent me from building the wings first, except proficiency. On the previous project I worked on, the Dragonfly, the plans have you start with the fuselage sides and bottom, but you can't assemble them until you build the wing because it is needed to perform a critical alignment for the fuselage assembly. It seems like the Cozy4 is similar in that the wings can be completed without needing to have anything else done first.

As far as proficiency goes, I did complete the Dragonfly bulkheads, sides, bottom, turtledecks, and a wing. Given the apparent similarity of construction, I'm thinking I should be ok jumping into the wing build on the Cozy4. My only concern at this point is if I go with MGS epoxy, since it might behave differently (viscosity, wet-out, pot life, etc.) than the Aeropoxy that I have gotten so used to.

 

Joe

 

Joe,

 

Your experience with the dragonfly will serve you well. In that case start anywhere you want to.

 

One thing I would suggest is to do some of the bulkheads and get used to the handling properties of the MGS.

 

You will love the way it wets out. HOWEVER, because you have the ability to control the setting speed by adjusting the ratios of the hardeners, best to learn the ratios that you need to do various types of layups.

 

I use only a fifty-fifty mix (of fast to slow hardener), and it has served me well (after a short learning curve). I have to admit that I chickened out and had Dennis Oelmann build my wings. I want to be young enough to fly the beast when I finish it. However the 50/50 mix would set way to quickly for that procedure.

 

From my memory, the aeropoxy has a relatively long pot life. at 50/50 the pot life seems to be, in 70 degree temps, about 20 min (you must work fast) In higher temps, even less. Much of this has to do with the bulk of epoxy in the pot, as if you do layups on a table (with plastic, such as tapes, etc) once wet out, they can sit and be supple for an hour or so (again dependent on ambient temp.)

 

There is one main difference between the Cozy wing and the Dragonfly wing and that is the spar caps. The d-fly caps used carbon tows, relatively easily wet out while the cozy uses what appear to be fiberglass ropes. Having used them in other applications on the plane, they are harder to wet out than were the carbon caps so factor that into your timing. I found that the ease of wet-out of the MGS to much more than compromise for the downside.

Hi all!

In terms of the way the Cozy MKIV is supposed to be built, is there any reason why I couldn't build wings first, then do the fuselage and everything else?

I'm considering some modifications to the fuselage and it will take some time to make the decisions, figure it all out, design it in CAD, etc. But I don't want that to slow down the overall project, so I want to work on the wings in the meantime. I already have some glassing experience from my previous project, so proficiency shouldn't be an issue. Just want to make sure there isn't some technical reason why I shouldn't be building out of sequence.

 

Joe

Joe,

 

The skills needed to properly build a composite aircraft are not difficult in themselves. However, like any skill, they are not a natural part of our existence and must be learned. there are many things that you will learn by doing the glassing, many mistakes, many OH SHI*S (for those faint of ear). So much better to do them on the bulkheads, seat back and easily done lay ups which have a relatively low cost of redoing, or are not as critical with respect to excellent lay ups as are the wings, nor do you have any huge time investment in those individual pieces as you would have in the wing.

In short, start with the simple bulkheads and work yourself up to the more complex structure. Ultimately, doing it this way, you will save yourself a great amount of time and $$. The plans are generally written to expand your skills as you go forward.

 

Now, if you have a lot of glass aircraft building experience, start anywhere you want. Read the plans carefully to determine if a piece that you intend to build must be custom shaped to another piece before glassing.

 

Good luck with your project.

Rich (argoldman);

 

It’s good to see a familiar name on this forum, to which I am relatively new. I followed your progress on the Dragonfly for several years through that discussion group. It was a shame to hear of the loss of that plane. But it’s nice to see you’re back at it with the new project.

 

I'm trying to do my homework and determine which epoxy I’ll be using on my future Cozy. It seems that most Cozy builders are using MGS for one reason or another. If I am not mistaken, you are also using this product.

 

I'm leaning toward Aeropoxy since it is available locally and I'm already somewhat familiar with it, having gotten part way through my Dragonfly project.

 

Based on your experience with Aeropoxy on your Dragonfly, and now MGS on the Cozy, could you comment on how the two products compare, and why you didn’t just stay with Aeropoxy?

 

Joe

 

Greetings Joe,

 

It's good to be able to physically be able to work on a new project. The remains of the dragonfly are in the hanger next to the new thing sprouting wings.

 

Now to epoxy. In my dragonfly I used a variety of epoxies starting with safe-t-poxy, and finishing up with Aeropoxy. I found aeropoxy to be a good product with the exception of its viscosity, which made the wetting out of the cloth more difficult (although I didn't see it as such since I had not used other easier to use products.) Because of it's viscosity, it was easy to incorporate tiny air bubbles into the mix, which, by the way, would disappear as it was being used. The color was great, and the smell acceptable (somewhat sweet, from what I remember.)

 

I started using MGS 285 system because it "seemed like the thing to do" with the cozy crowd. The material is virtually orderless (unless you directly smell the "hardener")

 

The material has very low viscosity, mixes well and is a dream to use. It wets out fabric very easily. I use a 50/50 mix of hard to slow "hardener" but you can adjust the cure time by adjusting the ratios.

 

I really like the stuff.

 

I went to the Arocanard factory to make my parts in their molds and we used EZ-poxy-- smelly, viscous, dark in color, and not nearly as easy to use as MGS. I couldn't wait to get back to my hanger and get back to MSG.

 

When MSG became unavailable, I switched to Pro-set. This material was probably the best wetter-outer of the group but the setting time was longest, about 24 hours or slightly more.

 

MSG as mixed above was ready to sand at 12 hrs.

 

I finished my one gallon of Pro-set, was then able to get MSG and that's what I will finish my plane with.

 

Being located in Canada, you will not have the kind of problems with shipping, etc., that we have.

 

I like the stuff. I suggest you use a pump for dispensing.

That's the plan, if necessary.

 

 

 

Yup. I use a respirator whenever I do any epoxy work. To keep the rest of my family from breathing the stuff, I will set up a high CFM bathroom fan exhausted to the outside, with a furnace filter in front of it. That should be enough to put the basement workshop at negative pressure w.r.t. the rest of the house so the direction of airflow is from the house into the basement shop and then outside. The filter will catch sanding dust.

 

BTW argoldman, did you get my private message regarding your choice of epoxy?

 

Joe

I started with the same type of fan in my basement window, I found that it was inadequate (or at least my wife said so due to the smell). I replaced it with a window exhaust fan (can't remember the size although it was the biggest that would fit in the window. That was excellent.

 

There was one problem, however, that didn't show it's face (or other part of it's anatomy) until the winter.

 

When I lit the pilot for my heating system and cycled the furnace, flames shot out of the back of the unit. I quickly shut the heat off and the flames disappeared. Trying it again. I got the same result and surmised that something was wrong. we called a chimney person in, and he came to the conclusion that the chimney had a reverse draft and would have to be dismantled and rebuilt. We were not amused.

 

It all of the sudden hit me that the window fan in the workshop was drawing air, not only from the house, but was drawing air down the chimney.

 

Shutting it off cured the chimney back draft problem. Thereafter, I opened a basement window to replace the air being exhausted.

 

Could you resend the email about the epoxy, things have been rather hectic here lately-- I fired my assistant/office manager and have been running things myself for the last couple of weeks and much has slipped away.

Richard;

I'm planning the Cozy4 project (without actual plans yet) and want to determine if a completed wing will fit through a basement window. Next time you're doing something with your wings, would you mind measuring the widest point (i.e. longest chord length)?

Joe

 

Richard,

 

It is possible that your wing will fit out of your basement. I built my dragonfly wings in my basement, as a matter of fact, I built all of the fuselage parts in the basement and assembled most of them in the garage.

 

HOWEVER.............

 

Getting the parts out may be a problem based on how deep in the ground your windows are, their width. and available height plus the angle that the part has to be to get it out of the window.

 

What I did was to build light mock-ups of the parts with which I had concern and successfully tried to get them out of the windows. Once success was suspected, I merrily went along my way to build the wings/ canard. When it came time to get them out of the basement, I hadn't considered the actual thickness of the wings and when trying to get them out of the windows, through the window wells, the angle necessary to clear caused the part of the wing that was in the basement to jam against the floor while the outside part jambed against the window well and the top of the window frame.

 

Frustrated, I was just about to rent a jack hammer and make clearance when my 11 yr old son looked at the situation and said, "just dig some dirt away from the back of the window well, make two vertical cuts, bend the tab thus created down, and thus gain the vertical space necessary." After thinking, " go away, kid, you bother me." I reconsidered and indeed extricated the wings in that fashion.

 

Make sure that you have adequate ventilation pumping air outside. That epoxy can be nasty stuff (mgs not withstanding)

Looks great.

 

The first thing you have to do is get rid of that manual nose gear mechanism and replace it with an electric.

 

From those pix, the workmanship seems to be good.

 

The fuselage seems to be in the proper place in your house, in the living room!

 

My Aerocanard SX kit is on its wheels, two years into construction with about 8 months left to go. If you need any clarification, give me a shout. Perhaps if somebody gives me some dual on posting pix on the web, I can get some posted.

How can winglets produce "thrust", i.e. a forward force. In ground school we learned that an airfoil produces a force normal to the chord which can be split into a vertical lift component acting up and an induced drag component acting back. (This should be true for any airfoil.) There's no angle of attack that can produce a forward component of that force. So if the winglet is basically an airfoil on its end, why should it be able to do this?

 

Joe

Because there are two winglets, rigidly connected to each other and producing lift opposite "lift" toward each other, one explanation might be the same force vector that exists when you squeeze a watermelon seed.

 

Slurp

I am curious if anyone has bought the aerocanard dvd set. If so how were they? Cheers fellas, JOSH

Greetings Capt. Hook,

 

The aerocanard disks are a record of Jeff building, what seems like, 3 different aerocanards from kits. Because the tapes are not shot in a linear fashion, following any single part (with few exceptions) is difficult--no, chaotic-almost schizophrenic, as the part may start its manufacture in disk 3 and finish in disk 7.

 

The quality and audio is more than acceptable, although not professional. As things are being discussed, air compressors cycle, phones ring, rain pours on the hanger roof, and Jeff's cat even makes an appearance.

 

These disks are a must for anybody considering the Kit, or any of the major kit components. As a matter of fact, many times the material on the disk is much clearer than the instructions, although you need both.

 

For those building from plans, the disks will be beneficial, although no as much so as for the kit or with some prefab parts.

 

Viewing the disk set, it is very easy to get lulled into seeing how easy it is to build these beasts, and how short a time it will take to accomplish a specific task. When Jeff does it, everything fits perfectly the first time. What takes him 10 minutes to do on disk, will take you, and probably him, off disk, 3 days.

 

Additionally, the disks are not a complete record, Some non-major tasks are omitted

 

I give the disks 3 1/2 canards up (out of 5).

......mike,

 

I agree with trying to get the materials at the minimum cost. Years ago, when Burlington Mills tried to "horn" in on Hexel's grip on the rutan-type fiberglass market, large hues and cries went up by---Mr Rutan including the threat to ACS, I believe that if they carried the product, that He would withdraw his support for their supplying EZ material. I also believe the same letter was sent to Wicks. (this was about 20 years ago). I got the Burlington stuff for my dragonfly

 

As you might know, the plans developers or rights holders got, and possibly still get a percentage of the sales from items ordered for a specific aircraft. (that's why they ask you what kind of aircraft you are building). This represents a good chunk of change worth protecting.

 

In those days, the Burlington weave was sold by a company called Alpha plastics, I believe Ira Hale was the owner. He didn't pay off and passed the savings to his customers. War ensued but finally calmed down. Alpha plastics was bought by another company, and that company was bought by, I believe ACS. (interesting how these things go around)

 

That being said, make sure that you know the supplier of the material that you are buying from. When a deal looks too good to be true, it usually is.

 

Fiberglass is treated with a chemical coating which is the intermediary between the epoxy and the glass. (epoxy will not stick to the raw glass). This is a fairly fragile coat and can be destroyed by moisture. I'm not sure what the shelf life of the coating, if any, is. If you get your glass from a supplier that moves great quantities of the stuff, you will probably be OK, but if you get yours from a place that found a roll in the back and wants to unload it at a "sacrificial price" Beware.

 

Epoxy doesn't seem to have a shelf-life, however the way it is stored might make a difference. Additionally, the suppliers usually get the stuff in large quantities and fill small containers for sale. Can you be certain that you are getting the exact material that you are ordering, or is it somehow "expanded" to maximize profit. The homebuilt world is full of many sharks, both in plans and material suppliers.

 

Just be aware of from whom you are buying. Balance the potential savings (in % of total project cost) against the potential downside.

 

Enjoy your build and education.

I use an automotive oil filter with a bypass valve. I hand tighten it (as hard as I can). I always need an oil filter wrench to get it off---and needs a pretty good tug too.

 

I would definately safety it if I could---but there are no "ears" for it. The filter is real cheap too.

 

Not advocating this as the way to go...but it is A way...and carries some risk. What is your risk tolerance?

 

Has anybody thought about slipping a large hose clamp around the lower body of the filter to act as a wire-ty fixation point?

 

The clamp can be reused, practically forever, on successive filters.

Here is a cheap tool update. I think I would have been better off to just buy a brand new fein tool with the accessory kit. I just ordered cutting blades and a sanding tool for my new fein. They cost as much as the tool. I gotta figure out a way to make my own blades they are way to exspensive. I do know that this set up trims like a demon. I used the old saw blade that came with the saw and it trimmed so nicely that I know a brand new blade is going to do even better. STeve

Greetings Big,

 

If you have the saw that came with your unit and have ordered other blades, your blad stock will probably outlast the project. The plain steel ones seem to last forever themselves.

 

The little triangular sanding pads are a different story. They are plastic velcro type material.

 

One of the advantages of the unit is that it is a powerful sander, which you will see, however along with that comes creation of heat which, in the corners, if used heavily, melts the plastic and you then get less adhesion of the sandpaper and have to replace the pads ( I think I get 2 for about $13)

 

If they have a metal pad with adhesive paper, that might be a better deal.

 

Even though the cost is greater than I would like, The tool is so great that I am willing to put up with it.