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Re: Fiberglassing Techniques
jtenhave@mets.mq.edu.au <jtenhave@...>
Leon,
thanks for your comments, your points raise some interesting issues which extend the discussion beyond the scope of the original query - which is a good thing! In the interests of bandwidth, let me snip that which is not needed to continue the discussion. I have not found this to be a problem unless the core was way too wavy to start with. If you sand only until you see a blue (or orange) pattern appear that looks like a dried up lake bed you still have several thousandths of micro left to keep your sanding block from digging into the foam. No argument here apart from why bother with the extra work? If the core was correct, none of this would be necessary. Its so much easier to sand that it takes a really light touch not to damage the foam. I find that it takes me less time to sand a good contour with the "skin" even though it takes more "work". So, I might add, would using a lighter grade of paper on ones sanding board. We are not talking about a great deal of finesse here, just care. Aren't we supposed to "plan ahead"? About the only area where I have found a problem with loosing the contour is on the leading edge of the wing where lay-ups over lap. Other than this after several layers of (carefully laid) glass have cured a long block will still evenly mark the surface just as it did before the glassing. If the lay-ups are done carefully many times all the prep that is needed is a sanding with 220 and a coat of primer/sealer. I am interested to learn how it was possible to have planned ahead sufficiently to recess a hard shell for each spar cap laminate, to have permitted the uni skin to have joggled up and down the .009" steps required for each ply, ( 9 plys from memory on the Q1 canard) to have accurately predicted and allowed for the tapes which attach the flying surfaces to the fuselage, and to have allowed for the wing tip layups, the elevator and aileron slot layups, the wheel pant attachment layups and still be able to evenly mark the surface with a long block. (I am assuming that the block is being used spanwise?) Extraordinary stuff! >> Very true - But I do see a 2 very real over all benefits. 1); I think you get a STRONGER wing because as we all know the limiting factor is the compression strength of the materials we are working with and I find the glass fibers to lay much straighter when layed up on a flat and firm surface rather than over some squishy micro which always seems to move around when working the lay-up. It is unclear that the limiting factor is the compressive strength of the materials we use. in the case of our composite It is less than the tensile, but so is the peel strength and the bearing strength, so what? That is why different layup schedules are used. The limit is the stress that the part sees, hence the flight envelope and the weight limit. It is quite unclear why one would get a stronger wing because we all know the limiting factor is the compression strength....... Perhaps I am missing something here? I think you will have universal support for the assertion that having the fibers lying straight is desirable, but it could be that there was too much, too soft micro beneath the layup which was too wet which permitted the problems described above. The optimum amount of micro is that which just fills the cells of the foam. Remember that honeycomb cores have gaps of several millimetres between the edges of the cells. All you have to do is to provide a bond sufficient to transfer the shear loads carried by the core - as you rightly pointed out above....it is not a lot. And 2); I find it requires less over all work to get to the finished product. You are right, Leon but the quality of the product may differ. Other than items produced in a female mold it is hard to think of anything which would achieve the finish specified in the plans with a 220 grit sand and a coat of primer sealer. Regards John |
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Re: Fiberglassing Techniques
jtenhave@mets.mq.edu.au <jtenhave@...>
Pat,
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Single away, a valid assertion should be able to withstand sceptical questioning! let me play the devils advocate here, If no micro sticks when sprinkled on a resin rich surface ( whether or not it contains glass) why bother doing it at all? I am not advocating this as a practice, merely explaining why it was discouraged. I have never done it, why? because I thought it was a dumb idea, and at the time I built my Long Eze I had not heard of the method of wet micro on top of a tacky layup. Quite apart from the fact that at the end of a wing layup, I had run out of puff.... -and I had peel plied the surface....... With respect to optimal layups, I would have agreed with you to a large extent prior to seeing the experts at work, now I know that it is possible to make parts by hand that are much more efficient...resin wise and the best way of all is under vacuum. Incidently, optimal layups do not look like dry layups, they are uniform in colour and the bundles are discrete, hence the difficulty in sanding them to a uniformly scratched finish. A very good video on the subject is Mike Arnold's tape "How Its Made" describing the construction of the AR-5. If you are glutton for punishment, his "Making Fiberglass Molds" will cast even greater light on the subject. Regards John -----Original Message-----
From: Pat Panzera [SMTP:panzera@...] Sent: Friday, December 08, 2000 12:28 PM To: Q-LIST@... Subject: Re: [Q-LIST] Fiberglassing Techniques "jtenhave@..." wrote: John, not to single out your message, but rather this is to address this entire thread.... Is there any real proof that raw micro balloons spread over liquid epoxy could wick material away from where it belongs, or is this another hanger legend? If I spilled a bunch of epoxy on my hanger floor, the last thing I would use to try and absorb it would be micro... even if it were free. If it were free, I'd reach for flox first. Heck, when I WANT to mix micro with epoxy it's a serious pain in the rear! I would almost be willing to bet (almost) that if you mixed some epoxy and placed a dime size drop on wax paper, then sprinkled micro over the drop, the surface tension of the liquid would support the weight of the micro, and only the balloons which are actually in contact with the liquid would stick after cure. Additionally, I don't think the optimal ratio of resin to glass can be achieved by the process outlined in the plans. I believe that the hand process produces a epoxy rich lay-up, and if a builder ever saw a lay-up with the exact perfect ratio, he'd swear it was dry. Therefore I can't see how dusting micro over a completed lay-up could compromise the structure. In reality, I can see how it can help to maintain the structure, by reducing the amount of potentially destructive sanding called for in the step immediately before filling the weave. BUT!!! If prototype was built with a (presumably) rich mixture, and we are building knock-off's of the prototype and trusting our lives to it's flight test information, then in order to be secure in this information, we need to do it the same way the prototype was done.... or do our own testing. Pat I've dusted plenty of parts with a very conservative amount of micro, and it always seemed that after cure, almost all the micro came back off, except that which was directly in contact with the epoxy. To unsubscribe from this group, send an email to: Q-LIST-unsubscribe@... Quickie Builders Association WEB site http://web2.airmail.net/qba321tm/q-page1.html |
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Re: Fuel System Plumbing
kdvd@...
Mike,
Thanks for the response, I am glad to hear that in the 900+ hours everything has worked well for you. it feels like I have about 900 (building hours) into my bird and I hope to join the flying club someday. Thank you for the feedback, and maybe I'm cocerned about the wrong things. I will plumb the entire plane with 3/8 and stick to the plan. Glad to know the marine pump bulb works OK. Now I can order parts from Spruce. Thanks Kurt --- In Q-LIST@..., "Mike Dwyer" <mdwyer@t...> wrote: to-Kurt Van Dyke wanted to know what everyone is running for : gascolator;engine? (I planned 3/8 allthe way - hard plumbed to the pressure in theoverkill?)I built with the 1/4" and it does ok if you keep a positive tank. 3/8 is the best idea. Gascolator is a bad idea. Read backa bunch of posts.down fromB) Where did everyone mount their fuel pump?Mine is on a plywood pad that is mounted on the header tank.C) where theMine is on the behind right side of the center piece that comes the instrument panel.in-D)Is there anyone else out there that does not have a lot of for 5line check valve?I bought a new cheap bulb from a marine supply and has been working years. The one supplied from Q vibrated the check valve apart.This bulb is part of my preflight check.because,E) Who's running in-line fuel filters before theMe, one of those JC whitney glass micron things. tank vent.inevitably, I always seem have leaks when plumbing anything andAfter all done I blew up a baloon and ruber banded it to the fuel The baloon stayed filled until the next day (put a bit of grease onthe fuel filler cap). Flat baloon, you got a leak. |
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Re: Fuel System Plumbing
Sam Hoskins <shoskins@...>
By the way, I do use a gascolator.
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Sam Sam Hoskins wrote: Kurt; |
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Re: Fuel System Plumbing
Sam Hoskins <shoskins@...>
Kurt;
Good topic and you are asking the right questions. Scroll down for my humble opinions. kdvd@... wrote: Hello everyone,3/8" is excellent. Place the hose connections where you can replace them every couple of years. B) Where did everyone mount their fuel pump?On the bottom of the header, but that may not be the best. Lower is better. Probably not good to mount it on the canard, cause it it ever leaks...... goosh C) where theI put mine behind the panel. It doesn't have to be particularly easy to get at - just accessible. D)Is there anyone else out there that does not have a lot ofGood point. Internal bulb check valve is questionable. Another drawback of the leaky valve, it bypasses the pump so you don't get good transfer to the header. Maybe a better method would be a good quality in-line check valve, with no check valve in the squeeze bulb. E) Who's running in-line fuel filters before theI am. I use the clear type which can be had from Aircraft Spruce or at Auto Zone (don't use the fittings that come with it, get better quality fittings from Wicks or Spruce). I like it because when I do my run-up I can look at the filter and visually confirm that the transfer pump is operating. Use lots of epoxy inside the tank. Do NOT use sloshing compound. I lookedSpend lots of time on your fuel system, as it sounds like you are. Fuel systems are one of the highest causes of accidents in homebuilts. In the engine compartment, use aircraft fittings and hoses. Look at the fuel system connections in the engine compartment of a C-150. Consider the engine vibration. Interior. Don't use the vinyl tubing that comes with the kit, it hardens and shrinks. I use tygothane tubing that you can buy from McMaster-Carr, on line. It's extremely tough, stays flexible, and like me, it ages well. I'll send you a photo of my installation off line. Hope this helps a little. Sam Flying Q-200
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Re: Fuel System Plumbing
Mike Dwyer <mdwyer@...>
Kurt Van Dyke wanted to know what everyone is running for :I built with the 1/4" and it does ok if you keep a positive pressure in the tank. 3/8 is the best idea. Gascolator is a bad idea. Read back a bunch of posts. B) Where did everyone mount their fuel pump?Mine is on a plywood pad that is mounted on the header tank. C) where theMine is on the behind right side of the center piece that comes down from the instrument panel. D)Is there anyone else out there that does not have a lot ofI bought a new cheap bulb from a marine supply and has been working for 5 years. The one supplied from Q vibrated the check valve apart. This bulb is part of my preflight check. E) Who's running in-line fuel filters before theMe, one of those JC whitney glass micron things. I have dreaded (procrastinated) the fuel system construction because,After all done I blew up a baloon and ruber banded it to the fuel tank vent. The baloon stayed filled until the next day (put a bit of grease on the fuel filler cap). Flat baloon, you got a leak. Hope that helps, Mike Q-200 15 years, 900+ hours |
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Re: Fiberglassing Techniques
Pat Panzera <panzera@...>
"jtenhave@..." wrote:
John, not to single out your message, but rather this is to address this entire thread.... Is there any real proof that raw micro balloons spread over liquid epoxy could wick material away from where it belongs, or is this another hanger legend? If I spilled a bunch of epoxy on my hanger floor, the last thing I would use to try and absorb it would be micro... even if it were free. If it were free, I'd reach for flox first. Heck, when I WANT to mix micro with epoxy it's a serious pain in the rear! I would almost be willing to bet (almost) that if you mixed some epoxy and placed a dime size drop on wax paper, then sprinkled micro over the drop, the surface tension of the liquid would support the weight of the micro, and only the balloons which are actually in contact with the liquid would stick after cure. Additionally, I don't think the optimal ratio of resin to glass can be achieved by the process outlined in the plans. I believe that the hand process produces a epoxy rich lay-up, and if a builder ever saw a lay-up with the exact perfect ratio, he'd swear it was dry. Therefore I can't see how dusting micro over a completed lay-up could compromise the structure. In reality, I can see how it can help to maintain the structure, by reducing the amount of potentially destructive sanding called for in the step immediately before filling the weave. BUT!!! If prototype was built with a (presumably) rich mixture, and we are building knock-off's of the prototype and trusting our lives to it's flight test information, then in order to be secure in this information, we need to do it the same way the prototype was done.... or do our own testing. Pat I've dusted plenty of parts with a very conservative amount of micro, and it always seemed that after cure, almost all the micro came back off, except that which was directly in contact with the epoxy. |
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Re: Fiberglassing Techniques
jtenhave@mets.mq.edu.au <jtenhave@...>
Gene,
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This process straight onto the glass was discouraged because the assumption was that the original layup was optimal i.e. the minimum amount of resin was used to just wet out the glass cloth. By definition therefore, anything that drew resin from an optimised layup would result in a lean top laminate. The solution was to wait until the layup had gelled and then spread the minimum amount of micro over that surface, a reasonably wet mix makes the spreading of a thin layer much easier. At this stage you can sprinkle micro to your hearts content which will result in the leaning out of the wet micro mix and a much easier layup. I would like to be able to take the claps for this, but I learnt this technique whilst working with Dave Ronneburg building the prototype Berkut. One caveat is that this process denies you the opportunity to inspect the skin to whatever bonds after cure, but in Berkut's case, the skins were carbon so it was academic. If this is a concern, those sub surface bond areas could be left bare. Peel plying was discouraged for another reason. It was claimed that this would add weight because the added resin would be used to fill the peaks and troughs between each bundle of fibers in the cloth and if used in that way, there is no doubt there is a weight penalty. The original design calcs are based on the assumption that the top skin will be sanded flat, i.e. that half the bundles will be damaged getting down to the required condition for bonding and finishing. Then the micro finishing process is carried out, filling up the remaining texture and the transitions between layers of glass There is however, another way to look at peelplying. If the top layer is applied slightly rich resinwise, and then peelplyed three things happen. The first is that the surface finish requires little or no sanding prior to bonding, microing and much less filler. The second advantage is that any sanding does much less damage to the structural glass. The third advantage is that the glass bundles are pressed flat and by judicious squeegeeing most if not all of the excess resin can be removed from the layup. The savings in sanding when you are at an energetic and resource ebb are significant. One final caveat is to ensure that the peel ply has no untoward coatings which could degrade the final bond. Hope this clarifies the issue. John -----Original Message-----
From: Cash, Gene [SMTP:CASH@...] Sent: Thursday, December 07, 2000 5:09 AM To: 'Q-LIST@...' Subject: RE: [Q-LIST] Fiberglassing Techniques I read something ages ago saying that Rutan (RAF) clearly poo-pooed the practice of sprinkling microballoons on wet lay-ups because it would tend to pull up epoxy and starve the lower layers of needed adhesive. For the same reason the practice of laying peel-ply over the entire wing surface lay-up was nixed. There doesn't seem to be an easy way out of the surface finish work. Gene Cash -----Original Message----- To unsubscribe from this group, send an email to: Q-LIST-unsubscribe@... Quickie Builders Association WEB site http://web2.airmail.net/qba321tm/q-page1.html |
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Fuel System Plumbing
kdvd@...
Hello everyone,
Kurt Van Dyke here. I haven't seen or talked to some of you guys in a while; Been busy building (yea right). I just found the site and I think it's the right place for some answers. I've been working hard on the Tri-Q200 and I have a couple questions (poll) I need to ask anyone who will reply. I am about to purchase all the parts for the plumbing (of an 0-200)(yes there still area few guys in the building phase who are dragging up the rear) and I wanted to know what everyone is running for : A) Fuel line size to-from the header and to through the firewall-to- engine? (I planned 3/8 allthe way - hard plumbed to the gascolator; overkill?) B) Where did everyone mount their fuel pump? C) where the hell do you put the emergency pump bulb if you are flying center stick? D)Is there anyone else out there that does not have a lot of faith in the cheap check valve in the pump bulb and has added an in- line check valve? E) Who's running in-line fuel filters before the pump, type? I have dreaded (procrastinated) the fuel system construction because, inevitably, I always seem have leaks when plumbing anything and there's nothing as fun as leaking explosives. I am not convinced that the integrity of the epoxy tanks will work without leaks the first time, so has anybody got advice to a seal-tight tank? I looked through all the newsletters and I am at the end-of-the-road with these questions left. Thanks for everyone's advice and I envy all of you who are flying (don't you just love to remember the "good ol' days of builing?") Betcha' forgot, huh? See ya Kurt kdvd@... |
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Re: Fiberglassing Techniques
Hot Wings
Just another opinion and a look at this from a different perspective - It's
left up to the reader to glean the truth. << 1. When sanding the shell, the difference in resistance to sanding between micro and foam is so great that the moment you break through the shell you have stuffed the contour and you are up for a repair anyway. I have not found this to be a problem unless the core was way too wavy to start with. If you sand only until you see a blue (or orange) pattern appear that looks like a dried up lake bed you still have several thousandths of micro left to keep your sanding block from digging into the foam. 2. You deny yourself the advantage of a chemical bond between the micro and the glass This is a moot point as a clean and sanded epoxy/epoxy bond is many times stronger than the foam/foam bond. The foam will ALWAYS fail first. 3. Foam is much, much easier to sand than micro therefore it is much easier to get a near perfect core with bare foam. ( i.e. long sanding blocks and sanding templates) Its so much easier to sand that it takes a really light touch not to damage the foam. I find that it takes me less time to sand a good contour with the "skin" even though it takes more "work". 4 The near perfect contour you go to such lengths to generate is inevitably disrupted the moment you lay-up any varying thicknesses of glass on the foam surface (unless you read ahead and make the appropriate allowances in the foam) so you are up for surface filling whichever way you look at it. Aren't we supposed to "plan ahead"? About the only area where I have found a problem with loosing the contour is on the leading edge of the wing where lay-ups over lap. Other than this after several layers of (carefully laid) glass have cured a long block will still evenly mark the surface just as it did before the glassing. If the lay-ups are done carefully many times all the prep that is needed is a sanding with 220 and a coat of primer/sealer. 5 It doesn't make a great deal of sense to make one simple operation into two or more for no overall benefit. >> Very true - But I do see a 2 very real over all benefits. 1); I think you get a STRONGER wing because as we all know the limiting factor is the compression strength of the materials we are working with and I find the glass fibers to lay much straighter when layed up on a flat and firm surface rather than over some squishy micro which always seems to move around when working the lay-up. And 2); I find it requires less over all work to get to the finished product. If in doubt - do it by the plans. We know they work. "Think outside the box - but fly in the envelope" <A HREF="http://hometown.aol.com/bd5er/Qpage.html">Q-2 page</A> Leon McAtee |
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I'm back
Michael D. Callahan <micallahan@...>
Hey guys,
I'm back in order now after being OTS for a week. I had over 175 messages by the time I finally got my mail today. Last Thursday my friendly neighborhood volunteer moving service (BURGLARS!!) paid me a call and removed some items they saw as burdensome around my house. Among these were my monitor, keyboard and trackball, but they left my CPU!! I guess the wadded mass of cables connecting my flight simulator yoke and pedals involved more work than they felt warranted. Moral of this story is... screw your cables down tight and wrap the long ones madly around the desk. It may not save everything, but at least I still have all my info! Bad news is that I lost some items that were not very valuable financially, but were sentimentally priceless. Good news is that a lot of what I lost was not being used, not going to be used, but I just couldn't bring myself to sell it; I have insurance at least. Such is life. Important point in this is that upon reading my homeowners policy carefully it states explicitly that airplanes and airplane parts ARE NOT COVERED!! This means Q parts. Funny enough models are covered, wonder if they'd believe it was a 99% scale?:-) My plane parts are all safely stowed where I work, but what about yours? Are your mags and other accessories sitting in a drawer in you toolbox? Just something to consider. Mike C. |
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Re: Questions questions
L Koutz <koutzl@...>
Paul
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I found your E-mail to be informative. And I am glad you took the time to write. You obviously did MORE than hear the various techniques on building and then form an opinion of what system to use based on: your prejudice the presenter's glowing persuasive arguments or the phases of the moon. I think back to when I was a kid and was persuaded DC9's will fall out of the sky tail first if the engines quit. This was told to me in no uncertain terms by someone who I thought was knowledgeable; only to find out he was full of B.S. So it IS important to listen, then test opinions to make sure you know fact from fiction. You went that ONE step more, you tested. That IS important. It might be nice to attach numbers to the tests results but then again there are a lots of variables in testing that can skew the results. The qualitative results you reported are very informative and since we aren't engineering a new wing or something. Numbers are not really necessary because we only want something just as good structurally.I have found through the experience of redoing other builders fiberglass work that secondary bonds ARE a problem and a good, knowledgeable builder takes the time to prep the surface for a bond. So it seems either method of glassing over foam is OK if done properly. Think about the plans, they were created over 20 years ago, they worked, and if built per plans you had a sound structure. The only structural failures I know about in Q's were voids in main wing foam created by a repair, foam laid up in horizontal layers with no bond between them (not per plans), and overstresses (hard landings). Anyone know of any others? Now 20 years later there ought to be other methods of glassing over foam that is just as good structurally. Why aren't we discussing them? This brings me to the reason for writing this E-mail! Paul, and probably other readers, feel like if they ask a question, sound out an idea, or even write an E-mail. They are going to get their head chopped off (wire brushed) because of what they write. If a person writes something, that, in YOUR OPINION, is dumb. Then there ARE nice ways to inform the writer that they need to rethink their opinion because of your facts or observations. This shows that you have class, are knowledgeable and are really interested in trying to HELP other Q's builder get their creation in the air. So it would help if posters on this forum remember: there are always going to be people reading these messages that have more knowledge, experience, cleverness than you and there will always be people with less. If everyone would practice that philosophy in our E-mail maybe we could draw out more of that knowledge, experience and cleverness and impart it to those with less. Then we might have more Q's flying!!!! Isn't THAT what this forum about? Larry ----- Original Message -----
From: Paul Buckley To: Q-LIST@... Sent: Wednesday, December 06, 2000 7:08 PM Subject: Re: [Q-LIST] Questions questions Hi Dave There was a lot of discussion at least 10 years ago about the pros and cons of allowing the micro to cure before laying up the glass. It was generally thought to be a good idea as it allowed for the fine contouring of the airfoil and gave a hard and firm surface on which to stipple and squeegee out all the excess epoxy. It also eliminated the possibility of getting micro in and between the glass plies, and it was much easier and faster to lay up the glass. On the down side, it was thought that the bond between the cured micro and the glass, being mechanical rather than chemical, would not be as strong. As I could also see that the technique would separate the wing skinning process into two parts, thereby allowing for a better production timescale, it appealed to me, so I built a small section of the airfoil in order to test the adhesion of the glass to the cured micro. Of course, the subsequent test was not in laboratory conditions, but I gave the cured section to a sceptical friend [who used to work for "Moller Industries" in San Diego, producing top secret glass and carbon fibre research vehicles for the government] with the instructions to try and delaminate the plies by flexing and bending the part. The conclusion was that the bond between the glass and the micro was, to all intents and purposes, indestructible, the foam proving every time to be the weakest link. We also tested a section [built at the same time] using the "glass on micro slurry" technique, and concluded that it seemed no different to the "cured micro" airfoil. Of course it should be emphasised that the cured micro was very carefully abraded with reasonably course production paper over its entire surface, using a three foot spline, and great care was taken not to contaminate the resulting surface, thin rubber gloves being worn at all times to avoid contamination by skin oils. I went on to build three wings by this method, and found the process, and end result, extremely satisfying, but, of course, this was just me and each individual should make up his/her own mind as to the viability of any alternative construction method. ......but doesn't the rest of the aircraft rely on a mechanical bond between component parts, even the firewall area, which must be the most highly stressed area of the whole aircraft ? I rest my case.........and await the flack ! Paul Buckley |
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Hard Shelling
Jon Finley <finley@...>
David,
I dug through my CSA's last night but could not find the info that I mentioned yesterday. I suspect the discussion was on one of the mailing lists rather than CSA. Sorry about that. Jon |
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Re: Fw: CAM 125
KTSENYA2@...
Thank you for your assistance.
I believe the canard is the GU airfioil, as it has vortex generators attached. The Engine is a Revmaster 2100 DQ and seems to have been sitting for some time. I anticipate that it will return it to Revmaster in nearby Hesperia for teardown and overhaul, which I'm told is about $1000 to do. The airframe has about 100 hours on it as best I know. There's not too much history to review. The logbooks basically reflect the build process, the original sign-off, fly-off time and regards some damage incurred during taxi, which seems to entail repair of the wheel pant leading edges the cowl and the canopy (Sounds like it flipped over? No mention of any damage to the tail)... But the overall condition presently seems fairly good. First impression of it is not too telling as it's been stuffed into the back of a hanger where it's been for quite some years, and is now covered by a layed of dust/ dirt. The painted surfaces looked good and I'd sum up workmanship at 7 or 8 on a 10 scale. The plane is about as complete as can be, has a reflexor and is dissasembled in pieces waiting to put back together. Most of the instruments are there, controls, baffling, cowling, prop, but no radios (not surprisingly). This plane was a part of a package deal which consisted of assuming the lease on a hanger and everything, including three planes in it. The circumstances surrounding the present owner's aquisition of these (I'll explain) planes seem odd. The plane was born in Nebraska. Two years later it was sold, and lived near Newton Ks. Shortly after that sale the taxi damage occured. Not long after that, it was sold again (now 1987). The owner flew it from Kansas to Calif (Ramona) where it is today. The (1987) owner was a KLM pilot who owned this plane as well as another Q2, and a Bushby Mustang. The Mustang was/ is flyable, the two Q2's were not. Strange circumstances surround the somewhat hasty departure of this KLM pilot who, was as I am told lost his Visa or work permit and his right to reside in the USA expired. He priced the 3 planes and the contents of the hanger to "quickly sell" ($15,000), which brings it to the present owner, who is interested in selling one of the Q2's. He is readying the other Q2 for himself. He wants $4500 for the Q2 I'm writing about. He has even been (apparently) gracious enough to offer me space in the hanger to get it into flying condition sharing 1/3 rent. I suspect that in its condition I could probably ready it to fly in 6 months barring discovery of anything serious and long term requisite. I am told that the worst of this plane is its ground handling and there are some remedies to better things in that regard, but in the air is a joy to fly. I am 5 foot 11, weigh about 190. Will the Revmaster be sufficient power for me? The EW is 565. Is this heavy, about representative of what's flying, or light? The SN is 2260 The tail # is N3257Z Do you know anything of this particular plane, and how can I post this message to the entire group for maximum exposure? Thank you for helping out and any additional input is appreciated Bob Sankey Encinitas, Ca. 760 942 9727 |
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Re: Fiberglassing Techniques
jtenhave@mets.mq.edu.au <jtenhave@...>
Dave,
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there are a couple of reasons why the hard shelling technique is not optimum. They are: 1. When sanding the shell, the difference in resistance to sanding between micro and foam is so great that the moment you break through the shell you have stuffed the contour and you are up for a repair anyway. 2. You deny yourself the advantage of a chemical bond between the micro and the glass 3. Foam is much, much easier to sand than micro therefore it is much easier to get a near perfect core with bare foam. ( i.e. long sanding blocks and sanding templates) 4 The near perfect contour you go to such lengths to generate is inevitably disrupted the moment you layup any varying thicknesses of glass on the foam surface (unless you read ahead and make the appropriate allowances in the foam) so you are up for surface filling whichever way you look at it. 5 It doesn't make a great deal of sense to make one simple operation into two or more for no overall benefit. Hope this helps John -----Original Message-----
From: Dave King [SMTP:KingDWS@...] Sent: Thursday, December 07, 2000 8:23 AM To: Q-LIST@... Subject: RE: [Q-LIST] Fiberglassing Techniques |
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Re: Questions questions
Paul Buckley <Buckley@...>
Hi Dave
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There was a lot of discussion at least 10 years ago about the pros and cons of allowing the micro to cure before laying up the glass. It was generally thought to be a good idea as it allowed for the fine contouring of the airfoil and gave a hard and firm surface on which to stipple and squeegee out all the excess epoxy. It also eliminated the possibility of getting micro in and between the glass plies, and it was much easier and faster to lay up the glass. On the down side, it was thought that the bond between the cured micro and the glass, being mechanical rather than chemical, would not be as strong. As I could also see that the technique would separate the wing skinning process into two parts, thereby allowing for a better production timescale, it appealed to me, so I built a small section of the airfoil in order to test the adhesion of the glass to the cured micro. Of course, the subsequent test was not in laboratory conditions, but I gave the cured section to a sceptical friend [who used to work for "Moller Industries" in San Diego, producing top secret glass and carbon fibre research vehicles for the government] with the instructions to try and delaminate the plies by flexing and bending the part. The conclusion was that the bond between the glass and the micro was, to all intents and purposes, indestructible, the foam proving every time to be the weakest link. We also tested a section [built at the same time] using the "glass on micro slurry" technique, and concluded that it seemed no different to the "cured micro" airfoil. Of course it should be emphasised that the cured micro was very carefully abraded with reasonably course production paper over its entire surface, using a three foot spline, and great care was taken not to contaminate the resulting surface, thin rubber gloves being worn at all times to avoid contamination by skin oils. I went on to build three wings by this method, and found the process, and end result, extremely satisfying, but, of course, this was just me and each individual should make up his/her own mind as to the viability of any alternative construction method. ......but doesn't the rest of the aircraft rely on a mechanical bond between component parts, even the firewall area, which must be the most highly stressed area of the whole aircraft ? I rest my case.........and await the flack ! Paul Buckley ----- Original Message -----
From: Dave King <KingDWS@...> To: <Q-LIST@...> Sent: Wednesday, December 06, 2000 6:28 AM Subject: [Q-LIST] Questions questions Hi All |
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Re: Fiberglassing Techniques
If you use denatured alcohol to thin the "dry micro" for finishing, the
foam will not erode. My 2 cents worth. Bruce Crain On Wed, 6 Dec 2000 12:26:46 -0600 "Jon Finley" <finley@...> writes: Hi David,________________________________________________________________ GET INTERNET ACCESS FROM JUNO! Juno offers FREE or PREMIUM Internet access for less! Join Juno today! For your FREE software, visit: http://dl.www.juno.com/get/tagj. |
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Re: Fiberglassing Techniques
Dave King <KingDWS@...>
Hi
When I wrote the question I was using my little Tosh notebook, little keys big fingers, slow typing. I'm back on my regular machine so that means lots of typlexia and bad spelling...;-] What I didn't add to the original question was that I was looking at this with an eye towards getting a perfect contour to start with and if this helps with the final finish ie more accurate or less finishing required etc. Oh yea, as I recall the weight penalty on large items (wings, winglets) wasI take it this is Ez sized wings? I don't have CSA but I did a search through my cp's and couldn't find a reference in there (I'm sure it is somewhere). From what I was told it was supposed to result in a lighter layup as the cured micro layer sealed the foam from any fresh epoxy getting into the pores. I can see how it might come out the same weight or heavier but wasn't too sure about lighter. I have seen layups use both techniques. The Q plans call for the micro toI hadn't heard it called hard shelling so I'll do some searching on that. From the info I had the core was finished then micro slurry applied and squeeged normally but allowed to cure. Then any dimples dents etc are filled, ie scuffed land then filled and allowed to cure. Then the micro 'd core gets sanded down using reversed templates to check contour. The rest of the prep is the same as a glass to glass. Then the cloth gets laid up as per normal. From what I saw of this it should give a good base to start with and if the layups are done with care the final finish is more accurate. Yes, the quality of the bond was an issue. The conclusion was that theIf the foam came up then its definalty failing in the right way. Sounds good. To me it seems that it couldn't be any weaker than a glass to glass bond done over time. ie one layer applied after the epoxy has cured. My personal conclusion (from reading and doing a hard shell layup) wasis so much easier.Thats interesting to as I kept thinking it would be a bit more work in the long run. If you are a "follow the plans" guy, disregard everything I have said andPLANS??? We don't need no steenkin plans!! (quickly donning flame proof underwear) Cheers Dave |
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Re: Fiberglassing Techniques
Jon Finley <finley@...>
Hi David,
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I don't recall what RAF had to say about it, I would certainly think one of those guys asked. It was at least a couple years ago. I will see if I can lay my hands on them tonight and let you know. I use the "bubble sprinkle" somewhat differently than maybe what you are thinking. I use it to eliminate the glossy surface on the layup so that the dry micro applies easier and has a surface to grip. So the only sanding that is minimized/eliminated is that required to remove the gloss and create something for the micro to grip, filling is still required. With this in mind, I believe that the bubbles should be applied just before the epoxy tackiness goes away and that only a very small quantity of bubbles be applied. The goal is is to have the bubbles stick but not absorb epoxy. I usually sprinkle the bubbles on, rub it in with my gloved hand (if this helps understand when I do it - the epoxy is pretty set), and then brush off the excess bubbles (the ones not sticking). I have never done it with a large/structural layup (haven't had the opportunity). I'm of the opinion that if the layup isn't dry and the builder waits until the right stage, it is ok. I can imagine someone pouring a couple gallons of bubbles on a wet layup, obviously this isn't going to work real well (probably result in an extremely dry layup with a ton of sanding needed (before throwing away)). The big problem with doing this is that layup inspection is very difficult after applying the bubbles, you really need to inspect the layup before applying the bubbles. As long as we are talking about stuff that is "wild & crazy".... I also use alcohol to thin my dry micro. I mix up the micro as dry as possible, add a small amount of alcohol (I do it by eye, but it is probably a tablespoon or so for an 8-12 oz cup of micro), and then add more bubbles. The result is an extremely light micro that is easier to spread. Yea, there was a big debate about this too (does the alcohol mess with the chemical properties of the epoxy, etc...). All I know for sure is that all of the airplanes that I know were finished this way and they still look fine. Jon Finley Q1 N54JF - 1835cc VW Q2 N90MG - Subaru EA-81 DD Turbo Apple Valley, Minnesota -----Original Message-----
From: David J. Gall [mailto:David@...] Sent: December 06, 2000 11:38 AM To: Q-LIST@... Subject: Re: [Q-LIST] Fiberglassing Techniques Jon, I must have missed this item. Did RAF ever endorse the hard-shell procedure? If not, did they ever renounce it? Either way, can you narrow down the approximate year in either the CSA or RAF newsletter so I don't have to dig so deep? On a related issue, I do recall the big debate over sprinkling micro on the surface of a still-wet layup to save on post-cure filling and sanding. Do you have an opinion on that technique? Thanks, David J. Gall |
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Re: Fiberglassing Techniques
Cash, Gene <CASH@...>
I read something ages ago saying that Rutan (RAF) clearly poo-pooed the
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practice of sprinkling microballoons on wet lay-ups because it would tend to pull up epoxy and starve the lower layers of needed adhesive. For the same reason the practice of laying peel-ply over the entire wing surface lay-up was nixed. There doesn't seem to be an easy way out of the surface finish work. Gene Cash -----Original Message----- |
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