Marc Zeitlin

Nothing, because there's no such thing as "Aircraft" epoxy or "Marine" epoxy. There are epoxies that designers have chosen based on their properties to ensure that the specifications of the device in question (aircraft or boat) will be met. If you use an epoxy that was not approved by the designer, then maybe those specifications won't be met, and you may either fall into the water or out of the sky. Since you're interested in LE's or COZY's, there is a clear list of approved epoxies that can/should be used, and you should pay attention to it, particularly to the fact that the best epoxy for the strakes/fuel tanks is the EZ10/87 due to its fuel resistance capabilities. There are reasons NOT to use particular epoxies as well - the West 105/205/206 are NOT approved due to the low pot life and high exotherm probability on structural (read thick) layups. In the grand scheme of things, the cost of the epoxy is a tiny percentage of the total cost of the aircraft - don't skimp here.

I hope that you are not anodizing any structural aluminum parts - only cosmetic ones...

https://www.aircraftspruce.eu/composite-materials/fiberglass-cloth-tape/cloth/rutan-fiberglass-cloths.html

So..... how did you install a COZY MKIV strut / electric gear on your plane if you didn't have the COZY MKIV plans to work from? In any case, if you don't have a set of plans, find a COZY builder/flyer somewhere near you in OK (yes?) or TX or KS or NM, etc. and take a look at theirs. Or spend $500 and buy them from ACS, or find someone with an electronic PDF copy of the Aerocad plans for Chapter 13 (hint) and ask them (via private email) to send you a copy (via private email). The Aerocad plans are functionally identical to the COZY MKIV plans.

Does it occur on the ground at 2K RPM? If you bring the engine to idle in the air, then accelerate again, does it happen at 2K RPM? What's "low frequency"? Do the canard tips oscillate at the low frequency? Is it only a "buzz" in the seat of your pants? How pronounced is the vibration? Bad enough that you can't read the instruments? Have you looked at the engine mount rubbers to see if they're in decent shape? Is there something loose in the airplane that's flapping around? As you change IAS, does the frequency of the vibration change? If you decelerate through that speed range at 1800 RPM, does the same thing happen? If you decelerate at speeds below 140 mph ias but at 2K RPM, does the same thing happen? If you accelerate through that speed range at any RPM, does the same thing happen? Have you asked Chris or Burrall about this? They've got about a zillion hours in that plane together - I'm sure they know it like the back of their hands... Without feeling it, hearing it or seeing it, it's VERY hard to say if there's even anything abnormal, much less what it might be...

Unless the POH for the engine or the airplane states a restricted area for continuous operation, no. Generally, RPM restrictions are put onto engine/prop combinations, not an engine alone (although there are always exceptions). And since there's no way for the designer to have a clue what prop you're going to have, Burt didn't put any restrictions on RPM for the O-200 on a VE. OK, so precision in language will help a great deal in diagnosis. We couldn't possibly begin to discern what an airplane that "feels not happy" might mean in the context of vibration, aerodynamic behavior, oil usage/leakage, canard/wing/winglet motion, control system forces, or any of the other things that might not be optimal on an airplane. Nor what "210 to 140" means. IAS? TAS? Kts? mph? Descending? Climbing? Precisely what are the symptoms, and under what circumstances, and how do they differ from what the airplane does in other circumstances?

Good enough. I'm slightly suspicious of the values noted in the document - they seem high for fiber lock nuts. But I've never done a study, so I can't say for sure. You would add some torque based on the value the torque wrench measures before the bolt/nut is tight. The "tare" torque of lock nuts is actually pretty low after the first installation. Even for metal locking nuts, the MAXIMUM tare torque for 1/4-28 nuts may be around 30 in-lb for the first install, but then drops to around 2.5 - 5 in-lb for subsequent installs. See Page D-38 of this document: http://tinelok.com/wp-content/uploads/2013/09/IFI-100-Prevailing-Torque-Locknuts.pdf for more info. The fiber locknuts will be lower in "tare" torque, so I'd say to ignore the tare torque if the nut's been used before and still can't be turned by hand, and use the torque wrench measured value of "tare" torque on the first installation. But it certainly can't hurt to see what torque is required on the torque wrench to turn the nut/bolt prior to getting tight, and then add that value to the required torque value to get the necessary reading on the wrench. For further confusion, Table 7-2 of Chapter 7 of AC-43.13-1B gives minimum prevailing torques (tare) for AN365 nuts, but only for nuts larger than 7/16" (go figure). But the 7/16" nut has a minimum value of 8 in-lb, which would lead me to believe that the AN4 (1/4") nut would be in the 3 - 5 in-lb range, as indicated above. So, if you're shooting for 50 - 100 in-lb as a range, and you set your wrench to 80 in-lb, you can't go wrong - you won't break anything and you'll have more than enough torque no matter what the prevailing nut torque or nut type is. Is this getting any clearer? :-).

Good question. Because on further reflection, although the canard lift tab bolts are in single shear, part of their purpose it to put substantial friction force between the lift tab and F-22 in order to transfer the lift loads. Because, if the F-22 was build correctly, there's an AL bushing that the bolt/nut squeezes (and the plans call for an AN4-12A bolt, not a 13A, so be careful that you're not bottoming out the bolt threads) you can't crush the foam/fiberglass structure of the F-22 bulkhead, I think that it's better to go tighter than just a "bolt in shear" level. But I don't think that there's anything unsafe about the 50 - 70 in-lb range - you just get more margin if you go to the maximum capability of the bolt and nut, which is 100 in-lb. I'm sorry for revising my thought process as I went along and confusing you. As long as you've got more than 50 in-lb on the bolt, you'll be safe. Sadly, the plane (VE, LE, COZY) don't spec a torque for these bolts, which are just about the most important ones in the plane :-). So that table you found is 1/2 of Table 7-1 in Chapter 7 of AC43.13-1B (downloadable from the FAA, and an indispensable reference tool). It's only the torque levels for bolts in shear - it doesn't show the maximum allowable torque limits for bolts in tension, which is where the 100 in-lb. comes from. Unless there's some good reason to use some random document found on the web (like the AC doesn't mention the issue and there's no other master source), AC43.13-1B is the canonical document for aircraft maintenance. You won't crush the structure of the VE if the bushing was installed during the build process, but you WILL deform the bolt, possibly stripping the threads and/or stretching the bolt. 100 in-lb is 8 and a tiny bit ft-lb, so yeah - 10 ft-lb (not 10 ft/lb) is way too much and will harm the bolts. Sorry for confusing you and changing the story midstream. Basically, in this case, anything between 50 in-lb (lowest # to use for bolts in shear with an AN365 nut) and 100 in-lb (highest # to use without harming the bolt/nut) will keep your canard on the airplane safely. Which is why I rarely use a torque wrench to install the bolts - once I know by feel with a certain wrench how much 100 in-lb is, I just go somewhat less than that, and call it good. Hope this is clearer than mud.

Unless there's corrosion, plating being worn isn't a problem, but obviously new bolts can't hurt anything. I'm going to guess that what was on there was AN364 low profile lock nuts, rather than the AN365 full height nuts. Not the right nuts, and I certainly recommend the full height nuts. Obviously it worked, but still... The right nuts allow you to use the full torque specification for the bolts, which the low profile ones do not. in-lb or ft-lb? 40 in-lb is almost nothing... More is not better. If there's a spec, and you used it, why would you tighten more? What spec did you use? Personally, I like nut-plates for the ease of installation/removal, but there's nothing wrong with nuts in this situation. Just right is whatever the torque spec is. From Table 7-1 in Chapter 7 of AC43.13-1B, assuming the bolts are primarily loaded in tension, you'd use a torque spec of 100 in-lb (~8 ft-lb) for the AN365 nuts. And you don't have to replace a locking nut just because you used it once - basically, if you can't screw or unscrew it onto the bolt with your fingers, it's got enough residual locking torque to use again. Believe and use the specifications - don't try to do "more". New bolts and the correct nuts are great, and it's good that you're being careful and thoughtful. Always better than the alternative... And I agree with Kent about the wide area washers under the bolt heads, but I've never seen an issue with AN960 washers, so that's just more conservativism.

Long-EZ plans are almost useless for a Varieze - there's no point in downloading them. The pitch control system is different, as are many different sections of the plane. You should have gotten the plans from Chris or Burrall when you purchased the plane, but if you didn't and they don't have them to give you, then I can share a set of PDF plans sets with you (since RAF no longer cares about copyright infringement and has essentially put all of their documentation into the public domain).

Well, I've been to Kanab every year for the past bunch, so it's certainly possible. Great - I was wondering where Burrall's plane had ended up. And it is certainly a learning experience. Good on you for flying Avantis - Maybe you could bring one to Kanab this year and give rides :-). Uggghhh. I won't give my whole spiel on my position on MGL equipment. I just hope you don't ever plane to fly in IMC. But their servos should be essentially the same as everyone else's. Most folks mount the roll servo on the firewall, and have it push/pull one of the pushrods, and the pitch servo will usually go on the side of the fuselage forward of the IP and push/pull on the pitch pushrod from the intermediate belcrank (which only exists on VE's) to the canard belcrank. But there are many variations. Do you not have a copy of the VE plans? You really need to have a set, if you're going to own and maintain the plane. Page 19-6, figure on the lower right, has the answer to the previous question about quick disconnects and also indicates what clevis pin and safety pin to use. They call for an AN393-19 clevis and an AN416-1 safety, and they say to install it through the lower end of the pushrod, just fwd of the intermediate belcrank. Page 19-5 shows how the whole assembly goes together.

AC43.13-1B, Chapter 7, table 7-1 lists torques for different bolt sizes and nut types. For tension nuts (the thicker ones, which are hopefully what you're using) it's 50 - 70 in-lb. But like Kent says, get a short handle wrench and make it "tight". You can calibrate your feel by tightening a few bolts with a torque wrench to 60 in-lb, then putting the short handle wrench on them and seeing how hard it is to just barely tighten them further. Then keep doing that. Assuming you already have an AL rod in the tubing and are using the AN-3 bolt/nut combo now, you can certainly do what Kent says - it's standard in the COZY. Or even if you don't - it's relatively easy to install per Kent's instructions (use 1/8" solid rivets and peen the head appropriately). Or you can just disconnect the pushrod from the intermediate belcrank just forward of the IP - it's relatively easy to reach, and you don't have to modify or install anything. Do you have canardian resources near you in UT? When you need a CI, get in touch...

I don't understand your math... Even assuming your stated capacity of 45 gallons and a burn rate of 4 GPH, that's 11 hours of endurance and ~1100 NM of range. But in fact, Long-EZ's (standard ones) hold about 52 gallons of fuel and even with an O-320 burning 7 GPH at 160 - 170 KTAS at 9 - 12K ft. would have a range of about 1100 NM - no reason to stay in the air for 11 hours to go that far. If one throttled back to best L/D speed (and no-one ever does that, because you didn't get a 170 KTAS plane to putz around at 95 KIAS) you can get up to 1300 NM range - maybe a bit more. Now, you can fly at the Carson speed (give or take 120 KIAS) and still get really good TAS's if you fly high - in the mid to high teens - and get some real range without staying in the air for weeks at a time. Hell, I've flown my COZY MKIV, at normal cruise speeds of 140 KIAS and 167 KTAS, burning about 8.5 gph and flown 1100 NM and landed with 30 minutes of reserve. Long-EZ's will only do better.

Interesting - I bought mine from Brock (Wilhelmson sell them now) and they're steel. But you're right, the COZY MKIV plans don't call out the material (assuming, I suppose, that you'll buy them from the approved supplier). See: http://www.eznoselift.com/index.php/price-list I can't imagine why Nat would have removed that piece of information from the plans - who was it hurting or confusing? But yes - if I were you, I'd install steel versions on your COZY, just in case... AL is only 1/3 the stiffness - hence the buckling of the sides under stress. And I'd do it before the next flight.

Well, yeah, but that's not the root cause of the failure. A rod-end failing would not cause NG-3 and NG-4 to rip off of the nose gear strut. He's got it backwards - your apparently AL NG-3 and NG-4 (which both should have been 4130 steel per page 13-3 of the LE plans, NOT aluminum) bent and collapsed due to one or more hard landings (you can see that the bolt that goes through the NG-3/NG-4 and rod end, with the spacers on it, also bent from the impact) and when the NG-3/NG-4 substandard pieces bent/failed and ripped off the gear strut, the rod end THEN broke due to a side load. The rod-end cannot have a side load, even from enormously bad landings, due to geometry unless the NG-3/NG-4 have already deformed in a major manner. Having someone who knows little to nothing about the aircraft in question try to perform a forensic analyses is nigh on useless. I'm sure the FAA doesn't give a crap about the root cause of this failure, since it was neither an accident nor possibly even an incident, but you could fill them in on the actual analysis presented here if you want or if they ask. Good luck on the repairs - you're lucky there wasn't substantially more damage. Emons should be able to make the parts you need. Ask him about belleville washers for the prop, while you're at it, if you want a fireworks show :-).

There is no way to "recognize" it from an on-line pic, and the analysis required to determine what it actually is would cost more than just buying the right stuff... I'm glad that you won't use it unless you get proof of its acceptability.

Yeah, you're missing my point :-). Some folks WANT to get the RC for an airplane, so if the airframe conveniently "disappeared" and then "parts" were salvaged to build a new plane, the new plane could be AC'd, registered and an RC could be issued. Legal? Eh. Does it happen? A lot, as you pointed out. In either case (at least if you want updated OL's, depending upon what FSDO/DAR you use) you'll still need an inspection for the AC/OL's, and even if you didn't, the small cost of the inspection is worth a lot to folks if they can get an RC on an otherwise "brand new" airplane. Whether the current owner knows what the registration of the airplane may or may not have been previous to his acquisition, my working assumption is that he's representing this airplane as having never before BEEN an airplane. But a phone call would determine that, if I gave a FF...

You have some random material that you think might have been intended for an airplane but you don't know. It's not the same as the approved material. You don't know what it is, you don't know it's properties, you don't know whether they compare well to the material that's supposed to be used, you don't know if it's got a different finish, you don't know if it's ever been wet, and you want to know if you should use it for the single most important structural component of a device you're going to lift your family to 10K ft above the surface of the earth within. Could it work? Sure. And you could use hardware store bolts instead of AN bolts, and elmer's glue instead of epoxy. This is kind of that, unless you can determine what the properties of the material you've got a roll of are. The total cost for the approved material (not counting shipping) at $1.85/yd for the 282 yds needed for the COZY MKIV, with a 50% margin for extra and losses, is $782.55. I think you can discern what my recommendation would be.

I agree - it's fairly obviously been a flying airplane that was built a long time ago, and not advertised as such. The interior (as you state) and the residual paint on the ends of the main spars give it away. Depending upon how honest one was, this would complicate getting the RC ONLY if the new owner NEW what "N" number the plane had been issued previously and tried to re-register it with that "N" number AND the RC had been issued for that plane. This sort of nonsense happens all the time - someone buys a basket case and makes believe that they built the whole plane. How would the FSDO/DAR know? I do not, in any way, advocate this sort of monkey business, but it happens... There's no issue getting the AC as EAB either way, though, since a VE is obviously a plans built plane and there's no evidence that it was built professionally - the new owner just has to sign the affidavit of it being amateur built. What would worry me, though, is that if the current seller isn't telling the whole story of what the plane is (another thing that happens all the time) then what else are they not telling you?

Work gets in the way of every damn thing :-).

You didn't stop by!

What Turboprop? There's no mention in the ad?

Here's what the current owner told me: "He said the builder acquired the wing spar and fuselage already complete by someone who started the project. The builder then told him that he used the vinylester throughout the rest of the project." I'd say that's a pretty good indication that vinylester resin was, in fact, used. Given what Gary Hunter says about Vinylester curing in thin layers (using standard epoxy techniques) quoted by Kent in post #146 above, I would argue that this plane is a candidate for a chainsaw and that it's good for parts only (where parts is anything OTHER than the structure). It MAY be worth buying, given that, considering the asking price. I certainly wouldn't fly in it. I do not, for the life of me, understand why people do things like this... 5 - 10 years of work for nothing, to save what - $300?

For those of you not on the COZY or Canard Aviators mailing lists: Tim Fisher has posted the dates for the Canards West Fly-In at Columbia Airport (O22) - it will be June 1st through June 3rd. See: http://www.canardswest.org/ for more information. To contact Tim about the event or to volunteer your services in some way (driving folks to and from the campground or into town; presenting on Saturday, etc.) he's available at: 209-996-9919 t.fisher13@comcast.net for questions/comments. Hope to see you all there!

No. Sure. Happens all the time. Especially now that many EZ's are getting on in years. Yes - a few have done so. You can raise the bottom of the IP a bit to ease getting large feet forward. Obviously, that will restrict how much crap you can throw at the panel, but one of my customers has raised the bottom a couple of inches and still has a pretty packed panel. POSSIBLE, but not recommended. There are a few folks that fly off of grass, but it has to be short grass on a long field, with a rearward CG and large main tires with high wheelpants. I have only ever met one person that didn't think that flying an EZ type aircraft was the best experience they've had in airplanes with respect to feeling like you're part of the plane. The feedback is not different - just better. It's light on the controls without being twitchy. I have one customer with a COZY MKIV who's an F-16 and F-35 test pilot who says that the COZY MKIV is his 2nd favorite plane after the F-16. So there's that. Sure, but you don't want to. Unless you're flying off of very short fields, the cost and weight penalties are severe. All it gets you is shorter takeoff rolls and higher climb rates - you generally get nothing, or give up a bit, on the top end.