Jump to content

Recommended Posts

35 minutes ago, jridge said:

I really liked this comment "Get the right nut, or re-cut a perfectly good part? "

The "right nut"? How does one choose a "right nut" for a defectively threaded part?

Share this post


Link to post
Share on other sites

FINISHING:  I have posted these pics before but I want them all in one post so here goes:  Pics 1,2 shows how I have lightly sanded the bare weave surface.  A light sanding with 36 grit in two directions is all that is necessary.  Even that may not be necessary--epoxy sticks!--but it gives me a warm fuzzy to sand a bit. Then it helps to prefill low and high areas on the wing and sand those pretty flat.  These areas are over the spar caps, the wing bolt reinforcement UNI, the trailing edge, and the like.  A prefill will make the Big Fill flatter.  Notice that I have also used micro on the leading edge of the wing and will round that off.  It is more bug-resistant than West 410 Microlight filler.

Then I do the Big Fill using West epoxy & slow hardener and 410 Microlight that I buy in a 4LB box (about $275).  Mix to a peanut-butter consistency.  Do not be stingy with this first fill--you want to get plenty of filler applied to make sure you fill all the big waves and low areas and can sand them flat without hitting the weave.  Any time you hit the weave, stop sanding.   You will sand a lot of the Big Fill off but that's what is needed.  I use a 6" rubber squeegee to spread it on fast, then transition to a 6" or 12" metal drywall knife that I heat with a few passes of a propane torch.  The heated drywall knife lets me even-out the filler with fewer ridges as the filler is beginning to get hard.  Try to get the filler pretty smooth; it makes sanding easier.  I wouldn't mix the filler as thick as you can, it will be hard to spread and hard to make even.

Pics 3.4 - Sand the Big Fill with 36 grit.  Inevitably, there are low places, pits and scratches left.   I mark low areas and pits with a Sharpie and _refill_the_entire_wing_again, this time with filler that is a little less stiff; it smooths better, does not leave as many pinholes and will make a consistent hardness for further sanding.  Cover the entire wing with filler and especially over the marked (low) areas.  It is a mistake to try to just spot fill.  The filler mixture will be harder or softer in spots and the sanding board will teeter-totter over the high filler and gouge low places.  Just refill the whole wing.  Sand (36 grit) until you just begin to see the marks under the second layer of filler, then I might follow up with 180 grit to remove the 36 grit scratches. 

The wing is looking pretty even now but there will usually be a few spots that require spot filling or patch filling.  If there are a substantial number of places, then it's better to mark them as before and refill the entire wing.    Now the wing is looking flat and about a 180 grit finish.

Pic 5 - Guidecoat:  At this point I spray a mist-coat of cheap black rattle-can primer and sand it all off to reveal scratches, pits and defects that need work.  In the photo, I have used more black primer than I needed but it sands off pretty easily.   If there are any big pits, I might put a dot of runny micro over them.

The Aluminum Bar Rub -  A wing can look flat but it's not.  A various times in the process I use a scrap piece of 18" X 1.25" X .5" stiff aluminum bar which I mark up heavily with a Sharpie and rub over the surface as if I was sanding.  The bar will leave oxide and sharpie smudges on the subtle waves and high spots the will need a little further sanding.  Sand those areas gingerly and rub again.  Eventually the smudges will blend together which means the wing is getting really flat.

pics 6,7  -  Epoxy wipes ("Cory Bird Method").  Now you have a nice flat wing with no big pits or scratches but plenty of pinholes.  Cory suggested 5 wipes of straight epoxy.  Squeegee-off the excess firmly and let it tack-up between applications.  However three wipes usually does it for me.  It will fill pinholes and 180 grit scratches.  Do not expect it to fill 36 grit scratches.  I find the straight epoxy will clump-up from surface tension (pics 5, 6).  Maybe there is a way to avoid that but I don't know one.  Wet-sand the cured surface with 240-360 grit and it will leave a pretty good, flat epoxy surface for an epoxy primer-surfacer or primer.  Over-sanding will remove the wipes and expose pinholes.

I have filled and painted 3 airplanes.  For wing sanding, I don't use anything more than scraps of 2X4 with sandpaper stapled to the ends you can see in pic 6.

 

 

 

IMG_0207.jpg

IMG_0206.jpg

IMG_0019.jpg

IMG_0018.jpg

IMG_0013.jpg

IMG_0008.jpg

IMG_0009.jpg

IMG_0017.jpg

  • Like 1
  • Thanks 1

-Kent
Cozy IV N13AM-750 hrs, Long-EZ-85 hrs and sold

Share this post


Link to post
Share on other sites

Just reading where a Cozy builder on FB mentioned buying PPG Deltron single stage for $506/gallon.   

I will just throw this out:  Consider using Nason (Axalta) 2K Fulthane at $186/gallon.  Nason is Axalta’s non-advertised brand—Nason doesn’t pay for NASCAR sponsorships and the colors are not as extensive.  It is likely a touch down in quality from Imron but the limiting factor for me is not the paint quality but the skill of the painter.  I have painted three airplanes and several cars with the Frost White and other colors.   I always have some sort of painter-induced problem—a run or sag—but a sag in $506 paint would make me cry like a baby.
 
 The Nason is good paint.  Unless you are an experienced painter in a proper booth, you will have runs, sags, orange peel, or bugs.  Below, a recent EZ paint job.  I have nothing against base/clear paints;  I just got started with single-stage and generally use that.
 
I generally paint outdoors in the Fall on a calm morning.  I find dust is not much of a problem (unless you are shooting for show-quality); I am going to buff-out the finish anyway.  I will stand by with tweezers for the occasional bug until the paint hardens up (30 mins or so).   When I have not painted for a while, I get rusty.  If you are not experienced, spray a car first to learn how.  Even though this was my 3rd airplane paint-job and I have painted several cars, on this EZ, I had an incident where I sprayed too heavily and got a horrendous sag the full length of the leading edge.  I ended up wiping-off a bunch of wet paint with a lacquer thinner-soaked rag and respraying.  That's a good reason to use $186 paint!  Usually it is a smaller problem.

IMG_0147.jpg

IMG_0155.jpg

  • Like 1

-Kent
Cozy IV N13AM-750 hrs, Long-EZ-85 hrs and sold

Share this post


Link to post
Share on other sites

Flew the Cozy the other day and had a bad miss   https://youtu.be/BZTiRdcURuI   🙂  

Lightspeed (Klaus) gets a lot of criticism for his bedside manner but his systems are relatively trouble free.  The nice thing is that they are pretty easy to troubleshoot.  I changed the plugs--no help--then replaced the plug wires.  One short wire had high resistance--about 300 ohms--should have been closer to 50.  They had 740 hours, Klaus says to change them at 500.  With new wires I sill had the miss so I did some serious troubleshooting per his new chart

http://lightspeed-aero.com/Manuals/Troubleshoot.htm

I learned that only one of my three VOMs will read the .6 ohm coil voltage.  The others read high but the coils were OK.  I found some loose screw caps on the sparkplugs and tightened them up.  Made sure the plug wires well well seated on the plugs and coils and it flew just fine after that so It could have had a loose cap or poorly seated plug wire.  8.5 mm MSD wires have a very thin spiral conductor around the core.  Frankly, I didn't know that until I watched a Youtube.  It would be easy to break the conductor if you weren't aware it was there.

BTW, right now I am using a variety of Autolite 386 and Bosch M8ACO 18mm plugs.  No inserts required.  I cannot tell any difference between NGK BR9ES plugs with inserts.

Another favorite Mitchell and Webb:  https://youtu.be/8HgejSCHRi8

 


-Kent
Cozy IV N13AM-750 hrs, Long-EZ-85 hrs and sold

Share this post


Link to post
Share on other sites

Just reading this accident where a CE-172 tried to takeoff from a 5737 elevation airstrip--St Johns Industrial, AZ KSJN--with 8600' density altitude, could not maintain altitude and crashed.  http://www.kathrynsreport.com/2020/05/loss-of-control-in-flight-cessna-172n.html?

I have been to that airport and a buddy of mine almost bought the farm there in his Cozy III, previously discussed.   https://www.canardzone.com/forums/topic/18661-kents-long-ezproject/?do=findComment&comment=65903       (disregard the bad info on runway width, it's a normal width)

The Cessna owner was from Michigan (630' elevation).  The airplane was near max gross weight with three people. The report mentions that the crew aborted the first takeoff attempt on the short runway and tried again on the longer runway.

The report does not say whether the crew leaned to peak power before takeoff but that would be my guess; it is a common mistake by a sea-level pilot.   Rough numbers:  at 8600' DA the engine leaned to peak can only make about 75% power.  At full rich it is making significantly less--maybe 65%.  The fact that the crew, flying an O-320 airplane at near max gross weight with 8600' D.A. initially chose the short runway, supports the presumption they probably took off without leaning.  The sloppy report does not discuss this.

What triggers a pilot to think "Hmm, I should lean the engine before I roll".   I have flown with pilots who never lean anytime at any altitude.  However if a pilot is in the habit of leaning on the ground and leaning to peak power for his altitude, he is more likely to make the connection between a hot day at 5737' elevation and the need to lean before brake release.

 

  • Like 1

-Kent
Cozy IV N13AM-750 hrs, Long-EZ-85 hrs and sold

Share this post


Link to post
Share on other sites

I did the majority of my flight training out of Colorado Springs, which is over 6,000 MSL. There wasn’t any such thing as a full-rich takeoff. Lowlanders could be a real hazard to themselves and their passengers at that altitude. 

Share this post


Link to post
Share on other sites

Here in NZ there are no (published) airfields above 2,500'. All pilot training teaches 'full rich for take-off'. Luckily we don't get many high-density days either, so pilots here get away with it.

But there are regular issues with fouled plugs etc. Guess why!

One should never assume that obtaining a license is the end of the learning process. That only ensures you have the essentials, there is much more to learn, and generally once you get a license, that is entirely up to the initiative of the individual pilot.


Aerocanard (modified) SN:ACPB-0226 (Chapter 8)

Canardspeed.com (my build log and more; usually lags behind actual progress)
Flight simulator (X-plane) flight model master: X-Aerodynamics

(GMT+12)

Share this post


Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.


The Canard Zone

×
×
  • Create New...

Important Information