Kent's Long-EZ project

[Barry]

35 minutes ago, jridge said:

Whole thread can be seen on the Canard-Aviators Google.io group....

https://canardzone.groups.io/g/canard-aviators/topic/vendor_report/73376232?p=,,,20,0,0,0::recentpostdate%2Fsticky,,,20,2,0,73376232

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?

[Kent Ashton]

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.

 

 

 

[Kent Ashton]

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.

https://www.johnsonautobodysupply.com/Axalta-Nason-Fulthane-Frost-White-400-53-Gallon.html

 

 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.

[Kent Ashton]

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 Ashton]

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.

 

[Brooks Wolfe]

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. 

[Voidhawk9]

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.

[Kent Ashton]

Just talking to a gent about oil cooling and air flow differential required across the faces of the cooler to get decent cooling.  I have never measured that but this Jabiru reference says 2.4" of water pressure differential is needed for a standard Jabiru oil cooler (which looks like a normal smallish oil cooler).  For comparision, a Lycoming needs around 5-6" of differential through the cylinders.  There is a table somewhere in this thread.   See section 13.4 here about the oil cooler

http://jabiru.no/content/documents/motor/Cooling_Flow_Tips.pdf

It also has a good discussion of engine cooling and air flow.  

[Kent Ashton]

Just reading about Lycoming's Electronic Ignition.   For now, it is fixed timing but promises variable timing for experimentals in the future

https://www.avweb.com/aviation-news/lycoming-introduces-electronic-ignition/

Appears to be a rebadged Surefly EIS (pic 2)   https://www.surefly.aero/     About $1400 for the Surefly.   I doubt the Lycoming version will be any cheaper.   The Surefly site seems to say the variable timing version is available.   Competitive with Lightspeed's Plasma III (dual system with mini-sensor,  $3015)   Probably an easier install than Lightspeed  but the Plasma has a timing readout and adjustment capability.  There is quite a selection of EIs these days.

[Kent Ashton]

Long (11 pages) discussion of the Surefly in the VansAirForce site   http://www.vansairforce.com/community/showthread.php?t=169923

[Royal]

With the amount of technology out there from cars I find it hard that more people haven't been using computers to keep the engines perfect. I know there is a builder using the k20 engines from Honda. 

[Kent Ashton]

A chap asked me:

Quote

I saw in an old post that you were not content with the Long EZ engine mount fixings to the firewall. Did you actually change it?I too am not happy about the existing method, but it has worked well for years. I don't like those metal angle parts being bonded into a composite. I don't like that a round tub is then bolted into the angle with bolts in single shear. The system of 4 pins bolted in such a way will very likely pre-stress the engine mount.   I would be very interested to know how you made your EZ fixing to the firewall, and if you reinforced the firewall for a different method.

I had previously built a Cozy IV.  When I built the EZ, I used the Cozy method of hardpoints in the firewall and multiple UNI strips and BID inside and outside to reinforce the mount area.  I also used the Cozy method for mounting the main gear between bulkheads.   This was a new-build and it is probably not practical to do that on an already-constructed airplane.  Also, it is really not necessary--just a fun thing to try.

From what I read, the only real problem with the original EZ mounts is that the angles weren't sized for heavier engines.  People who have used 1/4" aluminum angle, or two 1/8" angles back-to-back or steel angles don't seem to have problems. I believe two 1/4" bolts through each mount point is adequate.  I do not recall bolts shearing or the 4130 engine mount tubes tearing out where they are bolted.  The problem seemed to be cracks developing in the angles.   I would say to add a few more layers on the inside where the angles are bolted through the longerons, use stouter angles and you will be OK

However, here are some pics of my EZ engine mounts under construction.  It is similar to the Cozy but I for some of the BID layers, I used one or two less layers than in the Cozy plans. It was done mostly by eye and reference to the Cozy plans.   I have a drawing reverse-engineering the changes but it's on another computer.

[Countach74]

Like the look of your extended nose! Did you use the Davenport plans?

[Kent Ashton]

Just reading about this turbo Lance that lost an engine at 15000 feet, then had a fire, then crashed.  http://www.kathrynsreport.com/2020/06/piper-pa-32rt-300t-turbo-lance-ii.html

 I have heard of other tractor airplanes with an engine fire crashing before they could get down and land.  I suppose we have an advantage over tractor airplanes in that a fire is in the aft end of the airplane and behind the fuel tanks but a big disadvantage is that we are so slick, it is very hard to get down quickly from 15,000'.  Also there might be a problem even recognizing that you have a fire in the aft end.  Even if you shut the fuel off, there could still be oil to burn and it'd be hard, I think, to determine if the fire burned itself out.  I do not see any fast way to get down.  Best to look your engine over carefully every chance you get.

[In the old days, pilots used to talk about spinning down through an overcast.  With only needle, ball, and airspeed, it was a stable way to descent without getting into a screaming dive but of course the overcast must be high enough to recover from the spin.  That doesn't help us much.]

[Justin]

Very interesting. Thanks.

[Kent Ashton]

6 minutes ago, Countach74 said:

Like the look of your extended nose! Did you use the Davenport plans?

I started with this drawing (pic 2) I found somewhere.  It was helpful but the problem is that the position of the nose gear pivot is set for a standard short-nose EZ which as you can see in pic 2 is somewhat higher than needed for a long nose.  I did not change the pivot location and adjusted the lower profile to fit.  It looked pretty good when finished.

[Kent Ashton]

A while back I posted a drawing and pic of an annular slot antenna for ADSB UAT 978MHz.  https://www.canardzone.com/forums/topic/18661-kents-long-ez-project/?do=findComment&comment=65684     H/T to Del Schier and Nick Ugolini for the drawings which apparently came from an French chap.

I thought I would post the original drawing with slightly smaller dimensions for Transponder antennas replying on 1090 MHz.    Del noted that the larger ADSB size is "still a very good 50 ohm match at 1050" so perhaps two sizes are unnecessary but I have some extra brass and I think I will make the smaller size and test them in an upcoming transponder check.

[Kent Ashton]

Thinking about starting a thread called "The Best of Facebook" or "Kent's Facebook archive".  I see a lot of good stuff on FB.  I've said many times that FB is terrible for builders.  Good ideas and pics on FB sink into the Marianas Trench never to be seen again.  Also, if any of these gents ever closes his FB account, his posts disappear.  However, it'd be a lot of copying and pasting to do that and I am not sure I'm up for it.  For the time being I will put some here.

Here is nice work on a fuel valve install.  H/T Alex Liedl

[Kent Ashton]

A series on making wheel pant mold.  H/T Les Laidlaw

It appears he used an already-made wheel pants to make a two part mold.  The usual sequence to make the mold--if you have the plug or shape--is to slather the plug with mold release and gel coat.  Then lay up chopped fiberglass mat using fast-setting vinyl ester resin.   Add reinforcements (pic 3) to support and stiffen the mold for later use. Pull the new molds off the plug and use mold release again before laying in the final glass.   I like how he used bumps of something (JB Weld Putty?) to match-up the two halves although I am not sure why that is necessary.  Usually one would lay up the final item separately in the two halves, then join them with tapes when they are out of the mold. 

[Royal]

What do you think takes the longest to do on a full build?

 

[Royal]

Looks like the bumps were used so when he goes to make the two haves he can lay up carbon inside of it and have a really smooth join requiring little to no body work. When we had our rear ducktail spoilers made the guy didn't make them right. had a huge lip that needed bodywork on each one. We found a new manufacturer. 

[Royal]

I started making templates for CNCing them out. I think if people wanted some bulkheads and foam/fiberglass sandwiches to hurry the kit along I might get my own cnc. I have been wanting one anyway.

[Kent Ashton]

38 minutes ago, Royal said:

What do you think takes the longest to do on a full build?

I suppose filling and sanding it the longest task--or at least, it seems that way.  The airplanes can be built pretty quickly if you work on something every day and stay ahead on the parts flow.  I usually say four years is quite doable but a couple of enthusiastic guys can build one in two years.  If you end up waiting for parts, it saps your enthusiasm.   I found most every chapter is fun and it is rewarding seeing the structure come together. 

[Kent Ashton]

13 minutes ago, Royal said:

I started making templates for CNCing them out. I think if people wanted some bulkheads and foam/fiberglass sandwiches to hurry the kit along I might get my own cnc. I have been wanting one anyway.

Hmm, except for instrument panel overlays, I suggest CNC is a waste of time, however CNC wing cores by Eureka were worth the price but I think Eureka no long sells them.  I can trace out a bulkhead and have it glassed on one side in an afternoon.  And + or - 1/8" inch is as accurate as you need to be for things like bulkheads and fuselage sides.  Burt made it simple to build so CNC is just interposing unnecessary operations.  Nevertheless, it's the journey so if it makes you happy, fine.  🙂

 

[Royal]

Well I have done so many restorations building parts from scratch and sanding 20ft straight is getting old. I wanna build an airplane but man. I started making fiberglass widebody kits that actually fit unlike some junk ebay is selling. Making an 8x4 sheet sandwich could probably be made in a day I think. It would be nice to get a build down to 1-2 years. Say you had the outside skins with the spar made in  5 sections, nose cone in 2, body in 2, canards in 2 and the alerions and small parts can be left for them to build. 

I did notice while putting them in CAD and mirroring the other side that it wasn't perfectly symmetrical. Is that something you have found on the open-ez?