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Kent's Long-EZ project


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  • 2 months later...

Saw this oil cooler door idea (pic 1) on a FB page but I don't like it.  The chap has an ingenious linkage to open and close the slots in flight but the problem is that when full open, half the cooler is blocked by the apparatus and even when open, the slots create drag on the air flow.  In hot weather, you will want the whole cooler working.

I have a pic of a cooler using louvers by Marc Z. that is a better idea but it might be copyrighted so you will have to imagine it.  :-)

I did not give this enough thought when building the Cozy.  Eventually I arrived at this slider (pics 2,3) which is satisfactory but  not in-flight adjustable.    With experience, I know about where to set it.  This time of year (Nov), it covers about 2/3rds of the cooler.   In the winter it will block the entire cooler.   Doing it again, I would offset the cooler which might have given the space for a cable-operated slider.

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

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Yikes!  $454 for a single CHT bayonet probe!  (pic)  And _without_ bluetooth or Wifi.   I posted a pic and description previously how to make a homemade probe for less than $10 here.  

https://www.canardzone.com/forums/topic/18661-kents-long-ez-project/?do=findComment&comment=63649

Even my puny mind can figure them out: twist the two wires together, make them contact the hot metal.

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

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1 hour ago, Kent Ashton said:

I have a pic of a cooler using louvers by Marc Z. that is a better idea but it might be copyrighted so you will have to imagine it. 🙂

LOL.  Since our activities fall under Fair Use copyright law, and I'm sure you'd give credit where credit is due, I say share away!  

Good to see you Kent!  The world is now in harmonic balance once again.

:banana:

Jon Matcho :busy:
Builder & Canard Zone Admin
Now:  Rebuilding Quickie Tri-Q200 N479E
Next:  Resume building a Cozy Mark IV

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"Yikes!  $454 for a single CHT bayonet probe! "

Wow. Talk about excessive. I suppose $150 would be fair since it is nicely made and replaces other parts, and is certified. I wonder how much of the $300 excess is the certification process?

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4 hours ago, Kent Ashton said:

I have a pic of a cooler using louvers by Marc Z. that is a better idea but it might be copyrighted so you will have to imagine it. 🙂

Hah. Here's what I have - no imagination necessary. 99% uncovered when open, 90% sealed when closed. I rarely use it, since I don't live in a cold place. But since it exhausts down below the strake, I do get a pitch trim change when I shut off the airflow to the cooler. THAT was strange.

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Here is an irritating little problem with the Cozy.  It is mentioned in the Cozy FAQs but easily missed.   The problem is that you can build your landing brake flush with the belly but over time, the pull of the retract springs can make the forward edges lift up.  The best solution is to make the hinge as wide as possible.  Alternatively, it may not happen with an electric landing brake that can be stopped before exerting a pull on the landing brake.  Doing it again, I would lengthen the hinge AND use the electric brake actuator.  The plans brake lever is tre fiddly.

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

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7 hours ago, Kent Ashton said:

The problem is that you can build your landing brake flush with the belly but over time, the pull of the retract springs can make the forward edges lift up.

Not just the pull of the springs, but warping of the glass. I fixed mine when it warped by cutting slices in the top surface glass, supporting the left and right edges and weighting the middle so that the LB would take a slight curve - higher at the sides. Then I glassed 2 BID over the slices to lock in the shape. That was about 9 years ago, I think, and it's kept shape perfectly since - when it's pulled up, the sides hit about 1/8" early and then the center pulls up, keeping the whole thing flat.

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9 hours ago, Marc Zeitlin said:

I fixed mine when it warped by cutting slices in the top surface glass, supporting the left and right edges and weighting the middle so that the LB would take a slight curve - higher at the sides. Then I glassed 2 BID over the slices to lock in the shape.

Good idea and  I suspect rewarping could be prevented by building in hard points near the retract arm so the pull is transferred to the outside edges.   I thought about trying to heat it in an oven but every google source I found says fiberglass won't straighten.  Must try that on a test piece first.

Barry, the distortion is pretty strong.  I doubt a magnet would do it but nice try.  :-)

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

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On 11/6/2019 at 12:27 PM, Marc Zeitlin said:

Hah. Here's what I have - no imagination necessary. 99% uncovered when open, 90% sealed when closed. I rarely use it, since I don't live in a cold place. But since it exhausts down below the strake, I do get a pitch trim change when I shut off the airflow to the cooler. THAT was strange.

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Marc,

What type of tubing do you have? It looks like a hard wall of some kind, almost like copper.

Thanks

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9 hours ago, Barry said:

What type of tubing do you have? It looks like a hard wall of some kind, almost like copper.

What "tubing" are you talking about? The hoses from the oil cooler? The aileron pushrods? I don't know to what you're referring.

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12 hours ago, Barry said:

Sorry, the oil cooler hose/tubing. It doesn't look like the typical stuff I'm used to seeing.

That's AN-8 Aeroquip 466 (or the equivalent) hose with integral silicone firesleeve.

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  • 2 weeks later...

Just reading this 2017 Varieze accident.  Water and debris in the fuel.  Engine found to be corroded by the NTSB.   http://www.kathrynsreport.com/2019/11/fuel-contamination-rutan-varieze-n830s_19.html    The 35 year-old, 691 hour airplane only "flew" 2.1 hours from 2015-2017.  It was inspected 4/2017 and registered to the non-builder pilot in 6/2017.    Pilot said he had flown a dozen trips in it before the 9/2017 accident.  Take a look at the water and gunk in his fuel in the pic below (annotations mine) or here  https://dms.ntsb.gov/pubdms/search/document.cfm?docID=477708&docketID=62975&mkey=96064

Here is my suggested scenario: An older Varieze becomes inactive, sit outdoors with mogas in the tanks for some years and also got rain and dew in the tanks past 35 year-old o-rings.  Non-builder seller gets a light condition inspection from a shop not used to dealing with Varis and sells it to new owner.  New owner takes the inspection at face value.  After a few trips the gunked-up fuel finally catches up with him.  

I don't think I have ever seen more than two drops of water in my tanks or gascolator but my airplane is hangared.   Frankly I get a little careless about sumping the tanks for every flight but I do faithfully check the gascolator screen and Earls inline filter for debris every year.  Rare to find anything.    I suppose this much water and dew could leak past 35 year old fuel cap o-rings.  The report does not discuss mogas that I could find.  That gunk in the tanks--that was there for a while.  

 

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

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Discussing misfiring with my friend with a new-to-him Cozy said "I thought the left mag was on the left side of a pusher".   Well I suppose it could be but it is dangerous to get this confused.  The "left mag" on a tractor airplane is usually the impulse mag on the left side of a tractor airplane but it is on the right (starboard) side of a pusher.  This is important because starting on the non-impulse mag or in "both" can result in a kickback that breaks the starter.  

Also, the mags must be wired correctly to the ignition switch so that when you intend to disable the "right" mag (on the left side of a pusher) in order to start the engine, you are disabling the non-impulse mag. 

Also #2, as even newbies know, mags are hot unless they are grounded-out.  Turning a magneto ignition switch "On" is actually opening the ground wire to that mag and un-grounding it.  Incorrect wiring might mean you are making the wrong mag hot.  This has occurred with incorrectly wired or defective key ignition switches.  IMO, it is better to use toggle switches for mags, then use a key switch for starting.    A broken "P-lead" wire also makes the mag hot so be careful with those, too.

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

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6 hours ago, Kent Ashton said:

Just reading this 2017 Varieze accident.  Water and debris in the fuel.

Thanks for pointing that out. I guess the final report finally came out after more than two years!

I talked to pilot shortly after the accident. He was based near me. Luckily, he recovered from his injuries.

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  • 4 weeks later...

A chap was asking if he should put small NACA scoops on his wheel pants to cool the brakes.

I would think that heat in the rotors, and pads from a heavy-weight, hard-braking landing is generated in seconds and blowing air over the brakes at taxi-speeds would seem to take minutes to lower their temperature.   As an amateur welder, I don't find that blowing on a hot piece of steel has much effect;  it generally cools by radiation or a dip in water.  By the time air-cooling would work, the pads have absorbed the heat and faded or the heat has been conducted into the caliper and into old moisture-laden brake fluid which can boil and you've lost your brakes.  Also there would not be much flow into a forward-facing NACA scoop during a taxi-back downwind after landing so my guess is that they are likely a waste.

OTOH, the drag generated by NACA scoops is present all the time.  Think of it this way:  In flight, air is taken into the wheel pant, accelerated to almost the speed of the airplane inside the wheel pant, then returned to freestream, turbulent.  That takes energy in the form of drag.

I saw a Long-EZ at Sun-n-fun one year with the wing propped up on a 2X4.  Pilot had landed (hot?) with his wife, baggage pods and fuel.  Heat radiated off the brake rotor had softened the strut which had folded.  He was trying to straighten it out while it was still hot.  That has happened a lot.

A buddy of mine was taxi-testing his newly-bought airplane--an airplane that had sat for some years with old brake fluid.  After a few runs down the runway and taxiing, his brakes faded on one run and he ran off the end of the runway.  Keep your brake fluid fresh.

Which reminds me from my F-4 days that the fire department carried spike strips on their trucks.  If a fighter landed so hot its brakes were glowing, the firemen might have the pilot taxi the airplane over the spike strip to deflate the tires, otherwise the heat conducted into the tire (which was already cold-inflated to some huge psi) could make the tires explode.

Experience with the canard airplanes has shown that plans-recommended brakes are fairly marginal.  

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

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Chaps, I have miles of this 16 and 18 gauge wire I got from a surplus dealer.  I will sell 100 foot length of each for 20 cents a foot and ship it in a flat-rate box for $8.  This is less than 1/2 the price of Spruce.  Total price $48.00.  PM me if you want any.     kjashtonATvnetDOTnet

If you want to know what it is and if it is suitable for aircraft (it is) see my earlier post about wire.   https://www.canardzone.com/forums/topic/18661-kents-long-ez-project/?do=findComment&comment=61303

 

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

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