Kent's Long-EZ project

[Kent Ashton]

Geez, after buying a $200 Vividia borescope to look at my valves (see Aug 24 in this thread), I was just reading about this one (pic) for $29.  The previous problem with these cheapies was that they were not flexible enough to stick them in the plug hole and bend them back to look at valves.  A Vans owner says this one can do it.  It could probably be glued to a piece of bendable wire and inserted into the cylinder.  

Why do this?  Regular Lycomings have notoriously-poor valve stem lubrication.     https://web.archive.org/web/20050217090118/http://www.prime-mover.org:80/engines/Marvel/tbo3.html   So the valve stems wear and the rocker arm pushes the valve head off center.  Heat does not transfer evenly around the valve head to the valve seat, the valve head gets heat-stressed and a piece breaks off, or the head breaks off.  What you don't want to see is a half-moon discoloration (pic).  There is a really bad case in this video  https://youtu.be/x6OyfoV1Z2I

 

Edited September 16, 2018 by Kent Ashton

[Voidhawk9]

That is a very sad looking head.

[Kent Ashton]

Some words on filling:  I have painted three canards and several cars and bikes and made about all the mistakes you can make so perhaps I've learned some things.  My buddy who is repairing and painting his Cozy came up with this problem (pic).  He says "I have sanded the primer to #2000 grit and I see pinholes [again].  What to do?"

He has two problems:  He did not kill the pinholes before priming and he is sanding the surface too smooth for further paint to get a bite.  For me, there is a logical order to painting a canard, that if followed will result in fewer mistakes.  Here is mine:

1.  First, do your filling and sanding to get the surface perfect, and sanded down to about a 320 grit.  Along the way, use a stiff aluminum bar marked up with a big Sharpie.  Rub the bar perpendicular to the chord.  The bar will leave oxide and Sharpie smudges on the high spots.  Sand them down a little and repeat until the smudges are everywhere evenly.  On curved surfaces like the nose, I use stiff, flexible things like welding electrodes or old bandsaw blades held over the surface to find high and low areas.  View the surfaces from many angles with lights at different angles.  The mistake here is usually thinking you are ready for the next step but you are not.  Primer/surfacers will not fill pits and deep sanding scratches.  Undetected defects are usually present.  We have to fix those here before priming.  To find them, I spray the whole surface will a thin mist of black sandable rattle-can primer and sand it all off.  That will usually show many undetected defects.  Fix all of them except pinholes.  Sometimes a new layer of filler over the whole surface is the easiest path.  Sand to about 320 grit.  Repeat as necessary.  It is a mistake to sand smoother than 320 grit.  Now your surface is truly flat and smooth but there will be pinholes.

2.  Fill the pinholes with the "Cory Bird epoxy wipes method"--three to five wipes with straight epoxy allowing it to tack up between wipes.*  The wipes will fill the pinholes but they will leave hard ridges and runs that will need sanding flat.  IMO, the reason you don't want to sand finer than 320 grit prior to the wipes is that straight epoxy wants to clump-up due to surface tension and a very slick surface will help it clump.  Also, it's hard to leave any epoxy when wiping a very slick surface so you can't build up any thickness.  My objective with the wipes is to get enough thickness of straight epoxy that I can wet sand it flat without going through it.  Sanding through the hard wipes may expose more pinholes.  Sand the hard wipes down to 320-400 grit.  Now my surface is smooth, has a thin layer of epoxy and pinholes are filled.

3.  Epoxy is a pretty good primer for a topcoat if it has the correct bite but I usually spray a sandable primer/surfacer and wet sand that to about 400 grit.  Now I'm ready for a topcoat.

*NOTE:  Cory, who built a championship airplane, said a 36 grit finish was just fine in preparation for the epoxy wipes    http://www.ez.org/t/cp77-p4   He used the wipes to fill big sanding scratches.  I find it better to work those out to a finer surface.  Cory suggests a 3-4' sanding spline.  I usually get good results with an 18-20" board but I have not won any Oshkosh awards.  ?

[macleodm3]

Thanks for the tips Kent!  What are you representing in your photo... the way it should be done or the way it shouldn't be done?  I see two scratches, some uneven micro around the NACA, and an uneven gap.  It still looks fast... if mine looks that good I am going flying.

Edited September 26, 2018 by macleodm3

[Kent Ashton]

1 hour ago, macleodm3 said:

Thanks for the tips Kent!  What are you representing in your photo

My friend was showing me his pinholes but now that you mention it, maybe they are not pinholes.  Below is what I usually see as pinholes (pic).  They are larger and paint does not want to bridge them.  My friend's look tiny; I don't think I've seen that.  Maybe my friend just has some texture problem with the primer and just needs to sand more.  I dunno.

 

Edited September 26, 2018 by Kent Ashton

[Kent Ashton]

To close the loop on this, my friend said he sprayed a thin coat of primer on his "pinholes" and sanded to 500 grit and doesn't see them anymore, so maybe it was just the texture of his primer and 2000 grit sanding giving that effect.  Normally you can spray gallons of  paint over a pinhole and it will just laugh at you.

However, with sandable primer I have occasionally swiped the wet primer with an old credit card when a swarm of pinholes appeared.  It filled them and the primer could be sanded flat but it  was more work.  Best to kill them before priming.

[macleodm3]

Yeah... I see pinhole swarms in my micro too.  I am not worried about them... I'll fill them with raw epoxy like you mentioned.  How big of a pinhole can you fill with the raw epoxy?  Most of mine are small (1/16") but a few are larger perhaps 1/8" or 3/16" diameter.

[Kent Ashton]

50 minutes ago, macleodm3 said:

Yeah... I see pinhole swarms in my micro too.  I am not worried about them... I'll fill them with raw epoxy like you mentioned.  How big of a pinhole can you fill with the raw epoxy?  Most of mine are small (1/16") but a few are larger perhaps 1/8" or 3/16" diameter.

I don't have any exact numbers.  Three wipes for me will fill or almost fill a 1/8" pit.  If they are large pits they don't exhibit the same surface-tension pull-away as pinholes--they are just holes to be filled.  Sometimes I  go around putting dots of wet micro on them that I sand down later.  Or I might put a dot of wet primer-surfacer on them when they show up during priming (argh!) and sand them down later.

Here are some pics you might find interesting  Pics 1,2: after several wipes.  The result is not as flat as you might think although I squeegeed pretty thoroughly.  I believe it's due to surface tension causing the epoxy to clump or maybe I just needed more squeegee.  Pics 3,4: I marked off low places and pits after the first application of micro and sanding.  I would probably not try to patch those and just lay down a new layer of filler but the red marks will be helpful because they will show through when sanding and tell me I am filling the low spot and not leaving the filler too thick.  Patch-filling is problematic because the batch hardness changes and it's hard to get a patch flattened to match the surface around it without sanding the surrounding area low. Pic 5: I find it useful to pre-fill low places and high places before doing the whole wingl.  It is hard to fill a low spot like a spar-cap trough while trying to get an even layer of filler over the entire wing.  Same for high spots.  Best to pre-fill them, sand them flat, then do the whole wing.

[Kent Ashton]

I was wondering why Google's "+" search feature wasn't working.  It was very useful to put "+" in front of search words and Google would reliably search for all the words.  That went away when Google wanted to use the + character for Google+.  However, I found out recently that Google's Advanced Search feature will do that but there's a trick to get there.  

For example, I wanted to find images of throttle cables:  Do a Google Image search for anything.  When the search results come up, select "Settings" at the top of the page and go to "Advanced Search".  Change or put your terms in "all these words" and you'll get a lot more pertinent results than a generic search.    LIke this:

https://www.google.com/search?as_st=y&tbm=isch&hl=en&as_q=longez+throttle+cable&as_epq=&as_oq=&as_eq=&imgsz=&imgar=&imgc=&imgcolor=&imgtype=&cr=&as_sitesearch=&safe=images&as_filetype=&as_rights=

Google+ has gone away but I don't think the + character has been restored yet.

[Kent Ashton]

I talked about my homemade smoker back on page 5 which was not very successful.  Since then I've upgraded to an Akorn Char-griller https://www.chargriller.com/collections/kamado-grills  a cheap version of a Big Green Egg kamado cooker.  The Chargriller is steel--about $290 from Walmart, Lowes, etc versus $750-$1000 for the true ceramic smokers.  It's one of the best things I every bought!   I just mound up some charcoal briquets and apple wood, give it about 20 minutes to come up to temperature and it will cook for 3-5 hours+ with very little tending.  Yesterday I added a Pitmaster IQ110 found on Craiglist.    https://pitmasteriq.com   It is a little temp-controlled fan that keeps the cook temperature perfect.   Mostly I cook St Louis ribs (3 hrs) or brisket or  the occasional chicken or spatchcocked turkey.  They have all come out great.  Must try a pizza sometime.

There are plenty of Youtubes of folks cooking delicious these on these kamado grills.  Check them out.

[mquinn6]

Kent, do you think it would be good for curing smaller layups?  ?    

When my parents got into smoking / slowcooking - they went way overboard...  but the flavor was good (be careful of wood selection - it makes a HUGE difference in flavor!).

M.

[Kent Ashton]

Saw this question below on a FB page.  None of the answers suggest comparing the pressure differential above and blow the cylinders with a relatively simple water manometer setup.    https://www.canardzone.com/forums/topic/18661-kents-long-ez-project/?do=findComment&comment=61602   I would guess his cowl exhaust area is too small.  It is certainly smaller than you see on most airplanes.  He has a big opening around the prop but there looks to be a flywheel blocking that path.  I don't recall the rule-of-thumb exactly but I think it says the exit area should be two or three times the inlet area.  Also the top of the cowl looks tight to the tops of the cylinders.  Those restrictions might be creating backpressure that restricts flow.  In my experience above, I moved the cowl exhaust opening to a better place  but did not change the intake size.  That improved cooling considerably--it just allowed the air to get out.

 

[Kent Ashton]

Further on the airplane above:  I'm a little surprised that his oil cooling is OK since the flow has to make a 80 deg turn against the baffle and get compressed to go out the slot which looks to be only 1/3rd the area of the cooler.  He seems to have a dedicated intake duct for the cooler.  These things are interesting to speculate on.  If he made the cooler exit more efficient, it would likely make the cowl bigger but maybe the drag from a larger cowl would be offset by less cooling air being used for the cooler.

[Kent Ashton]

TAKEOFF-TURNBACK -  Ever since I finished the Cozy I have thought I should test how much speed and altitude it would take to turnback to the runway.   I never really liked the idea of chopping the power right after takeoff to test that but my engine has always been pretty reliable and the traffic was light one day so I tried it a couple times.  This is a 270-90 degree turn.

Conditions were: light weight (me and 20 gallons),  Cool day (65F), light winds, 105-110 climbout speed, chop to idle power, Instantaneous reaction, about 45 degree bank.

From 300' AGL it was just doable flying on the edge of nose-bob.  From 400' AGL I was able to fly a bit faster, had no nose-bob, and landed a bit fast. I did not try it from 500 feet but I imagine that would be a very comfortable altitude with those conditions.  You would have to consider the suddenness of the engine failure, your reaction time, the winds, temperatue, gross weight, and speed so I probably would not like to do it for real at less than 500' AGL.

You might try it first at altitude of say, 1000'-3000'.  Establish a climb configuration, at a given altitude chop the power and make a 270 turn followed by a 90 in the opposite direction.  Note the altitude it takes.   I will try that next time I'm up.  I have flown with fellows who do not like to fly into nose-bob, or fly into nose-bob at 45-50 degrees of bank but IMO, that's what it takes for an optimum turn.

I am not in the habit of preplanning a turnback before an actual takeoff but it's worth thinking about.  20 knots of wind will move the airplane 1012 feet downwind in a 30 second turn.  In the summer at heavy weight I am sure it would take much more altitude.  It would take some before-takoff planning, then an instant decision based on proficiency and a gut feel that "this will work".  I doubt we can develop either of those without some practice at altitude and having a go/no-go altitude in mind for actual takeoffs.

The guys on the ramp got a thrill.  They said "we thought you'd lost your engine".  🙂

Edited January 1, 2019 by Kent Ashton

[Marc Zeitlin]

5 hours ago, Kent Ashton said:

Conditions were: light weight (me and 20 gallons),  Cool day (65F), light winds, 105-110 climbout speed, chop to idle power, Instantaneous reaction, about 45 degree bank.

From 300' AGL it was just doable flying on the edge of nose-bob.  From 400' AGL I was able to fly a bit faster, had no nose-bob, and landed a bit fast. I did not try it from 500 feet but I imagine that would be a very comfortable altitude with those conditions.  You would have to consider the suddenness of the engine failure, your reaction time, the winds, temperatue, gross weight, and speed so I probably would not like to do it for real at less than 500' AGL.

I've practiced this in my plane as well. We did a Vx climbout until at 100 ft., then Vy climbout. At 400 ft. AGL, we chopped the throttle, and then waited 4 seconds (to simulate the "WTF JUST HAPPENED" reaction time of the average human being before the training kicks in). At that point, I started a turnback, set the airspeed to BEST GLIDE (NOT just above stall - BG is about 80 KIAS, with a 62 KIAS stall speed), and as Kent says, about a 45 degree bank (which IS optimal). It's certainly exciting - making 45 degree turns when 200 ft. AGL and offset a few hundred feet from the runway is not usual, to say the least. But in a COZY MKIV, it works. I think Kent could do it at 300 ft AGL because he didn't wait 4 seconds - if you do wait, I don't think you're making it back. I would tend to agree that 500 ft. AGL might be the lowest I'd try it in a real surprise situation, but it would also depend on what's around, CG, GW, etc.

I was very surprised, the first time I tried this, at how close to not making it we weren't - it really wasn't a squeaker - we probably touched down a few hundred ft. from the threshold. We tried a few different bank angles and a few different speeds. The best performance was always at best glide (L/D) speed, and with about a 45 degree bank.

[Voidhawk9]

On 1/2/2019 at 8:37 AM, Marc Zeitlin said:

It's certainly exciting - making 45 degree turns when 200 ft. AGL

The best performance was always at best glide (L/D) speed, and with about a 45 degree bank.

2

Steep turns at below 500' (and typically at 200' AGL) are part of PPL training here in New Zealand. Good fun and a bit exciting, for sure. But not specifically related to 'the impossible turn', but rather poor weather / precautionary landing simulation.

 

Finding that best performance is at best L/D speed (for straight and level, I presume) is interesting. My mind wonders if a little extra speed might help given the loading being applied, but then minimum radius is a consideration too, so that may balance things out. Just off the top of my head!

 

I haven't any experience in canards yet, but I have done a little testing of this in a couple of other types. A DA-20 can do it with ease from 300'. We always joked that you could glide to your home runway in one of these from ANY location, including x-country flight! 😜 An R200 doesn't seem to be capable of returning to the runway until established downwind, and then only if there is little or no crosswind against you!

 

[Kent Ashton]

On 1/1/2019 at 2:37 PM, Marc Zeitlin said:

I've practiced this in my plane as well. We did a Vx climbout until at 100 ft., then Vy climbout. At 400 ft. AGL, we chopped the throttle, and then waited 4 seconds (to simulate the "WTF JUST HAPPENED" reaction time of the average human being before the training kicks in). At that point, I started a turnback, set the airspeed to BEST GLIDE (NOT just above stall - BG is about 80 KIAS, with a 62 KIAS stall speed), and as Kent says, about a 45 degree bank (which IS optimal). It's certainly exciting - making 45 degree turns when 200 ft. AGL and offset a few hundred feet from the runway is not usual, to say the least.

It seems to me that Best Glide is not the speed to fly here.  I would say it's the Minimum Sink speed, typically a lower speed, i.e., just on the edge of nose bob.  We are not trying to glide any distance, we're trying to turn around with the least loss of altitude while maintaining position over a point on the ground.  Play with this calculator  http://www.csgnetwork.com/aircraftturninfocalc.html  

65 Kts/45 deg bank/360 turn takes 21.5 sec with a radius of 376'

80 kts/45/360 takes 26.5 sec with a radius of 570'

At the higher speed you are sinking faster, taking more time to make the turn, and flying a longer flightpath.  N'est pas?

Edited January 4, 2019 by Kent Ashton

[Marc Zeitlin]

On 1/4/2019 at 6:17 AM, Kent Ashton said:

It seems to me that Best Glide is not the speed to fly here.  I would say it's the Minimum Sink speed, typically a lower speed, i.e., just on the edge of nose bob.  We are not trying to glide any distance, we're trying to turn around with the least loss of altitude while maintaining position over a point on the ground.  Play with this calculator  http://www.csgnetwork.com/aircraftturninfocalc.html  

65 Kts/45 deg bank/360 turn takes 21.5 sec with a radius of 376'

80 kts/45/360 takes 26.5 sec with a radius of 570'

At the higher speed you are sinking faster, taking more time to make the turn, and flying a longer flightpath.  N'est pas?

A few references:

https://www.aopa.org/news-and-media/all-news/2011/may/19/impossible-turn-practice-makes-possible

indicates (without any supporting evidence) BG speed and a 45 degree bank. They don't say whether that's BG in a turn or S&L, but since 1G BG is all anyone ever reports, that's what I'll assume they mean. In my plane at the GW's I was at, BG is somewhere in the 80 - 85 KIAS region.

This:

http://pilatusowners.org/wp-content/uploads/2014/01/US-Navy-turnback-study-1982.pdf

is an empirical study that tested success with your parameters - just above stall speed, with different bank angles - 30 degrees and 45 degrees seemed to work the best in these test cases.

This:

http://peter-ftp.co.uk/aviation/misc-euroga/2013-turnback.pdf

is a theoretical analysis, but is backed up with empirical results from testing, and recommends a speed of 5% above the stall speed IN THE TURN.

So we may be saying similar things here, due to the differences between stall speeds in the 45 degree bank turns and at 1G (a factor of about 1.2). My airplane stalls, in the configurations I was testing, at about 62 KIAS. So with a 45 degree bank, the stall speed would be 74.5 KIAS. Now add on the 5% margin recommended in the last reference, and we're at 78 KIAS - almost exactly the 80 KIAS I noted was the best case for us. There's no way MY plane could do a 65 KIAS indicated turn at 45 degrees of bank - I'd be below my indicated stall speed and there's obviously be no margin on top of the stall speed. If we assume that (as is always the case) between min sink speed and stall, the descent rate increases, then it's better to be somewhat above stall, which the 80 KIAS gives me, per the last reference's recommendations.

I think that the canard capability to get right up to stall speed makes this maneuver a lot safer than in a conventional plane, where a 45 degree bank at 5% over stall speed is pretty much begging for a stall/spin accident.

[Kent Ashton]

This video is interesting.  The engine failure appears to occur at no more than 250' AGL.  There is plenty of open water to ditch in.  It appears he wanted to make it to the open field and at 20-25 seconds he appears to have a flight path vector well out onto the open field but fails to maintain it.  He seems to have adequate speed (no horn heard) but only at the last second figures out he's going to hit the berm.

https://www.youtube.com/watch?v=94IURXCoY5A

----------------------------

Nose wheel futzing:  My nose wheel bearings would get loose.  First, I made aluminum bushings for the bearings that met in the middle of the rim.  They were sized to take all the slack out of the bearings.  That worked for a while but the bushings ride on a narrow circumference of rubber on the outside of the bearing which seems to wear; the bushings themselves probably wears a little, too.  The bearings got loose again after a while.  This time I took a bit off the inside and outside of the bushings and used wide washers to bear on the rubber seal, leaving about a 1/8" gap between the bushings.  This will allow me to take out the play by tightening the axle bolt and nut.  Make the device the same width as the NG forks.  I tried to load a pic but for some reason, I am limited to 122Kb

[Kent Ashton]

Canard interest is spread-out on the net like bird-watchers wandering in a huge forest.  They want to get together and share their bird-finds but they can't find each other.  A couple of them are together over here, a couple over there.  It's pitiful.   If they would coalesce in one place, they'd get more enjoyment out of [owning canard airplanes] and sharing their experiences.  For example, there is this site, CanardAviators.com, EZ.org, CanardCommunity.com, Socal EZ Group Squadron III (Facebook),  Rutan Longez and Varieze (Facebook), Cozy Aircraft-Canard Avaition [sic] (Facebook), Cozy MarkIV (Facebook), Cozy Mk IV Pilots and Builders (Facebook), the Cozybuilders google group, the Canard-aviators yahoo group, Terry Schubert's Central States Association.  Recently there is David Orr's Squadron III newsletter and lonely personal blogs like Longez Neightfourdr (Facebook) and Varieze nfoursixez (Facebook).  I also know of a couple dozen personal builder websites.  Some are active, some are dead or nearly so.  They do not share.  Newbie's ask the same old questions and reinvent the wheel.

Like some of you, I refuse to join Zuckerberg's corrupt organization   Other sites and lists are interesting and serve a good purpose but the effect is to spread the community out thinly.  We do not have a Rutan or Puffer sponsor we can coalesce around.  Persons interested in canards have to find builders and flyers where they can.  For that reason I choose only to post on this web-based site and urge you who may come across my thread to ditch your Facebook memberships and post here.  Your pics and comments will not dribble down to the bottom of an ad-filled FB page and be lost in obscurity.  With the "search" function, you can actually find information.

Over 23,000 people have looked at this thread and over 47,000 have looked at my Sales I've Seen thread so there are folks out there who will read your posts if you make the effort, talk about your experiences, and post a few pics.   Thanks to Jon for hosting this site.

Edited January 18, 2019 by Kent Ashton

[mquinn6]

You might have answered your own question...  As "everyone" respected Burt and Puffer - all these others wish to have that same "revere".  But nobody has come out a clear winner (they all have their merits - but the community has not aligned with any one).  In our encouraged polarized world we live in - I think the midset is that it improves things...  Ok - I have no idea - so I am going back to reading the CP and CSA and waiting for the registration challenges to get worked out on my bird before I go further...

 

 

 

[Kent Ashton]

A funny, sad story:  I had a friend nearby who finished a Long-ez.  He had not flown for years and took perhaps 15-20 hours to pass his biennial with a CFI in a spam can.  After that we flew in the Cozy for 4-5 hours.  He was not very proficient.  He had learned the old Cessna habit pattern: "pitch controls speed, power controls altitude".  That works very well in a Cessna but less well in a canard.  On base and final, power WILL control glidepath or altitude over the long run but a slick airplane like a canard will often just get fast if you don't make a pitch change with the power.  We talked about how his Cessna habit was not helping.  He needed to control base glidepath with the stick, ie., maintain a constant glidepath and use power to control speed.  He understood it intellectually but couldn't apply it in the airplane.

When he started flying his EZ, observers saw him landing like an X-15: screaming.  He could barely get stopped.  After a few flights some pine trees grabbed his airplane as he was rolling out final; he was lucky he didn't get killed.  When asked what happened, he said "The airplane got low on base.  I kept adding power but it would not regain the glidepath."

Edited January 21, 2019 by Kent Ashton

[Voidhawk9]

You can lead a horse to water, but you cannot force him to drink.

[Kent Ashton]

imagine what results would come with our little airplanes if high-strength aero analysis was applied to them.  Look at the tiny aero changes on the Mercedes and Ferrari F-1 cars at 2+00 and 3+00 and later in the video. The front wing has 5 or more leaves and all sorts of vertical devices to affect the airflow.   The video is rather long, listen at 1.5X speed.  It makes me feel like a cave man trying to figure out airflow through the engine:  "Igor think air go this way; make dam to go that way.  Igor happy."

https://youtu.be/2Gn7_s8s2sw

 

Edited January 22, 2019 by Kent Ashton

[Voidhawk9]

I recently read the book "How to build a Car", which is an autobiography of the most successful F1 car designer in history. Mostly it is the story of the cars he designed and built, and it is a great read that I highly recommend.  From the book it is clear that the aerodynamics are very clever indeed, but also that they are strongly focussed on ground effect and working around very defined and strict limitations imposed by the FIA.

So what you see on F1 cars, Indy cars, etc. may or may not apply well to our unrestricted flying machines.

Edited January 23, 2019 by Voidhawk9