Kent's Long-EZ project

[TMann]

What are the advantages / disadvantages of using thick or thin laminates?

During construction of the blank, it makes it possible to change the direction of the grain of the wood which results in improved strength.

[Kent Ashton]

Ya know, the folks who really have good experience building props do not let many of their secrets out.   As a rank amateur I'm happy to talk about it.

 

For example, the prop carver I made is perhaps a little taller than it needs to be so as the stylus follows the prop template, the router cuts in an arc.  Not a huge problem--the stylus can be adjusted to compensate but it's not the straight vertical cut one might imagine.  The cut is going to be an arc in any case but keeping the pivot point as close to the prop as possible would minimize it.

 

I got impatient and used an ordinary straight router bit but would've gotten nicer cuts with a coarse Saburr bit (pic).  The router bit wants to dig in.  I doubt the Saburr bit would do that.

 

As a first effort, I tried to cut the blades about 3/16" fat by setting the router bit higher than the stylus.  If I had more confidence in the thing, I would try 1/16" fat but my blades are thin and I didn't want to dig into them.  Of course, setting the router bit high does not help when cutting the side of something, like the leading edge.  That's what dry micro is for.  :-(

 

For removing wood after most of the sawing and chopping is done, I had a 3"diameter version of this carbide wheel in the angle grinder.  Worked pretty well but don't get sloppy 'cause it will really take off the wood.  Then a coarse sanding disk, then the hand rasp.

 

Lastly, the second iteration of blade-fitting templates.  Printed on the laser printer, glued to Formica sheet.  The 1" offset lines can be used to check the blade angle vertically and horizontally.  One prop-builder said to work the flat side to shape and to the proper angle, then gradually work down the cambered side until the templates almost touch.  Spray paint and go fly!  :-)

Edited May 12, 2017 by Kent Ashton

[Jon Matcho]

Ya know, the folks who really have good experience building props do not let many of their secrets out.

Attached are pictures of a small cross-section of my damaged MT propeller starting 10" out from center. What strikes me is the dark and light woods (being two different materials) AND both are tapered in size in opposite directions.

[Kent Ashton]

Interesting, Jon.  The dark part looks like fiberglass laminate but why/how does it get thinner?  Are you showing two ends of the same section?  And why do they embed dimes?  No wonder those props are expensive!  :-)

 

Here is some more noodling in my prop:  took a photo, imported it into CAD, scaled it a bit, drew some lines to get the hub transition consistent on both sides.

 

[Jon Matcho]

The dark part looks like fiberglass laminate...

I suppose it could be, but the outside shows ~3 plies of glass which are thinner and of a different color. Conclusion: The dark area is fine plywood. There are around 12 plys near the root tapering to 3-5 outboard.

 

...but why/how does it get thinner?

I can figure the how, but not the why.

 

Are you showing two ends of the same section?

Yes, the same section ends shown in the first pic.

 

And why do they embed dimes?  No wonder those props are expensive!  :-)

To balance the prop. I assume you're kidding, I just wanted to show proportion.   

 

Here is some more noodling in my prop:  took a photo, imported it into CAD, scaled it a bit, drew some lines to get the hub transition consistent on both sides.

Very nice!

[Kent Ashton]

Speaking of LEDs, here is an idea for LED post lights.  I couldn't bring myself to spend $37 to $65 for a single post light.  They are a bit fiddly to make but they are "adjustable".  Stick them in holes in the instrument panel; twist and bend the soft aluminum to shine them where needed.  :-)   Dim them in sets with one of those cheap ebay PWM dimmers.

 

Not much need for them with a glass panel, of course, but they were fun to make.

 

[Kent Ashton]

Prop progress:  Not perfect and will take a bit of spot filling before doing the glass but I think it will be OK.  It requires less than 50-cent piece on one tip to bring it in balance.  I think I can fix that with a little extra glass or some lead in the hub.  It turned out that the profiles cut by the prop carver and templates were pretty close even though I tried to cut them 3/16" fat.  If I do another one, I think I'd draw the template airfoils about 3/16 bigger and just cut a bigger airfoil, then work down to the desired size.  The leading edge was somewhat irregular; a little more care, practice and a different cutter would likely help that.

[Kent Ashton]

Glassing my prop:  I have had luck before using a flox trailing edge about 5/16" wide.

 

I marked a 5/16" line, put a strip of peel ply down using alumium tape on the other side to keep the PP in place, then glassed.  (pics 1,2)  After the glass  hardens, cut and chisel the wood away (pic 3).  A better idea might be to cut most of the TE through but leave enough uncut that it will support the glass.  That'd be a lot less work removing the TE wood.

 

I also relieved the leading edge to allow for a BID overlap without making a bump but probably removed too much. (pics 4, 5).  The relief is larger on one side to fix an imbalance.  I'll use a little more glass in the overlap there.

 

So far, the balance is pretty good.  I thought I'd need a half oz at the 75% span but with the first glassing, it has needed less.  I think I can make that up with the final glass.

[Kent Ashton]

Prop is glassed.  The process I used (well, not exactly but close) is to (1) relieve the cambered leading edge for coming overlap, (2) partly cut the TE wood to make removal for the flox TE easier later, (3) layup UNI + BID on the cambered side, flip the prop, (3) remove the TE wood for the flox corner then (4) layup UNI + BID on the flat side overlapping the BID layer onto the cambered side.   Peel-ply used on curing layups.  I have filled with West + micro.  I'd rather have used a building epoxy + micro but I had a lot of West to use.  Must investigate a gel coat next time.

 

This layup schedule is just a wag.  Some fellows use a lot more layers.  Some use more layers and also build-up UNI spars.  One well-known builder says he does not glass the flat side.  I can see where you'd omit that if you anticipate trying to repitch props for people.  When you consider that wood alone is good enough for many props, there is probably some flexibility here.

 

The blade balance has been pretty close all along but all my imbalance --a lot!--seems to be in the hub, which takes about 2oz to balance.

[Kent Ashton]

The prop is painted.  The finish could be better--hell, it can always be better!  I have learned the hard way that when you think the filler is perfect, spray a mist of black sandable primer on the object and sand it all off.   It will reveal all the missed pits and sanding scratches for further sanding or refilling.  However this time I figured that a prop gets beat up anyway so I would just prime it and paint.  It's a satisfactory 10 foot paint job.

 

Balancing: I got the balance near perfect using my static balancer (pic above) but I thought I'd also check it with and easy-to-make hanging balancer (pic 3) (See PDF drawing attached and Contact magazine, issue #84).  This became somewhat confusing from not fully appreciating the dynamics of the hanging device. 

 

First, the position of the moveable ferrule inside the tube determines the sensitivity of the balance (pic 4) but if the top of the ferrule is positioned below the CG of the unbalanced prop, the balance—even with the perfect weight— will be unstable and never stay centered up.   So start with the ferrule positioned high in the hub and move it down for more sensitivity.

 

Then there is the question of which side of the hub to install the weight, or to split the weights on each side.  Normally I don't think it matters but it's worth considering.   See pic 5.  If one face of the hub (or prop) is heavy, installing the weight on that face of the hub will minimize a coupling imbalance as the prop spins.  To determine which face of the hub/prop is heavy, if any, position the ferrule opening in the center of the hub.  If the prop can be balanced but does not remain stable and centered, the prop CG is likely in the “case 1” position.   If the prop can easily be balanced and remains centered, the prop CG is likely in the “case 2" position.  Install the weight on that side corresponding to the CG position to minimize coupling imbalance.  

propBalancer.pdf

[Jon Matcho]

Impressive Kent... I'll be sure to come back to these posts if I ever get the urge to do this.  I see a familiar name on that prop balancer PDF attachment -- Patrick Panzera.

[Sammac91]

Hi Kent, do you have any more info on your nose retract?

Cheers,

Sam

[Kent Ashton]

Pilots like barbecue, right?  Back in this post I showed my homemade smoker

http://www.canardzone.com/forum/topic/18661-kents-long-ez-project/?p=59288

 

It worked but took a lot of charcoal and tending.  Since then I bought one of these Akorn Char Grillers.

https://www.chargriller.com/kamado-grills

 

Lowes has them on sale for $250 right now, less than half the price of a Big Green Egg and they work just as well.  Load it up with charcoal (I use briquets), it comes up to temperature in about 20 minutes.  You put on your ribs and after some small air adjustments it will hold a temperature for hours while you build parts.  After three hours of smoking you will only use 1/3 to 1/2 of your charcoal.  There are lots Youtube videos.

 

Pic: smoked a chicken here but ribs and brisket are better.

[Barry]

After getting steered to this thread by Kent,

 

just amazing what Kent and the rest of you can do.

[Kent Ashton]

The internet is a great resource. You can do things you never would have attempted back in the old days. Thanks to folks like Jon who make it possible.

 

BTW, Jon, what was your motivation for starting CanardZone? Certainly not money!

[Jon Matcho]

BTW, Jon, what was your motivation for starting CanardZone? Certainly not money!

 

The first incarnation of the Canard Zone was started by Nick Ugolini as an alternative to the email lists, originally attached to Nat Puffer's www.cozyaircraft.com site.  When Aircraft Spruce announced the purchase of Cozy Aircraft from Nat, Nick put out the word that he wanted to transfer ownership of the site so that it would be independent of Aircraft Spruce and would remain a community resource.  Being a full-time Internet guy I submitted my offer to build and host the new site.  Nat and Nick passed the baton and the Canard Zone was officially launched on December 17, 2003 -- 100 years to the day after the Wright Brother's historic first flight!

 

Being a new builder at the time my interest was only to ensure that I would be able to read posts like yours!    My interest now is essentially the same:  to support sharing information, to attract new members, builders, and flyers, and to make the Canard Zone the go-to place and directory of all things relating to experimental canard aircraft.

 

Can't be that hard   ... thanks Kent!

[Kent Ashton]

Ah-ha, a page from 2004 above.  Interesting history.  Hope you have made plans for CanardZone when you go to that big hangar in the sky.  :-)

 

Time flies.  I remember using dial-up internet in Alamogordo, NM in the late 80's, when I had to call Las Cruces for a hook-up and wait for the beeps to settle down.  At that time, the only aviation site available (as I recall) was rec.aviation.homebuilt.  

 

I finally got my Basic Med done and got back in the air Saturday after being grounded for about 9 months. In some ways, not flying is a lot easier than flying.  Bought a newer Ipad Mini and updated my Foreflight subscription.  Renewed the condition inspection.  The Cozy flew just fine.   Now I need to wash the EZ and take a few sale pics.

[Jon Matcho]

Hope you have made plans for CanardZone when you go to that big hangar in the sky.  :-)

Woah there, slow down. I'm in my prime!  Yes, turnover of the Canard Zone is actually covered in my will (for whatever reason this has been criticized elsewhere) where I maintain a list of potentially interested parties that would be presented with the option to run the site. I don't actually expect it to get that far before I figure out a way to transition into community-based management.

 

At that time, the only aviation site available (as I recall) was rec.aviation.homebuilt.

Wow, blast from the past.  Still alive, but on life support:  https://groups.google.com/forum/#!forum/rec.aviation.homebuilt

 

I finally got my Basic Med done and got back in the air Saturday after being grounded for about 9 months. In some ways, not flying is a lot easier than flying.  Bought a newer Ipad Mini and updated my Foreflight subscription.  Renewed the condition inspection.  The Cozy flew just fine.   Now I need to wash the EZ and take a few sale pics.

 

Congratulations, well done. Now you're in your prime too!

[Kent Ashton]

Finally got a chance to test the new prop and was pleased with it.  It seemed to run smooth with no noticeable vibration.

 

The engine does not overspeed on takeoff and climb.  At 8500 msl, 7 deg C, 2650 RPM. leaned to peak power I was seeing 136-140 KIAS (157-162 KTAS) on my uncalibrated ASI.  This is roughly 10 knots faster than my old underpitched prop and comparable to my friend Mark's Hertzler prop which he allowed me to test.   The main thing is that I didn't have to baby the engine to keep it from overspeeding.

 

I shall call her an "Ashton Blue Blade".  :-)

 

 

[Voidhawk9]

Sound good, and looks great.

[Jon Matcho]

Wow, that is impressive Kent.  Is there a test phase you need to go through with the new prop?

[Kent Ashton]

Is there a test phase you need to go through with the new prop?

 

Ha!  Thanks for reminding me, I was getting ready to put an ad in Barnstormers.

 

Yes, a new prop is generally considered a "major change" that requires putting the aircraft back into Phase I.  See Part 21.93(a)

https://www.gpo.gov/fdsys/pkg/CFR-2011-title14-vol1/xml/CFR-2011-title14-vol1-sec21-93.xml

 

5 hours per my Operating Limitations.  Some O.L.s may require more.  Dang, I'll just have to go fly this week.  :-)

[Barry]

That is phenomenal Kent.

 

I think, beside the skill to build, it requires a lot of confidence to test your own prop...

Edited June 29, 2017 by Barry

[Kent Ashton]

Covers:  I have made several and enjoy the process.  I use one of the lighter grades of Sunbrella for the main cover and make an inner liner over the canopy out of fabric similar to this flannel fabric from Noah.    http://wiki.shopperoutletnetwork.com/index.php/Covercraft_Noah_Barrier_Fabric_Custom_Fit_Vehicle_Cover

 

I stick the inner cover to the main cover with three velcro patches.  When I stored my Cozy III outdoors, I made a full cover (pic).  Yeah, that was a little anal.  :-)  Below is a traveling cover for the EZ.

 

I start by taping paper to the canopy to make a paper pattern and cut the pattern as shown in the pic--this is my Cozy IV pattern.  Then it's a matter of sewing the canopy sections together, put it on the airplane and adding more fabric.  Fit, cut, sew, repeat many times.  You need an industrial machine for this.  A "walking foot" machine is best.  I started with an old craigslist Singer industrial machine but it sewed at lightning speed--too fast.

 

This pattern making technique is similar to making "flexible shape patterns" used in the process of English-wheeling auto panels.  There are some good Youtubes on it.  Good to know if you every want to duplicate a three-dimensional curved surface.  http://cyclesource.com/newsblog/?p=27979 

[Kent Ashton]

Nose lift motors:  The Wright and Wilhelmson nose lifts use Thomsen Electrak PPA motors.  pp 22-23 here

https://www.thomsonlinear.com/downloads/actuators/Linear_Actuators_G_cten.pdf

Wright's design used the whole Thomson shebang.  Wilhelmson developed a lighter ball-screw design that was more compact.  It seems that there were two versions of the motor floating around, an 18:1 ratio and a 58:1 ratio.  The 18:1 ratio runs up and down faster but doesn't have as much mechanical advantage (leverage) as the 58:1 ratio which moves slower.  This I learned the hard way by ordering a Thomson part and having to buy a second motor.   You can find them on ebay sometimes.  The ratio is shown on a sticker on the motor.

 

In addition, the same motors come with or without a manual drive shaft sticking out of the top of the motor.  I learned this one the hard way too. 😞   But I managed to swap some parts and get a 58:1 ratio and the manual option.  For now, I'm not connecting the manual option on the Cozy.  It seems unlikely I would encounter a failure where the mechanism would not extend.

 

They are often called "slide out" motors because they're used to operate the slide-out rooms on recreational vehicles.

 

BTW, the Wilhemson schematic looks rather complex.  My buddy recommended this relay which is very simple to wire-in and seems to work fine

http://www.elecdirect.com/cole-hersee-switches/cole-hersee-solenoids-relays/forward-reverse-relay-module-for-intermittent-continous-operation-70aat12vdc-intermittent?gclid=CKeB8LzO5M0CFdgKgQodAp0CgA

 

On the EZ, I just use the 'ol plans crank.  I can see no need for electric gear there.  The Cozy was starting to hurt my back.

Edited August 26, 2022 by Kent Ashton
update PDF link