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ArcticDave's Legal Eagle XL

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Hmmm not sure why that pic came up twice?

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Posted (edited)
On 3/15/2019 at 4:16 AM, rossfi said:

Hi Dave,

               Been going through this blog since I found it and thought I'd ask a question if you don't mind (& given your mechanical skills) - and the question is this; Why does everyone cut the VW engine to make a boxer twin? i.e. Why not just remove the cylinder heads from one side, block up the holes, re-balance & fire it up as an inline twin? . . Something to do with the angle of the dangle on the crankshaft?

Also I noticed you've widened the top of the air-frame where the wings attach (which looks Much betterer :-) but haven't added any diagonal bracing to the rectangle/squares formed in the  mod. I know there are a few designs that don't but have also noticed a lot of designs that Do - And given that your wings attach there, there may be some twisting forces (yaw) from potential wind gusts to account for???

Hi Sydney!

I don't mind the questions a bit.

1) Firing order is perfect for the opposed twin configuration. VW Type 1 Firing order is 1-3-4-2, of which #'s 3 & 4 become the new #1(3) and #2(4) cylinders. Also weight is another key factor. Your inline twin idea would require a full length crankshaft and camshaft, along with some hefty counterweights to compensate for the missing cylinders on the opposing side...adding several pounds.

2) Good eye on the top structure! I will be adding diagonals to both of those boxes. Just haven't got to it yet. 

If you check out Eagler's Nest forum there have been a couple built by guys down in OZ. If you get on that forum look for a guy named Grant. He built a Double Eagle and used the full engine. I can't remember what part of the country he was from, but he really enjoys flying his. 

https://www.eaglersnest.com/forum/

 

 

I have been really sick for the last few weeks and am finally getting to the point I can actually talk again.(Lost my voice almost entirely for a couple of weeks) The weather is warming up after the last cold snap, so work begins again. I CC'd my heads this morning and am carving out some extra chamber volume today.

 

 

Edited by ArcticDave
added current progress

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Oops...got the firing order wrong! 1-2-4-3 is the correct and we're using #2 and #4. My mistake :tisk-tisk:

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Posted (edited)
On 3/16/2019 at 12:50 AM, rossfi said:

LOL - Not too fussed about the "Aesthetics and Machismo" to start with but not real keen on the bumpy ride idea either. As it happens I just had the same conversation with a mate in Melbourne who tells me it would be cheap enough (??) to get a new crank made up from scratch. Advantage is that if I want to restore to 4 cyl (by way of a power upgrade) I can by replacing original crank and opposite head assembly. VW engines are available here but not as much as in your neck of the woods, so tend to be expensive.

OK Homefire - I'm not sure of how much you already know :idunno:so I hope the following info doesn't come out sounding like a 'lecture from on high' - if it does please excuse me in advance, I'm doing/writing lots of assignments, presentations and lesson plans atm  . . . :00000067:  

I noticed that at the moment you are using the Mega 2650 as the 'brains' for the basic EFIS/EMS functions and I wondered if it will have sufficient capability for what you want to do? Or at least for for the additions you are likely to want make over time. While the 2650 has lots of IO and is 'cheap as', there has been a lot of development since that board came out and there are a lot of alternatives (likely with cheap Chinese clones) that may have more available processing power to handle the workloads (hate those 1201 errors :yikes:). 

As you'd know the Arduino platform (& the IDE) was originally designed around the 8 bit AVR processor platforms (including Uno & Mega2650). Since then the IDE has now been expanded considerably (& sometimes copied outright) to include a much wider range of processor/platforms, many of them 32 bit with gobs of memory & I/O as well as massive speed increases. One example of these is the 32 bit PIC processor made by Microchip, a US company with a very long pedigree (and which has just bought out AVR). An example of two boards made by Digilent https://store.digilentinc.com/processors/processor-boards/ is shown below (both based on the PIC32).

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I have the bigger of the two which as you can see is very similar to the full-size Mega (with even more I/O) and which is why I really sat up and paid attention when you posted the mini EFIS info. Sadly I've not seen a clone of it similar to the 'Mini-Mega'. 

There are other boards and of course there is the Arduino Due itself, but it is a bit of a moving target and its hard to know which will last the distance (see the Maple project  https://www.leaflabs.com/maple - have just found out they are now 'discontinued' but heaps of Chinese clones out there based on the same STM32 chip, now likely to be orphaned). The "Teensy" boards https://www.pjrc.com/teensy/ can also be programmed by the Arduino IDE and they have been around for a long time with pjrc contributing to the Arduino knowledge base.

The beauty of the new Arduino IDE is that you should now be able to change the underlying platform with relative ease, though there will always be glitches :cry2:and some work to fix it :miner: 

There is also another platform altogether called the 'Micromite' http://geoffg.net/micromite.html which started some years ago as a series of publications in a local electronics magazine by a guy call Geoff Graham (from West Oz) which is also based on the PIC 32 platform but which uses a clone of GW Basic for programming (it also allows inline 'C' programming). There has been steady development over a number of years much of it previewed on a forum called "The Back Shed" https://www.thebackshed.com/forum/forum_topics.asp?FID=16.

One of the people who has made some significant contributions is a guy called Peter Mather from the UK who seems to be a genius at 'C' programming and PCB design (I think he is planning on building a plane too). Peter wrote some inline C code for an EFIS on the Micromite and you can see the working device here https://www.youtube.com/watch?v=SQ_h7oSppGk. Brightness is still an issue but with OLEDs around the corner  . . . . so one to watch . . . (some of the latest conversations are around PIC chips with clocks running in the 200MHz range).

There is a mob over your way that sells a couple of Peters PCB designs that have built in LCD controller interfaces as well as Arduino hardware footprints for very reasonable prices http://www.circuitgizmos.com/Micromite-Devices-c14171441. I bought a couple to 'play' with but sadly am just too busy atm :cry2::miner::miner:

There is a fair amount of crossover between these two platforms now and it's relatively easy to change the boot code on a Microchip PIC32 for either platform.

I don't know if any of the above will help you and Dave but it should keep you browsing for a while and may yet help at some point in the future or give you some ideas. At any rate I hope you find some food for thought . . . :pop::oregonian_winesmiley: 

Well this has been a nice diversion But it's back to the grindstone for mee . .  sigh

 

 

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The world of Single board computers has gone Crazy .  My first ""COMPUTER"" was a ZX80 followed by a ZX81.   Thought I was TOP DOG when I upgraded to 16K of Ram.  Now days a lowly  Arduino seems to  Eclipse all that.    Even the ZX81 had more computer power then got us to the moon, these new single board computers are CRAZY !  There really doen't seem to be a end to this stuff today, eaaa?   

  The EFS Flight toy I was working on for Dave proved to be well above my feeble programing skills.   I currently have a friend in Serbia of all places working on the project.  If ever complete Dave's creation is going to have the dribbles and Contents of a International Consortium  of efforts , parts and doings.  LOL   WELL more computer then ever got man to the moon the fist time.  

 That system is quite interesting and I will follow up checking it out for sure.    My next toy is going to be a Raspberry Pi Zero W I think.  $10.00 and does way more then I need right now.  Check this chit out ?   INSANE I tell ya !    I copied and saved all those links you provided to investigate in a while.  Thank you Sir !

 

 

Edited by homefire

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Hi Dave,

Sorry to hear you've been unwell but good to hear that you seem to be on the mend - and you've got summer coming! :thumbsupanim 

1st up thanks for the answer on the motor - the weight part makes sense and my mechanic mate who I mentioned earlier had a quick look on the internet and picked up on it real fast then explained it to me - He seems to have taken an interest and says he wants to build one - the engine that is - just cause he likes the 'sound' of it :rolleyes: - (he has no interest in flying and thinks I'm :nutty:). At any rate I may have a helper if I decide to move forward on this. 

2nd - No probs on the spotting - glad to help. The diagonal bracing thing is interesting. I noticed that Leonard has used triangles extensively which seems to be standard practice but I've also noticed he hasn't used it on the wing struts going back down to the fuselage (as in the Kitfox, Carbon cub etc) - it could be a 'distribution of forces' thing - more thought/research required.

Thanks for the 'hint' on the Oz builders and the Eaglers Nest - I did have both on my 'look into' list but your prompt got me looking and I must say Grant's machine is Very nice indeed.

I've also found out as a result that the Legal Eagles are an 'approved design' here which cuts down on the paperwork some - if you build exactly per the spec - but of course my reason for wanting to build it is that it's such a good basic platform and I can see so many opportunities to test ideas (meaning design changes so more paperwork . . sigh :aw-shucks:).

Speaking of design changes I've noticed to that you've made the tail feathers out of wood - which is another change you've made that I like and seems 'right' - is that aesthetics? a weight thing? does W&B become an issue?

For my part I was thinking of flipping the back end of the fuselage 180_degrees so that the flat part of the triangle is at the top giving me a bit of a flat surface to work with at the back to mount the tail-feathers and hopefully removing the need for wire bracing?  

 

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Hi Homefire,

Yes you're right about that - the number and variety of systems out there has gone crazy indeed - makes it very hard to pick the 'winners' . .

For my part I still like the Arduino platform it's just so intuitive and quick to test ideas on or knock out a quick solution. Thing is that when the job gets complex you still have to knuckle down and do the hard yards - in detail . . sigh (I want to build an electronic ignition control - but even a basic one is fairly complex coding).

Good thing is that there are plenty of others leading the way developing & sharing code that can be leveraged & as I mentioned there is a bit of crossover between Arduino & Micromite which could create potential opportunities. 

You're lucky to know a Serb programmer mate - those guys are generally Superb at coding! :thumbsupanim

One of my mates gave me a 'broken' Rasberry board a while back - turned out it just needed the Operating System to be reloaded. Worked fine after that so I gave it back to him. I did find that the video was a bit slowww however . . . No surprise really, hard to fit a video accelerator and extra memory on such a tiny board. After some thought I realised it wouldn't do well on aircraft electronics though (EFIS, Engine Management/Ignition) as the versions of Linux used are not (as far as I know) Real-Time-Operating-Systems (RTOS). 

Have fun with all the links - it is a fascinating subject . . Now if I could just find a CHEAP high-brightness Colour display . . . . .:89:

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17 hours ago, rossfi said:

Hi Dave,

Sorry to hear you've been unwell but good to hear that you seem to be on the mend - and you've got summer coming! :thumbsupanim 

Thanks...I'm happy to be feelin' better!

1st up thanks for the answer on the motor - the weight part makes sense and my mechanic mate who I mentioned earlier had a quick look on the internet and picked up on it real fast then explained it to me - He seems to have taken an interest and says he wants to build one - the engine that is - just cause he likes the 'sound' of it :rolleyes: - (he has no interest in flying and thinks I'm :nutty:). At any rate I may have a helper if I decide to move forward on this. 

2nd - No probs on the spotting - glad to help. The diagonal bracing thing is interesting. I noticed that Leonard has used triangles extensively which seems to be standard practice but I've also noticed he hasn't used it on the wing struts going back down to the fuselage (as in the Kitfox, Carbon cub etc) - it could be a 'distribution of forces' thing - more thought/research required.

He did it that way to distribute the forces generated by the up and down g forces on the wing. By splitting the wing struts, that load is split between two separate cross-members at the bottom of the fuselage... instead of just one. He probably was able to use lighter tubing because of it.

Thanks for the 'hint' on the Oz builders and the Eaglers Nest - I did have both on my 'look into' list but your prompt got me looking and I must say Grant's machine is Very nice indeed.

I've also found out as a result that the Legal Eagles are an 'approved design' here which cuts down on the paperwork some - if you build exactly per the spec - but of course my reason for wanting to build it is that it's such a good basic platform and I can see so many opportunities to test ideas (meaning design changes so more paperwork . . sigh :aw-shucks:).

I chose the Eagle for the exact same reason!

Speaking of design changes I've noticed to that you've made the tail feathers out of wood - which is another change you've made that I like and seems 'right' - is that aesthetics? a weight thing? does W&B become an issue?

Cost,cost,cost. I saved over 70% by using wood instead of aluminum. I never really cared for the shape of the Eagle tail anyway. Mine is a scaled down Pietpenpol Air Camper tail. I think it matches the blocky Eagle better.  My bush style landing gear and tundra tires are several pounds heavier, so I needed extra weight back there to get the w&b right. Saved money and it corrected the w&b without resorting to lead weights. It is about 6-7 lbs heavier than the plans version.

For my part I was thinking of flipping the back end of the fuselage 180_degrees so that the flat part of the triangle is at the top giving me a bit of a flat surface to work with at the back to mount the tail-feathers and hopefully removing the need for wire bracing? 

I see what your thinking, and it could be done that way I think. You would have to significantly beef up the spars in the horizontal stabilizer, but that could make the tail section easier to remove...if that's what you're going for.

 

 

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I cut down my rocker shafts today and drilled both stands for alignment pins. I am going to try and beg some lathe time from a friend in order to cut oil passages around the rocker shafts next week. 

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Seriously IMPRESSED on your abilities there  Dave.  You seem to have a knack at coming up with a way to do the impossible with Nothing to Work With.  You must have had some form of  Military service behind ya ??? ? 

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11 hours ago, homefire said:

Seriously IMPRESSED on your abilities there  Dave.  You seem to have a knack at coming up with a way to do the impossible with Nothing to Work With.  You must have had some form of  Military service behind ya ??? ? 

Thanks Homey!

I did come from a military family, but the closest I got was ROTC in high school. I wish I had stuck with it sometimes. :aw-shucks:

My grandfather, Clyde Voak, was an ace mechanic. He was also a Flying Sergeant during WWII. He flew a C-47 transporting wounded soldiers back to England from the European front. Pop was always my hero, and still is today, even though he has been gone for many years. He taught me how to work on stuff...and make do with what you had. :worship:

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Cylinder head progress.

Cut donor end sections from an old head. I then soda blasted the the pieces. You can see in one of the pics how nasty the old head was. I will notch the new heads to accept these end caps next and weld them on.

I also was not impressed with the air passages that are supposed to cool the exhaust valve. Some were not even open. I drilled every one them out to 3/16" for better airflow.

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Your doing stuff here I never would have even imagined ever possible Dave.  No Clues Aluminum could be worked like this.

Yep, all the stuff like the oil passages and what not can be addressed here and now.  All that little extra details

Could be the difference between Staying in the air or forcing down some place in the rocks.   By Dang your going to know every nook and cranny on this engine for sure. 

 

Cool Beans Sir!

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I skimmed over this stuff on the first set of heads I made, and I wish I hadn't. This log has been useful a couple of times, when I forget what I did to some part I made.

This is technical to an extent...so just change the channel if you like. :zzzzz:

I decided to get my combustion chambers in order next. Chamber volume is a critical measurement for any engine...a custom engine doubly so. I started by performing an initial volume measurement = 59cc

Target = 66cc

How did I arrive at 66cc? With the handy CB Performance calculator!

http://cbperformance.com/v/enginecalc.html

I removed all the hardware from the heads at that point and began assessing where I want to remove 7cc of aluminum from my combustion chambers. I installed my copper head gasket and marked it out with a sharpie. I can take out anything up to that line. You will see in another pic the red is where you remove material, the blue area you really try and leave alone, as that is the quench deck. It is generally accepted that a deck height of 40-60 thousandths of an inch is a good target zone for reaping the benefits of piston quench. This engine has a .055 thou deck. I could get it down to .040 by spending more cash, but at some point you have to draw a line. :nutty:

As of now, I am roughing out the area with the die grinder and an aluminum bit. Every so often you have to reinstall the valves and spark plug to measure volume again and again and again and again...:arrowheadsmiley:

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Posted (edited)

I would think it's a bear trying to keep every symmetrically EXACTLY the same. Even a half a thousandths can do strange things in a Combustion chamber. Dang Dave ! Yea was spitting out words way above my pay grade. I had to look em up !

 

 

""" Posted by T.O.O. on June 21, 1998 at 12:05:53: In Reply to: What is "quench"? What is a "quench area" Why is it good? n/m posted by body on June 21, 1998 at 10:09:42: Quench, or squish area is typically the flat area on the top of the piston that's almost level with the top of the block deck. It must have a corresponding flat area on the deck surface of the head to qualify as quench. If you look at a combustion chamber, you will usually see these flat areas, and they will have the volume of the actual combustion chamber between them. When the piston is compressing the mixture, as the piston nears the head, the flat areas on the head and piston come together and force the mixture from those areas to "squish" into the chamber, where the spark plug and burning mixture reside, so you achieve a more complete burn. The quench area also runs cooler than the rest of the chamber / piston. These lower temperatures are where the "quench" comes from. When properly designed, the quench areas can have a tremendous effect on the quality of combustion, and allow higher compression ratios, and due to this they are considered "artificial octane" by scientific types. Bottom line is "properly designed, quench is good". .......................................T.O.O. ....................................... ps. As it is like (more octane), and promotes a better burn, why do the turbo people do away with it?? Go figure. """

Edited by homefire
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Quench is definitely a beneficial thing! There are a lot of Vw engines out there with huge deck heights and zero quench, and while they run ok, It is not the best setup. That bump in compression ratio and cooling can make a huge difference in "seat of the pants" power. It makes for a much snappier and cooler running engine.  :)

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Done with chamber volume expansion!

After a lot of shaping, the head chambers are done! I went with 65cc instead of 66cc. That will give me a static compression ratio of 8.6:1.

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The cylinder heads are as far as I can go now. All the pieces are made and fitted. Once I've saved enough money to buy or rent an argon tank...I can weld it all together. In the meantime, I can resume work on the fuselage as it is almost ready for paint. I just want to add a couple gussets and other small things before spraying the primer coat.

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Super Stuff Dave.    What you thinking color scheme wise ?   Camo ?  Red Baron ?  Snoopy ?  Doing Flames Coming out of the Engine Cowling ?  Errrrr Nawwwww Better not go there.

 

 

Paint.jpg

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God... that is a beautiful car!

Orange and black will be the colors Homey. Orange wings and tail with black fuselage tubing and hardware. Should look sharp...if you like orange. :)

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6 hours ago, ArcticDave said:

God... that is a beautiful car!

Orange and black will be the colors Homey. Orange wings and tail with black fuselage tubing and hardware. Should look sharp...if you like orange. :)

Sounds like a Plan.    Not troubles seeing those contrasting the sky.

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18 hours ago, homefire said:

Sounds like a Plan.    Not troubles seeing those contrasting the sky.

It will be nice and bright. Gotta make it easy for the search party to find me:inocent:

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1 hour ago, ArcticDave said:

It will be nice and bright. Gotta make it easy for the search party to find me:inocent:

Hopefully on it's maiden flight you are not turned into a crash test dummy!!

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Hi Dave,

This is a great thread  and you have done a very workmanlike job, my hat is off to you....  I was recently investigating methods for welding or soldering aluminum and alloys, short of the TIG method what process are you going to be using to put the pieces of the head together?  Or are you going to use TIG?

Again great job and thank you for bringing us along for the ride, err, pre flight......

Jeff

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I say paint it sky blue. That way you will be stealthy in the sky and it makes it easy to find you on the ground.
Just kidding. Dave I think your doing a great job building your plane.I'm watching and learning too. 

BTW if you ever decide to part with that anvil let me know.
AzNuggetBob

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17 hours ago, pairadiceau said:

Hi Dave,

This is a great thread  and you have done a very workmanlike job, my hat is off to you....  I was recently investigating methods for welding or soldering aluminum and alloys, short of the TIG method what process are you going to be using to put the pieces of the head together?  Or are you going to use TIG?

Again great job and thank you for bringing us along for the ride, err, pre flight......

Jeff

Thank you Jeff. :)  I will weld it with a 240v Mig that belongs to a friend down the road in Wittmann. He has a spool gun, so I just need to come up with a bottle of argon and a spool of er4043 aluminum wire. I tried welding it with my torch, but the  head dissipates heat so fast, I just couldn't get it hot enough...even preheating the heads to 400 degrees. I think a TIG would be the same. It would require a huge TIG welder to have enough amps to do a good job of it.  I got some thinner aluminum to weld beautifully with my torch, but the cylinder heads have too much mass right where I need to weld.

31 minutes ago, AzNuggetBob said:

I say paint it sky blue. That way you will be stealthy in the sky and it makes it easy to find you on the ground.
Just kidding. Dave I think your doing a great job building your plane.I'm watching and learning too. 

BTW if you ever decide to part with that anvil let me know.
AzNuggetBob

Thanks Bob! It has been a long road for sure, but I am proud at what I've gotten done so far. 

That anvil has a permanent home.  :D

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