After a much too long break from working on the airplane, I'm back at it again. Not much has happened over the last couple of months in the shop. Returning to shift work has been harder to adjust to than I anticipated. Add to that the passing of my Mom, Linda in October and all the things to process both emotional and tangible - it's been tough to concentrate on anything else.
Mom was always one of the biggest champions of my dreams, including flying. She was my first passenger when I got my licence in 1995. I told the story of that day at Mom's Celebration of Life as it was one of my favourite memories of many during times I spent with her.
We went flying on a beautiful early spring day in a Cessna 150. Typical first passenger type of flight, showing off my newly minted licence by taking a tour of local sights from above. It was beautiful.
Mom always appreciated a good joke. When we were turning base from downwind, I pretended to look around the cabin like I'd lost something. Of course, Mom asked what I was looking for, to which I quipped "There should be a landing checklist in here somewhere, I might have forgot to bring it".
The look on Mom's face was priceless as she went from surprise, to fear to sly recognition that her oldest son was just trying to pull a fast one. Fast transition! She punched me in the arm and reminded me that landing checklists are important and I should have it memorized. I'm not sure she ever truly forgave me, but she probably did. She was that kind of person; kind, forgiving and loving. I miss her very much.
I also know she wouldn't want me to delay getting my plane built, even if she never got the chance to see it or fly in it. So this week I got back at it.
Work continues on the elevator and horizontal stab. There are lots of little things to complete, but it's coming along nicely. In order to mate them up, I had to finish adding the fences on the stab. Here they are lined up where they will be fastened on the stab. To ensure that both ends are exactly the same, I taped them together and dry fit them, marking out the rivet lines:
Quick fit check on the other end, before drilling A3 pilot holes through both
Pilot holes drilled then clecos to hold it in place to confirm measurements are correct and fence is equal all around the stab aerofoil:
The fence is 063 thick, same as the original outer hinge plates which are attached at the trailing end with A5 rivets, so I'm doing the same here (where the black clecos are). The A5 holes are already in the tip rib, so I used the rivet hole duplicator to match drill them on the fence. The balance will be A4 rivets. This combination will only improve the strength of the whole assembly.
Happy how the fence cleans up the whole end of the stab:
I flipped the stab over to make getting at the A5 holes easier
Once flipped, I noticed how tight the fence is to the tip rib skin rivets. I made a note to remind me to river the skin first!
With both fences attached, the stab looks real good!
With the stab fences in place, now I could place the elevator in line and see how they line up:
Even without the elevator nose skins on, I was real pleasing to see them "together" for the first time. Have lots to do yet, but it feels good to see the sum of the parts looking close to what they will be once done.
Also important was seeing that the measurements of the centre hinge is correct! It's a tight fit tolerance but I nailed the measurements perfectly! (Picture is not very clear, sorry. Just noticed the camera focused on an errant rivet stem)
I placed the elevator horns temporarily in place to confirm the alignment - all looks good.
BINGO! Correct spacing for the hinge bolt and bushing. So satisfying to know everything is correct!
Next I decided to take care of the elevator cable pass-through hole. It starts with drawing a centreline on the leading edge of the stab and a measured horizontal where the cable guard angle will be riveted on. Thank goodness for flexible rulers!
Sketch out the lines where the slot will be and draw the circles that make up the ends of the slot:
Pilot hole to prevent tearing of the aluminum - that would really suck!
A small step drill bit used carefully does a great job. With both holes done, simple straight cuts from edge to edge on the new circles to open up the slot.
The leading edge of the stab has a slight curvature to it where the cable guard mounts. So once I had the guard angle bent, I rounded it out a bit to match. This will be primed before riveting to the stab:
Not a bad prodcuctive couple of hours. Like I said above, it's nice to see the sum of all the little parts I've done and it's motivating me to get back in the shop.
Next up, nose skins and tackling the trim tab. I've managed to write some good code for the trim tab Arduino computer that will control the servo.
Thanks Mom and thanks to my wife Brenda for getting me moving in the right direction again :)
Not a huge update, but a few things to mention this week.
Ron and I got further along on the 701 wing repair the last two weeks. We are being really challenged by the mistakes of the previous builder's measurements and decisions on what was "good enough". We've compounded that by adding the wind extention, but we are getting it figured out.
The flap extension to match the new wing length is coming together nicely. Because this is an add on, wrapping the short flap skin is certainly fun...
Once we get the flaps skinned we can fix the spacing of the flap brackets. As most things on this repair, nothing is consistent, even between both wings. Having the flaps apart allows us to adjust where they meet the flap brackets. Make it right has been the goal all along.
The days lately have kinda blurred together with my new position at work, but I'm certainly not missing the shift work that's for sure. It has made it somewhat difficult to focus on my project, but things will improve soon as I adapt to my new job and this Monday to Friday schedule. What hasn't changed is the feeling I'm doing something great when I do get to the shop, even if Ron and I spend the hours just jawing about airplanes and flying.
I've long been following the online musings of William Wynne, the Corvair expert I've mentioned before. He wrote the following quote on his blog the other day and it really struck a chord with me:
“Hours in the shop working with your own hands cleanses the part of your sanity which modern life soils”
Indeed William.... indeed :)
It's safe to say that any flying machine is a collection of parts that are strategically placed and assembled to enable one to fly.
Although this is true, it's the little things that get accomplished over the course of a building project that make the difference in not only getting the plane built, but improves the overall quality and performance of the end product. It also contributes to the philosophy I spoke of last August on my blog: ( a-little-here-a-little-there).
Today I decided to pull out the Corvair heads and have a closer look at them.
You might recall that these heads are 110hp versions from a 1966 car. They are just as I received them from the seller - not filthy but certainly not clean either!
Any engine that is more than 50 years old is bound to be grimy. Air cooled engines like the Corvair have many, many cooling holes factory cast in between the head fins. Being small, they trap everything. Not good as the GM engineers counted on these being clear for optimum cooling. What the GM engineers didn't consider is that casting aluminum or other metals sometimes leaves "flash" where the moulding halves join up during the casting process. Either it was considered to costly to remove the flash or maybe they decided it was good enough. What I have experienced however is the massive range of acceptable "flash" tolerances - some heads have so much the cooling holes are almost closed over. With a small amount of dirt in there, they are effectively closed to cooling air.
Here is a look at the cleaner of the two heads. I've put a lightbulb behind to ease the viewing:
As you can see, the cooling holes are many and this head seems quite good. Some minor flash to clean up but generally good.
The 2nd head, despite being from the same casting lot as the first is terrible! I could only find one hole that was clear and even then it was almost closed over from flash:
Took an hour with a combination of small files and old steak-knives, but I managed to clean out the majority of the gunk from the cooling holes.
Both heads really do need a good pressure wash before I'll be able to remove all the flashing, but this was a good start. Removing the flashing is very important and goes a long way to improving cooling of the heads.
It's these little things that take time, but make a world of difference and counts towards the goal. Along those same lines, my father Jim and I have been working on an important submission regarding my mentor Barry. I don't want to say much yet but it's a little thing that also counts for something. Stay tuned for more on this shortly.
I had every intention of spending the entire day in the shop today. I'd taken the time last week to mark specific "shop days" on the calendar - days that are set aside for the shop and my build. A discussion with Brenda and our girls regarding my build led us to an agreement that these days are next to untouchable on the schedule so that I can make real progress this year. Obviously if something special comes up that can't be scheduled somewhere else my shop day can be compromised by moving it to another day, but the goal is to maintain a regular shop presence.
So, I discovered that "something special" can also includes those days when I physically can't go. Today was one of those days.
Last night at Natalie's Scout meeting, I tried to prove that I could still play volleyball like a 20 year old. A "I-used-a-could-do-that" type of thing. Needless to say I slept poorly last night and felt like I'd been run over by a Russian cargo plane today, so I missed the shop.
After some rest and feeling sorry for myself, I decided I didn't need to go over to Ron's and could at least get something done here in my own shop.
I pulled out something simple to work on - the flaperon rear ribs. These are simple flanged parts, really just smaller versions of the elevator rear ribs I made before (see my previous blog post here).
It starts with lining the forms up on the metal template. Unlike other templates, due to their size they don't have bolt holes for the forms. Just line them up and place the entire sandwich in the vice:
The soft faced dead blow hammer is used to gently form the flange over the edge of the form:
Turns out the flanges are a bit wider than the thickness of the form. With the short top-to-bottom height of these ribs, I had to devise a way to protect them when I inverted the form to bend the opposite flange. To do this, I added two blocks on each side. One of them had a small groove cut in it to make room for the opposite flange but still enough area to hold the forms:
As per the plans I need 8 left hand and 8 right hand rear ribs and I made a conscious decision to do only six right hand ones first in case I mistakenly made a right hand one when making the left hand ones. Hate to end up with extras - that would mean making replacement templates for each one I screw up. It's easy to see how this could happen, glad I thought of it ahead of time. Good trick to remember for later when I start working on all the wing ribs!
It's amazing! With a bit of attention to detail, I managed to bang out 16 flaperon ribs, all of equal dimensions and quality. Really cool.
16 complete ribs.... not bad for a day I didn't feel up to doing anything :)
I also got a new 14 tooth-per-inch blade for my band saw. Installing the new blade was challenging, but I learned on YouTube how to properly set the tension and blade guides for my model. Once I make some of the rougher cuts on the plate aluminum using the big industrial saw at Ron's shop, I can use my fine tooth band saw to make the final cuts.
I've said it before.... a little shop therapy goes a long way :)
p.s. Photo credits to my daughter Natalie.... thanks for making me look good!
A while back I saw the following quote which really sums up building a big and sometimes overwhelming project like an airplane is....
How do you eat an elephant?
I have a lot of time on nightshifts at work to study my 750 plans and as I think of all the things I need to make, decisions on features I think I want to incorporate and how I'm going to make all these the parts, I get a bit discouraged. It is indeed a massive undertaking.
But as I keep being reminded both by others and myself, it's all the small bites that add up.
I find myself spending more time focused on completing tasks than taking pictures of my build which is both good and bad. I'm probably getting more done this way, but it doesn't leave a lot to add to my blog for you readers. Most of what I've done in the last couple of weeks is really just repetitive steps that I've already shared. But here is some of what's been happening.
In my last post I said I was headed back to the "drawing board". Here is the correct plywood I should have been using for my form blocks. Much smoother and knot free!
Each form template gets traced twice in opposite (flipped over), creating left and right side forms. These will be cut out in rought form using a hand jigsaw then cut close to final size using the scroll saw (more on this later).
Ron and I continues on our discussion regarding the wing extensions for the 701 wings I'm helping repair. Now that the main repairs at the root end are done, I can focus on this. Ron wants a 18 inch extension, so that's what I'll work towards.
First we have to remove the "factory" wing spar tip extension. I say "factory" because like a good majority of other "factory" items on this plane, it's really not to "factory" plans. Not the right thickness and missing two critical rivets at the upper and lower spar caps.... sigh. At least this time it's coming off to be replaced with longer ones, not just coming off to be fixed or replaced as original.
The wing spar tip extension isn't considered structural per se, but it is an important component of the wing. It supports the fiberglass wing tip and completes the outer structure end of the wing. Here it is close to it's original position on the end of the spar (I had already removed it at this point but forgot to take a picture):
....and removed from the spar. There appears to be a small wrinkle in the wing skin behind the joint, but that can be fixed easily and will be underneath the new skin extension:
Next we had to decide on how to handle the new wing skins extensions and how they would attach to the old skins. We believe at this point we can get away with a simple overlap with a double row of rivets, but we'll probably add a doubler strip underneath for strength, or even another wing rib. We trimmed the lower and upper wing skins to a convenient length and made sure to leave enough skin outside the last full wing rib. Where the trim line ended up (defined by green frog tape below) is actually a good place for a new rib:
The upper wing skins were trimmed back in the same fashion. Then, using the original plan dimensions I cut a new wing spar tip extension web (actually two, one for the other wing to match), by adding a full 18 inches to the inboard end. I was very important to get these right as they need to be perfectly straight to match the wing spar. After careful measuring, they turned out perfectly! This was also good practice making the long scoring cuts from a full 4 x 12 foo sheet of 0.025 aluminum. I'll be doing the same for my 750 wing spars and tips too:
With a little thinking and practice on a scrap piece of matching 0.025 aluminum, the top and bottom flanges were bent to a perfect 18mm width, leaving the total top to bottom dimension of 209mm, exactly as the plans call for!
We are going to wait on putting in the lightening holes until we see where the new ribs end up. The flapperons will also need to the extended, making another pick up point necessary which in turn will determine where one of the new ribs goes.
Ron keeps reminding me to continue working on my stuff too. So I took some time to make some of the smaller parts needed from some of the "scraps" left over from the 701 wig repair.
It's paying off studying the 750 plans when I can too. For example, I new I had to create 6 full length flapperon ribs and probably had enough cut-offs lying around from the repair I was doing to complete them. But then I recalled that the plans call for 4 full flapperon ribs made in 0.016 thickness and 2 full flapperon ribs in 0.025. I referred back to the plans and remembered that the two thicker ribs are "root ribs" meaning they are where the control rods for the flap actuators attach, requiring something more robust. The other 4 thinner ones are distributed elsewhere in the flapperon assembly. Glad I noticed nd didn't make them all the same!
They use the same templates, so I traced out the other four flapperon ribs on the 0.016 aluminum:
Although almost any thickness of aluminum can be roughly cut out on the bandsaw, a standard office paper cutter works great for cutting 0.016 aluminum sheet. Here I cut as close as I can to the template trace lines, then I use the grinder and hand sanding to bring them to final shape/size:
I'll store these in inventory as they are for now as I don't have the bending forms ready yet and wont be building the flapperons for a while.
To continue towards starting my tail section, I found another couple of little parts I could make up while I had the scrap out. I'm also learning that it sometimes pays to bend multiples of the same part where required. The tail section call for two of these 35 x 40mm bent angles from 0.025, and I had the perfect piece to make it from. After cutting and deburring, into the bender they went:
This way they end up being perfectly matched!
I got several other small parts made as well that aren't pictured here, but like the quote says.... "One bite at a time".
Wonder what's for dessert?
The Google search bots are really going to love my posts now!
Remember my fellow Corvair engine builder Jeff Moores of Newfoundland (see previous post "time-to-get-back-at-it")? While at the Zenair Open House we talked over lunch about the struggles I had been having with head studs and Jeff reassured me that my issues were common issues in both his previous builds. He offered to send me some extra head studs that he had lying around his shop to replace the bad ones from my core. They arrived via mail on Tuesday and they are brand new! All for the price of shipping via snail-mail.
The more I continue pursuing a Corvair as my choice of motor, the more I'm starting to realize the value of getting to know other Corvair builders, both for their experience and generosity. This is the kind of group I want to associate with, not some faceless foreign owned engine maker that just wants my money and couldn't care less about my mission to learn. Thanks Jeff!
Next steps, dealing with the 3 stud holes that need to be fixed (see "progress-sort-of") . I've decided on using TimeSerts which are a threaded barrel insert repair that is accepted in the conversion manual. Definitely more expensive than Helicoils (another possible repair method) but I believe worth the piece of mind. Corvair automotve parts warehouse Clark's Corvairs rents the TimeSert installation tool kit and also sells inserts that are the proper length and a blind nut tool for proper torquing of the head studs. I think I'll order those now and get the repairs done soon in preparation for some case machining work I'm planning.
Got a call from my buddy Guy (correct pronunciation is Gee, which is french Canadian) . Despite his best efforts to remove the broken studs he is struggling a bit. He tried welding a nut to them but they just snapped off further down and now they are sitting close to flush to the block. This leaves no option but to drill them out using a milling machine and end mill bit.
Fussy, temperamental work with a fairly high risk of wrecking the threads if not careful.
After finding limited success using the weld method, he tried centre drilling the stud in preparation to back them out with an EasyOut bit. This proved to be very difficult because the studs are a hard material to drill, but he did manage to centre drill one of the three. The other two he's going to use the milling machine as it should be easier.
The next concern will be how to clean out the remaining debris from the threads that gets left behind. The conversion manual is very specific that the lower end of the studs is a special thread called 3/8"-NC5. So at this point I believe I'll need a 3/8"-NC5 tap to clean out the threads. Even an experienced machinist like Guy had never heard of this particular thread (he checked with his suppliers too) and suggested it will be expensive to obtain due to it's rarity.
While my buddy worked on end milling the holes, I decided do do some research.online. Although I wasn't able to find a tap or die that matached this unique thread, I did come across an online archive of GM production drawings that show the machining dimensions of a Corvair engine! I really love the internet!
This is where it gets a bit more confusing. According to the dimensional drawing showing the machining instructions of the casting, the stud holes are supposed to be tapped to a dimension 3/8"-16 UNC:
But how can that be? The hole and stud should be the same thread as the stud..... hmmm.
I sent an e-mail to the internet Corvair conversion forum seeking some guidance.
Not long after sending the e-mail, I got a telephone call direct from William Wynne (the Conversion Manual author and recognized Corvair guru).
We had an almost hour long conversation about the conversion process, my overall plans and this particular issue regarding the studs among other things. He's very supportive of new builders like me that want to learn and his overall philosophy about home-building and being in the arena speaks to me.
He is an amazing person to speak with and very quickly confirmed that the GM drawings are correct, the stud holes are in fact 3/8-16 UNC. The reason the studs are slightly different is GM engineers wanted an interference (extremely tight) fit to ensure the studs would remain in place. Using a common 3/8-16 UNC tap would be appropriate to chase the debris from the holes.
Guy happens to have that tap (it's common) and I called him afterward to confirm what we know now to be correct. He's going to finish cleaning things up. In the meantime, I'll bring him the other half of the block and have him clean it up too. On the advice of William I'll also be contacting Dan Wesseman of FlywithSPA.com, William's recommended supplier for info on obtaining 12 new (to me) OEM matching long studs as the ones I have are too corroded to re-use.
To make things even better, Brenda tells me a fellow Corvair conversion builder called for me while I was at work and invited me to visit his shop near Barrie. He is building a Zenair 650 with a Corvair engine. It is almost complete at this point and offered to help answer any questions I might have along the way. I'll make contact with him tonight when I get home and maybe arrange a time to visit this weekend when I'm in the area for a family function.
What an AMAZING day Sunday was! Drove to Roseneath Ontario and met my new friend Paul.
Paul is a retired electrician who at one point in time had plans to build his own Corvair powered airplane. His plans got delayed for a number of reasons and he recently decided to sell his Corvair engine collection. Of course we could have talked for hours....
I don't have a complete list yet of what I obtained to post here, but I feel I got really lucky. Two complete core engines, several new parts and a custom work stand. I even picked up a billet aluminum prop hub and a bunch of technical manuals and drawings. More pictures to come when I get to inventory everything. It almost didn't fit in the truck (even the back seat was full):
A great day... sometimes things work out and I like to think somehow my mentor Barry had a hand in this.
Sunday was a combination of timing and a generous seller wanting to pay things forward. Something I will do as well.
Happy New Year everyone!
First day of 2016.... who can tell me where 2015 went?
2016 is going to be a watershed year for me. Among other things, I've decided and committed to myself that this will be the "year of the purge". Time to de-clutter, organize and continue to prepare for my build, both in the shop and around our home.
We've got so much stuff around the house that we never use, or had great plans for when we bought or obtained it. As I continue to tidy and organize the shop I realize how much space I've actually got to work with.
The purge is not going to be an overnight process, but it IS a new (or at least better) way of thinking.
For example, taking a break from the shop clean-up today, we reorganized the home entertainment / media centre. The jumble of wires gathered behind are now consolidated and labelled. The dust-monsters have been banished.
We got rid of the old non-functional computer speakers we were using as a sound-bar and they are heading to the library scrap electronics fundraiser. Substituted in it's place we put a component stereo system we weren't using elsewhere. More shelf space for books and pictures, and the TV sounds awesome!
The key is to be ruthless. I think most everything I'm not using can find a home elsewhere. Sell, recycle, up-cycle, donate, or trash in that order. Simple rules to live by.
Yup.... 2016 is going to be great!
The conversion manual I ordered is finally in my hands!
254 pages of information, knowledge and wisdom on converting a Chevrolet Corvair automobile engine into a reliable, powerful and economic to operate aircraft powerplant. Manual #801. I'm entering the arena!
Much to read and digest, but so far the instructions don't seem that complicated. I can do this!
I really like how the author William Wynne thinks and writes. Lots of motivational anecdotes and examples that speak to simplicity without compromising goals. Very cool!
Back to work on cleaning up the shop.... :)
Merry Christmas everyone!
Time until takeoff
Husband, father and 911 dispatcher. Long time pilot with a licence that burns a hole in my pocket where my student loan money used to be. First time aircraft builder. Looking to fly my own airplane.