A couple of more hours in the shop today. Work continues on the 701 wing rebuild.
Stripped off the last of the paint where the wing and nose skins will be replaced. A wipe down with acetone and it comes out real shiny! Next step will be to scuff the aluminium and paint it with primer in preparation for mating the new skins.
While I was letting the stripper soak in for the above step, I finally got up the nerve to clean and trim the nose skin where the damaged piece was cut away. Working from the outside, I wanted to make sure to cut not only straight but well away from the underlying nose rib. To make the task easier, I laid on a piece of painters tape outlining where I was going to cut:
The curve of the nose skin makes this difficult to use hand shears or metal snips. Bring on the power tools! Ron suggested using the air powered saw:
When it's running, the blade on the air saw moves faster than the eye can see. It's fine tooth blade made short and clean work of the skin. The last inch or so I did with metal snips to prevent accidentally cutting into the wing spar (that would be a unmitigated disaster!):
A productive couple of hours.
I've sent off a quote request to Zenair for a complete tail kit of my own, minus the rudder pieces I already have.
It's been a while since I had anything to post. Between my paid job, a weekend camping with my daughter's Scout Troop, horse shows and Thanksgiving hikes with the family time has flown by the last couple of weeks.
Found a day free in the schedule on Monday so popped into the shop for a bit. Ron and Donna had been away the previous week so Brenda and I were watching over the shop and property. I was pleasantly surprised when I arrived Monday to see that Donna was kinda enough to put my plans set into a binder for me:
Ron and I had a good chat about my build plans. Comparing the 750 plans to his 701 plans we realized that they shared even more DNA than either of us thought. Obviously we knew that the 750 is the evolution of the 701 design but we are both struck just how common the airfoil (wing shape) and internal structures are. It's easy to see where improvements were made over time and how Zenair has evolved in their kit manufacturing processes (introduction of CNC production of kit parts and CAD drawings). Ron's group of builders are scratch building their 701 planes and have made all the forming blocks for the 701 parts. In other words, rather than buy the kit pieces, they are making (read bending) everything themselves from bulk aluminum sheet and other stock. Time consuming? Yes. Cost savings? Huge (the cost of individual kit pieces from Zenair is in the manufacturing, not the actual materials).
Ron seems to think that his 701 forms are almost exactly the same as those needed for the 750, perhaps with a bit of tweaking. Comparing the plans seems to back up this theory too. So the question becomes one of time vs. money. Scratch building takes time but saves money. Enough money of course always saves time. I'm caught somewhere in the middle, but if I can save some money without too much investment of time there is opportunity there. What makes it better is all the work of the making the forms is already done.
I'm going to defer this decision for now and perhaps order a couple of wing ribs from Zenair. I'll compare the 750 kit pieces with Ron's 701 forms and see just how close they are or what modifications need to be made. From there the decision should be easier. If it turns out the forms aren't appropriate, at least I'm a couple of pieces closer to the end....Ha!
So, onto Monday's task - start stripping the paint off the wing skins anywhere new skins will be overlapping. This ensures good strong joints and provides a clean aluminum surface for anti-corrosion primer.
First, apply the chemical stripper. I'm thankful to have a workshop space that isn't in the basement of my house - this stuff is strong!
After letting it sit for a while, a plastic scraper works fantastic to remove the layers of paint:
I didn't take any final pictures yet as I still have some clean-up to do with acetone and Scotchbrite pad. It's not pleasant work, but I learned the work involved if I change my mind about what colour paint I want for my airplane! While I waited on the stripper to work, I also reworked that rear channel I made that had cracks developing at the corners..... always keep busy.
I'm away next week on a work assignment (near the Zenair Canada factory!) so shop time will be limited again. I wonder if I can order those ribs and have them in time to pick up while I'm in the area? Hmm....
Friday finally got here and I departed home for my road trip to "parts south" at 1130am.
First stop, my long time friend Lynn's place just outisde Barrie. Lynn and I grew up in the same hometown of Holland Landing and her late father Wally owned the local airport. For several years Lynn was heavily involved with ultralight aircraft, as a builder, pilot and instructor. Now heading in a different direction in life, she contacted me with a list of items from sale from her collection.
As I arrived in her driveway, I was very pleasantly surprised to see that one of my best friends Mike (also from Holland Landing) was also there. It was just like old times - what a fantastic chance to catch up a bit. None of us has aged by the way ;)
Lynn had collected up a bunch of stuff for me and made a sales pitch I couldn't refuse. More on this in a bit.
Next stop, my parent's place to pick up Dad and head to Kitchener to see Scott about the 750 rudder he has for sale. I like taking Dad on these jaunts when possible. It's great to catch up and of course talk airplanes - it's certainly something in the DNA I got from him!
After a dinner in Guelph with Dad, we made our way to Scott's place in Kitchener. The deal for the rudder we agreed to got even sweeter when Scott included a box of Cleco fasteners, Cleco pliers and two heavy paper bags of A4 and A5 rivets - all for $100 cash! I didn't dicker or give him a chance to change his mind. START THE CAR!!
We wound our way back to Dad and Moms during Friday evening rush hour and seemed to hit every red light. Times like this remind me how much I enjoy living in northern Ontario. I decided to grab a nap for a couple of hours, but by 415am this morning, I was back on the road home (there are other things I have to get done before going back to work tomorrow!)
Once I got home and had some breakfast, I began the inventory process.... in a word, wow!
Here is a group photo of the items I obtained from Lynn and Scott. Top to bottom, left to right: A handful of the several reference books, bags of Cleco fasteners, over a thousand rivets (paper bags), Cleco pliers, drill bits "The Claw" aircraft tiedown kit and a "One Touch Tach" tool used for confirming prop RPM.
Amazing stuff for my project. In fairness to Lynn, I won't disclose what I paid for her portion of this stuff, but suffice to say, it pays to stay in touch with friends!
The big item of the trip however is the 750 rudder. Scott had attended a Zenair factory sponsored rudder workshop with the intent of getting a head-start on his 750 build, but as is often the case, life got in the way and he decided to part with his barely touched project. This rudder is already mostly built, including corrosion protection. Fortunately one side only has some temporary rivets on the skin that can be drilled out so I can confirm everything is good inside and run the wires for a navigation light. For $100 and the fact it was built in a supervised factory workshop I can drill a few rivets out to confirm. Unassembled rudder kits are more than $500 from the factory and there is at least $100 in hardware that he threw in.
Can't wait to show Ron!
But right now, the lawn needs to be cut.... again.
Snuck over to the shop for a couple of hours Monday morning. I'm trying to squeeze in time when I can and a few hours in the morning before I head to bed for my afternoon pre-nightshift nap works perfectly.
Work continues on the 701 wing repair/rebuild. I managed to fabricate my first replacement piece, a rear wing channel. It took some time to figure out how to use the sheet metal bending brake, but I got it done. Here you can see the original bent and mangled one on the right and my new one on the left. The previous builder for some reason made his channel with a thinner gauge of material than what the plans call for. I'm all for saving weight and money, but this is a critical structural component, not something I would consider worth skimping on:
Next was removal of the damaged nose skin. As part of the repair/rebuild, Ron is planning on extending the wing by a couple of feet. We'll cut out the damage, fabricate a tip extension to the main wing spar and add a rib where required. A new nose skin and upper/lower wing skins and will be cut and fastened to the originals. Of course, this means drilling out more rivets. I suspect there will be times this will come in handy when I make mistakes on my own build!
This picture shows the extent of damage. What do you think..... is this creased too far to be "popped out"?
I drilled out the rivets on the closest good rib to allow some flexibility when cutting the bad nose skin. We'll trim it cleanly back to the rib to enable a clean joint with the new extended skin. These empty holes will become part of the stronger joint as a result.
As always, I'm keeping my eyes open for good deals on things I need for my project. Surfing the classifieds section of the Ultralight Pilots Assocication website, I came across an individual selling a complete rudder section for a CH750 for an amazing price that was too good to be true! A quick game of phone tag and the seller and I agreed to meet on Friday this week.
On the road again..... can't wait to get on the road again.....
After a couple of weeks pouring over my new plans and discussing them with my friend Ron, tonight I begin the never ending trail of paperwork that needs to be filed with Transport Canada.
It all starts with a CO1B "Letter of Intent" that gets submitted to the MDRA inspection agency. MDRA stands for Minister's Delegates - Recreational Aviation. Essentially the federal transportation Ministry decided a number of years ago that they didn't have the resources (or knowledge) to efficiently manage the inspection/inspector process for homebuilt recreational aircraft so they created another level of bureaucracy (i.e. fees) for those who wish to build and fly their own aircraft. The one good thing about this government mess is that MDRA inspectors come from the homebuilt community and should understand what most builders are attempting to do.
So, first form done and submitted (don't forget to include the $80+tax filing fee, ouch). Now to wait and get confirmation that MDRA has started a "file" on my project..... then I can start my build.
Yesterday, I called Zenair HQ to inquire if my plans had been shipped yet. I spoke with Kaitlyn who confirmed my package left their facility via U.S.Postal Service Air Mail on Friday afternoon.
Today, using the tracking number she provided me, I logged into the USPS web-portal and discovered that as of Monday morning my package was somewhere in the bowels of the USPS International Service Center in Chicago. Further reading reveals the ISC where all outbound mail from the U.S. goes to be sorted for distribution. I also read that it can be a bit of a black hole and there are many reports of stuff going missing, never to be seen again.
Thankfully when I checked a couple of hours later and my package was showing as of Wednesday morning as being in Canada Customs. I'm normally more patient than this, but Canada Post and their postal workers union are deep into a nasty labour dispute with both sides threatening strike/lock-out action by midnight tonight! At this point I hoping my plans wouldn't end up stuck on some conveyor belt or parked truck.
Knowing that web-portals are sometimes slow to update, I took a chance and called my local Post Office (love small towns). The lady there confirmed for me that I indeed had a package awaiting pick-up!
Brenda was kind enough to drop by and pick it up for me (I was stuck at work). When I got home, it was waiting for me. To be honest, I kinda thought it would be a bigger box, but happy nonetheless it has arrived safe!
Opening the box explained a lot. The plans are curled a bit on one end to fit a standard shipping box:
A fully numbered and complete set of plan drawings and folder with builder resource information including a CD of assembly photos. Really nice stuff.
Who's a happy guy?
Got a confirmation e-mail today that my Zenair 750 STOL plans are on their way from the Zenair factory in Mexico, Missouri. Despite being a company founded in Canada, all plans come from the U.S. office of Zenair as they are numbered and serialised for each builder (makes sense really, the U.S. is a huge market for homebuilts.) It's also great way for the designer to keep track of customers and provide support.
With some luck, I should have them in my hands in 5 to 7 business days!
In my previous post "Time to get back at it" I mentioned spending a day in July at the Zenair Open Hanger day in Midland, where I met fellow Corvair engine builders John from nearby Angus and Jeff Moores of Newfoundland.
Here are a couple more pictures from that day that Jeff's wife was kind enough to send me.
Hoping to get back into the shop this week. More rivets to drill on the salvaged wing. Learn I will..... learn :)
First off, I ordered my plans set today! Hopefully it won't take long to be shipped from Zenair. Once I have them, I'll have my very own serial number and I can start going down the road of endless inspection paperwork that needs to be on file with Transport Canada. I'm trying to decide if I want to reserve a good registration (call letters) or wait and see what they assign..... but that's a bit premature.... ha!
Four more hours in the shop today. Continued to open up the salvaged 701 wing. Wasn't too surprised to find damaged structure inside. This is the top of the wing at the root where it attaches to the fuselage. It likely got twisted back from the impact out on the tip of the wing. Lots of rash damage, probably from improper handling after the crash.
Flipped the wing over and with some drill effort, off comes the wing root fairing, fuel cell inspection cover and lower wing skin. Whomever built this wing wasn't much of a craftsman (or craftsperson). Lots of rivets where they shouldn't be, and lots of rivets missing from where they should be. We also discovered the rear spar channel is way under gauge from what the plans call for. Seems like someone decided to take a shortcut.
Next step was to drill out the rivets holding in the incorrect rear channel:
It came out easy, but it too has holes in all the wrong places.
Easy to fix/replace, but after seeing this, we are truly wondering what else we are going to find.
Next up, straighten the inboard main wing rib (on the left in the above picture). It will require another strip of aluminium (called a doubler) to reinforce the damaged area after we straighten it.
I just two afternoon sessions, I've learned a ton thanks to Ron but I've got a ton more to learn yet!
Had a real great afternoon today speaking with and working in the shop of my new friend Ron. As I've stated before in my blog, the prime motivator of building my own airplane is about learning.
Ron is a long time builder and re-builder of aircraft, both certified and homebuilts. He has a very deep knowledge of all things in recreational aviation and most importantly wants to teach me some of what he knows.
Ron's current projects include rebuilding a Cessna 170, a short wing Piper and several Zenair projects. His thinking is to have me assist his group of builders repair a Zenair 701 as a very first step to learning metal aircraft construction. Perfect! What a fantastic way to get an introduction to building skills.
He gave me a quick tour of his workshop and we immediately went to work on removing the skins off a salvaged Zenair 701 wing that was badly damaged by a previous owner. This wing is being rebuilt.
We started by assessing the wing to determine the best course of action. We discussed what was salvageable as is, what could be patched and what would need to be cut away completely. As you can see in this picture, the damage is substantial.
After making some marks on the wing of what needed to be removed and a quick demonstration of the procedure required, I was drilling out the rivets. As you can see, there are a ton of them:
We also removed the lower wing skin closest to the wing root that was crinkled really badly. Again, a ton of rivets to drill out:
I wish I took more pictures, but I was having too much fun drilling rivets. Obviously today was just a tiny taste of what's to come for learning and building, but I'm hooked!
As we worked, Ron and I talked at length about my plans for building a Zenair 750 STOL. I explained my plans to put a Corvair engine in it and he was very interested in the combination.
Use of Ron's shop and taping into his experience building Zenair aircraft definitely confirms for me that this 750 STOL airplane is a do-able project that I can accomplish, and that by making some of the parts myself from raw materials (called "scratch building", as in "from scratch") I have the opportunity to save a bunch of time and money.
So after some weeks of debate, tomorrow I'm sending in my order to Zenair for a complete set of builders plans for a 750 STOL aircraft. Once I have them in hand, Ron and I are going to sit down and discuss a build plan.
I haven't posted anything to the blog because I've really not made any progress in the past couple of weeks, other than research stuff. Summertime is difficult.... hot and muggy and plenty of other family plans and activities to occupy my time.
Had a few minutes today though, so I thought I'd get out the core crankshaft I have safely stored in inventory and have a better look at it. One of the first items I'll be sending away for prep work, but it needs to be measured to see if it still meets factory specs.
This is the crank I inherited from the inventory I purchased in February. The previous owner had already completed some of the work to make it airworthy and it's in great shape:
The recommended prep work includes magnaflux testing for internal damage, straitening if required, heat treating for improved strength (ion nitriding) and grinding the piston rod journals to improve the fillet radiuses. Larger journal radii help prevent stress riser cranks from forming, which has led to broken crankshafts in the past. The process is quite common in certified aircraft engine cranks, so it's worth doing here.
One of the other processes that normally gets completed is to drill and tapping the centre of the end of the crank for a propeller hub safety shaft. Because the previous owner was working from the official plans, he had already completed this process with his machinist:
I opened my Corvair shop manual, and found the engine spec reference page. It contains all the measurements for the major engine components:
Using my digital caliper, I tried to measure as best I could the crankshaft main journals and connecting rod journals to see how close they are to factory. I really should be using a micrometer for this, but my calipers should at least let me know it's in the ballpark.
The manual says the connecting rod journals (they call them crankpin journals) calls for a diameter from 1.7999 inches to 1.800 inches. To make it easier to measure, I set and friction-lock my caliper to 1.7990 before placing it on the journal. This is slightly undersize, but as close to 1.7999 I can get. This way if the caliper slides over the journal without resistance, I know that it is below tolerance and no good for grinding. Anything larger than that leaves that much more room for the machining (good):
With my lovely assistant Brenda taking an action shot with the camera, I carefully measure each of the bearings:
It's real hard to get a good picture, but the caliper won't span the largest diameter of the journal, so we can deduce that they and the main journals (using the same measuring technique) are clearly above the minimum spec and can be used for conversion. I know it isn't a perfect measurement and my caliper may not be as accurate as a micrometer, but I think I'm in the ballpark at least.
I'm going to see if I can borrow a good micrometer from someone, or maybe buy one for myself to confirm this. Once I'm sure, off to Florida the crank will go for prep.
Next Wednesday I'm having my first shop lesson with Ron, another Zenair builder. He's rebuilding a Zenair 701 and has offered to let me help. What a great opportunity to learn and prep for my build.
More to come.....
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.