Re: #Northernfox Build
Well, so much for updates on my project. More than a year since my last post here. As much as I hoped to chronical my build (as I love reading all the build threads myself) there just wasn't enough time in my day to do so. Especially with COVID. There was a very long stretch of not doing anything build related. Two kids under 5 at home full time, a full time job and trying to build...you can image I'm sure.
That said, lets see if I can provide some updates. I'm DONE! Well, 99% done. Waiting for inspection next month and a few little things to button up before then.
Here's how things went over the last year... from what I can remember. There was way more fabric to finish than I realized. All the little things that take 90% of the time. Using oratex I wanted to do as much as possible without paint. So my under wing and tail registration was all hand cut, masked and applied with oratex. That was a lot of work. Edge tapes on the tail were also very stressful and took multiple tries on the smallest radii. I actually hand cut a tape with a curve already in it - which worked out great.
The dash. As posted in the dash thread it turned out amazing. There was a lot of thought put into it - probably more than anything else. I wanted it minimal with only the most used items having physical toggle switches. Best part is I can easily modify those with the VPX if I find I don't like the current combination. I've sat in there for hours playing with it and setting up the g3x - I really like it.
Upholstery. I didn't have anything and figured I could do it all from scratch. That was way more work than expected as usual. I decided on a two tone interior to match the exterior. Also decided to use a high grade marine fabric. For the foam I went with a 2" thick high density cushion foam derived from soy bean. Materials alone cost me about $650 cdn. Cutting the foam wasn't too bad - but I did use some cheap test foam I had laying around to test out a few ways to cut for the control stick. I added an extra thickness to the bottom near the edge of about 1/4" to hopefully reduce any strain. One of the things I really wanted to do was be able to make the seat pan look great even with the cushions out. That's where things got difficult and I had to get creative. The fabric only stretched in one direction and there was no way I was going to one piece the entire pan. In the end I used panels with nice stitched edges to cover the entire seat pan. On the bottom with the help of Velcro the panel covers the seat box but still provides easy access. In the end it turned out great and I'm very happy with it. I do have to fix a few spots where the velcro wasn't correctly glued to the pan and it pealing off. No big deal though. The dash was covered with the same material (twice) as the first time I damaged it when installing into the plane. The door hydraulic piston tabs cut right into the dash - which is going to make it very precarious to remove if I have to. I also made some custom seat belt covers which really set it all off perfectly. The control stick covers were done with $20 shifter covers I found on amazon. They worked out ok.
Being a model 6, the turtle deck provided was not a single piece of lexan - so I decided to make my own. I purchased a nice dark smoke lexan and took measurements from the sheet metal deck I had. Using a friends 5 ton bender I cold bent the lexan and it turned out perfect. Now the next step to the custom deck was a special keyhole cutout made with acrylic to accommodate the BRS chute exit point. That turned out great and I made a custom ledge so that it sits flat with the surface and is held down with small plastic car clips. Had to make the insert twice. The acrylic shattered the first attempt.... exactly what it's suppose to do in this situation upon rocket exit. So I'm confident that won't be an issue.
Now of coarse there were all kinds of other little things to deal with... gas line completion and testing... only had a small drip leak in my sight tube on one side - and countless other things - oh, like the doors and designing a new custom handle/lock system.
With everything but a small list of chores left it was time to fill all the fluids and start the engine. Christmas eve was the big day. It was the first time taking the plane outside of the shop with wings on. It was a great feeling. (although a bit cold at -8C). The first thing I did notice however was that in the cold the oratex showed spots where I obviously didn't shrink evenly and I will have to go over again. (once back inside it the warm it was taught again - but I still have to go over it).
First thing on the list was fuel flow test. I opted for the 20 degree test as it was hard to find any other recommendation. With a friend helping we started the test - each pump individually and then together. Somethings a bit odd at this point. In each test we were seeing 4L/min - I'm suspecting that the filter is being bypassed either because it's blocked for some reason or backwards. I've not dug into it. Fuel pressure is fine when checked.
We went ahead with the engine start shortly after. First crank it roared to life. Seemed far too easy - but I wasn't complaining. Ran it for about 4 min as we started to notice a small ticking sound. Pulled the valve covers to find cylinder 3 intake and cylinder 2 exhaust valves were not holding and the rockers could easily be pushed down with one finger. After a quick chat with Rotax and finding out there was an SI last month in regards to this - we were told to run it up to 3x10min and bring up the rpms. After doing so and re-checking everything all cylinders were good and the tick was gone. Back inside we assessed everything. One small drip from the oil return line on the exhaust - tighten that up. The pilot side break line had a leak under the seat where it passes through the fabric. Worst though is there is a 2" crack in the windshield near the wing attach. Have to stop drill that and hopefully repair.
Next up was the W&B. I was guessing around 880 given I have a 35lb brs system. Wow, I was wrong. Clocked in at 907lbs. 68lbs on the tail. Things obviously add up faster than expected. 26" airstreaks, t3 tail with large wheel, brs. I also assume the made from scratch wings are heaver than factory built option too. Anyway, it is what it is. Now, this ended up putting me at a CG of 10.4". Further back than I was hoping, but not unexpected given the BRS in the baggage area.
So, next up is the chores list and final inspection mid january. Can't believe I'm here.
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