[79FT]: Building Things
|On:||Mar 11, 2021|
|In:||[Chickenhouse Charger] Electrical Rebuild|
|Tags:||6781G, MA5 Charger, paint, fabric, polyfiber|
The end in sight; fixing up all the chipping off paint was one of the remaining little things to fix on the Charger before she could take back to the air.
Regardless of history, I knew that she was painted with Polyfiber and Polytone (MEK test proved that).
Back in 2019, when I just got her, this was one of the things I have discussed with a couple of fabric folks, and a few folks from Polyfiber during Oshkosh. With variations, this approach is what seems to be the common theme unless one wants to do a drastic restore - either rejuvenate, or recover.
But first, she needed a bath after almost 2 years in the hangar :).
One wing donw, one to go
What a difference, eh?
I had a bunch of areas like this:
Chips and cracks
Large and small, mostly in the prop wash area where things drum the most.
The approach is not much to talk about. I called it Cleetus-style: a perfect redneck fix for chips in fabric that's purely functional and ugly as hell, and even has the perfect color of duct-tape.
First, I would chip out all the flaking paint, while not being too aggressive: one of the guys I talked to said that if you get to excited with chipping and peeling, you can peel the whole plane if the coatings are starting to lift.
Then, I would take a rag wet with MEK, and work those edges of remaining paint to melt and blend them in, creating somewhat of a "slope"...
And then, I would layer silver (Polyspray) on top of pink (Polybrush) until it was just the perfect level of ugly, and I would feel that I have enough Polyspray to prevent UV attacking the fabric... Doing a 60 watt bulb test to see if any light's coming thru was not really adequately possible for these cracks really, and I opted for layering silver thick enough to be sure I'll have a sufficient amount.
Perfect ugliness! "You're giving your plane leprosy", remarked my old buddy Jimmy C., accidentally bumping into me in my hangar when he was at the airport. "Yep", I said. Indeed.
Interestingly enough, roughly at the same time someone with a similar problem was soliciting advice on the Biplane Forum. I offered making him a short video about my process, and it turned out to be a much better illustration than what I got above.
Forget all that stuff about thrust and drag, lift and gravity, an airplane flies because of money.
...and 1/2 of May
|On:||May 14, 2019|
|In:||[Chickenhouse Charger] 2019 Annual|
|Tags:||6781G, MA5 Charger, Annual, Rotec TBI, baffles, prop, fabric|
Well, as usual, I got too focused on the plane and the mess I got myself into; and didn't log things as they went...
I will split the notes in multiple posts; by theme / subject. Just general notes here.
We got together with John, my IA, and continued working on the plane early April.
We pulled the prop, so that I will have access to baffles (I wanted to redo them).
John re-riveted the air takeoff flange back to the front ramp.
Meanwhile, I started disassembling the fuel system to get to the screens, including the oil sump screen, and clean them.
TBI intake airflow straightener
Okay, stop right there. See that fuel inlet, right above the air intake? See the little smudge of dope around the inlet fitting? Yep. Teflon dope. Rotec explicitly tells you not to put ANYTHING on there - there's a copper crush gasket behind that fitting.
TBI crush gasket
See all that dope above? Okay, that thread on the TBI is a female thread. Dope will be all in it, and guess what will happen when I screw the fitting back in? Yep. It'll go into the TBI fuel galleys. Right to where that spray bar is with tiny little holes in it. Not Good (c).
TBI holes plugged
I noticed evidence of possible intake leaks, so without "burping" the engine, decided to pull the intakes and replace the gaskets. This is my karma. I did that on the Cheetah just a year ago, and scraping remnants of one of those gaskets and re-chasing the threads took me about 10 hours; maybe more.
Also: interesting note: she has intake tube clamps on studs and not bolts like every other Lycoming I've seen. Old, narrow-deck cylinders :).
When we pulled it, bolts were in the thru holes on the wooden prop really tight.
Pulling the prop
She has the prop made by Frank Johnson of Performance Propellers fame, and after contacting him, he just suggested to re-drill the holes and re-coat them inside with something.
Well, I got me a 29/64 (1/64 oversize) reamer, and went to town.
But first, I needed a rack.
My prop rack
Built with a 1/2" pipe, some foam, pipe brackets, screws, 2x6s screwed to the table, and my 3/8" drive extension rod. You get the idea :). Redneck engineering galore.
Prop on the rack
This whole thing was happening over a few days by the way; and when I finally got my reamer and had time to deal with it, the holes.. extended. Wood moves!
Hey, we had much rain then, and prop "swelled" a bit methinks.
But I still decided to fill the holes as much as I could.
Even got me some nice scales for mixing System Three ClearCoat.
A filled hole
Fabric on this plane is old. Flyable from what I am being told by experts, but old. Cracking, peeling paint.
Original logs say that she was covered in Polyfiber. But the current finish looks more like Imron and the company - "flexible" automotive poly. It's cracking and peeling around areas of high wear (prop wash, etc).
Sad, sad fabric
John (my IA) wanted to take a Maule fabric tester to it; but I didn't want holes in my wings.
I discussed this with a few guys that worked with fabric their whole lives, and we came to a consensus that for now this is fine. Will just fill with silver, and keep on flying. Incidentally, that's what Glenn has been doing, too.
I worked on baffles a bit, but then, everything went downhill. We'll talk about baffles in the next post. And the downhill part, afterwards :).
Good judgment comes from experience and experience comes from bad judgment.
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This website only shows how I did things in my various projects. These pages are for information and personal entertainment only and not to be construed as the only way, or even the perceived correct way of doing things. You are responsible for your own safety and techniques.