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Two Projects For My Fisher Biplane

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FanMan

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#1
Here are two things I made for my Fisher FP-404 biplane. The first is an oil separator... the 2 cylinder opposed engine has such large variations in crankcase pressure that it pushes a lot of oil out the breather, which ends up on the underside of the fuselage if it's not captured. When I bought the plane, it had a "puke bottle" on the breather, but too much vapor still found its way outside; I had to wipe it down after every flight.

I was limited by the lack of a lathe, but where there's a will there's a way. The tube (2" OD aluminum) was easy, just face it off in the mill. The endcaps fit over the tube with an o-ring in the groove, which I made with a holesaw. I then roughed out the outercircle with a bandsaw, chucked it up on a bolt in a collet in the mill, and turned the OD with a cutter in the mill vise. The fittings are aluminum, too, I cut the pipe threads short, tapped the pipe threads in the tube, and use JB Weld epoxy to secure them (welding would have been better, but I have no way to weld aluminum).

Oil_Separator_294.jpg

Oil_Separator_132.jpg

The lower fitting connects to the engine breather, which has a check valve so gases only go out of the engine. There's a copper "chore boy" scouring pad in the lower part, coalesces the oil out of the vapors so it drips down. Above the divider, the upper fitting vents clean air overboard. At the very bottom, a much smaller fitting is the outlet for the coalesced liquid oil, which returns to the engine via the small line, with another check valve letting the liquid in. It works quite well, and has significantly reduced my oil consumption.

Oil_Separator_273.jpg

The second project was a new tailwheel. The plane's original tailwheel was serviceable but ugly... it looked like (and no doubt was) an ordinary caster wheel that somebody welded arms to and drilled a bunch of holes in attempting to make it lighter.

old_tailwheel_DSC00017_reduced.JPG

I looked at a few commercially made wheels, but everything was overkill, overpriced, or out of stock, so I made my own from some aluminum angle, a 4" scooter wheel, and a Delrin pivot block and a steel bushing for the pivot. Looks better, works better, and will be featured in an article in the March 2017 issue of Kitplanes magazine (there's also an article about the 6 month process of restoring the plane to flying status in the February issue). They want an article on the separator, too, but I didn't take any good photos while making so I'd have to make another one to get the photos... they'll pay, so we'll see.

IMG_20150309_185447_283_cropped.jpg
 

wrat

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#2
the 2 cylinder opposed engine has such large variations in crankcase pressure that it pushes a lot of oil out the breather, which ends up on the underside of the fuselage if it's not captured.
Don't think too poorly of the engine. That's the price paid for air-cooled, 4 stroke, aluminum engines. It just is. Some are built like Swiss watches and they still puke oil.

It's not from anything being wrong. When they're cold, they're loose; when they're hot, they're tight. And it seems like there's no time in between when everything, like seals, valves, and rings, are just right. There's always something not playing well at every temp.

Nice breather.


I looked at a few commercially made wheels, but everything was overkill, overpriced, or out of stock, so I made my own from some aluminum angle, a 4" scooter wheel, and a Delrin pivot block and a steel bushing for the pivot. Looks better, works better, and will be featured in an article in the March 2017 issue of Kitplanes magazine (there's also an article about the 6 month process of restoring the plane to flying status in the February issue). They want an article on the separator, too, but I didn't take any good photos while making so I'd have to make another one to get the photos... they'll pay, so we'll see.
Hope they pay plenty because that is the nicest tailwheel I've seen, homemade or otherwise, in a long time! That's really sweet.

It's steerable and simple. No welds to crack under high vibration loading, either. I've never seen the draw of the big, dumb, heavy tailwheels that are out there for $500. Keep it simple! Yours is great!

Wrat
 

wrat

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#3
Uhm... i probably ought notta say this, but I might be keen to make a minor change on the tailwheel.

The attachment hardware is definitely not AN grade. In the photo, it looks like ordinary galvanized screws, although maybe not. Someone is gonna get their knickers in a knot over that. I won't, because I know the loads are not that big on the tail of a Fisher 404.

However, it can't be seen by the photo, but I'm hoping the attach bolts are thru-bolts ending with a washer and nylock nut on the far side. It looks like it could be based on position of screws and pivot bolt. But if not, there are threads into the center block and quite possibly threads in a load bearing role. This is generally considered to not be airworthy. However, on non-flight-critical hardware, like a tailwheel, and especially Experimental, I can't be certain.

Usually, people like magazine editors overlook these kinds of things, but their letters columns often fill right up on the subject. Obviously, it'll work fine as-is, no matter what, but thought I'd point out there might be some 'comments' concerning the configuration were that to be the case. And you know how people pounce on galvanized stuff.

Still a dynamite tailwheel, though. I really like the double-angle, center block setup. That's a great solution to a nagging problem. Consider this idea stolen and soon to be flying on a plane near me.

Wrat
 

FanMan

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#4
Don't think too poorly of the engine. That's the price paid for air-cooled, 4 stroke, aluminum engines. It just is. Some are built like Swiss watches and they still puke oil.

It's not from anything being wrong...
Nope, nothing wrong at all, just the way a two cylinder opposed engine is. It's really a nice running engine, if a bit small for the plane.
 

FanMan

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#5
Uhm... i probably ought notta say this, but I might be keen to make a minor change on the tailwheel.

The attachment hardware is definitely not AN grade. In the photo, it looks like ordinary galvanized screws, although maybe not. Someone is gonna get their knickers in a knot over that. I won't, because I know the loads are not that big on the tail of a Fisher 404.

However, it can't be seen by the photo, but I'm hoping the attach bolts are thru-bolts ending with a washer and nylock nut on the far side. It looks like it could be based on position of screws and pivot bolt. But if not, there are threads into the center block and quite possibly threads in a load bearing role. This is generally considered to not be airworthy. However, on non-flight-critical hardware, like a tailwheel, and especially Experimental, I can't be certain.
The fasteners holding it together are two piece steel binding posts (one male threaded piece and one female threaded piece; heads on each side, threaded into each other). Plenty strong... loads are very low; the tail is very light, and as you say it isn't flight critical. On an experimental, pretty much anything is allowed.
 

stupoty

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#6
I'm not an aero expert but that tail wheel made me laugh hard :)

Like your replacement. Looks much more plane'ish

Stuart
 

wrat

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#7
On an experimental, pretty much anything is allowed.
Oh, you're quite right. It's probably allowed.
But when the article comes out -- they're so lucky to have your project, btw -- many will comment. Hopefully, they'll edit out the pedantic nasty ones. But some mags and editors (one or two come to mind) have been known to use everything they can to create controversy and short term interest.
Wouldn't want you unprepared for being in the vortex of such a fray.
 
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