Posted Saturday, October 27, 2007 @ 01:54 AM  

By now most of you will have read about my wheel-up landing. If you have, just skip to the end and the photos.

For newcomers:
I was doing aerobatics while tired and jet-lagged, up against a deadline, overdid it, felt queasy, got low, decided to land, must have decided to leave the wheel until a little later because I was low, noticed the shallow glide on final and the need to sideslip (forward slip) but DIDN’T realize that was because I had no wheel drag. No horn when the throttle was closed and the airbrakes were out, so I relaxed. I even checked the little locking lever was in place – it was, but the wheel was locked up. Bang! No propeller.

It tuned out, of course, that a wire to the horn and light from the wheel and spoiler microswitches had snapped off. When I went to fix it, another did so in my hand. Right where they go into the test button. Then the other wires all snapped off!

I later discovered that other Fournier owners had been experiencing similar problems with their forty year-old wiring. I also learned the power source for the test button is quite separate from that through the spoiler, throttle and wheel microswitches, so all it tests is the bulb and the horn, not circuit continuity or the microswitches.

Now my lever is painted green on the side I can only see when it’s down, and red with yellow stripes on the side visible when it’s up. I don’t expect that to stop me from doing it again, though.

Good luck to you all.

Bob

[Edit by Bob Grimstead on Thursday, February 4, 2010 @ 02:35 AM]

Posted Monday, November 12, 2007 @ 03:20 PM  

I feel more confident in the 4 partly because XST has a window in the wheel-well cover. I haven´t seen that in cockpit pictures on other RF 4´s. When the wheel is down in the air you can see straight below you; the fence, the neighbours horses and various other items directly underneath that you otherwise would have been blissfully unaware of. Moving things draws your eye, so I automatically glance at the moving ground through the window after I put the gear down. It´s reassuring to actually SEE that the gear is down, but I have made a habit of checking that locking lever too.

The window is also useful to check the ground you´re taxiing on and it greatly facilitates alignment on the centerline when you taxi in tight spots. Don´t tell anyone, but I generally taxi into the hangar and being able to follow the white centerline has prevented banging the wingtips in the hangar doors- so far....

I mostly fly from grass strips. Another advantage of the window is that if the strip is damp you all know that lengthen the take off run A LOT. Sometimes this can be hard to judge, maybe part of the strip has been in shadow, are water bogged or wet for other reasons. If you keep the wheel-window reasonably clean you can see the water drops sprayed from the wheel so you are more prepared to abort your take-off run if you are not airborne were you thought you would be.

I don´t know who in the UK made the modification, but as far as I can see it´s an easy one- just some polycarbonate, a frame and 4 screws. But maybe you all have already installed a Palmcomputer artificial horizon/3Dterrain/highway-in-the-sky contraption in that space on the wheelcover?

Take 5(b) just 4 fun/ Jörgen, SE-UDI, SE-XST

Posted Monday, May 19, 2008 @ 10:28 PM  

Your slip indicators look interesting, have you got a source for them?

BR

Posted Saturday, May 24, 2008 @ 01:33 PM  

We've got off topic again.

It's easiest to mark the forward face of your wheel lever with alternate stripes of red and yellow PVC ('insulating') tape, and the rear face with a long strip of green tape.

Photos follow when possible.

Posted Thursday, February 4, 2010 @ 00:44 AM  

You may or may not know that, however much you are in denial, virtually every Fournier pilot subscribing to this forum (and most of the others, too) has either landed wheel-up or (more common) had a wheel collapse.

There are a few ways to ensure this does not happen to you, and most of them are quick and simple.
Take it from me, who has done it, that trying to fix the problem afterwards is most definitely NOT quick and simple.

The first safeguard takes seconds (well, OK, maybe five minutes) and costs cents -- OK, maybe two dollars.

Get a piece of flat plastic - an old credit card maybe, or I use a piece cut from the side of an emptied plastic oil bottle.
Cut it to size.
Cover it with stripes of red and orange PVC tape ('insulating' tape).
Fix it to the vertical rib forward of your wheel lever with double-sided adhesive tape or a 'sticky fixer', so that when your wheel is down, your lever obscures the card.
I also paint or tape the lever green.

This is a good visual cue, which will tell you at a glance on final approach that your lever in not in the correct position.

Posted Thursday, February 4, 2010 @ 02:26 AM  

René Fournier’s retracting wheel is a magnificent design, with effectively only two moving parts and three operating levers, but it does suffer from failures (both human and mechanical) so I’ll try to run through them. I believe there are five main failure modes, although pilots being pilots, I am sure others will appear with time.

1) If the wheel is not properly locked up after take-off, it can smack down under G, causing a lot of damage.

2) If you forget to lower the wheel, you can do a lot of damage.

3) If you lower the wheel but do not thoroughly check that it is properly locked into position, it will collapse on landing.

4) Cracks in the casting can cause a collapse.

5) Pushing too hard, too often on the main lever (lever 1) has caused fatigue cracking in the weld at the bottom.

Here is a photo of the whole retractable wheel mechanism.
As seen here, this is actually extended a little past the properly locked-down position, illustrating the first problem mentioned above.
This is how the mechanism can end up after an inadvertent in-flight extension.

There are three castings.
Let’s call them Casting A, the fixed portion which is bolted by seven bolts though the fuselage main bulkhead.

Casting B is the long piece, which goes up and down on retraction & extension.
This is where the cracks happen.

Casting C is the U-shaped yoke into which the wheel fits.

There are three operating components in the cockpit.
Let's call them lever 1. This is the big, long lever with casting B on the bottom end of it, the handle of which I paint green on the rear face and striped red & yellow on the forward face.
As the wheel retracts, this moves from a vertical position beside your right knee to lie flat beside your seat.
I call it the main lever.

Lever 2 is the smaller, near vertical lever with a knob on it.
In this photo, the knob is painted white.
I call it the locking lever.

Lever 3 is the little, near horizontal white one with a trigger on the forward end of it.
This locks lever 2 in place.
I call it the safety latch.

Lever 2 operates a pair of arms with lugs on the end.
These lugs fit into the up- or down-lock cut-outs in casting B.
They are pulled into place by strong, tension, coiled springs.

If anybody can annotate this photo with the appropriate numbers and letters, I would be very grateful.

Yours, Bob

Posted Monday, May 3, 2010 @ 10:57 AM  

The thing that saved me was that I was coming around on to final full spoilers too high and not going down all that fast with a 20mph left front quarter x-wind.

At about 50 ft I retracted the spoilers and hit the throttle to go around and as soon as I took a quick glance to reach for the throttle I saw my LED gear up flasher and realized my gear was still up.....whew!

The first clue should have been the warning horn which I had defeated with the switch since I was puttering around at idle and could not stand to hear the horn any longer as I was coming down from 7,000 MSL.

The second clue should have been the insufficient sink rate with just the spoilers. Gear down adds just the right amount of extra drag that I have gotten used to.

In pondering my actions and inaction I think an easy fix would be to affix a prelanding checklist to the wheel well cover with a clear window into the wheel well next to the gear down item...."If theres light its right"

But in considering my habbits in the downwind, spoilers are always actuated if for no other reason than to see that they are functional.

I think another microswitch for the spoiler handle would be fairly easy to add, that will sound the horn, bypassing the horn defeat switch.

Posted Tuesday, May 4, 2010 @ 03:01 AM  

Thank you so much for sharing your Fournier experiences, both good and bad.

The day I landed wheel-up, I had to sideslip all down final and my brain was thinking 'This is weird, I don't usually have to do this', but being only a simple brain, it thought no further. If my brain had bothered to continue the thought to 'I wonder why?...' I might have realised and put down the wheel --- or maybe not.

Steve, I had not read your post on this thread, so I am sorry for not having congratulated you for a good idea. That additional microswitch seems so sensible. Could you possibly take a photo and post it for us please?
One picture being worth a thousand words etc.

Of course, what we really need is a big red banner that pops up from the upper cowling to obscure the forward view if our height gets below 200 feet and the wheel is not securely locked down.

And I guess some days I might not even notice that!