Mr. Earle-
Any update on that 'over the top' Aztec you mentioned you were going to be selling?
Still curious.
Here is an F model with a $439k ask...wow, that is one proud owner!
https://www.controller.com/listing/for- ... n-aircraft
I'm renewing insurance this month and need to make decision on the hull value. Broker said if i reach too far the underwriter is going to want a darn good presentation to even be considered.
Cheers.
Mark

I'm experiencing a burnt rubber smell upon gear retraction in my new to me 1972 Turbo E. Has anyone else experienced this? I suspect it's because I'm not tapping the brakes before I bring up the gear. Input appreciated. Daniel

You’ll probably see it on your gear doors if that’s the issue

brakes will not help here.
there is a rub strip in the nose wheel well that stops the nose tire when the gear is retracted. That's where the smell originates. It's not bad, it's just working as designed, but it freaks out passengers.
The fix is to NOT immediately raise the landing gear after takeoff, when the wheel is still spinning at high speed. Give it 30 seconds or more to slow down. Or, you can increase the wheel bearing tension by tightening the axle through bolt, which will slow the wheel more quickly after lift off. Another tip- don't leave the plane on the runway longer than necessary, it just speeds up the wheels and wears out the tires. You should be in the air, in ground effect, at 70 MPH. I've seen plenty of pilots leave it on the ground till 85 MPH or more before lift-off. Bad technique.

I Didn’t know that’s what that was!

Great information. Thanks Glenn. I'm leaving it on the runway too long before rotating

Not sure I agree with rotating before 80mph (70kts). The book performance numbers are based upon rotation at 80mph.

Your plane, your decision, but I'm sticking with the book, actually I prefer Vmc+5.

Jeff

I'm VMC +5 as well....69 knots.

She flies off smoothly with very little back pressure. My home base has 9,000 feet and i only use full length. With that much room, i let the tires spin down a bit before retraction.

Tighter conditions i'll tap the brakes and suck 'em up right away.

Mark

Yes, let's correct that. Mixing knots and MPH gets hazardous since all the older ones are marked in MPH and newest ones in knots. Vmc is 64 knots, 74 MPH on F models, but it is 80 MPH, 69 knots, on earlier models.

Rotating at 65 to 70 knots is where you want to be, based on weight. The plane accelerates quickly in ground effect so you can climb out above blue line. But I see pilots trying to hold the plane on the ground well past Vmc which just beats up the nose gear. I think they're trying to reach blue line on the ground.

Pretty sure VMC in my '78 F model is 64 knots (?).
Mark

My calculator says 80mph is 69.518knots so you decide 69 or 70, I can't tell that fine of a difference on the airspeed indicator, but that's splitting unnecessary hairs.

This comment makes more sense, your original message made it sound like you were rotating before Vmc and then building airspeed in ground effect before climbing out.

As I said I rotate at Vmc+5 even though the book recommends Vmc which is 80mph (D model in MPH), although in reality once you hit 80, 85 is only a split second later anyway. I will then do a shallow climb until blue line (102 mph) which is what I think you meant by staying in ground effect to allow the airspeed to build before pitching up to 120 (Vy) to climb out.

The book take-off performance numbers are based (again D-Model MPH) rotation at 80mph (Vmc) and being able to cross the imaginary 50ft obstacle at 97mph.

In reverse on landing the book says to cross 50ft over the runway threshold at 86mph and touchdown at 68Mph, this should result in a touchdown at the aim point markings, 1000ft down the runway. I'll admit that will burn a lot of runway and I plan on crossing that 50ft "barrier" before the runway threshold for shorter runways, but never below blue line until I'm on final and never below Vmc until the runway is made.

I'm sure other people have their own techniques that work for them and they are comfortable with, I'm aware of some Aztec drivers that use flaps on very short runways and other stuff not listed in the book, again to each their own. If I need to go into a runway that I feel is too short for the Aztec I'll "steal" my friend's Arrow. I've learned it really isn't the landing distance, it is the takeoff distance, in order to take advantage of the second engine you need to adhere to certain speeds, go below those speeds you are in no better shape than if you were in a single, possible worse shape as a single isn't going to flip upside down performing a Vmc demonstration for you.

Jeff

To add a new topic within this thread, FUEL GAUGES, every now and then I hear people complain that the fuel gauges don't read full when the tanks are actually full. I went through this a few years ago and learned how the gauges actually work and was able to correct the issue. I'm sure this will be of great help to others. Of course I make no claims of warranty or fitness, but I think once you read through my ramblings you'll understand how the systems works and where the problem usually lies.



Below is an image of a balanced coil gauge, same as what is used in the Aztec and probably most airplanes with non-digital electric fuel gauges. The gauge is NOT an OHM meter. this gauge is showing Hot/Cold, but if you replace the C with F and H with E it is the same gauge.

The way this gauge works is coil A is always energized at full strength which pulls the needle to the Full indication. Coil B has a variable strength which is controlled by the resistance to ground going through the fuel sender. Basically what you have is a tug of war between the two coils, Coil A wants to always pull the needle to full while coil B tries pulling the needle to empty. The less resistance you have going through the fuel sender to ground the more powerful coil B becomes and pulling the needle to Empty. This is also why if you disconnect the wire at the fuel sender the fuel gauge will read over full as coil B is not generating any force to counteract Coil A.

In order for this system to work properly both coils need a good solid ground, if Coil A's ground is compromised then Coil B will be too strong and will not be counteracted by Coil A resulting in the fuel gauge reading too low.

The power feed to the gauge never becomes an issue since both coils receive their power from the same feed line and because the needle movement is based upon the strength of the coil's pull to each other it doesn't matter what the input voltage is as long as it is the same. In other words the input voltage to the gauge doesn't matter it can be 9 volts or 30 volts (as long as it is within a value that won't destroy the coil) the gauge will be accurate.

This is why I am saying that there is a bad ground to the gauge, because the gauge appears to be functioning and is simply reading too low this is telling me that coil A is too weak, yes it is possible but highly doubtful that the gauge is failing, when they fail I would expect the needle to be pegged either empty or full, not continue to move with the fuel quantity. Had the gauge read over full I would say that there is a break in the wire between the gauge and the sending unit. In addition, when a sending unit fails it will either fail "open" or have one or more "dead spots" on it which again would cause the fuel gauge to read over full.

Lastly there is a small capacitor on the back of the fuel gauges, this capacitor is simply used to dampen the needle movements from sloshing fuel.
The gauges are mounted in an aluminum tray, this aluminum tray provides the ground to the gauges. The gauges have a brass contact on the back which is the ground. Over time the aluminum will oxidize and so will the brass on the back of the gauge both of which will compromise the ground to the gauge and in turn weaken coil A.

When you go and clean the back of the gauge and the aluminum tray you might consider a very thin coating of "NO-OX-ID" to prevent future oxidation.

Hope this helps somebody from spending time and money when troubleshooting their low reading gauges.

Jeff

Finished up annual inspection on 4MM. Ready for another 12 months of Aztruckin’

Another view of Mike Mike truckin' in for landing.

Fuel Selector, Cowl Flap placards. Black Anodized aluminum, with white lettering.

Beat up, faded placards, worry no more.

We have some in the works, If anyone else needs them let us know.