Trim is for cruising

[Ed Cesnalis]

...Carbon fiber is lighter and has far less drag than metal and rivets. .... its the ESSENCE of why the argument rages over the DIFFERENCE in flight characteristics between old metal craft and the FD.

 

Drag comes from shape it is not a feature of a material, you can build a high drag composite or a low drag design from aluminum. Your statement is not even wrong.

 

There is no such argument raging, what are you talking about, can you supply a link?

 

If you are not willing to supply links or sources for your controversial claims can you say so?

[FlyingMonkey]

Carbon fiber has real disadvantages. It can absorb moisture and lose strength. It loses strength at a far lower temperature than aluminum (aluminum loses 50% of its strength at 400°F...how much strength do you think CF has at that temp? It probably catches fire before that). Carbon fiber is tensile, while aluminum is ductile.

 

Aluminum has a yield strength at which it will bend into a permanent set but not break, which is typically where ultimate limits are set for aircraft. This means that when an aluminum wing reaches its ultimate load limit, it will often bend without breaking. You see this when aircraft land with wrinkled skins and bent spars. But they LAND.

 

When a carbon wing reaches its ultimate limit, the brittle (tensile) carbon SHATTERS. It is done, shredding in a spectacular fashion. Here's an example, the Dreamliner wing destructive test:

 

http://www.youtube.com/watch?v=sA9Kato1CxA

 

After the wing failure, look at the top of the wing, it has broken off in giant flakes. You are not going to be landing that airplane. The CT series has a service limit of 4g positive, so using the FAA 50% rule, we can surmise that the ultimate limit of the wing is about 6g or more, very similar to the limits on a 172 or Cherokee. The difference is when you hit that limit in those airplanes, you have a very good chance of continuing to fly and land. In the CT you are finished, I hope your BRS repack was done by a tech who was not hungover that morning.

 

So is carbon fiber the magic special sauce for all future structures? Ferrari does not think so, and estimates that by switching from CF to aluminum they will DECREASE weight by 15-20% and INCREASE strength:

 

http://www.popularme...errari-says-yes

 

Hell, even FD made an aluminum airplane after years of being the poster child for CF aircraft. Why? Ease of maintenance for flight schools; repairing CF is difficult and expensive. Carbon fiber is an awesome material, both light and strong. But it still obeys the laws of physics and has its own limitations.

[Mick]

At last - someone with what sounds like intelligent engineering. (after 15 + yrs as a flight test engineer in a major A/C mfg. it's good to hear something I can relate to)

[Farmer]

While in auto pilot with the Dynon 6.0 that female voice in your headset tell you when to trim, and she is very fussy. It is going too take a little while to get used too but so far she is always right. With the proper bug setting and a little planning your can line up on final when cleared for a not standard pattern approach. She will tell you when to trim.

 

Tropical storm passed last night and watered some field for us, no damage.

 

 

Farmer

[sandpiper]

Now, I may be wrong about this, but my assumption is that if you have a composite plane like the CT or Cirrus that keeping it hangared is more important than it would be for an aluminum airplane.

 

Does this assumption have merit??

[FlyingMonkey]

I would think so John. Heat and UV are tougher on composites than aluminum, which is one reason you see no black CTs. Carbon fiber seems to have less issue than fiberglass or other composites, but probably still has some long term vulnerability if left out for years. The Diamond aircraft actually has a heat sensor under the seat you are supposed to check before flying; if it's tripped you are supposed to wait to fly until it cools down. I don't remember the temperature, but it is surprisingly low...maybe 120°F? I know here in Georgia hitting that temp on a hot ramp in the summer could be a daily occurrence.

 

Craig told me the other day the Rutan canard designs are only approved for two colors, white and a *very* light blue, for heat/UV reasons as well.

[Ian]

"Carbon fibre is lighter....."

 

mmm I'd generally say that 1kilogramme of Carbon fibre weighs pretty much the same as 1kilogramme of Aluminium but I'm willing to be proved wrong?

[Doug G.]

Is it always the left tank that drains on all our planes? I know that a couple of causes of the problem are a) the mushroom being slightly out of kilter, and the EFIS being mounted crooked in the panel. It seems that those could be either left or right.

[Doug G.]

mistaken emoticon guess I have to use 2) instead of b ) which comes out

[sandpiper]

Is it always the left tank that drains on all our planes? I know that a couple of causes of the problem are a) the mushroom being slightly out of kilter, and the EFIS being mounted crooked in the panel. It seems that those could be either left or right.

 

Mine is always the left tank. Is it me with a heavy foot, out of roll trim, or the plane? Perhaps I list when I walk & fly. I know Roger does.

[Jim Meade]

Gliders all almost universally white for the same reasons given above.

[Doug G.]

When the brits did a study on what color was the most difficult to see by subs in WWII, they found out it was white. Looking down white is easier than some dark colors, looking up, not so much.

[FlyingMonkey]

Chris,

 

My plane used to do this. Then my mechanic found that my Dynon was not installed perfectly (the ball was not centered when the plane was level). After a small adjustment to the level of the Dynon, the tanks now drain equally (ball is now centered when the plane is level).

 

Of course, your plane may be different than mine.

 

Fred

 

How do you adjust the ball? My airplane sitting on my hangar floor shows the ball between the brackets but slightly to the left side. I'm thinking adjusting that might help a little. I looked through the setup menus but could not find a slip/yaw/ball setting. I also thought about getting a physical ball and putting it on the panel above the Dynon where it would be more in view if I quickly glance down.

[Ed Cesnalis]

it is a slip/skid ball not a wings level ball. I put a yaw string under my wing, it needed a piece of tape at the trailing edge to tell when I was coordinated.

 

In the end I learned that my EFIS ball was good but my physical ball was biased.

 

I still have to manage my fuel sometimes and most of the time it drains close to equal. Even if your slip skid ball is right the pilot needs to be perfect.

[Jim Meade]

Hmmm, Doug, I don't think it was white. As I recall, it was a dirty, more or less cloud similar color. Maybe we can find the reference. Just as black ships are easier to see on a normal night than a "battleship grey" ship. The desire is to have the color blend in and not provide contrast with the background.

[FlyingMonkey]

it is a slip/skid ball not a wings level ball.

 

Yes, but shouldn't it be dead nuts centered when stopped on the ground. The airplane is not yawing in that condition. Mine is not quite there, it's a hair to the left. Not enough to worry about, but if I can easily adjust it to read perfectly, why not?

[Doug G.]

I wish I could give you a reference, but it was on History, or Discovery. I can't vouch for their accuracy. (Or even my memory. )

[Doug G.]

When I saw this set it was done with a digital level on the wing (leading edge?) then again on the console to check the level of each. The resetting consists of either leveling the mushroom, or redoing (cutting the opening if necessary) the mounting of the EFIS.

[FredG]

Andy, according to Dynon, the ball in the D100 is not user adjustable.

 

So, my mechanic had to adjust the horizontal level of the Dynon on the panel after carefully leveling the wings. In my plane, with wings level, one side of the D100 was lower than the other and the ball (as you expected) was not centered. With 1.7 degrees of dihedral angle, it only takes a couple of degrees (or less) from level to transfer fuel from one tank to the other (or, in flight, to create the impression that one tank is draining faster than the other).

 

Also, many planes, even in well built hangars, do not sit with wings perfectly level when the wheels are on the floor (hangar floor not perfect, landing gear not perfect, etc).

 

So, your mechanic needs to level the wings with quality measuring equipment and then check the level of the D100 housing and the position of the ball. If the D100 housing is level when the wings are truly level, and the ball is centered when the D100 is level, then your ball calibration is good (at least for the static test). I belive this is not a procedure that owners who are not LSRM or higher are allowed to do on their own.

 

As always, check with your mechanic before doing anything you are not certain is allowed for your level of training and certification. Also, Dynon has a useful forum with Dynon techs available to answer questions.

 

Fred

[Ed Cesnalis]

Fred,

 

How is dynamic testing done? I tufted a wing.

 

Andy,

 

I should have said: it is a slip/skid ball not a 'is the floor level and are my gear legs perfect and are my tires perfectly matched' ball.

[FredG]

CharlieTango,

I don't know. I think only Dynon has that answer.

Fred

[FlyingMonkey]

LOL CT, point taken. I'm guessing any of the factors you cited could be at play. And mine is only barely shifted to the left, so could easily be anything.

 

Thanks FredG, I guess if it's not adjustable, I won't adjust it!

[Roger Lee]

The only way for us end users to adjust the D100 is to move or turn it in the mount or panel. No other adjustments. The plane would need to be leveled and the D100 moved. It usually isn't worth the small amount it may be out and then the next time someone gets out of the plane and pushes on the instrument panel which happens a lot then it may be out again. The instrument panel is not a solid mount.

[Tom Baker]

Checking the level is something you can do. If it needs adjustment that is something for your mechanic to do.

 

On the fuel feeding issue I look at the wing tips in flight and level them with the horizon. This has always given me even fuel feeding from the tanks.