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Cessna 400 TTx deliveries started (and production ends)

At low level, they are almost the same.

I don't need an ADC; I have a knob in the LH corner of the ASI.

Administrator
Shoreham EGKA, United Kingdom

realize that IAS is completely meaningless

It isn't if your task is the design of a low-drag fixed gear...

Over the years the owners of aircraft I have flown so far (including myself) have spent the equivalent of a nice little house (or even a villa) in pleasant surroundings to fix retractable gear related problems and some of the consequences that came from it - including a gear collapse on a Cessna 421 in an attempt to tow it to the maintenance hangar after I had to land it with "two greens" only. So I think Cessna really knows why they keep it as simple as they can nowadays :-)

BTW: There are some highly successful fixed gear turbine aircraft, single and multi-engine, as well like the Caravan and Twotter.

EDDS - Stuttgart

The wings need to be thick enough only on the inboard portions. You make the wheels go underneath the hull, so only the "bit above the wheel" needs to fit into the wing.

Folding the 'tyres' into the hull produces a narrow track - reduced stability. Making the track wider and folding (inwards) the whole lot into the the thickness of the wing (root) is more stable on the ground. PA28R's have the 'whole lot in the wing'.

Regret no current medical
Was Sandtoft EGCF, North England, United Kingdom

It works just fine in the TB20, which has a 25kt max demo crosswind limit. I have not cancelled, due to wind, a single flight since I bought mine in 2002.

Administrator
Shoreham EGKA, United Kingdom

They will be bits of bent-up ally, riveted into subassemblies

I'm not an english speaker, what do you mean by that?

The issue goes up exponentially as one goes faster

I thought only quadratically? Which is bad, but a lot less so than exponentially...

LSZK, Switzerland

Apologies

Ally = slang for aluminium

Here is a piece of bent up ally with some rivets

It's the sort of labour intensive thing which planes are full of, since before WW2, and you could build it in quite a few places in N Africa... with appropriate "local supervision"...

I thought that a quadratic is a special case of exponential - isn't it? My maths was always crap though.

Administrator
Shoreham EGKA, United Kingdom

I thought that a quadratic is a special case of exponential - isn't it?

Then linear is another special case of exponential, raised to a power by 1

Here is a piece of bent up ally with some rivets

I think the biggest improvement in manufacturing technology was achieved by Eclipse and its stir welding process. The whole composite thing hasn't really paid off so far. The Cirrus is damn heavy, zero gain from being composite and the same holds true for the Diamond stuff.

The Boeing/Airbus composite process seems to be much better but they are still reluctant.

Then linear is another special case of exponential, raised to a power by 1

So was I right (serious question)?

zero gain from being composite

I think the SR22 gains a lot from the composite (no pun intended) curves which are possible with metal but only with very expensive tooling.

The SR22 does a similar MPG to the TB20, despite the fixed gear. And the Cessna 400 I flew in did exactly the same too - 140kt IAS at 11.3 GPH, peak EGT.

If you can narrow down the cockpit quickly as you go towards the rear, you gain on drag.

Administrator
Shoreham EGKA, United Kingdom

Ally = slang for aluminium

Thanks! Neither m-w nor urbandictionary knows this meaning of ally.

And I thought I didn't want to be your ally if you bend and rivet me 8-)

Then linear is another special case of exponential, raised to a power by 1

The way I was thought was that exponential is this kind of thing: exp(x) (or e ^ x).

What you mean is what I would call polynomial (or power series).

LSZK, Switzerland

However I would say that the "complexity" of having to make sure the gear is down before landing, and leaning the mixture very occasionally, is negligible compared to the knowledge required to utilise the modern avionics.

Indeed, and with modern avionics it should be much easier.

In the Arrow that I fly, we get a warning horn if the gear isn't down and either a) the power is reduced below a certain level, b) flaps are deployed.

That was probably as much as they could detect in the 70's.

But with modern avionics, it should be trivial to detect that

  1. the aircraft is reaching the airport destination in the flight plan, or
  2. the aircraft is approaching an airport and is desending towards the airport altitude
  3. Has tuned in the ILS
  4. Probably a host of other combinations that indicate it's likely to land there.

That way a more meaningful warning could be given that indicated that the systems has more of a reason to believe you'd forgotten the gear than simply aircraft configuration.

EIWT Weston, Ireland
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