The 1980+ 421C spar was a slight material change, SID compliance times had nothing to do with the TL gear.

The SID program for the 421 is a joke. Came about due to faulty analysis, there is nothing wrong with the spar in twin Cessnas despite the SIDs and AD afflicting 402C, 414A. There has NEVER been a spar failure of a twin Cessna caused by fatigue.

NEVER.

All the twin Cessna spar failures can be traced to exhaust problems (a number of these which brought about the exhaust AD) or a latent manufacturing defect (the Goldsby, OK accident).


Marketing. The same thing is happening today with winglets. The market pull is stronger than the actual intrinsic value.

There was also a decade switch at the same time to explain the premium of a 1980 421C. A 1980 airplane is worth more than a 1979 airplane even if they are otherwise identical because of that, and the 421 SL to TL conversion happened with the 1980 model year. Same thing happens 1969 to 1970. Market psychology.

There are a lot of subtle issues with TL gear. Side loads and braking, for example. When Cessna switched the 560 from SL to TL (Citation V Ultra to Excel), the braking effectiveness was reduced. ABS and TL can interact in weird ways because braking is both drag and a torque on the trailing link arm.

There is no functional advantage to TL gear.

Mike C.

I think the TL sits higher, so if anything, maybe more prop clearance.

Marti,
You are correct. We have my B model and two C in my bulk hangar( one TL and one SL) the th TL sits slightly lower than my B model and the SL is significantly lower. You can really see the difference when you have the air stair doors open and see how close the the ground they each are...

Hello 421 drivers,







I would be intersted in this. Would a B outperform a C at the lower altitudes.

What kind of speed and fuel burn would you get at those altitudes.

Is a 1000nm trip feasable at those lower altitudes.



Thanks for the input.

There might be measurable differences between a B and a C, but I doubt they are 1) operationally significant or 2) overwhelm individual engine/airframe variation.

Without structural data it's hard to say for certain but I don't necessarily see why TL would cause a bending moment that doesn't exist with SL under heavy braking or when a main wheel encounters a small obstruction (think large gopher hole in a sod runway).

Certainly in the static condition the TL has a bending moment but it's limited by the spring force vs the SL where there isn't much to "release" an aft bending force.

I would be intersted in this. Would a B outperform a C at the lower altitudes.

What kind of speed and fuel burn would you get at those altitudes.

Is a 1000nm trip feasable at those lower altitudes.



Thanks for the input.



A B will climb better than a C. A C gets its speed benefit over a B above FL210. I typically flew My B between FL160-175, and trued between 207-217 depending on temps, burning 43gph.

Today...
Right engine likes a little more fuel than left, anxious to see how that plays out LOP.

Everyone take note of those CHTs at FL210 doing 220+kts ROP! 319 and 326 are the high for each engine with most around or below 300dF.

You will not see that in a 414 or 340 ever...especially on an ISA +20 day.

Hello Jack,








Curious, is this a B or a C model.



And to the rest of you, thanks for the quick responses.

Keep them coming.

I have flown a 421A, 421B, 421C SL and a 421C TL. I have never seen or heard of a 421B out performing a 421C at the same Gross Weight and Density Altitude.

Looking at your attitude being so low for a 421 , do you have Strakes or winglets? Also to the poster that asked this a 421C

How do those engine monitors come up with 86% power at those settings? My performance tables show in the high 60's - 70%

Hello Gerald,







Thanks for the response.

With your experience, what is your take on the differences between the B and the early C models.

Is there any difference.

There seems to be quite a difference in price points between the two models.

And one would think there is a difference without those big tip tanks out there.



Thanks.

Everyone take note of those CHTs at FL210 doing 220+kts ROP! 319 and 326 are the high for each engine with most around or below 300dF.

You will not see that in a 414 or 340 ever...especially on an ISA +20 day.