BeechTalk - BT

Username Protected · **Posted:** 08 Aug 2021, 17:25

The Continental CD 300 has a TBR (Time Before Removal) of 1,200hrs. They are shooting for a 2,000hr TBR. What general aviation airplane has a Time Before Removal? Am I mis-understanding this? Do you have to replace the entire engine and I would assume all its components at 1,200hrs? Why not TBO?

Username Protected · **Posted:** 10 Aug 2021, 19:25

TBR is actually "time before replacement". the problem is the aluminum block where the headbolts etc eventually pull out. aluminum unlike steel will eventually break if it is in tension (it has no fatigue limit below where it will virtually last forever) so the trick is to trade off weight for life time. all ferrous steel, cast iron engines where the parts in tension are steel will last far longer. the iron engines built by Diamond will go far longer than the continental aluminum block engines.

Username Protected · **Posted:** 10 Aug 2021, 20:57

Nice airplane, no doubt about that.

My airplane is faster, more useful load, comparable avionics, better short field performance, better mechanical support, 1/4th insurance cost and $1m less.

For the $1m savings I can fly my plane for the dividends I earn per year and still keep the $1m.

For $1.3M I will have a turbine on the front and will have another 100 knots cruise. I don't understand why anyone would buy a $1m+ piston airplane.

Username Protected · **Posted:** 10 Aug 2021, 22:36

Username Protected wrote:

Nice airplane, no doubt about that.

My airplane is faster, more useful load, comparable avionics, better short field performance, better mechanical support, 1/4th insurance cost and $1m less.

For the $1m savings I can fly my plane for the dividends I earn per year and still keep the $1m.

For $1.3M I will have a turbine on the front and will have another 100 knots cruise. I don't understand why anyone would buy a $1m+ piston airplane.

Ya, I don’t think they thought this one through enough. Piston, pressurized Mirage for the same price and faster, or not.

Chip-

Username Protected · **Posted:** 10 Aug 2021, 23:31

Username Protected wrote:

Nice airplane, no doubt about that.

My airplane is faster, more useful load, comparable avionics, better short field performance, better mechanical support, 1/4th insurance cost and $1m less.

For the $1m savings I can fly my plane for the dividends I earn per year and still keep the $1m.

For $1.3M I will have a turbine on the front and will have another 100 knots cruise. I don't understand why anyone would buy a $1m+ piston airplane.

Ya, I don’t think they thought this one through enough. Piston, pressurized Mirage for the same price and faster, or not.

Chip-

Username Protected · **Posted:** 11 Aug 2021, 10:48

DA50 makes little sense to me. DA62 I like a lot and makes more sense.

The star here is the engine, in my opinion. I hope it does well and finds its way into Navajos and other twins via some stc.

Rgs,

Patrick.

Username Protected · **Posted:** 11 Aug 2021, 14:12

Is the 300HP engine in the DA50 a compression ignition diesel or a spark ignition diesel? The stats say it is 15.5:1 compression which I believe is too low to be compression ignition. One of the beauties of diesel is eliminating the ignition system.

Username Protected · **Posted:** 12 Aug 2021, 10:32

Doesn’t the Raptor double this performance for 1/10th the money? :scratch:

Username Protected · **Posted:** 12 Aug 2021, 12:35

Rocky, they taper the tail boom like that to reduce drag, and it’s super effective. The tail is plenty strong, so it doesn’t need to be any bigger.

Diamond’s designs all trace back to their motor glider designs, which have a similar shape. Egg-shaped pod for the occupants and a narrow tail boom to reduce drag.

Username Protected wrote:

So I’m not an aeronautical engineer but why do they taper down the fuselage before the tail. Seems it would be so much stronger if they didn’t. But being a guy that has broke the tubes to the tail section, can you folks tell me?

Username Protected · **Posted:** 12 Aug 2021, 13:28

Username Protected wrote:

I wonder if some of this isn't akin to the "restaurant price" syndrome. My son recently asked me why pancakes at a Chicago restaurant cost so much, and why they gave us so many when we couldn't eat them all. I said that we weren't paying for the ingredients in the pancakes, or the number of them on the plate. Rather we were paying for the rent on the restaurant in a very expensive city, the electricity, payroll, etc. The pancakes were a tiny fraction of that cost. They gave us so many because the incremental cost to them was tiny vs their overhead, and it made us feel like we were getting something for our money.

Great point. It's also a bit of a chicken and egg problem. Kind of hard to get down the per-unit cost without selling more units, and of course that won't happen unless the airplanes become cheaper.

Username Protected · **Posted:** 12 Aug 2021, 15:42

Username Protected wrote:

So I’m not an aeronautical engineer but why do they taper down the fuselage before the tail. Seems it would be so much stronger if they didn’t. But being a guy that has broke the tubes to the tail section, can you folks tell me?

Username Protected · **Posted:** 12 Aug 2021, 15:48

Username Protected wrote:

The small tail boom makes for some very high crosswind capability. The DA40 was exceptional in crosswinds.

Yep. A ancillary effect is the small profile makes less drag when the airflow is sideways. It can be an adjustment when pilots transition from traditional designs into clean designs like this one. They don't lose airspeed as quickly, and when you try to slip to lose altitude it seems like nothing happens.

Username Protected · **Posted:** 13 Aug 2021, 03:50

I am completly baffeled as to why no one can bring to market a Light GA aircraft that is more efficient than the Columbia 300 that was certified in 2000.

175K TAS @ 12g/h giving a range of over 1,000NM (110gal)

or

195K TAS @ 16g/h giving a range of over 1,000NM (110gal) for the Columbia 400/Ttx .

This DA50 does'nt even come close.

Username Protected · **Posted:** 13 Aug 2021, 10:10

Username Protected wrote:

Is the 300HP engine in the DA50 a compression ignition diesel or a spark ignition diesel? The stats say it is 15.5:1 compression which I believe is too low to be compression ignition. One of the beauties of diesel is eliminating the ignition system.

The CD300 is a common rail injected, compression ignition engine. One shortcoming is that it is only rated for 268 HP continuous power, so it will not easily replace a 300 HP avgas engine. Another problem is the weight. It's 584 pounds, compared to 490 for a 300 HP Lycoming TIO540, or compared to 522 lbs for a 315 HP Continental TSIO550K.

Swap a pair of CD300's on your Baron, and gain over 200 pounds empty weight.

There are many diesels with lower ratios. Mazda's newest diesel has a compression ratio of 14 to 1. Only slightly higher than their 13 to 1 compression ratio gasoline engines.

Username Protected · **Posted:** 13 Aug 2021, 10:14

Username Protected wrote:

I am completly baffeled as to why no one can bring to market a Light GA aircraft that is more efficient than the Columbia 300 that was certified in 2000.

175K TAS @ 12g/h giving a range of over 1,000NM (110gal)

or

195K TAS @ 16g/h giving a range of over 1,000NM (110gal) for the Columbia 400/Ttx .

This DA50 does'nt even come close.

Michael, how much load can the Columbia carry with enough fuel to fly 1000 nm?

DA 50 RG