Again ... you are talking about TAS and I asbolutly agree about the relation between TAS and climb rate. However IAS is influenced by installation and instrument errors and density of air. The "design relationship" cannot take these factors into account, hence there is no direct relation between IAS and rate of climb.

TAS and climb rate are in relation.
TAS and IAS are in relation.
But there is no direct relation between IAS and climb rate. For example: IAS changed becaused by a frozen pitot tube, but this will not change the climb rate.

I want to make clear that I do not want to say that IAS is mathematically constant for a theoretical maximum rate of climb. I absoluty agree with you that theory says is is decreasing. However what I want to say is that there are pratical references that indicate that for a specific aircraft the IAS for maximum rate of climb can be near constant over a certain altitude range.

Bingo!

Which was stated prior to crump stating it so he actully agrees with what was allready said, yet his replies thus far seem to be ingnorant of the fact that it was allready stated prior to his statement.

Who told you it was "near constant"??

The rule is Vy will be reduced 1 KNOT IAS per 1000 feet altitude. Vx will increase 1 KNOT IAS per 2000 feet altitude.

From sea level to 20,000 feet...

Vy changes 20 KNOTS, 23mph, or 37kph.....

Vx changes 10 KNOTS, 11.5mph or 18.5kph....

See above post......

There is no theory to it. We are not talking quantum physics. Get a pilots license or go to school to learn about airplanes. Stop getting your information from these gamer discussions about virtual planes from folks who have never even smelled avgas.

It is a very simple concept that does not require an indepth discussion.

Climb speeds change with altitude.