What's the latest on the Extra 500?

Yeah, FF’s can be high at idle/taxiing. It’s about 100pph/side on the Commander (30gal/hr), so it pays to get airborne quick!

@lionel
Yes it does, because engine now produces less power. If I recall correctly, at 17000ft on mine, we’re now down to about 300hp/side, compared to the rated 665hp/side at SL. So it’s a big drop.

In essence, as a comparison to what the TBM 850 does, I could achieve the same effect if I limited my takeoff power to about 80 degrees lower (from 545 to 465 C) and then processed my performance numbers for that. The TBM is a 850hp plane, but you are temp limited and can only use 700hp for takeoff. So it’s really an exercise in numbers, limits and marketing rather than actual power. Ask yourself this – wouldn’t you rather have had that full power available on takeoff? I would. It would shorten my takeoff considerably. Now TBM has chosen to limit you there, just so that their cruise numbers look better and it looks like it doesn’t fall off as much. But it’s just numbers fudging.

As a complete aside, interestingly, on the TPE331 engines, each 1 degree of EGT or ITT temperature, is worth about 2hp’s (or 1hp/side). Another thing – and this is mind boggling – is that 70% of the power the hot section produces, goes to sustain itself. Only 30% can be used as the propulsive power. So in the case of my 665hp engines, they’re actually thermodynamically 2200hp engines at the core, but the 70% goes to just run itself. This gives a clue why they’re rather inefficient compared to pistons.

@loco
How much power is available for T/O on the 900 models? The full 900?

Wasn’t talking about losses necessarily, just how much power is needed to sustain it’s own compression stage to keep going.

So sad that that aircraft didn’t reach a wider audience or its full potential before Extra went belly up. It deserved a better fate.