Mark Z
Well-Known Member
18 GPH on takeoff power would cook my TSIO 520. I’m looking for no less than 32, preferably 34 out of the hole; 22-25 in the climb. However, I know nothing about Diesel engines.
He may well be cooking his 3.0 TDI as well. At that fuel flow he should be seeing upwards of 350-400HP with a properly matched turbo/intercooler setup. Though he didn't provide any engine data, previous runs have reflected high EGTs. If he really wants to use that engine, spending more time resolving his high EGTs and low thrust should be a priority - followed by a reasonable amount of run time at full power before progressing to any part of the aircraft leaving terra firma.18 GPH on takeoff power would cook my TSIO 520. I’m looking for no less than 32, preferably 34 out of the hole; 22-25 in the climb. However, I know nothing about Diesel engines.
Yes, unless the prop setup is garbage he is making 200 +/- hp and blowing the rest of the fuel into the turbos!He may well be cooking his 3.0 TDI as well. At that fuel flow he should be seeing upwards of 350-400HP with a properly matched turbo/intercooler setup. Though he didn't provide any engine data, previous runs have reflected high EGTs. If he really wants to use that engine, spending more time resolving his high EGTs and low thrust should be a priority - followed by a reasonable amount of run time at full power before progressing to any part of the aircraft leaving terra firma.
Wasn’t the Mark Z’s comment meant to say that 18gph is running too lean, and not too rich, or did I misunderstand?Yes, unless the prop setup is garbage he is making 200 +/- hp and blowing the rest of the fuel into the turbos!
Diesels don't run 'lean'. They either have enough air to complete the burn or they don't. If there is excess air then it is a complete burn. If not there is smoke. 18 gph is equivalent to 350+ hp if there is enough air to burn it.Wasn’t the Farmboy’s comment meant to say that 18gph is running too lean, and not too rich, or did I misunderstand?
Too much fuel is what kills a diesel. Get too close to stochiometric, it will fail. Black smoke is a warning sign. On some of his run ups, you can see black smoke in the prop blast. There is no such thing as too lean for a diesel. The Raptor is using an awful lot of fuel for it's apparent 200hp. That extra fuel will be heating something up way past its design point.The turbos are completely wrong, which is strangling the engine. It would work a lot better with one of them removed. Peter rebuffed Ross's turbo advice offer.Wasn’t the Farmboy’s comment meant to say that 18gph is running too lean, and not too rich, or did I misunderstand?
If your 520 was capable of running diesel bsfc numbers then it would be making upwards 550 hp.18 GPH on takeoff power would cook my TSIO 520. I’m looking for no less than 32, preferably 34 out of the hole; 22-25 in the climb. However, I know nothing about Diesel engines.
Ok, that clears it up. Thx.Sorry, in post#1786 i was referring to post#1781, and I accidentally attributed Marc Z’z comment to Farmboy. That has been corrected now.
Just to confuse things a bit more, there's "Mark Z" and there's me - Marc Z. Note the first name spelling difference - some folks just spell their names incorrectlySorry, in post#1786 i was referring to post#1781, and I accidentally attributed Marc Z’z comment to Farmboy. That has been corrected now.
AAAAARRRRRGGGHHHH!!!Just to confuse things a bit more, there's "Mark Z" and there's me - Marc Z. Note the first name spelling difference - some folks just spell their names incorrectly. We're NOT the same person, I don't think.
Ya but you're using a lot of excess fuel to cool the engine. His engine has liquid cooling.18 GPH on takeoff power would cook my TSIO 520. I’m looking for no less than 32, preferably 34 out of the hole; 22-25 in the climb. However, I know nothing about Diesel engines.
Not enough liquid (or low static pressure radiator area) to keep from melting his pistons if he continues to run excessive EGTs.Ya but you're using a lot of excess fuel to cool the engine. His engine has liquid cooling.
That’s right, I overlooked that. So what would be a good fuel burn quantity (gph) to get his advertised HP?Ya but you're using a lot of excess fuel to cool the engine. His engine has liquid cooling.
Peter has been calculating his hp from fuel burn, using a slightly optimistic BSFC for a well tuned engine. His engine is a long, long way from well tuned. Fuel burn might be ~5% higher for an engine actually producing his claimed hp. Thrust figures suggest that he is making somewhere around 60% of the power that he has calculated and claimed.That’s right, I overlooked that. So what would be a good fuel burn quantity (gph) to get his advertised HP?
I’ll answer to anything especially a call to dinner.
Which is why the first flight is always interesting. Will have to run full power for at least 2-3 minutes and deficiencies in cooling are one of the first things to show up.Not enough liquid (or low static pressure radiator area) to keep from melting his pistons if he continues to run excessive EGTs.
It's been a long since I have run a TSIO 520 but the IO 520 Operator Guide had some charts for fuel flow and BHP. I'll see what those have to say.That’s right, I overlooked that. So what would be a good fuel burn quantity (gph) to get his advertised HP?
I’ll answer to anything especially a call to dinner.