What is the purpose of twin props/ engine on the lazair?

[Bob Llewellyn]

You could use the propwash directed onto the fin by the two methods I mentioned earlier. If the aircraft is not to close coupled low powered engines shouldn't be much of a problem. I'm not much of a push-pull fan myself. If the engines are well forward they get the thrustlines much closer.My area of interest is a pressurised plenum and blown wing and pressurised air propulsion. Keeps all the mass near the centre no prop to kill dogs and people and little stress from the drive on the engine which could be a high revving motorcycle engine or such. All the cooling and exhaust heat could be utilised. Not sure about the efficiency but it has control possibilities and would suit a glider. too. Nev

Hmmm

 

The Piper Apache had a rate of descent on one engine.

CAR 3 did not require a positive rate of climb on one engine for aeroplanes with stall speed less than 61 knots...

 

 

[dazza 38]

HmmmCAR 3 did not require a positive rate of climb on one engine for aeroplanes with stall speed less than 61 knots...

I guess that is why we have the famous quote of " the second engine takes you to the scene of the accident"

 

 

[facthunter]

It's not really valid with today's aircraft. They have to meet various criteria engine out, but the performance margins are small and the testing is done with a brand new aircraft and a competent pilot. The plane will meet the standard at certification You fly your plane with a lot of rudder to balance it and to ONE knot or so of speed tolerance. This is something most RAAus people would never think of doing as you need the precise weight of the plane to get your speeds to use to make the effort work.. Nev

 

 

[Bob Llewellyn]

It's not really valid with today's aircraft. They have to meet various criteria engine out, but the performance margins are small and the testing is done with a brand new aircraft and a competent pilot. The plane will meet the standard at certification You fly your plane with a lot of rudder to balance it and to ONE knot or so of speed tolerance. This is something most RAAus people would never think of doing as you need the precise weight of the plane to get your speeds to use to make the effort work.. Nev

Yes, I agree most RAAus operators think weight doesn't matter if the strip is long enough... Do28 blue line is below stall at MTOW; this perhaps is the standard to aim for?

 

 

[facthunter]

Gives more control especially at low speeds. If you are for cruise performance minimum rudder. As in DH Mosquito and DH Comet etc.