Re: b-17 left teterboro on 3 engines last night?
Sat Jun 23, 2012 8:57 am
robkamm wrote:What's a windmill start?
You go down the runway as fast as you can and unfeather the prop and start the dead engine. Then you jam on the brakes hoping to stop before you run off the end of the runway.
Re: b-17 left teterboro on 3 engines last night?
Sat Jun 23, 2012 9:23 am
thank you.
Re: b-17 left teterboro on 3 engines last night?
Sun Jun 24, 2012 9:05 am
BTW, windmill and buddy start works on any T56 or Allison 501D-powered aircraft. In fact, it should (in theory) work on any of the Garrett, Turbomeca, or Rolls Royce that is shaft driven (versus the free-turbine PT-6). The only reason it won't work on free turbine turboprops is because simple the prop isn't directly turning the power turbine, so turning the prop is pointless from a starting viewpoint and not enough smooth air is put into the inlet to get the turbine up to speed.
I watched a windmill start of a Convair 580 (it was a procedure demonstration for guys in training). Even empty, it still took a good amount of the 11,000+ foot runway 5L/23R at Rickenbacker to get enough speed and then stop after the engine started.
I watched a windmill start of a Convair 580 (it was a procedure demonstration for guys in training). Even empty, it still took a good amount of the 11,000+ foot runway 5L/23R at Rickenbacker to get enough speed and then stop after the engine started.
Re: b-17 left teterboro on 3 engines last night?
Mon Jun 25, 2012 8:24 am
I know that Chuckie took off and flew from Waco to Fort Worth on a ferry permit in 1987. She had an engine fire in Waco and they elected to bring her back to pull the engine.
Doc told me that they had 2, 3 and 4 running and on the takeoff roll they powered up all three but couldn't hold her straight so the idled #4 and continued on....3 folks and enough fuel on board for the ride home. she was light enough that two were enough for departure. The added in power on #4 in the air and she cruised @ 180mph.
Easy!
Doc told me that they had 2, 3 and 4 running and on the takeoff roll they powered up all three but couldn't hold her straight so the idled #4 and continued on....3 folks and enough fuel on board for the ride home. she was light enough that two were enough for departure. The added in power on #4 in the air and she cruised @ 180mph.
Easy!
Re: b-17 left teterboro on 3 engines last night?
Mon Jun 25, 2012 10:28 am
The dance down the runway (particularly in the sim) has caused more than its share of laughter over the years.
A common technique for the C-130 three engine takeoff is (in short) to hold the brakes and run the two symmetrical engines to max power. Next, bring the other operating engine from idle into the governing range; this is to ensure it's producing positive thrust with any subsequent throttle advance vs. flat blade angle (barn door) drag. Last, put in 90% of full rudder to counter the good engine. Release brakes, initially steering with the nosewheel. Once the rudder comes alive, that nearly full input will start to bite and the airplane will (you hope gently) begin to track off centerline. Feed in a measured amount of throttle to offset the swerve. Accelerate more. As the rudder becomes more effective, it will try to swerve again - feed in more throttle - and so on. If you feed in too much, well, you left about 10% of pedal for such an occurrence and, at some point, you'll find a happy balance, full power is reached on the asymmetric engine, and, at takeoff speed (and above the appropriate Vmca) you lift off. Since Vmca is predicated on having 5 degrees of bank angle "raising the dead" (inop engine on the high wing) rudder and aileron are coordinated to so as to lift off and fly away in a bank. Of course, the airplane doesn't turn if the rudder deflection is correct. The slip/skid ball is not centered, instead it intentionally splits the index line on the operating engines side. (There is a great article somewhere in my files describing with everything from physics to a yaw string why this is necessary, but I digress.)
Another technique, runway permitting, would be to stay on the ground in an attempt to reach 2-engine Vmca before liftoff (while respecting tire limit speeds) just in case another motor were to cough. Having two suddenly out on the left side (of a Herk) before getting the gear/flaps positioned was a big concern, as they would then have to be cranked.
This has been an interesting discussion. Any of you B-17 gurus have the Pilot's Manual to reference if any 3-engine takeoff procedures are included for it?
Ken
A common technique for the C-130 three engine takeoff is (in short) to hold the brakes and run the two symmetrical engines to max power. Next, bring the other operating engine from idle into the governing range; this is to ensure it's producing positive thrust with any subsequent throttle advance vs. flat blade angle (barn door) drag. Last, put in 90% of full rudder to counter the good engine. Release brakes, initially steering with the nosewheel. Once the rudder comes alive, that nearly full input will start to bite and the airplane will (you hope gently) begin to track off centerline. Feed in a measured amount of throttle to offset the swerve. Accelerate more. As the rudder becomes more effective, it will try to swerve again - feed in more throttle - and so on. If you feed in too much, well, you left about 10% of pedal for such an occurrence and, at some point, you'll find a happy balance, full power is reached on the asymmetric engine, and, at takeoff speed (and above the appropriate Vmca) you lift off. Since Vmca is predicated on having 5 degrees of bank angle "raising the dead" (inop engine on the high wing) rudder and aileron are coordinated to so as to lift off and fly away in a bank. Of course, the airplane doesn't turn if the rudder deflection is correct. The slip/skid ball is not centered, instead it intentionally splits the index line on the operating engines side. (There is a great article somewhere in my files describing with everything from physics to a yaw string why this is necessary, but I digress.)
Another technique, runway permitting, would be to stay on the ground in an attempt to reach 2-engine Vmca before liftoff (while respecting tire limit speeds) just in case another motor were to cough. Having two suddenly out on the left side (of a Herk) before getting the gear/flaps positioned was a big concern, as they would then have to be cranked.
This has been an interesting discussion. Any of you B-17 gurus have the Pilot's Manual to reference if any 3-engine takeoff procedures are included for it?
Ken
Re: b-17 left teterboro on 3 engines last night?
Tue Jun 26, 2012 12:12 am
Ken wrote:This has been an interesting discussion.
Indeed it has, fascinating in fact. Thanks Ken, and the other constructive contributors.
Regards,
Re: b-17 left teterboro on 3 engines last night?
Wed Nov 05, 2014 9:34 am
I was thinking of an analogy regarding engine torque vs rudder authority on takeoff in the AD-5 and I remembered this thread on 3-engine ops and went back to re-read everyone's input. This was a fun thread, so bump.
Ken
Ken
Re: b-17 left teterboro on 3 engines last night?
Wed Nov 05, 2014 12:34 pm
thanks Ken. flame suit on for round 2. 
.
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Re: b-17 left teterboro on 3 engines last night?
Wed Nov 05, 2014 1:25 pm
Three engine take offs are in the manuals for many four engine military airplanes.
When I flew KC-97G (4 eng.) & KC-97L (6 eng.). Both had procedure for take off with a recip feathered.
There was also a procedure to do a taxi "windmill" engine start with an inoperative starter on a recip.
When I flew C-130's there were those same procedures plus a "Buddy" start where a C-130 with inoperative starter would position behind a running C-130. The engine would get going from prop blast and start.
I have heard "war stories" about C-47's taking off at light weight on one engine. If the wind was right and runway long enough I suppose it could be done.
When I flew KC-97G (4 eng.) & KC-97L (6 eng.). Both had procedure for take off with a recip feathered.
There was also a procedure to do a taxi "windmill" engine start with an inoperative starter on a recip.
When I flew C-130's there were those same procedures plus a "Buddy" start where a C-130 with inoperative starter would position behind a running C-130. The engine would get going from prop blast and start.
I have heard "war stories" about C-47's taking off at light weight on one engine. If the wind was right and runway long enough I suppose it could be done.
Re: b-17 left teterboro on 3 engines last night?
Wed Nov 05, 2014 3:44 pm
Not quite the same, but talking about alternate means of starting on the C-130 made me think How much I would love to see a bungee start performed on a C-47.
Re: b-17 left teterboro on 3 engines last night?
Wed Nov 05, 2014 7:45 pm
mustangdriver wrote:bdk wrote:This would be a good Larry Krause question.
Nah, you got to feather two more engines until he gets interested!
POST OF THE DAY! Hands down.LOLOLOL
Re: b-17 left teterboro on 3 engines last night?
Wed Nov 05, 2014 8:49 pm
b29driver wrote:Three engine take offs are in the manuals for many four engine military airplanes.
When I flew KC-97G (4 eng.) & KC-97L (6 eng.). Both had procedure for take off with a recip feathered.
There was also a procedure to do a taxi "windmill" engine start with an inoperative starter on a recip.
When I flew C-130's there were those same procedures plus a "Buddy" start where a C-130 with inoperative starter would position behind a running C-130. The engine would get going from prop blast and start.
I have heard "war stories" about C-47's taking off at light weight on one engine. If the wind was right and runway long enough I suppose it could be done.
An old recollection coming back. I can't remember what aircraft it was, maybe a Blue Angels jet, maybe a Herc (??), but we had an H-60 or two rigged up using the APU's to try and do a huffer start when one of the other aircraft starters went out. It didn't work....not enough air to turn the engine. Had to get a real huffer to do the job.