B17 crash, more info

Sounds like #3 and #4 weren't producing power, a tough situation.
 
More questions to ponder.
 
Can a B17 actually maintain controlled flight with 3 and 4 out?
 
Rein Hart said:
that was with higher octane fuel producing more hp though.
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True. But this would be more of a control than thrust issue, I’d think. They are much more lightly loaded too.
 
I read somewhere that the waste gates on the turbo/super chargers are welded open on these airplanes to prevent detonation because they are being run on 100ll and not the original spec fuel. If this is true then those engines probably make no where near their original horsepower. Does anyone know if this is true?
 
PaulS said:
I read somewhere that the waste gates on the turbo/super chargers are welded open on these airplanes to prevent detonation because they are being run on 100ll and not the original spec fuel. If this is true then those engines probably make no where near their original horsepower. Does anyone know if this is true?
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Those engines were spec'd for anything from 87 octane (which was what was available when the first B-17's flew) up to the high octane stuff the big iron used into the '70's. Obviously, you can't run as much boost with 87 or 100 octane as with the 140 (?) octane or with 100/130, but WWII was mostly fought running 100 octane fuel. The really high octane stuff was for the fighters to eke out the last few MPH. On bombers, they were a little more concerned with engine longevity than to push them that hard.

As I understand it, the turbos on the Collings (and EAA and...) B-17's are not used. I don't know what plumbing changes were made to do that. But I imagine (don't know) that the engines they were using had integral superchargers (like the R-1820's on DC-3's and C-47's do) to provide some level of additional boost. Looking at DC-3 power charts I found online, it appears that you could probably run 38-40" of MP in these engines with 100LL, and at 2700 rpm, you'd have ~1,000 HP engines. I would consider this directional, rather than precise information.

There's gotta be someone around here with the experience to share the actual numbers.
 
kyleb said:
Those engines were spec'd for anything from 87 octane (which was what was available when the first B-17's flew) up to the high octane stuff the big iron used into the '70's. Obviously, you can't run as much boost with 87 or 100 octane as with the 140 (?) octane or with 100/130, but WWII was mostly fought running 100 octane fuel. The really high octane stuff was for the fighters to eke out the last few MPH. On bombers, they were a little more concerned with engine longevity than to push them that hard.

As I understand it, the turbos on the Collings (and EAA and...) B-17's are not used. I don't know what plumbing changes were made to do that. But I imagine (don't know) that the engines they were using had integral superchargers (like the R-1820's on DC-3's and C-47's do) to provide some level of additional boost. Looking at DC-3 power charts I found online, it appears that you could probably run 38-40" of MP in these engines with 100LL, and at 2700 rpm, you'd have ~1,000 HP engines. I would consider this directional, rather than precise information.

There's gotta be someone around here with the experience to share the actual numbers.
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I was crouched in a B-25 cockpit last Sunday asking the pilot questions. It used to run high octane but due to the current 100ll it has reduced performance so the crew changed their take off procedure as a result. So certain bombers did run higher octane in the past versus today.
 
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Rein Hart said:
I was crouched in a B-25 cockpit last Sunday asking the pilot questions. It used to run high octane but due to the current 100ll it has reduced performance so the crew changed their take off procedure as a result. So certain bombers did run higher octane in the past versus today.
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Yes. I said that. The part about "the high octane stuff that the big iron used into the '70's".
 
PaulS said:
I read somewhere that the waste gates on the turbo/super chargers are welded open on these airplanes to prevent detonation because they are being run on 100ll and not the original spec fuel. If this is true then those engines probably make no where near their original horsepower. Does anyone know if this is true?
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My understanding was they had the wategates wired to make maintenance cost lower and give additional detonation margins. But mainly just not using full power because they don’t need it for such light weights and engines last longer.

Not a fact. Just the rumor I heard years ago.
 
Someone is n this board has worked on the 909 and they confirmed the wastegate on the turbo is welded open.

If you read the report it sounds like they were losing altitude and could no hold it.
 
Jamie Kirk said:
Someone is n this board has worked on the 909 and they confirmed the wastegate on the turbo is welded open.

If you read the report it sounds like they were losing altitude and could no hold it.
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Couldn’t hold it AND simultaneously maintain directional control...
 
I don’t know if they knew what they were talking about, but the fuel crew at our airport said that the B17 was misfueled. IOW jet A.
 
Okay, thanks Peter. It seemed that our fuel guys didn’t have much to back up what they were saying, but I’m glad they’re conscientious about it.
 
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b-17%20bomber_1570313355575.jpg_16510818_ver1.0_1280_720.jpg
 
MBDiagMan said:
I don’t know if they knew what they were talking about, but the fuel crew at our airport said that the B17 was misfueled. IOW jet A.
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NTSB FAA and Philips cleared 100LL Truck 14 and it was put back into service I believe two days after the incident.

Collins like everyother warbird I've worked with fuels their own aircraft. You merely hand them the hose and write down the numbers.
 
Tarheelpilot said:
My understanding was they had the wategates wired to make maintenance cost lower and give additional detonation margins. But mainly just not using full power because they don’t need it for such light weights and engines last longer.

Not a fact. Just the rumor I heard years ago.
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Caveat: I’ve never flown a B-17, but I have flown Wright 1820 powered DC-3s.

My understanding of the turbos on the B-17 was to achieve the performance needed to operate in the flight levels. The supercharger will achieve greater than field MP like a turbo will, but will still lose power with altitude. A turbo added to the supercharger reduces that loss.

Similar to the high blower settings in B-25s. Many B-25 operators for example have removed or locked out the high blower/(second stage supercharger) because it serves no useful purpose for what these planes do today.
 
Fearless Tower said:
Caveat: I’ve never flown a B-17, but I have flown Wright 1820 powered DC-3s.

My understanding of the turbos on the B-17 was to achieve the performance needed to operate in the flight levels. The supercharger will achieve greater than field MP like a turbo will, but will still lose power with altitude. A turbo added to the supercharger reduces that loss.

Similar to the high blower settings in B-25s. Many B-25 operators for example have removed or locked out the high blower/(second stage supercharger) because it serves no useful purpose for what these planes do today.
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That is my understanding as well. The turbos being functional would not have improved the performance at low altitude like they were at.

Maybe you can answer this question for me. What octane fuel were these engines meant to run on? Some of the things I saw when searching suggested that 100 should be adequate. Admittedly, I haven’t looked at the TCDS to confirm that.
 
mondtster said:
Maybe you can answer this question for me. What octane fuel were these engines meant to run on? Some of the things I saw when searching suggested that 100 should be adequate. Admittedly, I haven’t looked at the TCDS to confirm that.
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These engines were all originally designed to run on 80/87. Now, I am no fuel expert so I can’t even begin to explain how performance would change with 100 LL
 
mondtster said:
What octane fuel were these engines meant to run on?
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It's my understanding it depended on the dash number of the engine what the certified minimum octane rating was. However, I believe there was a engine power limitation on the use of that minimum octane rating. Most were 80/87 but some were at 115/145 for full power ratings.
 
Bell206 said:
It's my understanding it depended on the dash number of the engine what the certified minimum octane rating was. However, I believe there was a engine power limitation on the use of that minimum octane rating. Most were 80/87 but some were at 115/145 for full power ratings.
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That’s why I asked. I don’t know what version engine is on the B-17 so I was hoping someone a little more connected to that part of Aviation could answer it for me.
 
Armchair quarterback here and will say the hard stuff people want to hear. I know, none of us were there and the PIC made the calls but this report shows many errors made in the accident chain.
Not declaring an emergency and trying to save the plane on MULTIPLE occasions. You were down, dragging wind and tried to accelerate to takeoff and clear an obstacle....
 
Jamie Kirk said:
Armchair quarterback here and will say the hard stuff people want to hear. I know, none of us were there and the PIC made the calls but this report shows many errors made in the accident chain.
Not declaring an emergency and trying to save the plane on MULTIPLE occasions. You were down, dragging wind and tried to accelerate to takeoff and clear an obstacle....
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I'll go even further, this operation, probably, and this airplane, in particular, was an accident looking for a place to happen. The chain for this accident started long before the accident day. We as pilots need to be much better.
 
PaulS said:
I'll go even further, this operation, probably, and this airplane, in particular, was an accident looking for a place to happen. The chain for this accident started long before the accident day. We as pilots need to be much better.
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Yup, no safety briefing? Multiple people saying they were told NOT to tighten their belts because they fail? This was not a freak unfortunate situation, this was gross negligence made worse by horrible neglect.
 
Jamie Kirk said:
Yup, no safety briefing? Multiple people saying they were told NOT to tighten their belts because they fail? This was not a freak unfortunate situation, this was gross negligence made worse by horrible neglect.
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I don't think these were/are bad people, I just think that willingness to accept small issues eventually do people in as the line of what is accepted moves further and further from what is actually acceptable.

I saw this airplane a few days before this tragic crash and almost bought a ticket to fly in it that day, I was horrified when I read the corners they had been cutting to keep that bird flying. Totally unacceptable.
 
PaulS said:
I don't think these were/are bad people, I just think that willingness to accept small issues eventually do people in as the line of what is accepted moves further and further from what is actually acceptable.

I saw this airplane a few days before this tragic crash and almost bought a ticket to fly in it that day, I was horrified when I read the corners they had been cutting to keep that bird flying. Totally unacceptable.
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That's the problem, and IMO makes them bad people. The pilot was also in charge of the maintenance, he knew the corners being cut over and over. If you want to do that in your plane without putting others at risk that is your prerogative. But to do that, continually over and over with people who unknowingly knew the corners being cut. Should be criminal.
 
Jamie Kirk said:
That's the problem, and IMO makes them bad people. The pilot was also in charge of the maintenance, he knew the corners being cut over and over. If you want to do that in your plane without putting others at risk that is your prerogative. But to do that, continually over and over with people who unknowingly knew the corners being cut. Should be criminal.
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I hate it when I unknowingly knew things. :)
 
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