Raptor Aircraft

Datadriver said:
I don't recall him ever establishing that during the many flights prior to the emergency
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It does seem that glide characteristics would have been part of the calculated aerodynamics that he has based his performance expectations on, so even without a test he should have had some guesstimate of the glide speed and ratio.
 
Blames the poor landing on control sensitivity. :rolleyes: No, you were in panic mode and rolled in 15 degrees of bank at the last second because of that. If the controls are that sensitive and the aileron spades have relaxed the forces that much, maybe it’s time to rethink the flight control setup???
 
He's fortunate he stayed close to the air field. This could have had a very different outcome.
 
jsstevens said:
Yeah, I heard what he said. I was hoping somebody who actually knows says something.

Enough acetone and it'll be fine. (I wonder what the oil seals in the turbos are made of? Something acetone might dissolve or weaken? Maybe?)
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Journal bearing turbos are often a good early warning device for how bad the engine is messed up. They’re also a great source of metal that will find its way into every oil gallery and bearing when they fail. But, sometimes you win and sometimes you lose. Modern engines and turbos seem far more prone to sending metal everywhere when they fail than the old stuff was.

Generally speaking, seals in a turbo are not seals like a crank seal would be. They’re metal sealing rings, more like what you’d find in an automatic transmission.
 
wayne said:
At this point? Something slightly better than the Space Shuttle.
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My napkin math may be off, but if he's losing 1,500 fpm at 100 knots doesn't that work out to about 6.5:1? I think the shuttle on approach had 4.5:1
 
Omalley1537 said:
It did.

The only bone I’ll throw PM here is that my Cummins Ram would darken the oil within a couple minutes of an oil change. No idea if the Audi is similar.

edit:I see it was addressed above. On the Cummins, (5.9 common rail) it was emission equipment that did it. I haven’t looked but I’m guessing PM removed some or all of that for the application.
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Ditto with a pair of Detroit Diesel 6V53's in marine service. These engines were run at full power for hours on end, and had over 4000 hours on them...

-Skip
 
jsstevens said:
Given his explanation for why the engine shut down (the turbos got so hot they coked the oil and stopped turning), what are the odds that the turbos are damaged?
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i’m not buying his explanation as to why the engine shut down. If that happened he should’ve seen his EGT going through the roof. It’s also my experience that the engine should continue to run just fine to a certain point. With a siezed turbo it certainly will not be creating the power though.

Modern diesels that I’ve been messing with need high pressure oil to fire the injectors. When you lose that oil supply the injectors quit firing.
 
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Bacho said:
i’m not buying his explanation as to why the engine shut down. If that happened he should’ve seen his EGT going through the roof. It’s also my experience that the engine should continue to run just fine to a certain point. With a siezed turbo it certainly will not be creating the power though.

Modern diesels that I’ve been messing with need high pressure oil to fire the injectors. When you lose that oil supply the injectors quit firing.
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Yup. Low oil level will starve the Low-pressure oil pump, which then keeps the high-pressure oil pump from feeding the fuel injectors. Low/no oil means dead engine. Consequently, the HPOP pressures tend to have shearing effects on motor oil which break it down faster than a typical gasoline engine. One reason why oil changes on modern diesels are much more important than on the gasoline engines.
 
Velocity173 said:
Oil is awfully dark.
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I think that may be a diesel thing. Not certain but a 50hp boat diesel that I am familiar with always has completely black oil, even very shortly after a change.
 
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This dude needs an intervention. Gotta know when to throw in the towel man. Surely by now he has to realize at this point his is only further developing his own toy and that nobody in their right mind would buy this contraption.
 
Bacho said:
i’m not buying his explanation as to why the engine shut down. If that happened he should’ve seen his EGT going through the roof. It’s also my experience that the engine should continue to run just fine to a certain point. With a siezed turbo it certainly will not be creating the power though.

Modern diesels that I’ve been messing with need high pressure oil to fire the injectors. When you lose that oil supply the injectors quit firing.
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If you’re messing with something that uses high pressure oil to drive the injectors, it isn’t modern. ;)

The Audi would be using what almost all the manufacturers are doing now which is high pressure common rail injection.

I agree, a diesel will run a long time with extremely high exhaust temps. Along with the other durability tests I am part of at work, sustained high EGT testing is one of them. The truck and tractor pulling guys will bury a 2000 degree pyrometer in a hurry and the components take it.
 
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Historically diesels run rich to produce more power while staying cool, which results in black soot, which quickly darkens the oil. That rich mixture is what causes the thick black smoke you see tractor pullers and bro-dozers belching out.

Modern emission controls have changed that. My 2013 tractor is tuned to run leaner & hotter, which eliminates the soot, but produces more NOx. This is treated in the exhaust with DEF and converted to N2 and H2O. It has a 600 hour oil change interval (compared to 150-200 for older equipment), and the oil still looks like new up to around 4-500. Pretty much all the newer stuff in the last decade has fully electronic fuel injection, the hydraulic-electric systems were a late 90's early 2000's thing. And they sucked.

I haven't been watching the videos, so i don't know how old his engine is, but i assume it's running an aftermarket ecu and is not tuned like it left the factory. Does(did) it make any smoke when he goes full power?
 
GaryM said:
If so, his performance expectations don't instill a lot of confidence on the calculated aerodynamics.
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He was dragging a windmilling prop in flat pitch for a lot of that. Can't help.
 
Velocity173 said:
Blames the poor landing on control sensitivity. :rolleyes: No, you were in panic mode and rolled in 15 degrees of bank at the last second because of that. If the controls are that sensitive and the aileron spades have relaxed the forces that much, maybe it’s time to rethink the flight control setup???
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To me it seemed like he dumped the gear way sooner than he should have. When he finally crossed the threshold he was doing what, 85 knots? Lagging authority at slow speed? He could have held the gear up a good 30 seconds before he did and would have given him more energy. Its not like he needed all of the runway.
 
iamtheari said:
It does seem that glide characteristics would have been part of the calculated aerodynamics that he has based his performance expectations on, so even without a test he should have had some guesstimate of the glide speed and ratio.
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I imagine that they are shuttle-esque.
 
Jim K said:
Historically diesels run rich to produce more power while staying cool, which results in black soot, which quickly darkens the oil. That rich mixture is what causes the thick black smoke you see tractor pullers and bro-dozers belching out.

Modern emission controls have changed that. My 2013 tractor is tuned to run leaner & hotter, which eliminates the soot, but produces more NOx. This is treated in the exhaust with DEF and converted to N2 and H2O. It has a 600 hour oil change interval (compared to 150-200 for older equipment), and the oil still looks like new up to around 4-500. Pretty much all the newer stuff in the last decade has fully electronic fuel injection, the hydraulic-electric systems were a late 90's early 2000's thing. And they sucked.

I haven't been watching the videos, so i don't know how old his engine is, but i assume it's running an aftermarket ecu and is not tuned like it left the factory. Does(did) it make any smoke when he goes full power?
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Every once in a while you'd see a little soot in the exhaust. You're obviously more in tune with Diesel implements than I. But I thought our skid steer was a 2014 (maybe it's a 2012) cant remember that far back and was interim tier 4. No def. That's one reason we got it when we did. Bobcat was, and still does have problems with biodiesel gelling on the tier4 final engines. Oil is black pretty quickly. Just thought it was the nature of the beast. Interesting emissions has cleaned up the oil as well.
 
Jim K said:
Historically diesels run rich to produce more power while staying cool, which results in black soot, which quickly darkens the oil. That rich mixture is what causes the thick black smoke you see tractor pullers and bro-dozers belching out.

Modern emission controls have changed that. My 2013 tractor is tuned to run leaner & hotter, which eliminates the soot, but produces more NOx. This is treated in the exhaust with DEF and converted to N2 and H2O. It has a 600 hour oil change interval (compared to 150-200 for older equipment), and the oil still looks like new up to around 4-500. Pretty much all the newer stuff in the last decade has fully electronic fuel injection, the hydraulic-electric systems were a late 90's early 2000's thing. And they sucked.

I haven't been watching the videos, so i don't know how old his engine is, but i assume it's running an aftermarket ecu and is not tuned like it left the factory. Does(did) it make any smoke when he goes full power?
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There are a few reasons smoke is created but visible smoke will start while the mixture is still quite lean and as you note, additional power is produced way beyond that threshold. When it comes to emissions compliance, the implementation of DEF was a good thing because it helps scrub a lot of emissions that were previously a challenge to control. The calibrations can now go back to offering more performance and fuel efficiency than was possible without it. Unfortunately it comes at the expense of the operator as it is another consumable fluid that needs to be bought and the emissions equipment doesn't last forever.

From what I've seen, the biggest contributor to soot loading the oil is the in cylinder dosing that is commonly used to heat the aftertreatment. EGR doesn't seem to help either. Shut both of those off and the oil tends to clear up quickly and stay that way.

I really don't care enough about this project to watch all the videos either but it seems that he is running an ECU that has tuning support. One of the really nice things about using a European engine is that there seems to be a lot more interest and support for real tuning work than there is for the US built stuff.
 
Racerx said:
Every once in a while you'd see a little soot in the exhaust. You're obviously more in tune with Diesel implements than I. But I thought our skid steer was a 2014 (maybe it's a 2012) cant remember that far back and was interim tier 4. No def. That's one reason we got it when we did. Bobcat was, and still does have problems with biodiesel gelling on the tier4 final engines. Oil is black pretty quickly. Just thought it was the nature of the beast. Interesting emissions has cleaned up the oil as well.
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The break point for DEF or not depends on horsepower. Anything under 75hp still does not require it.
 
mondtster said:
There are a few reasons smoke is created but visible smoke will start while the mixture is still quite lean and as you note, additional power is produced way beyond that threshold. When it comes to emissions compliance, the implementation of DEF was a good thing because it helps scrub a lot of emissions that were previously a challenge to control. The calibrations can now go back to offering more performance and fuel efficiency than was possible without it. Unfortunately it comes at the expense of the operator as it is another consumable fluid that needs to be bought and the emissions equipment doesn't last forever.

From what I've seen, the biggest contributor to soot loading the oil is the in cylinder dosing that is commonly used to heat the aftertreatment. EGR doesn't seem to help either. Shut both of those off and the oil tends to clear up quickly and stay that way.

I really don't care enough about this project to watch all the videos either but it seems that he is running an ECU that has tuning support. One of the really nice things about using a European engine is that there seems to be a lot more interest and support for real tuning work than there is for the US built stuff.
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Interesting about the EGR. My '03 6.0L Powerstroke is deleted and the oil doesn't seem to get particularly black even after 2-3K miles. I also intentionally wanted a pre-DEF/DPF truck to avoid the headaches. A clogged DPF is an expensive ordeal on modern diesels. Sure the exhaust comes out cleaner, but man I'd hate to be dropping $$$ on what is essentially an air filter for the exhaust.
 
In the marine world we used to set the pitch on the props such that it would just *not* make black smoke at WOT.. black smoke = too course.. of course this was on sailboats with auto feathering props and 30 - 75 hp

Oil was always black
 
jsstevens said:
He was dragging a windmilling prop in flat pitch for a lot of that. Can't help.
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I know the fail safe on SE planes is for "blue knob full forward" since that's the best power setting. In twins it's opposite. Granted, in the POHs I've seen they're all written as "windmilling prop" for the glide ratio.. presumably these are mathematically derived figures

Back in the genesis of this plane the design work seemed more competent, so presumably there's record of a best glide ratio/speed somewhere on hand

I will give it to PM, I'm not sure when he practiced his last deadstick landing but that wasn't too bad. He struck the wing but kept it on the runway, walked away, and will undoubtedly use the plane again
 
SoonerAviator said:
Interesting about the EGR. My '03 6.0L Powerstroke is deleted and the oil doesn't seem to get particularly black even after 2-3K miles. I also intentionally wanted a pre-DEF/DPF truck to avoid the headaches. A clogged DPF is an expensive ordeal on modern diesels. Sure the exhaust comes out cleaner, but man I'd hate to be dropping $$$ on what is essentially an air filter for the exhaust.
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That's why I deleted mine when it finally went at 120k miles. Dropping $1500 on a used one of questionable milesage on ebay is insane, let alone the highway robbery of $3k+ for a new factory one. If someone would produce an aftermarket one for the 6.7PSD's I'd be all over it.
 
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SoonerAviator said:
Interesting about the EGR. My '03 6.0L Powerstroke is deleted and the oil doesn't seem to get particularly black even after 2-3K miles. I also intentionally wanted a pre-DEF/DPF truck to avoid the headaches. A clogged DPF is an expensive ordeal on modern diesels. Sure the exhaust comes out cleaner, but man I'd hate to be dropping $$$ on what is essentially an air filter for the exhaust.
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I didn’t see a ton of difference in the oil running EGR vs. no EGR on my old 6.0. It always kept the oil pretty clean. There is a huge difference in the newer Ford engines when they are run with vs. without aftertreatment and EGR.

There are a lot of variables to how/why the oil gets dark and how long it takes. In many cases it is not all calibration related.
 
donjohnston said:
Not necessarily. With the air moving around that engine compartment, even a 1/4 cup of oil could cover almost every surface in that engine compartment making finding the source rather difficult.
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Yes, a small volume leak is harder to find. I figured it would be obvious because it was such a large volume that it must be a big hole somewhere

We were both right, though...oil sprayed everywhere, so the oil coming from forward was misleading as suspected it might be.
 
Didn't watch the video, what ended up having the leak? I gathered a bad seal, but on what?
 
Sierra_Hotel said:
Didn't watch the video, what ended up having the leak? I gathered a bad seal, but on what?
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He admitted to leaving the support ring out on purpose thinking, and I quote, "that's not going anywhere"
 
Grum.Man said:
This dude needs an intervention. Gotta know when to throw in the towel man. Surely by now he has to realize at this point his is only further developing his own toy and that nobody in their right mind would buy this contraption.
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Youtube comments say otherwise
 
Racerx said:
You know, I'll give it to him. He owned up to a mistake and an oversight. It's a start.
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That's right, he started that section of the video with "normalization of deviance"
 
FastEddieB said:
O-ring on the redrive?
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Do I get at least partial credit?

To be honest, I was visualizing a larger-diameter unsupported o-ring that had been flattening out, maybe on the other end of the redrive? I think it wasn’t even originally of the high-temp variety. Then again, I’m a little fuzzy on the design and workings of the redrive anyway.
 
My prediction is the raptor will not fly for at least 6 months. He will put in the new seal, start up the engine and discover his bearings are shot. Then the real issue begins. Where the hell is he going to get another engine? The engine is out of production. My bet is the engine will be replaced with an aircraft engine so he can continue "testing".
 
pilotrick said:
[...] My bet is the engine will be replaced with an aircraft engine so he can continue "testing".
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I doubt it as this would create an entire set of new issues, e. g. with CG and cooling. I would also be surprised if he had the funds to do that.

My bet is that he will either pour fresh oil in and fly it as it is or, at the very best, get another Audi Diesel engine from the junk yard.
 
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pilotrick said:
My prediction is the raptor will not fly for at least 6 months. He will put in the new seal, start up the engine and discover his bearings are shot. Then the real issue begins. Where the hell is he going to get another engine? The engine is out of production. My bet is the engine will be replaced with an aircraft engine so he can continue "testing".
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They're readily available from automotive recyclers.
 
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