Personally if I had an engine in an airplane that experienced an oil starvation event I would feel obligated to tear it down. at a minimum I'm hoping that you're going to cut open the oil filter and have the oil analyzed for metal particulate. even though there was some oil pressure they're still a good chance of engine damage.
The pucker factor of having the first dead stick landing in a new airframe be one that wasn't planned has to be beyond description. Glad everything worked out!
Gear down and dead prop at flat pitch, the VSI was indicating well over 1000 fpm. If that engine quits on one of those flat approaches normally done, it going to be very bad for the aircraft and whatever is in the area short of the runway. Perhaps calculating and verifying the best glide speed and angle will allow staying above the deadman's curve.
Peter, I would practice engine out approaches in this aircraft. You've been coming in flat to every landing, and didn't get a good sense of what a power off approach looked like. I command your judgment at adjusting the flight path, and nailing it from first attempt, but this was very close. You touched down before 1000 foot marker in a canard stall. A 2 second miscalculation of the final turn, slightly higher headwind , or warmer temperature, would put you short of the runway. You need to be able to nail these comfortably and consistently every time in different conditions. I would make every approach an engine out for a time being. Great job!👍
+tiverton As a thirty year professional pilot...I fully agree with you. I have flown a number of different types in 30 years...but the one common approach to ALL of them was familiarization with the flight characteristics of each one....and that was with already studying the flight characteristics of each and knowing what to expect. Peter needs to explore and document all of Raptor's parameters...including those same parameters when at the extremes of CG....fore and aft. I know Peter once responded to the question of handling characteristics/stalls by saying it wasn't necessary because Raptor, as a canard, could not be stalled... In my mind I was going...But, but, what about best glide speed? Can you feather the prop? How much is glide improved with a feathered prop? Is it possible to slip a canard aircraft? It's sometimes just as important to lose altitude as it is to maintain...jus saying. My point is ...there are more numbers to be aware of than just stall speed...some of which are also very important....
Peter, it is not so much Normalization of Deviation, as it is "You don't know what you don't know". Intentionally leaving an oil seal retaining ring out can only be explained by the fact that you didn't know any better and believed yourself more knowledgeable than the designer of the re-drive. That is an attitude that that is going to get you killed. You handled the emergency well and got the plane back to the airport in one piece, good job, but it never needed to happen. The engine should be torn down and inspected and then it should go right on a test stand where you can safely explore its performance and reliability. Continued flight testing of the engine at this point is just another example of you don't know what you don't know. You risk the plane you have worked so hard to create and your life as well. Stop and think for a moment where you are. You just survived an inflight emergency of your own creation. You can only run the engine at 60% power without severe overheating. The engine cooling system needs an engineering solution not not a cut and paste solution. The plane is badly over weight and the aerodynamic drag is much higher than you anticipated. It is marginally stable in roll and yaw. Seriously, is that the plane you want to try to put into production? Do you really think you can be successful doing that. Take a break and rethink your plan. You are really trying to do something that is very difficult, and particularly the way you are doing it, so figure out a better way. If you feel compelled to continue flight testing, don't fly it out to California, take the wings and canard off, put it on a trailer and drive it out there, that way you are much more likely to get it there in one piece.
@@afward100 I rather doubt that, but if that is the case, why would the designer not install a lip seal of the correct size and use the retaining ring he felt was necessary for such a critical part? If the designer decided not to do that because he chose to install the wrong size seal and the retaining ring wouldn't fit, why wouldn't he do a simple calculation to make sure that the press fit was more than sufficient to overcome the difference in CTE between the aluminum and steel and resist the delta P across the seal? The designer would also find another way to hold the seal in place regardless of the press fit in a single point failure component. Makes me wonder if the designer calculated the fatigue life on the tapered roller bearings. I don't want to belabor the point and I agree that normalization of deviance is certainly prevalent in the flight test program, but I honestly believe that not knowing what you don't know is fundamentally the issue and that Peter would be much more successful and live longer if he would involve more folks who do know what he doesn't know.
You safe on the ground and that is all that matters. For the future, I would recommend dump that shallow approach. Develop a habit to descend and do base and final with the engine on idle. Very helpful skills.
I would definitely get an oil sample, it tells quite a bit, for $25 it can give you some piece of mind. I would also give it an oil change before you run it on the ground and then give it another oil change to make sure anything would be flushed out. Cheap PM for reassurance,
An oil sample is 100% necessary for something like this. If an engine sees that much oil loss, and that little oil pressure, you have to find out if the engine started making metal.
Absolutely get an oil analysis, Peter...this is some of the best info and insurance you can buy as you go forward. Nice job on staying calm and resolving the emergency positively. -Don
Unbelievable to go flying when obviously important parts are not installed because they were hard to install. Peter please step up your game. I guess professional test pilots would have sorted such issues out before flying. Anyways i am happy no body was hurt. No more botch please many people have said that!
Flat sanding the clip was outside of your todo list? Going forward, adding .015" to .020" to the grove width to accommodate variations of manufactured sub component? You were very lucky my friend! Good luck and be careful Peter
It is unbelievable that you entered a reply on RU-vid with obviously important grammar not installed. MrKillerpics, please step up your game. "Anyways i am happy no body was hurt." Really? This is drivel. As is, "No more botch please many people have said that!" The airman in the video owned up to his mistakes but will you? I doubt it.
@@multa765 u know here around not every one is native in English but according to the answers and thumbs up most people did understand my comment :* cry baby cry Btw: my grammar mistakes do not endanger anyone but a plane w/o functioning engine does
Not sure he needs you to point out the obvious for him.... he clearly regrets not putting the clip in, and your response is jut piling on... GTFO unless you have something constructive and helpful to add.
When I had my own aircraft, I made sure I could always ask a certified A&P mechanic about correct procedures when I was doing my own maintenance. I have to assume that snap rings to hold orings in critical places represent a century of continuous improvement with regard to engine reliability and safety. It's an opportunity to have a A&P go over the engine with you when you get it started.
So happy this turned out as well as it did. Best part is a landing you can walk away from... Having "Blown up" turbo chargers in my race car, if it was me, I would pull both turbos have their center bearing sections re-built for peace of mind. A simple check, first test is to grab the main shaft nut at the impeller and attempt to wiggle it. Pay very close attention, if you can detect any "Play" there is a problem. Since there was suspected "coking" I would never trust that additional wear and week point for the individual bearings. As I stated above, I would have the "center section" on both turbos re-built. They can ensure no coking remains in the bearings, along with uneven bearing wear, along with damage to the actual primary shaft which could cause problems later on. There are many places that perform this service during the service, a competent shop will re-balance the shaft with the impeller, and the exhaust turbine. I hope you'll consider sending both out for rebuild. Happy you and the aircraft are "okay" as can be considering the event, Best regards, Mo-
I'm sure others have said the same, but You must check the engine more thoroughly. Throw a rod right after take-off and You may get wings of your own. Remove sump and check all bearings - rebuild both turbos. This is a bare minumum. Do it! 😷
Richard it also requires re-engineering the entire structure to take the impact then testing to see whether it works. It would likely require several million dollars in destructive testing to make anywhere close to reliable and safe. A better option is to focus on keeping the wings off the ground.
Most modern engines have a mains primary oiling system meaning that the main bearings get oil before anything else does. Pulling the main bearing caps for a bearing inspection might tell you about the lower end, but it tells you nothing about the top end of the engine, which probably was starved for oil at the very least. You have to think about the camshaft, followers/lifters, cam bearings, valve guides, etc. While you might feel comfortable flying it without a complete engine tear down inspection, the fact remains that you are flying out of a public airport and not a designated flight test facility. You have a responsibility to public safety. Imagine if that engine seizes shortly after takeoff and you have to put it down again. You might not have that 8,000 ft. runway the next time. You could end up on a highway, a pasture or worse, possibly someone's back yard. While it might be expensive to remove the engine and perform the tear-down inspection, how expensive could it get if you don't?
Not to mention liability. At this point there is public evidence that something happened and further evidence of a lot of people telling him to do more than he is suggesting he will do. While I love the openness, this is an elevated liability risk since should something happen. Hopefully Peter is right and there is no damage and we are all concerned about nothing.
Peter, nice job on the recovery. That was close. First thing. Turn to the nearest landing surface, climb to get on an emergency engine out glide profile to that surface, make sure the aircraft is clean (later gear extension?), establish best glide speed to the field. Ideally be overhead the landing surface for at least one 360 to land. You made it. Be happy and proud of that. Keep pressing on, we are all cheering for you.
You need to take the pan off and inspect at least one journal or rod To make sure your engine is OK otherwise you will have a catastrophic failure you may think that oil pressure was enough but you need to know that It wouldn’t hurt anyway it would be time consuming but better safe than sorry
Engine oil analysis could suggest whether you should drop the oil pan to inspect the crank bearings and ultimately save money by preventing a top end failure. I'd guess the top end could be inspected right now with a borescope through the oil fill. But really the oil analysis should have been done all along. So maybe that will play into the psychology of not doing it now.
Great job getting it on the ground. Knew it was the redrive seal simply due to the volume of oil. No more oversights ok Peter! Could have had a second relief milled into the redrive housing to have the tolerance you needed to fit the C clamp and saved yourself the heart attack and wing strike. Looks like it stalled wing drop at 78 knots. And good job figuring out your glide in an emergency.
Firstly I’m glad you made it back in one piece. I’m not sure on your theory though. I’ve seen an engine keep running when the turbo seized and a sudden decrease in RPM will give you the slight boost spike aka I’d say the engine seized. Once again I’m dumbfounded that you didn’t fix something simple that could’ve cost you your life. It’s just a the circlip. But it’s a very important job it does.
Did the engine "shut down" or seize? Even seized turbos would still flow enough air for it to at least windmill/idle. Had it happen. Any plain bearing that gets "tight" is basically finished. Especially in a plane. That engine was basically at 4k on 5.5 psi of oil. I would completely take it apart and inspect everything. Not just several random journals. It would be crazy not to. I would have trust issues having that engine on a road trip in a car. Let alone in a single engine plane.
According to the video the turbos slowed down and starved the engine of air. While I would have at least sent an oil sample out for analysis I have to think that the pilot is coming from a more knowledgeable place.
Hopefully Peter will explain the scenario in more detail, but it seemed to me that the redrive lost its oil and seized, causing engine stall. Perhaps there was still sufficient oil in sump to protect motor?
I just want to say: what a great job getting down safely. It’s a bummer that this has happened but having been through dozens of failure reviews and RCCA’s (root cause, corrective action) I can tell you it’s a huge relief to find the root of the issue so easily, even if it could have been prevented. Keep going! I can’t wait to buy one.
Beautiful job! I've had similar, but at night just after takeoff. Mine didn't end quite as well as this, my aircraft was no longer usable and I still deal with injuries I sustained more than 20 years ago. So, GREAT JOB!
I would put a bolted flange in front of the sealer, I don't know if it's possible, but an item like this deserve double or more safety. It can cost a entire airplane.
I was thinking a backing plate, design to keep the seal from popping out, but doing so mean removing part in order to drill retaining holes for screws or bolts to keep the seal in place. Well just a thought base on what I see. I am no mechanic or engineer, but he is good at problem solving too, I am sure he fine a fix and solved the issue.
Oh the tease from the last video. The fact that you have published the engine out means it wasn't catastrophic. Fingers crossed for the next flight and you back in the air soon. Thanks for sharing all the aspects of the development of your aircraft.
From a Couch Pilot: Likely just rwy rash, but some vibrations there after contact. Perhaps check wing root and wing strut mounting points; bore scope internal wing tank for any stress fractures? Now you can add a successful dead-stick landing to your test pilot repertoir. 😬. Just one more thing: perhaps have a custom redrive oil seal/ring made to your exact requirements, if factory seals/rings are not available. Cheers.
I strongly urge you to stop flying your airplane and involve a test pilot and approach this in a more careful and analytical way. You need to fix the things (like over control ability) that you know need work, it isn’t worth your life!
@@charliemonster42 you are probably right, my comment was really directed at Peter, whatever issues he THINKS he has at the very minimum should be corrected but he is writing it off as “well it’s a prototype so it will have issues”. I’m genuinely concerned for this guys life and the irreparable harm he will do to the experimental aviation industry when he wads this thing up.
Glad that ended as well as it did! Good call on declaring the emergency, it most certainly was!! Take the time to have an oil analysis done, the turbos could both be toast. They don’t respond to oil coaking well at all. Additionally the valve guides and cam bearings could be fatigued from starvation. Very glad you are ok!
If you haven't already drained the remaining oil from the sump, I'd highly recommend getting an analysis done on that oil just to check that you haven't got any obvious damage to the engine that would show up in the oil.
@@jessegunderson2605 This is why i skim through the comments and ignore most of them. This isn't the first time people raise concerns (for some nefarious purpose?) on items that the poster would have known if, ya know, they actually watched the video.
@@tread140 Yup, I'm with you. Also, people assume that if you don't mention it in a 20 minute clip, that you must not be doing it. I think most of us know that even if you don't mention something, there's a lot of hours in the day and I always assume you're doing shit in the other 23.5 hours remaining :)
Very thankful you’re safe on the ground. You should be able to have a steel retainer surface ground to fit the space you have for the retainer. Hope all goes well.
Hmmm hearing the sounds in the last moments i'm afraid the damage is already done:( but idk Let's see what comes out when the remaining oil is drained.
Well, that was a bad thing to have happened but I'm glad you made it back ok. And the plane is basically in one piece, so that's another silver lining. Still rooting for you!
I strongly recommend you do not just "trim off" the damaged part of the wing that hit the ground. I have some experience with fiberglass and carbon fiber - manufacturing and repair. It needs to be properly repaired. Air pressure can and will fully separate the carbon layers and eventually destroy that area of carbon fiber. I used to race an Olympic class catamaran called the Tornado - 20+ knots. One time the starboard rudder destroyed itself while sailing - there was a small crack in the leading edge of the rudder. Water pressure caused that crack to grow. Eventually, the two halves of the rudder separated and I lost the starboard rudder entirely. Please repair that carbon fiber! So glad you kept your cool and flew the aircraft.
Glad your safe and well good job with the deadstick. hope the engine is ok must say i was worried seeing the boost spike as that can also be caused by rpm decaying quickly ie something getting tight however the log didnt seem to show rapid rpm decay at that time. So Happy the result was good and minimal damage. a real nail biter Pete.
@@lacantinadicrono798 He had to control energy all the way down (when to lower gear, flaps, slipping, etc) to arrive at TD in the landing zone. Sure he could have shot for further down the runway and maybe not be able to stop. Any landing you walk away from is a good landing, and any landing that you can still fly the airplane again is a great landing! Zero energy only occurs after a full stop, IMHO. Peter made a GREAT landing!
It's those little minor things, you don't do wind up being major things that can cause tragedy, in the end, I'm glad you caught the mistake and corrected it most pilots don't and they are no longer here.
A thought for future development of your engine/re-drive combo.... Your re-drive loosing oil meant your engine lost oil, not sure if there is a relatively simple pressure/check valve that if too much pressure is lost the re-drive oil supply is cut off. You mentioned if you pulled the prop back to flat pitch that would not apply any additional power to the governor, and that sounds like a good sensible engine failure procedure for you to add to your manual. With the automation you have onboard, is it possible to codify that behavior (possibly with a manual override)? Lastly, if you are able to contain issues in your re-drive to not affect the engine, be it a cut off, or a different oil loop, it might be a good (obviously future) R&D stream to look at how long, and what you can do, to run oilless in the re-drive (with bushings or other solutions), to extend your window to RTB under power (i.e. rather buy a new re-drive than a new aircraft!). I immediately thought of the S92 crashes from oil failures in the gearbox when you showed the seal popping out. Obviously keep up with making the simple solutions first that increase safety before any (over) engineering projects.
Have the oil tested and then keep testing it every oil change untill you are satisfied that there is no accelerated wear. My point is to do some to check the engine in some way. Also you could get the circlip surface ground to suit
Take your time analyzing the cause, it may not be what it seems. My gut says a stalled (turbo)compressor should let enough air pass to at least keep the engine running. Stay safe and act smart, from an engineer and fellow pilot.
@@rv6ejguy I would expect black or even white exhaust smoke if there is not enough air. Unless it's the ECU that is also cutting fuel, that would not be very fail-safe. I know problems are often misidentified (especially by commenters just like me), so care must be taken before assumptions are made.
Hi Peter sorry to hear about that, real bad luck. Very much hope this is not too bad a fix. Agree with your thoughts should this repeats in the future, oil seals in this position must always have a retainer, was disappointed with your previous discussion, but.i understand your thinking. Hope you enjoy your trip to Osh, all the best. M
Another consideration is to run the governor oil system stand alone. Adding a header tank and electric pump, and remaking a couple of hoses and you have it done given the scavenge is already working. It would need its own oil cooler.
I would look at the wing structure very closely after the contact with that rake. It is impossible to know just how much energy dissipated into the wing and where there might be hidden damage without a thorough inspection.
Ouch! I did not consider that. Not sure or the ramifications of that, but my assumption is that it probably is not good. If the ailerons are overly sensitive like he was saying, he might want to address that as well. All this is cause for concern in my book.
Relieved you're ok but can't believe you knowingly left an engineered component out of the drive train, this is an aircraft not an old paddock basher, tut tut !
Interesting set of events. Several good lessons to learn. And nobody got hurt. A great day for learning. Question: Is it difficult to drop the sump, with the engine insitu, in frame ? It would be nice to see the Big-Ends & Mains, just in case. Cut the oil-filter up, just to check for wear-metals, etc.. I suspect that you are correct, regarding the damage being limited to the Turbos, but obviously do full ground testing (of engine) again before taking her up again. Good excuse for New Oil & Filter. Enjoy living, to fly another day.
on race car engines and gearboxes with similar poping out seal issues, a common fix is a screwed-on mechanical hold from the outside, and it seems you would have the room for such a fix (like a large washer with a couple holes for screws to hold it in place)... some people only use the screws, but this is just a few point stops, then, not the whole periphery.
I’m happy to see you’re safe. As for the turbos I would get them checked by a pro. My experience with turbos I cars is that they are very fragile and the tolerance is very tight. It isn’t an expensive thing to get them checked out and you will feel safe. In cars you can roll the dice but in an airplane it’s not a good idea. Just a thought! I hope there’s no extensive damage to the engine or turbos.
Agreed. One of the key advantages of using an automotive engine is that replacement parts and expertise are easier to come by... Getting a second set of turbos wouldn't be a huge expense, nor would getting them looked at by a race shop.
@@jeffreygoyer7760 You’re 100% correct! My guess is that low oil pressure and cooling in the turbos caused the turbos to jam. Just because they turn when cold doesn’t mean they actually work. For some reason the engine stoped when the oil was draining. I bet most bearings in the engine was affected, especially at the high rpm.
So perhaps worth considering - did some other factor cause an unexpectedly high pressure in the re-drive. For example, what would happen if the recently installed scavenge pump were to fail? I'm not familiar with the type of pump used, but would it provide free flow during failure or would it have basically plugged the drain? Certainly looking like there is some opportunities for improvements in the next revision of the redrive.
You might want to monitor crankcase pressure. Many seals have blown due to crankcase pressure usually because crankcase venting not proper or later at high levels freezing and blocking .
One thing I would recommend is that you calculate and test the best Lift/Drag speed for the aircraft with no engine. That should the first action in emergency, setting that speed. It looked like at 120knots, it was indicating 1,000 ft/min = 12:1 L/D therefore from 4,000' you should have been able to reach 8 nms track distance (12:1 = 6000' = 12 nms. 4,000'/6,000 = 2/3 of 12 = 8 nms.)
This is what I have been saying. The diesel is hotter because of the higher compression required for combustion. Need very high quality seals and vent on left and right of airfoil. Tougher maintenance schedules and higher quality stronger fasteners and gaskets will required.
I would suggest carefully checking the wing tip and spar for delamination as the deflection was significant in the video. Idle turbo’s will not block enough flow to shut down an engine. It is more likely to be friction in the main bearings or elsewhere. I would recommend tearing the engine down for a full inspection or replacing it. Happy to help with another round of GoFundMe funding, etc. Glad you made it back safe.
Does the seal not fit behind the slot because of a tolerance stack up? I wonder if you can start the ring and then use a big tube that just fits in the housing and press it all down together, it would compress the seal and allow the ring to pop into the slot.
Well done, your pilot skills are excellent but I do question the lack of redundancy in this system and as someone with many years of mechanical experience I do worry for you.
Peter how much air speed is needed to spin the prop at flat pitch? You were at 104kts when the prop stopped, and up to 115kts on your decent. If the flat pitch prop will spin at 104kts then something else stopped the prop from spinning, maybe bearings? In the case where you need to lose altitude quickly, can your two wing tip rudders be used as air brakes? This might be a good time to do a tear down inspection of the engine and a condition inspection of the overall airframe. Just to make sure everything is wearing as it should and that no delamination's have developed of the carbon fiber and associated components. Might be a good time to repair the window and make the cabin air tight for pressurized cabin testing.
Perhaps consider setting that end cover up on a machining center and taking 0.1mm off the end seat of the seal recess. Perhaps the previous seal was set in with loc title, as to why it was though to get out.
8 PSI oil pressure or 8 PSI air/oil mist pressure. A lot of that one quart of oil in the sump was probably on the walls of the block when the engine was turning and not at the oil pump input screen.
