10/23 Raptor Video

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Jay Kempf

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Cleaning out all channels that had to do with engine oil is key. How is the question without full disassembly of things that don't like to be disassembled to that level. Lots of pressed together assemblies. I guess you could take things apart to the point where you could build a pump loop with filters to run oil through everything just to assess metal in the oil stream. Not going to happen though.
 

231TC

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ECU in "auto mode"? That's a new term to me.
I think it was "idle mode." Sounds like he thinks the engine quitting was similar to when Justin stalled it taxiing at low throttle by not pulling it back to idle when the air conditioner kicked on. He has the ECU programmed to keep it going when the A/C kicks on, but it only does that with the throttle at idle. Going on memory, and didn't get a thorough understanding of what he was talking about at the time, but that's what I gathered.

Found Peter's explanation of idle mode:
 
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PPLOnly

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How is he verifying that these eBay engines are airworthy? $4,500 seems to get you what they claim is ~50,000 mile engine. That is about 1100-1600hrs of runtime. Considering the totally unknown state of these used engines, how many miles they actually have, if the oil was changed, if they were modified or wrecked, I'd think you'd want to overhaul them after purchase.
 

Rataplan

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I really don't think there's any problem with the wing.

Not draining the oil to look for chunks of metal is almost a crime.
Well the force of the impact of the tip results in a much larger force at the root . Web spar and around the attach bolts can be damaged. That is why you should check it.
 

rv6ejguy

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I think it was "idle mode." Sounds like he thinks the engine quitting was similar to when Justin stalled it taxiing at low throttle by not pulling it back to idle when the air conditioner kicked on. He has the ECU programmed to keep it going when the A/C kicks on, but it only does that with the throttle at idle. Going on memory, and didn't get a thorough understanding of what he was talking about at the time, but that's what I gathered.

Found Peter's explanation of idle mode:
You could see and hear in the 2nd last video that the engine was tying up a few seconds before the prop stopped. I mentioned this previously. It didn't slowly and smoothly spool down, it rapidly did as you can see from the rolling shutter effect on the camera.

You can't keep adding more fuel if the engine is starting to tie up. Not what 'idle' control is for. I couldn't tell if the fuel flow was high because of the overspeed or because the ECU was trying to maintain rpm as the engine tightened up but it stopped at 6 gph and the prop didn't move even at 115 knots afterwards. It was tight.
 
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Marc Zeitlin

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And he inadvertently lets on to potential issues with engine supply to match his anticipated orders. "Several currently available" for an out of production, and relatively rare, engine doesn't bode well for when he needs hundreds of these things next year.
Neither PM (nor anyone else) will need five of these, much less "hundreds", in the next year, or ever.
 

Marc Zeitlin

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Go watch that hit on .25 speed on YouTube. He was descending over 1000fpm on impact. The wing and left gear absorbed all of the descent energy.
I did.

PM had arrested essentially all of the descent rate and was floating down the runway when the roll event occurred. As I suggested previously, given the lack of any wing bending evident in the video, the chance that there's any damage to the wing structure (other than the lower fence) is small. It should be inspected, as should the gear (jack the plane up and check for play or movement in the mounting structure, particularly since he's had one failure of the gear mounting structure before) but _IF_ the gear was redesigned correctly for a 10 fps descent rate, it should be fine.
 

Geraldc

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Now would be the time to cover the underside of both wing fences with kevlar to act as rub strips.What can happen will happen again.
 

PPLOnly

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Neither PM (nor anyone else) will need five of these, much less "hundreds", in the next year, or ever.
I suspect people involved with the program read this, and I hope maybe that will get them to stop wasting all of their time developing for an engine you can’t buy anymore unless it’s from some junked car. Automotive diesels are a dead technology in the US, this is a dead end.
 

rv6ejguy

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That 20mg of fuel is explainable. Some offset or minimum fuel got "baked" into tune or tOOne. A simple example is, on SI engines some ECUs have minimum injector open time setting. So, set it to say 2.5ms, every time injector opens it will be for that time or greater, regardless of internal calculation. Sadly I've seen this more than once on SI engines to force an idle.

I've never used Motec diesel ECU, but as a safe guess, that 20mg can be interpreted as minimum fuel target or commanded value once engine is cranking and angular logic is synchronized (knows where crank is in 720 degree cycle).
It's a fault or error in the data logging to register 20mg of fuel with 0 rpm otherwise fuel would be injecting with the engine stopped if true. This could be offsetting the true fuel flows a huge amount, if 20 is really 0 on a max fuel flow of around 95. This might explain why the performance is so anemic- it's making 20+% less hp than the displayed fuel flow would indicate. I haven't seen an ECU which injects this much fuel continuously at 0 rpm.

Not even sure what this mg figure is. For each injector or all 6? Per second? Per minute? I can't correlate any of these numbers so they make sense with the approximate hp being produced at full power which is roughly 1400mg/min.
 
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TFF

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I’m surprised that any of you are surprised. Might not what anyone else would do, but anyone else is not doing this. You all are going to spoil everything if you hint the oil system needs to be cleaned. We can have a third engine on order faster, if if he just bolts on and goes. If everyone keeps wanting the wing inspected, he might do it. Occasionally he reads comments and does them. Next someone will say get rid of the spades. What is to come of this thread if he really came to his senses?
 

PPLOnly

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I’m surprised that any of you are surprised. Might not what anyone else would do, but anyone else is not doing this. You all are going to spoil everything if you hint the oil system needs to be cleaned. We can have a third engine on order faster, if if he just bolts on and goes. If everyone keeps wanting the wing inspected, he might do it. Occasionally he reads comments and does them. Next someone will say get rid of the spades. What is to come of this thread if he really came to his senses?
I don’t want anyone to get hurt. He used up his free pass deadsticking this high speed rock to a successful landing. He really needs to step back and evaluate why he’s doing this testing on an airplane that’s too heavy, doesn’t have a reliable pitot system, doesn’t have a viable Powerplant, and isn’t going into production in its current form. He’s risking his life to gather data he’ll never use. It’s insane.
 

Marc Zeitlin

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I don’t want anyone to get hurt. He used up his free pass deadsticking this high speed rock to a successful landing. He really needs to step back and evaluate why he’s doing this testing on an airplane that’s too heavy, doesn’t have a reliable pitot system, doesn’t have a viable Powerplant, and isn’t going into production in its current form. He’s risking his life to gather data he’ll never use. It’s insane.
Preaching to the choir. You really need to go back and read the 78,456,981 posts in the previous thread, and all of the 1,596 in this one, as well.
 

PPLOnly

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Preaching to the choir. You really need to go back and read the 78,456,981 posts in the previous thread, and all of the 1,596 in this one, as well.
I was more responding to the people that want the YouTube soap opera to continue over PM waking up. He was flying with a oil seal not held in by anything...does he understand how insane that was? I don’t think he doesn’t considering he tried to run the engine with no inspection.
 

Pops

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The longer this go's the crazier it gets.

Think I will just tune out, don't want to see the ending.
 

Dead on Time

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Not even sure what this mg figure is. For each injector or all 6? Per second? Per minute? I can't correlate any of these numbers so they make sense with the approximate hp being produced at full power which is roughly 1400mg/min.
am pretty sure it's 20mg/stroke, that is each injection event.

seem to remember from one of the engine log videos Raptor fuel consumption ~96mg/stroke at full power. Working through the numbers that is ~20.4 gals/hr which is more or less what cockpit indicator reads on Raptor's take-off run.

if however 20mg/stroke indicated is actually zero mg/stroke and therefore full power fuel flow is 76mg/stroke then full power fuel flow is actually 16.15 gals/hr. Assuming a generous bsfc 0.367lbs/hp/hr (same as EPS Flat V diesel at 350hp output) then Raptor engine is making ~305 hp.

Interesting that the cockpit fuel flow indicator read 0 gals/hr after Raptor inflight engine stoppage, yet the engine logs still show 20mg/stroke. Have to wonder how Raptor cockpit fuel flow indicator gets fuel flow information. From the ecu or a fuel flow transducer?

DoT
 

Mike0101

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It's a fault or error in the data logging to register 20mg of fuel with 0 rpm otherwise fuel would be injecting with the engine stopped if true. This could be offsetting the true fuel flows a huge amount, if 20 is really 0 on a max fuel flow of around 95. This might explain why the performance is so anemic- it's making 20+% less hp than the displayed fuel flow would indicate. I haven't seen an ECU which injects this much fuel continuously at 0 rpm.

Not even sure what this mg figure is. For each injector or all 6? Per second? Per minute? I can't correlate any of these numbers so they make sense with the approximate hp being produced at full power which is roughly 1400mg/min.
Well, yes and no.

It really depends on how software is written. Some simple examples are IAT (inlet air temperature), oil pressure, ECT (engine coolant temperature), MAP (manifold absolute pressure)... and so on. Once the ECU starts up, performs sanity checks, and fires up OS, these analog values will be read (via analog to digital converter), transfer functions performed, then appropriate values written to random access memory location specified. This happens regardless if engine is stopped (usually referred to as stalled), cranking, or running. I can't say this is universally true for all ECUs, but I can't think of anything I've worked with that doesn't act like this.

Now, MAP can be both time and crank angle dependent or synchronized (started time based then switches to crank angle burst mode).

As far as reading odd values with engine stopped. A good example is MAF (mass air flow) sensor, it is never truly "Zero" even when within specifications. Mess up transfer function (lookup table), or 2 point calibration with offset, and you can register sufficient mass flow with stopped engine to exceed normal idle state. How do I know, been there done that... Before anybody asks, no I didn't crank with such a large error.

So most OEM ECUs have sanity checks to identify such conditions and revert to a limp mode or simply don't start. But aftermarket ones are far more forgiving. Being forgiving they do need to display and log values, regardless of engine state, windowed (hole in case), stopped, cranking, running.

Now with above being said... Most ECUs will solve about a similar amount of critical code when the engine is running or stopped. They may have alternate cranking lookup tables (most OEMs do). A good SI example is IAT and/or ECT timing retard, you pulled over due to overheating engine, popped the hood, saw nothing, waited a bit, then proceeded to attempt a re-start. That timing is already being pulled via appropriate tables, even before cranking is detected (it is a partial calculation or not complete total timing).

You can have offset of what ever when engine is stalled/stopped. Most modern ECUs are crank angle synchronized with respect to injection and timing (if SI). If memory serves correctly, Motec software state engine, is 3 states - stopped, seeking (motioned detected) and finally synchronized to reluctor wheel and cam (forgot exact verbiage, but can see it while cranking). Once synced, injection pulse width is scheduled with appropriate function/task/or coprocessor. What I described is overly simplistic, far more interlocks and safeties in real life.

The Motec is extremely flexible, you can create custom lookup tables, hardly any hard coded limits, so unfortunately creating garbage is easy too.

20mg error is a 0.020 gram error. Depending on ECU (PCM is GM speak) air is reported in grams, and fuel on per cylinder in milligrams... Add to that, total mass flow is per minute, timing on per event (or per intake stroke)... It changes year to year, model to model.

As mentioned, I have not worked with diesel Motec, have with previous generation SI unit.

Sorry for long winded post, but baked in values or errors can happen, as well as forced offsets (intentional or not).
 
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rv6ejguy

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am pretty sure it's 20mg/stroke, that is each injection event.

seem to remember from one of the engine log videos Raptor fuel consumption ~96mg/stroke at full power. Working through the numbers that is ~20.4 gals/hr which is more or less what cockpit indicator reads on Raptor's take-off run.

if however 20mg/stroke indicated is actually zero mg/stroke and therefore full power fuel flow is 76mg/stroke then full power fuel flow is actually 16.15 gals/hr. Assuming a generous bsfc 0.367lbs/hp/hr (same as EPS Flat V diesel at 350hp output) then Raptor engine is making ~305 hp.

Interesting that the cockpit fuel flow indicator read 0 gals/hr after Raptor inflight engine stoppage, yet the engine logs still show 20mg/stroke. Have to wonder how Raptor cockpit fuel flow indicator gets fuel flow information. From the ecu or a fuel flow transducer?

DoT
Yes, you're right. If we break this down: 3800 rpm = 1900 power pulses X 6 injectors= 11,400 injection events/ min X 96mg= 1094400mg= 1094 g/ min. Call that 1.1 kg or 2.42lb/min x 60= 145 lbs./hr /6.6= 22 gal/hr. and we see around 21 gal/hr. indicated at TO power.

I've used .42 BSFC at high power on Raptor due to the dreadfully restrictive turbo setup.Call that 345hp but we know from the acceleration runs, static thrust and ROC that can't be right. Using 76 mg instead, yeah around 273hp which agrees with other observations better.

No flow transducer as far as I know, just measured from injector pulse width and frequency.
 
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