Raptor Aircraft

I don’t get what extra coolant is going to do for him. He needs a remote oil cooler more than anything.
 
Why doesn't he just raise the redline for the oil and coolant temperatures? That would solve* the overheating problem without adding weight.

* - No less than his current plan.
 
iamtheari said:
Why doesn't he just raise the redline for the oil and coolant temperatures? That would solve* the overheating problem without adding weight.

* - No less than his current plan.
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A legend in his own mind. A touch of narcissistic personality disorder perhaps. Did anyone grasp why he had the scoop closed? Probably just me.
 
Racerx said:
A legend in his own mind. A touch of narcissistic personality disorder perhaps. Did anyone grasp why he had the scoop closed? Probably just me.
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I think he said that he had it closed to force air to the intercooler. Now I’m watching the part where he is going to glue some channel material in front of the wheel wells AND tuft the area, instead of tufting first to see if one or more of his multiple guesses as to the problem is actually the cause. The scientific method doesn’t seem to exist in his hangar.
 
Engine designer for audi commented on his first flight video. He explained how poorly matched his turbos are for his application and why they are poorly matched. He suggests removing one turbo. It would increase hp from his current 230 to 300 and would eliminate at least some of his heat issue. Adding 5 gallons of coolant to get him 1000'agl does nothing when he was hoping to get in the flight levels.

Why has he not tufted the aircraft until now?
 
Dumb question so apologies up front. What is “tufting” exactly?
 
woodchucker said:
Dumb question so apologies up front. What is “tufting” exactly?
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Attaching bits of yarn or similar material to flight surfaces to make airflow visual. Among other things, he's going to find out there's no air going into the fuselage scoop.
 
Omalley1537 said:
His cooling issue “solution” of the two nose tanks, besides the obvious (adding weight to a pig)...
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I’ll admit that adding coolant capacity as ballast seemed very odd. But he did say there was no weight gain, since he removed an equal amount of ballast, from beneath the left seat, I think. Though it remains questionable whether that ballast was necessary - I think it was installed to equalize the plane’s weight between the two wheels, chasing after some roll issues in an odd fashion. In any case, moving the cg forward may help a bit with his pitch instability, so there’s that.

My pusher Sky Arrow will tend to overheat when stationary - there’s obviously no “fan” pushing large amounts of air into the cowling. It does have two small electric fans in front of the radiator to help a bit, though.
 
Salty said:
Good point. But trading a Mooney and another $100,000 to gain 20 knots and some cool factor is crazy beyond my ability to ignore it ;)
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I'd do it for the passenger space. Mooneys are a bit snug.
 
3393RP said:
Attaching bits of yarn or similar material to flight surfaces to make airflow visual. Among other things, he's going to find out there's no air going into the fuselage scoop.
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Thank you. :)
 
3393RP said:
Attaching bits of yarn or similar material to flight surfaces to make airflow visual. Among other things, he's going to find out there's no air going into the fuselage scoop.
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He already tufted the scoop and ground-tested it in the new video, so it is definitely getting lots of air. Now he can remove the tufts for his next flight, since he has proved that there is air going into the scoop.
 
I noticed he doesn’t seem too concerned about engine oil temp hitting 250 on the first flight. Generally oil is good to about what, 220? Anyone know what type oil he’s running in this thing?
 
Synthetic is good to higher temps, but on a quick search can't find any definitive answers for just how high. I know on the diesel truck forums 250 is considered the max temp.

*Edit* Found this: "Switch to Mobile Delvac 5W40 ESP fully synthetic engine oil with a higher shear temp. of 275 deg. F and oil breakdown at over 300 deg., (approximate)"
 
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Velocity173 said:
I noticed he doesn’t seem too concerned about engine oil temp hitting 250 on the first flight. Generally oil is good to about what, 220? Anyone know what type oil he’s running in this thing?
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Good point. I’d also note that I doubt Audi’s engineers designed the clearances in the engine for sustained operation at those temps, either. Likely 210 deg F coolant +/-, and normal oil temps with an allowance for brief higher temps.

If he manages not to bury the aircraft for other reasons, I’m guessing that engine is going to eat itself for lunch.

Audi should use this to tout their durability...
 
Sierra_Hotel said:
Synthetic is good to higher temps, but on a quick search can't find any definitive answers for just how high. I know on the diesel truck forums 250 is considered the max temp.

*Edit* Found this: "Switch to Mobile Delvac 5W40 ESP fully synthetic engine oil with a higher shear temp. of 275 deg. F and oil breakdown at over 300 deg., (approximate)"
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Geez. If my 6.0L PSD hit 230 I'd be pretty panicked running 5w40 Rotella synthetic. I rarely see it get over 205 on a 90-degree day.
 
Well if it’s 250 sump temp the actual temp of the oil running through the engine will be much hotter. Either way, hitting 250 on a short 3 minute flight with a relatively cool atmosphere, just ain’t normal.
 
schmookeeg said:
No way, it's genius. You don't need the same amount of spare coolant if you're only going 3,000 AGL vs 12,000.

He can put a tank in the nose and have gradiated markings for 2,000 feet of climb, 4,000, 6,000, etc. You can put in as much Prestone as you need for the day's flight, and SAVE the useful load that would otherwise go to wasted and unused cooling capacity.

From what I am seeing, he won't need coolant tank markings over 6,000, and even the 4 and 6 seem only theoretical at this point. :eek:
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Brilliant!
 
Velocity173 said:
Well if it’s 250 sump temp the actual temp of the oil running through the engine will be much hotter. Either way, hitting 250 on a short 3 minute flight with a relatively cool atmosphere, just ain’t normal.
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5 extra gallons of coolant and some tufts in the wheel well will fix it
 
SoonerAviator said:
Geez. If my 6.0L PSD hit 230 I'd be pretty panicked running 5w40 Rotella synthetic. I rarely see it get over 205 on a 90-degree day.
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Oh for sure, even with my 6.7PSD. I think 220-225 is the highest I've seen when I was up in the mountains and it was making me a little nervous.
 
..slightly OT, but kudos to Toyota..

even four wheeling in 100*+ heat, sometimes up steep trails in the mountains, the water temp has never gone above 195 and the oil temp never over 205. I don't trust the dash gauges so got this gauge and it verifies
 
Velocity173 said:
If the Raptor actually met its specs, then it would be far superior to a comparable Velocity TXL. The Raptor has a larger cabin. It’s cruise speed is 50 kts faster. It’s pressurized. It has deice. It has a BRS. $130K for a Raptor vs $250K for an TXL. All other numbers are similar. The question is, will the Raptor come close to those specs?
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It is my understanding that the prototype took 2.7 million $ and that it is not pressurized.
 
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Another thing he mentioned in his video was a guess for why the aircraft was bobbing up and down. He mused that it might be the size of his mouseholes in the vertical bulkheads in his fuel tanks. This picture is part of my own velocity build - the "mouseholes" are those half holes you see at the ends of the vertical baffles. In decades of following the velocity community I've never seen a similar issue be related to such holes. PM suggested he might spray foam inside his tanks? I would suggest he fly with full fuel but I know he is pretty heavy as is...
 
FormerHangie said:
People have become used to the rate of technological change in electronics and sometimes can be fooled into believing that there are giant leaps available in the physical world as well, but there are not.
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Yes! The physical world has actual laws. This is my thing with battery tech and development. Tesla has gobbs of money and their battery tech is incremental. I've done the work up on another post somewhere but that top of the line Tesla battery is no where near small enough, light enough, and with enough juice to be theoretically used in something like a Bonanza. Hybrid planes are even dumber since planes operate at sustained high power settings.. "use the gas to get up, electric to cruise, and charge on the way down" doesn't work in reality. Plus, each conversion of energy has losses.. it works in cars due to regenerative breaking and because of the long traffic and idle times.

kyleb said:
I'd start with the premise that there will be a few hundred or even a few thousand Audi 3.0L turbodiesel engines just sitting around in junkyards (but in pristine condition)
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The whole thing with this airplane that seems the least realistic is the power train. He has enough hurdles to overcome with the plane itself.. using junkyard audi engines is just madness.

jaxcessnadriver said:
I don’t get what extra coolant is going to do for him. He needs a remote oil cooler more than anything.
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That's what I thought he was doing first, putting some vents in the nose cone area with an additional cooler. The only thing 5 gallons of coolant will do is make it take longer to heat up, but also that much longer to cool down. It's probably the dumbest and most illogical solution to the cooling issue he could have possibly come up with.
 
Sierra_Hotel said:
Oh for sure, even with my 6.7PSD. I think 220-225 is the highest I've seen when I was up in the mountains and it was making me a little nervous.
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Normally run 190 Coolant/195 Oil running down the highway on a mid-80's day, nothing in tow. I think my alarm on the SCT Livewire is set for 220, lol. I haven't had a chance to tow with it just yet, so we'll see what it looks like with a 5K lbs boat or 7K lbs car-hauler in tow.
 
SoonerAviator said:
Normally run 190 Coolant/195 Oil running down the highway on a mid-80's day, nothing in tow. I think my alarm on the SCT Livewire is set for 220, lol. I haven't had a chance to tow with it just yet, so we'll see what it looks like with a 5K lbs boat or 7K lbs car-hauler in tow.
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Same here. Might touch 200 down here on the Gulf Coast on really hot days but I've never worried about it. Running through Arizona and Nevada when ambient was 117 and I had a 3,000 lb camper in the bed was a little different :lol:
 
Datadriver said:
It is my understanding that the prototype took 2.7 million $ and that it is not pressurized.
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It was pressurized, but he had a window break in the hanger overnight, so once that happened he decided not to change it out and then cut some more holes for his changes to the aileron cables.
 
Volzalum said:
It was pressurized, but he had a window break in the hanger overnight, so once that happened he decided not to change it out and then cut some more holes for his changes to the aileron cables.
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Do you know when that was? I'd like to see his video discussion about the early changes to the flight control system. I'm still baffled by the change from pushrods (as claimed in the website) to cables (as seen in all recent videos).

Tantalum said:
It's probably the dumbest and most illogical solution to the cooling issue he could have possibly come up with.
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Tread lightly. It's way too early for any superlatives.
 
Datadriver said:
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Another thing he mentioned in his video was a guess for why the aircraft was bobbing up and down. He mused that it might be the size of his mouseholes in the vertical bulkheads in his fuel tanks. This picture is part of my own velocity build - the "mouseholes" are those half holes you see at the ends of the vertical baffles. In decades of following the velocity community I've never seen a similar issue be related to such holes. PM suggested he might spray foam inside his tanks? I would suggest he fly with full fuel but I know he is pretty heavy as is...
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Not spray foam. Fuel cell foam. Keeps the fuel from sloshing around as much. Extremely coarse spongy foam you can scrunch up and put through the fuel cap. It in no way will solve anything. Much like his reasoning on the landing gear and putting "L channel"(he means angle) in front of the opening. Rather than him making something to fit the void. Tape would have been a much simpler easier solution.
 
iamtheari said:
Do you know when that was? I'd like to see his video discussion about the early changes to the flight control system. I'm still baffled by the change from pushrods (as claimed in the website) to cables (as seen in all recent videos).
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He had already scrapped the push rods for mostly cables awhile ago, way before the window broke. The window broke after he had the "wild ride" video. Then he decided to put in larger pulley's, etc after the window broke. He dumped the push rods before closing up the wings while he still had help on the project.
 
Volzalum said:
He had already scrapped the push rods for mostly cables awhile ago, way before the window broke. The window broke after he had the "wild ride" video. Then he decided to put in larger pulley's, etc after the window broke. He dumped the push rods before closing up the wings while he still had help on the project.
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Thanks for that timeline. I didn't realize that he had made it that far while still planning pressurization in the prototype.
 
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