Raptor Aircraft

Interesting quotes:

1) On this particular flight I felt like the airplane was just not performing very well.

2) The engine "is pushing the prop beyond what it was designed to run at." (I've noticed that he mentions "pulling the prop back to 3700 RPM". Pretty sure he means the engine but he doesn't seem to know what the prop RPM is.

3) "I think the prop is cavitating a bit."

And that's just in the first two minutes! You can't make this stuff up.
 
This dudes airmanship/ADM is atrocious. He requests depart to the pattern, well knowing he wants to climb overhead. Departs, blows past pattern altitude then tower has to ask WTF he’s doing. I don’t get why he doesn’t request to depart and orbit overhead and if necessary just request to come in!
 
School me: How do you figure out the approach speed (Vs x 1.3) if you don’t know the stall speed?

Assuming the airspeed indications are correct, it looks like the wing+ canard combo ends its desire to lift at around 90 kts, based on watching the landings. If so, then approach speed should be 117 kts.
 
FastEddieB said:
Using an o-ring as a spring washer seems a little odd, no?
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Under normal circumstances, yes.

In this entire situation, it’s just one more band-aid in a long line.

Ive seen better thought-out solutions on the 78 Cadillac “project” in the front yard of the local drug house than what this guy is doing.
 
FastEddieB said:
Using an o-ring as a spring washer seems a little odd, no?
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Meh. I've done it in my professional life. Just depends on what level of damping you're going for as well as longevity and environment.
 
455 Bravo Uniform said:
School me: How do you figure out the approach speed (Vs x 1.3) if you don’t know the stall speed?

Assuming the airspeed indications are correct, it looks like the wing+ canard combo ends its desire to lift at around 90 kts, based on watching the landings. If so, then approach speed should be 117 kts.
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Based on comments by Marc Zeitlin (who visited the project w/Wasabi and built/flys a Cozy Mk IV), the stall speed shouldn't be nearly that high based on wing loading. Marc (IIRC) has indicated that it might be a bit more than a normal Cozy, which has a stall speed of 60ish knots. So, even if the canard stalled at 70 knots, the approach speed *shouldn't* be much more than 90 knots, which is still a lot for a single engine recip that doesn't have a Merlin or R-2800 on the front.

Saturday morning edit: To add to this, the CAFE foundation did a very detailed evaluation of the COZY MKIV and found that its minimum speed (canard stall) was between 61 and 71 knots, depending on weight and CG. So if the Raptor adds 10 more knots to that, and we multiply by 1.3 for a safety factor, that would be as much as 105 knots on final.
 
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455 Bravo Uniform said:
School me: How do you figure out the approach speed (Vs x 1.3) if you don’t know the stall speed?

Assuming the airspeed indications are correct, it looks like the wing+ canard combo ends its desire to lift at around 90 kts, based on watching the landings. If so, then approach speed should be 117 kts.
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Geezus - may as well be an A7 Corsair shooting targeting the meatball...


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Mtns2Skies said:
Meh. I've done it in my professional life. Just depends on what level of damping you're going for as well as longevity and environment.
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I wasn’t dismissing it out of hand - if I was working on a riding mower or other non-critical appliance I might consider something like that as well to snug things up. But in an extreme “environment” that calls for a certain “longevity” it seemed a bit slapdash, is all.
 
This is how I picture Peter's bathroom. There I fixed it blog. Peter definitely needs some of his fixes posted there.
 

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Racerx said:
Which category do the zip tied paper towel stop leak fix fall under?
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Haha, a YT commenter who claims to be an A&P said that's standard practice for small oil leaks from fittings. I've never seen it but I'm no A&P, just a guy trying not to die.

I had a small in flight fire caused by a rag accidentally left behind by an A&P (and missed by me, so my fault too). That was a stressful event, to put it mildly. I can't imagine leaving tinder in the engine compartment intentionally, especially in an aircraft that is trying to self destruct in so many other ways at the same time.
 
231TC said:
Haha, a YT commenter who claims to be an A&P said that's standard practice for small oil leaks from fittings. I've never seen it but I'm no A&P, just a guy trying not to die.

I had a small in flight fire caused by a rag accidentally left behind by an A&P (and missed by me, so my fault too). That was a stressful event, to put it mildly. I can't imagine leaving tinder in the engine compartment intentionally, especially in an aircraft that is trying to self destruct in so many other ways at the same time.
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Likely the type of A&P who routinely lets folks leave their logs and 2-3 c-notes for an annual, minus a plane...
 
Racerx said:
Which category does the zip tied paper towel stop leak fix fall under?
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It is in harmony with the other engineering fixes performed on the aircraft, like, oh, I don't know, the half liter water bottle that's tie wrapped to the engine mount and being used as a radiator overflow reservoir.
 
3393RP said:
It is in harmony with the other engineering fixes performed on the aircraft, like, oh, I don't know, the half liter water bottle that's tie wrapped to the engine mount and being used as a radiator overflow reservoir.
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maybe he’s going for the rat-rod theme...needs more patina though...
 
3393RP said:
It is in harmony with the other engineering fixes performed on the aircraft, like, oh, I don't know, the half liter water bottle that's tie wrapped to the engine mount and being used as a radiator overflow reservoir.
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I thought he was trying to save weight. Plastic water bottle lighter than aluminum reservoir.
 
donjohnston said:
I think the prop is cavitating a bit
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Does he mean "stall"? Otherwise, this makes absolutely no sense. In a marine environment you get cavitation when the propeller causes excessively low pressure (lower than the fluid's vapor pressure) and turns the water to vapor, basically boiling it, in a sense

So he either thinks the propeller is stalling, but that doesn't make sense either.. wouldn't it suddenly spin much faster as it has ceased to create "lift".. (I've blocked the inlets to electric RC turbines effectively stalling it and the RPM shoots way up).. or, he thinks the blade tips are going supersonic (doubtful)
 
kyleb said:
Based on comments by Marc Zeitlin (who visited the project w/Wasabi and built/flys a Cozy Mk IV), the stall speed shouldn't be nearly that high based on wing loading. Marc (IIRC) has indicated that it might be a bit more than a normal Cozy, which has a stall speed of 60ish knots. So, even if the canard stalled at 70 knots, the approach speed *shouldn't* be much more than 90 knots, which is still a lot for a single engine recip that doesn't have a Merlin or R-2800 on the front.

Saturday morning edit: To add to this, the CAFE foundation did a very detailed evaluation of the COZY MKIV and found that its minimum speed (canard stall) was between 61 and 71 knots, depending on weight and CG. So if the Raptor adds 10 more knots to that, and we multiply by 1.3 for a safety factor, that would be as much as 105 knots on final.
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If I'm going 105 kts on final I want a turbine, preferably without a propeller.
 
Tantalum said:
So he either thinks the propeller is stalling, but that doesn't make sense either.. wouldn't it suddenly spin much faster as it has ceased to create "lift".. (I've blocked the inlets to electric RC turbines effectively stalling it and the RPM shoots way up)..
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Blocking flow through a fan is not 'stalling', it's blocking flow. Take a look at a drag polar for a typical airfoil and see if you still think RPM should wind up if a prop really stalls.

Nauga,
dragged down
 
nauga said:
Blocking flow through a fan is not 'stalling', it's blocking flow. Take a look at a drag polar for a typical airfoil and see if you still think RPM should wind up if a prop really stalls.

Nauga,
dragged down
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well it was counterintuitive to what I was expecting, I thought it would bog down but it's sped up.. but I guess that doesn't mean it was stalling, just spinning around in a circle. Is there any merit to Peter saying his propellers are cavitating?
 
Tantalum said:
Does he mean "stall"? Otherwise, this makes absolutely no sense. In a marine environment you get cavitation when the propeller causes excessively low pressure (lower than the fluid's vapor pressure) and turns the water to vapor, basically boiling it, in a sense

So he either thinks the propeller is stalling, but that doesn't make sense either.. wouldn't it suddenly spin much faster as it has ceased to create "lift".. (I've blocked the inlets to electric RC turbines effectively stalling it and the RPM shoots way up).. or, he thinks the blade tips are going supersonic (doubtful)
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Of course it makes no sense. Consider the source. A prop can't cavitate outside of a liquid environment.

If I had to guess, I would say that the pitch is too flat. But it's just a guess.

It would not surprise me one bit if doesn't know what his prop RPM is. It would also not surprise me if he thinks that the blade tips are going supersonic.
 
Tantalum said:
Is there any merit to Peter saying his propellers are cavitating?
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Is there a possibility that the word might be used differently in Australia? Aviation terminology does differ slightly, even in the English-speaking world.

Ron Wanttaja
 
He has said the reduction drive is 1.58:1 IIRC. He has mentioned engine speed as much as 4k rpm at times. That would put the prop at 2500 rpm... right? Is the prop diameter published?
 
donjohnston said:
It would not surprise me one bit if doesn't know what his prop RPM is. It would also not surprise me if he thinks that the blade tips are going supersonic.
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One would normally assume that the designer would use the max engine RPM and calculate the PSRU drive ratio from that to keep the prop tips subsonic. Or use some other way, if one has other priorities, but whatever - you end up knowing that either you can’t overspend the prop, or you have a known (and marked) do-not-exceed engine RPM. Just “ferinstance”, I know I can run my Rotax 912ULS at its 5800 RPM red line and the prop is still fine. I don’t need to calculate that my prop RPM in cruise is 2139 RPM or whatever. Don’t care, doesn’t matter.

Normally.

In this guy’s case I don’t think I would make any bets. He may have covered it in an early video or something, but I’m certainly not interested enough to watch hours and hours of slow motion train wreck to find out.

Edit: I see @Bacho found it. Ought to be trivial to figure it out.
 
wanttaja said:
Is there a possibility that the word might be used differently in Australia? Aviation terminology does differ slightly, even in the English-speaking world.

Ron Wanttaja
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I mean, anything is possible.. I'm genuinely curious what he means by it
 
Didn’t he also mess around with some sort of pitch adjustment (maybe the stops) with a wrench in earlier videos?
 
donjohnston said:
Of course it makes no sense. Consider the source. A prop can't cavitate outside of a liquid environment.

If I had to guess, I would say that the pitch is too flat. But it's just a guess.

It would not surprise me one bit if doesn't know what his prop RPM is. It would also not surprise me if he thinks that the blade tips are going supersonic.
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Any chance he thinks he's getting a rotor wash effect? I think it's hogwash regardless and any perceived horsepower loss is probably the engine laying over.
 
wanttaja said:
Is there a possibility that the word might be used differently in Australia? Aviation terminology does differ slightly, even in the English-speaking world.
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I grew up around boats in Australia, and have a small amount of PIC time there as well, and the meaning of the word was always pretty much the same as it is here in California. That doesn't mean it's not used differently somewhere there, but not in the circles I was a part of...
 
Actually, he's sort of out of the pattern
 
He's buzzing around at 2,000' out of gliding distance from the airport in an airplane with a very suspect drivetrain and a landing speed that approaches 100 mph. He's gotta be smarter.
 
40 minutes and counting, looks like he might be on final. Is that is record duration?
 
About the same as the last flight.
 
My favorite part is when he discovers his stall characteristics are not benign after his belts snap and he looses all power outside of gliding distance to the airport. Oh wait.... that happens in an upcoming video
 
pilotrick said:
My favorite part is when he discovers his stall characteristics are not benign after his belts snap and he looses all power outside of gliding distance to the airport. Oh wait.... that happens in an upcoming video
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My concern is he finds out the stall characteristics on about a 1/2 mile final. You explore the edges of the envelope at a safe altitude, so you know where they are at all times.
 
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