Raptor Aircraft

The string he's using for the tufts seems somewhat "brittle" - probably inconsequential but I'd assume you want something less stiff.

The wheel wells are now effectively "closed" with a large piece of aluminum taped on. I'll be curious to see on the next flight how much, if any, effect that has on control
 
Tantalum said:
The string he's using for the tufts seems somewhat "brittle" - probably inconsequential but I'd assume you want something less stiff.

The wheel wells are now effectively "closed" with a large piece of aluminum taped on. I'll be curious to see on the next flight how much, if any, effect that has on control
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I’d bet it won’t help at all. He needs to carefully check his rigging on the aero side and do a ton of work on the engine/psru. Otherwise, he’s just wasting time playing in the margins.
 
The pedals are the most fun of flying a VariEze. Pushing both of them at the same time is a significant eye opener the first time you do it.

The Eze does do a decent flare, though.
 
FastEddieB said:
Educational. Thanks!

Helps to visualize what might be going on with the Raptor’s pitch oscillations.

Landing that flat must make nose gear adjustment and wheel balance super-critical.
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When I did my training at Velocity my first few approaches were horrible. Very sensitive in pitch and the control forces are a bit stiff. Just like in Peter’s landing I was porposing because I was trying to flare too much. It’s not a completely flat profile, just a slight nose up works well.

Now during flight, I have no idea what’s causing his pitching and rolling issues. He might need some VGs on both the canard and main wing.
 
FastEddieB said:
Sure. But it looks to me that nosewheel is touching down maybe 10 or even 20 kts faster than if you had a conventional elevator to hold it off longer.
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Depends on which conventional plane.

I have an XL-RG. I touchdown at ~70kts and the nose gets lowered soon after that. My canard stalls around 65kts so I want the nose on the ground before that.
 
I've also noticed (by mistake) in ground effect, my canard stalls at a slower speed. At altitude, it’ll stall just shy of 60 kts but I’ve had the nose up at 55 just before touchdown still producing good lift. Don’t wanna go out and test what it actually stalls at IGE but I do know that at light weights and I screw up the landing, there’s some wiggle room there.
 
Velocity173 said:
I've also noticed (by mistake) in ground effect, my canard stalls at a slower speed. At altitude, it’ll stall just shy of 60 kts but I’ve had the nose up at 55 just before touchdown still producing good lift. Don’t wanna go out and test what it actually stalls at IGE but I do know that at light weights and I screw up the landing, there’s some wiggle room there.
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Do you think it’s the canard in ground effect or the wings in ground effect that weaker canard lift still affects? That whole partially stalled jazz. I guess it doesn’t much matter, right? Just hangar chat.
 
455 Bravo Uniform said:
Do you think it’s the canard in ground effect or the wings in ground effect that weaker canard lift still affects? That whole partially stalled jazz. I guess it doesn’t much matter, right? Just hangar chat.
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Oh I don’t know. Obviously the canard is designed to stall first so I can’t test when the main wing stalls.

Basically if you don’t have the mains down yet with the nose up, things are going to get ugly if you stall. In my situation, I’ve had the mains down but was trying to do a smooth let down with the nose. Even that situation might do some damage if the canard stalls. It’s not an aircraft that you want to hold the nose off for an extended period of time. Just wanna let the mains touch and shortly after that, lower the nose.
 
In today's episode of How the Canard Spins, the protagonist experimentally determines the additional amount of elevator trim required for takeoff due to moving ballast from the floor to the nose, where additional coolant expansion tanks are to be located. I don't want to spoil the ending about what happens to the elevator trim spring. (It breaks.) I don't want to spoil the aerodynamics puzzle that only careful-minded watchers will catch. (After a first flight during which people who know a lot about canard flight dynamics observed that the bucking motion was likely due to the canard stalling, he has added weight to the nose and now the craft requires noticeably more elevator motion to lift the nosewheel.) I don't want to spoil what will happen the next time the craft leaves, or maybe even enters, ground effect. (The canard will stall, and it will do so off the end of the runway because that's how far it will travel before it makes it out of ground effect.)

What I came here to spoil is this thread from the comments section:

Hi Peter! As a former developer for the Audi/BMW/VW/Renault Diesel engines, please take my advice for a little but effective quick fix. I noticed that your turbo setup is limiting your power output while increasing the EGT by far! If you get rid of the first turbo stage and only use the HP turbo, you will get ~30% higher power output and the EGT will drop significantly. It's a quick fix and you will fix two goals at once: more power and less waste heat. I like your project, keep it up and lets get to finish line!
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Peter will not consider the possibility that he might be wrong. He has consistently rejected advice from experts such as yourself, Wasabi, and others, to focus on the next "Quick Fix", unsurprisingly the aircraft is overweight, underpower, and has a myriad of problems.
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RAPTOR AIRCRAFT: It's not a quick fix. It would require removing all kinds of plumbing and then reconnecting. You should realize that this would hardly be a quick fix.
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Removing and reconnecting plumbing (let's exaggerate and say it is 1 week of work). Isn't that worth an extra 30% power + cooling help? You have spent more than a week already chasing cooling gremlins. Why not give it a shot? The potential gains are massive.
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It also would likely require retuning the engine, taxi testing, thrust testing, etc etc etc. Conservatively I would say its more like a month of work to validate the new setup. He has something that seems like it will work for this phase of testing. Should he try that in the long run? For sure! But removing a turbo because of a youtube comment is a MAJOR change on the advice of someone who's identity and qualifications are not immediately verifiable.
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While removing the bonus turbocharger would require some testing, all of which is required anyhow, and is more than just "something that seems like it will work for this phase of testing," I can think of a few things that removing that turbo would not require. Chief among them: An all but guaranteed canard stall off the end of the runway due to moving the CG farther forward from where it was when the thing was already actively trying to kill its designer. (Hmm...shades of Jurassic Park? At least the craft has an appropriate name.)
 
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iamtheari said:
In today's episode of How the Canard Spins, the protagonist experimentally determines the additional amount of elevator trim required for takeoff due to moving ballast from the floor to the nose, where additional coolant expansion tanks are to be located. I don't want to spoil the ending about what happens to the elevator trim spring. (It breaks.) I don't want to spoil the aerodynamics puzzle that only careful-minded watchers will catch. (After a first flight during which people who know a lot about canard flight dynamics observed that the bucking motion was likely due to the canard stalling, he has added weight to the nose and now the craft requires noticeably more elevator motion to lift the nosewheel.) I don't want to spoil what will happen the next time the craft leaves, or maybe even enters, ground effect. (The canard will stall, and it will do so off the end of the runway because that's how far it will travel before it makes it out of ground effect.)

What I came here to spoil is this thread from the comments section:











While removing the bonus turbocharger would require some testing, all of which is required anyhow, and is more than just "somethign that seems like it will work for this phase of testing," I can think of a few things that removing that turbo would not require. Chief among them: An all but guaranteed canard stall off the end of the runway due to moving the CG farther forward from where it was when the thing was already actively trying to kill its designer. (Hmm...shades of Jurassic Park? At least the craft has an appropriate name.)
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The level of narcissism this guy possesses is mind-blowing. He has years of work, big problems, likely millions of dollars tied up...a developer for his choice of engine is giving free advice, and he rejects it. Worse, his rationale is simply because it’s not “quick.”

I’m trying to see things from Peter’s point of view, but I can’t seem to fit my head that far up my...well, you know.
 
Been following this Raptor project for a couple years now, always provides a good chuckle. I'm waiting for the post incident movie.
 
Dave Theisen said:
Bandaids are quicker than fixes. :)
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Why apply a not-quite-quick fix when there are so many really-not-that-quick-either non-fixes to choose from? His actual skills are such that he probably could have removed the bonus turbo and designed and built a new cowl in less time than he has spent waiting for new coolant tanks.
 
iamtheari said:
Why apply a not-quite-quick fix when there are so many really-not-that-quick-either non-fixes to choose from? His actual skills are such that he probably could have removed the bonus turbo and designed and built a new cowl in less time than he has spent waiting for new coolant tanks.
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I think you vastly overestimate his skills. He had paid help until last summer and has made virtually no progress since it was inspected by a DAR last August.

Think about it. 14 months since the airplane was theoretically ready for flight and he has completed one spooky 2 minute test flight. Along with 50ish videos.
 
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He won't remove the turbo because he would have to figure out a new tail number. "2TD" 2 turbo diesel. Yes I think Peter really is that petty and stubborn.
 
WWFeldman said:
With possibly his life hanging in the balance, that's his answer. Somebody who cares for that man needs to sit him down and have a "come to Jesus" meeting with him.
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I don’t think this personality type has a large social circle, which is maybe part of the problem. No one to call him out, or talk things through over a beer.

I really hope this guy doesn’t die. I think this project needs to be shelved and he can have a great story to tell his fellow software developers while he builds his RV.
 
At pretty much every airport there are great people with valuable skills and knowledge hanging around who will help with anything they can. Peter has run off quite a few of them with his attitude.
 
Racerx said:
He won't remove the turbo because he would have to figure out a new tail number. "2TD" 2 turbo diesel. Yes I think Peter really is that petty and stubborn.
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"1TD".. might be available
 
231TC said:
At pretty much every airport there are great people with valuable skills and knowledge hanging around who will help with anything they can. Peter has run off quite a few of them with his attitude.
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Not just that. He has deliberately avoided onlookers. I think in one of his videos, either the video or the comments, when he first moved to the airport, he said that he would shut down whatever he was doing if anyone came out to watch.

Dealing with everyone coming to gawk at your creation and interfere with your progress is a legitimate problem. I have had visitors while building my airplane, and I could just as well have taken those days off completely for all the work I got done with them around.

But Peter actively rejects valid input from valid sources for invalid reasons.
 
iamtheari said:
Dealing with everyone coming to gawk at your creation and interfere with your progress is a legitimate problem. I have had visitors while building my airplane, and I could just as well have taken those days off completely for all the work I got done with them around.
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Rutan used to have a 7 minute rule. He'd talk for 7 minutes, then you were welcome to either stay and help or to go away.
 
Peter's latest video. His comments at about the 6 minute mark... "With a more forward CG, the canard will be at a lower AOA and..."


He's got that backwards, right?
 
iamtheari said:
Not just that. He has deliberately avoided onlookers. I think in one of his videos, either the video or the comments, when he first moved to the airport, he said that he would shut down whatever he was doing if anyone came out to watch.

Dealing with everyone coming to gawk at your creation and interfere with your progress is a legitimate problem. I have had visitors while building my airplane, and I could just as well have taken those days off completely for all the work I got done with them around.

But Peter actively rejects valid input from valid sources for invalid reasons.
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Yeah it can be problem, I've been keeping my hanger doors closed lately while building my RV.
 
He just got the tanks back? Damn. We're slammed but welding a couple end plates and a few bungs is a 20 minute job, and that includes pressure testing. Tells me the fav shop isnt set up for that kind of work or he really ****ed em off at some point.
 
Racerx said:
He just got the tanks back? Damn. We're slammed but welding a couple end plates and a few bungs is a 20 minute job, and that includes pressure testing. Tells me the fav shop isnt set up for that kind of work or he really ****ed em off at some point.
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My new standard response to all “Either A or B” explanations for the Raptor applies here: Can’t it be both?
 
246 degrees is cookin. Not quite break down the viscosity cooking, but getting close.


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He also claimed that the plane will have less drag because more of the lift will be supplied by the canard instead of the draggier main wing. I don’t know if that is true or not. Both possibilities (1, he doesn’t understand his own design; 2, his main wing has so much drag that the canard is a better source of lift) seem problematic to me.
 
iamtheari said:
He also claimed that the plane will have less drag because more of the lift will be supplied by the canard instead of the draggier main wing. I don’t know if that is true or not. Both possibilities (1, he doesn’t understand his own design; 2, his main wing has so much drag that the canard is a better source of lift) seem problematic to me.
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I agree with your #2. It seems like the wing should be more efficient than the canard, if properly designed.
 
Tantalum said:
My last note on this, and then we can start a new thread or dig up one of the countless others

Just look at the marine outboard industry.. even 2-strokes. What you can buy today brand new from Honda or Evinrude or any of those guys is not at all comparable to what they were selling in the 1950s

The marine environment is harsh, and at least in the case of outboards also necessitates relative lightweight and dependability so that poor guy out fishing 20 mi from shore in his center console can still get home. Mind you, these engines will go hundreds of hours at 4,000 RPM..

Financials aside, we have not reached the apex of what ga piston can technically, physically achieve
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Just a note, as I worked in a large marina in the 1980s: the manufacturer's maintenance trainers actually gave the life for outboards in thousands of hours (all two-strokes then) but I/O's were in the hundreds before any major work. The actual mess of the double-U-jointed tilting lower unit in the I/O was the issue; the engines were awesomely indestructible, as they were car engines, if you kept the water in the cooling jackets and out of the cylinders. The two-strokes benefitted from decent cooling, and a rich mixture (which burned cooler and delivered more oil).
I'm still planning on a car engine conversion, but we'll see. COVID has adjusted my retirement plan. I will use a proven airframe, however. The Raptor (and the designer's attitude) scares me.
 
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