Raptor Composite Aircraft

[Kyle Boatright]

Definitely an exercise in how to build a prototype the most expensive way possible

As has been pointed out by guys who've been there/done that, he could have done a true prototype for a fraction of that using moldless composite techniques. Buy a set of infinity retracts and have a nice "shape" to fly, modify, and show at the airshows. He could still have bolted the Audi on the back. Instead...

I was reading something on another site today (TheDrive.com) where they went into Lockheed's Skunkwork's philosophy that getting to a prototype quickly is critical. The Raptor is, or should be, a simple airplane and is 5 years in without a real flight. The SR-71 took less than 3 years and that was revolutionary technology...

 

[BoKu]

Wow, I just read the comments on the latest vid. They're in full-on circle-jerk mode now. Very weak signal to noise ratio.

 

[BoKu]

As has been pointed out by guys who've been there/done that, he could have done a true prototype for a fraction of that using moldless composite techniques. Buy a set of infinity retracts and have a nice "shape" to fly, modify, and show at the airshows. He could still have bolted the Audi on the back. Instead...

I was reading something on another site today (TheDrive.com) where they went into some of Lockheed's Skunkwork's philosophies that getting to a prototype quickly is critical. The Raptor is, or should be, a simple airplane and is 5 years in without a real flight. The SR-71 took less than 3 years and that was revolutionary technology...

Mythbusters is also strong on that MO. Design, build, try, re-design, re-build, fly.

 

[pictsidhe]

With the suck it and see design method of the Raptor, building such an expensive prototype was sheer lunacy.

 

[Orange4sky]

Nor are carbon fiber reinforced molds

I was wondering why the frig, unless you needed to burn money, would you use CF to reinforce a mold that has no real weight restriction? Just use glass and double up. Am I missing something?

A buddy of mine just bought a similarly large bed CNC that had been used for making Freightliner molds. It was a distress sale or bankruptcy. I think he paid ~$45,000 CAD. I have no idea what market value is on that new.

 

[pictsidhe]

He made the moulds FROM carbon? I should be surprised...

 

[foolonthehill]

If you are buildng your parts from carbon, and expect to take full advantage of the strength of epoxy resin systems, you are going to post cure your parts in an oven. Fiberglass tooling and carbon fiber parts is not a good method, as fiberglass tooling, often made with VE or ISO resins, have a far different CTE than carbon. The fiberglass expands during temperature ramp up, as does the carbon part as it cures. When you ramp the oven temp back down, the fibrglass contracts, the carbon does not. Do if it's a really simple, open geometry tool, no real issues (one something with non critical tolerances) but with more complex tooling, you get a trapped part, and since it's usually a much lighter laminate, you also get the possiblility of the fiberglass tool actually damaging, or in an extreme case, crushing the carbon part.

 

[wsimpso1]

Just watched the latest. So after all that nonsense with fishing weights zip tied in the winglet, he flies it with a fuel imbalance. Asked why he would go to the trouble to install weights to balance it and then fly with one wing heavier from fuel, he says he has no control over the fuel distribution...it goes where it wants on the return from the engine.

So what was the purpose of the flight/hop? He says he's trying to eliminate possibilities as the cause of his roll by balancing the weight and waiting for a calm day, but he flew with both a crosswind and unbalanced weight. So those two things he was supposedly eliminating are still just as much of a question as before.

I do not get all this concern over getting the balance right to within a few pounds. Real world he can have both fuel and seating asymmetric, crosswinds, and it must still have enough aileron and rudder to line up and stay lined up. A few pounds should be no big deal...

I am getting on to whether the issue of is PM not putting in enough correction to stay on centerline, or is the airplane not able stay on centerline even with crosswind corrections? I am in agreement that a camera on both ailerons sounds necessary to sort that out.

Billski

 

[wsimpso1]

If you are buildng your parts from carbon, and expect to take full advantage of the strength of epoxy resin systems, you are going to post cure your parts in an oven. Fiberglass tooling and carbon fiber parts is not a good method, as fiberglass tooling, often made with VE or ISO resins, have a far different CTE than carbon. The fiberglass expands during temperature ramp up, as does the carbon part as it cures. When you ramp the oven temp back down, the fibrglass contracts, the carbon does not. Do if it's a really simple, open geometry tool, no real issues (one something with non critical tolerances) but with more complex tooling, you get a trapped part, and since it's usually a much lighter laminate, you also get the possiblility of the fiberglass tool actually damaging, or in an extreme case, crushing the carbon part.

I never followed the process that closely... did this bird get oven cured and post cured? If true, you not only need carbon fiber molds, but you need it to be the same carbon as the parts and in the same schedule. Carbon fiber has negative thermal expansion along the fibers, but positive across them, and each mill that makes the fiber gets a slightly different set of these characteristics. This does drives you to use the same fiber and orientation schedules, so that the cured part is the same shape as the mold when it comes out...

Going opposite that is the white paint on the prototype - light colors are needed for room temp cured resins to stay below Tg... if PM had oven cure parts, why the boring white paint?

Billski

 

[rv6ejguy]

The airframe parts were post cured in an oven. That's when the windows BONDED on the OUTSIDE of the pressure vessel let go.

 

[pictsidhe]

I do not get all this concern over getting the balance right to within a few pounds. Real world he can have both fuel and seating asymmetric, crosswinds, and it must still have enough aileron and rudder to line up and stay lined up. A few pounds should be no big deal...

I am getting on to whether the issue of is PM not putting in enough correction to stay on centerline, or is the airplane not able stay on centerline even with crosswind corrections? I am in agreement that a camera on both ailerons sounds necessary to sort that out.

Billski

A camera on the yoke and Peter's legs would be very enlightening. Probably why there isn't one.

 

[BBerson]

why the boring white paint?

It's primer.

 

[BJC]

It's primer.

Yup, he got weight conscious when it came time to paint the Raptor.


BJC

 

[cblink.007]

As has been pointed out by guys who've been there/done that, he could have done a true prototype for a fraction of that using moldless composite techniques. Buy a set of infinity retracts and have a nice "shape" to fly, modify, and show at the airshows. He could still have bolted the Audi on the back. Instead...

I was reading something on another site today (TheDrive.com) where they went into Lockheed's Skunkwork's philosophy that getting to a prototype quickly is critical. The Raptor is, or should be, a simple airplane and is 5 years in without a real flight. The SR-71 took less than 3 years and that was revolutionary technology...

Indeed. The A-12 went from clean slate to first flight in less than 3 years. If I recall from the book "Skunk Works", it went from clean slate to fully assembled and ready to test in just 23 months.

However, that aircraft was the progeny of a skilled engineering and fabrication team with competent leadership that had a defined set of requirements and a defined need for a solution. They had task and purpose, and went forth. They kept it as simple as possible, engineered what had to be engineered (everything), kept requirements and configurations standardized, and what came out was something that worked...and worked extremely well. And, believe it or not, they managed to pull it off without daily Fakebook/Insta/YouTube updates! [sarc]

That has not existed for the Raptor. I'll hand it to PM and his tiny crew that made a nice, shiny & pretty airplane from the outside, but while they have good initiative, some awful judgement has prevailed. A science project of an engine sourced from wrecked cars, an overweight structure, bad mechanical control design, perhaps even a questionable business model, etc.

He would have been so much better off with a simplified bare-bones prototype with as much off the shelf (proven) equipment as possible, and certainly without the self-inflicted pressure of his nonstop social media presence.

At the end of the day, this aircraft is proving more and more to be an extremely expensive and convoluted exercise at arriving to a solution that already exists- Velocity.

 

[C Michael Hoover]

[OOPS duplicate post]

 

[Mcmark]

I can only watch his stuff when I'm in the right frame of mind (think NASCAR waiting to see the crash) and I noticed his knees constantly dancing. Either he's a nervous Nelly, or the Raptor is not stable at those speeds.

 

[pictsidhe]

The airframe parts were post cured in an oven. That's when the windows BONDED on the OUTSIDE of the pressure vessel let go.

Indeed. The A-12 went from clean slate to first flight in less than 3 years. If I recall from the book "Skunk Works", it went from clean slate to fully assembled and ready to test in just 23 months.

However, that aircraft was the progeny of a skilled engineering and fabrication team with competent leadership that had a defined set of requirements and a defined need for a solution. They had task and purpose, and went forth. They kept it as simple as possible, engineered what had to be engineered (everything), kept requirements and configurations standardized, and what came out was something that worked...and worked extremely well. And, believe it or not, they managed to pull it off without daily Fakebook/Insta/YouTube updates! [sarc]

That has not existed for the Raptor. I'll hand it to PM and his tiny crew that made a nice, shiny & pretty airplane from the outside, but while they have good initiative, some awful judgement has prevailed. A science project of an engine sourced from wrecked cars, an overweight structure, bad mechanical control design, perhaps even a questionable business model, etc.

He would have been so much better off with a simplified bare-bones prototype with as much off the shelf (proven) equipment as possible, and certainly without the self-inflicted pressure of his nonstop social media presence.

At the end of the day, this aircraft is proving more and more to be an extremely expensive and convoluted exercise at arriving to a solution that already exists- Velocity.

When Peter started this, he thought he could just draw something in CAD, make it and it would work as he imagined. He had absolutely no clue how much engineering or experience is actually required for that to be likely. He has gone straight to a production ready Dodo. Said Dodo needs to be relegated to static display, and another prototype designed and built from the ground up, is that one going to be another $3,000,000 production ready one? He could have been on his second prototype by now.

 

[WonderousMountain]

This describes me, minus 5-10 Million $$$

 

[Hot Wings]

and I noticed his knees constantly dancing

So I'm not the only one that thought it looked like taildragger in a cross wind?

 

[TFF]

Castering nose wheel. I would expect a dance. If he is dragging brakes. It’s probably from keeping it straight dragging them.