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Raptor Composite Aircraft

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231TC

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He didn't tell me that. Jeff said he didn't design it. If an IT guys hires an engineering firm to assist with the design I would expect the engineering firm would advise about weight. Is there evidence that the IT guy insisted that the engineered plans and layups be made heavier?
Or is there a conflict in that the website listed the weight at 1800 pounds for years? Then it was changed to 2300 now. Should be listed at least 2800 pounds.
How could any engineering firm work with that 1800 pounds number if they had knowledge that the IT guy wanted features far beyond similar Velocity weight?
The engineering firm should have worked with an empty weight estimate around 2600-2800 pounds, is my guess.
I got the impression that the engineer (Mark B) was only a consultant used in a piecemeal approach for various parts of the design, not hired to do a comprehensive design. That's no way to design a complex aircraft where every part of every system must work together, but it does seem to be Peter's way. Like someone else said, he is smart enough to hire pros for the things he knows he doesn't know, but he doesn't know all the things he doesn't know.

I suspect Peter created the weight specs himself, just wildly guessing without engineering being a part of it at all. Pretty sure he outright said he started with 1800 because that was what the Velocity was.
 

TarDevil

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I doubt that any hired engineer would neglect to first check the actual weights of existing Velocity and Orion and then add another 500 pounds (2300) total) for the pressurization, compound turbos and A/C, parachute and whatever else the dreamer wanted at that time.
When I did all the long range maintenance planning for a major airline I was paid to determine what work needed to be done, how much labor that work would require against how much labor was available. If I calculated a hanger visit at 32 days, I was told to plan it at 18.

Do you see where I'm going? The wisdom of "engineers" and other professionals are not always heeded.
 
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BoKu

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That's one company. I believe the majority of German gliders and motorgliders have solid fuselages. Ask Boku? I think pressurized dictates solid core less, at least the cockpit...
Yeah, I don't really know. Most of the single-seaters I've looked into don't have foam core in the fuselage. But I haven't seen many of the latest generation gliders broken open to where I can see into them. I know that some of the two-seaters like ASK21 have areas of honeycomb, which make them a pain to repair.

As a data point, five plies of 7725 fibrglass, three 0/90 and two +/-45 is a common fuselage base layup. Unless the paint is real thick, when you look inside they are lit up by sunlight coming in through the laminate.

I'd think that unless the fuselage is circular in cross-section, you'd want some foam core to give it panel stiffness against the out-of-plane pressurization forces.
 

BJC

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Pretty sure he outright said he started with 1800 because that was what the Velocity was.
Well that made sense: bigger airplane, more stuff in the interior, a complete junkyard aft of the firewall, pressurized, couple of turbos, liquid cooling, PSRU, massive doors, and air conditioned, not to mention primary structure. Sure, it will weigh the same. Then add ballast, steel plate, lots of Rube Goldberg control fixes, and you have .... Raptor, the Cirrus Beater.


BJC
 

BBerson

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Do you see where I'm going? The wisdom of "engineers" and other professionals are not always heeded.
Exactly. If he listened to all the engineers he would not even consider an auto diesel or canard or anything as a first try. But his engineer stuck with it.
And it has worked for several months so far.
 

pictsidhe

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Exactly what part of Raptor would be a new invention?

Isn't PM inviting the beatings?
Expecting it to break the laws of physics.
I got the impression that the engineer (Mark B) was only a consultant used in a piecemeal approach for various parts of the design, not hired to do a comprehensive design. That's no way to design a complex aircraft where every part of every system must work together, but it does seem to be Peter's way. Like someone else said, he is smart enough to hire pros for the things he knows he doesn't know, but he doesn't know all the things he doesn't know.

I suspect Peter created the weight specs himself, just wildly guessing without engineering being a part of it at all. Pretty sure he outright said he started with 1800 because that was what the Velocity was.
Peter got his empty weight estimate by looking at the weight of his competition. He has said that he didn't know how to calculate it.
 

BBerson

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hammer

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The composite fuselage aircraft that I have flown (Glasair and Sportsman) have foam cores.
BJC
The composite fuselage aircraft I have flown (and owned) had solid carbon fiber construction (no foam).

Not only that:

MT prop
No Lycoming or Continental either. (Some sort of converted industrial unit with an aviation pressure carb and automatic mixture control. Used an aftermarket supercharger. Did make 400hp though)

If peter wanted to save weight,
he could switch to magnesium.
And my plane had a magnesium control system.

(sorry just couldn't resist)
 

BBerson

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Seriously?
I meant the PSRU that was designed with the engineers assistance. The PSRU hasn't failed in several months.
Just a fact., nothing to do with my opinion. I would never suggest to anyone to build or fly in any multi-seat experimental with an unproven auto engine or PSRU.
 

rbarnes

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I meant the PSRU that was designed with the engineers assistance. The PSRU hasn't failed in several months.
Just a fact., nothing to do with my opinion. I would never suggest to anyone to build or fly in any multi-seat experimental with an unproven auto engine or PSRU.
Are we counting the dampener that shook every bolt holding it on loose as part of the PSRU ? I am ... this was just last month...

 

BBerson

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I suspect Peter created the weight specs himself, just wildly guessing without engineering being a part of it at all. Pretty sure he outright said he started with 1800 because that was what the Velocity was.
And you are just guessing about what happened.
 

BBerson

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Still, I can't agree that's it has worked fine. It has logged relatively few hours and has had several failures
I don't think the prsu failed more than once, perhaps a year ago. Again, I wouldn't be surprised if the prsu failed in the first minute of flight.
 
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