10/23 Raptor Video

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Turd Ferguson

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The "complete kit" in aviation started 44 yrs ago with introduction of the Christen Eagle. Every part shrink wrapped onto a cardboard background, numbered and/or labeled, with corresponding documentation in the assembly manual(s). But complete kits such as those are not for everyone.

I like Patey's projects but can't escape the fact to reach that level of 'overperfomance' a 7 digit budget is extremely helpful.
 

Richard Schubert

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I met a traveller from an antique land, Who said—“Two vast and trunkless legs of stone stand in the desert. . . . Near them, on the sand, half sunk a shattered visage lies, whose frown, and wrinkled lip, and sneer of cold command, tell that its sculptor well those passions read which yet survive, stamped on these lifeless things, the hand that mocked them, and the heart that fed;
And on the pedestal, these words appear: My name is Ozymandias, King of Kings;
Look on my Works, ye Mighty, and despair!
Nothing beside remains. Round the decay of that colossal Wreck, boundless and bare, the lone and level sands stretch far away.”
 

flywheel1935

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The "complete kit" in aviation started 44 yrs ago with introduction of the Christen Eagle. Every part shrink wrapped onto a cardboard background, numbered and/or labeled, with corresponding documentation in the assembly manual(s). But complete kits such as those are not for everyone.

I like Patey's projects but can't escape the fact to reach that level of 'overperfomance' a 7 digit budget is extremely helpful.
On my first visit to the States in 1979, (to see the Air Racing at Reno), I then arranged to meet Burt Rutan at Mojave and Frank Christensen in Hollister, and yes
I agree that his kit, that included the blade to open the boxes was the first true A-Z Aircraft build, (as per Caterham Cars).
And yes I did see Steve Hinton crash the Red Baron, and also met John Crocker who won that year. Ah, the 'good old days'.
 

ImperfectSense

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So then am I understanding these recent posts correctly, PM and Raptor are NOT at Oshkosh... and the Raptor program has somehow been officially ended???
Not sure where you got either of those impressions. Raptor is not at Oshkosh but iirc Peter planned to go. And afaik Peter still believes Raptor is going to be acquired/completed by a mysterious west coast company.
 

HomeBuilt101

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Here is an interesting video on adapting auto engines for aviation use (geez even Toyota was not successful):


PM is not the first person to attempt to use a car engine in an airplane. My guess the reason why he worked so hard on making the Audi engine a success is the future need for Jet A or diesel and the concept of the "always on anti-ice" leading edge radiators and those need to have liquid cooling.

He bit off a lot to chew at one time...new airplane design...auto engine conversion...pressurization...high tech EFIS...high altitude and super long range expectations.

I still think the very basic concept is a good one. The airplane looks nice, it is a good size (5 seats is perfect for the family with 2.3 children). The Velocity "Dash 5" has a bench seat in the back but that is only good for two adults or three smallish people but the Raptor is a true 5 adult airplane.

Using molds to create the composite parts seems a great deal more "modern" and labor efficient than carving foam cores out of a big block of foam using a hot piano wire and wood templates ("approaching 2...approaching 3...approaching 4...etc.") then the laying out wetted BID on top of the foam core and all of the "micro-epoxy" slurry and sanding. That is a great deal of work and presents a huge health hazard in the work place and the associated waste of materials. The molds would allow for very accurate and stable parts and the vacuum bag process would squeeze out the epoxy making for light weight parts... all of that sounds really good.

So why is the Raptor so heavy?

Yes it has thick windows and thick fuselage walls...and metal thick plates used to reinforce the aileron pulley support structure...and air-conditioning...and an automotive heater core mounted up front with the associated 30 feet of heater hose...ohh I forgot the propeller redrive and Audi engine (does it have an aluminum block or cast iron).

Is the same part made out of fiberglass the same weight as carbon fiber? What if the exact same airplane was made out of molded fiberglass parts as opposed to molded carbon parts...what would the weight reduction be? Then get rid of all of the thick glass and air-conditioning and all of the other "stuff" and redesign it more conventional like the Velocity.

What is the weight difference between a foam core fiberglass layup and a molded fiberglass parts all glued together with hollow wings?
 

rv6ejguy

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So funny...after that post I was watching some YouTube videos and guess what popped up...Great comparison of the Raptor verses Dark Aero
THANKS Ross!!!

This was more of an exploration of Dark Aero itself than a comparison to Raptor as they are targeting completely different markets. Viewers can compare how the two were designed and built though and that's markedly different. Dark Aero has yet to prove its performance projections at this time and no doubt experience with the prototype will result in some changes for production. We'll have to wait a bit to see how this all shakes out in a year or so after it flies and lessons learned are applied.

It's always risky IMO to make performance projections on new designs before flight proven however I'll go out on a limb and say that DA will be a lot closer to its than Raptor was.
 

Turd Ferguson

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Here is an interesting video on adapting auto engines for aviation use (geez even Toyota was not successful)
I guess it depends on one’s definition of success. Toyota has a type certificated airplane engine. I’d call that a success. They made a business decision to shelve it.
Ultimately, I think they also wanted an airframe to go with it but that’s a tough order. Even more so than the engine. What would be the best option? A Cirrus clone?
 

rv6ejguy

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The Austro, Thielert and Continental diesels are all automotive based. The only other auto engines I can think of used in large quantities are VW and Subaru, the latter used on many hundreds of RAF and some other gyro designs.

The engines are generally reliable if reliable supporting systems (fuel and ignition, PSRU, cooling and oiling) are installed.
 

BoKu

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...What if the exact same airplane was made out of molded fiberglass parts as opposed to molded carbon parts...what would the weight reduction be?...
The weight reduction would be negative. For equivalent strength or stiffness, a molded carbon part will almost always be lighter than its fiberglass counterpart.

As an example, I originally designed the HP-24 as a fiberglass sailplane with carbon fiber spar caps. My mass estimates, based on material content and similar sailplanes, suggested that the empty weight would be around 525 lbs ready to fit out. When we switched to an all-carbon structure, the first kit-standard glider turned out to weigh 439 lbs with all instruments plus battery and 24 ft^3 oxygen bottle and regulator.

...What is the weight difference between a foam core fiberglass layup and a molded fiberglass parts all glued together with hollow wings?
That's a bit less clear cut. Conventional wisdom is that moldless foam core is lighter than sandwich skins up to a chord of about 3 feet. However, the weight advantage isn't all that great, and sandwich skins are much more convenient in series production. Also, it's difficult to use carbon with moldless foam core.
 
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Victor Bravo

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Toyota had an airframe for their engine, the Lima, built at Scaled Composites. I saw it in person, and met the test pilot (Doug Shane). Looked somewhat similar to the Cirrus in shape. Doug was under a strict NDA to not even acknowledge that it was sitting there next to us !
 

WINGITIS

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Toyota had an airframe for their engine, the Lima, built at Scaled Composites. I saw it in person, and met the test pilot (Doug Shane). Looked somewhat similar to the Cirrus in shape. Doug was under a strict NDA to not even acknowledge that it was sitting there next to us !
Toyota had some airfoils commisioned as well....with a Patent, an interesting concept in itself!



 

Wanttaja

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Toyota had an airframe for their engine, the Lima, built at Scaled Composites. I saw it in person, and met the test pilot (Doug Shane). Looked somewhat similar to the Cirrus in shape. Doug was under a strict NDA to not even acknowledge that it was sitting there next to us !
Decades ago, a co-worker and I flew to LA for a meeting at Edwards. As our appointment was late in the day, we decided to go to Mojave to kill time. In addition to working with him, Mike was my co-owner in a Stinson.

This was pre-9/11, so the flight line was wide open. We walked by looking into the hangars, including Scaled. As we came around one corner, we saw a tractor composite airplane that wasn't familiar to either of us.

I shot a few pictures through a chain-link fence. We stepped inside the Scaled office and I asked to see their PR person. Gave her one of my Kitplanes business cards, and asked about the plane. "Proprietary," was all she would say.

It was, as it turned out, the Rutan Lima.
Lima2-1.jpg
Turns out, also, that there are apparently VERY view pictures of this airplane (other than the ones Scaled took for its records). So I got a gen-u-wine scoop.

My camera was just a little point-and-shoot (film), and I positioned it to put the lens clear of the chain links of the fence. Also backed off slightly to INCLUDE the chain link. Kitplanes' editor went with the with-chain-link image, I think to dramatize the heavy secrecy behind the development. Flight magazine in England also printed one of my shots, but they used the one without the fence showing.

Ron Wanttaja
 

wsimpso1

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Using molds to create the composite parts seems a great deal more "modern" and labor efficient than carving foam cores out of a big block of foam using a hot piano wire and wood templates ("approaching 2...approaching 3...approaching 4...etc.") then the laying out wetted BID on top of the foam core and all of the "micro-epoxy" slurry and sanding. That is a great deal of work and presents a huge health hazard in the work place and the associated waste of materials. The molds would allow for very accurate and stable parts and the vacuum bag process would squeeze out the epoxy making for light weight parts... all of that sounds really good.
While molded parts seem more modern, one of the interesting things is that the break-even point on weight between "massive core" and hollow structures is chord of about 2m. Massive core is lighter than hollow until chord reaches somewhere around 6.6 feet. We have talked about it before:
  • The hollow wing must have either:
    • Cored skins with about the same amount of outside skin, a foam core, then another layer of composite on the inside or;
    • A much thicker composite skin;
  • Then ribs with flanges, glue lines, etc.
All that stuff weighs more than the massive foam core until the chord gets pretty big.

Is the same part made out of fiberglass the same weight as carbon fiber? What if the exact same airplane was made out of molded fiberglass parts as opposed to molded carbon parts...what would the weight reduction be? Then get rid of all of the thick glass and air-conditioning and all of the other "stuff" and redesign it more conventional like the Velocity.
Carbon Fiber Composites are around 10% lower specific gravity than Glass Fiber Composite using same processes. Graphite based composites are anywhere from several times stiffer and several times stronger too, so you can use a lot less of it to achieve similar strength and/or stiffness. That is really where the weight reduction comes from.

What is the weight difference between a foam core fiberglass layup and a molded fiberglass parts all glued together with hollow wings?
WEIGHT IS THE ENEMY in all things that fly. You are on the right course with the question. Please use the Advanced Search tool to find and read the many posts and threads already in existence on just this forum to grow your knowledge on this. Then we can revisit this idea of some process making better airplanes.

Billski
 

WINGITIS

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While molded parts seem more modern, one of the interesting things is that the break-even point on weight between "massive core" and hollow structures is chord of about 2m. Massive core is lighter than hollow until chord reaches somewhere around 6.6 feet. We have talked about it before:
  • The hollow wing must have either:
    • Cored skins with about the same amount of outside skin, a foam core, then another layer of composite on the inside or;
    • A much thicker composite skin;
  • Then ribs with flanges, glue lines, etc.
All that stuff weighs more than the massive foam core until the chord gets pretty big.



Carbon Fiber Composites are around 10% lower specific gravity than Glass Fiber Composite using same processes. Graphite based composites are anywhere from several times stiffer and several times stronger too, so you can use a lot less of it to achieve similar strength and/or stiffness. That is really where the weight reduction comes from.



WEIGHT IS THE ENEMY in all things that fly. You are on the right course with the question. Please use the Advanced Search tool to find and read the many posts and threads already in existence on just this forum to grow your knowledge on this. Then we can revisit this idea of some process making better airplanes.

Billski
When its not structural and if it were to be mass produced one could consider the General Motors SMC process/products, I believe(Not confirmed) they started doing that on the C3 Corvette back in the sixties and certainly the C4's of the eighties.

Here is an article on the next generation of SMC's used for the C5 Corvette from 1998:

 
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