Celera 500l Progress

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autoreply

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Rotterdam, Netherlands
I think they were saying 250 mph so 217 knots at 15,000 feet. I can't see that small prop being very efficient at 50,000 feet and 450 mph. Available thrust is a tiny fraction of static thrust at that speed.

In the real world, a few dozen bug splats will negate much of the laminar flow.

I'm certainly impressed with what they have done so far and it's really thinking outside the box. Wishing them the best of luck here as they head towards certification and production. Even if they fall short of their projections somewhat, it will still be impressive and interesting to see how they do all this technically.
That's what bug wipers are for. They work just fine in real-world environments. Rain and icing are the only (temporary) exceptions ;-)
 

rv6ejguy

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Calgary, Alberta, Canada
NASA and other players were involved with several very high altitude projects starting in the late '70s- ERAST, Perseus, Teal Rain, Strato 2C etc.Below is why I don't think this engine will ever see 3 stage turbos on it:

Look at how large the first stage compressor is on this Rotax 914- 20 inches OD! and look at the weight and size of HXs. The RED would need even larger components since each bank is over twice the displacement of the 914 Rotax. Look at the weight of this monstrosity!

rotax3.jpg
rotax4.jpg
This is a poor quality photo but check out the size of the components. 7.5 inch compressor wheel is HUGE.

I think few people without an extensive turbocharger background appreciate the technicalities here. Judging from the size of the turbos shown in the RED renders, I'd say they don't- yet. I went on about this in the Raptor 2 stage critique and my video on staged turbos. Lots of lay people questioned it all. This ain't trivial or easy.
 

speedracer

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Feb 4, 2020
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At the R.A.C.E. (Rutan and composite enthusiasts) races the racers would launch at 20 second intervals and follow the leader to 1,000' AGL. Then the heat would line up horizontally for the start above the airport. At one race at Jackpot, NV. the starter, Klaus Savier led us over an alfalfa field. I, and everyone else had never seen so many bug splats on our canopies ever. The speeds for that race were 10 MPH slower than normal.
 
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poormansairforce

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Mar 28, 2017
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Just an Ohioan
NASA and other players were involved with several very high altitude projects starting in the late '70s- ERAST, Perseus, Teal Rain, Strato 2C etc.Below is why I don't think this engine will ever see 3 stage turbos on it:

Look at how large the first stage compressor is on this Rotax 914- 20 inches OD! and look at the weight and size of HXs. The RED would need even larger components since each bank is over twice the displacement of the 914 Rotax. Look at the weight of this monstrosity!

View attachment 118446
View attachment 118447
This is a poor quality photo but check out the size of the components. 7.5 inch compressor wheel is HUGE.

I think few people without an extensive turbocharger background appreciate the technicalities here. Judging from the size of the turbos shown in the RED renders, I'd say they don't- yet. I went on about this in the Raptor 2 stage critique and my video on staged turbos. Lots of lay people questioned it all. This ain't trivial or easy.
This is priceless!!! Thanks for digging that up.
 

Kyle Boatright

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Nov 11, 2012
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1,344
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Marietta, GA
Why would Otto Aviation block their flight data on Flight Aware?
They are trying to keep a low profile. Notice that nobody was even aware of the airplane until it showed up on a ramp somewhere.

They seem to be following the "Build it, then market it" model, rather than the "market it, then built it" model.
 

Wanttaja

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Sep 15, 2013
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Seattle, WA
Yeah, it is scary (sobering?) to enter your N-number into flightaware and have it pull up your name and all of your recent flight tracks and times.
I operate ADS-B in anonymous mode just because it is no one’s business when, where, or how I fly.
I used to feel that way. Until I got a call, late in the evening, from the wife of an EAA chapter member. He'd gone out for a flight that day, and hadn't returned.

Put his N-Number into Flightaware and found where his track terminated. Sheriff found the wreckage and his body a short while later. Don't know if they'd used the ADS-B data. From the ADS-B track, one is able to see where he'd deviated from his course home, probably due to weather. Believe I posted about this in the "Crashes in the News" thread.

But I realized that should I ever run into trouble, my friends would at least be able to verify that I had landed somewhere, even if conditions kept me from phoning in. And if my track terminated away from an airport, folks would have a lot better indication as to where I was without having to wait until the FAA looked at it.

So I took my ADS-B out of anonymous mode.

Ron Wanttaja
 

rv6ejguy

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Calgary, Alberta, Canada
It seems from the articles that Celera will soon be fitted with the 2 stage RED engine for higher altitude testing and I have to think it is the test bed for RED to develop this version of their engine for altitudes above 25,000 feet. New engine fitted to new airframe. That often hasn't worked out too well in the past. We'll see how that goes.

I believe their stated production timetable is very optimistic given the new engine, airframe and altitudes Celera is supposed to perform at. I don't think the FAA will be so easy to satisfy especially with anti icing, fuel gelling and pressurization safety concerns with a single diesel engine.
 

sanman

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Feb 24, 2021
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239
It seems from the articles that Celera will soon be fitted with the 2 stage RED engine for higher altitude testing and I have to think it is the test bed for RED to develop this version of their engine for altitudes above 25,000 feet. New engine fitted to new airframe. That often hasn't worked out too well in the past. We'll see how that goes.
It's too bad that RED engine doesn't have that SkyActiv / SCCI type of piston tech, because it operates with a lower compression ratio, which would help in lower pressure conditions.

I believe their stated production timetable is very optimistic given the new engine, airframe and altitudes Celera is supposed to perform at. I don't think the FAA will be so easy to satisfy especially with anti icing, fuel gelling and pressurization safety concerns with a single diesel engine.
They're supposed to be able to work on JetA and biodiesel, right? Usually winterized diesel has additives that prevent gelling at cold temperatures. Sounds like the biodiesel was just mentioned to make it sound more eco-friendly, since everybody seems to hate jet aircraft as fuel hogs these days. They even mention possible electric/hybrid variants on their website.
 
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qchen98

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Oct 8, 2021
Messages
110
Why couldn't they circulate diesel in a heat exchanger, similar to the one on the Raptor?

If it is designed properly like the raptor, heated diesel that circulates all over the aircraft could remove icing, as well as heat the cabin at FL500.
 
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