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lehpron
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Sonic Cruiser Needs Some Changes

Tue Sep 18, 2001 5:24 am

I personally feel Boeing is going in the wrong direction with this specific shape, so I have come up with a proposal based on what they have been doing all this time.

You can visit my first webpage to read a brief explaination and see an unfinished picture of what I am talking about that might help. All criticism is expected, thank you. Statistically,  Yeah sure, one of you should be impressed.

http://www.lehpron.homestead.com/one.html
The meaning of life is curiosity; we were put on this planet to explore opportunities.
 
lehpron
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RE: Aah, Wrong Page

Tue Sep 18, 2001 5:43 am

The meaning of life is curiosity; we were put on this planet to explore opportunities.
 
Ralgha
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RE: Sonic Cruiser Needs Some Changes

Tue Sep 18, 2001 7:10 am

Are you an aeronautical engineer?
09 F9 11 02 9D 74 E3 5B D8 41 56 C5 63 56 88 C0
 
lehpron
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RE: Sonic Cruiser Needs Some Changes

Tue Sep 18, 2001 7:49 am

Not yet. I'm majoring in aeronautical engineering right now. I've been doing stuff like this since junior high so it's no big deal to me.

Just a hobby I guess...
The meaning of life is curiosity; we were put on this planet to explore opportunities.
 
Mark_D.
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RE: Sonic Cruiser Needs Some Changes

Tue Sep 18, 2001 8:01 am


Lehpron

Well it may be that Boeing doesn't need as radical an airframe concept change for the SC, but y'know, proof's in the pudding. Trouble is there aren't even small military planes out there that are designed for that near-Mach cruise regime. And here Boeing comes along, and from scratch says it's going to make an airliner for 250-300 people, let alone what the fuel economics will turn out to be.

So, quite a radical announcement in itself, just as is.

 
777236ER
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RE: Aah, Wrong Page

Tue Sep 18, 2001 8:08 am

Oh boy, quite a few issues there....


Firstly, i think THE biggest problem will be transsonic drag, which will be HUGE where the SC is planning to fly at. I don't know how Boeing are going to counter that, unless they've got some sorta super-dooper aerofoil they're not telling us about.

You're design looks okay, but there are some problems. Firstly, it doesn't look too big for a 767-size airplane. Secondly, the aerofoil you're drawn looks more supersonic than subsonic, and although that would be magnificent at transsonic and supersonic speeds, landing performance would be AWFUL! Remember, Boeing wants to get this plane in and out of the same runways as current aircraft with similar landing/take-off speeds. If you're going to stick with that aerofoil profile, you need to lengthen the chord, significantly, and if you do that you almost end up with Boeing's design  Smile. Another problem is engines. Where are they? Pylons, like so many others? That would cause BIG problems at transsonic speeds, and semi-buried engines like Boeing's SC design has would be better.
You might want to look at the fin too. I haven't worked it out, but it looks at though the surface area MAY need to be bigger.

Canards and a twin fins are very useful for faster aircraft. Canards give you quite a lot of pitch control at higher speeds and depending on C of G, etc, they can significantly reduce drag compared to a standard stabilizor at the rear. Twin fins helps to maintain stability, especially near transsonic boundaries.

As you mentioned, the biggest problem for Boeing is that a lot of the stuff on the SC is new for them. They've never had twin fins, canards, embedded engines, but i'm sure that if they put their minds to it they can pull it off.

You're design still looks good though, well done!

ps. so you want to work at Boeing?  Smile I'd love to have CATIA and EPIC on my home PC. That would be SO COOL! Ah well, maybe one day...
Your bone's got a little machine
 
charlieduke
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RE: Sonic Cruiser Needs Some Changes

Tue Sep 18, 2001 8:47 am

Allow me to once again state my opinion that the Sonic Cruiser will in fact be a supersonic aircraft. Boeing has publicly stated that the artist rendering that they made public is not what the final version will look like, and that they have not ruled out a supersonic flight regime. That, combined with the drug and alcohol addled rumors of a former Boeing engineer who currently resides on Vashon Island (who will tell you anything you want to know for a bottle of Mad Dog) brings me to my conclusion. Don’t expect Boeing to own up to it until the RFP’s, RFQ’s and SOQ’s go out.
 
IMissPiedmont
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RE: Sonic Cruiser Needs Some Changes

Tue Sep 18, 2001 12:37 pm

Someone said the SC was designed by Boeing from scratch. Not quite. The basic SC design as shown so far is a McDonnell Douglas design project. Can I provide proof? No. Just have a little inside knowledge. If you doubt me, take a real close look at the nose.
The day you stop learning is the day you should die.
 
lehpron
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RE: 777236ER

Tue Sep 18, 2001 2:11 pm

Thanks dude, it is nice to see I can impress people with designs that even I have had problems coming up with.

Well this proposal is a continuing project and I just started it a few weeks ago so I don't expect it to be finished for a while. I purposely made it small for two reasons: 1) I am limited with how much space I can have since the webhost is free. 2) Like other 7x7's it has the nice "stretch" capability.

Secondly, the aerofoil I put in was purposely sharp to cut down the drag. It has a thick cross section by initial scale, as of landing performance, I will employ high-lift elements -- the plan is to make it as 777-like as possible

The problem with the engines is that at the time of the latest update, they have not been installed, I'll put them in by friday. And, yes they are semi-buried. As of the vertical fin, if we add the area on the current SC's double fins, it comes pretty close. I have not decided if there will be either canards or a tailplane -- operation may be similar to a Concorde.



Soon, Boeing might be the only place to work. Big grin I have Acadr13, but I screwed around with the program and it doesn't work anymore.

Thanks again, and to all of you who responded, keep in touch!  Smile/happy/getting dizzy
The meaning of life is curiosity; we were put on this planet to explore opportunities.
 
Boeing Nut
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RE: Sonic Cruiser Needs Some Changes

Wed Sep 19, 2001 1:21 am

Changes?!! The program is just in it's infancy. They wouldn't know what to change yet.
I'm not a real aeronautical engineer, I just play one on Airliners.net.
 
Mark_D.
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RE: Sonic Cruiser Needs Some Changes

Wed Sep 19, 2001 2:16 am

Charlieduke --Allow me to once again state my opinion that the Sonic Cruiser will in fact be a supersonic aircraft.

Sounds good to me, now we're talkin'. As introduced from Boeing, me I still can't get much past the lingering hokeyness of the 'near-Mach' cruise claims, not with any down-to-earth fuel consumption values attached anyway. But if it were in fact a supersonic craft, equipped with passable fuel and handling performance for high-subsonic transiting over Continental U.S., Western Europe, and very small strips of Asia, the Far East (and kinda everywhere else just let 'er rip, way above the sound barrier), then the concept makes a whole pile more sense to me.

Just that maybe too elitist-sounding and detractor-attracting, to come full out and market it that way right now.

I think you may be right!


(and you too, IMissPiedmont, SC does look kinda "DC-10/MD-11"-ey, way up front)

http://www.aworldaway.com/Images/20xx.jpg
 
777236ER
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RE: Mark_D

Wed Sep 19, 2001 2:27 am

The problem is, it's difficult to get two economical cruise speeds. Either 0.95 or 1.5 (for example) would be economical, but not both of them, which is the problem when the aircraft has two cruise speeds.
Your bone's got a little machine
 
Mark_D.
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RE: Sonic Cruiser Needs Some Changes

Wed Sep 19, 2001 2:45 am

777236ER -- the problem is, it's difficult to get two economical cruise speeds

Not to mention airframe designs as well, I agree. Still very much pulling a rabbit out of a hat. But less so, to me anyway, than if it's just gonna be 0.95 Mach, or thereabouts. Heck maybe it's just going to come out all supersonic, period, and that's that (just that they don't want to say, right now).

But cruise alone around .95 Mach, be making its own air pressure wall literally to push against, in that regime. I don't know how they're going to keep that going for a dozen or more hour long flight without burning a Space-shuttle External Tank's worth of fuel or something, in the process.
 
charlieduke
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RE: Sonic Cruiser Needs Some Changes

Wed Sep 19, 2001 3:29 am

I didn’t go into much detail in my previous post, but I will tell you a little more about what I have heard (remember, this is all second hand). The SC is going to cruise supersonic, even over land. There will be no m.98 cruise speed. That is just a ruse. The breakthrough was achieving supersonic laminar flow by non mechanical means. The laminar flow reduces the footprint of the sonic boom enough that the SC will be able to operate over land and maintain stage 4 compliance.
 
777236ER
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RE: Sonic Cruiser Needs Some Changes

Wed Sep 19, 2001 3:42 am

Remember, it is possible to go supersonic without a boom. (Well, without a boom audiable at ground level). An "M" shaped wing, (with the wing coming forward from the root, then near the middle sweeping back) tends not to have a large sonic boom. Hey, Boeing could still make the Sonic Cruiser live upto its name.
Your bone's got a little machine
 
lehpron
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RE: An "M" Shaped Wing

Wed Sep 19, 2001 6:21 pm

Hold up, I'm in serious shock, I thought I had 6 left, but now it's down to 5!!

An "M" shaped wing, (with the wing coming forward from the root, then near the middle sweeping back) tends not to have a large sonic boom

Do you mean a wing shaped like a gull wing in forward view or a top view like most birds during a power dive?

Where did youe see/hear/read about this?? I'd like to know as much as possible since I swear to god I came up with that idea during the months of August though November of 1996.
The meaning of life is curiosity; we were put on this planet to explore opportunities.
 
fatboy
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RE: Sonic Cruiser Needs Some Changes

Thu Sep 20, 2001 1:54 am

Lehpron-
Two aircraft immediately come to mind
http://www.dfrc.nasa.gov/PAO/PAIS/HTML/FS-019-DFRC.html
http://www.dfrc.nasa.gov/PAO/PAIS/HTML/FS-008-DFRC.html
I don't believe either one of them was specifically designed for the purpose of reduced sonic boom, but the principle has been understood for several years.

Question for charlieduke-what does laminar flow have to do with sonic booms? I'm not an aeronautical engineer, but I am pretty sure that the sonic boom is the result of the great pressure differential from front to rear, regardless of laminar flow.
 
777236ER
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RE: An "M" Shaped Wing

Thu Sep 20, 2001 2:20 am

Yes, the wing i'm talking about is like that. I think it can go to about Mach 1.4 (or maybe 1.7) without a boom audiable at groundlevel (Assuming 45000ft+). This was studied for Concorde among others, but I think there are serious drag and fuel worried. But hey, Boeing might be able to perfect this aerofoil. Remember, i'm no supersonic expert. Subsonic and lower/middle transonic is my thing. But if you work out the supersonic shock patterns for this wing it might show this to be true. Try to get a schlieren photograph of one of these wings. You might be able to find one at nasa.gov. They MUST have done some research onto these wings.
Your bone's got a little machine
 
Mark_D.
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RE: Sonic Cruiser Needs Some Changes

Thu Sep 20, 2001 2:26 am

Fatboy --Question for charlieduke-

Well I don't know either, but heck I'm happy to take his word for it at this point in time, since Boeing's revealed so little and, frankly, the SC being really an "SSC" does make a whole lot more sense to me.

About the techniques used --for drag reduction and possibly boom intensity mitigation as well-- maybe something along these lines

http://www.setv.org/online_mss/lafl-osr.html

(and this I guess might've been the one he was ruling out when he said "non-mechanical":

http://oea.larc.nasa.gov/news_rels/1996/Oct96/96_167.html

)
 
charlieduke
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RE: Sonic Cruiser Needs Some Changes

Thu Sep 20, 2001 3:10 am

Fatboy-

You are correct, laminar flow and sonic boom are not cause and effect, but they are related. For instance (again, remember I am not an aeronautical engineer either) by improving laminar flow to over, let’s say 90% of the wing surface, you have gained significant increases in efficiency. Now, what do you do with that efficiency? How ‘bout increasing wing surface, adding trailing edge devices, a blunt nose, or other well-know techniques for decreasing sonic boom? These techniques have not been employed in the past due to the associated drag penalties. But I believe that Boeing has changed the equation.
 
Alessandro
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RE: Sonic Cruiser Needs Some Changes

Thu Sep 20, 2001 4:04 am

So will the SC be able to land in foggy, rainy condition with gusty sidewind? Will it be able to fly and land without "electronic stilts"? Like the Mercedes A-klasse,
how good is it without "electronic stilts"?
From New Yorqatar to Califarbia...
 
777236ER
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Laminar Flow, "electronic Stilts" And The SC

Thu Sep 20, 2001 4:11 am

Re. Laminar flow -- Yeah, laminar flow could help, but the more laminar flow you aim for, the more difficult it is to maintain. For example, for really high laminar flow, even a squashed bug acquired during takeoff would disrupt it. But remember, it is possible to go above Mach 1 without any sonic boom audiable at ground level (can be upto Mach 1.5).

"Electronic stilts"? Are you implying that the SC will be unstable. I don't think so. If it uses Boeing's "gloved delta" it definatly won't be unstable and would be more stable than conventional jets. With other wings, well things change, but whatever happens the SC won't be that unstable.

Time will tell, but i personally think the SC will go above Mach 1, therefore eliviating troublesome transsonic drag that's found just below Mach 1. Actually, it may be more fuel efficient to fly faster than Mach 1 than just under Mach 1.

Regards.
Your bone's got a little machine
 
Alessandro
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RE: Laminar Flow, "electronic Stilts" And The SC

Thu Sep 20, 2001 4:21 am

I´m not in the airplane bizniz and don´t have great knowledge about airplane design, so if you claim it to
be more stable than "conventional" design, I buy that!
From New Yorqatar to Califarbia...
 
777236ER
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RE: Laminar Flow, "electronic Stilts" And The SC

Thu Sep 20, 2001 4:26 am

I don't know if it'll be more stable. I'm not an expert on supersonic flow, but it looks like it'll be more stable than most other fesiable supersonic designs. As lower speeds however, i'm not sure about LOW speed flight. Boeing's "gloved delta" should be okay, at slow speeds and have a VRef of about 20-30 kts higher than conventional planes.
Your bone's got a little machine
 
GDB
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RE: Laminar Flow, "electronic Stilts" And The SC

Thu Sep 20, 2001 5:07 am

A real in-depth, focussed and interesting thread! When I first saw the drawing of the BSC I thought 'that's a supersonic'.
I guess Boeing knew that the immediate objections would be sonic-boom, high fuel consumption at subsonic speeds, noise, high altitude pollution, all the objections lobbed at Concorde 30 years ago.
But by claiming it's Mach 0.98, the enviromentalists lose interest, the airline accountants don't scream and it gives Boeing more time to research and design, to get a better idea of whether it can be made to work.
They did need something to lift morale and for PR after 747X/767ERX got axed, but the BSC looks for real, and some of the informed postings on here confirm my belief that the aircraft is designed for the Mach 1.2/1.5 area.
If they can really can pull off stage 4 compliance 'booms', then it really makes sense, you don't want two cruise speeds, Concorde is very efficient at Mach 1.7 - 2.02, but before that, well you all know! Not to mention shorter journey times.
 
Alessandro
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RE: Laminar Flow, "electronic Stilts" And The SC

Thu Sep 20, 2001 5:23 am

Saw that Boeing is doing tests in windtunnel, so I guess
they will do their home work, 484 hrs with the Tu-144
will also help....
From New Yorqatar to Califarbia...
 
XFSUgimpLB41X
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RE: Sonic Cruiser Needs Some Changes

Thu Sep 20, 2001 6:14 am

I just get the idea that Lephron thinks he knows a whole lot more than he really does....
Chicks dig winglets.
 
lehpron
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RE: Sonic Cruiser Needs Some Changes

Thu Sep 20, 2001 6:27 pm

I just get the idea that Lephron thinks he knows a whole lot more than he really does

 Embarrassment Golly. You know it could be vice versa. Big grin

Don't ask me how, but other than this SC_V2.0, I just have this gut feeling that something will change for the better in this field and I'll be spear heading us into the future. I don't think much about this "SC_V2.0" because I consider the original Boeing concept to be subsonic -- I hate subsonics mainly because I can't draw them very well and it is not my expertise.

My realm is in supersonics and hypersonics, and I will make one before I retire. Again, don't ask me how, yet.

Be sure to check back for updates around Saturday.

Peace out,

lehpron
The meaning of life is curiosity; we were put on this planet to explore opportunities.
 
lehpron
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RE: Update!

Sat Sep 22, 2001 11:26 am

I've added the engines on the side view and a new a top view, the section lines for the flaps has not been added.

The inboard wing will be have a standard 4-element airfoil and outboard will have two pairs of elevons.

http://www.lehpron.homestead.com/two.html

All comments/criticism are accepted, hope you
like 'em,  Smile/happy/getting dizzy

lehpron
The meaning of life is curiosity; we were put on this planet to explore opportunities.
 
Areopagus
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RE: Update!

Sat Sep 22, 2001 3:45 pm

OK, it looks attractive, but what are you going to do about wave drag? Your airplane is very lumpy in its cross sectional area profile. Go to http://history.nasa.gov/SP-367/chapt5.htm
and look for "area ruling".

What do you mean when you say about the Sonic Cruiser, "Such features as the double-delta wing has no purpose"? Of course it has a purpose. It allows a thick wing root to have a low thickness/chord ratio, much like the Handley-Page Victor's crescent wing. Plus, it smooths out the area distribution, reducing wave drag. Furthermore, it holds loads of fuel needed for long range.

You say, "Shape is too extreme, all moving canards and twin rudder fins?" So? Was the Constellation too extreme for having three fins? The canard may be unusual, but it is part of the solution to the problem of beating wave drag with a constant-section fuselage.

IMissPiedmont says:
"The basic SC design as shown so far is a McDonnell Douglas design project. Can I provide proof? No. Just have a little inside knowledge. If you doubt me, take a real close look at the nose."

I refer you to the Boeing 307 airliner. See http://www.aviation-history.com/boeing/307.html
 
lehpron
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RE: Areopagus

Sat Sep 22, 2001 6:24 pm

I'll calculate the area ruling on the body and see what happens.

When I wrote "Such features as the double-delta wing has no purpose," I was talking about the shape. All subsonics ,including Boeing aircraft, have had swept wings with a maximum of 40-degrees. Wings with sweeps past 45-degrees form their vortices on top of the wing rather than at the tip, like Concorde.

"Engineers will have to be careful about vortices from the swept glove hitting the tails, which caused structural problems on the McDonnell Douglas F/A-18." (Dornheim, AW&ST Apr 2, 2001)

In my mind, I see this more dangerous than if it came out at the tips. There had been discussions in the Tech/Ops (https://airliners.net/discussions/tech_ops/read.main/23128/) about airliners that can approach the speed of sound without a sharply swept wing, Check it out.

As of "Shape is too extreme, all moving canards and twin rudder fins?," you missed my point. I like extremes, it is just that Boeing has never done it before and the last time they tried it, they dropped the project. Remember, Boeing is DPH bigtime. The best way to cut costs is to quite literally make the same plane over again but better -- hence new airplane with new market.

Also, for those who claim SC is supersonic, Boeing withdrew from the HCST project with NASA in 1999 after a market poll told them that passngers aren't willing to pay more to go faster, why then would they go off and make their own high speed civil transport which will cost more to passengers?
The meaning of life is curiosity; we were put on this planet to explore opportunities.
 
GDB
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RE: Sonic Cruiser Needs Some Changes

Sat Sep 22, 2001 6:46 pm

The HSCT was mainly dropped because Boeing could not make the enviromental (noise/emissions) figures work for stage 4 and beyond.
And the boom would have been too great for overland flight, maybe with smarter aerodynamics and a much lower Mach number they could pull it off with the SC.
However, we'll have to see how they plan to modify exsisting high-bypass engines if they are serious about a supersonic SC.
An all-new engine would kill the project due to costs.
 
Areopagus
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RE: Update!

Sun Sep 23, 2001 2:58 am

'When I wrote "Such features as the double-delta wing has no purpose," I was talking about the shape. '

And I pointed out that the shape has a purpose. As does Dornheim in the article you cite.

'"Engineers will have to be careful about vortices from the swept glove hitting the tails, which caused structural problems on the McDonnell Douglas F/A-18(Dornheim, AW&ST Apr 2, 2001) '

Dornheim also wrote, "The claimed range of 9,000 plus naut. mi. at Mach 0.95 strains credulity," and "The public evidence that this [L/D of 15-16] is achievable at Mach 0.95 is sketchy at best." But Boeing seems to be very confident that they can pull a rabbit out of their hat. MD is now in the Boeing fold, so the F/A-18 engineers presumably can consult on this. I have to assume that Boeing's engineers are looking at all the objections we think of, including what bugs and feathers on the leading edges do to its aerodynamics. (Still, we can in retrospect point to problems with other airliners that the engineers should have considered.)

About airliners that can approach the speed of sound without a sharply swept wing: well, there is a big difference between doing that in a dive, and doing it economically over long ranges.
 
777236ER
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RE: Update!

Sun Sep 23, 2001 4:27 am

A number of points: with that design, as someone mentioned, you'd need area ruling -- which is annoying as it cuts floor space. The wing is interesting, but it has problems. Outboard of the engines the chord needs to be VASTLY greater, and the chord of the whole wing needs to be bigger if you are going to have no stabiliser. Another point, why no stabiliser? I could understand if this was Mach 1.5+, but it isn't. A canard at the front would alieviate big balancing and stability issues, with, if anything, a reduction in weight (due less amount of wing area needed). With elevons, are you're suggesting, they'd need to be full-span to be of any use, not just inboard of the engines.

BTW, Boeing are looking to use 95000lb engines (ie. 777 engines) so the air intake would have to be a LOT bigger and the engines should be of a regular shape.
Your bone's got a little machine
 
lehpron
Topic Author
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RE: Sonic Cruiser Needs Some Changes

Sat Sep 29, 2001 3:29 pm

Fatboy-- I saw those NASA websites, I've seen the scissor wing concept before and I read that they act as if the air is traveling subsonic over the wing even when the plane is supersonic.

Aeropagus-- I figured out a temporary area ruling and it looks like half a oval, how is it lumpy, especially since I haven't posted up a forward view? Maybe later I'll post my findings here for all of you.

777236ER-- There is no stabilizer, as an extra plane, because 1) it would make the design look ugly and 2) I wouldn't know where to put it. Besides, isn't there a subsonic British bomber that also does not have a tail/foreplane?

My guess on inlet size is based on the fact that there is a whole LOT of air in front of the plane as it approaches the speed of sound (i.e. density of airflow @M0.98 is higher than traveling at M0.85, once thespeed of sound is pasted the air is now compressed). So I figure a small inlet would give the same airflow density as a larger one. Since you know more about trans/subsonic flow, you can correct/back me.

Thanks y'all, keep it coming! Big grin

lehpron
The meaning of life is curiosity; we were put on this planet to explore opportunities.
 
lehpron
Topic Author
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RE: 2nd Update: Aerofoil, Engine, And New Views.

Tue Oct 02, 2001 5:32 am

Rather than make you leave Airliners.net, all new pix 'n info are here. I hope you are enjoying this as much as I am. Big grin

First of all, as someone stated, the inlet did need to be bigger. I found out that the inlet I put in was with respect to wing root and not where the inlet actually was. To allow greater airflow at low speeds, a retractable vent was added to the top-forward section of engine housing. The engine fan diameter was calculated to be approximately between 88 and 90 inches, so I drew in a fake engine for representation. I also put in a view with a Pratt & Whitney 4000 series engine to see if it would fit, and sure enough, it did (check out fig. #1).

Figure 1



Figure 2


You guys must have already noticed by now that on the updated top/side view (fig. #2), those look like pretty large flaps, huh? Well there’s a simple explanation, since the wing was already thin and I wanted to have a multi-element aerofoil with high lift devices, I had to basically invent a new aerofoil (fig. #3).

Figure 3


It has a standard slat and main aerofoil but the main flap has its own secondary flap; there was no room for a vane. This led to problems of naming and since I have never seen this type of configuration, I can only predict how it will respond. Figure #4 shows a predicted boundary layer behavior for this multi-element aerofoil.

Figure 4


You also may have noticed that there is an estimated coefficient of lift equal to 1.18. This was found through calculation rather than actual testing. This plane’s outboard wing is similar to most subsonic airliners, at sea level; their coeff of lift is about 1.7. In inboard wing is closer to Concorde’s delta though not as steeply angled, its coeff of lift at sea level is about 0.68. I then took an average based on wing area; X coeff times out board wing plus Y coeff times inboard wing divided by total area. It is crude, but I do not have any professional equipment nearby to attain accurate data.

* * *
And yes, there still is no stablizer, I am thinking of close-coupled canards placed directly in front of wing to reduce drag. I am also investigating the effect the slat has on airflow around the engine intake. I hope this concept/design is starting to make a little more sense to you guys now, again is you have any questions/comment/corrections, be all means go for it, okay?

lehpron
The meaning of life is curiosity; we were put on this planet to explore opportunities.
 
777236ER
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RE: 2nd Update: Aerofoil, Engine, And New Views.

Tue Oct 02, 2001 5:53 am

Wow. Ok, here we go.

(BTW, i'm interested in wings. I'm going to avoid the engines)

Firstly, I still think the whole wing profile is wrong. Chord outboard of the engines needs to be a lot bigger. At the moment, I think total lift coefficient isn't going to be near your value with the current outboard section. Remember, outboard you're keeping similar cross-section as inboard, so lift coef' will be less than 1.7.

Secondly, your high lift devices -- URGH! The slats really need to be more traditional. The hinged type you've chosen are awful. Maybe even Krueger flaps inboard of the engines? The slotted flaps are good enough, but multi-slotted Fowler flaps would be better, especially if you want slow landing/take off speeds. Although the Fowler flaps may have a large weight penalty, so the slotted flaps may be the best options.

The wing section itself....i'm not sure :S. Remember, we're not going THAT fast, but we are in a lot of transsonic drag in this region (which is why i think the SC will become the SSC  Big grin) so your wing might NEED to be that thin to be anything like efficient, but then you'll encure landing/take off speed restrictions that no high-lift devices can compensate for.

Stablizer.....stablizer....... Smile You really do need one, or do some major wing work. With no stablizer you really need elevons, so flaps are out.

But all in all, good job! Love the engine. Even though it's not my field, won't transsonic airflow be too fast for the engines to handel? Surgey surgey!  Smile

Well done.
Your bone's got a little machine
 
lehpron
Topic Author
Posts: 6846
Joined: Tue Jul 10, 2001 3:42 am

RE: Sonic Cruiser Needs Some Changes

Tue Oct 02, 2001 6:28 am

I'll respond in reverse just for you, 777236ER Big grin

Yes, no jet engine in the world can take airflow approaching/passing the speed of sound, that is why there is a great distance from inlet to engine face. Most engines perform their best with fan face airspeed @ around 400mph (?). Most airliners have 2-3 ft. of separation from inlet to fan. Concorde has 15ft! That's because the air becomes compressed, but we already have a compressor onboard, overcompression would cause the engine to pop like a balloon.

Like I said, I think I'll put in close-coupled canards as the stablizer, like on an X-29; that's why the secondary flap is how it is, so it can operate as a high speed elevator as speeds approach 650 mph @ alt.

As of wing's thinness, remember I am trying to think like Boeing, with drag reduction obcession and DPH on the brain.  Smile As of high lift devices, I looked at all of them, thought of something in between a single or double slotted flap, and found out all the hinge machinery would spike up the drag. I might as well make the wing thicker, but you know, same reason as above.

I still think the whole wing profile is wrong

Good for you, I still like the wing  Smile

Besides, if you look closely at the pictures that Boeing has on their site about the SC, their wing is 1) just as thin and , 2) minus the delta glove and twin fins , looks just like this form. I didn't entirely make it up.

Also, I recalculated the CL and I came up with 1.088, I hope it doesn't keep going down, but then I didn't take the high lift devices into account.

Keep 'em coming you guys.

lehpron
The meaning of life is curiosity; we were put on this planet to explore opportunities.
 
777236ER
Posts: 12213
Joined: Sat Aug 18, 2001 7:10 am

RE: 2nd Update: Aerofoil, Engine, And New Views.

Tue Oct 02, 2001 6:47 am

Well! I was put in my place wasn't i?!  Smile

I still don't like the wing  Laugh out loud

A control point just hit me. With the high-lift devices, you're going to need spoilerons to get a decent roll rate. One outboard aileron isn't enough.

Regards.

777236ER -- The Campaign For Greater Chord in Wings (CGCW)

Your bone's got a little machine
 
Areopagus
Posts: 1337
Joined: Thu Sep 20, 2001 12:31 pm

RE: Sonic Cruiser Needs Some Changes

Wed Oct 03, 2001 2:20 am

I figured out a temporary area ruling and it looks like half a oval, how is it lumpy, especially since I haven't posted up a forward view?

Well, it partly depends on how your engines match the reducing thickness of the wings, which is hard to judge from the drawing. The engine inlets appear to begin at wing's greatest cross-sectional area. What strikes the eye is that the engines are located alongside the constant-section fuselage, and end where the fuselage starts to taper. In contrast, current-generation twins put their engines largely ahead of the wing, or aft of the wing, as in the 717 and the Mach 0.92 Cessna. The BSC engines overlap the wings, but their area rise matches the rear fuselage taper.

777236ER-- There is no stabilizer, as an extra plane, because 1) it would make the design look ugly and 2) I wouldn't know where to put it. Besides, isn't there a subsonic British bomber that also does not have a tail/foreplane?

That would be the Vulcan. Its elevons are at the extreme aft end of the airplane. Your elevons don't have a very long lever arm on which to act as elevators.

 
lehpron
Topic Author
Posts: 6846
Joined: Tue Jul 10, 2001 3:42 am

3rd Update: I Changed It, Slightly

Mon Oct 08, 2001 6:56 pm

Well after some serious revisions, the aircraft has been changed, somewhat. The fuselage has been waisted, the main wing was move back, a small gloved delta was added to the wing root, a pair of canards was added, and the vertical tail was made larger for stability.



Why was the fuselage waisted? This was a consideration of both the airflow density as the Vmax approaches M1.0 and the area rule. Calculating the area rule ruined the original.

Why are there two canard pairs? The original purpose of the delta gloves was actually the planned close-coupled canards (ccc). There were pitch errors so a second pair was added to nose, then ccc was made part of wing.

What's up with the cockpit windows? Well this is my own creation (whether or not it already exists is not my problem simply because I was never aware of it). Here, instead of large sreens like in NASA's concept, virtual reality headsets are directly connected to cameras outside. I called it the Spycam System back in 1996 when I first came up with it.



Also I have already checked to see if this wheel arrangement will fit into the fuselage when they retract. If you guys would like more explaination, go back to my site:

http://www.lehpron.homestead.com/two.html

------
As always, tell me how I did or critique me (most people prefer the latter I see). A few reply, what about the rest of you, what are you thinking?
The meaning of life is curiosity; we were put on this planet to explore opportunities.

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