RussianJet
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Why Are All Bizjets Rear-Engine/T-Tail?

Tue Apr 17, 2012 6:16 pm

Ok, may be a very basic question, but cards on the table - my knowledge of these things is not deep.

Seems to me that basically all small-medium bizjets are rear-engined with either a t-tail, or in Dassault's case a sort of 'cross' tail (which, btw, I think looks beautiful). What are the main reasons for this? I think a tiny jet with engines slung under the wing would look cool, but is such a thing feasible? Are there any examples in existence?

Is it principally a question of small wing needs to be a clean wing?

Grateful for any thoughts.
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KPWMSpotter
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RE: Why Are All Bizjets Rear-Engine/T-Tail?

Tue Apr 17, 2012 6:34 pm

Quoting RussianJet (Thread starter):
I think a tiny jet with engines slung under the wing would look cool, but is such a thing feasible? Are there any examples in existence?

It may look cool, but think of how much taller the plane will need to be in order to fit a pair of engines under the wing. Landing gear is heavy - very heavy, the closer you can keep a jet to the ground, the better. Also, most business jets don't have the option of connecting to a jet bridge, keeping the plane low saves on the complexity of the airstairs that need to be built into the door. The T-Tail or cruciform tail configuration is a result of the tail mounted engines; you don't really want your horizontal stabilizer to be continuously in the wake of the engines and jetwash.

The real question is "why aren't more airliners rear-engined and T-Tails?" The answer there is more a function of fuselage length. The fuselage between the engines and the wings needs to be reinforced to carry the thrust and weight load of the engines. With short, stubby business jets that doesn't add up to much weight. A 757 or 737-sized airliner would need to be significantly reinforced. Douglas made the configuration work, but most large aircraft are better off with the engines on the wings, which are already the strongest part of the aircraft.

VFW-Fokker tried a "best of both worlds" approach with the engines on top of the wings on the VFW-614, Honda is now experimenting with the same thing with the Honda Jet. This keeps the airplane low, and the engine loads on the wing, but for some reason the configuration really hasn't caught on.

Hope this helps!
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Pihero
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RE: Why Are All Bizjets Rear-Engine/T-Tail?

Tue Apr 17, 2012 6:39 pm

Two main advantages :
- The aircraft can sit lower, making shorter gear possible, needing shorter integrated airsteps, therefore saving quite a lot of weight.
The servicing is also mader easier, everything being at man-level.
- The wing is a lot cleaner, aerodynamically speaking

Add to these two :
-Generally speaking, the engines are protected from FOD
-The vertical stabilizer and the rudder could be designed smaller as the engines'thrust lines are close to the aircraft centerline ( an engine--out moment is smaller than on underwing-slung engines.
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vikkyvik
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RE: Why Are All Bizjets Rear-Engine/T-Tail?

Tue Apr 17, 2012 6:42 pm

Quoting RussianJet (Thread starter):
Is it principally a question of small wing needs to be a clean wing?

My major guess would be ground clearance. Not a whole lot of room under a bizjet wing to stow an engine.

Quoting RussianJet (Thread starter):
Are there any examples in existence?

Not a bizjet, but....


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Also found this thread:

Why No Wing-mounted Engines Small Jets (by Redcordes Feb 21 2007 in Tech Ops)
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Pihero
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RE: Why Are All Bizjets Rear-Engine/T-Tail?

Tue Apr 17, 2012 6:45 pm

Quoting KPWMSpotter (Reply 1):
Douglas made the configuration work,

Before Douglas, Sud Aviation pioneered the concept with the beautiful Caravelle.
Don't forget the 727, the Fokkers...etc...

The main problem of aft-mounted engines on an airliner is balance and as you said the ext-ra weight needed to reinforce the engine and the tailplane areas.
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citationjet
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RE: Why Are All Bizjets Rear-Engine/T-Tail?

Tue Apr 17, 2012 7:11 pm

Quoting RussianJet (Thread starter):
I think a tiny jet with engines slung under the wing would look cool, but is such a thing feasible?

Not all tiny biz jets have tiny engines. I don't think you would want to try and fit these big engines under the wings.

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KELPkid
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RE: Why Are All Bizjets Rear-Engine/T-Tail?

Tue Apr 17, 2012 7:28 pm

Well, I can think of one notable exception...


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RaginMav
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RE: Why Are All Bizjets Rear-Engine/T-Tail?

Tue Apr 17, 2012 7:39 pm

Quoting vikkyvik (Reply 3):
Not a bizjet, but....



Now we're onto something! A high-wing would allow for wing mounted engines, short landing gear, and would eliminate the annoying spar-carry-through protruding into the aircraft floor of some business aircraft.

The down fall may be headroom, as the spar would now be interfering with the ceiling structure.

Quoting KPWMSpotter (Reply 1):
Honda is now experimenting with the same thing with the Honda Jet. This keeps the airplane low, and the engine loads on the wing, but for some reason the configuration really hasn't caught on.



The canned answer is usually 'because they're ugly', although I don't entirely agree. For example, how different do these two competing deisngs really appear?


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RussianJet
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RE: Why Are All Bizjets Rear-Engine/T-Tail?

Tue Apr 17, 2012 7:43 pm

Great replies so far, thank you. Ground clearance is an obvious factor that I am kicking myself for not having considered, but then that is surely resolved with a higher wing, a la BAe-146 or indeed the Viking pictured in an earlier reply. Always thought the Viking looked great....but yes, not a bizjet of course.

Quoting CitationJet (Reply 5):
Not all tiny biz jets have tiny engines

Indeed not, but then - some do.

Quoting vikkyvik (Reply 3):
Why No Wing-mounted Engines Small Jets

Thank you for that, my friend.

The E170 is pretty small, with pretty small engines. Again, not a bizjet though of course.

How small can engines realistically get before they are just too inefficient? I can think of examples where small seems powerful, like an RR-powered A332.
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KELPkid
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RE: Why Are All Bizjets Rear-Engine/T-Tail?

Tue Apr 17, 2012 7:44 pm

Quoting CitationJet (Reply 5):
Not all tiny biz jets have tiny engines. I don't think you would want to try and fit these big engines under the wings.

The drag from the extra tall landing gear hanging down in the breeze would require higher power settings on approach. On the other hand, it would help your service ceiling certification requirements because it would probably get you down to altitude quicker on an emergency descent  Not to mention the need for built-in, retractable airstairs (a la early 737). But you'd have every lineman in the country mad at you, as refueling the Citation X would be more like refuelling a Merlin or Metro, a major pain in the arse.
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rwessel
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RE: Why Are All Bizjets Rear-Engine/T-Tail?

Tue Apr 17, 2012 9:17 pm

Quoting RussianJet (Reply 8):
Ground clearance is an obvious factor that I am kicking myself for not having considered, but then that is surely resolved with a higher wing,

Which leaves you a major problem of the wingbox passing through the occupied part of the cabin. Even the much larger (than a typical bizjet) BAe-146, has a quite noticeable protrusion into the cabin where the spars pass through. Then you either need to find room for the mains in the fuselage (since the really big Mach fairing is now going to be on top of the aircraft where you can't use it to hold stuff like wheels), or have really long gear legs.

Certainly not impossible to deal with, but a definite strike against the configuration.
 
RussianJet
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RE: Why Are All Bizjets Rear-Engine/T-Tail?

Tue Apr 17, 2012 9:25 pm

So basically we don't want a tiny plane on massive stilts, or a huge obstruction in the limited cabin space. Seems fairly sensible. On the other hand, 757-style big legs can look wicked.
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C46
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RE: Why Are All Bizjets Rear-Engine/T-Tail?

Tue Apr 17, 2012 9:48 pm

Wouldn't it also be quieter in the cabin with rear mounted engines which would be a good selling point for folks trying to be productive on a business trip?
 
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RE: Why Are All Bizjets Rear-Engine/T-Tail?

Tue Apr 17, 2012 10:17 pm

You can get short landing gear on a high-wing aircraft if you either retract them into drag-producing sponsons like the military airlifters, or into cutouts in your nice otherwise-round pressure vessel. It appears to me that the BAe-146 does a little of both.

I had a window seat under the wing of a BAe-146. The view of the #2 engine was terrific. I didn't see much ground, though, and no sky. I suppose that kind of view is a hard sell to the kind of people who use bizjets.
 
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RE: Why Are All Bizjets Rear-Engine/T-Tail?

Tue Apr 17, 2012 11:31 pm

Quoting RaginMav (Reply 7):
Now we're onto something! A high-wing would allow for wing mounted engines, short landing gear, and would eliminate the annoying spar-carry-through protruding into the aircraft floor of some business aircraft.

The down fall may be headroom, as the spar would now be interfering with the ceiling structure.

Yes but:

Quoting C46 (Reply 12):
Wouldn't it also be quieter in the cabin with rear mounted engines which would be a good selling point for folks trying to be productive on a business trip?

Noise is an issue with a high wing and underslung engines.
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BreninTW
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RE: Why Are All Bizjets Rear-Engine/T-Tail?

Wed Apr 18, 2012 1:23 am

Quoting Starlionblue (Reply 14):
Noise is an issue with a high wing and underslung engines.

I was recently on a BAe-146 for the first time (JNB - Maun) and, even though I am a fairly experienced flier, I nearly freaked when the flaps were retracted after takeoff. It sounded like the pilot had suddenly fire-walled the throttles and those engines were about to spin themselves off the wing. I was having pictures of experiencing my first-ever emergency landing, with my extremely nervous-flier mother sitting next to me.

It took me a few seconds to realize that the sound was the flap mechanism.

If I was in a biz jet, I would certainly not want that kind of noise each time I take off or land.
 
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RE: Why Are All Bizjets Rear-Engine/T-Tail?

Wed Apr 18, 2012 2:10 am

Quoting KPWMSpotter (Reply 1):
VFW-Fokker tried a "best of both worlds" approach with the engines on top of the wings on the VFW-614, Honda is now experimenting with the same thing with the Honda Jet. This keeps the airplane low, and the engine loads on the wing, but for some reason the configuration really hasn't caught on.

It's aerodynamically tricky; the upper surface of the wing is the most sensitive spot on the whole airplane. Trying to stick a strut there is not trivial.

Tom.
 
RussianJet
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RE: Why Are All Bizjets Rear-Engine/T-Tail?

Wed Apr 18, 2012 8:43 am

How about an 'engine in wing' design like the TU-104? now that *would* look amazing on a small jet.
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Fabo
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RE: Why Are All Bizjets Rear-Engine/T-Tail?

Wed Apr 18, 2012 9:54 am

Must be a maintenance nightmare. And I think aerodynamics are not that great either.
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RussianJet
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RE: Why Are All Bizjets Rear-Engine/T-Tail?

Wed Apr 18, 2012 9:56 am

Quoting Fabo (Reply 18):
And I think aerodynamics are not that great either

Worse than having struts on a small wing though? Maintenance yes, that's probably a given...
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RE: Why Are All Bizjets Rear-Engine/T-Tail?

Wed Apr 18, 2012 12:36 pm

Quoting CitationJet (Reply 5):

Most turbofans used on bizjets use engines that have centrifugal flow compressors making the engines shorter than the axial flow AE3007. The PW307 is similar in thrust rating to the AE3007 but much shorter as a result of the centrifugal compressor. The CJ610 and JT12 are also axial flow engines and longer as opposed to a TFE731 which is similar in thrust to the JT12.

Quoting C46 (Reply 12):
Wouldn't it also be quieter in the cabin with rear mounted engines which would be a good selling point for folks trying to be productive on a business trip?

Modern bizjets are fairly quit inside. Many of the designs have the baggage compartment between the engines. In the X you can hear and feel a hum from the engines at idle, but that's about it. Very little engine noise in flight.

Earlier bizjets like the Lears and Sabreliner are fairly loud inside.
 
RussianJet
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RE: Why Are All Bizjets Rear-Engine/T-Tail?

Wed Apr 18, 2012 12:44 pm

Quoting DashTrash (Reply 20):
Earlier bizjets like the Lears and Sabreliner are fairly loud inside.

Always imagined a Jetstar would be ridiculously loud inside, was it so?
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bj87
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RE: Why Are All Bizjets Rear-Engine/T-Tail?

Wed Apr 18, 2012 1:51 pm

Quoting RussianJet (Reply 17):
How about an 'engine in wing' design like the TU-104? now that *would* look amazing on a small jet.

I would love to see something like that! I think the DH Comet look would be even better but one would need a ridiculously thick wing to make that work on a bizjet so the TU-104 look will have to do.

Quoting Fabo (Reply 18):
Must be a maintenance nightmare. And I think aerodynamics are not that great either.

Safety might also become a factor. After all we are sticking a turbine between the fuel and the fuselage. One uncontained disc failure and you have one massive problem. That would probably mean additional reinforcements will be required on top of the reinforcement required to fit the engine in the wing in the first place. I am by no stretch of the imagination an aircraft expert but the weight penalty might be an issue.

Quoting brenintw (Reply 15):
I was recently on a BAe-146 for the first time (JNB - Maun) and, even though I am a fairly experienced flier, I nearly freaked when the flaps were retracted after takeoff.

You are not the only one with that problem. Let's just say the noise caught my attention on my one and only 146 flight. Btw the noise is such a special characteristic of the aircraft that the noise of flap motors is included in the professional flight simulators.
 
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RE: Why Are All Bizjets Rear-Engine/T-Tail?

Wed Apr 18, 2012 1:57 pm

Quoting bj87 (Reply 22):
but one would need a ridiculously thick wing to make that work on a bizjet

But would one? As I alluded to above, there are some good examples of seemingly small yet powerful engines, the reference for which was the RR-powered A332.
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Jetlagged
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RE: Why Are All Bizjets Rear-Engine/T-Tail?

Wed Apr 18, 2012 2:06 pm

In the Hondajet the engines are above and behind the wing, unlike the VFW 614. Thus they don't block the expensive view out of the cabin windows, produce less cabin noise and have much less interference with the wing uppersurface airflow. They are in roughly the same relative position as aft mounted engines on conventional biz-jets, but the mounting location is different, giving a structural advantage.

Quoting bj87 (Reply 22):
You are not the only one with that problem. Let's just say the noise caught my attention on my one and only 146 flight. Btw the noise is such a special characteristic of the aircraft that the noise of flap motors is included in the professional flight simulators.

I think it may well be an aerodynamic noise, as the TE slots close. It only happens during the last stage of flap retraction.
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RE: Why Are All Bizjets Rear-Engine/T-Tail?

Wed Apr 18, 2012 7:31 pm

Quoting RussianJet (Reply 21):
Always imagined a Jetstar would be ridiculously loud inside, was it so?

Don't know. Didn't fly the Jetstar.
 
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RE: Why Are All Bizjets Rear-Engine/T-Tail?

Wed Apr 18, 2012 8:26 pm

Quoting brenintw (Reply 15):
It took me a few seconds to realize that the sound was the flap mechanism.
Quoting Jetlagged (Reply 24):
Quoting bj87 (Reply 22):
You are not the only one with that problem. Let's just say the noise caught my attention on my one and only 146 flight. Btw the noise is such a special characteristic of the aircraft that the noise of flap motors is included in the professional flight simulators.

I think it may well be an aerodynamic noise, as the TE slots close. It only happens during the last stage of flap retraction.

I'm quite sure it's aerodynamic noise, not the flap mechanism. I've heard it dozens of times. Same noise on both flap retraction and extension.
 
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RE: Why Are All Bizjets Rear-Engine/T-Tail?

Thu Apr 19, 2012 12:09 am

Quoting RussianJet (Reply 21):
Always imagined a Jetstar would be ridiculously loud inside, was it so?


I think I will jump in here about the JetStar, to the contrary the airplane was fairly quiet in the cabin, the engines were way aft of the seating area, basically the forward half of the engine was next to the closet which was aft of the lav which itself was aft of the rear galley and the remaining aft part of the engine was next to the unpressurized aft compartment that JetStar operators commonly called the boiler room, which was accessed through a fuselage opening when the rear speed brake was extended and known as the hell hole.

The galley was placed directly above the main landing gear boxes on both sides of the cabin so the rearmost seats were far enough forward that engine noise was not that bad sitting in the rear seats, on takeoff you could hear the engines but during cruise not that much.

I spent enough time in the galley getting food ready for our passengers and you could have a normal conversation standing in the galley in flight. Also Lockheed did a very good job with using sound deadening insulation in all the nooks and crannies of the fuselage.

Unless we had more than 4 passengers, all the passengers sat in the forward 4 seats which were club style with the first 2 facing aft and the other 2 facing forward, in the back section of the cabin there was another set of 2 seats club style on the left side of the airplane looking forward and a 3 place divan along the right side of the cabin and it was no problem having a normal conversation there as well.

Most of the engine noise on the JT-12 was from the exhaust, not from the compressors unlike the Gulfstream 2, who you could hear the compressor noise on takeoff from a distance while standing on the ramp near the runways. Where I worked at HPN, our hangar was less than 1000 feet from the mid way point of runway 16-34 and during the summer months the hangar doors was always open and when a G2 took off, you could hear it way before you saw the airplane pass by the open doors.

Actually I remember the JetStar cabin was quieter than the airliners I fly on now today as a passenger.

JetStar
 
boacvc10
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RE: Why Are All Bizjets Rear-Engine/T-Tail?

Thu Apr 19, 2012 3:25 am

Quoting KELPkid (Reply 6):

Well, I can think of one notable exception...

A "roadster" by any other name. Can anyone comment on its performance / flight experience as measured? Why would four engines have been considered for such a small aircraft?
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soon7x7
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RE: Why Are All Bizjets Rear-Engine/T-Tail?

Thu Apr 19, 2012 3:55 am

The very nature of private jets is to be able to plane and deplane PAX wherever they operate without the need for jetways or drive up airstairs. The only way to achieve this little luxury is to keep the fuselage low enough so a one piece airstair exists. The Gulfstream has about the highest ground clearance but has a bisected airstair. Still precludes the requirement for ancillary airstair or jetway. The tail mounted engine configuration enables this function. Private jets, even some BBJ's and 757's that are Private have the integral airstair to operate on corporate ramps and other airports that do not have the luxury of jetways. The difference is the aircraft are so large...any configuration works. Mr. Trumps has the forward integral airstair in his 757. An unusual installation but when his aircraft belonged to Sterling Airways, three 757's were delivered with this configuration for operations up in Nordic airports. CRJ's were just variants of the corporate Challenger 600 series and while their PAX capacity is much greater than that of the 600 series, their desire to operate in smaller fields as regionals enables them not to require jetways. So the tail mounted configuration once again more effeicient.
 
KELPkid
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RE: Why Are All Bizjets Rear-Engine/T-Tail?

Thu Apr 19, 2012 8:53 pm

Quoting boacvc10 (Reply 28):
A "roadster" by any other name. Can anyone comment on its performance / flight experience as measured? Why would four engines have been considered for such a small aircraft?

Since it was designed to the same spec as the JetStar (a US Air Force request), I'm wondering if 4 engines was spelled out in the requrement? As we know, Lockheed won that one...

Also it could have something to do with the power output of the Westinghouse J34's...back then, a plane was engineered for engines, not the other way around  

Here's the (rather sparse) wiki article:

http://en.wikipedia.org/wiki/McDonnell_119
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jetstar
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RE: Why Are All Bizjets Rear-Engine/T-Tail?

Thu Apr 19, 2012 8:54 pm

Quoting boacvc10 (Reply 28):
A "roadster" by any other name. Can anyone comment on its performance / flight experience as measured? Why would four engines have been considered for such a small aircraft?

Both the JetStar and the McDonnell 220 were designed to compete for an US Air Force contract for a light VIP jet, While the McDonnell 220 was built right from scratch as a 4 engine airplane, the 2 JetStar prototypes were built with 2 engines.

I heard 2 stories as to whether the JetStar was designed as a 2 engine airplane or was it going to be a 4 engine airplane.

One story I heard from a JetStar flight instructor when I was going through the JetStar maintenance course in 1973 at the factory in Marietta GA was that the JetStar was going to be a 2 engine airplane but the JetStar could not meet the US Air Force for second stage climb requirements because of the amount of thrust from the 2 engines so Lockheed had to go with 4 engines to remain in the contract competition.

The other story I heard was from the head JetStar salesman who told me that the airplane was designed to use 4 engines, but because the P&W JT-12 was not yet certified and to get a head start on flight testing the airframe and systems, Kelly Johnson, who designed the JetStar used 2 British Orpheus engines to power the airplane. McDonnell had already hooked up with Westinghouse on the J-47 engine, so these engines was not available to Lockheed and there were no other small engines available for Lockheed to use, so Lockheed was stuck with using the Orpheus for the 2 prototypes.

I personally believe the Lockheed salesman story because one of the missions for the light jet requirement was for presidential use. The was a rule back then that the president only flies on 4 engine airplanes and something smaller than the presidential 707’s was needed when he needed to travel to smaller airports or on personal travel, like when JFK would fly to his summer home on Cape Cod.

The first prototype, serial number 1001 stayed with the 2 engines and was used for many years as Kelly Johnson’s personal company airplane while the second prototype, 1002 was converted to the 4 engine configuration and was used as the flying testbed.

Both these prototypes still exist today, 1001 is in the Museum of Flight’s restoration center is Everett WA, I saw it there 2 years ago and they told me they hope one day to restore it to flight condition. 1002 is on display at Andrews Air Force Base painted up to represent one of the 16 JetStar’s the Air Force bought.

As you can tell by my user name, my love for this airplane, I had the great fortune to both work and fly the JetStar and even though it has been over 30 years since I last sat in the pilots seat or twisted a wrench on a JetStar, it will always be my favorite airplane, after my 1964 Cessna 150 which I have owned since 1968.

Thanks for allowing me to share some memories of the Lockheed JetStar.

JetStar
 
MD-90
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RE: Why Are All Bizjets Rear-Engine/T-Tail?

Fri Apr 20, 2012 6:37 am

As far as bizjets are concerned don't forget that it's easier to manufacture a fuselage sitting on top of a wing (especially if one is carbon fiber and the other aluminum) and connect it with bolts. That allows the fuselage to handle the pressurization loads and the wing body fairing to be unpressurized. It's cheaper to build and maintain--and a great example of this is indeed the Citation X. This is why older bizjets have the wing entering the floor of the cabin while newer bizjets seem to be built "on top" of the wing.
 
jetstar
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RE: Why Are All Bizjets Rear-Engine/T-Tail?

Sun Apr 22, 2012 4:16 pm

Quoting MD-90 (Reply 32):
As far as bizjets are concerned don't forget that it's easier to manufacture a fuselage sitting on top of a wing (especially if one is carbon fiber and the other aluminum) and connect it with bolts. That allows the fuselage to handle the pressurization loads and the wing body fairing to be unpressurized. It's cheaper to build and maintain--and a great example of this is indeed the Citation X. This is why older bizjets have the wing entering the floor of the cabin while newer bizjets seem to be built "on top" of the wing.


Both the Lockheed JetStar and the Gulfstream 2, both very early biz jets have the fuselage mounted above the wings.

On the JetStar the fuselage sits on top of a cradle like frame assembly and the wings are attached to the sides of the frame. There was an early AD note out of the JetStar’s because the frames where the wings are mounted to were cracking, and the AD note required the uncracked frames to be shot peened to relieve the stresses on the frames and the cracked frames to be replaced.

To change a main fuel tank boost pump, once the belly panels were unscrewed and removed, you had access to the entire vertical portion of the inboard part of the wing, and both main fuel boost pumps, one for each fuel tank, there are 2 internal fuel tanks in each wing were accessible. Gaining access to the pumps was the easy part, changing them was a bitch, but that’s another story in itself.

I did notice when I saw the prototype JetStar at the Museum of Flight’s restoration center that the wings were mounted directly to the fuselage, so this was a major change from the prototype to the production airplanes.

On the Gulfstream G2 and up series airplanes, the wings are attached to each other and are basically one structure and the fuselage sits on top of the wing, there is no center wing box section like on the airliners. When Gulfstream did a major optional upgrade to the G2 by using the wings of the G3, basically all that it required was to lift the fuselage off the wings, roll the old wings out from underneath the airplane and roll in the new wings. I know it was more than just that, requiring changing over the landing gear and other accessories, but as far as I know, no major structural work was required on the fuselage.

JetStar
 
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tjwgrr
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RE: Why Are All Bizjets Rear-Engine/T-Tail?

Fri Apr 27, 2012 1:13 pm

No rear mounted engines here:


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Granted, the Dork Jet wasn't really designed to be a biz-jet.

..
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KELPkid
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RE: Why Are All Bizjets Rear-Engine/T-Tail?

Fri Apr 27, 2012 8:24 pm

Quoting tjwgrr (Reply 34):

Granted, the Dork Jet wasn't really designed to be a biz-jet.

Nor was it designed to be a jet   It is a turboprop airframe w/2 pure jets slapped on it.
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Western727
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RE: Why Are All Bizjets Rear-Engine/T-Tail?

Fri Apr 27, 2012 8:58 pm

Fascinating thread. May I add (speculation only): a desire to keep the aircraft height as low as possible to fit in smaller hangars. After all, wing-mounted engines result in:

1. A higher fuselage (and gear, as has been said)
2. A larger vert stab due to the greater distance of the engines from the centerline, thus greater asymmetrical-thrust forces to contend with

...thus, both would cause the overall height of the jet to jump quite a bit. Hard to find bizjet FBOs with tall-enough hangars for such a scenario, I imagine.
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Starlionblue
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RE: Why Are All Bizjets Rear-Engine/T-Tail?

Sat Apr 28, 2012 5:22 am

Quoting tjwgrr (Reply 34):
Granted, the Dork Jet wasn't really designed to be a biz-jet.

Or a jet. 
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MD-90
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RE: Why Are All Bizjets Rear-Engine/T-Tail?

Mon Apr 30, 2012 8:18 am

Quoting tjwgrr (Reply 34):
Granted, the Dork Jet wasn't really designed to be a biz-jet.

I always thought it was a cute plane, though.
 
Fabo
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RE: Why Are All Bizjets Rear-Engine/T-Tail?

Mon Apr 30, 2012 1:33 pm

I was supposed to work one. Then a sup switched me over to a 735 we had some seating or checkin system problems with. Dreaded day...
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rampart
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RE: Why Are All Bizjets Rear-Engine/T-Tail?

Wed May 02, 2012 11:21 am

Quoting RussianJet (Thread starter):
Seems to me that basically all small-medium bizjets are rear-engined with either a t-tail, or in Dassault's case a sort of 'cross' tail (which, btw, I think looks beautiful).

I'm thinking the majority of these bizjets have t-tails, a smaller proportion have the cruciform tail (you mention the Falcon, also the Jetstar, Corvette, Westwind and Astra, Citation I-V (where the newer revisions have become T-tails). I can only think of the Sabreliner as having a conventional tail.

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Chese
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RE: Why Are All Bizjets Rear-Engine/T-Tail?

Fri May 04, 2012 4:24 am

The cruciform tail is still fairly popular. Hawkers, Falcons, still many Citations. I like it in that there it makes working on the stab much easier as it is lower. Getting on top of a Citation X tail to change a light is not my favorite thing. The simple reason I see for the common design of tail mounted engines is simply clearance. Low mounted wing and wing mounted engines would be too tall for most sizes of bizjets that have built in air stairs.
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