Leeham News and Analysis
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Leeham News and Analysis
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- Bjorn’s Corner: New engine development. Part 3. Propulsive efficiency April 12, 2024
- A350-1000 or 777-9? Part 2 April 11, 2024
- Pontifications: Boeing “transparency”–not so much. April 9, 2024
- Airbus charges and write-offs since 1999: more than €33bn April 8, 2024
Bjorn’s Corner: MRJ90 first flight
By Bjorn Fehrm
13 November 2015, ©. Leeham Co: Mitsubishi flew their MRJ for the first time this week. I could have added “finally” because it is two years late compared to the original time plan. But who cares when the aircraft is finally ready to fly and everything goes well? (Well, the customers do, actually.)
It was a big moment for Japan, a nation with a sizable aeronautical industry. Japan has been a major partner to Boeing in their larger airplane programs over the 757/767 to the 777 and 787. For the Dreamliner, they even designed and made the hottest item, the high-tech Carbon Fibre Reinforced Plastic (CFRP) wing.
Despite having such a capable aeronautical industry, Japan has not built an own civil aircraft since it closed the production line for the YS-11 twin engined turboprop in 1973. Since then it has acted as sub-supplier and has worked on certain military programs like the Mitsubishi F-2 fighter, based on the Lockheed Martin F16.
The Mitsubishi corporation flew the MRJ90 for the first time Wednesday from the Nagoya Airport in Japan (screenshot from video from Mitsubishi). Most of the flight testing will be done in Moses Lake (WA), USA, where four test airplanes will be based.
Moses Lake is blessed with open skies, little air traffic, a long runway and good weather. It has a long history of flight testing, serving as a test-base for Japan Air Lines 747 pilot training for decades. Boeing also uses Moses Lake for flight testing.
We analyzed the MRJ90 and its main competitor the Embraer E175 in a subscriber article the 25th of January. We will revisit the main characteristics and then comment on what could be seen from the first flight.
MRJ90
The MRJ is a regional jet in the 70 to 100 seat segment. It has been designed with a slender fuselage, Figure 1. By careful design on its circular fuselage, it has managed to have the same internal dimension as the larger Embraer E-Jet which uses a double bubble fuselage cross-section.
Bombardier and Embraer have managed to get the typical roller bag going in wheels-first in the CSeries and E-Jet E2. MRJ and the original E-Jet stow them on the side.
Figure 1. Cross sections of the Bombardier, Embraer and Mitsubishi regional jets. Source: Leeham Co.
As can be seen from Figure 2, the cabins between the MRJ90 and E175-E2 are virtually identical despite the E-jet being considerably shorter. This comes from Mitsubishi having decided to put the passenger luggage in the tail cone and use the small under-floor cavity for avionics and systems. They claim they thereby avoid the somewhat cramped (for the loaders) luggage compartment of the E-Jet, thus speeding luggage loading/unloading.
Figure 2. Side views of MRJ90 and E175 E2 with cabins. Source: Leeham Co. Click for better view.
The data for the aircraft are very similar (the MRJ90 data is for the LR version, there are also less capable STD and ER versions), Figure 3. The E-jet has a wider wing, giving it a very high aspect ratio. Both wings are of classical aluminium construction. Wetted areas are similar despite quite different planforms, Figure 4.
Figure 3. MRJ90 and E175-E2 main data. Source: Leeham Co.
In our analysis of January, we found them to be close in fuel efficiency. This is to be expected as they are similar in weights and wetted areas. The E-jet E2 has an advantage on longer legs as it has a wing with a higher effective aspect ratio.
Figure 4. Planform of MRJ90 and E175-E2. Source: Leeham Co.
First flight
The first flight went well, according to Mitsubishi; it said the aircraft’s behaviour exceeded its expectations. Such expression are standard today irrespective what happened on the flight, so one shall not put too much weight on such comments.
Looking at the video from the first flight, a few things are noteworthy, however. The aircraft rotates with a low deflection of the stabilator. It then continues the climb with the horizontal tail plane at a low trim position and once again moderate stabilator deflections. The landing shows the same behaviour.
It is of course too early to give any verdict on how the aircraft will function based on external observations from a first flight, but the low input needed to change the pitch attitude caught my attention. The aircraft uses Fly-By-Wire and it might allow low static stability margins (which leads to low stabilator deflections and HTP trim angles and eventually low trim drag).
Anyway, an un-dramatic first flight with an aircraft that seemed to fly well.
Why is it, that the did the whole flight with gears down? Were they not confident enough that this works?
It has more to do with how the flight test planners want things done, I think. Japanese mentality is extremely methodical and they might just want to take one step at a time. It is quite common to fly the first sortie without cycling the gear.
Seems like a good aircraft. Slightly lower capacity than E2, in general, because of the luggage option that was selected. Maybe slightly lighter / lower drag too? Same engine as E2.. The existing global support base for the E2 helps, so MHI will have to buy itself in to get things going.
Apart from the F2/F16 the Japanese industry build MPA’s, Transports, Flyingboats, Attack helicopters in recent decades and have strong capable research entities. Engines, Space, Avionics, they all develop & build it.
Reality is the Japanese – Chinese still have cool relations based on deep historical wounds. Otherwise Japanese aerospace knowhow with Comac finance and production power would create a different game for A & B.
Björn, I’m a bit shaky on regional aircraft design. Why do both a/c sport a relativly low wing loading? I would have guessed it’s due to planned stretch versions. However to my knowledge the E2-175 has a wing for its own; the E2-190 and -195 have a larger wing. So what’s the reason then? Are they fuel-limited?
I think it is more they are supposed to operate from secondary airports and need shorter take-off and landing distances. Wingloading is determining your lift-off and landing speed everything else being equal. They also fly predominately short distance with an average of around 500nm sectors or less. The OEMs therefore push the wing design more direction field performance than for longer range aircraft. This means a larger wing to carry a certain max weight (MTOW) = low wingloading.
Anyone know if the MRJ90 can operate off 5000 foot runways or is it going to need more as do the ERJ-145’s and CRJ-200’s?
I was hoping this could open up more routes that up until now only turbo props at small airports offered the only hope of airline service.
The 39.6t std version should, remains to be seen if it gets sold.
Circa 1980 a large wing gave higher altitude capability as well, which had advantages in crowded airspace (whereas DC-10s struggled).
I don’t recall how that affected fuel efficiency, my experience was mostly with the 767 which was over-winged for growth.
Of course the ultimate in big wing giving altitude was the 747SP in competition with the DC10-30.
(Including trans-oceanic with three engines, never built as two-engines in oceanic/remote became accepted, of course max weights went way up and the fuselage was stretched so the big wing was used to effect.)
IIRC optimum flight profile for the 767-200 on the Calgary-Edmonton shuttle, 150nm, was to climb until top-of-descent. (Pacific Western planned to use it on that run, into the short runway at YXD, but the large hunk of metal would reduce airport capacity when anywhere near the end of the runway due effect on ILS, that was a busy airport for small and business aircraft. PW’s frequency with 737s was every half hour in peak periods which wasn’t enough, so a bigger aircraft was an attractive option.)
From the cabin cross sections and the side views its apparent that the MRJ has a rear main deck baggage hold. Would this be a factor in the capabilities of the rear stabilator as the FBW would have to allow for a concentrated rear weight with a long moment arm at rotation and after. Of course it would be unlikely for first flight to have baggage in rear location but it might contain flight instrumentation equipment.
The center of gravity of an aircraft is very carefully designed to be within a certain range dependent on how the aircraft is loaded. Irrespective of where the luggage is placed Mitsubishi and later the airlines will have to make sure the aircraft is loaded according to these design margins. One measures the CG location in how many percent of the wings mean cord it is placed from the leading edge of the wing. A typical allowed range is 15% to 45% of the mean cord.
For a first test flight you place the aircraft’s CG at the mid point of such a range, it is part of flight test to gradually open up the forward and aft CG range. At the most rear heavy CG location the aircraft closes in on being unstable, ie it has pitch oscillation tendencies if one crosses the aft limit. At the most forward CG location it is very stable but requires a lot of stabilator deflection to change pitch angle. So given that the aircraft for sure was taking off with a mid CG location the ease of rotation was noticeable.
What is the empty operating weight of the MRJ and the E175E2?
Are you sure the Japanese “designed” the wings on the 787? I would suggest they were designed in house by Boeing.
going by the interface mismatch we saw between wing and wingbox/fuselage join my guess would be that Boeing handed out rather vague design specs to be filled out by the subcontractor.
Some kind of napkin drawing ?
Maybe it was designed by Airbus? Never mind, no cracks in it! 🙂
I appreciated your humour A J K
Boeing wasnt so interested in deep design details, but they spent a lot of time on this
““One of the things the committee came up with was the idea of ‘airplanes for people.’ What that meant was that everyone who came into contact with the airplane—crew, mechanics, or flying passengers—was going to say ‘Wow. Boeing has really thought of me when they built this airplane.’
Between focus groups and Rapaille’s advice, Boeing discovered not only how people view flight, but also what sorts of features in an airliner’s interior might have universal appeal. Those include…well, Emery won’t say. “We learned a lot of cool stuff,” he says, with a faint, satisfied smile.
http://www.airspacemag.com/flight-today/how-boeing-put-the-dream-in-dreamliner-20968765/?no-ist
Of course that was all back in 2007 and they were looking deep into the ‘reptile brain’ of people to see what their deepest needs were, while the other stuff like detail design and manufacture would look after itself.
Fluff.
Mostly they were delving into their carpet bags for more PR gimmicks to feed the junkies already salivating over the four-color-glossies.
Boeing did the overall design as they did with all parts ie aerodynamic form, overall loads and requirements. The Japanese partners then did the detail design and importantly did the manufacturing design, ie how to manufacture such an advanced piece. This meant a very important part of the know-how around such a wing ended up outside Boeing and Boeing’s CEO who was brought in to sort out the 787 mess, Jim Albaugh, later said no longer shall such key parts be outsourced for future aircraft projects.
“This meant a very important part of the know-how around such a wing ended up outside Boeing and Jim Albaugh later said not longer shall such key parts be outsourced for future projects.”
So this task is still open for the 777x’s wing ?
The 777X wing is designed 100% inside Boeing (which included overall design of aero, loads,deflections, … then detail design and finally manufacturing concept and design) and for the very reason that it was stupid and dangerous to learn capable nations like Japan how to do such things. Boeing’s board at the time had the idea that Boeing could focus on being the system integrator and didn’t have to bother with the tedious and expensive exersice of designing aircraft parts. This is normally the step before you get relegated to an also ran in the market, luckily saner people realized what was about to happen.
Thanks Bjorn.
They still need to verify that their design work is adequate and then gain the experience in the details of CFRP wing manufacture., right?
i.e. they again will have to swim in unknown waters.
I don’t think so. Boeing has a lost of CFRP manufacturing experience after doing a big portion of the B2, now a portion of 787 after buying Vought’s 787 manufacturing, the tail of 777 etc. The problem was the idea of outsourcing vital technology for others to learn to reduce their own development spend and increase ROAE when they had all the financial muscles to do it themselves. This is now fixed, Boeing has a clear strategy what to do and what to outsource.
I appreciated your humour.
Boeing 787 wing was design in total in house. Tested in 3 locations in the wind tunnel in the USA and in the U.K. The manufacturing blue prints and mandrel a was giving to the Japanese. The hatred of BA by some of the E.U . Airbus fans cloud their judgement. BA has vow to out deliver planes for the next 10 years internally no matter how many plane Airbus sell.
I think many that assumed Boeing outdelivering Airbus for the next 5 years, assumed stable 777 deliveries, a 50-50 on narrowbodies and the A330 being phased out.
Your narrative just does not match the historic run of things all that well.
There is no hatred. If anything than it is exasperation.