ATR92
 

I've heard of ATR mulling over a clean sheet..but haven't seen any concepts. I'd love to know more.

Being a KIWI flier, I'd bet you do some pretty steep aproaches (being mostly mountain out there)...and on that I know the Q's are better than the ATR. I wonder if the ATR92 will address that defficiency. That would allow a nice big turboprop to service the city centre airport here in Toronto and improve service to some of the busier destinations.

Any links to where I can see what they have on the shopping list?

ATR and Hotel Mode
 

Even ATR is beginning to admit that Hotel Mode isn't very good. They've implemented in their -600 variant an electrothermal air conditioning unit to "supplement" hotel mode bleed powered cabin cooling. (Talk about adding weight!) You've gotta love how they spin this correction for lack of original performance as a wonderful enhancement LOL:E (Engineer's rule #2: If you can't fix it, call it a feature)

The APU on the Q series is much better than hotel mode, and DOES operate unattended. (unlike some APUs and Hotel mode).
ATR also put the hotel mode on the same side as the service entrance and fuel fill port. so no servicing can be done. So much for turnaround time at the gate. :ugh:
Sure, they cal Hotel time "ZERO ENGINE" time ...but the prop brake fails pretty often. (under 3000 hrs mtbf). I am pretty sure APUs last longer than THAT!

ATR & Hotel Mode
 

I agree that the APU maybe the more cooler method but part of that reason is that it can be left going for the whole turn around, hence has a longer period to try and cool the aircraft. In hotel, it needs to be shut down for servicing, fuel and unloading the rear of the aircraft. It is generally started only 5 sometimes 10minutes before departure so with a full load on a hot day it is already way behind trying to cool down a 30+C cabin. The complaints we get from the cabincrew the most is with a full cabin the air con struggles to keep it cool.

ATR92
I know a little about this only in the form that with our fleet soon to be up for renewal ATR have been briefing our managers on the replacement for the atr 500/600 which i think is to be designated the 700 (high70seats) and the atr92 (90+ seats). Both clean sheet designs.
Same general layout as the current atr but with a major change being that the baggage/cargo holds will be placed underfloor. Still the gear in pods from the fuselage. Passenger entry will be via a front door. Not sure if it is going with a prop brake or not?
The target design speed is a cruise TAS of 320-330, so I guess an indication that atr conceed a little more speed would be better.
Will incorporate all new A350/380 technoligies. Will have a new technology anti/de-ice system which won't require bleed air. Hydralulics will be individual power packs at each point which requires them. No central system.
I am pretty sure that it is going to be side stick, so fly by wire also.
Will try and find more out but there is nothing on the net yet as is all still concept and planning at ATR.

Cheers

Keesje,
 

Good work !
Still two remarks :
1/- Have you thought of the *gull wing* solution for a low wing project ?
Seems to work on a 380... and will improve the design (aerodynamics ) wing-to-fuselage connection ( perpendicular attachment )while shortening the landing gear legs.
2/- I notice that your props turn the same way...with 11,000 hp behind them, you have a massive torque effect while manoeuvering (right turn on a pitch-up, left on a pitch-down)...That will lead to piloting difficulties -and certification requirements on a *critical engine* (pitch-down moment on a right engine failure) or a serious study of autopilot controlled engine failure.
IMHO, you'll have two solutions :
2-a/- Contra-rotating props (that will also improve your trans-sonic aerodynamics on the prop tips)
2-b/- opposite rotation directions on the props...which means an increased investment on spare parts...not my favourite idea.

Your choice.

Regards

ATR92
 

Sounds exciting.
I read in ATI that they were looking at a mid 80s size, but not the 70s...I hope it isn't a deplug of the 90 version. Deplugs are heavy and not really worth it. (look at the A318 vs the A320).

Cool that ATR caught on to a single baggage bay, I thought the 3 different points was a pain..and the largest compartment being in a shared area with pax boarding and galley service was stupid. And speed looks good, but is it enough?? Donno. We regularly push the Q4s right to the 360s...it is incredible when we get to Ottawa, some AC Airbus drivers complain how we leave them in the dust...beating them to YOW by 5 mins easy! ATR should go big...

That's what I kinda like about this Turboliner..big, fast. (Hey, maybe this is ATRs way of gauging public reaction to the next ATR, we could be influencing history here!)

Thnx for the responses. I was on a trip this week. In the week-end I will find time for a better look & maybe do a mark IV based on your comments.

• Question 1: I included DLC to improve approach handling. Now it's spoilers + DLC spoilers, which seems overdone. Maybe they could be combined, any suggestions? Could save some weight / complexity.
• Question 2: I included "active cooled power brakes" because thrust reverse works very well for props but makes a lot of noise too. No thrust reverse after landing & electric drive to the gate would really make a difference in total noise pollution. Is there a smart way to use the electric engines as generators during roll out & use the energy to cool the brakes? Or would it be simpler to put on the APU before landing to provide power to a blower/compressor?
• On the low wings+ big props: I took a look & will post some configs I looked at. Think about the recent LH A320 wingtip incident.. http://www.youtube.com/watch?v=z42fchrzhHY Ground clearance would be a design concern.
• On speed : Mach 0.7 is a lot of speed at 25k ft, the Turboliner should be able to do 440 knots like the bulkier A400M (max cruise M.72).
• On prop tip fuselage clearance : I looked at A400M prop-fuselage clearance and added ~20%. Powerplants to far from the cg creates asymetric / 1 engine out issues (bigger tail, weight /drag)
• Counter rotating props are being looked at by the OEMS indeed. They offer advantages (reduced rotor diameter) but also have some issues of there own I think: heavy gearboxes and noise (interference between props) e.g. I guess I sticked on the safe side with an existing engine / prop combination.
• Opposite rotation seems possible (A400M has it too). Less trimming means less drag. It had so in post 1..

rgds

Hello

I summarized everything in 1 slide. Changes:

• counter rotating props
• combined DLC / liftdumpers

http://i191.photobucket.com/albums/z...g?t=1208899184

rgds

Delightful to see the original and lateral thinking. Kees, congratulations for pushing it beyond the first negative responses of the “it’ll never work” variety.

Maybe it won’t. But the thinking behind it – and the general response on Pprune – is surely being quietly observed by many an aeronautical enginner and market analyst in Boeing, Airbus and a few others.

Kiwilad in post 34 pointed out that most people don’t know/aren’t given a choice as to the aircraft type they’ll be traveling on. I agree, and I think an increasing proportion of travelers are more concerned with the combination of price/comfort/direct flight, not necessarily in that order. The relative speed advantage of a jet over a turboprop over 1-1.5 hour sectors, when considered in the context of all the time getting to an airport, checking in and waiting, just seems risible. And if you can get a TP aircraft closer to the passenger than would be possible with a jet, hurrah. Operators,as we’ve seen in the USA in the last few weeks, are more than a little concerned with the cost of fuel, however much they might have hedged.

In my industry, the rising fuel cost component is already nudging shipowners to reduce speed and maintain their weekly port call schedules by inserting another vessel in the cycle. It could be the seventh, the ninth or the eleventh ship but the savings are in the high millions. Sounds easy enough in liner shipping, yes, where there is an icreasing capacity glut; I know it’s more difficult in aviation where the parameters of fuel efficiency are much more restrictive. Just perhaps, you’ve come up with the right idea at the right time.

:ok: All you need now is a better name than "TurboLiner" and that reflects all the thoughtful Pprune input. That might perhaps better be left to JetBlast.

In the name of pax safety, place the seats facing rearwards. Make row 1 at the rear of the aircraft. If pax board via two doors, they will hardly notice the difference. Tilt the fixed seat-back angle at about 20 degrees and Take off angles will not be a problem. It might well be that seat fixings and rails can be of lighter construction and still maintain crash G criteria.
Place the windows slightly lower in the fuselage to give the aisle seat pax a view outside. Who wants to look sideways anyway?

As I understand it, rear facing seats do have the advantage of being safer than forward facing seats for the pax in the event of an incident. Given proper structural design of course.

I believe the issue with them, or all airliners would have them already, is that the loads are placed higher into the back of the seat, therefore requiring a stiffer structure to resist the forces in the event of a sudden deceleration. {Forward facing seats put the loads into the seat at seatbelt level.} Which therefore requires a stronger floor, therefore a bit more weight, therefore increased cost of fuel per flight, therefore increasing the operational costs of the aircraft ...

I'm not sure how much of an impact this would have in terms of a relatively short haul aircraft like the Turboliner, but it would be a consideration. Economics vs. innovation as always.

Keesje - interesting design. Hopefully I'll get a chance to fly in it or something like it someday. :ok:

Thnx for your kind words. As you mention challenges in shipping, automotive and aerospace aren't that different if you look at them from a distance. All are balanced trade-offs that move when the environment changes. Old, shelved ideas become feasible again.. Everybody check their archives :ok:!

Be my guest :), the combined creativity of PPrune should be able to come up with something better!

rubik101. Interesting idea:cool:. I think the Aerospace community concluded rearward facing seats are a good idea decades ago. It's up to the airlines, as you say little technical complications. Still no one uses them. I'm thinking about doing the rows in front of the emergency exit rearward, leaving a choice to the passengers. Maybe statisticly the seats after and in front of the wing would offer similar safety (an aircraft seldom crashes on its tail..)

Yes, the size / location of the windows always is a compromise. Weight, light, the bright sun beam above the clouds, the view from the middle / aisle seats.. Big windows seem fashionable now, composites allow for it I guess.

http://www.luxurylaunches.com/entry_...dows-thumb.jpg
787

IMO the rooftop windows could improve the experience in the cabin, specailly for aisle passengers. It a dense cabin, being able to see the blue sky / sunlight entering the cabin could improve the general admosphere.

Talking about the windows, nobody questioned the higher windows next to the doors. They have a double function : allowing the crew to easily see what's outside before opening the doors & provide natural light in the galleys / lavatory areas. For an aircraft doing up to 8 flights a day this could prevent docking damage / enhance working conditions during intense crew / catering work.

I thought the above version would be the final one, but I guess another one. Any additional modifications / insights /ideas? :confused:

rgds

Don't go low
 

Skip the thought on low windows... I'm over 6 feet tall and have to slouch to see anything. Sure, bring the lower part of the sill down, but the topp sill should be created to maximise viewing angle for someone of my height (it IS all about me). Mind you, where I usually sit on a plane, I have the best veiw of all!

I think Broadreach hit it on the head...there's got to be a trawler or 2 here from OEMs...what do you plan on doing with yout idea when you're done? Sell it? Just hope an oem picks it up for bragging rights?

Hell, DO you work for an OEM and you're getting a feeling for what we pilots want? That's cool by me too! You don't have to say who ya work for, I'd just be damn glad someone asked a pilot's opinion before they build the thing!:D

Hello, Keesje.
Quote :"...thrust reverse works very well for props but makes a lot of noise too. No thrust reverse after landing & electric drive to the gate would really make a difference in total noise pollution. Is there a smart way to use the electric engines as generators during roll out & use the energy to cool the brakes? Or would it be simpler to put on the APU before landing to provide power to a blower/compressor?
"
1/- You can do away with reversers altogether, the props give enough drag in the Betra range ( you'll need to keep that one, if only for line-up ! ) and a 1500 m runway should be ample for your performance.
2/- I do not think that the brake cooling is that much of an issue : your landing speeds would be a lot lower than on an equivalent jet and it's not as though the brake temps would shoot-up immediately.
3/- Why not go a bit further and have an APU auto-start + auto switching to the APU generator after landing. As you'll need some cooling / temp stabilisation time before you cut the engines off, the transition from traction to wheel drive would be very smooth.

Now a few issues with the flight controls : at the speeds you're considering, a trimmable horizontal tail is the best choice --> The to-day position needs to be re-designed again.
The high-lift devices solution are still not very clear...and the roll control ? high speed aileron, spoilers, low speed ailerons/flapperons ?

wheel motors and "dead engine" taxying
 

The principle of regenerative braking is already very well established in the automotive and railway worlds...so your wheel-motors would ,presumably be fixed stators with rotating discs (hall-effect)...the disc could also be used as a brake-disc.

regarding the main engines, I understood they needed to run a while for temperatures to stabilise. Unlike a car, you couldn't just drive your overgrown electric golf-buggy to the end of the runway, switch from "drive" to "ignition ", light the fires and "balls to the wall"

so, you'd still need the engines startedwell in advance of takeoff.
would the fuel-burn be considerably less than running the APU?
what would be the feasibility of a big generator built-into the main engine(s) to power the gear-propulsion ? this could "drop-out" at a pre-determined engine RPM, saving mechanical drag.

(or is the on-board battery-system envisaged to store sufficient power for ground-manoeuvers?

Sorry if I'm talking crap! I'm not "in the trade"

Hi FireLight, mcgnuggitt, Lemurian, cockney steve, thnx for your comments. I'll take a close look in the week-end.

Ecoflyer, ppropliner, cityhopper, ppropexpress, ropconnect, whisperliner, electroflyer , cityexpress, ecoexpress, ecopprop.. :\ any inspiration?

Just let it flow maybe trigger someone to find the right name..

I would make sure it is possible to close the window blinds on the roof windows while standing in the aisle , blazing midday sun on your face when you trying to doze could result in air rage!

Innovative ideas
 

We have got to come up with some new ideas or we will not have an industry to work in.
Have you thought of talking to the Royal Aeronautical Society - you might get some worthwhile feedback from some of the people there.

"New Truths are first ridiculed, then violently opposed, and then accepted."

Rubik101, as firelight said, seats would become heavier. Current seats are designed for 16g forward. Backward facing people could survive (much) more. However the rest of the aircraft structure not. So I guess at 30g you and the seat could maybe survive but the rest of the aircraft would crunch. Thinking about it, I can not remember a 16 g kind of crash. It always seems less or so much more nothing helps..

Lemurian, I have the feeling thrust reverse should remain an option. The props have the mechanism anyways. On slippery runways, tail wind etc. they could be a usefull fall back option. Your second suggestion is very valid I realize. If this is to be a 737/A320 replacement dedicated for short high frequency flight, as I stated in the opening post, very short airfield performance is not a basic requirement. It could be an optional package. I left the power brakes out of the later concepts.

Cockney Steve, Lemurain, I guess the engines should be started on a specified time and place. I guess it would depend on the airport layout / time/ distance to the runway. LCY and AMS northern "polderbaan" are two extremes. I think a system that can be (de)activated by the crew and performs all actions in sequence monitoring engine parameters, outside conditions etc. would be a doable / practicle solution.

The horizontal tail has the similar configuration as the ARJ family. Maybe something better is possible. I made a conservative choice. The highlift devices are a single slotted flap and a flaperon similar to e.g. the 777. http://youtube.com/watch?v=jOG4A1_99mo (I included it in the picture)

The Wheeltug guys claim a lot of fuel can be saved, easiliy compensating the weight of the electromechanical components. I think batteries to supply the amounts of energy required would get very heavy. Batteries get better and better, but very slowly..

Capster, you are right I foresee the window would be semi transparent, spreading the light into the cabin. Passengers can see the sky is blue but not much more. Of course crew should be able to dim it or shut it like other cabin windows.

http://i191.photobucket.com/albums/z...g?t=1209337856

Masai, thnx, haven't communicated outside pprune.

Keesje, Fantastic concept my friend. I can appriciate what your trying to do, blend the advantages of jets and TP's.

The 6 abreast seating is a great idea for a start. I fly the 146, and as far as I can tell, most pax prefer a roomy, quiet cabin, rather than the engine type (jet or prop) It's irrelevant if you can keep the noise down inside your cabin, noise and vibration are the key factors in pax comfort.

Regarding your idea of taxiing out with your engines shut down, using the electric drives, I'm certain at LCY (where I fly the 146 into :} ) this wouldn't be advantageous. Holding times at WORST in my experience are 10-15 mins. And backtracking down the runway requires a higher than normal taxi speed. I'm not sure your electric drives could produce up to 30knots in taxi speed. And to be honest, using TP engines, your fuel efficiency is higher than a regional jet anyway, so I would guess that any fuel saving from taxiing with your engines shutdown will be negligible.

Another thing about starting your engines at the runway (or near it) that concerns me is electrical power. Considering your APU will be running your electrical drives, as well as the entire AC system of your aircraft, The chance for failure of the APU generator is higher. Imagine if your APU/APU generator failed on taxi out. Your aircraft would come to a halt in the middle of the taxiway. With no AC electrical power. PA system wouldn't work so communications with cabin crew and pax would be difficult, and if at night, cabin plunged into darkness with only emergency lighting. Not good.

Also the late starting of engines poses problems (again)

Say one of your engines won't start or you suffer a hot start or even a fire. You have no ground crew support. Evacuation of pax (if required) would be a major problem, considering you may have other aircraft infront and behind you. And the clousure of a whole taxiway (or even the airport) is a possibilty, what with a fire damaged A/C and 160+ pax on the loose near an active runway.


I'd say ditch these drives (it's just something else that needs to be maintained) And your onto a winner.

As for your window at the door being elevated up, it's a nice idea, but can't you just build it into the door? The door is a heavy system anyway...

Good work though!!

Atreyu:ok:

Also while I remember, If one of your wheel drives fails, that could be an embaressing moment for the crew.

Par exemple,

Both crew being 'heads in', say dealing with a problem. (naughty, I know, but not unfeasable is it?) One of your drives fails, and asymetrically, the aeroplane rolls onto the grass. (or water at LCY :*) Or say one of the drives jams up, It could be akin to using full braking on one wheel. ATC frown upon aircraft doing handbrake turns, it's considered a tad rude. :eek:

Also could you dispatch with one inop? Airliners have built in redundency in most systems to allow dispatch with a number of components inop. Would just one of your wheel tug thingies have enough power to move the aeroplane?

If certification deems it necessary that both be working, it wouldn't be fun to ground an aeroplane for something that doesnt even affect it when it's flying!

And even if you could 'switch off' the working one and taxi out on engine power, your defeating the purpose of having them installed. I imagine alot of airlines would eventually remove them anyway. Less cost, weight (and as you've stated; less weight=more pax) and complexity

Just like re-enforced flight deck doors and CVRs for example, manufacturers will only install things when they have to by law. And why? Because the airlines want a machine that is as simple as legally possible.
(granted these are safety related items, but you see my point?)

I know I've banged on about these drives but they just stick out to me as a bit unnecessary.

Just a thought :)

(I always think of failures, too much RJ/146 flying!!! :})

I watch with interest.

Atreyu:ok:

Keesje, my comment re the name was really tongue-in-cheek. That sort of thing is usually done by testing random groups of travelers anyway, not by asking a hoary sampling of ppruners.

In your #58 you said

Quote
If this is to be a 737/A320 replacement dedicated for short high frequency flight, as I stated in the opening post, very short airfield performance is not a basic requirement. It could be an optional package.
Unquote

I wonder. My earlier comment about getting the airplane closer to the passenger really meant getting it into smaller regional airports provided the demographics are right. That seemed sensible to me partly from of the fuel consumption aspect: small airports where turnoff to gate is two-three minutes vs big ones where it could be ten, fifteen, plus holding for other traffic to pass. I realise that would require big rethinking of ATC, terminal facilities, who pays for the new navaids etc but with fuel going the way it is, those little things seem likely to make a big difference in overall operating costs.

I'm probably with Atreyu re electric drives if only based on there being one more thing to go tech.

And I’m totally with mcnuggit re the windows. Hell on the spine having to scrunch down to see outside. Yes you can hear me muttering “Viscount, Electra….”

Atreyu, broadreach, thnx for your ideas. Regarding the failure rate of the electric drive system, I guess a suitable MTBF could be engineered in. If it is not functioning a (slow) push back on one drive should be possible, or a conventional tug could do the job. It's not a no go item.

Still if it works 99.x % of the time it means a dramatic reduction of airport noise & air contamination. It might pursuade airport authorities to allow more flights or at early/late hours or alternative runways. For e.g charter and low cost airlines this would add value compared to existing types.

Of course a lighter simplified ATR / BAE 146 type of gear could be specified. I included it in the sketch.

http://i191.photobucket.com/albums/z...g?t=1210596604

Changes compared to earlier sketch:

• Additional escape window (required)
• Alternative simplified main landing gear
• Wing - engine pylon fairing
• Belly access doors

It would be nice to have feedback from folks from fleet management departments / OEMS. What would be the best way to get their opinions?

turboliner
 

I am sure that this is not the sort of feedback that you are looking for but it may nevertheless be useful. Speaking as a passenger, I used to commute regularly between Lagos/Ibadan/Kaduna/Benin, over a period of 4 years, some time ago.
The workhorse of these routes was the F27 but occasionally an F28 was used.
There was a huge difference in ‘comfort’ between these two. The noise/vibration/harshness of the F27 was not something that one looked forward to. But more importantly, IMO, it was the limited service ceiling or cruising ceiling that made the F27 particularly uncomfortable because most of the time it could not rise above the bumpy air. The type of discomfort I am talking about is not just a regular jolt or two that people nowadays seem to refer to as turbulence. No, this was the real difficult stuff that could pin the cabin staff to the ceiling for a good few seconds, and leave one's hips bruised and chaffed by the seatbelt. I therefore developed an aversion to the F27 and their ilk. In the F28, I could often see the weather well below, and could walk straight when I got off.

Would your design be better than this for comfort? If not, passengers will eventually shun it. The answer is to design one that can get above the weather, easily. Is a 25,000ft service ceiling enough? Wasn't that the service ceiling of the Bristol Britannia in the 1950s? Surely engine and propeller technology has improved since then.

I follow your posts with interest, on Airlinersnet as well, if I am allowed to say that.
rgds

Turboliner
 

Re Jstflyin, the Russians were quite good at it. Have a look at the IL 18 http://en.wikipedia.org/wiki/Ilyushin_Il-18 of 50 years ago. The oxygen mask argument which I have heard or seen before is a bit flat-earth, imo. I like Keejse’s design proposals, but I also like my comfort, and so do most people. Comfort costs money but is appealing to the customer and therefore good for business. The more that can be demonstrated the more likely someone will look seriously at such designs. Is it impossible to incorporate the comfort factor and keep down operating costs? Maybe. But on a much smaller scale Saab appear to be making a good job of it.
rgs P

I assume the door will be >6ft above the ground when on the gate... if that's correct, then I think you'd need means to assist evacuation from the emergency windows (as there is no wing there). Given this, I think a smaller door (739 style) will be better to be put where the emergency exit windows are, or maybe move it clear off the sponsons... as you need a slide from the exit and you don't want it to get poked by the wheelbay door or landing gear mechanism.

Anyways, nice stuff Keesje, although I was wondering if someone would do a mini Tu114 twin... *grin*

Some comments on the aerodynamic configuration, if I may.

Control System Architecture

Looks like the elevator and rudder are manual, or at best hydraulically-boosted manual. (Tabs on both surfaces, horns on the elevators). Yet the ailerons have no tabs of any kind, and you've got "high speed" ailerons, which implies to me a purely hydraulic solution for roll control. I don't think that's a consistent approach; you're going to have to build in a level of hydraulic redundancy to address the roll axis, so you may as well use the same systems for the other axes too.

I'm not convinced of the need for a "high speed" aileron option, nor am I convinced that not having spioilerons is a good choice.

I see no provision for ground lift dumping, other than the slightly oddly located "direct lift spoilers". Why are they so far forward - they are going to infringe on the fuel tank volume sat in the middle of the chord. Usually they'd go just ahead of the flaps so they could mount on the rear spar.

The h tail looks a bit small, as indeed does the rudder.

The wing isn't "dressed" so I'm guessing you're assuming artificial stall protection?

It looks like you've got AI protection only either side of the nacelle - with the new rules for icing that unprotected outboard wing is going to be a real drag, no pun intended. If you're going to leave the wing unprotected you'll need a big wing, and still may have problems.

The wing/body fairing looks too small, just by eye.

Re the emergency exits: maybe you can argue that the UC door is the step-down surface and avoid slides? Need to align the forward exit with the gear door in that case.

Hasn't the idea of Wheeltug" been done to death somewhere else on Pprune? Seems like a needless complication. But, the design does look promising.

GF

Keesje
 

Fascinating effort, just great. I like the DLC (from the 1011?) that mitigates the low level burbling. I think you're off base on the "wheeltug" concept, though. Anything that incorporates ground handling costs in favor of the Landing authority is not a good economic design. In other words, once my aircraft is on the deck, it's a truck. Airplanes are not good trucks (or tugs), and logically it is counter design to try to mitigate what is arguably the ground's duty. I would try to interest others in building new tug designs, vehicles that are more versatile and can be designed to travel (while towing) greater distances. If you look at the cost of carrying around (wheeltug) extra weight, over the useful life of your aircraft, then add maintenance, I don't see the advantage. I guess I'm saying tugs don't fly, A/C don't tug. Offering an expensive perk to the ground authority without payment, is not good business. If you're flying into tugless strips, be happy with your propellors, not your Jet sucking hot pipes. I think you'll like Hotel. Keep going, all the best.

Airfoil

Simplifications
 

Hi Pettifogger, I've flown several times on F27 variants and F28. Both are very loud indeed on the outside and on the inside. Deafening. http://www.youtube.com/watch?v=Vycf4odW1_Y&feature=related A proud dutch product but developped 50 yrs ago.

The new engine / prop I proposed is the TP400. It is developed to turn slower and avoid the typical tip effects and has better turbine noise isolation.. http://www.youtube.com/watch?v=h-V5jzSslZo It will allow the A400M to use civil airways flying M0.7 at up to 37.000 ft.

Apart from that it seems passenger comfort is really moving down the priority list as airlines struggle to survive the constantly rising fuel prices. http://www.iht.com/articles/2008/03/24/business/turbo.php

As said earlier, the shorter the trip, the better the turboprops look. I summarized a selection of city pairs in Europe. More then 700 million people live in Europe, but the more wealthy ones live in the western part, all very close together. As can be seen most major city pairs are closer then 400nm. Very high frequency flights are flown, often even by twin aisles.. Then there are flogs of 737 / 320 aircraft doing low cost flights within the same area. The big hubs are seriously restricted. A different situation then e.g. the US or Asia..

http://i191.photobucket.com/albums/z...g?t=1210977129

Quote:

---

I think you'd need means to assist evacuation from the emergency windows (as there is no wing there). Given this, I think a smaller door (739 style) will be better to be put where the emergency exit windows are, or maybe move it clear off the sponsons... as you need a slide from the exit and you don't want it to get poked by the wheelbay door or landing gear mechanism.

---

PK-KAR good point. The doors won't very very high, but high enough to have some kind of slope. I moved them and made them bigger.

It didn't happen. Antonov studied a 720 seat prop version of the Anteus, but obviously did not build it. Luckely I guess, there would be (even more) deaf old people in Siberia.;) http://video.google.com/videoplay?docid=7136291503511317285&q=&hl=en

Quote:

---

I don't think that's a consistent approach; you're going to have to build in a level of hydraulic redundancy to address the roll axis, so you may as well use the same systems for the other axes too.

---

Mad (Flt) Scientist thnx for your comments. I removed all trims to avoid unconsistancy. I think if one looks close more deatils can be found to be inconsistent. That is because it is a powerpoint concept. On the horizontal and vertikal stabelizers; both are bigger then the similar sized but heavier A320.

Quote:

---

I see no provision for ground lift dumping, other than the slightly oddly located "direct lift spoilers". Why are they so far forward - they are going to infringe on the fuel tank volume sat in the middle of the chord. Usually they'd go just ahead of the flaps so they could mount on the rear spar.

---

The DLC is something different then ground spoilers. They are used inflight to decent is a very precise without changing angle.The lift distribution on a supercritical wing is spread out over the chord. Placing close to the flaps would have limited effect. Aircraft like the L1011, F14 and gliders have a DLC system. The spoilers on the Turboliner are not as big as conventional spoiler and can be fully extended when the gear is on the ground.

On the wheeltug system: most see it as a burden. I guess if you fly an aircraft priorities are reliability and performance. When buying and aircraft and negotiating with airport authorities on landing right & evening slots, rising fuel prices, environment targets, growth and noise pollution, other priorities come in. In terms of weight and reliability electric systems aren't what they used to be (ref. 787). The installation would be a few hundred lbs but save fuel.

Still I changed the design to a conventional ARJ type of gear to satisfy concerns put on the table by many (airfoilmod)

http://i191.photobucket.com/albums/z...g?t=1210982850

thnx for the comments! rgds keesje

I quite like the idea of DLC, but in practice on the L1011 - it wasn't so useful. It was designed to prent big lift changes with small attitude changes on the approach. In practice, it was awkward, added weight, difficult to maintain and was eventually disabled by a lot of L1011 operators. As for the crews, you either loved it or hated it. And when activated, it made the landings somewhat firm in a lot of instances.

Also, have you thought about the effect of positioning the spoilers in the accelerated flow behind the props? If they're used in flight, I reckon you will get quite a bit of buffeting.

Airbus to test electric drives this year on A320.
 

No that you'll have convinced me electric drive maybe isn't a good idea:

Maybe it is a good idea afterall ?

http://www.abtn.co.uk/Assets/Images/Other/wheel.jpg



Dan, I've got to take a closer look at DLC & buffeting. As I mentioned the Turboliner is made to do high frequency short flights from busy airports.

The L1011 was developed nearly 40 years ago without 7-8 approaches a day in demanding airport environments in mind. Fly-by-wire wasn't on the capability list either. (great machine though).

I was thinking on more subtile spoiler system then the conventional big plates killing lift after touchdown. More of a very responsive automated system continuously translating pilot inputs into a combination of various controlsurface movements to achieve smooth height adjustments without gaining speed or changing pitch..

Keesje
 

I think you are on target with DLC. It is an effective enhancement to stability and ride. Don't get too excited about wheel motors. Keep in mind it is early on, and the French (EU) obsession with IPCC and Climate change is a bit behind the curve (not in front). If I had the space I'd offer my arguments against the concept. It doesn't make sense even if the APGW arguments do. My suggestion to all who are interested is to enhance ground movers, they are more in their realm pulling heavy A/C and could be much improved, even to the extent of meeting heavies at the High Speed exit and transporting them to Gate (Stand) with A/C engines shut down. Or for that matter, tugging them out to the penalty box for runup prior to launch.

Turboliners
 

Hi Keesje, Thanks for the u tube and other link. I am partially relieved. I can see the sense in what you propose; just flagging up passenger comfort. I look forward to the increased short sector convenience.
rgds, P

Interesting discussion, some quick remarks (doesn't claim to be complete) concerning the current configuration:

• Range: You have to offer more. Take a look at the history of the Mercure and it's lack of range.
• Weight: Your assumptions concerning the OEW are very optimistic.
• Wing design: Right now not comprehensible.
• Space: During the detailed design-process, it's much easier to scale something down, than adding additional things. From my point of view, there is a lack of space for everything, especially for avionics and several supply units. Possibly, parts of the main landing gear an the wing will extend into the cabin and you have to remove some seats and you have to add an extra row: Add one or two meters of length to be prepared.
• Emergency Exits: The current configuration is inflexible for cabin design. And try to avoid the use of emergency slides.
• "roof top windows": You have allready mentioned the problems concerning high tension. It's not impossible to install some windows, but be prepared for a lot of problems.

MadDog
 

Range?? This a TurboProp and targeted for Medium short Haul with cycle ratio in the 1:1 range or less. Range? Add Fuel Tanks and Switch to High Bypass Fans?? Your Kidding?

Airfoil

I'm not kidding, just trying to find more customers :8.

Short Version of the argumentation:
By offering more range, the airlines could boost their cycle ratio by flying alternatly short hops and medium haul routes.

MadDog
 

But then all your accomplishing is carting around unnecessary Fuel. Parallel to my Wheel tug argument: Why carry around in the air that which is better suited at the Gate (or in the Truck)? If your long sector includes stops, assumed, otherwise buy n Fly 73-, then Uplift on the go. The most expensive place to store fuel (or a tug) is ONBOARD.

Shrink option, TP400 engines further testing testing picture
 

#1 Many people say the Turboliner as specified might be too big. I envision the Aircraft as a direct 737 / A320 replacement on shorter stretches <800nm4), not for long stretches. The A320 /737 are optimized for routes up to 3000nm.

Obviously offering a shrunk version of the Turboliner, would be an option. Europrop says the TP400 has growth potential so a future stretch would be possible also.

I sketched a shrink of about 150 inch / 5 seatrow / 30 seats.

http://i191.photobucket.com/albums/z...g?t=1213606107

#2 the TP400's first flights in getting closer finally. The Herc that has been modified is doing test runs (photo flightglobal). Note the additional struts that have been added to transfer loads/moments, damp vibrations, add structural stiffness or a combination..
A part throttle setting at lower speeds / take-off seems neccessary.

http://www.flightglobal.com/blogs/fl...gine%20run.jpg

http://www.flightglobal.com/blogs/fl...run%20zoom.JPG

Keesje
 

I've followed your work and think highly of it. With respect I'd like to play Devil's advocate for a moment. Your attention to detail is impressive, and you innovate on the fly, a very admirable quality in design. Let me ask you a couple simple and sincere questions. The Hercules is approaching sixty years of age, yet is present in large numbers, relied upon by both military and civilian owners, and has a pedigree and fact sheet that remains unequalled in many ways. Would you discuss by way of affirming your approach the need for wildly complex "improvements" and "tweaks" when an airframe of the 130's record of performance stands alone? Imagine 13k horsepower per side and fans you propose on an airframe that can be configured to carry ~250 pax (or more) transcontinental? A Twin Herc? Again, this is what if? To further Frame your work, if you will.

Airfoil

airfoilmod
 

thnx for your kind words. I agree with you the C130 has a place of its own. I think it is becoming clear to its operators that its cargo deck and load carrying capasity is reaching its limits. Airforces want to move heavier / bigger equipment than the C130J can handle.

Its 20t capasity doesn't have much competition, the A400 is significant larger, the C27 significant smaller. The Brazilians smell an opportunity and seem to step in with the C-390 that has already attracted interest.

http://sistemadearmas.sites.uol.com.br/ca/macxc3901.jpg

For passenger use I think a good militairy cargo aircraft will have a hard time becoming a good passenger aircraft. A big cross section / large cargo deck & heavy landing gear seems to contradict low drag / frontal surface. Then there is big door in the back. Structural weight & aerodynamics are probably not optimal for passenger service.

News today is that GE foresees its new heavy 8000 hp turboshaft under development for the CH53K to potentially play a role on fixed wing aircraft..

GE plots GE38 engine's future in emerging heavylift market