Re: Hawker siddeley trident wing

Dear all, Thank you very much for these insights. I definitely learned something. Now I'd like to ask, how do they design the "automatic pitch down in a developing stall" in a straight wing, e.g. for the Q400 or ATR? A higher pitch angle at the wing root wouldn't change the center of lift...

Re: Hawker siddeley trident wing

Here is the best I have: This is a very interesting drawing. Take a look at the obvious wing twist from the root to the tip. The angle of attack is significantly higher at the root. Would this design feature induce a stall behavior where the root stalls first, moving the center of lift backwards, t...

Re: Hawker siddeley trident wing

Here is the best I have: This is a very interesting drawing. Take a look at the obvious wing twist from the root to the tip. The angle of attack is significantly higher at the root. Would this design feature induce a stall behavior where the root stalls first, moving the center of lift backwards, t...

Re: Question about brake and rudder pedals.

The braking pivot point is towards the bottom of the pedals, not the middle. The whole thing is quite easy to get used to. Within half an hour or so in your first light aircraft it becomes second nature to steer and brake with your feet. Just wondering if you ever get confused switching between coc...

Re: ETOPS certification of passenger-to-freighter converted aircraft

ETOPS is a costly status to maintain if you don't really need it. There is a lot of training and record keeping. Many of the aircraft's components require specific maintenance, which is an added cost. These components are in just about every system that would cause a plane to divert. Yes that inclu...

Re: The manufacturing of the current 767

I've always wondered on the 757 and 767 there were two types of throttle lever design. A slimmer grey set, tended to be on earlier builds and a bulkier burgundy set on later builds. Was this dependent on engine type? I know the the RR on the 757 and earlier builds the engines were mechanically link...

Re: Non-Operational Reasons That Seats Might Be Held Back From Sale (United Express)

A CRJ-200 has an average empty weight of 31300 lbs - each aircraft is different Max Takeoff Weight is 53,000lbs, max landing weight is 44,000lbs, max zero fuel weight is 47,000lbs So we are going on a flight from RIW to DEN a distance of 274nm along a routing of KRIW TOFUU.FLATI3 KDEN enroute fuel ...

Re: ETOPS certification of passenger-to-freighter converted aircraft

Many variables in play here. Is ETOPS required for freight? I don't think it is, but I might be all wet. It might be a local requirement for certain freighters. The A/C that kept ETOPS during conversion may be subject to leasing terms, where the residual value of the A/C is less without the ETOPS c...

Re: Turboprops vs Turbofans.... and Propfans!

As far as I remember, service ceiling is a significant factor. Dash-8 and ATR are limited below FL300, while RJ can go over FL400. Are you aware it's not a powerplant limit, but a general choice of aerodynamic efficiency vs payload vs range? There are turboprops able to go way above F300. Dash8 and...

Re: Turboprops vs Turbofans.... and Propfans!

what about "above the weather" part - can you comment? It all depends on where you're flying. In Alaska or Northern Canada the low 20s is plenty to get you above 99% of the bad weather even in the summer; I can remember only once in several years being faced with a line of thunderstorms (...

Re: 787 vs A330 Runway Performance/Requirements

Pilots are conservative creatures and in the decades gone by where we did on occasion use charts, there was excessive rounding up and intercalation. As much as we would like to have very precise data, my impression is that even using an app or other electronically calculated data, there is still co...

Re: Turboprops vs Turbofans.... and Propfans!

Very empty RJ above F400, certainly no CRJ. Very true, spoken from experience. Mid-high 20s was our typical domain; even 310 was a struggle. Did 370 once but that was on an empty repo flight so it really doesn't count. WHat is the usual cruise of a turboprop? Service ceiling is an official number f...

Re: 787-10 floor vibration

Took a BA 787-10 flight from SEA to LHR some months back and was in 13A which is towards the front of the wing. As we got into cruise I noticed a really uncomfortable vibration cycle, similar to what I often feel on ships/ferries as best I can describe it. It was over about 8s or so as I remember, ...

Re: 787 vs A330 Runway Performance/Requirements

I would think manufacturer charts are for best case situation in terms of runway performance. Actually, Boeing chart specifically shows what flaps settings are being used at which conditions, so they must have some idea about flaps effect. If you choose to trade in longer roll for less engine wear ...

Re: Turboprops vs Turbofans.... and Propfans!

GalaxyFlyer wrote:

Very empty RJ above F400, certainly no CRJ.

Re: Turboprops vs Turbofans.... and Propfans!

As far as I remember, service ceiling is a significant factor. Dash-8 and ATR are limited below FL300, while RJ can go over FL400. As a result, there is a non-insignificant pool of cases when RJ can go above the weather, but turboprop has to go around the weather, burning more gas and subject payloa...

Re: 787 vs A330 Runway Performance/Requirements

Probably minimal possible runway meaning max thrust. Although one thing to keep in mind - MTOW bumps without thrust bumps mean more runway, and at the tail end of the curve even small weight increase means a lot more concrete. A bit of thrust increase may shorten the roll significantly. Early versi...

Re: 787 vs A330 Runway Performance/Requirements

I doubt you'll get a direct answer. Here is an attempt, though. Below is comparison of performance data from airport planning manuals. A332 with PW4000 vs 787-8 with "high thrust rating". x-axis is adjusted so that scales match. "High thrust engines" (shown) version has a bit sh...

Re: 787 vs A330 Runway Performance/Requirements

I always wondered, is there any difference in the takeoff performance of both aircraft in most conditions. If there's a noticeable difference, who's the better performer? I have heard people say the 787 is a runway hog, but I remain unconvinced by that as there's not much evidence to such claims. I...

Re: 787 vs A330 Runway Performance/Requirements

Design is based requirements, no reason to go beyond the regulatory requirements. Akin’s Laws of Engineering Of course, and if requirements are set by bureaucracy, then results are primarily bureaucratic. However, I suspect quieter new generation is partially due to going beyond minimum, although f...

Re: 787 vs A330 Runway Performance/Requirements

It’s not “shut up”; it’s that there’s a process to evaluate aircraft noise signatures, present them in a form usable by anyone that needs to test for Stage II or III compliance and for compliance with airport noise rules, whichever is more restrictive. See KSNA or YSSY night time curfews. I chose Y...

Re: 787 vs A330 Runway Performance/Requirements

And, “good enough” is just that. No one needs to know frequency, noise source down to a overfill drain, except perhaps engineers tasked with identifying sources and fixes. The public, Airport Operators and crews don’t need it. The standard is for basic comparisons. No operation in actual aviation w...

Re: 787 vs A330 Runway Performance/Requirements

Who are going to believe, scientific engineering data or your lying ears? I don't see any scientific data in the TCDSN. It is a totally bureaucratic document. I see tables of measured noise levels, not a bit bureaucracy. Specifically, flyover noise level at different mass. https://www.easa.europa.e...

Re: 787 vs A330 Runway Performance/Requirements

GalaxyFlyer wrote:

Who are going to believe, scientific engineering data or your lying ears?

Re: 787 vs A330 Runway Performance/Requirements

Guys, I get it. I'm just saying that it's a little strange that they are always lower and significantly louder departing after 10 pm in an area that has one of the highest noise complaint rates in the country. I understand weights, derated takeoffs, climb profile efficiencies, fuel cost, etc. One o...

Re: Turboprop Airliners and Blade Failures

Regulation mandates modern Turbofan engines to have a containment duct which encloses the Fan cowling area of the engine. Shouldn't the ice shield also designed as a protection device in case of prop blade liberation.? That pretty much means converting prop to the turbofan for a very different set ...

Re: Turboprop Airliners and Blade Failures