JayinKitsap wrote:
I am aware that the core of the 1700G is the same as the 1900G and is the reason why the engine is relatively heavy for the E2-175. Is the 1900G core the same as the 1500G or somewhat reduced.
Is there a different core in the 1500G compared to the 1100G? or the same? Which aircraft got the best optimized core theA320 or the A220. If the A220 it part explains its great economics.
It is unfortunate that the RJ and BizJet markets do not have enough volume to get a PW GTF engine optimized for it, but probably not enough volume to justify the expense. The 'elephant' engine order for the B-52 RFP with 608 engines is certainly changing the economics for the winning order.
The PW1900G is the same mechanical engine, but with different externals. Now, I do not know every part, what I know is the anti-ice pneumatic system is quite different and naccle is custom. But the basic engine is the same: Fan, gearbox (same with PW1700G sharing the same gearbox, Pratt will only do a few variations of this expensive to certify sub-system), low compressor, combustor, high turbine, and low turbine.
The fuel injectors look physically the same, but as the flow vs. pressure is slightly different, so they are not interchangeable part numbers. Actually, they might have a different "boss" or hole pattern to prevent mis-instillation... I don't know (nor do I really care about such a common and trivial difference, if I try to remember everything, I remember nothing).
The PW1100G core is not only larger, it is engineered to be a bit more advanced to reduce fuel burn. This is minor, but there is more engineering to cut cooling of the combustor and turbine to allow a little more energy to be extracted from the high turbine which allows a slightly longer blade shape in the high compressor to allow for a higher pressure ratio beyond the free advantages of efficiency a larger core provides (more flow path area to blade and sidewall area improves compressor, combustor, and turbine efficiency. Ok, technically improves losses in the combustor, but as that is engine efficiency, at the systems level it is discussed as an efficiency improvement even though technically it is a reduction in losses...).
The A320 core has a fractionally lower TSFC. It is hard to answer on PW1500G vs. PW1100G for efficiency as for the A319NEO and A320NEO the PW1100G, a 35k engine, is just ridiculously oversized and therefor not as efficient for those frames. Ok, cruise thrust numbers matter, but as I don't have great links to compare, I'll talk takeoff. The PW1100G was sized for 35k of thrust for the A321. It is an amazing engine for the A321. Part of the reason the A321NEO is doing so well is both engines were optimized for that airframe instead of having reduced overhaul intervals as like on the A321CEO (which really pushed the A320 engines beyond their durability limit). So if we are comparing the theoretical A225 vs. A320NEO, the A225 will have a huge climb fuel burn advantage, about matched cruise (due to the PW1100G having a more advanced core, despite being mis-sized). But the A220 has fuel saving subsystems (vs. the A320), so one would expect the A225 vs. A320:
1. A225 to have a climb fuel burn advantage due to the engine better optimized for climb (1.5 hour mission vs. 2 hour mission means the lower bypass ratio improves climb fuel burn).
2. The A225 to have a cruise fuel burn advantage all due weight of the aircraft (engine and airframe, the PW1500G is lighter) and aircraft subsystems
3. We would expect the PW1500G to have a reduced overhaul interval interval as the engine will be really pushed for takeoff and climb.
What will really matter, in the long run is airframe limit of validity. I'm being
In my opinion, the A220 must extend the limit of validity. The A320NEO has a 60,000 flight cycle (FC) and 120,000 flight hour (FH) limit of validity.
Going from memory, the A220 is 60,000 FC and 90,000 FH. The wing and tail section (where shock waves occur) tend to be the flight hour limit I see both airframes having high growth in flight hours. I also believe the A220 should be able to easily go to 80,000 FH, we discussed in the link below. A CFRP wing has practically infinite FH capability, so it will be where shock waves form around the tail on the A220 that limit its limit of validity (as that is where cracks will form. The A320 will have both the wing and tail area limit the FH limit of validity, but I believe the Airbus design philosophy is good for 180k FH).
viewtopic.php?f=3&t=1411871&start=150The A320 failed on extending limit of validity to 90,000 FC and 180,000 FH, discussion showed it probably failed on flight cycles. I speculate by 75,000 FC, but I do not know. All we know is there was an AD due to the failed test to look for cracks (that is the cost of extending LOV, there are always problems found. Does the extended life extend enough of the maintenance to save more than the added inspections and expected repairs?). We couldn't prove anything (in particular, how many cycles the failure happened at). However, I've been involved with aircraft testing and it would have been weird not to do a midpoint inspection and if that had passed, Airbus would have extended LOV to 75,000 FC and 150,000 FH. So I speculate the failure was found at 75,000 FC and 150,000FH. I wouldn't have done an earlier inspection (inspections require a team of 200 to 300 supporting degreed engineers for months and so you are paying the cost of 100 engineering years per inspection or about $25 million plus rent on the stand plus you have to delay other engineering projects to have those engineers do inspections, take photos, and do tons of analysis and reports and probably a small repair or two that becomes an AD). The airbus A320 cracking was far too pervasive to repair.
Due to the location, there is no chance it was hours, it would have been stress due to flight cycles in my opinion.
viewtopic.php?t=775787I believe the A220 could easily make 80,000 FC and 160,000 FH.
I personally would go for 80,000 FC and 120,000 FC and do a full inspection. Then I would push on to 90,000 FC and 160,000 FH (I believe due to the CFRP wing and other design details, there is little to no risk on FH and more than 160,000FH has no value in a narrowbody, in my opinion. Two links ago I talk about JetBlue flying 11.3 hours per day in the A320:
http://investor.jetblue.com/~/media/Fil ... r-10-k.pdfWith the added range, I see no reason they won't eventually fly a lot more long thin, possibly even TATL thanks to the PiP this thread was started on. (1 class to LCY? I can hope... I know, pipe dream.) Plausible as the A223 certainly has more range than the A320CEO during that timeframe.
So 11.3*365 is 4124 flight hours. So in 20 years 80,250 (rounded up, just a smidge). So you might go why? Extend those service intervals to the full corrosion interval of 12 years (oh wait, it would be 1/3rd of service or 160,000/3 or 53,333 hours or ... just over 12 years. Only Hawaiian would complain about a 90,000 FC life as they would wear out an aircraft in 18 years. A thread discussing high utilization aircraft:
viewtopic.php?t=1390723A hattip to wrongwayup who found the highest utilization narrowbody (I copied his post and would expect some aircraft now to exceed these numbers):
In-service 737 fleet leaders:
737 hours leader: 81,097 FH. Magnicharters 737-200 MSN 22652 XA-MAD
737 cycles leader: 76,906 FC. Air North 737-200 MSN 23122 C-GANV
All-time 737 fleet leaders:
737 hours leader: 102,227 FH. WestJet 737-200 MSN 20807 C-GUWJ
737 cycles leader: 97,326 FC. WestJet 737-200 MSN 21117 C-GWJU
In-service A320 fleet leaders (both are still in service):
A320 hours leader: 87,011 FH. Air Canada A320 MSN 68 C-FDQV
A320 cycles leader: 53,997 FC. Lufthansa A320 MSN 72 D-AIPD
I believe someone posted a higher cycle DC-9 than the 95k FC I posted a link on in the thread, but I'm not finding a link. As so few aircraft break 80,000 FC, there really isn't any present value to selling a new aircraft with a high LOV. I do not see any aircraft needing more than the 120,000 FH of the A320, I propose an extension to stretch out maintenance intervals to help sell aircraft, not for service 40 years from now.
So if Airbus only extends the A220 to 80,000 FC and 120,00 FH, that is plenty (happens to be the CRJ limit and that was a required extension from 60,000/90,000).
At this time, the A320NEO has a cost advantage on flight hours and I believe that is enough to drive sales for the next decade, so any LOV extension on it won't be for a while (there is no economic push, at this time). In fact, it might be just for a re-winged variant (with say a material change in the area that cracked before and areas that might crack to go for that 90,000 FC 180,000 FH). But that quickly is off topic...
I'm going from memory, but isn't the E-jets a weird 72,000 FC, 90,000 FH? Due to thinner wing sheet metal (at select locations), I don't know about the feasibility of extending their LOV, but I'm also not certain it is needed either (in other words, I think they are 'good enough' to not impact sales campaigns). Mostly, I'd like to see more cycles on the A220 as that seems to be what A320s are being retired upon. If I were Airbus, I would invest, after the initial PiPs and manufacturing fixes, in 80,000 FC/120,000 FH. It is only speculation, but I believe that is a very low risk, but expensive, PiP. (Total testing budgets, going from memory, routinely exceed $200 million.)
Lightsaber