Russia needs a reliable, in service jet, more than it needs a higher efficiency jet on the drawing board. If you look at Leap engines vs GTF, I think it's pretty obvious that the gear box is a long way from perfect.
That Geared TurboFan Engine has bankrupted airlines. My take would be - less complications, more simplicity, better materials and structures, easier maintenance and operability.
"To reduce maintenance costs and increase reliability no transmission will be installed." From about 56 seconds into the video you explain why no gearbox is included. 1 minute 12 seconds: "Modern design solutions are applied to simplify the design and achieve fuel efficiency". Kinda makes any questions about whether to add a gearbox redundant doesn't it? The Old engine wasn't French, it was a Russian French collaboration. They know how to make new engines. Not a good time to add complication to the engine at a time when it is needed in aircraft. It will also be used in the Il-212 which is the scaled up Il-112 with jet engines in an overwing position essentially becoming a replacement for the An-72.
PD-8 is twin-spool design so doesn't need a gearbox to run the front fan at diff revs to the hot core. That PW engine you mention on the A-220 is 50% bigger diameter front fan than the PD-8/Sam-146. So it has planetary gears due to issues with the tips of the fan blades speed getting too high. A-220 is an usual spec 5-abreast seating for 200 passengers .... Russia has no aircraft that size so there is no need for a geared PD-8 version.
Optimising the performance of the engines at takeoff and landing to improve efficiency sounds like a rather short period of time for it to be efficient. This engine is 3% more efficient than the Sam engine in flight so even if it is less efficient at landings and takeoffs it is still better and would be simpler and lighter and more reliable without the gearbox added. I don't think Safran will make them a gearbox so that might be a few years getting a gearbox developed and made and reliable. Not worth the delay. If gearboxes are so amazing they can get the engine ready and in service and then work on a gearbox over the next few years to make it even better.
If today in mid Jan 2025 the final design of PD8 is not reached, this says Russian civil aviation would suffer further crippling delays. To put PD8 on aircraft routes this will not be before mid 2027. I am sorry for that
Gear turbofan is a source of problem. And it is not new tech anymore. It was used in Honeywell Garrett's engine for so long. One of the SSJ failures is that engine problem. Customers claim it is unreliable and fail short in maintenance. Russia said it was from the French engine parts.
Sukhoi can easily put a geared ducted turboprop like the Kusnetzov NK-173 with counter rotating blades to instantly get a 25% fuel savings more than the said engines.... The sky is the limit....
Russia needs a reliable, in service jet, more than it needs a higher efficiency jet on the drawing board. If you look at Leap engines vs GTF, I think it's pretty obvious that the gear box is a long way from perfect.
That Geared TurboFan Engine has bankrupted airlines. My take would be - less complications, more simplicity, better materials and structures, easier maintenance and operability.
...less weight
"To reduce maintenance costs and increase reliability no transmission will be installed." From about 56 seconds into the video you explain why no gearbox is included. 1 minute 12 seconds: "Modern design solutions are applied to simplify the design and achieve fuel efficiency". Kinda makes any questions about whether to add a gearbox redundant doesn't it? The Old engine wasn't French, it was a Russian French collaboration. They know how to make new engines. Not a good time to add complication to the engine at a time when it is needed in aircraft. It will also be used in the Il-212 which is the scaled up Il-112 with jet engines in an overwing position essentially becoming a replacement for the An-72.
Two parts of turbines a low speed high torque axel and a common compressor turbine axel gears are absent but for generators and pumps
PD-8 is twin-spool design so doesn't need a gearbox to run the front fan at diff revs to the hot core. That PW engine you mention on the A-220 is 50% bigger diameter front fan than the PD-8/Sam-146. So it has planetary gears due to issues with the tips of the fan blades speed getting too high.
A-220 is an usual spec 5-abreast seating for 200 passengers .... Russia has no aircraft that size so there is no need for a geared PD-8 version.
Optimising the performance of the engines at takeoff and landing to improve efficiency sounds like a rather short period of time for it to be efficient. This engine is 3% more efficient than the Sam engine in flight so even if it is less efficient at landings and takeoffs it is still better and would be simpler and lighter and more reliable without the gearbox added. I don't think Safran will make them a gearbox so that might be a few years getting a gearbox developed and made and reliable. Not worth the delay. If gearboxes are so amazing they can get the engine ready and in service and then work on a gearbox over the next few years to make it even better.
If today in mid Jan 2025 the final design of PD8 is not reached, this says Russian civil aviation would suffer further crippling delays.
To put PD8 on aircraft routes this will not be before mid 2027. I am sorry for that
Gear turbofan is a source of problem. And it is not new tech anymore. It was used in Honeywell Garrett's engine for so long. One of the SSJ failures is that engine problem. Customers claim it is unreliable and fail short in maintenance. Russia said it was from the French engine parts.
The Sam Engine is much older than the PD8 .. there's a possibility that the gear box was intentionally excluded..
We have not seen any reference of the PD8 test flight on the Flying lab!!!! can u prove me wrong >
those who can do ,those who can t, criticize. nobody have to help Russia ,they wil do the neccessary adjustment.
It will be if it lowers maintenence requirements...
Sukhoi can easily put a geared ducted turboprop like the Kusnetzov NK-173 with counter rotating blades to instantly get a 25% fuel savings more than the said engines.... The sky is the limit....