The ability of any upgrade to achieve sufficent payload to meet the key lift requirements for 3 Cdo Bde is clearly essential to the credibility of the Merlin in achieving the task...as several of the previous messages have stated.
There are significant limits to how much extra power/lift can be provided in the present design - and these too are not going to be without some signifcant cost of ownership issues being raised..We have discussed the "dead" weight of the 3rd engine before, but more critically in this context are the limitations associated with the MRGB design, and the tail rotor stresses and authority.
In short, in the earliest designs of 101 as originally conceived by Westland alone, it was to have an advanced composite MRGB design which would have provided more than ample power capacity, and for "future proofing" given the accepted wisdom that op lift demand suffers annual inflation particulary if real ops are a regular part of the equation. The final MRGB design chosen was a result of Agusta having to have it as their part of the 50/50 workshare balance required and to cap programme costs...and a very conventional design was chosen with more limited capacity for development and torque/power capacity increases.
In the end the whole Advanced Engineering Gearbox (AEG) design was binned by Westland (also as a result of MoD's cancellation of the concurent W30-404 programme which was conceived to use it too) as the money and sponsorship dried up...great shame for them and UK plc.
Tail rotor stress and power issues have been with the 101 from Day 1, and despite cost efficient enhancements to deliver both safe and effective performance, and fatigue control, this issue also remains to inhibit just how much can be done to increase MAUW and associated performance and maneouverability. The Mk2 will gain in the short term as its APS weight is about to reduce following the MCSP misson system and cockpit integration, but the Mk3 (Mk4?) is going the other way particularly when you translate this into the more demanding wind over deck/SHOL issues associated with regular maritime ops (at the higher AUMs)...and one can see that achieving an effective release will be at the very least, demanding, relatively expensive, and may in the end not meet all the Cdo Bde's lift expectations.
The alternative, if really substantial development and performance improvement is to be made, is a return to the AEG and a new tail rotor design (actually an old one but never incorporated due to previous budget limits)...Will this ever happen given the very large cost associated with these modifcations..certainly not in the present financial environment....so here we go.
Last edited by Tallsar; 18th Jan 2011 at 17:37.