Boeing at X-Roads?

[fdr]

Originally Posted by petit plateau

fdr,

I am in wild agreement, hence my more generic comment about different thrust devices and different energy sources, and also regarding potential changes in the underlying travel market.

Tell me, regarding your thrust widgetry which you seem justly proud about, how would it fare if the energy source was not burning long-dead dino juice ? Would your widgetry still be at all relevant, or would one design 180-220 seat aircraft around other thrust devices ?

If you were an airframer considering a market entry would you jump in now, or hold back ten years and wait and see ?

And in the meantime am I right in guessing that you see your widgetry as being most interesting in sweating the existing fleets to perform better, rather than switching out for new fleets entirely ?

regards, pb

Petite P;

My text Is agnostic to the manner that torque is applied to the propeller, rotor or fan blade. The engine is either purely a source of tprque to spin a shaft that does something to generate a force and hopefully achieve some work output. Electric, hydrogen, SAF, Jet A, or white spirits, it doesn't matter.

While I am pushing ahead with the STC for props and the turbo fans that I have funding or JV's to cover, and that is a major effect on CO2 and NOx, I am not a proponent of electric propulsion for aircraft use at present. The fundamental problems of a plug in electric motor is the risk in accidents; they have a significant fire risk that appears to be difficult to mitigate. Hope that Toyota gets somewhere with their onboard electrolysis processing, but not certain the enegy balance works, unless they have some seriously magic ceramic catalyst tech in the background. In the absence of that, it seems that using renewable electric harvesting to generate hydrogen in a distributed network would allow a move towards FT, CO added ethanol, which may avoid having to disinvite a number of the citizenry from eating and living on this fair planet.

The rate of CO2 addition is an issue, as is NOx, particularly where we inject it into the atmosphere. Cycling CO2 within a loop process to give a high energy density fuel still seems to make sense IMHO.

boring stuff

Spoiler

 

 

As far as application of technology goes, my old B737 CL would burn around 2.4 T/hr when we started the first STC series win that. I took just on 5% off that, with a simple STC to circumvent the mess that the slat trailing edge makes of the boundary layer. That particular mod is fairly sensitive to AOA, so the operators had variable outcomes. The propeller works on any prop, the higher the TAS, the better. The fastest we have run to date was on a heavily modified P51, but my old T28B ran along at 330KTAS, so was analogous to the C130 54H60 prop. We have a JV underway for the C130/L100-30. The prop is only around 20% increase in thrust, and yes, that makes for some weird math when considering the efficiency the propulsion system. For what it's worth, the greatest effect we get is where there is transonic or sonic flow, that is where stuff goes really fun. Shocks mess up efficiency, directly and indirectly. The B737 mod was shock suppression, what we are doing now is shock avoidance, and that really is a neat trick. The greatest change in efficiency occurs when the prop or fan blade is transonic, or sonic. The Classic burns 2.4T/hr as said, and we are already demonstrating around 1/3rd reduction in FBO, so that gives about.. 1.6-1.7T/hr, for a well worn, amortised, end of life aircraft type. It is at the end of life due to efficiency, and SSID/CPCP long term costs, but, for 3-5M vs 110 M for a Max, which might have a few more seats and nicer interior, and will burn more than the classic? We shall see. We have given a briefing to Airbus, and that is necessary; system integration is more complex with the thrust management system on the Airbus and the EMB 170-195 series. Boeing's are straightforward integration, as are the CRJ, ERJ and earlier A300/310's. The latter is however still of concern my little turbo fan outperforms my earlier bunsen burner baby Learjet which was fun to fly itself. Limiting TO thrust is straightforward but has raised some curious paradoxes; §33.27 provides the requirements for TO/GA time limits, yet operating at lower RPM and EGT than MCT will achieve the same thrust up to a but below 10,000' PA ISA +15C, so thats weird.

Our interest is towards STCs for the existing designed props rotors and fan blades. This technology does not apply to the core flow at this time, and I am not prepared to go below 2.3 BPR, that was hard enough. Bigger is better. It is agnostic to titanium, hollow or CFRP blades, all current designs are applicable. The only design that caused grief was a 1m fixed pitch folding blade which had an outer blade angle that was weird. The outcome sucked, we got 17^ higher thrust, static, but fore the first time that was at a lower TSFC. Sucked. Eventually got an 8% efficiency gain, static. Being fixed pitch, the efficiency in flight was quite different, but it was head scratching until a close look at the blade AOA was conducted.


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