Testing update: Due to a chassis-related issue, we have had to change the power unit as a precautionary measure. The team is pushing hard to get the car back on track before the end of the session
Re: Honda Power Unit
Posted: 15 May 2018, 17:30
by Thunder18
Why would chassis affect PU so drastically?? Is it Hartleys chassis??
Testing update: Due to a chassis-related issue, we have had to change the power unit as a precautionary measure. The team is pushing hard to get the car back on track before the end of the session
Worth noting that they successfully got back out again - they did the PU change in < 2 hours.
Testing update: Due to a chassis-related issue, we have had to change the power unit as a precautionary measure. The team is pushing hard to get the car back on track before the end of the session
Worth noting that they successfully got back out again - they did the PU change in < 2 hours.
Great to hear. Any signs of a newer spec being used?
Seeing as the compressor is essentially unlimited aside from being a single stage centrifugal compressor, is there any chance microjets could be used to further optimize the compressor blades, volute etc, or the intake ports in the head?
"At the high Mach number case (M=0.4), the use of microjets appears to eliminate the shock structures that are responsible for triggering the shock-induced separation, establishing the fact that the use of microjets is effective even in controlling dynamic stall with a strong compressibility effect. In general, microjet jet control has an overall positive effect in terms of maintaining leading edge suction pressure and preventing flow separation."
"The laboratory results show that the microjet actuators are an effective means of controlling separation with fairly low supply pressures and flow rates. Only relatively robust and straightforward diagnostics can be used to determine the flow conditions on the UAV during flight. As such, tufts are installed on the aircraft’s wing to serve as a qualitative way of measuring control efficacy. Results from the flight tests confirm that this flow control system is capable of delaying flow separation in the complex flows occurring during flight."
Nice!
No doubt the compressor useable flow region could be extended (moving the surge line to the left) - if it was possible to produce the intricate galleries and the nozzles themselves near the leading edges of the blades. 3D printing would do it! Compressor discharge pressure would be sufficient to drive the micro-jets.
Re: Honda Power Unit
Posted: 16 May 2018, 13:02
by dren
Yes, that is an interesting idea on the compressor. It'd have to be purely passive, right?
Yes, that is an interesting idea on the compressor. It'd have to be purely passive, right?
Need to run galleries (green) through the compressor impeller and connect to the compressor discharge. All internal to the compressor design so should be considered "passive".
Yes, that is an interesting idea on the compressor. It'd have to be purely passive, right?
Need to run galleries (green) through the compressor impeller and connect to the compressor discharge. All internal to the compressor design so should be considered "passive". https://i.imgur.com/7JnZavw.jpg
Any educated guesses on efficiency loss by doing this?
Surely the holes in the blades and the fact that some of the air is being compressed more than once as it gets recycled through the compressor will heat it up more.
I have to wonder if this will work better than simply having variable stator vanes pre compressor as are used in many gas turbines already. That would also move the surge line to the left.
IRC I had asked about this before and was told that variable geometry was allowed only banned on the exhaust side not the intake side.
Yes, that is an interesting idea on the compressor. It'd have to be purely passive, right?
Need to run galleries (green) through the compressor impeller and connect to the compressor discharge. All internal to the compressor design so should be considered "passive". https://i.imgur.com/7JnZavw.jpg
Any educated guesses on efficiency loss by doing this?
Surely the holes in the blades and the fact that some of the air is being compressed more than once as it gets recycled through the compressor will heat it up more.
I have to wonder if this will work better than simply having variable stator vanes pre compressor as are used in many gas turbines already. That would also move the surge line to the left.
IRC I had asked about this before and was told that variable geometry was allowed only banned on the exhaust side not the intake side.
So why not variable stator vanes?
Indeed. That fact that VSV are in use would reduce the potential for gains from microjets. Add to that the compromises in impeller design and possible efficiency reduction. I say "possible" because the factors (heating etc) you raise, are minor. These are tiny holes and flow is equally insignificant. OTOH any reduction in flow separation will improve efficiency although - again - the VSV system should minimise that anyway.
Re: Honda Power Unit
Posted: 22 May 2018, 17:32
by flexcon
So I found this video I put together from testing. Forgot to share and post.
Honda engine sound from multiple angles- Pure Sound only. Enjoy
