If this is your first visit, be sure to check out the FAQ by clicking the link above. You may have to register before you can post: click the register link above to proceed. To start viewing messages, select the forum that you want to visit from the selection below. |
|
|
Thread Tools | Display Modes |
#11
|
|||
|
|||
Hyabusa flat 8
On 6 Mar, 11:03, bod43 wrote:
On 5 Mar, 21:57, "Morgans" wrote: snip interesting stuff Maybe someone on uk.rec.motorcycles might have an idea as to the expected life span of a hyabusa engine when operated in a constant load regime, say at 130bhp. You'd need to boost the low and midrange torque to swing a prop, as props rotate relatively slowly, don't they? I think a 'Busa engine would last forever is detuned to 130bhp. A Gold Wing 1500 or 1800 lump might be more suitable, IMHO. |
#12
|
|||
|
|||
Hyabusa flat 8
Using the patented Mavis Beacon "Hunt&Peck" Technique, "TOG@Toil"
typed On 6 Mar, 11:03, bod43 wrote: On 5 Mar, 21:57, "Morgans" wrote: snip interesting stuff Maybe someone on uk.rec.motorcycles might have an idea as to the expected life span of a hyabusa engine when operated in a constant load regime, say at 130bhp. You'd need to boost the low and midrange torque to swing a prop, as props rotate relatively slowly, don't they? I think a 'Busa engine would last forever is detuned to 130bhp. Depends on the prop, but I would think that gearing down would be the way to go. -- Wicked Uncle Nigel - "He's hopeless, but he's honest" It's important is that last ell. |
#13
|
|||
|
|||
Hyabusa flat 8
Wicked Uncle Nigel wrote:
Using the patented Mavis Beacon "Hunt&Peck" Technique, "TOG@Toil" typed On 6 Mar, 11:03, bod43 wrote: On 5 Mar, 21:57, "Morgans" wrote: snip interesting stuff Maybe someone on uk.rec.motorcycles might have an idea as to the expected life span of a hyabusa engine when operated in a constant load regime, say at 130bhp. You'd need to boost the low and midrange torque to swing a prop, as props rotate relatively slowly, don't they? I think a 'Busa engine would last forever is detuned to 130bhp. Depends on the prop, but I would think that gearing down would be the way to go. The thing that everyone seems to forget when promoting automotive engines for aircraft is that most piston aero engines have a very hard life. Take-off and climb is full power or very nearly, then they throttle back to cruise at 75% or thereabouts. The only roadgoing vehicles that approach that sort of use are in motorsports, and how long do they last? |
#14
|
|||
|
|||
Hyabusa flat 8
On Fri, 06 Mar 2009 13:40:21 GMT, "platypus"
wrote: The thing that everyone seems to forget when promoting automotive engines for aircraft is that most piston aero engines have a very hard life. Take-off and climb is full power or very nearly, then they throttle back to cruise at 75% or thereabouts. The only roadgoing vehicles that approach that sort of use are in motorsports, and how long do they last? They last as long as they have to, which is usually the length of the race. There are significant advantages to having increased performance (winning), and not many for increased mtbf. It's perfectly possible to tune and engine to the load you describe *and* achieve high reliability. -- Champ What doesn't kill you only makes you stronger ZX10R | GPz750turbo | GSX-R600 racer (for sale) | ZX10R racer (broken) neal at champ dot org dot uk |
#15
|
|||
|
|||
Hyabusa flat 8
Using the patented Mavis Beacon "Hunt&Peck" Technique, platypus
typed Wicked Uncle Nigel wrote: Using the patented Mavis Beacon "Hunt&Peck" Technique, "TOG@Toil" typed On 6 Mar, 11:03, bod43 wrote: On 5 Mar, 21:57, "Morgans" wrote: snip interesting stuff Maybe someone on uk.rec.motorcycles might have an idea as to the expected life span of a hyabusa engine when operated in a constant load regime, say at 130bhp. You'd need to boost the low and midrange torque to swing a prop, as props rotate relatively slowly, don't they? I think a 'Busa engine would last forever is detuned to 130bhp. Depends on the prop, but I would think that gearing down would be the way to go. The thing that everyone seems to forget when promoting automotive engines for aircraft is that most piston aero engines have a very hard life. Take-off and climb is full power or very nearly, then they throttle back to cruise at 75% or thereabouts. The only roadgoing vehicles that approach that sort of use are in motorsports, and how long do they last? Full *rated* power. If the Bus engine were to be de-rated to 130BHP it'd barely be breaking sweat in the climb. Of course, you could have one of those cool "War Emergency Power" seals on the throttle to enable you to get more power when your microlight has a pair of marauding Bf109s on its tail... -- Wicked Uncle Nigel - "He's hopeless, but he's honest" It's important is that last ell. |
#16
|
|||
|
|||
Hyabusa flat 8
Wicked Uncle Nigel wrote:
You'd need to boost the low and midrange torque to swing a prop, as props rotate relatively slowly, don't they? I think a 'Busa engine would last forever is detuned to 130bhp. Depends on the prop, but I would think that gearing down would be the way to go. If you're forced to use a higher-revving engine, yes- but gearboxes or belts and cogs introduce problems of their own, which is why a relatively large displacement slow-revving engine (which doesn't need four valves/cylinder, multiple chain drive cams with cam chain tensioners, etc.) makes a lot of sense for aircraft. |
#17
|
|||
|
|||
Hyabusa flat 8
On 6 Mar, 14:15, Mark Olson wrote:
Wicked Uncle Nigel wrote: You'd need to boost the low and midrange torque to swing a prop, as props rotate relatively slowly, don't they? I think a 'Busa engine would last forever is detuned to 130bhp. Depends on the prop, but I would think that gearing down would be the way to go. If you're forced to use a higher-revving engine, yes- but gearboxes or belts and cogs introduce problems of their own, which is why a relatively large displacement slow-revving engine (which doesn't need four valves/cylinder, multiple chain drive cams with cam chain tensioners, etc.) makes a lot of sense for aircraft. Which was what I was thinking. I mean, what was max revs for a Merlin? Googles Hm. About 3000rpm. Just off tickover for a 'Busa. |
#18
|
|||
|
|||
Hyabusa flat 8
"bod43" wrote in message ... I have the idea that mechanical failure of the original 4 cyl engines (or any high performance japanese bike engine) is pretty much unheard of but I am not at all sure. It matters little, because now you are making a whole new engine for a totally different application, with no track record and the distinct possibility of new and exciting failure modes. Further, the same can be said about the reiliability for most any automotive engine in its intended application, but the track record of automotive aero conversions is spotty at best. Just thinking outside the box... Since the proposed Hyabusa Flat 8 engine will need a PSRU anyhow; how about two Hyabusa engines put together into a twin-pack? The result would likely weigh a tad more than a simple flat 8, but now you have two known engines combined with twin-engine redundancy. Vaughn |
#19
|
|||
|
|||
Hyabusa flat 8
On Mar 6, 8:38*am, "vaughn" wrote:
"bod43" wrote in message ... I have the idea that mechanical failure of the original 4 cyl engines (or any high performance japanese bike engine) is pretty much unheard of but I am not at all sure. * *It matters little, because now you are making a whole new engine for a totally different application, with no track record and the distinct possibility of new and exciting failure modes. *Further, the same can be said about the reiliability for most any automotive engine in its intended application, but the track record of automotive aero conversions is spotty at best. Just thinking outside the box... *Since the proposed Hyabusa Flat 8 engine will need a PSRU anyhow; how about two Hyabusa engines put together into a twin-pack? *The result would likely weigh a tad more than a simple flat 8, but now you have two known engines combined with twin-engine redundancy. Vaughn There is little difference between the existing V8 Hyabusa and a flat 8 in terms of bottom end design. The V8 has proved bulletproof @400HP. Pretty much everything learned with the V8 Hyabusa conversion applies to a flat 8. Of course it would need to be geared - torque peak is near 8000 RPM. However, there is a weight trade off. These little screamers, which are more like turbines than tractors, can use a light crank because they use a whole lot of tiny power pulses instead of a few humongous ones to produce power. The Hyabusa is on the extreme opposite end of the power/RPM spectrum from a Lycoming. Weight savings in the crank can be shifted to the PSRU which would be a planetary gearset with maybe 5 planet gears for lots of tooth engagement and strength. The gear ratio would need to be 4 or 5:1 so spur gears or cog belts aren't the best choice since the small gear or cog would be small with too few teeth engaged. A planetary allows large ratios with lots of tooth engagement for strength. Keep in mind how the motorcycle works. The bike has a 6-speed gearbox whereas the airplane engine would have only one. The standard sport bike shift technique, approved by the factory, is to apply a large force to the shift lever and then tap the clutch lever when the rider wants to shift. This results in an instant shift with horrific transient loads suffered by the crank and drive train. An aircraft powerplant would never see this abuse. Why is a flat 8 better than a V8? Mainly a higher thrust line for prop clearance and better ballance. To do that with a V8, it would have to be inverted. |
Thread Tools | |
Display Modes | |
|
|
Similar Threads | ||||
Thread | Thread Starter | Forum | Replies | Last Post |
There I was, flat on my back... | Kyle Boatright | Home Built | 5 | August 16th 07 05:34 AM |
Flat tire | Viperdoc[_4_] | Piloting | 11 | June 4th 07 02:57 PM |
Flat Tires? | Jay Honeck | Owning | 40 | August 31st 05 01:59 AM |
Wrinkly flat panels | [email protected] | Home Built | 27 | March 6th 04 02:12 PM |
Flat Spin | JJ Sinclair | Soaring | 34 | February 10th 04 05:57 PM |