I have fitted my AR coated screen but it hasn't had the expected effect. When viewed in direct sunlight (doesn't happen that often here in England!!) the sunlight appears to be reflected by the glass VFD itself. This makes it difficult to see what's actually being displayed by the Empeg. Does anyone else have this problem? I'm wondering if a polarising filter behind the coloured screen would help. Any ideas anyone?
Oh... and last night my knob started slipping (fnar fnar) - I'll have to get on to Empeg to send me out a new one.
All in all though, a great product :-)

beaker
12 gig blue

My AR screen arrived last week and it works perfectly. Yes in direct sunlight it is washed out, but try to show me any kind of display screen that isn't.

Perhaps you got an old non AR screen?

John

Thanks for your reply.
No, it's definitely an AR screen, it's got a slightly rough surface to it which 'softens' the display. I had Empeg send one out to me. The only type of display which doesn't really suffer is LCD but I they're not really suitable for the fast moving graphics (discussed to death elsewhere on this bbs).

beaker
12 gig blue

I received a blue one and it really doesn't help any. I may end up putting the old one back on because I think it looks better in most conditions.

-Rob
-----
12GB MK2 Blue 090000736 (6166 in the queue)

In direct sunlight (i.e., the sun is shining directly upon the VFD display), I can only barely read the text. If yours is completely washed out (if you can't see any text at all), then your VFD might not be operating at its full brightness. If you can barely see the text in direct sunlight, then that's normal: It's the best they can do with the VFD and an AR panel.

___________
Tony Fabris

In normal ambient daylight here in England (alright so it's dark most of the time) the display is perfectly bright to see easily. However when the sun is low (which it is most of the time at the moment) and it is shining directly into the Empeg display the flourescent elements inside the VFD appear to reflect this light back out and therefore reduce their contrast with the elements which are emmiting light.
As light which is reflected is quite often polarised (but not always) I thought that this might be a cure. Anyone got any ideas, experience or comments on this idea?
It's not a great problem at the moment as the sun isn't out for long enough. I'm thinking ahead to the summer when the sun will be out for more than 10 seconds (ha ha!!) in any 24 hr period.

beaker
12 gig blue

Same here (green). Works better for me with the original non AR panel so I put this one back on. Tx J.

What are you going to do with your blue AR screen?
Would you maybe give it away? I'd be interested in having a different color...

TeeMcBee
Got my Mk2! # 080000143

What beaker said above about the elements of the VFD shining back is right on the mark. In direct sunlight, the non-lit elements shine just as bright as the lit elements. It's because the elements themselves are too reflective, reflecting sunlight back as if the element was lit. The best way to solve this problem is to find a VFD that is not reflective. Either that, or find a display screen that can distinquish between reflected light and light emitted by lit elements. I'm not surprised the AR screen still does not work that well in direct sunlight.

Hrm.. I got my red AR faceplate in.. it looks signifigantly better.. tho almost all displays that are backlit like the empeg loose something in sunlight.. the empeg looks better than most laptops in sunlight. :)

12gig red mk2 -- 080000125

I agree. My green display is better in direct sunlight than before. It's still not great, but that's hardly empeg's fault. I have a navigation system above the empeg, it's even indented a bit, and it suffers wash-out in direct sunlight. Good thing I don't have to worry about it all that much in my nice big van, though

DiGNAN

I agree the display itself would have to be AR coated to work effectively but that would it be very difficult at best to coat the VFD with a one-way mirror surface. While the AR coated screens don't really work as intended I like the effect they have from the dimpled surface it seems to give a blurred delayed look to the visuals.

#695 Mk2 BLUE 12Gig

Ask and I may tell you

...should be easy enough to test. You should be able to buy polarizing film, and just cut it to match the faceplate. Natural static should keep the film stuck to the faceplate, although if the VFD is warm, I don't know it the film will tolerate that.

Let us all know if you try that out.

- - - - - - - - - - - - - - - - - --
MK2 #141, green, 12GB

Yeah, I've looked for some kind of polarising film but haven't had much luck so far. Even though I did suggest this as a possible cure in the first place I'm not very confident about it actually working. I'm also not sure whether it would darken the actual display too much either. Still, I'd like to try it all the same. I'll let you all know if I find any polarising film and whether it helps at all.

beaker
12 gig blue

Silly suggestion on the direct sunlight bit, have you looked at polarizing film or tint for the offending windows? I know I've seen good & bad jobs of tint, but thought I'd throw it out there.

My take is that I don't really expect any display to work well in direct sunlight. I think the AR screen does what it's supposed to though.

-Zeke

just say you weren't paying much attention...

Interesting thought. Trouble is I'm not a "tinted windows" kinda guy though. Most of the cars around here with tinted windows are either driven by teenage boy racers (no offence to teenage boy racers) or drug dealers.
Thanx for your input anyway.

beaker
12 gig blue

Yeah. I know what you mean. I don't have them myself but I thought I toss that out there. Skinning cats & all.
I have dreams of an active LCD windshield that uses cameras to track the driver's eyes & black out oncoming headlights. We just need to build one & ditch the eyetracking for empeg tracking. Anyone? ;-)
Maybe by the time I'm 90. I'd probably put it into one of these: http://www.moller.com/skycar/m400/.

-Zeke

just say you weren't paying much attention...

I should say it would be difficult for the home user in general to coat the VFD per Empeg. But maybe Empeg could do it to the forthcoming units.
I'd hate to have the film melt to the VFD.

#695 Mk2 BLUE 12Gig

Ask and I may tell you

I also received my AR-coated screen (blue).
In the installation instructions there was notice of removing some protective skin off the screen before installing.
I've peeled for a quarter of an hour, but I couldn't get anything off. I just installed it...
Is there some protection-skin on the AR screens?

Frank van Gestel

I have dreams of an active LCD windshield that uses cameras to track the driver's eyes & black out oncoming headlights.

I thought I was the only one who had that idea. (Mine included blocking the sun, too.)

___________
Tony Fabris

Surely you don't want to completely block oncoming headlights? . They are partly to let you know about the oncoming car that's immediately behind the aforementioned oncoming headlights.

Otherwise, you could just put masking tape over your eyes, and you'd never have this problem again .


Roger - not necessarily speaking for empeg

No, the idea would be to use LCD to darken the excessive blinding glare while still allowing you to see what's behind the glare. It would actually improve your ability to see the oncoming cars because you wouldn't have to avert your eyes.

The only way it would work is if the LCD were dynamic and could localize to small regions of the window, and track depending on the driver's head position.

It's all a pipe dream, of course, such a system would be so prohibitively expensive as to only be available on fighter jets or something.

___________
Tony Fabris

Err, no, not on the current batch. Do the installation instructions say for Mk.1 or Mk.2? If Mk.1 then someone made a packing mistake, if Mk.2 I need to update the text!

Rob

I thought I was the only one who had that idea. (Mine included blocking the sun, too.)

Me too.

Steve Bates

We can dream though. At least until summer comes and I don't have to commute in total darkness.

-Z

just say you weren't paying much attention...

I'd probably put it into one of these: http://www.moller.com/skycar/m400/.

I don't want to rain on anybody's parade here, but just like that 78 million dollar personal submarine discussed in another thread, there are a lot of numbers that don't add up here.

1) Gross weight 2400 pounds; 900 miles @ 15 MPG = 60 gallons of fuel at 6.6 lbs per gallon = about 400 lbs for fuel. Four passengers at 185 lbs each = 740 lbs. Add another 60 lbs for oil, coolant, etc., and you are up to 1200 lbs useful load, leaving 1200 lbs for the empty aircraft. OK, no arguments there, just laying the groundwork.

2) Eight 120 horsepower engines in a vehicle that weighs (empty) 1200 pounds. Even assuming that the airframe were made of exotic unobtainium alloys and weighed only 800 pounds (impossible for a four-passenger vehicle) that leaves 50 pounds for each 120 HP engine, which is about 1/3 the weight per horsepower of any internal combustion engine I am aware of.

3) 960 horsepower... it would probably need that to generate the thrust to keep it in the air. Since the aiframe lacks wings or other lifting surfaces, the lift/drag ratio is going to be ridiculous. I don't believe that 960 HP would be enough to both provide lift and provide propulsion to a maximum speed of 390 MPH.

4) A general rule of thumb for fuel consumption in an internal combustion engine lightweight enough to be used in an aircraft is one-half pound of fuel per horsepower hour. Figure 75% of max power at the claimed cruise speed of 350 MPH, that would be 720 HP, which would require 360 lbs of fuel per hour or 54 gallons of fuel per hour, which works out to something less than 6.5 miles per gallon, about 40% of the mileage they are claiming. Their FAQ page strongly implies that the engines are Wankel-type rotary engines. These engines have never been known for fuel economy.

5) Operating ceiling of 30,000 feet. By the time they reach that altitude, they might have 400 horsepower left (internal combustion engines don't work well at Mt. Everest altitudes) and remember, there are no lifting surfaces on this little jewel, so it's all thrust. Some really good mountain rescue helicopters (priced in the multi-million dollar range) with big honkin' twin turbojet engines putting out several thousand shaft horsepower at sea level (and without as large a power penalty at altitude as an internal combustion engine) can make it up to about 23,000 feet, and that's with several hundred square feet of lifting surface (rotors) spinning at 1,000 RPM or so.

6) Noise level: 65 decibels at 500 feet. Yeah, right. With eight engines cranking out 960 horsepower and four eight-bladed ducted fans screaming for all they're worth... 65 decibels is the noise level you would expect to hear in a good luxury car at 60 miles per hour. You wouldn't even need to crank your empeg into overdrive to overcome that much noise.

7) Maximum rate of climb 7800 feet per minute. That's the equivalent of 90 miles per hour straight up. A good twin-engine turboprop aircraft with double the power plus the considerable advantage of generating lift by means of wings (far more efficient than brute thrust) might be able to attain a third of that rate per climb.

8) 900 mile range. I don't see how. With no aerodynamic lift, the fuel efficiency (i.e., miles per gallon) could only improve as speed went up (at hover, you are getting zero miles per gallon) but somewhere along the line the fuel consumption curve will butt heads with the wind drag curve and that's likely to be in the neighborhood of 100 MPH. (just guessing here, but to push any 4-passenger vehicle beyond 100 MPH starts requiring pretty serious power) So you need 9 hours of fuel. 60 gallon capacity, you could burn no more than 6.6 gallons per hour. Well, you can make about 90 horsepower with 6.6 gallons of fuel per hour. That thing is not going to be airborne on 90 horsepower (remember -- no lifting surfaces) much less fly 900 miles.

9) Enough. You get my point? I have seen a lot of these "miracle aircraft" come and go over the decades, and the main thing they have in common is for one reason or another they never quite come into existance.

So, I've heartlessly trashed submarines and aircars... what's next? How about ornithopters, or maybe lighter-than-air vehicles?

tanstaafl.


"There Ain't No Such Thing As A Free Lunch"

MK2 that is...

Frank van Gestel

wasn't there a Simpsons episode on this?

____________________
Murray 06000047

exotic unobtainium alloys

I laughed out loud when I read that.

there are a lot of numbers that don't add up here.

I read through your numbers, and I see your point. I was skeptical of the aircar, too, when I first read about it, but I didn't have any numbers to base my skepticism on. I wonder if anyone has pointed out this particular Emporer's nakedness to its investors?

One thing, though:

Since the aiframe lacks wings or other lifting surfaces, the lift/drag ratio is going to be ridiculous.

I was under the impression that it would be a sort of a lifting-body design. That at full forward thrust, there would be a decent amount of lift generated by the whole thing. I'm no aerospace engineer, though, so I don't know.

--Tony smacks his forehead--

D'oh! I've just encouraged Doug's number-crunching again. Bad! Bad!

___________
Tony Fabris

that leaves 50 pounds for each 120 HP engine, which is about 1/3 the weight per horsepower of any internal combustion engine I am aware of

Then you haven't seen the twin rotor Norton rotary engines they are using. They powered motorbikes for quite a while, with an overall weight of 35 lbs for the race engines. I can't remember the specific BHP figures, but they were generating the same shaft outputs (and higher) than 1,000 cc bikes, whilst being officially rated as 600cc capacity. A damn good engine design.

that the engines are Wankel-type rotary engines. These engines have never been known for fuel economy

They are Norton rotaries. Norton specifically marketed the engine for lightweight, airborne applications, including drone engines and unmanned surveilance aircraft. They have excellent fuel economy and low weight - the road bikes they powered regularly returned around 34-40 mpg even when you thrashed the knackers off them. They only really got thirsty at low RPM, and the race bikes eventually sorted this out by good engine management and new fuelling strategies.

65 decibels at 500 feet. Yeah, right. With eight engines cranking out 960 horsepower and four eight-bladed ducted fans screaming for all they're worth...

Don't forget ducted fans are inherently quieter outside the duct - I think they are referring to the dBA (perceived loudness) levels on the ground.

So, I've heartlessly trashed submarines and aircars... what's next?

...and a good laugh was enjoyed by all. For someone who professes to be "no engineer", you do a pretty damn good job of analysis... Nice one, Doug!

PS. Oh, they may have one other minor problem that you don't mention here - Norton Motors (1974) Ltd. went belly up due to fraudulent financial dealing and bad marketing about 6 years ago - they don't make the engines any more and didn't license their manufacture to anyone....

PPS How did we get to be talking about rotary engines when we started out about AR screens?


One of the few remaining Mk1 owners... #00015

Jaguar have been experimenting with this one for about the last three years, combining it with an IR night vision system and HUP display.

Don't count on it being in the shops any time soon - you know what Jaguar's record for getting product to market before the Ford takeover was like....

One of the few remaining Mk1 owners... #00015

I dunno. I never thought a simple question like mine about AR screens would have transmogrified into it's current discussionary state. Anyway while we're on the subject of Norton rotaries didn't the race bikes prove to be quite successful? They also used the engine in some police bikes (called the "Interpol II" I seem to recollect) and in a very expensive road bike called the F1. They should have marketed the bike at a lower price so that they were competitive with the Japs, like Triumph have done so successfully. They might have survived. This might be oversimplifying their problems but it's a nice thought.

beaker
12 gig blue

In reply to:

---

4) A general rule of thumb for fuel consumption in an internal combustion engine lightweight enough to be used in an aircraft is one-half pound of fuel per horsepower hour. Figure 75% of max power at the claimed cruise speed of 350 MPH, that would
be 720 HP, which would require 360 lbs of fuel per hour or 54 gallons of fuel per hour, which works out to something less than 6.5 miles per gallon, about 40% of the mileage they are claiming. Their FAQ page strongly implies that the engines are
Wankel-type rotary engines. These engines have never been known for fuel economy.

---

look here for a reply by Dr Moller himself
for more stuff look here

Frank van Gestel

didn't the race bikes prove to be quite successful?

Yes, they raced a number of seasons with relatively little improvement between seasons; they were basically road bike engines with special carburation and race pipes. They stood up to the competition extremely well and lasted a long time under hard race conditions. I managed to sit on one at Donington years ago and was astonished at the size of the bikes; they were little miniature gems.

some police bikes (called the "Interpol II" I seem to recollect) and in a very expensive road bike called the F1

There were a number of road bikes, both air and liquid cooled. The aircooled ones were first trialled by Durham police, and I got to wheelie one (yup, a full-faired Jam sandwich). I managed this 'cos my rugby club team coach was a RT Sergeant and he "loaned" me it for 10 minutes. When I got out of sight I whacked open the throttle and the front wheel just shot into the air. Marvelous - but not if you're a traffic cop. They didn't buy any; one of the delights of these early bikes was that when you went onto full left lock, the tension in the harness that ran under the tank caused the connector to pull off the ignition switch, which cut out the engine....

Virtually the same bike was produced in a small batch for public sale before they began production of the liquid cooled ones. There were again fully faired police versions and road versions; the Army, RAC and AA bought quite a few. Then there were the race reps - the second one was announced as the F1, which was basically their last gasp; the company tried to get the manufacturer of the race framed version to produce them in bulk, but the company collapsed.

To be honest, it wasn't the kit that was the problem - it was the same old warhorse, bad management. They didn't re-invest in the right machine tools and skimped on production, so the bikes just gradually got worse and worse. Finally, the management team were caught in some dodgy share dealing and the whole thing fell apart. Although there were rumours that the (then still in development) new Triumph company would buy them out, it never happened.

I'd love to know who owns the manufacturing rights to the engine, as it was the real heart of the bike; I have never forgotton just how tiny the bikes were (about the size of a 400cc), the massive torque of the engine, and the almost vibrationless operation; there was no red line on the tacho, and if you opened the throttle it was like there was an electric motor there instead of an IC engine. What a wonderful, wonderful machine.

One of the few remaining Mk1 owners... #00015

Yes, but does it have a DIN slot?

-Z

just say you weren't paying much attention...

Thing is they have built the subs already, not a conception so I guess they work.

#695 Mk2 BLUE 12Gig

Ask and I may tell you

Thing is they have built the subs already, not a conception so I guess they work.

I dunno about that. The site advertising those particular subs (the giant luxury-yacht size personal subs we discussed earlier in another thread) had only paintings, not photographs.

Yeah, they've made little tiny personal submarines, but Doug wasn't talking about those when he made his statement.

___________
Tony Fabris

In reply to:

---

I'd love to know who owns the manufacturing rights to the engine...

---

I believe there were two separate parties involved in buying Norton's copyrights. One bought the Norton name and another bought up the rights to manufacture the engines (I presume this would include the rotary unit). I think one of them was Canadian but I'm not sure which one it was. I know there have been some arguments between the two of them as to who has the right to do what.
I could of course be talking complete rubbish, but that's what I seem to remember happened.

Wheelieing a police bike eh!! you naughty boy . Good fun though I must say. I'm not a wheelie merchant myself but it sure does feel good when that front tyre (inadvertantly)leaves the Tarmac . I've got a Yamaha FZR1000 Genesis which is quite well behaved unless the tank is nearly empty or you've got a pillion on board (hehe).

beaker
12 gig blue

I was under the impression that it would be a sort of a lifting-body design.

Looking at the admittedly beautiful and curvaceous shape of that aircar, I see very little in it that would generate any lift. To get lift, you need some sort of airfoil shape. This is always more efficient (in terms of drag) than powering a flat surface at an angle of attack sufficient to provide enough lift to remain airborne. The term lift/drag ratio refers to how much drag you incur for x amount of lift. Generating lift causes induced drag that, while not really the same as pure aerodynamic drag, still requires energy to overcome. The more efficient a shape that a wing (or lifting body or, for that matter, a brick) has, the less power it takes to generate the lift required to remain airborne. I see lots of drag compared to the amount of lift in the Aircar's design.

tanstaafl.

"There Ain't No Such Thing As A Free Lunch"

look here for a reply by Dr Moller himself

Well, somebody else asked pretty much the same questions I asked, with pretty much the same logic. I did not find Dr. Moller's responses to be all that informative.

Unless that Aircar shape is somehow generating enormously more aerodynamic lift than it would appear in the picture, I remain skeptical. His claim that "...At 25,000 ft. the thrust required for optimum cruise speed is only 66 lbs. from each nacelle..." would imply that he is generating more than 2100 lbs of aerodynamic lift in some very thin air.

But, who am I to argue? Dr. Moller is an aeronautical engineer. I'm a guy with a (non-current) pilots license looking at a picture of an airplane. I have to think that, unless this is a total fake designed only to defraud investors (and please note I am not saying that is the case), he certainly knows more about aircraft design than I ever will.

tanstaafl.



"There Ain't No Such Thing As A Free Lunch"

with an overall weight of 35 lbs for the race engines. I can't remember the specific BHP figures, but they were generating the same shaft outputs (and higher) than 1,000 cc bikes

OK, that would work out to be about 2.5 HP per pound, about what is being claimed for the Aircar engines. But that is maximum, peak power, and even at a 70--75% cruise setting, would not be sustainable for uninterrupted hours at a time. It's been a while since I was really up on rotary (Wankel-type) engines... but I seem to recall problems with apex seal failures under heavy sustained loads as are typically encountered in an aircraft environment.

Norton specifically marketed the engine for lightweight, airborne applications, including drone engines and unmanned surveilance aircraft.

Yes, but not at anything approaching 120 HP rating, I suspect. A typical aircraft engine (Lycoming, Continental, etc.) puts out power in the neighborhood of about 1/2 horsepower per cubic inch displacement. Compare that to something like a Honda S2000 engine which puts out something in the neighborhood of two horsepower per cubic inch -- four times the specific power output. So why are regular aircraft engines so "inefficient"? Because they have to operate at 75-80% of their maximum output for hours on end, and 100% of maximum during takeoff. They have to keep the stresses down to keep the longevity up (and even so, they must be overhauled after each 1000 hours of use) which means big cubic inches, little horsepower. Small, highly efficient engines are not normally suitable for light aircraft use.

They have excellent fuel economy and low weight - the road bikes they powered regularly returned around 34-40 mpg

[Sarcasm]Whoopee! A 350 pound motorcycle, operating at (on average, probably) 1/3 to 1/2 maximum power output, on the ground (no need to waste power generating lift) at speeds averaging less than 1/4 the speed claimed by the Aircar and with about 1/5 the gross weight and maybe 1/10 the frontal area can get more than twice the claimed mileage of the aircar. I'm not impressed.[/Sarcasm] I'll bet that on a measured economy run averaging, say, 80 miles per hour, that a Honda Insight with two passengers and luggage, would do better than that motorcycle. (The Honda would pull down 45-50 MPG at that speed, I belive...)

I think they are referring to the dBA (perceived loudness) levels on the ground.

Absolutely -- from a distance of 500 feet. That's not very far away, and those fans are going to make a good bit of noise, ducted or not, as the blade tips are approaching supersonic (they are small diameter, they have to turn them fast Let's see, they look to be a bit under three feet in diameter, call them 2.9 feet across. That's 9.1 feet around, they're turning them at 7200 RPM at takeoff, that's 65,520 feet per minute. Speed of sound is, what, 1100 feet per second, 66,000 feet per minute, that means those blade tips are turning at mach .993. Yep, that's pretty close to supersonic) and pretty damn noisy. Then, you have eight unmuffled (I assume unmuffled, otherwise you give up power) rotary engines running at maximum output. I'm sure you've heard an unmuffled rotary under those conditions -- hell, if they fired it up in Dover you'd hear it clear across the Channel in France. Now imagine eight of them at once... 65 decibels at 500 feet? No way. A typical office environment (with people conversing, air handlers blowing air around, etc.) is louder than 65 decibels.

PPS How did we get to be talking about rotary engines when we started out about AR screens?

Y'know, that's what I love about this bbs. It sometimes goes off on the most fascinating tangents!

tanstaafl.











"There Ain't No Such Thing As A Free Lunch"

Hmmmm..... That's interesting, because it means there is still a chance that someone's making spare parts, or that the engine could still be manufactured. I am not too upset about the Norton name (I should be). Still, now I can go out and research it a bit. Incidentally, I picked up a recent book covering the entire history of the Norton rotaries, so if anyone's interested, post here and I shall post the title and publisher details. It's an excellent little book, and very interesting.

As regards the wheelie... Well, it's a fair cop, guv. I confess it was accidental - I was just not expecting it. At the time I was riding a Guzzi Le Mans which had all it's weight forward - absolutely no way could you get the front end off the ground (well, not strictly true - I did see someone stand on the seat of a T3 with cow-horn bars yank the bike off the ground, but he was really trying ) - I opened the throttle on the rotary expecting both the same weight bias, and the same throttle spring resistance (MISTAKE!!) and found both to be rather lighter than expected. Ooops....


One of the few remaining Mk1 owners... #00015

I seem to recall problems with apex seal failures under heavy sustained loads as are typically encountered in an aircraft environment

Loaded seal failures were very much a common problem with all early rotaries; Norton worked long and hard on sorting this out. They were absolutely focussed on this as their major selling point was to be engine longevity and reliability. One of the early air cooled prototypes ran continuously for 24/7 for over four years without stopping. During this run, the engineers didn't bother opening it, but stopped it occasionally and stuck in an opthalmoscope to have a look at the crank and seals. No wear was observed - when the company stopped the trial and pulled it down, they were pretty surprised to find that they had no need to replace anything and it went back together after the crank was crack tested. For a while the engine was in the company museum, with just the measured number of crank rotations on display in front of it.

Also, don't forget we're not talking about the rotaries of the late 60's/early 70's (DKW, NSU, Mazda) - this engine design began life around 1965 in a seperate research group that survived the NVT collapse in '72. They were developing various forms of the engine for almost 20 years. They hold(held?) many patents on the engine, and a significant amount of their work was cross licensed by Nissan in the 80's to improve their own car engines (Norton and Nissan were pretty much alone in persisting with the design, with good results).

Small, highly efficient engines are not normally suitable for light aircraft use

...Except when the plane is going to get a SAM 7 up the pipe, in which case so long as it reached the target, it wouldn't matter so much

No, I know what you mean about loading and stress levels; but don't forget, the engine is radically different from reciprocating piston engines - the big cubes, low power argument is not directly applicable here. The crank was a short, single cast piece, and the rotors span epicyclically around it to reduce crank flex. The engine was a narrow sandwich of a pair of combustion chamber cavities, and so the crank was absolutely rigid. The crank bearings were just great big plain bearings, even on the race bikes! In fact, the rigidity of the engine on the race bikes turned out to be a problem - they used it as a stressed member in the frame and the resulting frame design was remarkably minimal. When they took it out on the track, the frame had such little flex, that the tyres could not cope with the cornering stress the bike could deliver. The most frequent observation of the race press at the time was "yet another tank slapper" as the tyres rapidly gave up the ghost half way through the race. One of the riders was rather a big bloke (Trevor Nation) and observed that the subframe they bolted onto the back of the frame to carry the seat used to bend about an inch or so when cornering, which moved the centre of gravity and destabilised the bike as the rider moved out due to centripetal force....

As I described, the long term engine ran for four years without a service. I have no idea what engine speed it ran at, or what percentage of output power, but it was definitely reliable.

those fans are going to make a good bit of noise, ducted or not, as the blade tips are approaching supersonic

Although I agree with this argument, you are assuming the use of conventional propellers inside the ducts. NASA researched a new form of multi-blade prop which was designed to prevent a leading edge causing the shock wave associated with close-to-mach speeds. They are effectively conical spirals with odd numbers of blades, designed to operate in ducts - so before you ask "why wasn't this built into fighter jet airfoils?" it has to be ducted to work successfully; or "why not in the guts of jet engine compressor structures?" it is not suited to multi-blade compressor application (for various reasons). When they got it working (I think it was the JPL did the work), they were proposing turbo-prop engined (eh? Lo-tech!) delta wing aircraft with ducted fan engines that could hit mach 1. Quite an interesting development; haven't seen a damn thing about it since I read the article - but the fan designs (if that is indeed what the Moller is using) were incredibly quiet and fuel efficient. I'll see if I can turn up the article (it was in OMNI years ago, and I might have kept it), but don't hold your breath!








One of the few remaining Mk1 owners... #00015

Eerrr.... As the observant of you may have noted, I must have been drinking stronger red than I thought; when I said Nissan Motors, I did of course really mean Mazda, who produced the rather excellent RX-7 Sports. Sorry about that...

For those of you really interested in one of the very last ones, there's a pre-registered one that I know of with only delivery mileage at a nice price. Drop me a line and I'll pass on the details. They also have a lot of used, low-mileage Miatas...

One of the few remaining Mk1 owners... #00015

For those interested in the rotary engine, I believe Mazda is going to be coming back out with a rotary based vehicle within 1-2 years. I heard this at a meeting I was at with Mazda, but don't remember any more details.

-Zeke

just say you weren't paying much attention...

I seem to remember that they had a Rotory engine running on Hydrogen in some MX-5 demonstrator.
Apparently a Rotory engine is good with hydrogen, due to the intake and combustion taking place in different areas it has less problems with heat.

I might have imagined it though... =)

Jazz
(List 112, Mk2 12 gig #40. Mk1 4 gig #30. Mk3 1.6 16v)

Unless that Aircar shape is somehow generating enormously more aerodynamic lift than it would appear in the picture, I remain skeptical.

See here or here (which the previous links to).



Roger - not necessarily speaking for empeg

I missed this thread earlier. (Hey, I'm not just slow on the uptake)

I can't remember the specific BHP figures, but they were generating the same shaft outputs (and higher) than 1,000 cc bikes, whilst being officially rated as 600cc capacity. A damn good engine design.

The engine was, from memory, 588cc in swept volume and produced approximately 115BHP as standard. It was possible to tweak them pretty severely, to well over 150+BHP. I lusted after one of these things for years during my light hovercraft days, but never managed to get one.

The motorcycle racing industry was somewhat divided on their liking for the things, and at one point an attempt was made to classify them as a 1176cc engine, since wankel designs have the rotor turn twice during a complete power cycle, because some people wanted to get them out of the sub 1-litre category due to the competition.

An interesting fact: in the early 90s sometime, when they were actually making the things, they had sold something like 8 time as many engines as bikes with engines, mostly to people with microlights, etc. There are even some light aircraft still flying with the things in. The cost of the engine was around £3000 a unit, too high for me.

Patrick.




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