Personal tilt-rotor

[Henning]

I'm trying to see where he said 90 Kw per side, but in any case, 200 Kw divided by 746 watts per horsepower is 268 hp. ANd that's ignoring efficiency losses. If it has a 100 hp engine it won't go far. And any 100 hp engine that produces that power at 2-4 GPH is a marvellous engine that we need to drive propellers with. Normally, a 100 HP engine is going to burn about .4 lb/hp/hr, at least, and that works out to 40 lb/hr which is 6.7 GPH, at best.

I'm 55 years old and spent many years reading PopSci and Popular Mechanix and so forth, and as I got older and read repeatedly of fantastic new machines that never, ever made it to market, I got a little cynical. I've seen dozens of new engine designs, helicopters, airplanes, VTOL machines and the like, yet we're still using the same old piston engine in our cars that we were using the the '50s, just with fancier fuel and spark delivery systems. We're still flying airplanes designed in the '50s (and earlier, though the composites made a big difference) and there isn't a helicopter in every driveway. And Mr. Moller has been fleecing the innocent for decades now and continues to do so.

Forgive me for wanting to see a flying prototype before I believe anything more I see in the "science" magazines.

Dan

120hp = 90kw Generator output half of full V/TOL requirement with batteries making up the other half of the power for the liftoff and translation. I was wondering about the cabling as well for loss and weight calculations. I think they are going to grow fat by a bit.

 

[Dave Krall CFII]

I'm trying to see where he said 90 Kw per side, but in any case, 200 Kw divided by 746 watts per horsepower is 268 hp. ANd that's ignoring efficiency losses. If it has a 100 hp engine it won't go far. And any 100 hp engine that produces that power at 2-4 GPH is a marvellous engine that we need to drive propellers with. Normally, a 100 HP engine is going to burn about .4 lb/hp/hr, at least, and that works out to 40 lb/hr which is 6.7 GPH, at best.

I'm 55 years old and spent many years reading PopSci and Popular Mechanix and so forth, and as I got older and read repeatedly of fantastic new machines that never, ever made it to market, I got a little cynical. I've seen dozens of new engine designs, helicopters, airplanes, VTOL machines and the like, yet we're still using the same old piston engine in our cars that we were using the the '50s, just with fancier fuel and spark delivery systems. We're still flying airplanes designed in the '50s (and earlier, though the composites made a big difference) and there isn't a helicopter in every driveway. And Mr. Moller has been fleecing the innocent for decades now and continues to do so.

Forgive me for wanting to see a flying prototype before I believe anything more I see in the "science" magazines.

Dan

The Geo-Suzuki redrive conversions report 3-4 gph for 100+ hp. They of course have brain boxes, fuel injection, redrives, and some like ours are turbo/intercooled. Our static runup tests so far although crude, indicate fuel consumption of about 4 gph (89 octane) @ full power (120-150 hp) and we should have better figures soon while airborne for awhile.

 

[Henning]

The Geo-Suzuki redrive conversions report 3-4 gph for 100+ hp. They of course have brain boxes, fuel injection, redrives, and some like ours are turbo/intercooled. Our static runup tests so far although crude, indicate fuel consumption of about 4 gph (89 octane) @ full power (120-150 hp) and we should have better figures soon while airborne for awhile.

You ought to do a dyno run on that engine so you have a real baseline to work off of rather than guesstamating.

 

[docmirror]

The Geo-Suzuki redrive conversions report 3-4 gph for 100+ hp. They of course have brain boxes, fuel injection, redrives, and some like ours are turbo/intercooled. Our static runup tests so far although crude, indicate fuel consumption of about 4 gph (89 octane) @ full power (120-150 hp) and we should have better figures soon while airborne for awhile.

Ok, this I would need to verify independently. The best I've ever seen is a high Q stratified charge four-stroke diesel type dry sump engine that did about 250 g/Kw/hr. If I've done the conversions right, (250g = .44Lb & 1Kw = 1.34 HP, then .44 /1.34 = .328 BSFC) that gives .33 BSFC. Which is pretty remarkable on a hydrocarbon based fuel.

If you're doing 4GPH to get 100HP that sounds like a BSFC of .24 and that doesn't sound right to me. (4GPH * 6LbGal /100HP = .24)

There may be some errors in your calorimetry somewhere. I think a thermal efficiency like that isn't possible using a hydrocarbon motor fuel in an internal combustion Otto cycle engine.

As for the power curves on the batt + gen, like I said way back, this thing is going to get hot,hot,hot right away. That's a ton and a half of energy to dissipate, all while this thing is going to hover? Yikes, I must be tired. Not saying it can't be done, but with most projects like this the calorimetry doesn't add up with conventional chemical engines supported by chemical batteries.

Hope you make it fly.

 

[Skip Miller]

Ok, this I would need to verify independently. The best I've ever seen is a high Q stratified charge four-stroke diesel type dry sump engine that did about 250 g/Kw/hr. If I've done the conversions right, (250g = .44Lb & 1Kw = 1.34 HP, then .44 /1.34 = .328 BSFC) that gives .33 BSFC. Which is pretty remarkable on a hydrocarbon based fuel.

.....

There may be some errors in your calorimetry somewhere. I think a thermal efficiency like that isn't possible using a hydrocarbon motor fuel in an internal combustion Otto cycle engine.

Well it is possible but you will never get the engine off the ground!

http://people.bath.ac.uk/ccsshb/12cyl/

Fuel consumption at maximum power is 0.278 lbs per hp per hour (Brake Specific Fuel Consumption). Fuel consumption at maximum economy is 0.260 lbs/hp/hour. At maximum economy the engine exceeds 50% thermal efficiency. That is, more than 50% of the energy in the fuel in converted to motion.
For comparison, most automotive and small aircraft engines have BSFC figures in the 0.40-0.60 lbs/hp/hr range and 25-30% thermal efficiency range.

 

[rydogg]

What ever happened to this thing? Crash & burn?

 

[steingar]

I call BS on the whole thing. The nanotech is nowhere near this level of application, and he was talking about it years ago. The propulsion sounds suspect as well. A year later there are no photos of prototypes on their site. Reminds me of the Moller Skycar.

 

[Falxair]

I call BS on the whole thing. The nanotech is nowhere near this level of application, and he was talking about it years ago. The propulsion sounds suspect as well. A year later there are no photos of prototypes on their site. Reminds me of the Moller Skycar.

Im glad to say that this will never be a Moller Skycar. No there are no photos on the site, No the propulsion isnt suspect as everybody seems to look at the 100hp genset only and forget about the onboard battery system and its power capacity.

Nanotech is slow and it does take time to get hold of the viable products but to say its BS is just sad. We have spent years researching this, travelling around viable suppliers and getting test data from motor, generator, engine, battery, avionics manufacturers. We have worked with scaled prototypes and done valuable CFD work and before anyone say's the usual "investor money", we have been self funded from day one.

Now, we wanted a working, 100% platform by Christmas last year, it didnt happen and that was down to 2 things, funds and ill health (believe me, working thousands of hours on this takes its toll).

We are working with new manufacturers and suppliers to bring this from concept drawings to reality, it isnt easy, it isnt cheap and Im sorry, but we wont release any other images until the final, WORKING platform is complete, then i will post you a dozen images to remark upon.

Thank you

 

[steingar]

Nanotech materials are still more theory than not, unless you can point me to where I can buy a roll of the stuff. Heck, if I could buy a roll I could probably build an airplane revolutionary in its performance from extant designs.

 

[Falxair]

Nanotech materials are still more theory than not, unless you can point me to where I can buy a roll of the stuff. Heck, if I could buy a roll I could probably build an airplane revolutionary in its performance from extant designs.

If i could get it in roll's we wouldnt be having an exchange of messages... I had to travel to a university many miles from here to get samples and they cost me an arm and a leg, we could only get enough to do a very small test piece and it isnt what is says on the tin. The combination of expensive, long time line production means we have delays and its not just in the materials but also in the resins used as they also need to be of a specific type which cant be purchased off the shelf. While its taking its time in arriving, we ARE working on it.

 

[steingar]

You came to my little university to do it. Because I see what these guys are doing all the time I do have a bit of insider insight, you might say. The folks doing the nanotech are really, really, bright. They are the best at this sort of technological innovation, and they are nowhere near prime-time. Basing your design around their work is like basing in on unobtainium.

 

[Falxair]

You came to my little university to do it. Because I see what these guys are doing all the time I do have a bit of insider insight, you might say. The folks doing the nanotech are really, really, bright. They are the best at this sort of technological innovation, and they are nowhere near prime-time. Basing your design around their work is like basing in on unobtainium.

As stated on multiple sites, the concept images are just that, concept. We have multiple patents to file and the actual Pop Sci images have been altered on purpose to ensure we give zero away, hence we get a lot of people saying its not possible. All i can say is wait and see the final results, it will be very unique and may answer some of your doubts.

 

[Dr. O]

Falx Air, I wish you the best of luck, I really do...
There is a reason for the old saying that the best way to make a small fortune in the airplane business is to start with a big one...
Developing the tilt rotor for the US military nigh onto bankrupted the companies involved - and they were being fed with huge amounts of tax dollars...

From my point of view, you need to have a working power train before you even think about nanotech structures...
You need to solve the problems of the tilt wing mechanicals and main spar - strength, flutter, twist, weight, rotation control, fail safes - first...
Then you need to solve the problem of power delivery from the fuselage to the prop hubs - weight, electrical switching, motors, heat...
Then you need to solve the issues of hubs and blades - foils, weight, pitch control, vibration analysis and testing... Remember you are twisting (yawing) those blades in flight across the apparent wind stream - expect excitement...
Then you need to build a test jig and cycle test the entire power train and props through the range of motion, in gusting winds, temperature extremes, power failure modes, etc...
Once you have the power train proven, you now know what size and shape your airframe needs to be, and from thrust measurements made on a working power train you can develop a weight budget...
Then you have to figure a way to build said airframe from ultra expensive, nanotech composites...
Then once that is done you begin an entire cycle of taxi tests, followed by engineering changes as new and perplexing failure modes are discovered.. Then you go into jump tests of a few feet off the ground, and on, and on...

First, you will need a minimum of 1 million dollars to reach a test prototype - and that is assuming you do it like any amateur homebuilder of aircraft and cut huge corners, pay no salaries to volunteer workers, and get companies to donate their products...
How many decades has Carter Copter been developing his new technology?
And how many products do they have for sale currently?
And a lot of that work was done with NASA money...

Now, having wished you well (and I mean it) I have to point out that the likely hood that you can carry this off as an individual is zero...

denny-o

 

[Falxair]

Falx Air, I wish you the best of luck, I really do...
There is a reason for the old saying that the best way to make a small fortune in the airplane business is to start with a big one...
Developing the tilt rotor for the US military nigh onto bankrupted the companies involved - and they were being fed with huge amounts of tax dollars...

From my point of view, you need to have a working power train before you even think about nanotech structures...
You need to solve the problems of the tilt wing mechanicals and main spar - strength, flutter, twist, weight, rotation control, fail safes - first...
Then you need to solve the problem of power delivery from the fuselage to the prop hubs - weight, electrical switching, motors, heat...
Then you need to solve the issues of hubs and blades - foils, weight, pitch control, vibration analysis and testing... Remember you are twisting (yawing) those blades in flight across the apparent wind stream - expect excitement...
Then you need to build a test jig and cycle test the entire power train and props through the range of motion, in gusting winds, temperature extremes, power failure modes, etc...
Once you have the power train proven, you now know what size and shape your airframe needs to be, and from thrust measurements made on a working power train you can develop a weight budget...
Then you have to figure a way to build said airframe from ultra expensive, nanotech composites...
Then once that is done you begin an entire cycle of taxi tests, followed by engineering changes as new and perplexing failure modes are discovered.. Then you go into jump tests of a few feet off the ground, and on, and on...

First, you will need a minimum of 1 million dollars to reach a test prototype - and that is assuming you do it like any amateur homebuilder of aircraft and cut huge corners, pay no salaries to volunteer workers, and get companies to donate their products...
How many decades has Carter Copter been developing his new technology?
And how many products do they have for sale currently?
And a lot of that work was done with NASA money...

Now, having wished you well (and I mean it) I have to point out that the likely hood that you can carry this off as an individual is zero...

denny-o

Denny, While i answer emails etc, Im not, by any means, a one man band. We have a qualified aerodynamicist who has designed and built six different platforms, mechanical and electrical engineering staff in support and three very qualified business people running the show. We have worked on scale prototypes and we are working on a full scale now.

 

[Henning]

As stated on multiple sites, the concept images are just that, concept. We have multiple patents to file and the actual Pop Sci images have been altered on purpose to ensure we give zero away, hence we get a lot of people saying its not possible. All i can say is wait and see the final results, it will be very unique and may answer some of your doubts.

There are several technical issues you're trying to settle here, why not rescale a bit into available composites and use a bit more power. That way you can get a unit flying and work out the control system problems which you will have. As you have discovered, the nanofiber stuff just isn't there yet, and you have at least a decade before it is available in commercially viable quantities and prices. You can't afford to be on the bleeding edge of this stuff, let NASA and other governmental and space agencies do that. What most often dooms projects like this to failure is not necessarily lack of ideas or incorrect ones, but running out of capital. Build from what's commercially available now and get something flying. If you can make something go, you have a much better chance at the funding to get the Unobtainium materials that will take it from a test bed to a practical machine.

 

[Trapper John]

What most often dooms projects like this to failure is not necessarily lack of ideas or incorrect ones, but running out of capital. Build from what's commercially available now and get something flying. If you can make something go, you have a much better chance at the funding to get the Unobtainium materials that will take it from a test bed to a practical machine.

Yep, and what's the market for this machine? How many people would actually buy a personal tilt-rotor at $x? Figure the price when it gets to market is also going to be 1.7x to 2x.

Not that it isn't cool and intriguing, but it could be that this thing is an answer to a question nobody asked...


Trapper John

 

[bsdunek]

Boy, lots of knowledgeable people here. My question is, why a hybrid for an aircraft? They spend a lot more time cruising than taking off. It seems like the weight of the generators and batteries exceeds the slightly larger engine needed to give the take off performance. It’s sort of like a Pries is OK for puttsing around town with lots of starts and stops and slow speeds, but put it on the expressway for a long trip and its fuel economy is worse than a similar regular car.
I’m not an aircraft engineer so just IMHO.

 

[Henning]

Yep, and what's the market for this machine? How many people would actually buy a personal tilt-rotor at $x? Figure the price when it gets to market is also going to be 1.7x to 2x.

Not that it isn't cool and intriguing, but it could be that this thing is an answer to a question nobody asked...


Trapper John

I'd like one, a personal tilt rotor that I could put on a 60'+ boat deck.... But even more useful would be a 6 place 2400lb payload with 600 miles of fuel (or 12 pax/ 5200lb payload with 1100 miles of fuel.) Those machines I could find a job for, especially with retractable floats or water capable hulls.

 

[Henning]

Boy, lots of knowledgeable people here. My question is, why a hybrid for an aircraft? They spend a lot more time cruising than taking off. It seems like the weight of the generators and batteries exceeds the slightly larger engine needed to give the take off performance. It’s sort of like a Pries is OK for puttsing around town with lots of starts and stops and slow speeds, but put it on the expressway for a long trip and its fuel economy is worse than a similar regular car.
I’m not an aircraft engineer so just IMHO.

It all depends on how heavy your batteries and electric-motive couplings are and how much continuous power you need and how much burst power you need. You would be best power to weight with turbines and gearboxes interlinked in the high torque phases of flight but at the cost of fuel wasted in the low torque phases of flight. If you use it for short jumps, that would probably be most efficient. However with the new LiIon batteries and high efficiency light weight magnet motors built into the prop hub and nacelle, if you only need short term boost power of say triple your cruise torque for say a minute or two just to translate to forward flight for a longer flight then another quick burst of high torque at the end of a 2hr+ flight for V/STOL landing, then you may be better off with small lightweight Diesel generators that put out 110% of the required cruise power. You'd only need about 50% of the fuel for the mission compared to a turbine that could do the same job. If you run high enough voltage you can run small enough cable that you can do it weight efficiently and be able to add range or payload to the craft.