Why are helicopters so expensive!

[Graviman]

I'm just about to have my second flight in an R-22 :cool:. Having about 250 glider flights, and some fixed wing flying, i was suprised by how quickly i felt right at home. The trick seemed to be very gentle corrections, but allow for large trim movements on all controls. I have seriously considered a PPL-H

At £250 an hour, i have to face the reality that i am looking at £5000 before going solo (if i keep up the learning pace). At this stage i start to think along the lines of Skyfox Gazelle Ultralight, or even a return to gliding.

Why are helicopters so unbelievably expensive to fly? As a mechanical design engineer, i understand metal fatigue and tribology, but just don't see why a chopper suffers so. Is it legal restrictions on maintenance? Depreciation of aircraft? Lack of students? Large insurance/repair bills?

I have been a keen follower of Dave Jackson's Synchrolite project, and think he's right with the idea of an easy to fly, low cost design. Is this all that is required to push chopper costs down to (at least) fixed wing costs? Is there anything that, as an engineer, i should be considering to try to help bring down the cost of recreational chopper flying.

Mart - Wannabe rotorhead... :(

[Jack Plug]

Why are helicopters so unbelievably expensive to fly?

1)Regulation. in the pretence that it will improve safety.

Real reason. To stop the great unwashed from doing it and keep the regulators in a job.

This stifles development, means we fly prehistoric designs using engineering solutions from the middle of the last century which are incredibly labour intensive and expensive to maintain and more difficult to fly than necessary(see insurance below).

2) Parts are incredibly expensive allegedly due to certifiable provenance. Expect to pay up to £150 for a £12 bearing. It will not be more reliable nor will it last longer than the £12 bearing but it will have the right bit of paper to add to your huge and growing paper mountain that is required to keep a helicopter in the air. Low volumes mean prices must be kept high to keep the manufacturers in business. The manufacturers are not making huge profits (quite the opposite actually) as the regulators need to be paid.

3) Insurance premiums are high as lots of trainers are written off. Quite a few of these are due to prehistoric devices such as carburettors which are fitted to helicopters because the cost of certifying newer technology is too great. (regulation again being counter productive).

4) They burn huge amounts of fuel due to 1950s technology - development stifled by regulation.

need I carry on???

Rant over

[NickLappos]

The car that runs on water and the 25 dollar an hour helicopter are both urban myths.

The reason why helos cost so much to buy and maintain are due to three inexerable economic factors, all unlikely to change very soon:


1) They are not built in enough numbers to allow the development costs to be insignificant. A new car engine can cost $500,000,000 dollars to develop. It is about as complex as a helicopter, which costs about the same to develop. The S-92, which I am intimately familiar with, cost the better part of a Billion dollars to develop. If you sell 10,000 helicopters the development costs alone (before you buy one pound of aluminum or a light bulb) will therefore add 50,000 to the price tag, if the sharehoilders take not one penny of interest for their risk.
As a thought experiment, ask yourself what your car would cost if the manufacturer only sold 2,000 of them.

2) Helicopters are made of costly high technology, because they won't fly unless they were so light for their payload. A railroad car, empty, weighs about the same as what it carries. Therefore 50% of its MGW is its empty weight. It has no engine, no fuel, no crew, not even a top if it carries ore. Do the math for your helicopter, it has the same ratio! The net result is that the helo is made of delicate, exotic stuff, and you pay for it.

3) Jack Plug doesn't like regulations, until the bolt that holds on the tail cracks, then he hires a lawyer and sues everybody around. Helicopters can't be pulled over to the side of the road if they break. They don't get flat tires, they kill you. So you must pay for the quality control that makes one bolt cost 100 dollars. And the quality control makes one bolt worth 100 dollars.

In short, the fastest way to drop helo prices is to get all your friends and enemies to solo in them. If the helo industry made machines at 10% of the yearly rate as cars, the costs would be perhaps 25% of what they are now.

[TeeS]

Damned fine answer!

Mr. Robinson went a fair way towards it, but look at the hassle he gets on this forum!

TeeS

[Jack Plug]

Nick,
I think comparing the S92 to the R22 is not fair. The development costs to put a fuel injected Lycoming in a R22 are not huge. The certification costs are prohibitive. Thats my point about stifling development.

I think your perspective is more valid in the USA, and I dont have a problem with paying for quality control. Here in the UK we have the CAA, JAR,EASA and god knows who else regulating the industry. I would rather that the skilled senior engineer was working on my helicopter, not filling in a mountain of forms while a junior does the work. Owners in the UK are about to suffer a whole new layer of beaurocracy as EASA regs starts to bite, and it looks as though they will bite hard.
Regulation is a British disease and if there is a rule, we will gold plate it. Twice. And then again for good measure.
Compare charges for FAA services with the CAA.

And I've not started on the tax on avgas in the UK. I bet you don't pay about $8 a gallon for it in the States.

I wish we could fly helicopters for the same cost as you can in the States.

[delta3]

I see two major factors in Nicks statement

1. Economics of scale : not much to do about other than Frank's approach to appeal to the 'masses'

2. Cost of quality: Here I think a lot can be improved. It is not acceptable that quality pushes prices from 12 to 100. An important part in that is information flows, or 'paper work', and this offers a lot of improvement potential. But as said certainly in the EC, governements do not show the way.

d3

[Mars]

Jack Plug:

You were given a fair answer by Nick and chose to ignore it.

You spent most of your first post railing on about certification without reflecting on the facts that: (a) certificating regulations (FARs, JARs and EASA implementing rules) are harmonised - i.e. the same; (a) you do not build civil helicopters in the UK (you used sterling as an example); and (c) that the cost of helicopters is competitive between the US and Europe (accepting that the exchange rate at the moment gives the US the edge).

Nick’s point about the amortisation of development costs is significant and is the reason that most manufacturers would like more rationalisation in the industry. Basically, the market is too small.

[delta3]

Mars

MD going all custom for one customer, also did not show the way. Providing for quality on small batches is not really economic.
Turning an industry that is project based, to series requires
a lot off things to change (=culture). That is what Frank seems to have pulled together well. Should n't he be called the Henri Ford of the helicopters?

The fact that we see over and over again that actual life times of machines are stretched way beyond planned life times shows that too. The way procurement goes nowadays in the US military (as an example, not meant to start intercontinental fights) also points to the same planning issues: what they develop and what they actually (have to) buy today does seem to lack coherence.

d3

[Graviman]

Wow, some really good answers! Guess my query goes right to the heart of helicopter operation.

Agreed with Nick about the cost of quality control, but also agree with Jack about British obsession with regulation. I am, for example, amazed by the R22 servicing costs in another thread - this alone puts £100 on per hour before the instructor breaks even.

The point about training write-offs probably goes to the point about helicopter development for easier control. I was always impressed by the Lockheed work on mechanical gyro control systems - the Hiller was OMHO inferior, since it controlled a teetering rotor and relied on steady flow around the hub. Both offered hands off cyclic hover (with position directly controlling roll/pitch rate).

Regards weight saving materials, i agree but R22 is made from a tubular steel frame. A while back i was actually trying to dissuade D.J. from using carbon fibre, since it has to be carefully used to offer weight benefits over tubular steel. I appreciate the need to develope a special gearbox, and modify engine for chopper installation, but it does look to me very mech like GA technology.


My real interest with this thread, as an engineer, is to understand which areas of (say) the R22 that contribute to the cost of it's operation. Think of this as a design FMECA, where the failure mode is frightening off folks like me who really do want to fly rotorcraft, but are prohibited by the costs...

Mart

[NickLappos]

I really agree with Jack Plug about overregulation regarding many aspects that build operating costs. I was referring to the manufacturer's contribution, but Jack's point is quite true, there is much to trim in the operating costs due to over regulation.

I often note the masochistic pride that flying Brits show as they brag about how hard it is to get a UK license, as though that extra they have to learn makes them better. Perhaps I'm the only Yank who chuckles when you folks ask advice on how to spend another 1000 pounds on some useless bit of trivia you have to memorize so your government will allow you to fly your helicopter.

The almost offensive remarks about US flying schools (who charge about half of the UK prices) is an example.

Invariably, I get push back about how that makes UK pilots superior (I can actually see the monicle drop from their eyes as they post the response!). Accident rates and usage rates show that the US has TWICE the number of pilots and aircraft per capita, and a lower accident rate. These facts then elicit comments about how much crueler the air is in Britain!!

Jack, I agree. I think UK operating costs are driven up by at least 50% because of useless over regulation. I think it is wired so firmly in your culture that you have trouble seeing it, mostly because you ask the government for permission, where in the States, we expect that we have a right to do it, and regulation should be only that necessary to assure safety.

Anyone want to memorize Morse Code with me?

[Graviman]

"I can actually see the monicle drop from their eyes as they post the response!"

Why my dear Sir, if helicopter flying was easy it would mean the end of the British Empire...

Seriously though, you do have a point. The sad fact is that i probably have to consider using the next lesson to convince myself that i can handle rotorcraft flying, then head out State side to get a licence. As it turns out there isn't a 3-axis microlight in the area, so i probably have to go back to gliding to further my experience.

On a beautiful day like this (we do get a lot of cloud), the sky sure feels a lot meaner on this side of the planet... :{

Mart

[pilotwolf]

Perhaps I'm the only Yank who chuckles ...

Well, you ve at least one Brit who chuckles with you!

PW

[slowrotor]

Graviman,
Welcome to this forum. As an engineer you may want to consider working on a project of your own.

Experimental aircraft have little if any government hassles to deal with. The cost could be very low. The problem is that there are only a few helo experimental designs. (about 5, I think) Compare that with over 700 fixed wing experimentals to choose from.

There is the Mosquito ultralight kit from Canada for sale at $20000US.
I saw it fly last year at the Oshkosh airshow. Construction quality looked outstanding. You would need about 10 hours of dual and they deduct $2000 for that when you buy the kit. www.innovatortech.ca

We need more designs. The market is unlimited.

[B Sousa]

Expensive?? All of the above answers plus people have a tendancy to break them into little pieces more often than Airplanes...(the built-in expense being the Lawyers, Litigation etc)

[TheFlyingSquirrel]

Hey Lappos - no more Morse in the exams !! It's all gone !! So there !!

I think a little sour grapes there Nick !!

"George goes in the 101, doo dah, doo dah !! "

( Or should it be dit dah, dit dah ! )

tee hee

[Shawn Coyle]

Flying Squirrel:
There may not be any more Morse Code in the exams, but I'll bet you still have to do AC and DC electrics - and know stuff about turbine engines that is mostly trivia.
While I would agree that the US exams and requirements could be a bit more complex, I think the JAA system is out of control as far as regulation goes.
All of that adds to the expense, but doesn't really contribute to safety or efficiency.

[Graviman]

"...The problem is that there are only a few helo experimental designs...."

I'm a great fan of the ideas put forward by Dave Jackson:

http://synchrolite.com/SynchroLite.html

Seriously, i think we should encourage him in his efforts. He has convinced me about the practicality of the intermeshing configuration. Having read up on Prouty etc, i doubt i could come up with a better concept for advancing chopper design. If the Unicopter ever sees the light of day, i imagine it would revolutionise heli capabilities - particularly regards high speed flight.

I read with interest:
http://www.pprune.com/forums/showthread.php?s=&threadid=151321

"There is the Mosquito ultralight kit from Canada for sale at $20000US."

This looks seriously good! I'm going to look further into this. What where the other kits you mentioned?

Mart

[Dave_Jackson]

Mart,

Thanks for the participation and supportive comments. (The check is in the mail :D ).


Nick,

"The car that runs on water [is an] urban myth."
Heck, the Ballard Fuel Cell car is so advanced it produces water. ;)

I agree with your first point, but must disagree with your second one.

_____________________________


Better craft = Reliable craft
Reliable craft = Safer craft
Safer craft = Enlarged market
Enlarged market = More craft
More craft = Mass production
Mass production = Economical craft
Economical craft = More craft
More craft = Development amortization
Development amortization = Economical craft
Safer craft = Easier piloting
Easier piloting = Minimal regulations
Minimal regulations = Inexpensive licenses
Inexpensive licenses = More licenses
More licenses = Enlarged market


One essential equation is missing from the above recursive loops;
Advanced technology = Better craft

While industry is marginalizing its engineering and manufacturing departments for the sake of its accounting and marketing departments, and while disillusioned governments are give up the funding of rotorcraft research, where is this advanced technology going to come from?


Dave

[NickLappos]

Dave,

There is no higher technology that that in most modern helicopters, at tremendous cost. The structures on the S-92 (I use this example because I am most familiar with it) were designed to standards that only existed in draft form, and it is leading edge. Somehow, you have decided that no high technology exists in the helicopter industry, and I don't know where you got that.

Certainly, the very light helo market has relatively low tech helos, based on designs that are 40 years old, but nobody wants to pay for the higher tech solutions that exist for this segment. That set of equations you pose is particularly simplistic, frankly.

Reliability is almost purely determined by the number of parts, and I cannot imagine a better way to fit more parts in a given volume (and thus fit less reliability into that volume) than to build a syncropter!

[Jack Plug]

Graviman,
Good thread. Both Shawn and Nick have supported my view that overregulation needlessly pushes up costs so there must be something in it.
My original posts were a bit over the top but were designed to be provocative to get my serious point discussed.
I do believe that there would be more money for development and safety without the industry carrying the burden of an army of non productive, obstructive, ill informed regulators. I am realistic enough to know that things will only change for the worse in the future. We gotta live with it.

[Wood Cutter]

Good topic with good debate occuring.

Dave's design of a synchro design has merits, and I shall watch with interest.

There is a Taiwanese company doing the rounds of the air shows (Dubai at least) flogging their coaxial design with 2 engines. See http://www.ezycopter.com/

They have just started flight testing with remote control, and it looks OK so far as the videos show. Sales are expected later in the year, with costs around $30K.

A two seat model is to come as well, that will be interesting to observe leter.

Hurry up and wait!

[Dave_Jackson]

Nick,"Somehow, you have decided that no high technology exists in the helicopter industry, and I don't know where you got that." High technology exists in the helicopter industry, but as is typical, most of it is acquired from outside the industry in question. However, the rotor, its blades, its flight-controls and its configurations are exclusively within the domain of the rotorcraft industry. I strongly believe that the potential for features such as; lateral symmetry, active blade twist, extreme rotor rigidity (wingless 'compound' configuration) etc., have not been effectively pursued.

"Reliability is almost purely determined by the number of parts, and I cannot imagine a better way to fit more parts in a given volume (and thus fit less reliability into that volume) than to build a syncropter!" A couple of abbreviated rebuttals. Rotorcraft should be incorporating more composite construction, since one of it's advantages is the reduction in part-count. The power-train of a single+tail rotorcraft and a twin-main rotorcraft will have a similar number of parts, but, the twin-main rotorcraft will have the advantage of fewer different parts.

Dave

[212man]

I don't think cheap shots at the JAA licencing system contributes much to the discussion and only serves to fuel people's misconceptions about what causes the costs. Does anyone truly belive the cost of the pilot licence has anything to do with the subsequent aircraft operating cost, or to any meaningful degree?

The basic cost of purchasing a helicopter is pretty constant, but taxation rules may affect the final cost. Same for spares I would suggest. Insurance will vary from location to location, but that is not regulation. Fuel prices will vary hugely, but mainly due to taxation; not regulation.

Operating costs at an airfield will vary due to hangar rental, landing fees, office rental etc but they are not regulatory costs. Airfields are businesses and will be subject to their own operating costs, which in a small densely populated island with high 'real estate costs' and local taxation, are likely to be significantly higher than say, Australia, the USA or RSA.

Instructor costs will reflect salary and this will reflect industry norms that arise from the local cost of living.

The point is that helicopters are built in small numbers using expensive componants that require frequent replacement. That makes them inherently more expensive than their fixed wing counterparts. The same certification rules apply on both sides of the Atlantic (as Mars said above) so to use the expression 'over-regulated' is vague, simplistic and far from helpful. If there are specific regulations that directly affect the cost of operating an aircraft and which do not have an equal or similar regualtion elsewhere, then let's have them pointed out and analysed.

[delta3]

Regulation example

The Belgian AA, decides so far not to honour the 2200 TBO for the R44. Cost increase around 10% of depreciation part.

So : Information flow and Information treatement not only doubled but apparantly dissonnant.

Indirect consequence : competition falsified

Free market reaction : register them elsewhere ?


d3

[ATN]

212man is right. The costs of licensing and recurrent training are marginal as compared to the overall costs of helo operations. In fact training is the key word for efficiency and safety, and is actually an investment, not a burden. If there was no regulations, training, basic and recurrent, would be reduced to a bare minimum with the profit only driven managers we have in the industry and eventually the global cost would rocket up the sky.
The first cause to blame in my IMHO is the maintenance cost. Helicopters are just not reliable. They require many man hours to perform inspections and parts changes, programmed or not. How many engineer hours to get a Dauphin, S76, Puma, not to mention S 92 or EH 101 in the air ? That takes its toll even more than the purchase price. Look at all that has been changed on one aircraft after 20 years of operation, it has been almost completely rebuilt, not talking about accidents.
This situation is specific to helicopters - and astronautics.
Sure the themodynamic laws and physical stress on the components are the primary factors, but also maybe the manufacturers have gone - or are going too far in the direction of chasing the last kg there, saving the last drops of fuel here, pushing the engines to the last degree of TOT, ending up with undersized aircraft oeprated to the limits. Maybe time has come to trade some performance for reliability.

ATN

[slowrotor]

"Maybe time has come to trade some performance for reliability."
ATN has it exactly right, at least in my opinion.

The current system is fine for the rich. Nick has customers that are millionares, billionares or trillionairs (US government) and they buy at any cost apparently.
Not so for the average guy.

In this county there are probably 50,000 cars, 2000 yachts and maybe 100 airplanes. No helicopters.
More helicopters of any type are needed. High speed is not required for much of what a helo can do.

Graviman,
Do a search on Ultrasport for another ultralight helo. I do not recommend this design, too many problems with component design. The low disc loading is good however.

[Graviman]

Some really good answers folks! Pleased to see that there is still so much interest in helicopter costs. Please don't forget that i am an impoverished engineer, and cannot afford the budget to fly an S-92! (But wouldn't shy away from the opportunity ;-) )

"...I cannot imagine a better way to ... fit less reliability ... than to build a syncropter!"

I'll start another thread on this, since i'd like to get others views on this config anyway...

"Both Shawn and Nick have supported my view that overregulation needlessly pushes up costs..."

Looks like this is a large part of the costs then.

"...Taiwanese company ... flogging their coaxial design with 2 engines."

Worth considering coaxials in the next thread, definately.

"The point is that helicopters are built in small numbers using expensive componants that require frequent replacement."
"Maybe time has come to trade some performance for reliability."

Maybe. I'm with Dave about the idea of a very easy to fly machine though. If it's easy & reliable new markets will open up.


Also found: http://www.ultrasport.rotor.com/

Thoughts anyone?

Mart

[Dave_Jackson]

slowrotor,

The quest for enhanced reliability is a good. :ok:

Excluding the ability to increase the life and safety factors of existing components, what other improvements do you feel will contribute to a more reliable craft, and perhaps reduce it's price?

Dave

[Hughes500]

Nick I hate to differ here, but no higher technology than in a modern helicopter - what rubbish ! The R44 ( less than 10 years old ) uses an engine designed in the 1930's that uses 1Qt of oil every 3 hours. If that was your car you would be sueing the manufacturer for " not fit for purpose ". as for reliability , my car engine will go for hundreds of thousands of miles without missing a beat. I fly for one of the large rally teams, when their engineers looked at a Lycoming engine they laughed, one even asked what a magneto was !!! Incidently I do not fly Robinson products.
Lets face it the average punter does ot fly an S92 !

[Jack S.]

......Rotorcraft should be incorporating more composite construction......(Dave Jackson).
Maybe have Burt Rutan involved, get him to build something that flies twice as fast for half the cost and what the heck, maybe around the globe on a single tank of gas.

[Chiplight]

What were the other kits you mentioned?

The Helicycle http://helicycle.com/ is a great, turbine powered single place kit for about $35K, which includes the modified T62 Solar turbine.
I own one, but have not installed an engine yet. I am considering selling, turbines not being in my budget, but that's for another forum, I guess.

Here is a nice pic of one flying, of which there are more every month. I wish I could afford to finish this project, because it really is a lot of helicopter for the money.

http://helicycle.com/Flying%20Ships/Bob%20N3375C%20Bushman2.jpg

[Graviman]

Me likey! Not sure about running costs of a turbine though. Somehow the idea of an engine whose turbo expander blades are inevitably creeping towards tensile failure sounds like a good way to gobble up cash. Any thoughts?

One of my major suprises is that there are fewer rotary engine based rotor-wings out there. I can think of at least one aero engine project that is based on the Mazda RX7 engine (don't have link to hand). These strike me as both very reliable and light, and there are versions that burn diesel - although i'm not sure if these are compression ignition or spark ignition of diesel spray. Rolls even had a twin rotary engine project to increase the compression ratio, but i don't believe it went to production - shame really. A turbo rotary would go some way towards improving combustion initiation, making it ideal for heli. Maybe this would finish your project...

Mart

[slowrotor]

Graviman,
You have mixed up my comments about two ultralight helicopter designs.
Let me clarify:
The Mosquito I have seen fly at the Oshkosh airshow. The workmanship appears very good but of course we have no certainty with any non-certified product. I intend to follow this company as they get more experience.

The Ultrasport does not show at Oshkosh any more. I dont think they can keep it flying long enough to show. I was going to buy one, then I called a couple owners and found that parts only last a short time. (such as main gearbox lasted 10 hours to name just one part). The problem with Ultrasport is this: the current owners are not designers and they have little ability to fix the problems. They will sell the products anyway and when you complain to them they will reply: "Well you know it is experimental" Buyer beware. One owner told me that he liked his little Ultrasport but just would not go higher than 15 feet!

Graviman, maybe you could edit your comments about the Mosquito. Thanks.

[Chiplight]

Graviman,

The turbine is de-rated to less than 100 hp, which may increase the life of the wheel- I don't know. I think there are a dozen or more currently flying with this engine and it seems to work extremely well. Only one owner has opted to use a different engine. He installed a fuel injected 3 cylinder Hirth 2-stroke. It also performs well, but obviously has more vibration than the turbine. The prototype flew on a Rotax 618 2-stroke, and was tried with a 912 4-stroke(too heavy.)
While I have seen a picture or two of Mazda Rotaries installed in MIni 500's and Scorpions, they always seem to be hearsay-you never actually see them flying for some reason.

I , too have followed the progress of the Mosquito ultralight. I have a ten year old issue of the PRA mag with a feature article on it. What strikes me as odd is that I can't find any evidence of a single one flying other than the factory demonstrator. I stand to be corrected if someone knows otherwise.
It looks like a deceptively simple ,yet elegant design.

There are definitely many Helicycles in the air and the company is continuing production despite the demise of BJ.

The Helicycle is about $35K, like I said, but add the cost of instruments, radios fancy paint job, interior, lights, trailer, various ground accessories, etc and the cost could be closer to $50K.
From owners reports, the ship is fast, autos well, has a very smooth rotor, and is a real show stopper wherever it goes. Plus it whines when it starts up, which is a sound that seems to release testosterone directly into the brain.

[Dave_Jackson]

Excerpt of an e-mail from Charles LIN, the principle of Ezycopter; " More than 10 yers ago I started the Ultrasport program. I left it to Mr. Lai about 8 years ago."

From correspondence and conversations with John Uptigrove, the developer and builder of the Mosquito, he appears to be a very serious and sincere person. No BS.

Chiplight,
Has the reason for BJ's accident ever been determined?

Dave

[Graviman]

"You have mixed up my comments about two ultralight helicopter designs."

Post edited, thanks for the clarification Slowrotor.


"The turbine is de-rated to less than 100 hp..."

Lowers TET, and RPM presumably, so should help.

"...prototype flew on a Rotax 618 2-stroke, and was tried with a 912 4-stroke(too heavy.)"

Interesting, Chiplight. Did you consider the 3 cylinder Hirth 2-stroke? 100SHP strikes me as low for a GT, since internal aerodynamics limits the efficiency of the design.

Norton aero rotary engines still trade, under a different name (now based in Gloucester UK, but i don't remember the name). Maybe you could consider this as an option to complete your project. I don't imagine the 100SHP to be a problem, since the Commando bike was about this power.

I can see why you like the sound of turbine spool-up though...

Mart

[Chiplight]

Lowers TET, and RPM presumably, so should help.
Right, but an APU turbine is never going to win any awards for being a fuel miser.
Did you consider the 3 cylinder Hirth 2-stroke? 100SHP strikes me as low for a GT, since internal aerodynamics limits the efficiency of the design.
I've considered it, but at $7000+, the cost isn't that much lower than the turbine, and it doesn't whine. Also, I heard it wqas tough to engineer the mounting and fit the hoses and muffler. Then there were frame cracks- then when Hirth came to help tune the engine , they burned a piston. At this point the turbine is less of an unknown. A s for the turbine, the gov is electronic and loss of power means the engine shuts down. I think I'd want to incorporate a small backup gov with its own battery if it were my ship, or some other means of maintaining fuel flow without power to the valve.

Norton aero rotary engines still trade, under a different name (now based in Gloucester UK, but i don't remember the name). Maybe you could consider this as an option to complete your project. I don't imagine the 100SHP to be a problem, since the Commando bike was about this power.

Thanks, but I've already purchased the original engine that BJ was suggesting- A Rotax 700cc water cooled 2 cylinder with tuned pipe.
BJ had lots of trouble with jetting and ignition timing, etc and had a bunch of engine outs during testing.
He never completed testing because he switched to the turbine.

I don't want to find myself in the trees because of a seized engine that I didn't tune just right- so I'm holding off. I'll keep an open mind about the rotary.


Dave,
I don't think the exact cause of BJ's accident is known.
However, the fact that he was flying low over the water at high speed kind of speaks for itself, in my book.

[Graviman]

For personal fun, i really like the idea of the Mosquito ultralight kit from Canada. But, I'm also interested as an engineer trying to understand the limitations of the technology. Thoughts on keeping cost down for general purpose heli design so far:

1. Keep helicopter design simple, with seriously overdesigned parts. The more design life hours the cheaper to operate. Better depreciation loss too (hence cheaper flying hours).

2. Investigate alternative powersources that are better on fuel, and (ideally) low maintenance - this suggests modern diesels.

3. Consider mechanical stability control mechanism, to reduce pilot hours to solo. This also seriously improves retraining/maintenance and insurance costs.

4. Improve machine/rotor efficiency for greater performance range for cost/fuel. Means a cheaper machine has greater market appeal, so becomes cheaper to build.


I'm a great fan of the intermeshing project, as proposed by D.J. but am concerned about the level of complexity/cost that could creep into that project. My thoughts turn to maybe a modified R22 Beta, with a modern diesel engine and gyro stability system. The rotor system could probably also benefit from some aerodynamics, with flexible blades and tip trim. Maybe even a 3-blade rotor, with hub as proposed by DJ.

I appreciate that this level of project would probably end up having to be done by Robinson themselves, but would like others feelings as to the general approach. Any thoughts?

Mart

[Dave_Jackson]

Mart,"I appreciate that this level of project would probably end up having to be done by Robinson themselves" I've got to disagree.

The difficulty might be the necessity of finding engineering people who specialize in specific fields such as; composite construction, transmission design, etc. and who also have an interest in rotorcraft.

I'm a great fan of the intermeshing project, ..... but am concerned about the level of complexity/cost that could creep into that project I don't think that a twin main rotor configuration is necessarily more expensive just because it has twin main rotors. In fact, it should have an advantage because it involves large production runs of fewer different parts. A brief discussion with a cost accountant at your firm can expand on this.

"would like others feelings as to the general approach." Three thoughts.

1/ The critical components could be grouped into one ' Principal Assembly'. In addition, the owner/pilot cannot work on this package. He can only inspect it and/or send it to an authorized company for repair or rebuild. The rest of the craft is his concern.

2/ This Principal Assembly should consist of the; rotor hubs, the transmission, the flight-controls and the blades.

3/ A twin rotor configuration, such as the coaxial and the intermeshing suit this requirement for a compact 'Principal Assembly'.

The coaxial Easycopter is an example of this.
Last week an e-mail was received from them and it offered the following to anyone who is interested. "Now we have put together our first video CD showing EzyCopter in action during testings, and I would like to send it to you, FREE! You may want to forward this email to your friends to also receive a free EzyCopter development video CD by subscribing to the EzyCopter by Yoshine Mailing List." Those that are interested might be able to respond on the Easycopter web site, or send me an e-mail directly and I will reply with this offer.

Another example of this ' Principal Assembly' idea, as applied to the intermeshing configuration, can be seen here (http://www.unicopter.com/Dragonfly.html) and here (http://www.unicopter.com/Dragonfly_Organization.html). This is not a recommendation for the Tri-teetering hub. It is a reccomendation for the general araingment.

Dave

[Graviman]

"I don't think that a twin main rotor configuration is necessarily more expensive just because it has twin main rotors."

No, but i am worried about extensive use of composites in the structure (vs R22 steel frame) and complexity of Independant root/tip control. Don't get me wrong i really do like the project, but i really can't see even the interim design as being low cost due to complexity of design and level of development this is likely to require. Perhaps i'm very much mistaken, since i'm not fully composites knowledgable, but a walk round the R22 reveals this to be GA technology carefully implemented.

Even so, i gather the R22 is approx £120'000 new and guzzles £1000/month of fuel - i baulked at the figures. That's a lot of money sitting in the hanger on a rainy day. With this in mind Unicopter has to be seen as a high performance craft, with price to match. My objective here is a cheap to learn in trainer/utility helicopter - i think even you would have to agree Synchrolite doesn't really fit that bill.

I do like the Principle Assemby idea though. I can certainly see how a small group of engineers could retrofit a powertrain/rotor upgrade to an existing design. Have you ever considered a synchropter conversion (ideally still with gyro hover stabilisation for reduced hours to solo) for an R22 or other? Yes seriously - since this reduces much of the ground work.

BTW Ezycopter video sounds interesting. Do you have the disk already or does it have to be ordered?

Mart