Hill Helicopters HX50

[EXDAC]

Originally Posted by Winemaker

Oh come on, I understand I don't have to mine and smelt the ore, I was a mechanical designer in aerospace and marine in one phase of my life. Once 'a' part is produced it must be mated these other parts in an assembly, etc. etc. There is no way Hill is going to let a customer assemble a rotor head or a gear box or make up a wiring bundle or run fuel or hydraulic lines, or .... My point was, if you actually look at the FAA percentage calculator, it doesn't seem possible to assign a 51% 'build' to a wealthy customer who shows up for a two week 'assembly' stay and who will probably be spending a great deal of time at the hotel bar.

You seem to have skirted round my assertion that some percentage of fabrication is easily claimed and jumped to a claim that the builder would not be competent to perform any assembly.

I have no doubt that I could, under supervision, assemble anything that the supervisor could assemble. I accept that it may take more time for me to do it.

[Winemaker]

Originally Posted by EXDAC

You seem to have skirted round my assertion that some percentage of fabrication is easily claimed and jumped to a claim that the builder would not be competent to perform any assembly.

I have no doubt that I could, under supervision, assemble anything that the supervisor could assemble. I accept that it may take more time for me to do it.

I have no doubt you could do the work, as I am also sure I could.

Have you run through the FAA checklist and assigned values to the various sub-groups? When doing so the submitter is asked to assign values to both the manufacturer and the customer as to percentages of work. For example, in the 'Main Rotor Drive System' task list task MR1 is 'Assemble Main Rotor Drive Train to Next Level Structure' and the amateur builder is to assign, from a value of 1.0, a percentage of work to both the manufacturer and assembler.

In this case, I assigned a value of 0.8 to the manufacturer and 0.2 to the builder, as the builder will have had no experience with this assembly and will have to be guided at each step by the manufacturer. This would mean, at a minimum, an assignment of 0.5 and 0.5 if one simply tracks hours and a single manufacturing engineer is on hand; this then begs the question of who is actually doing the work.

How would you assign percentages to such a task? The manufacturer will have to check each torque, each safety wire will probably have to be done by the manufacturer, and Q.C. will have to buy off each step. No, the amateur builder will not be building 51% of this machine. The FAA and other bodies may have agreed to Hill's methods, but this doesn't pass the smell test.

[EXDAC]

I'm about to give up as prejudice is hard to overcome. However, I will state that I can use a torque wrench, I own several, and I used several different factory supplied calibrated torque wrenches when I assembled critical parts of my aircraft. I will also state that my safety wiring is as neat and effective as any typically done by any certificated mechanic.

The assertion that a builder could not torque fasteners or safety wire them is ludicrous. No one checked the torques that I used except at the time I applied them. What I assembled is what I am flying.

I will say once again that the 51% rule does not count hours expended. It only accounts for task performed. If I do all the task under supervision then I did 100% of the task!

[PPRuNeUser469990]

From what I have seen of UK Heli Private owners I would not want them "building" anything. Most don't have the time/inclination to even check NOTAMs

[[email protected]]

Originally Posted by wrench1

Except your point is moot considering the FAA and others have already accepted the HX50 builder process to meet the 51% requirement. But stick your "wealthy" theory if that makes you feel better as it seems that is the only qualifying issue that bothers you and others.

Accepted it because at the moment it is 100% theoretical and not proven in any way shape or form - no doubt there will be very close scrutiny by the authorities of the first 'production' model.

Perhaps at that point the gulf between amateur home built FW and a complex, composite RW will become clearer - if they turn round and tell Hill it must be properly certified, his business is dead in the water.

I have no problem with him building a sexy new helicopter, it is the 'gaming' of the system which is designed to maintain safety and airworthiness standards I dislike.

[wrench1]

Originally Posted by [email protected]

Accepted it because at the moment it is 100% theoretical and not proven in any way shape or form - no doubt there will be very close scrutiny by the authorities of the first 'production' model.

The FAA acceptance was my first question when I was originally asked to look into the HX50. The entire success of the HX50 rests solely on whether the regulatory agencies will accept the HX50 as an amateur built aircraft. And after looking into this and verifying those findings with the FAA here, you’ll find its hardly theoretical at this point. Its also the reason you’ll find him to continually tie in the design to its production as it’s the production process that will define how the major portion or 51% is calculated and recorded in the builders log. And each HX50 will have to separately prove to the appropriate regulatory authority that it meets the 51% requirement.

I have no problem with him building a sexy new helicopter, it is the 'gaming' of the system which is designed to maintain safety and airworthiness standards I dislike.

Curious. Specifically… how is he “gaming” the system when the only system requirement he must follow states the following:

(g) Operating amateur-built aircraft. Operating an aircraft the major portion of which has been fabricated and assembled by persons who undertook the construction project solely for their own education or recreation.

https://www.ecfr.gov/current/title-1...91#p-21.191(g)

Originally Posted by hargreaves99

From what I have seen of UK Heli Private owners I would not want them "building" anything. Most don't have the time/inclination to even check NOTAMs

Perhaps that’s a UK thing. But in my experiences from performing 100s of Condition Inspections on E/ABs and 100hr/Annual Inspections on TC’d aircraft, I’ve found in general E/ABs were better maintained than TC’d aircraft for various reasons.

Originally Posted by Winemaker

The FAA and other bodies may have agreed to Hill's methods, but this doesn't pass the smell test.

And? So what’s the difference between the FAA accepting Hill’s Part 21 methods for the HX50 vs the FAA accepting Bell’s Part 21 methods for a 206 or 412?

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[CGameProgrammerr]

Guys, I've said this before. Factory build assistance for experimentals is NOT NEW. They do this already, where the factory people build the aircraft with the owner's assistance. The owner is not simply left to his own devices. So Hill is not trying anything that hasn't already been done for many years, in terms of experimentals. Speaking from personal experience, the customer primarily does assembly as well as some electrical wiring. Engines and avionics are of course 100% factory (typically Lycoming/Rotax and Garmin, of course), as well as paint and some other things.

The 51% checklist is really for kits, which the HX50 is not. Hill will not be offering a HX50 kit, ever. Kits require things like purposely undersized screw or rivet holes that the owner has to drill out to expand, purely so he can technically say he drilled the holes and thus help meet the 51%. However, that is *not* done for factory-assist builds.

To put it another way, factory assist lasts two weeks, but building from a kit can take years.

[[email protected]]

And each HX50 will have to separately prove to the appropriate regulatory authority that it meets the 51% requirement.

As I said, the approval is theoretical and has to be validated on a case by case basis - are we to believe that in 2 weeks, over 51% of the build can be truthfully said to have been completed by the owner?

The gaming element is that whilst it may be within the letter of the rules it certainly doesn't seem to be within the spirit of amateur self building as most people would understand it. Pressing buttons on a CNC machine in a factory is hardly equivalent to stretching and doping fabric over the spars of a wing for example.

​​​​​​​This is a workaround of the certification system - 'gaming'.

[wrench1]

Originally Posted by [email protected]

As I said, the approval is theoretical and has to be validated on a case by case basis

Not at all. The only reason they must be separately validated is because E/ABs do not fall under ICAO or other aviation agreements plus they have no TC to conform to. This is why a builders log and its supporting references are so important to receiving an AWC. And Hill is ensuring the production process will provide the required results and records for any national regulatory agency to accept and issue each HX50 an AWC. No theory involved, just simple fact.

are we to believe that in 2 weeks, over 51% of the build can be truthfully said to have been completed by the owner?

Yes. However, I think it will be closer to 3 weeks as its my understanding the owners will be laying up various composite members as part of the build process. But as mentioned above, the 51% is not a time value, but rather a percentage of the tasks completed in whatever time frame. And the factory or commercial assist method has been used for decades on many different E/AB aircraft types to include jets. So nothing new on that method or time frame.

This is a workaround of the certification system - 'gaming'.

There are about 15 different FAA certification categories with only several that are accepted under the ICAO and other agreements. So do you believe those other certification system categories are “gaming” the system as well? If so, perhaps you should brush up on your aircraft certification knowledge a bit as each system as their own “game” rules.


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[Pittsextra]

Originally Posted by [email protected]

As I said, the approval is theoretical and has to be validated on a case by case basis - are we to believe that in 2 weeks, over 51% of the build can be truthfully said to have been completed by the owner?

The gaming element is that whilst it may be within the letter of the rules it certainly doesn't seem to be within the spirit of amateur self building as most people would understand it. Pressing buttons on a CNC machine in a factory is hardly equivalent to stretching and doping fabric over the spars of a wing for example.

This is a workaround of the certification system - 'gaming'.

I think this and the owner complaint is entirely separate to this helicopter project.

Wealthy owners of aircraft are not limited to helicopters and actually lets face it on a relative basis any private aircraft ownership and its piloting is expensive v average Joe. Aerobatics is an obvious area where the aircraft has almost no other practical use other than the 20-30 min sortie and the type of flying specialist and almost exclusively done by private pilots in non-certified aircraft, yet the bulletin is hardly chock full of Pitts specials creating smoking holes.

Regarding regulations times change and regulations/attitudes/needs change. I've no idea where the 51% rule originated, nor why it is so sacrosanct - after all would you like the composite elements made via a controlled process in a factory or in a shed with someone trying their best for the first time? Is the enthusiastic amateur in his shed safer any more than he is better at nav with a whizz wheel and chart v an app on a phone?

Its 2025 and usually the smart way is to adopt the regs/rules to the best available equipment / process / environment?

[SansAnhedral]

Originally Posted by VM325

Meanwhile, blades are coming...

https://youtu.be/1bHLYwc-L2Y?si=3Ypprak1aLur3nTn

They hadn't even built any yet??

[CGameProgrammerr]

It'll be a long time before they'll need blades, and while they may likely have to undergo revisions, I doubt they're an area of concern for Hill, unlike the engine.

[PPRuNeUser469990]

Hill have made so many promises that it doesn't really matter if there are any "set-backs" or "delays". Anything like that will be presented as a "small re-design so we get it 100% right" or an "added feature customers requested" etc.

All the Hill updates and videos are always relentlessly positive, and that will never change. There is no room for negativity, criticism or scepticsim in the Hill world.

The engine WILL 'run' by the end of June

The HX50 WILL 'fly' by the end of December.


Hill have staked their reputation (and hence future deposits) on these two promises.

[wrench1]

Originally Posted by Pittsextra

I've no idea where the 51% rule originated, nor why it is so sacrosanct -

The major portion or 51% rule didn't become rule until the mid/late 50s. Prior to that there was no limit. And not all countries hold it as sacrosanct. I don't know if still possible, but at one time you could get an exemption to the 51% rule in Canada for amateur-built.

[SansAnhedral]

Originally Posted by CGameProgrammerr

It'll be a long time before they'll need blades, and while they may likely have to undergo revisions, I doubt they're an area of concern for Hill, unlike the engine.

As someone who has spent a career designing rotor blades, they absolutely should be a concern. Outside of the OEMs there are scant few outfits on the planet that are capable of designing and building a remotely certifiable main rotor blade at this scale.

[ShyTorque]

Originally Posted by EXDAC

Really? It fits under - "Operating amateur-built aircraft,"

Have you over owned or operated an experimental aircraft, or even been in one? I currently own two, one exhibition and racing, the other amateur built. Both have at least the same level of safety as their type certificated equivalents.

The obvious question is - who designed, manufactured and built the engines?

[Bell_ringer]

Originally Posted by ShyTorque

The obvious question is - who designed, manufactured and built the engines?

I asked that but got no reply.
Carrying on that thought. What is the transmission?
Is it a simple reduction gearbox?
Who makes that, and the prop attached to it?

[EXDAC]

Originally Posted by ShyTorque

The obvious question is - who designed, manufactured and built the engines?

My experimental exhibition and racing aircraft has no engine. It is a standard class racing glider. It is a production glider that was type certificated in Germany but, at the time I imported it, there was no reciprocal FAA certification.

My experimental amateur built aircraft has an experimental Lycoming YIO-360 with a non standard induction system, experimental fuel injection, and experimental electronic ignition.

[VM325]

Meanwhile...

You Tube

[PPRuNeUser469990]

Is VM325 CRAN/JH?