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-   -   Hill Helicopters HX50 (https://www.pprune.org/rotorheads/628019-hill-helicopters-hx50.html)

[email protected] 4th Nov 2020 10:11

Presumably that angled drive at the front goes into the MRGB but he talked in the video about taking the power from the rear of the engine.

Does that mean they still have a shaft running forward from the rear and underneath the engine and if so, where is the TR drive coming from?

I can't remember if there was any talk of an electric TR on this but if you take the TR drive from the engine instead of the MRGB you have no TR drive in the event of the engine failing.

ApolloHeli 4th Nov 2020 22:01


Originally Posted by [email protected] (Post 10918543)
Presumably that angled drive at the front goes into the MRGB but he talked in the video about taking the power from the rear of the engine.

Does that mean they still have a shaft running forward from the rear and underneath the engine and if so, where is the TR drive coming from?

I can't remember if there was any talk of an electric TR on this but if you take the TR drive from the engine instead of the MRGB you have no TR drive in the event of the engine failing.

I assumed the mounting on the front to be the direct drive electric starter motor mentioned. I believe the power turbine running through the rear of the engine will be rigged to drive a common MR/TR driveshaft as is the setup in a single Squirrel (through some reduction gears, the power turbine output is translated downwards to the driveshaft below the engine, and the output RPM is also reduced).

https://cimg3.ibsrv.net/gimg/pprune....c36fead779.jpg

tartare 5th Nov 2020 00:52

Plank driver here.
In picture above - assume power then travels to rotorhead by a right angle gear out of picture to the left?
So - does gas coming in actually flow around the lower section of the rotor mast to the face of the axial compressor?

MLHeliwrench 5th Nov 2020 02:53


Originally Posted by tartare (Post 10918987)
Plank driver here.
In picture above - assume power then travels to rotorhead by a right angle gear out of picture to the left?
So - does gas coming in actually flow around the lower section of the rotor mast to the face of the axial compressor?

there is a vertical air intake with a screen or inlet barrier filter fitted to the top of the engine cowl. See pic at this link where the engine cowl is open - https://www.corporatehelicopters.com...0-b2-for-sale/

[email protected] 5th Nov 2020 05:41


I assumed the mounting on the front to be the direct drive electric starter motor mentioned. I believe the power turbine running through the rear of the engine will be rigged to drive a common MR/TR driveshaft as is the setup in a single Squirrel (through some reduction gears, the power turbine output is translated downwards to the driveshaft below the engine, and the output RPM is also reduced).
Thanks apolloheli, I'm very familiar with the set up in the 365 with the Arriel engine but that angled projection at the front of the Hill engine looks like a very strange way to mount a direct drive starter.

If they have gone down the Arriel style route then they have only reduced complexity a little since you need a reduction gearbox at the back of the engine, something they didn't refer to or glossed over.

Arnie Madsen 5th Nov 2020 07:28


Originally Posted by [email protected] (Post 10919059)
Thanks apolloheli, I'm very familiar with the set up in the 365 with the Arriel engine but that angled projection at the front of the Hill engine looks like a very strange way to mount a direct drive starter.

If they have gone down the Arriel style route then they have only reduced complexity a little since you need a reduction gearbox at the back of the engine, something they didn't refer to or glossed over.

That is the first impression I got also .... sounded like they were saying they had eliminated the gearbox ... wow ..... I went back and listened again and it is just the accessory gears for starter - pumps etc.

It is around the 10 minute mark of the video.

cattletruck 5th Nov 2020 09:53

To me the direct drive starter/generator looks like that gaffer tape roll thing just behind the 45 degree angled engine output drive shaft. Perhaps angling the drive shaft as illustrated allows the engine to be installed lower down in the aircraft making it less top heavy.


ShyTorque 5th Nov 2020 10:43


Originally Posted by tartare (Post 10918987)
Plank driver here.
In picture above - assume power then travels to rotorhead by a right angle gear out of picture to the left?
So - does gas coming in actually flow around the lower section of the rotor mast to the face of the axial compressor?


That output shaft speed is labelled @ 6,000 rpm. Main rotor rpm is normally no more than 300 and they have to be mounted on a substantial shaft. It certainly needs more than a right angled gearbox.

tartare 5th Nov 2020 22:42

Good point!
Another reduction gearbox or two no doubt...

Agile 6th Nov 2020 02:21

Arriel 2B has an
  • N1 = 52,110 RPM
  • N2 = 39,095 RPM
  • and an output speed: 5990 RPM

There is no way to transmit 39K RPM in the main gear box as might have been suggested
this requires much different technologies on: the gears, the bearings, the oiling, the assembly rigidity...
much different than handling 6K RPM

note the power is generally distributed as follow
  • 82 % main rotor
  • 10% tail rotor
  • 8 % efficiency losses in gear box + accessories

cattletruck 6th Nov 2020 09:27

EC130 tail rotor drive shaft spins at 6000 rpm, perhaps its Fenestron likes that input speed as it itself turns at 3584 rpm.

Going the other way, the MGB uses epicyclic gears which are very good at converting all that rotational energy into mast torque.

tartare 7th Nov 2020 01:35

Ahhhh - planetary gear system... I see.
Helicopters really are remarkable machines...

Bell_ringer 8th Dec 2020 14:11

https://verticalmag.com/news/hill-he...oval-strategy/

Rather interesting approach.
I doubt many supercar owners, who seem to be the target market, will want to build it themselves.
Sell some kits, then try certify it.

All a bit convoluted.
Sounds more and more like vapourware.

Thracian 8th Dec 2020 14:16

Whoa:
Wait!
495k GBP (well, maybe + VAT + 2 weeks of owner operator factory work at Hill Helicopter's)?
That's about 545k Euros or 660k US Dollars.
And 5000 hours on condition maintenance schedule come as the icing on this cake? Correct me if I'm wrong, I'm not a native english speaker and might have missed some "details".

For a brand new single turbine 5 seater this sound very attractive - if you can live with the "private use only" stamp and if you can wait until 2023.
They say that the "commercial" version of this machine will be available about 3 years later and for about double the price point.

Of course, we'll have to se the flying prototypes in action, but man, this sounds (and only sounds until now) amazing.

Thracian

Bell_ringer 8th Dec 2020 14:55

I guess it depends how your local regulator treats amateur builds, both from owner effort required, resale and flight restrictions.
Helicopters don't have the best track record in this category and were fundamentally aimed at a different market.

An aircraft that has been presented with super-car styling, design and build quality seems quite at odds with amateur building.
$660k buys you a fair amount of already assembled aircraft, though nothing as swish as Hill proposes.

I just find their messaging and sales strategy confused and conflicting.

At $1.3M certified, they are putting themselves into an interesting market but it's not exactly making flying accessible to the masses.
It's also a fair amount of money to invest in something where the reputation needs to survive the problems usually associated with amateur builds.

Nige321 8th Dec 2020 15:32


https://verticalmag.com/news/hill-he...oval-strategy/

Rather interesting approach.
I doubt many supercar owners, who seem to be the target market, will want to build it themselves.
Sell some kits, then try certify it.

All a bit convoluted.
Sounds more and more like vapourware.
I suspect that it wil be billed as an 'experience'.
The only person I know who buys Ferraris just loves his factory visits to see and touch his car being built.
Same with Bentley...

Bell_ringer 8th Dec 2020 16:18


Originally Posted by Nige321 (Post 10943018)
I suspect that it wil be billed as an 'experience'.
The only person I know who buys Ferraris just loves his factory visits to see and touch his car being built.
Same with Bentley...

if its built in a factory it is production built, not amateur built.
most regulators require an experimental aircraft to have been part constructed by the owner.

there isn’t a Super car owner alive who would put in their own spark plugs.

CGameProgrammerr 8th Dec 2020 17:44

Actually that's not true; factory assist (aka build assist) is a real thing. Yes it can feel like cheating but it's legitimate. The biggest caveats for a helicopter that's technically E-AB is it will be more difficult to insure (though the much lower purchase price should counteract that) and it can't be used for commercial purposes. (You can train in it if you're the owner and are the one receiving training because it's your own aircraft.)

I still feel like this thing is a pipe dream, but if they somehow make it a reality than the E-AB version would be a serious competitor to even the R44. But until they have a flying prototype I'll remain a bit skeptical.

Robbo Jock 8th Dec 2020 18:10


it becomes very difficult for a certification body to argue that ‘Oh, it’s a terrible idea, it’s very dangerous, it’s too risky,’ if we’ve got 1,000 or 2,000 of them out there already with an exemplary safety record.”

customers will be required to assemble their aircraft in a “carefully choreographed” two-week factory course
At one every two weeks, how long is it going to be before they approach certification bodies for the HC50? How many 'production' lines are they going to have to ensure they've got the flight hours to say

an exemplary safety record

Nige321 8th Dec 2020 22:32


Originally Posted by Bell_ringer (Post 10943042)
if its built in a factory it is production built, not amateur built.
most regulators require an experimental aircraft to have been part constructed by the owner.

there isn’t a Super car owner alive who would put in their own spark plugs.

Really? Pop along to the next Goodwood or Salon Prive, plenty of owners willing to get their hands dirty.


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