Anyone else thinks this is pretty sketchy?

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VP959
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Anyone else thinks this is pretty sketchy?

#1 Post by VP959 » Fri Jul 29, 2022 9:45 am

Bloke (in the UK as far as I can tell), apparently with no flying or aircraft engineering experience, decides to build a light helicopter in his garage and then teach himself to fly it.

Videos of the build: https://www.youtube.com/playlist?list=P ... 7fEizyygOs

Videos of him teaching himself to fly it: https://www.youtube.com/playlist?list=P ... 25hA1nz9qG

From what I can tell he isn't daft, and seems to have a grasp of basic engineering, but he seems not to have a clue about basic stuff, like designing out stress raisers in highly stressed parts, or really basic aircraft engineering stuff. Leaving aside the legality of doing this (not sure how the CAA would view this - not favourably I suspect) he seems to have a pretty relaxed attitude to flight safety and stuff like basic checks before firing this thing up.

Shame his efforts weren't better focussed on making something safer and with due regard for all the hard lessons that aviators and aircraft designers have learned over the years. He does seem to have got the knack of being able to hover for around 30 seconds now, pretty miraculous that he's got that far without serious injury, though.

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Re: Anyone else thinks this is pretty sketchy?

#2 Post by G-CPTN » Fri Jul 29, 2022 9:55 am

Over the years, we have relied on ambitious inventers to pioneer their ideas.
Without them we would not have helicopters - or, indeed aircraft of any sort.
At what stage do we regulate or prevent them from creating new ideas - or recreating established ones?

How many of us experimented with explosives?

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Re: Anyone else thinks this is pretty sketchy?

#3 Post by Ex-Ascot » Fri Jul 29, 2022 10:47 am

It will be interesting to see how this progresses. No the CAA will not be impressed.

Wonder if he has a wife/potential widow.
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Re: Anyone else thinks this is pretty sketchy?

#4 Post by CharlieOneSix » Fri Jul 29, 2022 11:28 am

Lift appears to be achieved by increasing rotor rpm rather than having a collective control...so it's not capable of autorotation if the engine fails.
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Re: Anyone else thinks this is pretty sketchy?

#5 Post by VP959 » Fri Jul 29, 2022 11:46 am

Disclaimer: I am not an aircraft engineer, but I have built homebuilt aircraft.

This is an example of the sort of stuff that worries me, a still image of the top rotor head:
Rotor head.jpg
The use of what look to be commercial grade zinc plated bolts, the lack of enough thread projecting through the nuts and the absence of any sort of locking device on any of the fasteners, just for starters. The same goes for the whole airframe, none of the fasteners look OK to me, and there are loads of bolted tube joints with nothing to prevent the bolt from crushing the tube. The bizarre thing is that the quality of the machining work looks very good, it's almost as if the chap has a blind spot when it comes down to the basics of safe design and construction.

I applaud those that seek to innovate and expand our knowledge, but this chap has made it clear that his motivation is driven by the high cost of second-hand aircraft. He quoted in one video that he wasn't going to pay ~£15k for a second-hand Mosquito, and wasn't even prepared to pay a couple of thousand for a second-hand Rotax aircraft engine (he bought a used outboard motor from Ebay to get the engine . . .). There's nothing that I can see that is novel in the design, seems to be a more or less straight copy of other light helicopter designs.

Of course, he's free to injure himself in any way he wishes, but I'm not convinced that such a freedom should extend to causing harm to the public if this thing catastrophically fails. Anyone that has had the misfortune to witness a rotary wing catastrophic failure will know well how far broken bits from rotating parts can travel, and the velocity with which they can fly off. He's been running this thing up and testing it in what looks to be his garden, for example:
Testing.jpg

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Re: Anyone else thinks this is pretty sketchy?

#6 Post by VP959 » Fri Jul 29, 2022 11:52 am

CharlieOneSix wrote:
Fri Jul 29, 2022 11:28 am
Lift appears to be achieved by increasing rotor rpm rather than having a collective control...so it's not capable of autorotation if the engine fails.

Indeed, the "collective" is just a power lever that works in the same sense. Only controls are pitch and roll gimbals at the base of the mast plus a pedal operated rudder for (limited) yaw control. My guess is that this thing will just weathervane into wind initially, and only gain yaw authority once there is some forward speed. Whether rotor downwash has some effect on rudder authority when close to the ground I don't know.

If anything fails then this thing is going to fall out of the sky with all the grace of a brick. Given the extremely sketchy construction then the chance of something critical failing seems high. He's already had an engine drive shaft coupling shear off during testing, leading to loss of main rotor power . . .

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Re: Anyone else thinks this is pretty sketchy?

#7 Post by Boac » Fri Jul 29, 2022 12:27 pm

Regarding auto-rotation, I saw that he has to engage a drive on engine start to move the rotors, so he has a 'sort' of a/r (if he ever gets high enough) :))

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Re: Anyone else thinks this is pretty sketchy?

#8 Post by VP959 » Fri Jul 29, 2022 12:35 pm

Boac wrote:
Fri Jul 29, 2022 12:27 pm
Regarding auto-rotation, I saw that he has to engage a drive on engine start to move the rotors, so he has a 'sort' of a/r (if he ever gets high enough) :))
So, with the drive disconnected he could pull back on the cyclic and turn the thing into a coaxial gyrocopter? I would guess that it might be hard to keep Nr up with the relatively low inertia blades (they are pretty short) and the added drag from the belt drive system that provides the contra-rotating coupling between the two rotors.

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Re: Anyone else thinks this is pretty sketchy?

#9 Post by Boac » Fri Jul 29, 2022 12:38 pm

pull back on the cyclic
Confused! I thought it had been determined there was no 'collective'?

PS I did say 'sort'....

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Re: Anyone else thinks this is pretty sketchy?

#10 Post by VP959 » Fri Jul 29, 2022 1:04 pm

Boac wrote:
Fri Jul 29, 2022 12:38 pm
pull back on the cyclic
Confused! I thought it had been determined there was no 'collective'?

PS I did say 'sort'....
That's right, there is no collective, just a cyclic. I was thinking that it might still autorotate in the same way as an autogyro, or bit like a helo in autorotation with the collective fixed, getting enough flow through the disc to maintain Nr by getting the disc at a fairly high AoA. The blades of this thing look pretty much identical to autogyro blades, fixed pitch with just a teetering hinge.

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Re: Anyone else thinks this is pretty sketchy?

#11 Post by CharlieOneSix » Fri Jul 29, 2022 1:36 pm

In the early days of helicopters in UK service, around 1944, the Sikorsky R4 was bought from America and went to the Experimental Unit at Beaulieu. My old boss Sox Hosegood was one of those pilots as was Winkle Brown. Both of them told me that initially when they did autorotations to the ground in those days, having lowered the collective to minimum pitch,they didn't then use it to cushion the landing but they flared hard with cyclic just above the ground to arrest the rate of descent, levelled the helicopter and then ran it onto the ground. Absolutely no room for error! It didn't take them long to experiment with using the collective to cushion the landing after the cyclic flare. One day I thought I'd try an engine off landing in a Bell 47 without using the collective.....but I chickened out and pulled collective to do the landing. :-ss

I don't see any way that coaxial could survive an engine failure once it's much out of ground effect.
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Re: Anyone else thinks this is pretty sketchy?

#12 Post by VP959 » Fri Jul 29, 2022 1:53 pm

Out of interest, how do autogyros manage to land from an engine out without a collective?

They just have a fixed pitch rotor with a teetering hinge head, pretty much identical to the head on this thing. My assumption is that always do a rolling landing if they have an engine out, translating vertical speed for forward speed in the flare. Presumably Nr starts to decay as soon as they flare, due to less flow through the disc, but I assume they have enough rotor inertia for this not to be an issue.

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