Interesting ?
 

As an incompetent but enthusiastic 'metal-mangler' and a helicopter addict, I quite enjoyed this YT effort. - https://www.youtube.com/watch?v=2C-RFeb09Ww&ab_channel=C%26CEquipment

Slightly odd that they hadn't come across Paxolin or Bakelite before and I had never, previously come across the S 52 and that aerobatic capability !:eek:

Is this the rehearsal for Hill's self build program? :E

What could possibly go wrong?

Obviously I can see the potential flaws, but the builder , and his team, have a track record of very competent heavy engineering and his approach, thus far, looks to have the right degree of caution.
The eye-catcher, for me, was the revelation of the S52 'loop' - which looked to be complete and included the inverted portion. I would have seen that as impossible (or extraordinarily foolhardy) in an articulated rotor design !

The 300L is based on the Sikorsky S-52. It is a 3-bladed helicopter. I came close to purchasing a kit some years ago.

It was back in the days of "real" test pilots. Here's a video of the loop.

The pictures of “entering” and “finishing” the loop are a different helicopter from the film footage.

Yes, the one in film footage has wheel spats fitted, as with the still shot on the ground. The background in the other stills also suggests another location.

Is the manoeuvre really a loop? In the various film views it seems more like a 'torque turn' is performed at the apex? Not sure what name such a manoeuvre has?

The poster briefly seen in the video indicates 'Tommy' performed 10 of these 'loops' on the same day.

PS: Parent company of Sikorsky was still named United Aircraft Corp at the time, not United Technologies. The latter was only from 1975 onwards according to Wikipedia.

That is a loop, you dont see the ac spin on its mast axis

Wrench ! - thank you so much for that video. !
'quite extraordinary' goes nowhere near doing justice to what it depicts ! ... and it most certainly wasn't a torque turn !!
What I find remarkable is the almost complete lack of common reference to both the event and the implications. Years after this, Boscombe were making videos of articulated blade behaviour in flight (and in icing) and finding much that was new.
Finally ... the start height and finish height ... the prerogatives of youth ! ! ! :eek:

Ok, I have viewed a few more times and can now also see them as regular loops as Hughes500 also did. Wasn't intending to downplay the manoeuvres either way... and the height...

Did anyone witness Alan Bristow looping the demonstrator FH1100 at Redhill?

So are there any known helicopters in service currently which can exhibit a loop? what would be the height loss after the loop is midway (I would say nose pointing down) till the helicopter stabilises in straight and level flight?

BO-105, Tiger, Apache, Lynx, probably some more. Normaly only flown by test pilots, the military and Red Bull.

Plenty of types are physically capable but will be operating totally outside of all design criteria and fatigue limits.

Nose pointing down is 3/4 of a loop - 1/2 a loop is upside down at the top. Height loss is not so great because a helicopter does not need airspeed to generate pitch authority (like a FW). The control authority of the head can pitch the fuselage up. I’ve never done a RW loop but have rolled inverted and pulled through (from below 40 kts) and bunted 90 degrees nose down, rolled 180 and pulled out. In a 5 bladed Eurocopter product.

Have a look at this chap's work ... https://www.youtube.com/@Ben-Dixey/videos

Here's some examples:

A Bell 407 was looped at an airshow in South Africa.


one of the discussion threads on PPRuNE: Aerobatics in a 407

Next thing you know 212Man shall attempt to convince us it was all done on purpose and not merely because the AFCS kicked off.:rolleyes:

Helicopters tend to accelerate rather quickly when pointing straight down like something akin to dropping a set of streamlined car keys.

Ever peg the VSI?

I happened to witness the incident at Virginia as I was a guest of Starlight on the day. Hard to think it was 20 years ago.How time flies.

I have just been through the old thread and it all comes flooding back.Twenty years ago now. How time flies.

The 407 sat idle for several years in a hanger near ours as there was a huge scrap between tho two owners and their insurers that to the best of my knowledge was never resolved.

Sadly the pilot involved took his own life some years after the incident.

Don't have the numbers, but a Boscombe Gazelle on winter trials in Canada in the 70s managed some very high numbers and an unplanned conclusion. :sad:

Drat - rumbled!

Yes, they do go downhill very quickly with even relatively modest pitch angles. I once hosted the senior design engineer for EGPWS from Honeywell, and we took him on a flight in the S-92. One purpose was to show how obstacle warnings could be a nuisance in a high density environment (lots of NUIs) but we also discussed the Mode 1 alerts and the (then) research into improving offshore modes. The Blackpool AS365 accident was still quite fresh in our minds and I tried to explain how quickly things could escalate. But, words can never replace experience so we carried out a series of dives from about 80 kts, with 5 degrees incremental increases in negative pitch. By 25 degrees he really got the message - I think we were hitting 5,000 ft/min in around 6 seconds!

hit 5000 feet down in an AS355F2... in an auto, it comes down like a greased manhole cover...

ZS-Romeo “Inverted” Bravo

To add to the collection of clips showing helicopters rolling and/or looping, this old footage was brought to my attention:

Sikorsky CH-53A conducting rolls and loops over Long Island Sound in a joint Naval Air Systems Command and Sikorsky trial in 1968:

https://www.facebook.com/reel/1237402674817234

(I hope the Facebook link is retained)

Wow, seeing a big helicopter like a CH53 doing this is impressive, thanks for sharing the link.
TEM must have not included "lets do this at an altitude where we have some margin, just in case"
(Starting the loop @ 1150ft and ending it @ 920ft)

Some interesting (and amusing) background to one of the pilots involved:

https://www.popasmoke.com/ed-creamer/rpg/