Heli skid design question

[whyisitsohard]

Well, a nice esoteric question: in the thread http://www.pprune.org/rotorheads/336473-world-helicopter-championships-2008-a-2.html#post4607973 (sorry for not using the presumably rather good permalink...beyond me.) there is a picture of a helicopter bearing the number "13" and carrying a most peculiar set of skids. The skids look as if they are deliberately designed to prevent them snagging on things: but what? And if my assumption is incorrect, why are the skids so designed?

david

[Lt.Fubar]

It's EC-120 Colibri.

Power lines, fences, roots, anti-skid helipad nets... actually anything a heli can hook on during flight, start or landing. Plus this design have fewer parts, is somewhat stronger and less dragy. As for cons... probably CofG is a bit more restrictive, don't know, will have to check in manual.

[whyisitsohard]

Thanks Fubar.

david

[Lt.Fubar]

You're welcome.

I would personally like to hear opinion from someone who performed run-on landing in EC120 or EC130 - how that skid design compare to classical. Is there bigger tendency to nose-dive or maybe it's more forgiving as it's more sled-like ?

[whyisitsohard]

I'd be interested in that opinion too: the nose dive scenario struck me when I saw the skids. They look very precarious and rather unforgiving.

D

[TRC]

...look very precarious and rather unforgiving...

I knew a girl like that once

[whyisitsohard]

There was a young girl from berlin,
who was terribly un-for-givin'
I knew her one night,
got a terrible fright,
and now I'm just glad that I'm livin'

anyway, merry christmas.

D

[DennisK]

Had a chance to fly the EC130-B4 over the Grand Canyon in October. See the upcoming article in January 'Blades' ... followed shortly by an air test report courtesy David Lewis and Eurocopter at Oxford.

Skids. Yup the front design minimises external interference nicely, while the rear profile contributes to lift. The revised skid gear design has virtually eliminated the one skid low hover too. The Chief Pilot of Maverick Helicopters, (they operate forty-five 130s) tells me the new layout has no adverse effects on an EOL run-on landing and their Grand Canyon business operates at 5,000 ft.

The Fenestron shrouded asymmetric T/R blades significantly reduce ambient noise, which added to the dual channel FADEC engine and controlled variable speed rotor has given the type an 84 EPNdB flyover noise footprint ... being some 7 dB lower than ICAO's Chapter 8 figure and USA's National Parks noise limit for Grand Canyon sight-seeing ops.

She's far from a stretched 120. A 10" wider cabin and an eight seat capability plus a 2,315 lbs payload and luggage capacity up 25%. And I'm not even on the sales team!

Sorry to get all sales excited but I just think she's a fine ship.

Dennis K

[TiPwEiGhT]

Never had any problems with the landing gear on the EC120, run on landings are fine. The only problem I cam across was landing on a mountain covered in heather, the front of the skids are pretty much in line with you arse, which means the nose is closer to the slope then conventional landing gear when conducting sloping ground work. Upon lifting the paint work on the nose got quite badly scratched and some minor damage to the pitot tube. Apart from that I loved it, nice comfortable machine to fly.

TiP

[Lt.Fubar]

Dennis, that B4 look promising for a utility workhorse, got performance of B2, but with the pilot on the proper side, close to door frame - not like in Astar/Squirrel where the stick actuator have to be on the right and look through floor window. But still probably only Heliflight is using it for transport/sling work, why is that ?

Would like also to know its side impact survivability, as the seats are closer to sides than on AS350... but I don't think anyone here can answer that.

[victor papa]

I do not know where the feeling comes from that a B4 performs like a B2. Maybe the older pre 2004 models with the smaller compressor, but we have one of those operating EMS hot and high that took over from a b2 and she out performs the B2 by quite a bit. Despite the higher payload due to the increased max all up weight, she laughs at 58ooft 42 degrees at a B2.(No crit on the B2) Yes, she is not a B3+ butthen what does compare to a B3+? Wait till next year when the B4 is rumoured to come with a Arriel 2D engine-even more horses.

As far as the skids go. We had to get used to not having a reference ie the Squirrel skids, as you can not see them as clearly from the seat as the Squirrels. Had no problems during auto's etc once we got used to the new reference.