MD600 ROD in Autos

[dragman]

Talking shop with a MD600 driver, reckons ROD during a standard auto is stable at over 4000 feet/min.

Anybody care to confirm that?

[Head Turner]

Never got such high rate of descent when I was practising autos. What the R.O.D. was I cannot say exactly but it must have been around 2600 F.P.M in satandard auto. Out of balance will increase R.O.D.

[JTobias]

Hi there

I can happily confirm that I have experienced autos in an MD600N at over 3500fpm which is where the VSI was limited. It is therefore possible that the rate of descent is greater than that. These were done about two weeks ago and it's an interesting ride.

Joel

[dragman]

Blimey, I thought skydiving had a great groundrush.

Thanks for that

[mfriskel]

Wow- you need to describe that auto to me. What kind of airspeed and NR were you during that auto? Was the trim true? Was that your steady state rate of descent? Is your ship YSAS equipped or not? How high were you, because if I was 500 feet or less (our traffic pattern altitude), and coming down that fast, I would have a hard time looking inside!
Cheers
Mark

[JTobias]

Hi Guys,

I was in a flight test\checkout flight out of shoreham seated as a passenger in the back and also in the P1 seat later on. Autos were conducted on a number of ocassions. Auto speed is 85kts and was initiated in straight and level flight at approx 3000'. The aircraft does not have YSAS (in fact AFAIK it's the only one left in the U.K.)

It's certainly an interesting ride down. It felt quite under control, but the instructor makes a point of showing the VSI which is beyond the 2,500fpm descent mark. You can clearly work out that at 1000' agl you have about 20 seconds to sort your s**t out before meeting mother earth..

I have got photos and some video from the flight, but I can't remember whether I took any during the auto (when I was in the back obviously).

Joel

[Hover Bovver]

Joel,
I wouldnt argue with mfriskel, I think it is safe to say he has done a few autos in the 600:ok:, (Hi Mark how is life treating you) And a few other things as well.

[Sandy Toad]

Mark, Perhaps it's the weight of all those Kilo Steaks you MD guys seem to live on.....;)

[md 600 driver]

hi mfriskel how you doing didnt see you at hai this year


joel
it would agree with hover bover mfriskel certainly knows how to auto the 600 and ive never looked at the vsi in a auto so i cant confirm

how fast is it mark?

[mfriskel]

Hi Hover, Life is treating me ok. Still working like a dog and trying to make a living. Sandy Toad, did you have one of those steaks with me? I plan on being there again for a couple days in July, might have to have another one!

As far as the ROD for the MD600 in autos, they do come down fast, but then that doesn't give you so much time to mess up does it? I would call 2500 to 2700 fpm normal, but for the guys hitting 3500 to 4000+ fpm, you might want to check your technique a little. If you keep your NR at the high green, you will come down a little faster, that will also limit your flare and make the end of the auto a little higher workload. Mid to low green NR is what I shoot for in the steady state descent. In and out of trim transients are common without YSAS and will increase your ROD also as well as play hell with your NR with all the pedal movements. Just for my own curiosity, what part number MR blades are on that 3500 to 4000 fpm machine?

Cheers
Mark

[mfriskel]

Hi Driver,
I was out of the country, spent a lot of time gone between last Oct and this March. When you coming to the good side of the ocean again? :)
Cheers
Mark

[JTobias]

Can't help you on part numbers, but A/C reg is G-NELY.

Joel

[diethelm]

Not sure about a 600 as I was too busy. I have been in a 500 with the IVSI pegged at the 3500 FPM mark during autos.

[mfriskel]

Diethelm,
Was that steady state or transient during recovery from the engine failure? What kind of NR and ASPD did you have? Across town in a normal livery 500E or 530FF we see more like 1400 to 1700 (maybe a little higher at times). I hope you guys are getting these wild RODs as some transient and not in your steady state autos after you get everything cleaned up and heading for the flare.
Blue Skies
Mark

[diethelm]

We were doing entry training from 120 knots all the way down to OGE hover in 20 knot increments. Those rates of descent were during entry training from OGE hover at roughly 6500 feet AGL. Zero airspeed in auto was demonstrated by pedal turns. I have no way to calculate the true ROD other than the IVSI was pegged.

At the bottom, we would end up with similar ROD's of 1400 to 1700 and airspeed of 60 to 80 depending upon what the instructor was asking me to work on.

[mfriskel]

That makes sense, especially if you got some out of trim, increasing pressure or rapid changes in pressure across the static port- the guy above was talking about steady state ROD of 3500 and 4000 fpm.
Mark

[NickLappos]

The biggest single determinate of ROD in auto is disk loading. There is no way a small turbine helo will get 4000 fpm for real in an auto at speeds near Vy. However, a CH-53E will trim at 3500 on its best day (14 psf disk loading)

A V22 will see perhaps 5000 fpm, with its 22 psf disk loading!.