Autos

Problems or things to know about flying the Hiller.

Autos

Postby Guest » Fri Mar 24, 2006 12:55 am

Hey people good to hear from fellow Hiller users, lovers haters, and everybody else. I'd like to know how to do a full down auto, I've never tried one or had one demonstrated in my Hiller 12D. Seems to me that it would be quite tricky as my ship really comes out of the air fast. My instructor has said there's no use in going full down if you can recover at 3 ft, I think he's right as the risk isn't worth it. Still I'd like to do some I know everybody else is doing them, to me it seems like I'm missing something.
Do the Hillers you fly auto well? Mine has -3 m/r blades I don't know if that makes any difference, also I'm a 400hr rotor pilot with 60 hrs in Hillers. Maybe I shouldn't worry about it what do you think?


Ricky
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hiller autos

Postby tcamiga » Fri Mar 24, 2006 7:31 am

Hi Ricky

Don't do any autos to the ground until you have found a competent instructor.

The Hiller is fine for this type of op and when I used to train pilots on them I often did 20 or 30 engine off autos a day with the students.

I consider an engine off auto safer than a power recovery.

I'm in a rush as am heading off to watch a world cup Triathlon for the weekend.

Will reply on return.

In the mean time - if you trained on an R22 it's a possibility you have attended a safety course or your instructor walked you thru the use and storage of energy in the machine. Nothing changes for the Hiller - the same principles apply.

If you don't have this knowledge - do some research on the net.

See U next week

safe flying

Tc
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Postby Hillerbee » Fri Mar 24, 2006 12:15 pm

Full down autos in a Hiller are quite easy, but uncomparable with R-22 or Schweizer.

Autorotation speed 43 knots.+- 5 knots depending on the situation. Rpm depens on the load but low or middle. If it's to high you have to raise collective obviously, but the zero pitch setting of the blades might be wrong as well. If you're very heavy loaded and the air is dense you'd have a high rotor RPM. (which would be normal under that condition)

If your speed gets below 30kts don't flare, you will fall through and get a tailstrike and chop you'r tailboom most likely.

The flare should be much higher, you have a very long tailboom and get a tailstrike quite easy. If you don't flare enough (agressive) it will fall through. If you flare to agressive however it will climb (a lot). So the judgment of flare intensity and height are key. You start you're flare 75-100 feet it all depends on conditions. Level out very very important and it just sinks to the ground and like a hovering auto raise collective slowly to soften the touchdown. With your flare you try to get rid of the high descent rate and forward speed. So very important start much higher with the flare.

I WOULD NOT DO THIS ON MY OWN. Once you practised them with an instructor, you maybe could but I'd suggest practice with an instructor a couple of times a year.

I teach them to my students (from PPL level) because I think you should know the real thing and it will not only save you, but also the helicopter.

Hillerbee
Hillerbee
 

Postby Plumberpilot » Fri Mar 24, 2006 5:38 pm

Tc
From the Gallery forum.
Please explain what "low green" means, are you talking low rotor green? If so then yes I'm using too high of a rotor speed @ 350-380 rpm. Will the flare bring rotor speed up from there easily? That would help explain my high decent rate I guess. I've been keeping the airspeed @ 45-50 kts so I guess that's a little fast as well.

Hope you have a nice weekend.

Thanks
Ricky
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Postby Hillerbee » Fri Mar 24, 2006 6:39 pm

43 kts gives you the best glide/descent rate. If the rotor RPM is high when you have collective full down that means, you will come down a faster. You can either chuck in a little bit of collective or have it tracked properly (the zero pitch setting should be adjusted, pitch links) In the service manual it says exactly what the RPM should be with a certain load and temperature and height (when you enter). When I talk about lower green or top of the green I mean rotor rpm either (low = 320, high = 395) D/E-Model (300-360 A/B/C model)
Hillerbee
 

Sled Autos

Postby tcamiga » Tue Mar 28, 2006 11:56 am

Hi Ricky

I'm back!

Hillerbee is giving you good info which I might put in another way:

Based on a 12E with 03 blades and HIGH skids:

When we were training Hiller pilots full time (pre - R22) all engine off landings (autorotations) were to the ground (grass beside the runaway).

20 -30 a day was normal and there were zero accidents.

It was better on the engine rather than to come down with idle power followed by the thermal shock and torque load of a power recovery. (The VO 540 crankshaft has about 11 degrees of twist built into it and it straightens out at operating revs.)

Run on speed was never zero IAS - always a min of 10 Kts. Max recomended smooth surface ground contact speed is 43 kts (avoid rapid loweing of collective at speed in case the skid gear gets left behind if you hit a rock or obstruction!)

If you are familiar with a HV chart you will probably be aware that the R22 is most efficient at 53 Kts. The 12E is most efficient at 39 Kts - no matter if it's power on or off.

For an engine off landing, we call this speed the "gate" speed - the minimum IAS for a machine to convert its forward energy into Rotor RPM RRPM and make a normal safe landing - provided the RRPM is in the green. The less IAS the more unsuccessful the landing will be.

However - most manufactures recommend a higher gate speed to cater for unfamiliarity, low type hours, shock etc. The higher IAS allows more energy to be fed back into the Rotor system during a progressive flare - but the trade off is a higher rate of descent. For the R22 this is 65 Kts and the 12E it is 45 -50kts Kts.

The range speed for a 12E is 70 Kts.

Notice I haven't mentioned RRPM as yet.

Hillerbee is right in that you should never fly any helicopter unless it has been rigged correctly for Autorotation. He also points out quite rightly that in a stabilised Autorotation - collective full down - the RRPM will also stabilise (provided it has been rigged correctly) at different speeds depending on a number of variables. Usually AUW at the time determines this.

I haven't got a 12E maintenance manual at the moment to quote the rigging chart but I do know the R22 one so all you need to do is get the manufacture's recommended IAS and you will have an idea of the procedure.

For the R22 and Hiller 12 - be absolutely and pedantically critical and accurate with your AUW calculations as a few extra lbs here and there will upset the calculations.

Once the weight is worked out - fly the machine to about 1500 Ft AGL - due your clearance checks - set the Altimeter at 1013 mbs- then full carb heat and enter Autorotation.

Stabilise and balance at the manufacture's recommended speed (50 Kts in the R22) and note the following as you pass thru 1000 AGL:

OAT

IAS

Exact RRPM

Indicated altitude.

Time since engine start (to work out how much fuel has been used and therefore a revised AUW)

Then smoothly engage the engine, normal landing - Carb heat off before passing thru transition.

The M & Overhaul manual will have a chart for U to enter the data - keep adjusting RRPM with Pitch links until it meets requirements for weight etc.



Now that the RRPM are spot on you can try the following with your instructor:

Stabilised Engine off landings at max AUW, mid range weight and low fuel - note the different but normal RRPM.

Max Range Autorotation (above 500 AGL): 70kts and use collective to maintain RRPM at 320 - 340 (make sure that the throttle remains shut as you raise the collective during any practice exercises.

Min range Autorotation (above 500 Ft AGL): raise nose until 10 Kts IAS and hold attitude. At 500 ft lower nose to 50 Kts. Control the RRPM with collective to maintain 340 - 360.


Commence a progressive flare at 150 ft AGL (collective full down) - practise using no collective in the flare (it acts like a brake and slows your RRPM - which in the real thing you need every rev of). Only use collective to cushion landing onto ground, top of tree, water etc.

In other words you can't pick your ideal landing spot in an emergency and in fact may need to drop into a hole in the bush or between trees or buildings etc where revs make the difference to personal damage.

Hope this gives you food for thought.

More 2 morra night

Tc
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Postby Plumberpilot » Tue Mar 28, 2006 8:31 pm

Tc

I'm understanding what you're saying. But a couple of preliminary questions, what is AUW and also why full carb heat before entering the auto? I've never heard of applying carb heat prior to entering practice autos is that common procedure for D mod. as well as E mod. and where does that recommendation come from?

Thanks
Ricky
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Postby administrator » Wed Mar 29, 2006 5:17 am

You always, in every helicopter or fixed wing apply carb heat when you reduce power under 20" of Manifold pressure. You're more likely to get carb-icing with low-power settings. On a normal approach you take it off again at about 100-150 feet, to have 100% power when you land.
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Carb heat

Postby tcamiga » Wed Mar 29, 2006 8:33 am

Hi Ricky

AUW means All Up Weight at a period in time.

Eg it could be 2800 lbs but equally it could be 2550 lbs.

Carb heat is your life saver and a way of spending less Dollars on your engine.

Go to the link for an explanation:

http://brumbyhelicopters.com.au/carbheat.htm

Hope this helps - no problems with any questions if you want to keep them coming.

Tc
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rearwards autos

Postby tcamiga » Wed Mar 29, 2006 8:44 am

Hi Ricky

another to ponder:

A rotor disc is a rotor disc - I taught this manouver for years to all students in the R22 and 47.

Using the rule of thumb of 400 ft for every 90 degrees of turn in the R22, the question was raised how do you land in an area that is just passing under the machine when at 800 ft AGl above 53 kts and the engine quits.

Enter normal engine off configuration and keep the Cyclic coming back smoothly. Trading Fwd energy for Altitude, the machine will not loose too much altitute and MRRPM will stabilise within limits.

You will feel transition go and then return as the disc takes the machine backwards. The nose will pitch down when this occurs.

At this point you will see the touchdown spot and can judge how long to hold the "rearwards flight attitude."

Then - cyclic forward - thru transition, nose down quickly and smoothly down (quite a bit) to gain above the flare gate speed of 53 kts, cylic smoothly aft and hold the IAS above 53, flare and land. Simple.

Similar deal in 47 and Hiller - just use the appropriate speed for the last part of the autorotation.

I never use collective in the flare before touch down as I consider it to be a "Hand Brake" on the Rotor energy.

Think about the advantages of this if you have to drop into a vertical hole in the bush from 50 ft AGL .

Tc
Last edited by tcamiga on Wed Mar 29, 2006 8:29 pm, edited 1 time in total.
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Postby Hillerbee » Wed Mar 29, 2006 5:50 pm

"I never use cyclic in the flare before touch down as I consider it to be a "Hand Brake" on the Rotor energy. "

tcamiga could you please explain, or to do mean collective?
Hillerbee
 

Postby tcamiga » Wed Mar 29, 2006 8:28 pm

Hillerbee wrote:"I never use cyclic in the flare before touch down as I consider it to be a "Hand Brake" on the Rotor energy. "

tcamiga could you please explain, or to do mean collective?


Hi Hillerbee

Thanks for spotting that one - I have since edited the post.

To all - In my last post - to any who noticed - the wording should have been "I never use the Collective etc etc " - NOT cyclic.

It must have been a "senior moment" due the late hour I replied!

As an aside Hillerbee - did I note that You are flying a 12C?

Tc
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Postby Hillerbee » Wed Mar 29, 2006 9:03 pm

Yes, I'm flying the C's
Hillerbee
 

C model

Postby tcamiga » Thu Mar 30, 2006 8:27 am

Hillerbee wrote:Yes, I'm flying the C's


Hi Hillerbee

I never flew a C as the E was just replacing them. I remember seeing the last one in the company tied down to the ground while the Franklin engine was being run in.

The pilots spoke well of them with the Franklin blowing the occasional pot and keeping both blades in the rain as their main probs in Kiwiland.

How about some info such as pilot notes or handling details?

TC
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Postby Plumberpilot » Thu Mar 30, 2006 2:00 pm

Hate to keep asking but I'm just trying to get it right. I use the carb air temp guage to monitor carb temps. I keep the temp in the green at all times clear or cloudy conditions. I'm still unable to find anywhere (except here) the recommendation to use full carb heat before lowering manifold pressure as discussed. Do you not trust the carb air temp guage? Maybe the C dosen't have a carb air temp guage. All I can find both in engine operating instructions and POH is to keep air temp in the green if a guage is installed.

Thanks
Ricky
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