Robinson R22 Corner [Archive copy]

[the coyote]

R44 Doors off Vne

I have heard that the 100 Kts doors off Vne in the R44 is not an aerodynamic limitation but to minimise the risk of injury to passengers sticking their arms outside.

[3top]

hi dog - aah coyote:

you heard right, the 100kt doors off limit was suggested by a nonflying company engineer, that figured, if you stick your arm out into the slipstream, it might get you some rather painful modifications to your elbow and/or shoulder joint locations, if you do not do so with some pretesion applied to your arm.

I have it from a guy who knows Rīs insight out, that it is NO problem and bears no safety-riscs in terms of aerodynamics or structural integrity, if you push past this limit.
HOWEVER keep in mind the original intention of the engineer.
Plus it getīs pretty windy in the back if you push it, also lose objects are a concern with doors off, more so at high speed.

Interestingly, the R-22 has no doors off limit, other then Vne - 102 kts - I guess the R-22 is just safer at 102 then the R-44 at 100 kts, as you are already half out in the slipstream from the start!!
3top

[[email protected]]

3top, if you want to get down quick then just roll inverted and pull, it always worked well in the Lynx!!! Seriously you must ask why you would want to fly at 100 kts in auto as any increase in speed above the recommended auto speed for min RoD brings with it an increase in RoD - at 100 kts in a robbie your RoD would be very impressive and would probably not take you as far as if you were at 75 kts and 90%Nr.

[3top]

Hi crab,

IīD LOVE THE ROLL OVER AND PULL, but my R-44 doesnīt want, would you borrow me your LYNX???

You are right about RoD, this also holds true for increased Rrpm during auto. Some people (and instructors) teach a higher Rrpm to "have more inertia" when itīs time to flare. However you will need the additional inertia to slow your way increased RoD......
I teach them to stay at about 100% Rrpm, but practise, practise,practise and when your done, practise some more.
You shouldnīt feel good in the evening, if you had a chance to practise an auto or two and didnīt take it!!

However sometimes you just want to go down fast, without the need of an auto termination, as I metioned:

thousands/cloud, plenty of clouds: Turkey Vultures and/or Swanson Hawks migrating on their way to S-America or back to the U.S. of A.

One shouldnīt, but sometimes just gets caught. As long as I have a clear view down I prefer a quick decent to about 50-100 above the beach, than try to hover around OGE with thousands of ornithopters!!

The closest I ever saw a Lynx was on a tunaboat in the caribian, and a Royal Dutch navy helo payed a visit, hovering along sideways at bridge hight (about 20 ft) at about 12 kts. Besides the awkward looking wheels it is a nice ship!!


3top

[headsethair]

Don't want to cause any confusion - but I was told that the R44 limit was for entering autorotation. Apparently if you enter auto over 100 kts there's an aerodynamic certainty that the tailplane will kick you into a nosedown dive......same does not apply to R22. And, BTW, new Raven II announced with US price $35,000 more than Raven I. Uprated motor, 24v lx, higher HOGE, higher GW, higher max power takeoff - and a lighter wallet. Still no fuel injection and no sign of a diesel!

[3top]

Hi headset,

there is no speed limit to enter an auto. You enter whenever you HAVE to at ANY speed you have to. Vne power off is for the established auto. What are you going to do, when engine quits at 120 kts cruise? Slightly flair while lowering the collective - you will go horizontal quite a bit until getting to the recommended speed and establishing the correct descend.
If you enter a auto at or above 100 kts you might get into low "g", IF YOU DONīT DO THE RIGHT THING: Holding the nose up with slight aft cyclic!! .....while you lower the collective gently to avoid rpm decay or overspeed!!

Raven II has fuel injection, but not electronic. Max take off power, donīt know yet, max continous I understand is the same.

higher altidudes due to higher hp rating of the engine versus th e old one (260 - 280), so it can maintain specified 225 to a higher altidude. max gross increased by 100 lbs.

I let you know anything you want, when I got my eyes in close prox. and my hands on the controls, when our new ship shows up, sometimes in October, ! ! !!!

3top

[3top]

Hi again,

this afternoon I went over the POH of the R-22 with my student:

Turns out the R-22 has a Power-Off Vne after all!!

However it has one only when equipped with floats (Mariner):

Vne - power on: 95 kts
Vne - power -off: 85 kts

or according to the placard for speedlimits at altitude!

3top

[Robino]

R-22 lease back prices

Anyone know whats the current price per Hr for the leaseback of a R-22 in the UK.
Any other info on this subject would be very helpful.

Thank you

Robino

[misterbonkers]

it really does depend on the age of machine, condition, who's hangaring it, insuring it, whether its a wet or dry lease, how many hours they are going to fly etc. If you can be more specific I will try and help.

Insured by you on a dry lease of say 25 hours/month you'd be looking to get from Ģ75-85/hr depending on the machine.

[Helinut]

In the UK, the rates seem to vary a bit, depending upon where you are - not sure why; perhaps supply and demand.

I am no longer in the R22 training game, but I get the impression that there is a bit of a shortage of R22s (and other simple, small helicopters) for training lease - Can anyone confirm?

[cyclic flare]

There is a large shortage of R22's in the north west. (or a shortage of people willing to let them to the flying schools to wreck them)

If you are prepared to let a school use them i know schools that will pay Ģ115.00 + vat wet per hour

[headsethair]

In the south there's a shortage of R22s for training - I keep being asked to buy one to put on the fleet for my operator. But the leaseback rate won't go above Ģ90/hr. Sure - the machine will work 200-400 hrs pa but I can only see Ģ15/hr profit in my figures. (And I would have to pre-book private use by some notice because of the workload.)
Better rates for R44 (Ģ150/hr) - but less demand.

[Jiff]

R22 Governor improvements

I have just finished putting together an improved governor for an R22, it works in much the same way as the original governor but it is load sensitive, i.e. it monitors the position of the collective and changes the PID values in the primary feed back loop as required.
The result is a governor that responds a lot faster and is more accurate, This system is yet to be flown but I have done some extensive bench testing using data collected during ground runs and routine flights.
The platform which this is based on uses a dedicated micro processor and has nothing to do with Mr. Gates (probably going to be reliable), it has a great deal of additional capacity and there is no reason, with the addition of a few extra sensors, (technically) why additional features can not be written into the software i.e. engine monitoring (fadec) and power checking.

What I am really looking for is some advice.

1. Is there anyone who may be interested in pursuing this?
2. Is there a market for this type of technology?
3. What does the certification process involve?


Regards
Jiff

[The Nr Fairy]

As long as it can stop overspeeds, I'm all for improvements !

[Dave Jackson]

Jiff,

A couple of things.
__________________________

1/
You may be interested in the following posting from rec.aviation.rotorcraft, dated September 25, 2002

"I am building a Safari (Baby Belle) helicopter here in New Zealand.
Also, I have written a detailed document on how to convert the Robinson R22 Governor for use in the Safari helicopter. This MS-Word document, including detailed pics of the control board and modifications, can be downloaded at: http://www.bart.gen.nz/safari/governor.doc

And last, you can reach me personally by email on:
safari (at) bart.gen.nz (To stop spam.. Please replace (at) with @ "
___________________________

2/
In response to your questions, I am definitely interested in your governor controller. My two helicopter projects entail the use of a governor; preferably a rotor governor, or a combination rotor/engine governor. A couple of pages on my web site, which may be of interest, are; http://www.synchrolite.com/Governor.html and the more esoteric http://www.unicopter.com/0575.html.

The UniCopter is being designed for a small 4-cylinder Lycoming, similar to those used in the Robinson R-22.

The SynchroLite is the basis for looking at the possibility of producing certified blades and a certified collective device. These two components can then be used by others to build twin-rotor helicopters. These twin-rotor helicopters could be coaxial, intermeshing, interleaving or side-by-side. The symmetrical configuration combined with a governor (for automatic entry into autorotation etc.) should greatly increase the safety of very light helicopters.

The very light helicopter consideration is to produce RH & LH asymmetrical blades where four of them can support gross weights between 500 and 700 pounds. This will allow them to be directed at the US Ultralight (no license required), the US Experimental, and perhaps eventually at the US Sport Plilot/Aircraft and the European JAR-VLR categories.


Dave J.
[email protected]

[vorticey]

jiff

i think it would be handy on mustering machines, the govenors always overridden on them, although i cant see anybody spending money to upgrade when its probably not as fast as the trained wrist.

[vorticey]

R22 power drain

I've been thinking about the neoprene tailrotor delta hing bush that is an up grade on the R22 helicopter, it seems to hinder flapping of the delta hing.
I recon that in forward flight, flapback of the tail rotor would be reduced, therefore increasing the amount of power used for antitorque and fuel consumption.
any thoughts?

[CRAN]

Theoretically your concerns are correct, but don't worry about it the resistance offered by the bearing is negligable in comparison to the aerodynamic moments generated. Therefore, there will be virtually no difference in the flapping characteristics of the orginal metal bearing and the new elastomeric device. Correspondingly, the power differences will also be negliable.

CRAN

[Dave Jackson]

Related trivia

One of the Bells had an elastomeric or spring on its main rotor teetering axis. The objective was to reduce out-of-plane motions when the disk was unloaded, and/or, to give the craft a slightly faster response to cyclic inputs.

Additional information on this can be found at Rotor - Hub - Hub Spring

Dave J.

To significantly reduce the power drain, eliminate the whole tail rotor.

[Shawn Coyle]

Jiff:
An interesting project, but a couple of pointers.
You will need to do some pretty detailed testing of the system, from hardware to software to get this approved by the necessary authority as an STC.
Also, you'll need to show some sort of benefit to the end user in order to convince them to purchase it.
Not going to be cheap or easy to do either of those.
Have you done a business case on this?

Some other thoughts- how about for homebuilt helicopters? Can you modify this for any other engine? Might be more of a market than for R-22?
The real issue I think for the R-22 market is that of insurance. Can you still get Robinson to issue insurance for a modified machine like this?
Have you checked with Robinson to see what they say? They might be interested in taking it on.
Not wishing to rain on your parade, but the hard realities sometime need to be faced.