If the wind is from forward-left as you describe, the the blade advancing from the right side will reach maximum upflap at the 1 - 2 o'clock point, the retreating blade will reach maximum downflap at the 7 - 8 o'clock position. The tailboom is at the 6 o'clock position. You do the math

Agreed. That description is 180 degrees out. Have the wind in your back right hand jeans pocket with your wallet is how I remember it.

"limit is 26Kts i think"
Better keep them out of the Grand Canyon. 26kts is a nice day......

When we first got R22's many years ago, we asked Robinsons for the reasons for the 26 kt bit for starting and stopping. Answer - the CAA said there had to be a reference in the Flight Manual so we said oh, er, ok, 30 mph. When we conducted some trials, we found the R22 was more resistant to blade sailing by a long way than other types and with better tailboom clearance in gusts. Whether you want to train in wind speeds much above 25 kt at ground level is another matter.

Composite blades and the R22
 

Just a question I would like to ask.With the previous blade problems,and the new bonding problems arising in the dash 4's.Could,or would a composite blade be a better option for the R22?It could extend blade times,and solve the structural integrity of such a small blade!

Yes but it would mean a huge price increase in a new set of blades, which would eventully have to be passed on to the customer, making hire rates more expensive.

The Robinson does a good job in its Current format in allowing the pleasure of flying to more and more common folk. An increase in prices would make that gap increase and stop more people taking up flying.

R22.

True!They would be more expensive in the first place.But the timex would probably at least double,possibly triple.That is a huge saving at O/H.I am no tech guru, just a jockey.What is the life span of say a squirrel blade?

I agree that over a long term they would probably work out more cost effective but the initial outlay would put off alot of people and also the abuse they get in large training schools would make them and expensive nicety.

Just recently at our school, one of the R22's had new blades fitted and then after 100 hours of use, a line service guy twatted one as he was pushing the heli out of the hanger!

Expensive mistake, even more expensive if they were composite!

I don't thing that a composite blade is necessarily more expensive. A lot of the blade's cost will depend on the production rates over which the fixed costs can be amortized and the automation or mechanization of the variable costs.

A decrease of new craft sales, or a longer blade life, or the eventual end of R-22 production have probably been considered by Robinson when evaluating this option.

20,000 hrs for the squirrel blades i think. Do you have to be common to fly a Robinson ?:E

How do the weights of composite vs aluminum work out for rotor blades? I imagine since rotor weight/inertia is fixed by auto response time, the only advantage is extended fatigue life from lower root stresses. Initial tooling would favour composite, but i imagine the R22 jigs are long since payed off.

Dave, how is your blade work progressing? It looked like you were making great progress, so i'd like to follow up.

Mart

Not so much common, just skint!! Like me!!!

Most Robbies are shake-rattle-and roll. Some of them could shake your fillings right out.

But it doesn't have to be that way. The one I flew today was sm-o-o-o-o-th. I mean really, it could have been a three-bladed system.

Which gets me to thinking - how much of the problems are caused by poor set-up. Stands to reason that a machine with poor tracking and high vibration levels is going to suffer more wear and tear than one that's all set up and smooth.

Perhaps that's the answer - a well set-up machine is much less likely to shake itself to bits. Question is, how achievable is it ? Some machines just seem harder to keep in track and balance than others.

Graviman,The composite blade is lighter, while at the same time the profile can be improved, and the rotational inertia can be maintained or improved by adding back a little of the weight at the very tip of the blade.

Ref. Sikorsky S-61 blades; http://www.ainonline.com/Publication...endingpg2.html

Currently debugging the controller. Then to build the frame and mount the hardware. It's not as much fun as Aerodynamics.

Dave

Lock nuts and overspeeds
 

Pre flighted the club 22 today and when i got to the cooling fan the locking wire was not in line with the painted lines (a good 30% out).

Didn't fly it and reported to the engineers who said that when you take off the cooling fan for maintenance it doesn't always line back up again and that they didn't repaint the line as the a/c was only a few hours of its 100 hour check.

I have to say i have a few problems with this answer, but as a 100 hr newbie (aka know nothing) and a non engineer I don't want to make a prat of myself.

Would welcome the pprune collective wealth of experience, specifically;

1. Is a misaligned nut always a sign of an engine overspeed or does their explanation have merit.
2. If their explanation has merit then if the nut is put back on to the prescribed torque values then why doesn't it line up.
3. Can the nut slip without the wire breaking (this was also given as a reason why my concerns were unfounded).

Suffice to say that at present I am avoiding this a/c like the plague :eek:

thanks in advance

Mr R Biggles

Mag check may be cause
 

Mr Biggles,

The fan is on a tapered shaft.

If a pilot (student?), turns off both mags during the pre flight runup check, then human nature is that we immediately flick it back on ....... the engine almost stops and then bursts back to life.

A great stress is placed on the fan and it can slip on the shaft, so misaligned marks can mean a fan which has moved.

Can anyone else help here?

Find a new Engineer !

E

I would want to know what maintenance was being carried out and why it was being done out of sequence. If there was there something wrong with the machine that couldn't wait a few hours, I think you should be told !

(How long does it take to repaint the line anyway?)

Pre-flight checklist says it should be in line because that's how you know if there's been an engine start with throttle open or other problem. It's a safety feature leaving a tell-tale if a problem has occurred.

Letting it go from maintenance without lining up and repainting the marks precludes the pilot from knowing if such a problem has occurred.

I'm picky, but I would absolutely refuse to fly an R22 without the nut and marks in line. If I was the owner (and I do own one), I would also consider moving the a/c's maintenance unless I got a very good answer as to why an engineer would release the a/c to service with this safety feature effectively disabled - from a non-engineer's viewpoint, it gives an impression that the person did not do a full and complete job - so what else was not done fully and completely?

BW

All good advice thanks.

The "marks don't always line up after the fan has been off" argument that was given by the engineers just seems wrong.

Interesting point from BW, but I had always assumed the thread and nut will always start at the same position of the thread when it first "lines up". Thus if it is always set to the same torque value with the wench it will always end up in the same place.. i.e in line with the white marks. Maybe i'm missing something here.

If true then any deviation must mean slippage hence some sort of overspeed, mag jolt, overtourque etc (all bad regardless of the original issue).

I have joined a syndicate which has different engineering (of the reasuringly picky kind..) but it does make you think given that Uncle Frank (not a man to waste words or pages in the POH) makes it part of the checklist