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View Full Version : helicopters and sand...risk??


Sam Rutherford
16th Nov 2010, 12:55
Dear All,

Anyone have experience of flying an R44 in sandy conditions? Or indeed any helicopter?

Would be interested to hear about increased wear of blades etc.

Safe flights, Sam.

spinwing
16th Nov 2010, 13:28
Mmmm ...

Wear would be extreme ... really to be avoided if possible ...

The actual wear is hard to determine and of course is dependent on the abrasiveness of the sand ...

Do keep a very careful eye on the blade leading edges .... I have seen H500/300 blades open up with frightening effect ...

Think carefully about using blade abrasion tapes .... they can be more trouble then they are worth ... BUT can if monitored well can save you the cost of new blade sets.

If flying into areas where "brownouts" may be possible .... get some instruction in landings and takeoffs in those type of conditions .... they are VERY tricky and disaster is not far away if you are not totally prepared and know what to do ...

Good luck .... :E

Heliringer
16th Nov 2010, 13:44
Use blade tape if you want to save your R44 blades. Quick landings (no 3ft hover) just keep it moving all the way to the ground and quickish take offs moving forward as you lift is the way to go IMHO.
I found that without using blade tape the paint would be off the leading edge and back behind the bond line after about 50 or so dusty landings, not good.

delta3
16th Nov 2010, 16:46
Sand gets everywhere...

One interesting case I discovered when the low RPM light came up unexpectedly:

The governor clutch behind the left seat can eat too much sand.
In that case it gets sticky and doesn't work correctly (needs manual help)

d3

r44guy
16th Nov 2010, 17:55
I don't have much experience with sand in the R44, but a lot of dry dusty environments.
With over 500 hours on the helicopter, the effect has been negligible so far as I can tell. The dust does get everywhere, but I wash the helicopter very frequently. The blades get very dirty very quick and it hurts performance. Paint is wearing off of the leading edges of the main rotor, but it doesn't seem to be any more than typical with a Robinson blade.

Get some practice with brown-outs with someone who has experience, I deal with it on a regular basis. Like spinwing mentioned, no-hover landings are essential. Quick pickups as well, but you have to be smooth and clear your area/skids carefully. It is best if you can keep just ahead of ETL and make a quick/smooth touchdown, but that isn't always practical or safe, and inevitably you are going to end up in a brown out condition anyway.

I would share my methods on dealing with brown outs, but everyone has different techniques and I don't feel like starting that argument.

I haven't tried blade tape myself, so I cannot comment on that.

R22Million
17th Nov 2010, 00:54
I thought Frank prohibited blade tape on the tail rotors (not sure about the Main set)

Also, wanted to just restate the obvious for any one that might not know..

If you find that the paint has worn back behind the bond line on the R44 Main Blades... dont be tempted to fly the machine until you have repainted and recovered that bond line.. they can delaminate very quickly .. 3 revolutions .. i was told..

I was guilty of flying a machine back to my Engineer with the bond line exposed and got (quite righty) something of an ear bashing. So if you find yourself in a spot that has no suitable paint?? Use what ever you can find... (my engineer was happy for me to use plain old house paint to cover the bond line the next time i found myself in the same position)

PPRuNeUser0179
19th Sep 2012, 09:40
Hi guys

Does anyone know the risks of landing on a beach?Both on damp sand and "dry" sand.There is this very isolated and quiet beach on the coast in Kenton (little beachy village in the Eastern Cape in South Africa) that I would like to visit in a R22 sometime next year but there are a few things that concern me.

1.)How much sand will be blown into the engine cowling and inlets?
2.)Is there a higher risk of engine failure
3.)I dont assume that the sand will scratch the body with the force of the downwash.(please correct me if I may be wrong.)
4.)what other dangers pose a risk to landing on a beach?

This is an EXTREMELY quiet beach that normally only has 3 people visit it per day (Not a lot of people know about it.)
Also,could someone please give me useful tips when landing on a beach.
Thanks alot

Daniele

Fareastdriver
19th Sep 2012, 10:13
There is no problem if you are careful.

(1) Minimise the time in the hover and very little or none will be blown into the intakes. Ponce about for a couple of minutes looking for a pretty spot to land will instigate recirculation through the rotor. You don't have to rush it, just be sure of where you are going to land before you get there.

(2) No.

(3) See (1).

(4) Avoid landing on wet sand. The residual salt will corrode the bottom of the skids over time. More importantly, if the engine fails to start the tide will come in and drown it.

Enjoy the beach.

stilllearning
19th Sep 2012, 20:30
Having flown in Dakar Rally tought me a couple of things about sand:
Better get anti abrassion tapes
Sand will get anywhere you helicopter
As said before: don't hover around ..
Worst thing: to land/fly low over dunes when sun is up and no shadows available to give you a clue on ground references .... very similar to a white out when flying snow+coverd ceiling.
Nice flights:)

Brilliant Stuff
20th Sep 2012, 09:43
I would have thought just one landing won't harm the machine and you don't need to worry about blade tape.

Make it a slow touch down though in order to make sure the skids are not sinking into any holes.

blakmax
20th Sep 2012, 11:16
R22Million

If your engineer gave you a hard time about paint erosion, he probably has a fixation based on the AD's about paint erosion and "delamination". (The correct term is in fact "disbonding".)

This is bovine excrement "bull****".

I am an expert in adhesive bond failure forensics, and I have examined fourteen R22/R44 blades and found evidence if erosion in only one case. I have seen disbonds well away from the blade tip where on the matching blade there was no evidence of any erosion of the paint.

The critical evidence is this: If the failure of the adhesive results in a layer of adhesive on BOTH surfaces, then it is a bond failure due to failure of the adhesive layer. This would almost certainly be a DESIGN and certification deficiency. The bond was not strong enough to carry the loads and the adhesive material itself failed.

If the failure is at the interface, then there will be no adhesive on some regions of the bond failure. If you see bare metal or a very thin adhesive layer, then it is not a design issue. This is a PROCESS deficency, and there are two causes. 1. There was contamination during the process, or 2. No matter how well the process was undertaken it was a deficient process. Interfacial deficiency can pass usual QA tests, yet fail in service because deficient processes result in hydration of oxide layers on the metal, and the hydration process leads to interfacial disbonding. THIS HAS ABSOLUTELY NOTHING TO DO WITH EROSION OF THE PAINT!!!!!!!! There are documented cases of Rxx interfacial bond failures where the blades were never even fitted, and had zero hours flown, and therefore erosion can not be relevant in these cases. So if bond failures can occur without erosion and after no service at all, why is the theory of erosion the only cause of bond failure? Bovine excrement!

Regards

Blakmax

Agaricus bisporus
20th Sep 2012, 22:45
Blakmax, The correct term is in fact "heifer dust..." ;)

griffothefog
21st Sep 2012, 07:20
daniele,

KNOW YOUR TIDES..:ooh:

victor papa
21st Sep 2012, 15:42
Please make sure you and your engineer know and apply the limits and procedures as stated for that specific helicopter type. They all differ and I know for a fact the EC manuals on the 350 and 130 are now very specific limiting the amount of repairs when and where and how and everything is a repair. More and more problems arising from touch ups and blade tape coming off causing vibration than a ugly looking blade due to a bit of paint missing on a allowable area. A blade expert from EC once said to me dont look at them when they standing still and think they need repair just because the black polyutherane is visible(paint flakes and missing paint allowed acc to manual)-what do they look like at flight idle? We often find problems after a couple of "paint touch ups" due incorrect materials used interfering with the chemicals used by the manufacturer which leads to various problems. Sometimes if the manual states so leave them even if ugly and they will wear to a allowable point and stabilise there-ugly but working perfectly without interference and the composites and protective strips of poly happy. Blakmax, pls correct any statement as I am no composite expert and only knows they are sometimes best left alone to the experts!