Advantages of RTR?

[Real_McCoy]

Why is Rotors Turning Refuelling used?

[Fg Off Max Stout]

Shutting down the aircraft and then restarting it will significantly increase the time taken to complete the refuelling. Depending on type, you might be looking at 5-10 mins of refuelling against 30 mins shutting down and starting up. Also, with rotors running, you have the ability of departing in a hurry if necessary - use your imagination why!

[Double Zero]

For similar reasons, the Harrier 2 ( Gr 5,7,9 etc ) can ' hot refuel ' with the Pegasus running.

In early days a Test Pilot caused a little consternation when he requested a hot refuel in a Sea Harrier, having just spent a lot of time on the GR 5 - the refuelling point on Harrier 1's is between the nozzles, not forward of the port cold nozzle as on the Mk 2 !

To the West Freugh refueller's credit, he did momentarily consider giving it a try, no doubt thinking we southerners weren't so soft after all...

[Tourist]

More importantly, Helicopters tend to break down if you stop or start them.
Start one in the morning, and it will probably remain serviceable all day if you just keep changing the crew rotors running along with the fuel.

[airborne_artist]

In a maritime environment it may be neccesary to consider the aicraft's wind speed limits for rotor shut down/start. RTR means the aircraft can stay in use if the wind over the deck is already/may become too high. On the S61 it was 50 kts, and I don't remember it becoming an issue when I was in the N Sea oilfields as the deck was static. Different matter if it's moving at 25 kts.

[6Z3]

...and keeping the rotors turning while you HIFR from a fouled (or otherwise blacked) deck, has real flight safety advantages!

[diginagain]

More importantly, Helicopters tend to break down if you stop or start them.


Particularly on Lynx, which on occasion would happily dump the contents of the engine lubrication system on shut-down. If it happened in the field you'd be fortunate if the Techs had loaded enough oil in the BAT-mobile. You soon know if the seals were shot as the oil would fall out the exhaust as fast as you pumped it in at the front end.

Followed by an ECU-change, ground run(s), airtest(s), PPI, etc, etc.

[Double Zero]

It struck me re. oil, from the other angle; hot refueling will only work so many times before engine / lube oil ( and indeed water ) runs out, even if topped up to ferry level in a Harrier's case - at least the OBOGS takes care of oxygen.

However hot refuelling must be handy for a few goes for all the reasons listed by others here !

[diginagain]

From memory, we were limited to 4 hours between dips, due to the rate we went though the stuff.

Got a couple of oily tee shirts round here, somewhere.

[Occasional Aviator]

Another point you may wish to consider is that it sometimes means you don't need as much refuelling kit or real estate. If you're working a force of helicopters hard, the reduced time on the ground means that more can cycle through a couple of refuelling points in a smaller area in a given time. Smaller footprint is better when you want to a) be mobile, b) be protected and c) put as few people at risk as possible.

Yes, oil levels are usually the limiting factor, and when doing continuous operations there is usually a stripped down mandatory servicing/maintenance procedure so that every few hours or so you shut rotors down to check levels / top up. On the more modern types, and those designed for use at sea, this interval can be quite long, up to 16 hours or so.

[Green Flash]

Which begs the question - well, it does after a half a gallon of Atlas - (Three Sisters, as you're asking) is why hasn't someone invented Rotors Running Oil Replen? All other consumables (driver/pax/frieght/bogs/bnag bits/etc) can be changed with the fan on, so why not oil? And while you're at it, hyd too. Ferk me, I'm brilliant I am. Now where's that GEMS form and I'll be rich I tell you, rich! Ha ha ha!!! Hic. :\








Mr Flash has been forcibly removed from this workstation and is now recieving medication. Please continue as normal. Thank you.

[wg13_dummy]

Green Flash, the bowser for the oil would be bigger than the bowser for the fuel for the Lynx. Ignorance is bliss sometimes. :ok:

[minigundiplomat]

When you look at the life of an engine, apu or transmission etc, it makes sense to reduce the number of cycles, thus extending the life- theoretically.

The main points has already been mentioned though, time and the chance that if you shut down, there is the high probability of going U/S.

[The Helpful Stacker]

Ex-wing mong here so no stranger to a Lynx supplied hot oil shower whilst carrying out a refuel whilst said cab is shutting down at R850!
On the benefits of RTR for servicability, at Odious we set up an RTR site for that very reason and it is proving very useful towards improving servicability rates.

[Background Noise]

Everyone seems to be talking about engine life etc - the Q was about rotors running - presumably you can have engine running/rotor stopped?

[WASALOADIE]

The majority of modern choppers have a very low oil usage therefore dont need the oil top ups as frequent. Some time ago in the Chinook (Mk1) we used to do long flights with Andover tanks fitted, prior to flight we used to ensure that oil levels were topped up, and physically move the oil level floats to check the low oil level captions came on. Inside the cabin there used to be connections for a risbridger so that if the low level light came on we could put the contents of a tin in inflight and plan a divert to a base. Seem to remember that the max oil useage rate was 1/2 pint per hour. In all my time I never saw the low level caption come on so never needed to top up, also on checking levels on the ground post flight there was very little used.

A for RRRF, they save a significant amount of time on the ground especially if working near max weight when the requirement is for lots of frequent refuels.

[x213a]

Everyone seems to be talking about engine life etc - the Q was about rotors running - presumably you can have engine running/rotor stopped?


On Lynx you can run No1 on acc drive with rotors stopped.You still have to revert to ground idle in order to obtain main though. Far easier and less time consuming to rrrf.

[Tourist]

Background Noise.
Whilst it is possible to have both engines running with the rotors stopped during start, it is very difficult to stop the rotors with both engines running.

[N Joe]

"When you look at the life of an engine, apu or transmission etc, it makes sense to reduce the number of cycles, thus extending the life- theoretically."

Not necessarily true. A disproportionate amount of engine wear occurs in the period after start due to cold lubricants and the thermal shock due to rapid heating. Therefore, shutting down for a short period can cause more wear than leaving the engine running. Of course, the simplistic lifing of some components on engine running hours throws a spanner in the nicely warmed-up cogs of my argument.

N Joe

[Tourist]

N Joe
I think that is exactly what the bit you quoted meant?:confused:

[minigundiplomat]

Thanks Tourist,

I thought it was just me for a moment.

[Occasional Aviator]

Me too.

Also, for completeness, the UK variant of the Puma has no accessory drive - therefore rotors can only be stopped if both engines are shut down. This also means that you (effectively) have DC power only and not all your radios will work - so if you're waiting for a call on the tac net it isn't a good plan. Clearly you wouldn't transmit during refuel in any case.

On the Merlin, there is the option of shutting down to one engine with rotors stopped. This leaves you with all the services you might require (electrical, hydraulics), and gets around the running-time limits on the APU. It also means that you can crew-change more easily (no need for stick-holds etc) and it uses much less fuel than running 3 engines.

[Gerontocrat]

I'm sure the good folk at Benson can tell you how good their RTR rep is ...


Oh, I see!


Taxi!

[x213a]

Didnt Puma used to have a clutch system fitted?

[N Joe]

MGD

You are quite right in what you say; my point was aimed at the simplistic lifing policy of many multi-million pound aircraft (when my much cheaper car knows how it has been driven and adjusts the required service interval accordingly). No offence intended.

N Joe

[x10ge]

Or maybe it just stops the F700 from being filled in, a lot less snags that way! No I'm not a cynic just a realist.

As for replenishing the oil on a running engine - forget it - its hot, noisy and usually puts the FOD hazard up. I have seen a long lead disappear up an intake (mind you it was an early generation chopper but it did have Gnomes).