RNZAF P-3K/P-3K2 Orion

[deaneb]

QUOTE (Ian Warren @ Jul 13 2012,9:49 AM) <{POST_SNAPBACK}>

Looks hes had his starboard props maintained recently , wonder why one side only ? .

Different parts of the aircraft are maintained on different cycles. The props and engines on one side have minor maintenance on a regular basis (about 400 hrs) and it alternates from side to side along with parts of the fuselage and wings. On top of that each prop and engine has its own hours based overhaul cycle (as do hundreds of other fitted parts). The hours each part has flown will be all different depending on how long since they were fitted.

[A185F]

Dean any idea why the Orion has round tip blades vs the Herc and Electra with square tip ?

[Ian Warren]

QUOTE (deaneb @ Jul 13 2012,10:51 PM) <{POST_SNAPBACK}>

Different parts of the aircraft are maintained on different cycles. The props and engines on one side have minor maintenance on a regular basis (about 400 hrs) and it alternates from side to side along with parts of the fuselage and wings. On top of that each prop and engine has its own hours based overhaul cycle (as do hundreds of other fitted parts). The hours each part has flown will be all different depending on how long since they were fitted.

Cheers Dean , that covers the missing paint

[Ian Warren]

QUOTE (A185F @ Jul 13 2012,11:16 PM) <{POST_SNAPBACK}>

Dean any idea why the Orion has round tip blades vs the Herc and Electra with square tip ?

I could possibly answer this question , its all due to the residual and sound effect on the structure , when the L188 was was introduced back in 1959 , they had all sorts of structure problems hence even the first RNZAF aircraft even had to be returned , a few Electra's fell out of the sky due to the problem , this is why Mil/Civil Aircraft are a little different .

[HamiltonWest]

June 2012

[HamiltonWest]

[HamiltonWest]

[deaneb]

QUOTE (A185F @ Jul 13 2012,10:16 PM) <{POST_SNAPBACK}>

Dean any idea why the Orion has round tip blades vs the Herc and Electra with square tip ?

I've heard all sorts of reasons over the years, but the main one seems to be due to efficiency and avoiding issues with compressibility with the higher cruise speed of the Orion. The square tips of the Hercules blades give better performance for take-off and at lower speeds. Noting that the RPM of Herc and Orion props is exactly the same at 1020 RPM (100%) - always. The only exception is on the ground where the engines can be switched to a ground range which takes the RPM down to about 72%.

Ian is right - there is resonance which has an effect on the fuselage (and the occupants). If you have ever flown in a twin engine plane where the props are out of synch and drone, you will know what I mean. I'm not sure if the square ends has much effect as both Herc and Orions use the same method to overcome resonance. The resonance problem is overcome in two ways:

1. Sychronising RPM - all four props need to be doing the same RPM.

2. Syncrophasing - With each prop travelling at the same speed, you need to ensure that the prop tips of the baldes of a prop never pass the tip of the adjacent prop blade at their closest point. This is done by electronically trimming the speed subtely (up or down) so the blades are slightly different places in their circle of travel at any given point in time. In other words if you look at one of Ham Wests photos, you can see that no two props have blades at the same angle respective to each other. (But be wary of ground shots as the system does not work in the lower speed ground range). Once they are in this position the control system constantly trims RPM (by varying the blade pitch) to keep them "on speed" and at the differing phase angles.

[HamiltonWest]

[Ian Warren]

QUOTE (deaneb @ Jul 31 2012,8:29 PM) <{POST_SNAPBACK}>

2. Syncrophasing - With each prop travelling at the same speed, you need to ensure that the prop tips of the baldes of a prop never pass the tip of the adjacent prop blade at their closest point. This is done by electronically trimming the speed subtely (up or down) so the blades are slightly different places in their circle of travel at any given point in time. In other words if you look at one of Ham Wests photos, you can see that no two props have blades at the same angle respective to each other. (But be wary of ground shots as the system does not work in the lower speed ground range). Once they are in this position the control system constantly trims RPM (by varying the blade pitch) to keep them "on speed" and at the differing phase angles.

That's why we have you on board , the technical department

[deaneb]

QUOTE (Ian Warren @ Jul 31 2012,9:07 PM) <{POST_SNAPBACK}>

That's why we have you on board , the technical department

Comes from 8 years of working on Orion and Hercules Engine and Props!!

[Ian Warren]

Hope ya teaching Greg how to draw em properly ... umm he prob dose that thru school lessons ... prob you did to ... chip of the ole block

[Splitpin]

awesome as always Ham

[HamiltonWest]

Marty

[HamiltonWest]

[Ian Warren]

Mumbubajubba .. those things stick to Hamilton like its there forward operations base in the case Wobblyville gets attacked !

[HamiltonWest]

[Ian Warren]

Not bad for a good 50 year old airframe .. now when can i get to drive her ... least have a ride in one .

[HamiltonWest]

Early 2012

[Ian Warren]

be interesting to when may look at replacing the Orion only a couple years before the 50 mark