Increasing Cruise speed for a RAF

[Hoges]

When my RAF cruises at 75 kts indicated (actual about 67kts by GPS) I have to hold the stick forward to maintain airspeed and need to hold constant left rudder to keep her straight. Mast is in position 4 (rotor head most rearward, I think). Doors off btw.
I have a large HS fitted, 2.2 soobie with 2.37:1 redrive, 68" Ivoprop Magnum (works great), otherwise standard.
The hang test allows me to use mast position 2 or 3 if necessary.
Darn ELA's were leaving me behind today with their 8 to 10 kt cruise advantage.
Any tips to increase cruise speed appreciated.
Scott
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BUY NO2 VAPORIZER

 

[Murray Barker]

Dragon Wing rotors and a tall tail.

 

[Greg Mitchell]

If Ernie has a problem with DW's on Golden's then the same could be said of the Raf2000, same AUW.

Mitch.

 

[C. Beaty]

Have you considered dimples?

This site gives a good explanation of why your RAF is so draggy:

http://www.aerospaceweb.org/question/aerodynamics/q0215.shtml

 

[Harry_S.]

When my RAF cruises at 75 kts indicated (actual about 67kts by GPS) I have to hold the stick forward to maintain airspeed and need to hold constant left rudder to keep her straight. Mast is in position 4 (rotor head most rearward, I think). Doors off btw.
I have a large HS fitted, 2.2 soobie with 2.37:1 redrive, 68" Ivoprop Magnum (works great), otherwise standard.
The hang test allows me to use mast position 2 or 3 if necessary.
Darn ELA's were leaving me behind today with their 8 to 10 kt cruise advantage.
Any tips to increase cruise speed appreciated.
Scott

Scott,

Cam position 4 is the most "upright/forward" mast/head position.

If you need to hold left rudder, either bend the rudder trim tab or you can add an anti-servo tab like I did on my machine. It works just fine.

What is your rrpm at normal cruise and at your higher speed?


Cheers

 

[Steve Osborne]

Rotor head most rearward is position # 1. If you have installed a h-stab or put any additional weight aft of the radiator you can not use RAF's hang test #s. Start in position 3 and adjust until you get the keel level at 80 mph solo with about 1/2 tank of fuel. Reduce the left trim spring pressure by adding links to the chain. Set the rudder trim tab to feet off at auto rotation speed.

 

[route66]

You might want to start by checking your rotor head and control setup for proper angles. Be sure the Keel is level fore and aft as well as side to side. My first setup was in error as the floor was not as level side to side as I assumed. Moving the c/g position to #3 will give you more nose down and will require adjustments to the Rotor Head and controls upon change. My new-bee guess is you’re just a little out of adjustment and rechecking your rotor head rigging might be a good place to start.

 

[birdy]

Dont wurry Hoges, wen it starts rain'n, them blokes in their open 'bathtubs' will be on the ground as you cruise past.

 

[Hoges]

Hi Birdy,
What is your Ivoprop like in the rain, does the rain damage the blades at all?
I know it doesn't happen all that often (rain that is).
Scott
________
Dodge Monaco

 

[birdy]

Iv been through plenty of rain with that ivo Scott, 4 hours of heavy rain on the way to QLD coupla years back.
They can handle plenty.
The only thing that took a coupla chips outa it was wen i was taken off from a gravely wet road.
The mud/gravel was flung up from the mains, but only did asthetic damage.

 

[Hoges]

Was that with EJ22 or the Rotax?
I wondered how the EJ would go (or stop) in the rain with no cowling over it.
Scott
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Toyota Brevis

 

[Gyropilot007]

Scott:

I've been "caught" in the rain with my EJ2.5 FI and had no problems whatsoever with it.

Bob

 

[birdy]

I did 'wash' the wasa a coupla times wen it had the ej22 [ carbed] and cept for the ice before i pull heat on, it was orrite, but it wasnt heavy rain.
I only had the ivo on the 914, had the WD on the ej.
Rain shouldnt wurry either engine solong as you have carb heat protection.

 

[C. Beaty]

I imagine a fin such as the one on top of a Hughes 269 cabin would produce a significant increase of cruise speed.

The intent appears to be keeping the flow attached longer and reduce the size of the vortex aft of the cabin.

 

[helipaddy]

I believe the 300 had unpleasant pitch stability issues in cruise flight without the thing on top of the cabin fitted

 

[C. Beaty]

I believe the 300 had unpleasant pitch stability issues in cruise flight without the thing on top of the cabin fitted

Might also help an RAF in that regard. Vortices are always unstable as evidenced by an RAF in the yaw axis with doors fitted.

 

[Hoges]

Birdy, Chuck and All,
I can actually get a good cruise speed of about 70 kts but have to hold the stick forward all the time as I run out of trim adjustment. After talking to a good mate of mine, he suggested that a 10kg weight or thereabouts fitted to the most forward position of the aircraft keel would help counter the forward stick 'holding' pressure as they found this worked well on a Sparrowhawk that similar problems.
The alternative would be an adjustable trim spring on front of the mast to add trim in the opposite direction to the fitted trim and could be a complicated solution.
Birdy,
I have an EFI EJ22, no carby, so no carby heat. Should fly in torrential rain, right? R u going to Nationals this Easter?
Scott
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Headshops

 

[birdy]

Wot nose down angle is the HS set at Hoges?
The higher your AS, the more down force the stab will be prodceing, pushn the nose up.

You can still get iceing ina EFI setup, coz of the butterfly valve, but less likely than a carbed machine.

Dont look like ill be gettn to Wang this year mate, next time maybe.

 

[Hoges]

Hi Birdy,
Maybe I just need a trimmable HS? I think the removable weight system is very simple though.
From memory, the HS is in line with keel.
Paul Bruty told me some time ago that the objective is to get the keel level at cruise, so I have my angle measuring device stuck to the inside of the cabin in a visible place to check angle of dangle.
I guess the extra air speed causes drag on the rotor system to increase (here we go) and causes nose up.
Scott
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Daihatsu move history