RAF Prop/Engine/Supertrap noise

[lanichol]

The noise heard on the ground as a gyro passes over is a combination of the prop and engine noise (rpm & muffler) together. I found a recent video of a UFO and noticed the noise seemed to be mostly prop. I don't know what muffler they use and I suspect the cowling smooths out the air and noise.

I own an AAI mod RAF with supertraps and an IVO adjustable prop. The noise in my opinion from the ground is unreasonably loud. After flying with Ron M in AR, I think the old RAF single muffler had merit.

Does anyone have suggestions on getting the noise down.

UFO link *Note the noise level.

http://www.youtube.com/watch?v=XGSCe1upK68&mode=related&search=

[Ronnie L]

Larry

My RAF 2000 is fitted with a 2.37:1 Re drive instead of the 2.1:1 which is normally fitted.
The noise is greatly reduced.
People come over and ask why my gyro is so quiet.
It really makes the difference.

Ronnie L
RAF2000 with stab
G-BYIN

[lanichol]

Larry

My RAF 2000 is fitted with a 2.37:1 Re drive instead of the 2.1:1 which is normally fitted.
The noise is greatly reduced.
People come over and ask why my gyro is so quiet.
It really makes the difference.

Ronnie L
RAF2000 with stab
G-BYIN

Ronnie,

I'll bet it does make a different. Could you expand on your setup? The 2.37:1 on a RAF is new to me.

Are you running the Sub 2.2 and the RAF prerotator? How about the exhaust system & prop?

FYI, I have a hydraulic pre-rotator clutch which might be of interest. You had asked in another post a few months ago about a better solution to engauge the clutch tighter.

[Ronnie L]

Larry

My set up is 2.2 carbed Subaru, RAF ignition, standard RAF exhaust, 68 four blade warp driveand standard pre rotator.
The 2.37:1 Redrive is something Aussie Paul was using. I asked RAF when I was ordering my kit and they sent me one. I was told it was ten percent less powerfull, but I haven't found that.
Your pre rotator set up would be very interesting. What RRPM do you get before moving. Please would you post some pics.
I'm away for five days now and may not be able to see the forum.
Looking forward to seeing your set up.

Thanks
Ronnie
RAF 2000 with stab
G-BYIN

[lanichol]

Larry
Your pre rotator set up would be very interesting. What RRPM do you get before moving. Please would you post some pics.
I'm away for five days now and may not be able to see the forum.
Looking forward to seeing your set up.

Thanks
Ronnie
RAF 2000 with stab
G-BYIN

There has been several post on the system. It originally was built by KenSandyeggo.

http://www.rotaryforum.com/forum/showthread.php?t=3542&highlight=prerotator

[Ronnie L]

Larry

Have you found this to be a big improvment?

Ronnie

[lanichol]

Larry

Have you found this to be a big improvment?

Ronnie

Ken at the time he built the hydraulic pre-rotar offer to sell it as a kit. There is no way you can have the leverage or control with a cable as compared to a hydraulic setup. I am surprised that more people have not followed his mod.

Larry