RAF aerial views

[StanFoster]

Harry: Thanks...I will post over in your thread. Hey...I have received a lot of information from this forum and also a lot by e-mails from the ones that seldom post here. I am trying to post information that I was scratching all over for as I was deciding to buy my RAF...while I was finishing building it..and while I was learning to fly it.

 

[birdy]

Harry,mate.
The "steed" is an open single seat.
The RAF is two seats, but I only use it if the other one is out of action.[Too big,heavy and slow to throw around.I have used the RAF on cattle before but it's like joy flying in a FA18.]
Most of the work in the RAF is bore runs or quick trips to town.[2 hours]
I'v got some video footage of some mustering[bolted the camera to the machine]and will take it to the easter flyin here,someone maybe able to do something with it.

 

[LARRYEBOYER]

Saturday in Pa was a little breezy. I had turned my blade adjustment 1/2 turn to reduce the pitch.I took off and the rotor blade rpm at cruise was 289. This was an improvement of 15 rpms. I have been flying my RAF with too slow of blades. It took a lot of stick force just to get it to bank.It was not like other RAF's I had flown. At 289, it was alittle better, but still not much improvement. I gave it one full turn on the adjustment screw per side. I took off. At cruise I had 315. It was a difference of night and day. Here is what I gained. The stick force to bank went down to about what is needed to pitch. The airspeed increased 10 mph and the nose flew lower. I cruise at 75 at 4200. The prerotor rpm went up dramatically, and when I turned to taxie off the runway,(my slow blades deterioated very quickly down to 50rpm.) I still had 174! When I would land, there wasn't much energy left when you flaired. After the final adjustment, I landed with lots of blade energy making a feather lite landing. I did several take offs and landings, and all were so much better.It got windier(12-20 gusts. This is where I usually put the machine away. I took off and there were no pitch issues or the tail swaying like it did with the lowerer blade speed. It flew like a new machine. So, thanks Stan for the idea of checking and working with blade speed.My blades had no stick shake at the lower RPM. Now I have a slight shake at the higher RPM. I'll gladly accept the shake for all the piositive benefits of higher RPM. Raf claims the sweet spot is 325. any thoughts on that?

 

[StanFoster]

Larry: I had zero experience as far as what was normal rpm's. Mine were initially 295...and no stick shake. Repeating my story in case someone new is reading...I called RAF and they said it should be 315-325 and suggested a 0.060 inch depitching. So I made me some tracking bars and depitched them. My rpms went up to as what you can read in most of my pictures. 315-325 on average. I have a little stick shake..but not bad. I have been playing with the chord block..taking it one way until it feels worse...then going back to my starting point and going the other way. Presently I have it set at dead center between the towers as measured with my dial indicator. This seems to be the least stick shake. I am next going to try flinging my blades and try that. If that doesnt do it..then I will pick a blade as Aussie Paul suggests and change the pitch a tad.

I will say that now that my 270 pound son is riding along...I can feel more cabin hop..but again..its not bad. But I love fiddling with things and I bet I will get it smoother eventually.

 

[KenSandyEggo]

Stan, fiddling with blades will keep us too busy to ever have to worry about winding up in a rest home or institution. It's a life-long endeavor. I used to get more "cabin-hop" with heavier loads, and now with SportCopter blades, the heavier the passenger, the smoother the ride. It's very good solo, but loaded up it's even better. Go figger.

 

[asmuzsr]

This was brought up before on the old forum, and I'd like to bring it up again. To get your blades to fly smoothly you have to do the following:
1. Weight each blade. They should both be the same weight or very close.
2. Balance each blade. They both have to balance at the exact same spot or your going to have vibrations and those cord blocks will never get rid of them.
(Think about it, if the center of the rotor hub is not in the center of rotation your going to have vibrations because it's spinning out of round. like your clothes drier when it's unbalanced. And if the balance point is different on each blade your center of mass is out and that will cause vibrations.)
3. Install your blades to the hub bar and balance the whole set up.

After this install your blades and track them. Setting the tracking so the tips fly in the same path. Setting the tips so they fly out of track is not how you balance a rotor system.

If your blades come from the manufacture, any manufacture, and they don't weight the same or balance each in the same spot. Send them back and save yourself the headaches cause you'll never get them right yourself. It has to be done when they are built.

tony
N267A

 

[KenSandyEggo]

"After this install your blades and track them. Setting the tracking so the tips fly in the same path. Setting the tips so they fly out of track is not how you balance a rotor system."

Tony, depends who you talk to. Several people that balance gyro blades will tell you that exact tracking is irrelevant. They say that what they are aiming for is equal lift from each blade. If the lift is equal, the blades can be an inch or more out of track and they don't care. They say exact tracking means nothing....that it's the equal lift from each blade that's important.

 

[asmuzsr]

If the blades are manufactured carefully and all those things I mentioned are done the blades will fly the same. If you were to try flying a helicopter setting up the blades as people describe, being out of track, the machine would shake itself apart.

Tony
N267A

 

[KenSandyEggo]

But, not all blades are made carefully, especially most glass blades, and gyros are not helis. To have tracking have any effect, each blade would have to be perfectly identical to the other from root to tip in all ways and their angle would have to be perfectly identical along the whole length. That's practically impossible in a glass blade where foam is squirted into a hollow space on each blade to get them seesaw balanced. This throws off the exactness and they will not fly the same due to weight differentiations along their length. The permanent foam is oftentimes layered in haphazardly with air pockets and thick and thin spots along the way. Blades made like that will never be balanced and give a smooth ride, unless you were extremely lucky and got a set that was paid more attention to during the manufacturing process. I know...I had a set like that. Aluminum blades are much smoother overall, as there is hardly no chance of variations along their length or width. Each spar is the same and the only thing inside is air. That's pretty hard to mess up.

An engineer (and A&P, heli-pilot and Rotorway builder) who balances helis all over the world for a living and works for RADS, couldn't balance my blades over a period of months with some of the best balancing gear available. We got the blades tracking perfectly and it made no difference. As I said, some got lucky with the glass blades. Gary Brewer has glass blades and his own balancing gear. He's worked on them for years trying to get them smooth. His stick shake and "cabin-hop" are horrendous. He just can't get it out and he became a master at tracking them. He had reflectors at each tip and used a mirror in flight to shine sunlight on them and a light at dusk to where he got them perfectly tracked. Again, it didn't mean a thing as far as smoothing out the ride. My guy had a light mounted on the nose of my gyro that shone up at the bottom of the leading blade and measured the track precisely. It was a waste of time making the custom bracket for the light, because the perfect tracking did nothing as far as smoothing out the glass blades. They had too many variations along their length to be "balanceable."

 

[Gordon Gibson]

Gyro's are not heli's

Gyro's are not heli's

Ken, you said "gyro's are not heli's".

Very true of course and powered rotor flight is different to un-powered.
My 500 can be a bit rough in cruise but put her into an auto and...smooth as goose sh*t thru a glass funnel.

Gordon Gibson.

 

[asmuzsr]

Yes Ken your right, blades that are manufactured as you say cannot be balanced because of the inconsistinces in the process. And yes metal blades can be done just as you said. This is why the Sport Copter blades fly so smoothly. I would venture to guess that those blades, each weight the same and balance in the same spot. They have to or your just chasing your tail.

Tony
N267A

 

[StanFoster]

Ken...Tony..or anyone...

Do you know of anyone that has flown a long time with moderate cabin hop...and would this be detrimental to the keel with the tail shaking?

 

[asmuzsr]

Stan
Ken had I think over 400 hours on his ship before it was converted. Probably more. I'm sure there's got to be someone with more. But his was ok and he had a pretty bad vibration.

Tony
N267A

 

[StanFoster]

I was up flying today. This was the windiest day I have ever flown in my RAF. It was right down the runway and talk about fun.



Here are some Deeres out working the soil. I was able to just sit there and my GPS was showing 0 mph.

 

[StanFoster]

just sitting there looking around at 0.

 

[StanFoster]

This is the Paxton airport where I keep my gyro. Lots of ultralights..and a very active skydiving club.

 

[CLS447]

Looks like a real nice place ,Stan

 

[barnstorm2]

Great Picts!

I like the look of that airport.

 

[LARRYEBOYER]

Stan, that sure looks like a long way down. Can you land on a postage stamp?

 

[StanFoster]

out flying this evening....farmers everywhere