RAF pre-rotator cable

[StanFoster]

I am posting two pictures here of my prerotator cable. I am thinking about having a shorter one made up to get rid of that extra kink. The cyclic is full forward right now. Does anyone out there agree that my cable needs to be 2-3 inches shorter?

Stan

[ToddP]

Stan,

It looks like it certainly could be a bit shorter. They're pretty expensive though, could you get this one shortened?

[teiland]

Stan, it does look a little long. I sent one back to Dick Wunderlich for shortening a few months back. His charge was very reasonable.

[Aussie_Paul]

...that pre rotator cable fits nicely after my stepped keel, engine lowering and shifting the axle back mods!!!!!! :D

Sorry Stan, I just could not resist. ;)
I know, I know. Try harder Paulie boy!! LOL :rolleyes:

You have to give me 10 out of 10 for never missing a stability opportunity!!! ;)


O.B. Aussie Paul. :)

[StanFoster]

Thanks all. I will check with Dick Wunderlich soon and see how much and how long he needs its.

Paul: If I was any happier with the way my RAF handled, I never would stop talking about it. :D

Stan

[Brian Jackson]

...If I was any happier with the way my RAF handled, I never would stop talking about it. :D
Well let's hope you get happier then! :) I never tire of reading your posts.

Best wishes,
Brian Jackson

[rgraffeo]

Stan,
I was told you could shorten the length by just removing the extension from the pulley bearing housing to the outer cable. This is where the bolt goes in to hold the outer cable in place. You could then use the clamp bolt to hold it in place.

I'm not sure if the inner cable would have to be changed.

[StanFoster]

Rudy: I will look into that tomorrow. I never considered taking the extension off. Maybe mine is different.

Stan

[KenSandyEggo]

Stan, Stan,Stan. You just don't listen to what I say.....er.....post. That was one of the big factors that got me closer to 200rrpm. I sent mine back to Dick and he shortened it for me. I can't remember the amount right now. Maybe he keeps track. You want it to go over the crossbar with the least amount of bend, but not too much so it won't pull out when the head is tilted. I don't see how one could shorten the outer cable-housing without shortening the inner one.

[Harry_S.]

Stan:

Your cable does look longer than mine. If I go to the airport tomorrow I will take several measurements and post 'em here.

Your pictures show several differences in that area from my machine...like a shorter standoff woter pipe for one. Do you know your kit serial number?


Cheers :)

[GyroRon]

Stan.....I am just going to have to start calling you Tommy Lee ;)

[Harry_S.]

Stan, I couldn't wait till tomorrow...besides, I needed to fill my gas cans, so I loaded up my cans and headed out.

I think if you removed the extension tube you would then have to shorten the rod that the inner cable slips into...unless the design was changed since my kit.

My dimensions are:
From shoulder to shoulder of the crimped ferrules is 52.5 ins. This would be the length of the outer sheath.

From the shoulder to the end of the ferrule is another 1.25 ins. So the inner cable S/B approx. 55 ins. I believe the inner cable is flush with the ends of the ferrules when laid flat.

My driver dimension, from the flush end of the pulley to the end of the extension is 8.5 ins.

Hope this helps you.

I can't tell on your pics but was your cyclic full forward? If it was, then I would say you have excessive cable length...if it was back, the pic would approximate the cables position in flight.

I like your lower rad cap. Mine is taller than the crossbar and necessitates the p/r cable routing under the crossbar. I may lower that water pipe. ;)


Cheers :)

[StanFoster]

Harry: Thanks for the trouble giving me those dimensions. I will check them out tomorrow. The rotor is tilted full forward in the picture.

I will look up the kit serial number. As you know...I bought this RAF partially built. The kit was purchased early 2002 and had all the upgrades except the 24th generarion rotor...which I initially upgraded to myself.

By the way...whats the idea of that extension anyway? Would my pre rotator cable plug in it it were removed? I am going to look at that tomorrow as I figured a cable 2-3 inches shorter would have a smoother bend. I held up a garden hose and mimicked my length I have now...then took off two inches and the curve looked much better.

Stan

[Harry_S.]

Stan: The purpose of the extension was for the EJ22 engine...larger engine dimensions?! The original drive rod was for the EA81 and they welded an extension onto the EA81 rod to accomodate the EJ22. A square tube is welded to the rod to accept the squared end of the inner cable...so that rod cannot be removed!!

Raising the plastic p/r cable guide on the mast, like I did, will really relieve the lower bend radius on the p/r cable. That move gave me about 30-40 more rrpm.

Did you get the video construction tapes when you bought your RAF?? If not, I could send you mine for your perusal.


Cheers :)

[KenSandyEggo]

"..........had all the upgrades except the 24th generation rotor..."

Have they got it right yet? That's more than one a year, isn't it? Can't wait for their 50th version.

[StanFoster]

Harry: I dont have the video...but I am going to consider shortening it. It works ok...but if I get 150-160 out of it...thats about it. I just use the runway most of the time and just prerotate to 110 or so and let the runway save on my pre-rotator. But...it sure would be nice to have the capability of 200.


Stan

[StanFoster]

Harry: I took your advice...raised the cable block on my mast..and moved it forward as well. As you can see in the picture...the bend is very smooth now. The cable is still 2-3 inches too long..but I am going to try it next week and see how this helps.

Thanks Harry.

Stan

[birdy]

You won't be able to shorten the outer with out a shorter inner Stan.They'd be made as a pair.
A better way would be to change over to a 914, the cable length is perfect for that application. :D :D
One of those works of art behind your machine in the pic would be all you'd need for a clean swap. ;)

[StanFoster]

David: I know the cable and outer sheath have to be shortened like amount.

That stairs in th ebackground would by a new SparrowHawk...not a 914. :D


Stan

[Harry_S.]

Stan: The curve looks real good now. Have you checked the p/r cable clearance from the scissors and the push rods?

I had someone sit in the seat and move the cyclic slowly from full fwd. to full aft and then around the clock. I had to reverse the bolts, on the scissors, to get good clearance. Just a check point Stan.

Did your cable length come out the same as mine?


Cheers :)

[Harry_S.]

Stan:

Ref. the RAF videos. If you would run across a set, it would be a good idea to latch onto them. They show in great detail...the complete assembling of the rotor head...pre-rotator Bendix...pre-rotator drive and pulley.

I have used the videos several times when doing maintenance/overhaul. I need more help as I get older...trying to remember what goes back where it belongs...before I took it out where it was. ;)


Cheers :)

[StanFoster]

Harry: I have the video on the rotorhead.

My cable just touches the control rods when the cylic is full aft. I was watching that when I determined where to reposition my cable guide block.

I am going to put something in the guide block that pushes the cable outward about another 1/2 inch...then I should not have any problems.

Stan

[Harry_S.]

Stan:

Rough up the mating surface on the drive plate and I'll guess you'll get 190-200 rrpm, with a 5 mph wind, in about a 50 ft. roll. :D


Cheers :)

[StanFoster]

Harry: I did rough up the plate...took the glaze off the pads...now my cable has less kink in it. I also took off some tie wraps that I had secured the outer sheath of the engaging cable. It feels like I have more squeeze power.

Heck...I may be able to do a jump takeoff now...and hover. :D

Stan

[Harry_S.]

Stan:

I can feel it...you're rarin' to go... :D :D


Cheers :)

[StanFoster]

Harry: Yep..I have been down long enough. I am hauling my gyro to Springfield to a ultralight..sport pilot seminar Saturday... Then its back to the airport and watch out. I cant wait to try out my pre-rotator.....I found a short in my bnc connector on my radio...so I didnt have to replace it.

I havent flown for almost a month now. I cant wait to get into the air again.

WARNING......here comes some more pictures of "blah" Illinois. I have so much I want to check out. I just love this sport.

Stan

[LARRYEBOYER]

Stan. Get some teflon spiral wrap and wrap it arround your flex shaft. Plenty of grease and pick up 50 rpm. :)

[StanFoster]

Larry: If I dont get satisfactory rpm's...I may try that.

Stan