Machine shop fired!.....and poll

[KenSandyEggo]

I went in today to see the progress (ha!) on my bracket for the hydraulic slave and it was still sitting on a shelf. I took my components and told them to forget it. One week has turned into 7, I believe.

Went to Hammerhead, who made my stabs, where I should have gone and asked in the first place, and asked for a good machine shop. Dropped off the stuff today and 1-2 weeks until there's something to look at.

I've been adding up this stuff and need to poll RAFers and AAI conversion people. If what I'm working on can provide a consistent 200-250 rrpm, without a taxiing runup, from a standstill with no wind, how much would that be worth? Retail for the handle is a little over $100, the slave is around $65, the braided hydraulic line is about $6 per foot and the 2 fittings are about $8 each. Now for the bracket. :eek: The first guy low-balled me and that is probably why they never got anything done. I'll have over $500 in the prototype for the first one for the reverse-engineering/design/production costs. He said that after production, each bracket may be around 50 bucks (aluminum....maybe steel), a little less if I order in some quantity. The bracket will mount with the foreward, existing bolt-hole where the spring is now attached, so basically there's no drilling or any kind of fabricating to do for installation. Should be a simple 1/2 hour hookup.

If I put an entire kit together with the activation handle (master cylinder), 8-10 feet of braided hydraulic line with fittings (I have to measure precisely), hydraulic slave mechanism to push the clutch lever and bracket for same, longer bolt to mount the bracket, etc., it's going to have to be somewhere in the $350-$400 range. I also have to modify each slave by disassembling it and removing an unneeded internal spring.

What does everyone think? I will test it thoroughly after I get it hooked up to make sure we can get those big numbers consistently. Considering what we have in our machines, does that seem like a price one would pay for superb prerotation speeds? If no one buys one, I'll have myself a $1,000 prerotator system. Oh yes. I can also include a circular facing of quality brake/clutch material to epoxy onto the bare clutch plate. This helps immensely and I can provide it in both sizes, if anyone still has the old clutch system.

[scott heger]

Ken , we all know you took the part to a local Tiajuana muffler shop to get it made. The problem is all the Mexicans are in the U. S. already, no one left to work on it. Hope you get it done and flying soon. Think Im going to fly to French Valley tomorrow. Call me if your around.

Scott Heger, Laguna Niguel, Ca N86SH

[KenSandyEggo]

Scott, what time you going, and e-mail me your phone number. (kensandyeggo@san.rr.com) I'll get it in the a.m. as I'm going to bed now.

[Aussie_Paul]

Ken, with the hydraulic "pull" you may not need the circle of friction material on the clutch face. Wouls you please conduct some of your testing without it?

Aussie Paul.:)

[StanFoster]

Ken: I would be tickled to get 200 rpm. If you can do that,,,I will buy one.

Stan

[Chopper Reid]

Ken, I would be thrilled to be able to get 200 /250 revs :D . My only proviso is that all parts need to be trouble free ,do long hours between any overhauls and the parts be readily available.

[KenSandyEggo]

Paul, I don't have a blank one now. I'm sure someone could send me one to try out "bare" if I ask nicely later.

Chopper, cylinder overhaul kits are readily available for the master and slave cylinder. If all works as I hope, I'll stock them. The bracket is being designed and a prototype will be ready shortly, at which time I will test the bejeebers out of everything and show all my prerotate numbers with photos.

[KenSandyEggo]

I had been using a Harley lever for several years and couldn't get rid of the mushiness. I don't know why that handle won't work. I've been switching between the Harley handle, original RAF handle and a bicycle brake handle. (photo attached) Guess which one works best? Dassrite...the bicycle handle. After I hook it up, I move the lever about an 1/8th inch and it's grabbing solidly. One problem, my hand is killing me from trying to squeeze the short handle. It's about 1/2 the size of the other 2.

Second best is the RAF handle, which I played with today. Got her up to 183 RRPM, but by the time I switched hands and grabbed the camera, it was down to 179 (photo attached). I think that I'll try the bike handle again and add some length to the handle with a pipe or something so I can squeeze it better and see what she does.

I sat for 2 hours on the ramp playing with the prerotator. One big thing in acquiring higher speeds is control of the throttle. It's difficult, especially when my throttle-body switches over from the idle-jet to the main-jet. There's a little lag, and if you don't control it carefully, you'll shoot up several hundred engine rpm and she'll start to slip. I found that if she did, I'd let go of the handle, reduce the engine speed slightly, smartly snap the handle back and she'd start smoothly climbing again. Even after 2 hours, she still locked in well and I could easily prerotate to 150+ every time.

I'm doing this with the cable system, so I am very confident that with the hydraulic activation, there won't be any slippage. I believe the lower-unit lever needs just slightly more pressure than we're able to apply with our mitts.

[KenSandyEggo]

179 RRPM...down from 183. You'll notice that it's at about 1650-1700 engine RPM.

Also, it was about 98 degrees at the airport today, and most of my engine running was well below 2K rpm, mainly between 900 and 1800. My new AAI radiator, made by Griffen, never let the water temp get above 182.

[KenSandyEggo]

I did some more playing around today after re-installing the bicycle handle. I wasn't getting enough leverage, so I went to an engineer friend and he designed this handle for me on some engineering program on his computer. :D O.K., just kidding. I hose clamped a wrench to the handle and it worked fine.

[KenSandyEggo]

I then taxiied to the runup area for the cross-runway to try some spinups. Here I am turning 164 at 1500 engine rpm. There was no wind today.

[KenSandyEggo]

Here we are at 171, still at 1500. You can see the top of my "leverage handle."

[KenSandyEggo]

And here we are after adding a little gas, at 191 and 1900 engine rpm. I actually saw 192, but could only get a pic at 191. The rotor was turning very smoothly, with no shake at the rotor-head. Shakes don't start unless the clutch starts slipping, and then they're no worse than what I always experienced with my old glass blades. I am still using the stainless-steel bicycle cable.

After playing awhile, I decided to get a take-off on the X-runway, 17, seeing as I was right there. The wind was still calm, as you can see by my limp string. I started to prerotate and got up to 185 and called for take-off. He had me taxi into position, and as I was already at 2,000 engine rpm, all I had to do was let off the brake and I started moving toward the runway. As I'm taxiing into position, I see 196 on the rotor tach. Before I could stop, I was cleared for take-off.

Here's where I screwed up. I started adding throttle, but I let go of the handle. Aaaaargh! I immediately dropped to 175 on the rotor and then had to wait for it to stabilize and start climbing to 200 before adding full power. When I let go of the handle, I didn't have enough forward speed to maintain the rotor speed.

I had noticed in my previous spinups that when the clutch starts slipping, it will still hold the rrpm attained for awhile and then slowly start dropping 1 rrpm at a time. What I should have done was maintain my grip on the handle and start adding power very briskly to at least 4,000 and gone to full power as soon as I noticed the rrpm increasing. I shouldn't have let go of the handle until I had enough forward speed to maintain the rotor-spin. Tomorrow's another day.....with a few changes shown in my next 2 posts.

[KenSandyEggo]

I removed the clutch plate and took a look at those 3 pucks. I then looked at the facing on the plate. The pucks are smooth and shiny, while the clutch material still has some rough feel to it. The pucks are only making contact with about 50% of the facing surface on the plate, so I drilled them out. I cleaned the face thoroughly with brake cleaner and proceeded to cut out a piece of my facing material to replace the pucks. I then mixed up my batch of the world-famous JB Weld and lathered it copiously into the recesses where the pucks were. I then lathered the rest of it and the back of my material and stuck it on. I grabbed all the clamps I could find and that would fit and clamped it down. After I took the pics, I found flat metal material to place under the clamps to spread the force more evenly, as with the 2 top clamps.

So tomorrow, I will be doing the same as today, but with 100% more face-to-face clutch/brake material. I can't wait. I have never felt any undue heat from the clutches after spinning and slipping away, sometimes for 2 hours on hot days.

[KenSandyEggo]

Another angle. Oh yeah. One drawback to getting up to those higher prerotational speeds. The centrifugal force tosses the cable grease out the top, all over my windscreen to the front and prop and tail to the rear. Hopefully I spun out all the excess today.

P.S. Go to post #10 for the start of my today's postings.

[Gary_in_Orygun]

Thanks for doing this research. I would not spend $1000 in a new prerotator system. Weight would also be a factor.

With my Harley handle and standard clutch setup I'm getting around 150 RRPM on prerotate (only about 110 RRPM with standard RAF handle). I might be interested in the clutch pad mods and trying to tighten my grip cable a little more. I want to exhaust the lower cost improvements.

[KenSandyEggo]

Gary, with the hydraulic system I'll be trying, there can't be more than a 1/2 lb. weight increase. It's just a hydraulic activation instead of cable. If the hydraulic really works well, it'd be at least 1/2 of the figure you mentioned. The weakest link to me, so far, seems to be the cable. Changing to a stainless, pre-stretched cable really made a difference. My Harley handle just wouldn't work for me, even with the new cable. I can't figure that one out. The RAF one worked better, but not as well as the bicycle-brake handle, which is too short. Facing the metal clutch-face helped a lot too. Now that I have both faces refaced totally, I'll see what I get today and post the results this evening.

[Aussie_Paul]

Fellas, iIt is all to do with having the surface areas working a 100% and the leverage to apply the force required!!!!!!!!!! On the Raf it is that simple.

Aussie Paul.:)

[KenSandyEggo]

It sure is Paul, but difficult getting there sometimes. I have some pics of today's spin-ups that I'll post in a little while. Hint: I broke the barrier!

[KenSandyEggo]

I unclamped the old 3-puck face today and all seemed secure. I sanded down both faces to get rid of any high spots, cleaned them with brake cleaner and put it together. I was thinking that I might have to drill another cotter-pin hole in the shaft, because the new pad is thicker than the recessed pucks were. But not by much. I was still able to get a pin in the shaft to lock the rear clutch-plate in.

First pic is of the brake material after I cleaned it. Notice the gold flecks. I was told what metal they are by the brake/clutch guy, but I forgot. The face is not as rough-looking as appears. I think it was shadows or the lighter colored flecks make it look that way.

[KenSandyEggo]

Second pic is of it put back together.

[KenSandyEggo]

This third pic is of the results. The engine was just shy of 2,000 rpm. After about a 1/2 hour of spinning up, I smoked the pads a little and wasn't able to get back up there. But then, we only prerotate just before we take off and don't sit there for a 1/2 hour in high heat spinning them up and heating up the clutch. When I got back to the hangar, I cleaned them again, sanded them a little and cleaned them once again. Ready to go again. The pads looked like they were making good contact all around. Not bad for an all mechanical prerotator, huh? When I started this, I was getting around 110-120 most often. So that's a gain of at least 85 rrpm. :D

[KenSandyEggo]

I almost forgot. Here's a pic of the windsock. The breeze was fairly mild, maybe 5 knots tops and it was close to 90 degrees out.

[Aussie_Paul]

Well done Ken.

Aussie Paul. :)

[KenSandyEggo]

Tanks Paul.

[GyroRon]

Just looking at you clutch pics, and reading what your going through to make more rpm, it would seem to me one way to make it easier to get better hookup in the clutch and less slippage is to make the discs larger in diameter. going from what looks like maybe 8 inches in diameter to say a foot and a half would make a big difference don't you think?

[Chuck Irby]

A foot and a half? 18 inches? You jest, right? :D

[KenSandyEggo]

They're 4.5 inches in diameter. It would take a lot of expensive, custom machining to make them larger even a bit. The outer plate is steel and coned and the inner one is aluminum with belt grooves and flanges. You want to donate?

[Aussie_Paul]

Ken, how about making the pad material 5" in diameter, and have it stick out 1/4". Might give a little more surface area.

Nah, just get that hydraulic system going!!!!

Aussie Paul.:)

[KenSandyEggo]

Hey, Paul. I got a blank clutch-plate now. Also scared the bejeebers out of myself as I careened down the runway. Went for that photo flight yesterday and in the runup area, I got up to over 180 rrpm. I made sure to maintain it as they cleared me for takeoff. As I round the bend to line up on the runway, I keep the pressure on the handle and start pouring in the gas. Now I've never been up that high (rrpm) at the start of my take off run. She gets up to 200 almost immediately and starts shooting down the runway. I should have lifted the nose, but I wasn't used to doing it that soon and forgot. She's going so fast, I'm having a hard time keeping the nose centered and I got into a sideways PIO. Luckily she was ready to fly, so I only swerved a couple times before she lifted off.

As to the clutch-face, that was just too much friction and heat while I held the handle while accelerating. I fried one puppy to a crisp. Looked like a scorched pancake and it broke loose from the clutch-plate. It was still on because of the center-hole. I think that facing both sides may be too much. I cleaned off the faces (the old 3-puck face still looked good) and readjusted the nut holding the clutch-plate on to snug it back up. So you will get your wish tomorrow Paul, as I spin her up with a full clutch-face on one side and the bare plate on the other. I'll probably do a few trials, like get a good set of pucks and maybe put them on the clutch-plate, just for grins. I'll see how it does tomorrow first. Might wind up that with a hydraulic actuator for pressure and just facing one side will do the trick.

[birdy]

Ken,
got your email thingy ,thanx for your help.[I just got to remember who I'v got git on to to order it now.]
BTW,for your help,if you email your postal adress I'll send you some vid footage of this gawdforsaken country if your interested.

[Harry_S.]

Ken:
The material was charred because your driver plate was *slipping*, not because of excess friction...been there, done that.

I don't think the engine rpm should get above about 1800 when your pr handle is squeezed...reason being, the driver will start slipping.

Anyway, this is what works for me.

Cheers.

[KenSandyEggo]

Uh, you lost me there, Harry. Isn't friction caused by slipping? That's what I meant, anyway. I got my best, 205 rrpm, at a hair less than 2,000 engine rpm. Now I have to find the right combo of facings on each side or one side. Has anyone ever replaced the 3 supplied pucks with Cleveland pucks? Based on past experiences, I doubt the originals are the best available, although they have held up well. The stuff I'm using now seems to have a rougher surface than the pucks. I don't know if that's bad or good. It's the best material the clutch/brake house uses, but after all that spinning, the burnt piece looked pretty thin. Maybe we do need to keep one face bare metal. I'll be anxious to get the hydraulic actuator hooked up and try out.

[Harry_S.]

AAAAHHHH!! I see your point of "friction and slipping." I think it's caused by having too much rpm.

[KenSandyEggo]

The bracket(s) are finally done. He gave me an extra one. I told him 1/4" offset toward the engine, but it's almost 1/2". I'll have to fit it on the gyro and see whether that is non-critical or if he has to make me a new one with the slave mounting holes moved over a little. Here are some pics of it mounted on an extra lower housing and some of the bracket itself. I came up with the idea of the little flange to hook underneath instead of using another mounting hole. The one it's in now already exists.

Once it's working, it'll be back to which facing configuration works best without burning or excessive slipping. I kind of am leaning that it'll be 3 new pucks to replace the old ones and a complete clutch material facing on the steel face. I believe the space between the 3 pucks will allow enough air in to prevent crisping up. That combo worked pretty well for me once before.

[KenSandyEggo]

Rear view..

[KenSandyEggo]

Next 2 are of the bracket alone.

[KenSandyEggo]

Last one of the bracket. Guy does nice work. Oh yeah.....patent pending.

[StanFoster]

Ken: I will let you have the prototype..serial # 001. But put my name on serial #002 :)

Stan

[KenSandyEggo]

O.K., Stan. There will be a $300 confirmed reservation fee though.

[KenSandyEggo]

Well, I drove way down south to buy Buna cups for the slave that would be compatible with the same fluid that the master is, and they were out of stock, so I have to wait to test the hydraulic activation for a little bit, about a week they said. In the meantime, I'll get the hose made and be ready to go when they come. The bracket and slave fit well on the gyro. I forgot to take my camera, so no pics to post.

[gyroman]

Well Kenny J

Any news on the prerotator advancements? Did you ever get the hydraulic lever installed?

[KenSandyEggo]

I still don't have the hydraulic actuator hooked up, but here's something interesting I noted today. A couple weeks ago, I decided to replace the 3 pucks that came with the RAF kit. They seem to last long, so the assumption is they're good. I don't know about that now. I popped for pucks at the local aircraft supply store and they were something like 50 bucks for 4 pucks! Yeeeeow!

I installed them a couple of days ago and saw that they weren't exactly flush with the clutch plate, so per Paul B.'s advice, I intended to grind them dowm to make them flush. I never got around to it and wanted to go for a flight today. I taxied out to the runup area, did my panel checks and then started prerotating. I could tell the pucks were grabbing good. As soon as it hit 75 rrpm, I pulled the handle in all the way and in a few moments, she was showing over 180. This is still with the bicycle cable. I called for take-off and kept the handle in. As I turned down the runway, it was still over 180, so I went to full throttle and let go of the handle. The rpm didn't drop at all and I was off smartly. She started slipping some as I added power, but didn't drop and just stayed at around 182.

I think that with the additional pressure from the hydraulic system, I should easily see over 200 rrpm on prerotation. I'll try to get that hooked up shortly, especially if I get the bracket made for my Ivo-prop brushes on Monday. It appears that expensive pucks are a good investment for additional rrpms.

[KenSandyEggo]

Spun up today to do a runway flight to test the new Ivo prop. I taxied back for another go-round and she wouldn't catch. I couldn't turn the Bendix with the prerotator plate, so took it apart. I thought the Bendix went bad, but part of the inner cable unwound and got stuck in the outer shaft. I guess it shouldn't have been a surprise with all the action it's gotten since I started monkeying around. Luckily I had an extra cable laying around and she seems fine again. Info on the Ivo prop is in the prop section.

[StanFoster]

Ken: I still want one when you get the bugs out of it..... :D

Stan

[KenSandyEggo]

I'll get on it as soon as I have the bracket made for the Ivo brushes. The hydraulic actuator is next on my list.

[Harry_S.]

Ken:

I'm on my third inner p/r cable and don't have another spare; shoppin' around now. I bought my other two cables from RAF. Do you have another source and at what price??

Anyone else have another source for this inner cable? While we're at it , how 'bout the outer sheath, too?

The inner cable won't last forever and I highly recommend that it be flipped end for end and greased every 25 hrs. as per the maintenance schedule. I thought I could get 150-200 hrs. without flippin', but it shredded.

[KenSandyEggo]

Harry, I neglected to flip it during all that static prerotating I was doing. I just forgot about doing it. I had been for the last 5 years. I got my latest inner and outer cable from Dick Wunderlich. He'll make either in any size you want. I don't recall the cost.