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Prop selection Rotax 582 grayhead w B box 2.58:1

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Posted

So after lots of testing during my phase I flights I'm having problems with my 66" 3 blade GSC prop. when set to 11* the numbers are awesome but after just a short time the performance dies off. Ive checked and blade 1 goes to 12* blade 2 goes to 9* and blade 3 goes to 8* I marked all the blades and have reset them several times. in no time at all they are adjusting very consistently. this seems to be a normal problem for the GSC prop. sooo now what. I don't really want to fly it until the problem is fixed but the budget is pretty well fixed at the moment on broke. :unsure: I'm now saving and selling off my left over parts to get a new prop. what should I be looking for. I had a 2 blade ivo on the sky raider and it was awesome so I'm thinking of going that route again possibly with a 3 blade though. I currently have a B box with 2.58 gears. what would be the best prop for this setup and would hopefully still work good when I can upgrade the box later? 2 blade? 3 blade? how long? I've been doing some research and its mostly over my head. I do have an A box w 3.0:1 gears could they be put into the B box if it was better? I'm still just a newbie when it comes to all this ratio vs length vs number of blades etc. etc. 

 

Thanks Robert

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Posted

We had a 68" 3 blade on a 582 with the "B" box  and 2.58:1.  It worked VERY well on the MK IV we had it on.  That was just the ground adjust hub and when on just wheels or skis it worked great.

 

I would not go to the 3:1, I would stick to the 2.58 and a 3 blade 68" ultralight.

:BC:

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Posted

Hey High Country;

 

I have exact same problem with my plane, same prop, same degrees, and this the second engine I tried and they both show same performance, that gear box does not like GSC;

 

2 blade wooden prop work very well... I´m happy with the performance I get with 2 different wooden props I tried.

 

Regards

Dimi3

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Posted

the 582 wont pull the high pitch blades, you have to crank them about as flat as you can get them to get your take off RPM.  I learned this after my brother talked me into getting the high pitch, and I then burned up 3 IFA motors.. The TQ needed to flatten them out was just too much for the lil dewalt motor in the front of the prop.  All that being said, get the standard pitch and the blade blocks too so if the mood strikes you, you can try it out as a 2 blade... I keep the blade blocks in my plane as I have known some doltz who I cant say what his name is, but his initials start with Leonard Perry, who pranged a blade on the edge of the dock.... The blade blocks let me errr, um.. the doltz, remove said pranged blade and quickly convert to the 2 blade not so sexy version and got my, I mean his, dumb ass home.

 

:BC:

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Posted

AKflyer, Why don't you like the 3 to 1 Cbox?  We just put one on our plane and it seems to work great.  I'm sure you have good reasons, I am just trying to learn as much as possible.

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Posted (edited)

I currently have a B box with 2.58 gears. what would be the best prop for this setup and would hopefully still work good when I can upgrade the box later? 2 blade? 3 blade? how long? I've been doing some research and its mostly over my head. I do have an A box w 3.0:1 gears could they be put into the B box if it was better? I'm still just a newbie when it comes to all this ratio vs length vs number of blades etc. etc. 

 

Thanks Robert

Edited by Jim Chuk

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Posted

I have a C box on mine and I swapped back and forth a few times from 2.62:1 to 3:1  I get the best performance out of my plane with the 2.62:1.  The MK IV I flew with the B box had 2.58:1 and the 3 blade 68" ground adjust.  It was a sweet combo that ran very smooth.  IVO does not recommend nor condone the use of the 3 blade when running 3:1 but I know a lot of people who are doing it with no ill effects.

 

:BC:

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Posted

Thanks for the reply.

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Posted

I think if you run a 3 blade IVO with 3-1 ratio, you should have the knurled plates on the prop hub, and also make sure to run pieces of stainless tape across where the blades touch. If the tape gets cracks between the blades, that will show you have movement of the blades. That is not a good thing. Jim Chuk

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Posted

Thanks for all the input. I'm currently running a B box with 2.58:1 gears and i will stick with this for now. I was just stating that I also have an A box w 3.0:1 gears if it were better to use these gears in the B box. I just put a 68" 3 blade ultralight ground adjust on the visa. should be here in the next two weeks. sounds like I'm grounded again for a couple weeks. 

 

Thanks again for all your help

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Posted

I think you will like the Ivo, it takes two minutes to adjust and one and a half minutes of that is taking off and replacing the spinner if you use one.

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Posted

Thanks for all the input. I'm currently running a B box with 2.58:1 gears and i will stick with this for now. I was just stating that I also have an A box w 3.0:1 gears if it were better to use these gears in the B box. I just put a 68" 3 blade ultralight ground adjust on the visa. should be here in the next two weeks. sounds like I'm grounded again for a couple weeks. 

 

Thanks again for all your help

 

Unless someone had a machinist make those gears for the A box, it can't be a 3:1 ratio.  The only ratios Rotax had on the A and the B box are 2.0:1, 2.238:1 and 2.58:1.  The 3:1 gears did not come out till the C and E boxes and those gears are not interchangeable with the earlier boxes.

 

I am sure your going to like the IVO as its just a matter of loosening up the lock nut and using a screwdriver or some other round bar through the end of the shaft and tweaking in a little more or less pitch.  Shoot for around 6150 or 6200 on the ground and it should give you right around 6500 on take off and climb.  6500 is the max HP rpm and that RPM gives me the best climb.  If your EGTS go up too high in cruise, then tweak in just a tad more pitch.  For my flying (when I only had a ground adjust) I went for take off and climb, and enjoyed the extra few minuted it took me to get somewhere if I was going CC.

 

I can't remember, but I think the jam nut on the shaft is 1 1/8" or 1 1/4".  You may call IVO to make sure so you have a socket or end wrench to fit it when it shows up.  I think it was the only size I didn't have so I had to make a run to town to get a new wrench in the middle of the swap.

 

:BC:

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Posted

If my memory is correct, I was talking to Steve Beeaty (airscrew performance) years ago, and he said that some 3-1 gears were made, but they don't fit in any just any A or B box. I believe he said there had to be a bump out in the casting for the 3-1 gears to fit. The reason I questioned it in my earlier post, was I never heard of anyone having one. I did just look in my LEAF catalog, and can't see the bump out I'm remembering Steve mentioning. Also, they don't list 3-1 gears, just the 3 different ratios I mentioned. Jim Chuk

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Posted

Thanks for the input. I had a two blade ivo on my old skyraider and loved it that is partly why I chose to go this route again. Thanks for the heads up leni on the wrench but I already have a whole shop (used to be a self employed fabricator/mechanic) so should be good there. How much torque is required to lock the nut? Might be worth having a thick piece of aluminum cut at a machine shop to make a light weight wrench to carry along. I live high in the mountains and it would be nice to be set for climb when leaving on a CC but could be beneficial to adjust it to a more cruise setting along the way. thoughts??? as per the A box maybe I'm just remembering wrong.... darn now you have me curious I will have to dig it out this weekend and check just for my own curiosity. glad I'm not a cat.

 

-Robert- 

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Posted

I was just all over the IVO website, and didn't find the answer, but then I remembered that I should have the paperwork that came with my IVO prop somewhere.  Can't believe it but I found it right away!  Anyway, here is what it says, word for word:  The only time you need to lock the screw adjuster with lock nut is when you pitch the prop between neutral and two turns pitch decrease, in all other pitch setting screw adjuster stays where you leave it without a jam nut.  That was the second bullet point on page one, the fourth bullet point also deals with the lock nut, and it says:  Put safety wire through the hole in the screw adjuster to stop the  jam nut from falling off and into the prop in case it would loosen up.  Unless they have changed their opinion of it those same directions should come with your new prop.  I couldn't help my self though, and always tightened up the lock nut but didn't torque it down as much as you would expect for that large of a nut.  A flying buddy of mine stripped his lock nut fairly easy once by cranking on it like you would think it would need.   Jim Chuk

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Posted

Like I said, I carried the wrenches and extra blade blocks with me just in case.. I probly have 10-15 pounds worth of tools that I keep in the plane at all times.  If need be, I can tear the engine down or be able to take off any nut on the plane.  You really don't need that many wrenches / tools to be able to fit every nut and bolt on the plane as well as a roll of safety wire and safety wire pliers.   I think I have probly used the safety wire more than anything else in the tool bag.... makes the best hose clamps and has doubled as cotter pins, tail wheel chains, tail ski restraint etc over the years of flying the Avid.

 

:BC:

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Posted

Maybe a cheap option to resurrect your existing prop; I think I heard of somebody machining a thin layer off the inner surface of the gsc front hub plate to allow for tighter grip (if it is bottoming out before fully clamping the blades into position).  

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Posted

Maybe a cheap option to resurrect your existing prop; I think I heard of somebody machining a thin layer off the inner surface of the gsc front hub plate to allow for tighter grip (if it is bottoming out before fully clamping the blades into position).

I think that is asking for trouble. If the blades won't hold tight, they probably have been compressed to much already. Compressing them more may cause them to let go, and loosing a blade on a running engine is never good. Jim Chuk

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