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Mangy Fox Dumb Stunts

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Posted

I've been a little quiet lately with my 70 hour per week business getting in the way of my Kitfox-ing. But, I do have a bit of a story to tell.

I had a bit of an incident while taxiing. I was turning around into a field next to a friend's grass strip and hit what I thought was just a patch of snow, that turned out to be more of a snow filled furrow. Long story short, I modified the tips of my Prince Prop.

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That day (Saturday 11-16) I gave a call to Hal Stockman (a national treasure in my book) to place an order for a new Luga/NR prop from him. I was surprised to find out he had one on the shelf and would ship it out to me asap. It turns out he shipped it that day!! What a swell guy! With a tear in my eye, I had to leave the Mangy tied down at the grass strip for a couple days (with a winter storm coming) until the new prop arrived.

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That Tuesday (!) my new Luga prop arrived from Hal. (Did I mention what a swell guy he is?). I quickly put the prop on, that Wednesday, and got the plane home. I found out that if I pitched the prop to where I thought it should be the trailing edge would contact my cowling. It was always close on my Prince prop, but it didn't hit. This did. So I flattened the pitch for clearance and got the plane home. I could over rev the engine at half throttle and all I could manage was 70 mph on the way home, but I got her home to her own hangar in time to avoid the coming blizzard. Here's the new prop on my kitchen table:

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My Prince was a 78" diameter by 48" pitch. It was a big prop. It was a takeoff and climb animal on my plane. Unfortunately the large diameter also meant it was pretty draggy and my top speed was a little better than 100 mph on a good day. This was never a big problem, because the STOL performance was so stellar. An acceptable trade off to me. The new Luga is only 72" in diameter. So I was preparing to take a substantial hit in STOL performance.

To install the prop with the way my cowl is configured, I needed to add a 1" spacer. Hal happened to have a used one for a good price and he asked me if I wanted to try a balance ring with it. I had seen these in Aircraft Spruce and was curious. I have similar balance rings on my big truck wheels and know they work awesome in that application, so I said sure, why not. Here is what the stack up looks like. (Spinner options are still being explored)

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AS of today, I have about 4 hours on the prop. I explored pitch settings starting at 15º which is the zero setting on the pitch gage. At that pitch, I would quickly over rev the engine on takeoff and level flight. So I bumped up the pitch to 17º. That only gave me 5200 on takeoff, but my cruise speed jumped up to over 120 mph in rough, unsettled air. I have it now at 16º with is appearing to be a nice compromise.

My takeoff distance may be a few feet more than with the prince, but not more than literally a few feet. Climb performance with the Prince was stellar to say the least. The Luga does well, but not as well. With the Prince I was seeing sustained climb rates of 1700-2000 FPM. With the limited time I have on this new prop, I'm seeing 1400-1600 FPM. Nothing to complain about by any means. However, I am seeing cruise speeds in the 110-115 mph range with 16º of pitch. I am not complaining. More that an acceptable trade off.

Now what everyone is waiting for: The Balance Ring. This thing is AMAZING!! This prop with the balance ring is so smooth, like nothing I have ever flown before. Every 912 I have ever flown has a little rough patch from 2500-4000 rpm give or take. Mine had it too. No amount of carb balancing or Dyna-Vibe-ing the old prop would get rid of it. With the balance ring this is GONE! Incredibly smooth! Our EAA Chapter has a Dyna-Vibe machine. I have used it many times and know they work well enough, but I was never totally satisfied with the results I saw on my plane or any other I helped with. This balance ring has, in my opinion, just obsoleted the need for a Dyna-Vibe or any other balancing machine.

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Posted (edited)

Nice report Larry but..... referencing the KF group many of us are not members and will not be able to see the pictures. :wacko:

Edited by wypaul
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Posted

Bummer about the Prince prop Larry, and nice to see that the Luga is working so well for you.  Something else for me to think about if I ever get my Kitfox 4 finished. JImChuk

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Posted

Did you try the luga without the balance master?

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Posted


Stinks to hear about the incident but glad  your flying so soon.  Hope you enjoy the NR prop I really like mine so far.

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Posted

Yeah I think I'm sold on getting the balance master for my 582, glad there wasn't anything more damaged for ya

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Posted

Did you try the luga without the balance master?

Yes I did.  The original flight home had no balancer.  It’s much, much smoother now. 

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Posted

Nice report Larry but..... referencing the KF group many of us are not members and will not be able to see the pictures. :wacko:

I didn’t realize this would link the photos to TeamKitfox!  Sorry.  When I get to my computer I’ll link the photos directly to AFF. 
 

 

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Posted

Did you try the luga without the balance master?

Yes I did.  The original flight home had no balancer.  It’s much, much smoother now. 

when I had my phazer motor with gsc prop on the stand a vibration would come in at a certain rpm, as rpm increased it would disappear, I might give one of these a try. 

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Posted

Maybe a balance master might be a good thing to try.

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Posted

d9qaw5J.jpg

 

s5biZVH.jpg

 

GHBIlAT.jpg

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Posted

What did Hal have to say about the straight blade R-118 or scimitar Luga SR-118 (79") on your engine?

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Posted

Looks good Larry, well the first couple of pictures anyway.

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Posted

What did Hal have to say about the straight blade R-118 or scimitar Luga SR-118 (79") on your engine?

I would probably gain some static thrust and improve takeoff marginally and possible a little more climb, but at the cost of considerable drag in cruise. 
 

I may still try a set of the 79” blades anyway at some point in the future. 

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Posted

Bummer on the prop:(

You'll have to let us know how you like the NR prop when you get some more time on it

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Posted

Sorry about your old prop Larry but thanks for the good information on the new set up. 

What RPM are you turning for max climb and max cruise speed?  I know Hal runs his above the Rotax posted limits of 5800 take off and climb and 5200 cruise.

it looks like the balancer goes between the hub plate and the prop so I assume it is punched to match the prop bolt pattern? 

That is a good looking prop, approximately what is the cost?

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Posted (edited)

Right now I’m getting 5500 on takeoff and climb out.  I run my engine up to 5800, no more.  Hal says it’s fine to 6200.  I’ll stick with 5800 max.  I cruise normally 5000-5200.  If I really need more speed I’ll run 5800 continuous no worries.  Not much more speed, but a lot more gas. 
 

The balancer is slotted to fit several of the patterns on the prop drive flange and center bored for the centering diameter. 
 

I payed $750 plus shipping for the prop. 

Edited by Av8r3400
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Posted

That's not a bad price.

I do have a couple questions for you cause I'd like to replace my wood CGS prop,  these may need to go in another thread but...

1:How does it perform compared to the Prince?

2:how easy is it to adjust (such as from cruise to climb)

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Posted

What did Hal have to say about the straight blade R-118 or scimitar Luga SR-118 (79") on your engine?

I would probably gain some static thrust and improve takeoff marginally and possible a little more climb, but at the cost of considerable drag in cruise. 
 

I may still try a set of the 79” blades anyway at some point in the future.

Yeah wow it sounds like that 72" is working great!  I would have thought you might overpower it and have to pitch it out of its sweet spot.

And apples and oranges but FWIW my 79" SL118 doesn't seem to have a speed penalty. I'm getting 120 mph with it while dragging two 14 foot long air mattresses through the sky.

And your power to weight ratio is better than mine so it would be interesting to see how the longer prop works on yours but dang I don't imagine it would be much better than what you are getting right now.

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Posted

Who makes and where do I buy one of those balancing rings? I've done everything I can and still have a few different RPMs where I have annoying but not serious vibrations or harmonics in my usable RPM range. Sounds like that ring is just the thing. Does it have mercury or something else around the perimeter that moves around to self balance the overall assembly?

 

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Posted

Who makes and where do I buy one of those balancing rings? I've done everything I can and still have a few different RPMs where I have annoying but not serious vibrations or harmonics in my usable RPM range. Sounds like that ring is just the thing. Does it have mercury or something else around the perimeter that moves around to self balance the overall assembly?

 

https://www.aircraftspruce.com/catalog/appages/engblncmstr.php?gclid=CjwKCAiAis3vBRBdEiwAHXB29A_pE_JSJaBmtAaL_35leOR-vjQG31ZlldL8QlOUJ9TXXiGP3yB5mxoClS8QAvD_BwE

 

 

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Posted

Who makes and where do I buy one of those balancing rings? I've done everything I can and still have a few different RPMs where I have annoying but not serious vibrations or harmonics in my usable RPM range. Sounds like that ring is just the thing. Does it have mercury or something else around the perimeter that moves around to self balance the overall assembly?

 

https://www.aircraftspruce.com/catalog/appages/engblncmstr.php?gclid=CjwKCAiAis3vBRBdEiwAHXB29A_pE_JSJaBmtAaL_35leOR-vjQG31ZlldL8QlOUJ9TXXiGP3yB5mxoClS8QAvD_BwE

 

 

I found the balancing ring here too...cheaper than others

https://www.aeroplans-blaus.com/en/balance-masters/334-balance-masters-helice-912.html

 

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Posted

That's not a bad price.

I do have a couple questions for you cause I'd like to replace my wood CGS prop,  these may need to go in another thread but...

1:How does it perform compared to the Prince?

2:how easy is it to adjust (such as from cruise to climb)

1.  Too early to tell.  I'm cautiously optimistic.  

2.  It is far easier to adjust than a Warp Drive.  It came with a pitch setting tool that I will do a video on in the near future.

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Posted

Who makes and where do I buy one of those balancing rings? I've done everything I can and still have a few different RPMs where I have annoying but not serious vibrations or harmonics in my usable RPM range. Sounds like that ring is just the thing. Does it have mercury or something else around the perimeter that moves around to self balance the overall assembly?

 

https://www.aircraftspruce.com/catalog/appages/engblncmstr.php?gclid=CjwKCAiAis3vBRBdEiwAHXB29A_pE_JSJaBmtAaL_35leOR-vjQG31ZlldL8QlOUJ9TXXiGP3yB5mxoClS8QAvD_BwE

 

 

I found the balancing ring here too...cheaper than others

https://www.aeroplans-blaus.com/en/balance-masters/334-balance-masters-helice-912.html

 

So what currency is that??

 

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Posted

Who makes and where do I buy one of those balancing rings? I've done everything I can and still have a few different RPMs where I have annoying but not serious vibrations or harmonics in my usable RPM range. Sounds like that ring is just the thing. Does it have mercury or something else around the perimeter that moves around to self balance the overall assembly?

 

https://www.aircraftspruce.com/catalog/appages/engblncmstr.php?gclid=CjwKCAiAis3vBRBdEiwAHXB29A_pE_JSJaBmtAaL_35leOR-vjQG31ZlldL8QlOUJ9TXXiGP3yB5mxoClS8QAvD_BwE

 

 

I found the balancing ring here too...cheaper than others

https://www.aeroplans-blaus.com/en/balance-masters/334-balance-masters-helice-912.html

 

So what currency is that??

 

euro....about 110 usd

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