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tc1917(at)bellsouth.net
Guest

Posted: Mon Feb 01, 2010 5:13 am Post subject: 912

Been lurking and want to say a couple of things.  I had a 582 on my 

slingshot and it was a real performer, to me anyway.  It was LOUD.  It had a 

fuel consumption of around five and a half to six gals an hour + if I was 

loaded and heading to Florida.  I found some $$ and got hooked up with a 912 

UL from Kolb.  Got the works.  I gotta tell you all, with this set-up, I 

dont think you could beat it.  I think it is the most perfect combination 

you could have.  I use 3 gals per hour at about 85 mph cruise.  I can load 

it to the hilt and still get close to the same.  It has climb ability second 

to none.  I love my little slingshot.  Only one problem, rum rum.  Cant get 

rid of it.  So far I have done every modification known to man.  Still 

there.  One thing left is the gear box.  Not on the replacement part list 

but I have the belief it has tight gears in it or is elliptical or 

something.  You can pull the prop around with the plugs out and still feel 

it is tight in spots.  Now the problem.  How will I ever get the people to 

warrantee the fix after almost 300 hours on it.  The problem was original 

but time has gone on.  I am so embarrassed with this sound.  I cannot get it 

out even with the new helmet electronics.  At this point I am willing to pay 

for the gear inspection and replacement.  Should not have to.  Going to call 

Ronny today and see what I can do.  I dont want to pull the box myself. 

Would rather fly to him or to Lockwood and stay until it is fixed.  Anybody 

have any other ideas?  Not the mounts, exhaust pipes, carbs, (maybe timing), 

engine not really rolling, just sounds like it is, compression equal on all 

four, plugs replaced (twice).  Even ready to put the new muffler on the 

pipes except dont like the idea of hanging another five or eight pounds on 

the backside of my CG.  Someone want to come and fix this for me?  I will 

pay you.  Anyway, I still have the most perfect flying machine.  One thing 

for sure, you can always tell it is me coming.  Ted Cowan, Alabama, 

Slingshot 912UL

lucien

Joined: 03 Jun 2007
Posts: 721
Location: santa fe, NM

Posted: Mon Feb 01, 2010 6:35 am Post subject: Re: 912

 	  tc1917(at)bellsouth.net wrote: 	
		  Been lurking and want to say a couple of things.  I had a 582 on my 

slingshot and it was a real performer, to me anyway.  It was LOUD.  It had a 

fuel consumption of around five and a half to six gals an hour + if I was 

loaded and heading to Florida.  I found some $$ and got hooked up with a 912 

UL from Kolb.  Got the works.  I gotta tell you all, with this set-up, I 

dont think you could beat it.  I think it is the most perfect combination 

you could have.  I use 3 gals per hour at about 85 mph cruise.  I can load 

it to the hilt and still get close to the same.  It has climb ability second 

to none.  I love my little slingshot.  Only one problem, rum rum.  Cant get 

rid of it.  So far I have done every modification known to man.  Still 

there.  One thing left is the gear box.  Not on the replacement part list 

but I have the belief it has tight gears in it or is elliptical or 

something.  You can pull the prop around with the plugs out and still feel 

it is tight in spots.  Now the problem.  How will I ever get the people to 

warrantee the fix after almost 300 hours on it.  The problem was original 

but time has gone on.  I am so embarrassed with this sound.  I cannot get it 

out even with the new helmet electronics.  At this point I am willing to pay 

for the gear inspection and replacement.  Should not have to.  Going to call 

Ronny today and see what I can do.  I dont want to pull the box myself. 

Would rather fly to him or to Lockwood and stay until it is fixed.  Anybody 

have any other ideas?  Not the mounts, exhaust pipes, carbs, (maybe timing), 

engine not really rolling, just sounds like it is, compression equal on all 

four, plugs replaced (twice).  Even ready to put the new muffler on the 

pipes except dont like the idea of hanging another five or eight pounds on 

the backside of my CG.  Someone want to come and fix this for me?  I will 

pay you.  Anyway, I still have the most perfect flying machine.  One thing 

for sure, you can always tell it is me coming.  Ted Cowan, Alabama, 

Slingshot 912UL 	




Seems like we had a thread on this a while back which was actually my fault (was chasing a harmonic problem on my plane).



The tightness you feel when you pull the prop through with no plugs in it is the normal drag of the pistons in the engine itself. Also the oil pump adds drag once the oil pressure builds up. You'll feel all this is regular pulses in drag as you rotate it. 

If it really is tight in some regular spot in the prop rotation, you got a major problem, probably would have already put you down in a field somewhere. Sounds unlikely unless you delivered a heavy prop strike or something along those lines.



As for the rum-rum, it's not a problem unless it's bad enough to buzz things in the plane. If panels, windscreens, RAIM mounts for GPS's, etc., get blurry around their edges and you have a really hard buzz in the seat from it, yeah it's something you'll want to address ASAP. But if things are staying in focus and not moving and all you have is the noise, probably not a problem.



On my plane, the problem was only fixed by going to a different type of prop with a different resonance on the blades. Completely cured the vibration. There's an audible harmonic but things sit still in the plane with no blurs or wobbles. Problem solved.



IIRC, the 80 horse has a 2.27:1 ratio unless you order it with the 2.43. Every one of these I've heard with a 3 blade prop has an almost perfect 4th harmonic. That could be what you're hearing. 



Once you get into that engine things get bank-robbery expensive, so I wouldn't do that unless you really have a problem with the motor and have completely exhausted everything else....



LS

_________________
LS
Titan II SS

Thom Riddle

Joined: 10 Jan 2006
Posts: 1597
Location: Buffalo, NY, USA (9G0)

Posted: Mon Feb 01, 2010 11:16 am Post subject: Re: 912

Ted,



As a fellow Slingshot driver, I appreciate the fine qualities of our airplanes and wish I could add something to help with your non-Caribbean Rum Rum, but can't.  I was wondering if you have posted photos of your slingshot somewhere on the internet, or if not, could you post some on this list. I'd like to see yours and would guess none of the other Kolbers would object to seeing it either.

_________________
Thom Riddle
Buffalo, NY (9G0)

Don't worry about old age... it doesn't last very long.
- Anonymous

Thom Riddle

Joined: 10 Jan 2006
Posts: 1597
Location: Buffalo, NY, USA (9G0)

Posted: Mon Feb 01, 2010 11:17 am Post subject: Re: 912

Ted,



As a fellow Slingshot driver, I appreciate the fine qualities of our airplanes and wish I could add something to help with your non-Caribbean Rum Rum, but can't.  I was wondering if you have posted photos of your slingshot somewhere on the internet, or if not, could you post some on this list. I'd like to see yours and would guess none of the other Kolbers would object to seeing it either.

_________________
Thom Riddle
Buffalo, NY (9G0)

Don't worry about old age... it doesn't last very long.
- Anonymous

zeprep251(at)aol.com
Guest

Posted: Mon Feb 01, 2010 2:09 pm Post subject: 912

Ted,

Four of us went together on the purchase of a dynamic prop balancer.The first unit we experimented on was Mike Bakers 912uls Savannah.I thought it was a smooth running unit until we balanced the IVO.What a difference .



 G.Aman MK3C Jabiru 2200A Sensenich (balanced)

 



 



--

John Hauck

Joined: 09 Jan 2006
Posts: 4639
Location: Titus, Alabama (hauck's holler)

Posted: Mon Feb 01, 2010 2:32 pm Post subject: 912

Have you balanced a Warp Drive with HP hub  yet?

  

 Would be interested in your results, if you  do.

  

 Thanks,

  

 john hauck

 mkIII

 Titus, Alabama

  

  

 [quote]    Four of us went    together on the purchase of a dynamic prop balancer.The first unit we    experimented on was Mike Bakers 912uls Savannah.I thought it was a smooth    running unit until we balanced the IVO.What a difference    .



   G.Aman MK3C Jabiru    2200A Sensenich (balanced)



   

    

[b]

_________________
John Hauck
MKIII/912ULS
hauck's holler
Titus, Alabama

zeprep251(at)aol.com
Guest

Posted: Mon Feb 01, 2010 2:41 pm Post subject: 912

John,

 Left for Fla.soon after our purchase.I'll ask 

 

   G.Aman

 

  

   

 

   

 

  --

zeprep251(at)aol.com
Guest

Posted: Mon Feb 01, 2010 3:55 pm Post subject: 912

Ted,

 If you have not already done the dynamic balance thing,consider it.

 

   G.Aman

 

  

   

 

   

 

  --

slyck(at)frontiernet.net
Guest

Posted: Mon Feb 01, 2010 5:08 pm Post subject: 912

<Ted,



As a fellow Slingshot driver, I appreciate the fine qualities of our airplanes and wish I could add something to help with your non-Caribbean Rum Rum, but can't.  I was wondering if you have posted photos of your slingshot somewhere on the internet, or if not, could you post some on this list. I'd like to see yours and would guess none of the other Kolbers would object to seeing it either.



--------

Thom Riddle>

I've got the "caribbean" rum rum

Some kind of Bean anyway.

do not archive

[img]cid:34485858-935C-4DED-9706-7CF55C770598(at)frontiernet.net[/img]



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Dennis.Kirby(at)kirtland.
Guest

Posted: Tue Feb 02, 2010 2:53 pm Post subject: 912

Ted –  

   

Have you tried a two-bladed prop?  

That may eliminate the “fourth harmonic” which Lucien spoke about.  

   

As one who also suffered the innocuous, yet damaging, effects of harmonics from a specific engine/prop/airframe combination, I sympathize with your situation.  

   

(My solution was:  I ended up switching engines.)  

   

Just a thought …  

   

Dennis Kirby  

New Mexico  

Do not archive  

      [quote][b]

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