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A couple mojo questions - 11/26/2007 10:24:02 PM   
Gringo Flyer



Posts: 2249
Joined: 1/16/2004
From: Formosa, ARGENTINA
Status: offline 		I have a 40 sized mojo with a OS 46fs. It has about 15 flights on it and it flies great. I am really learning a lot with it. It will harrier all day long and is as solid upright as inverted. Almost 0 wing rock. I am getting the hang of knife edges with it as well. This is my first plane that will do a clean KE loop and I am having a blast. The only problem I am having is with torque roll. I can pull it up verticle and hold it there pretty good but it just doesnt want to rotate. At times it can be a little squirrely vertical as well. It just doesnt seem to want to "lock in" like most 3D planes.

Any ideas what it could be? Where are you guys putting the CG? It just seems strange that it will do all the other 3D moves well except for the torque roll


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RE: A couple mojo questions - 11/26/2007 11:27:15 PM   
bbike


 

Posts: 292
Joined: 10/14/2006
From: East Orleans, MA, USA
Status: offline 		what size prop are you running? try a 12.25x3.75 apc

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RE: A couple mojo questions - 11/27/2007 12:50:25 AM   
Gringo Flyer



Posts: 2249
Joined: 1/16/2004
From: Formosa, ARGENTINA
Status: offline 		thats the one


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RE: A couple mojo questions - 11/27/2007 2:05:32 AM   
bbike


 

Posts: 292
Joined: 10/14/2006
From: East Orleans, MA, USA
Status: offline 		well, im not sure about locking into a hover, i only wish it was that easy, i am constantly using all of myimputs for my profiles, put the cog a little more aft. Try that and report back

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RE: A couple mojo questions - 11/27/2007 3:31:42 AM   
3dsky



Posts: 235
Joined: 1/1/2003
From: New Berlin, WI, USA
Status: offline 		I had the same problem with my first profile on a 2 stroke. I could lock into a hover all day but could not get it to rotate. I learned to torque roll using a Shock Flyer Extra 330 electric. It had the big diameter prop relative to the size of the plane and had a fast response feel to the motor. Just pulsing the motor would start the plane rotating. I found that the small prop on my OS 46 was not giving me the mass or torque needed to start the rotation. After getting the feel of the sweet spot with the Shock Flyer and getting used to pulsing the throttle (fast blips of power) I was able to do the same thing with the OS 46. I had to use higher nitro fuel and set the low end rather lean to get a fast response to the throttle. I now use a Perry V30 pump to even better success. So watch some videos of other guys using the same engine and get a feel where the sweet spot is to get the plane to torque roll. Some planes will sit a little on their backs and you may have to blip the ailerons with the throttle to start the rotation. The same sweet spot for a solid hover is not always the same for a torque roll. You have a great set up just keep trying, you will get it. I have switched to using a YS 63 4 stroke to get a little more punch. Good luck don’t give up.
Sounds like your are doing great on just 15 flights, I think it took over 60 for me to get it.

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RE: A couple mojo questions - 11/27/2007 9:45:42 AM   
AKFireMedic



Posts: 806
Joined: 2/2/2004
From: Anchorage, AK, USA
Status: offline 		The CG should be set so that once trimmed for level upright flight, when you roll it onto it's back it should stay at the same altitude or even climb a little. In other words, neutral, or slightly tail heavy.

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RE: A couple mojo questions - 11/27/2007 12:02:05 PM   
Gringo Flyer



Posts: 2249
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From: Formosa, ARGENTINA
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quote:

ORIGINAL: AKFireMedic

The CG should be set so that once trimmed for level upright flight, when you roll it onto it's back it should stay at the same altitude or even climb a little. In other words, neutral, or slightly tail heavy.


Then I guess I am not tail heavy enough. I will try to move it back some.

One thing I noticed with the mojo is that there is a big difference in flight characteristics between a full tank and closer to empty tank. On a lot of my other planes its noticeable to some extent but not as much as this plane.

I'll move the cg and try the other suggestions and report back. I hope to go out later this week.

Is there anybody with this plane that can tell me what they have the CG set at?


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RE: A couple mojo questions - 11/27/2007 7:21:41 PM   
PaulSwany



Posts: 4796
Joined: 12/7/2001
From: Bartlett, TN, USA
Status: offline 		Do you have any right thrust set? You'll want 2 - 3 degrees... You might also like the 11.5 x 4 APC prop for that engine. A good way to get them to start rotating is to put 'er on her back.... Just a enought to get it so start rotating.

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SwanysHouse
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RE: A couple mojo questions - 11/28/2007 2:00:38 AM   
AKFireMedic



Posts: 806
Joined: 2/2/2004
From: Anchorage, AK, USA
Status: offline 		CG should be somewhere "close" to 5 1/4" back from the leading edge at the canopy.

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RE: A couple mojo questions - 11/30/2007 7:41:56 PM   
MRMcFarlandM



Posts: 136
Joined: 12/17/2002
From: Kansas City, MO,
Status: offline 		Hi Guys,
I am Using a O. S. 46 FX on my MOJO and find that the throttle seems twitchy it either wants to rise slowly or descend.
I am always fooling with the throttle. It is making tail touchs and such a pain( my other planes have 4cycles in them and don't seem to act that way). Any Ideas on what the throttle curve should look like to make this easier.

Thanks

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Mike

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RE: A couple mojo questions - 11/30/2007 9:07:21 PM   
JustErik


 

Posts: 588
Joined: 7/19/2006
From: Charlottesville, VA, USA
Status: offline 		Mike, you didn't mention what prop you are using, but I would go for something around a 12x4 or 12.25x3.75. As far as a throttle curve, I've found the i like minimal movement on the low side of half-throttle and more as I go from half-throttle towards full throttle. Most engines seem to make 90% of their full power by the time the carb reaches 50% open. Try to adjust your linkage or TX settings such that your carb moves very little on the lower half. I hope that makes a little sense.

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RE: A couple mojo questions - 11/30/2007 10:20:50 PM   
Gringo Flyer



Posts: 2249
Joined: 1/16/2004
From: Formosa, ARGENTINA
Status: offline 		With mine I just play with the exponential on throttle every flight until it starts to feel right.

I have taken the mojo out a couple of more times and man is it a great plane. Its so fun to fly. I throw it in the car, go to the field, fuel up and fly. When I am done I throw it back in the car and go home.

This thing flatspins like its on steroids.

If I was going to build again I would build the shorter counter balances on the elevator. I built the full length ones and broke one side today dragging the tail.

I think I am going to try a little more right thrust like suggested and see if that helps the torque roll.


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RE: A couple mojo questions - 11/30/2007 10:47:31 PM   
PaulSwany



Posts: 4796
Joined: 12/7/2001
From: Bartlett, TN, USA
Status: offline
quote:

ORIGINAL: MRMcFarlandM

Hi Guys,
I am Using a O. S. 46 FX on my MOJO and find that the throttle seems twitchy it either wants to rise slowly or descend.
I am always fooling with the throttle. It is making tail touchs and such a pain( my other planes have 4cycles in them and don't seem to act that way). Any Ideas on what the throttle curve should look like to make this easier.

Thanks



You might also try a 11.5 x 4 prop on the OS 46...

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SwanysHouse
Home of the Taco, Burrito and Mojo BayBee!

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RE: A couple mojo questions - 12/1/2007 7:52:59 PM   
AKFireMedic



Posts: 806
Joined: 2/2/2004
From: Anchorage, AK, USA
Status: offline 		As well as the prop changes, take the ratchet off your throttle stick and see if that helps.

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RE: A couple mojo questions - 12/3/2007 10:12:39 PM   
MRMcFarlandM



Posts: 136
Joined: 12/17/2002
From: Kansas City, MO,
Status: offline 		HI Guys,
Thanks for the ideas. I am using a 12.25X3.75 prop I have also tried a 12X4. Think the Answer is to just fly it some and get used to the way a 2 cycle acts again.

Thanks

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Mike

(in reply to AKFireMedic)