2-stroker for UCD
05-21-2003 | 11:20 AM
#1
2-stroker for UCD
Hi folks, I need some recommendation on which 2-stroke engine that will give me unlimited vertical for the UCD ? Will the OS91FX be OK ? Heard about some problems with bubbling in the needle valve but maybe that has been sorted out. Is there any other 2C engine in the 90 class that will be better than the OS ? I will also appreciate info on the best prop to go with this engine. Thanks in advance..........
05-21-2003 | 12:24 PM
#2
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From: Greensboro, NC
2-stroker for UCD
The 91fx is a really good motor to run on the UCD. The only problem is propping it to get the transition and thrust you need from the throttle. The only other issue is all the weight you have to add to the right wingtip to balance out the reallllly heavy stock muffler. And if you use the stock muffler, youll have about 10 oz of goop on the wing after each flight. If I were to do another 91fx on my ucd, id rotate it about 30-45 degrees off center, so the exhaust points straight down the bottom. Maybe offset the head and the exhaust, so they balance each other out. And definately run a mousse can muffler on it. Less weight, better transition.
Alot of the guys have had great success with the ST90 and a mousse can. Ask dave mcdonald or m grambling. Theyve had st90s on for a while.
Alot of the guys have had great success with the ST90 and a mousse can. Ask dave mcdonald or m grambling. Theyve had st90s on for a while.
05-21-2003 | 01:55 PM
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From: Medford,
NJ
2-stroker for UCD
Can't speak to the ST but the Magnum .91 is plenty with the stock muffler. Pulls out of a hover strong, feels between 1.5-2 thrust to weight but I haven't measured.
05-21-2003 | 05:27 PM
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From: Medford,
NJ
2-stroker for UCD
APC 15x4W
It is the only prop I have tried so far, it worked so well I didn't try any others. Spool up is ok.
The engine pulls so well I had to add -50% expo to the throttle so hover is now at 1/2 stick. Without the expo I was hovering at 1/3 stick and had a hard time stopping it from climbing.
First tank was 9,700 and 15th tank was 10,900 with the 15x4W, stock muffler and 10% fuel.
No complaints so far except for the muffler wanting to loosen up.
I should mention that I mounted the engine upright. I have one inverted 2 stroke and it will be my last
It is the only prop I have tried so far, it worked so well I didn't try any others. Spool up is ok.
The engine pulls so well I had to add -50% expo to the throttle so hover is now at 1/2 stick. Without the expo I was hovering at 1/3 stick and had a hard time stopping it from climbing.
First tank was 9,700 and 15th tank was 10,900 with the 15x4W, stock muffler and 10% fuel.
No complaints so far except for the muffler wanting to loosen up.
I should mention that I mounted the engine upright. I have one inverted 2 stroke and it will be my last
05-21-2003 | 07:06 PM
#8
2-stroker for UCD
I have my 91FX mounted up right on my UCD. It runs great. I am using a 14x4W it peaks out at 11,800. I tried the 15x4W, but the throttle transition was slow, due to the heavy prop.
It hovers better with the 15x4W, but responce is just 2 slow.
It hovers better with the 15x4W, but responce is just 2 slow.
05-21-2003 | 10:22 PM
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From: Tyler, TX
2-stroker for UCD
I have a .91 FX with a Nelson Ultrathrust muffler on my UCD and I can confirm the recommendation. This is a great combination. Mine is mounted upright with no cowl. Great power.
Leonard
Leonard
05-21-2003 | 10:31 PM
#10
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From: Huston, TX
magnum 91 xls
I just put a Magnum 91 XLS (not XL) on mine, and for the price ($150) its great.
It seems to start much easyer inverted than the OS does. It idles smooth and even sounds like an OS. Has good transition out of a hover with the APC 15x4W
It seems to start much easyer inverted than the OS does. It idles smooth and even sounds like an OS. Has good transition out of a hover with the APC 15x4W
05-21-2003 | 11:19 PM
#11
2-stroker for UCD
APC 15x4W ?? It doesn't appear in APC's prop list http://www.apcprop.com/html/prop_list.htm and Tower's catalog. I suppose it's not updated ?
05-22-2003 | 01:31 AM
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From: Eagle,
WI
2-stroker for UCD
I have a Magnum XLS-91 2 stroke with a 15-4w APC. I am getting 10,500 rich for hovering and it is perfect. I am having a blast with this plane, and I paid $119 for the engine. Sweet.....
