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Engine basics => Engine set up tips => Topic started by: Ron Cribbs on April 16, 2015, 10:46:19 PM
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Hi,
I'd like to convert an FP .40 to CL and was wondering what size venturi to use and what needle, also best place to buy. I want to convert this for around $20 as I have less into the engine and hate spending more money on parts than the engine is worth.
I know I can lock the carb open, just want a cleaner look. Any help would be appreciated.
Ron
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Jim Lee will sell a delrin venturi for $8, at least when you see him person to person. Check with him. He's in the vendor section. I like .272 size for most set ups. OS needle valve available from Tower $13.56, or so. What plane at what weight will you fly? What muffler? All this effects optimum venturi size.
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Jim Lee will sell a delrin venturi for $8, at least when you see him person to person. Check with him. He's in the vendor section. I like .272 size for most set ups. OS needle valve available from Tower $13.56, or so. What plane at what weight will you fly? What muffler? All this effects optimum venturi size.
Dennis,
Thank you for the info, the plane will be a modified Twister. Not sure on the weight yet as it is still in the building stage. Most likely much lighter than a stock Twister.
I have a tongue muffler for it. Thank you for the tips.
Ron
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Ron, I'm pretty sure mine has a .257" in it, but I just deduced that by probing with the butts of drill bits. I've still got an OS wiggler for an NV. It runs good though. You probably already know the rest of the details of my setup. I followed Dennis' advice to get there, so what he says is good info.
Rusty
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I assume that you want a front NVA. All these comments are based on using the factory stock NVA which is a straight drop in.
Depending on the final weight, you may find the factory FP 20/25 venturi works. If it's a little bit heavy, the small venturi that used to be in the box when the FP 35 and FP 40 were first launched will probably be better. The factory FP 20/25 venturi is 6.5mm ID. the small FP 35/40 venturi is 6.75mm so, you buy an FP 20/25 venturi and run a 17/64" drill through it.
These are the parts—
FP 20/25 Venturi LXCW99 9.49 22312000
NVA 20-25FP-S LXCR49 13.49 22311000
The numbers are: Tower Stock No, current price and OS Part No.
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For what it's worth, i had a twister on an os 40. I liked it just fine, but the twister I'm building now will have an os25la. The 40fp is quite a bit of power for that plane, so in your situation, i would try the venturi suggested,
FP 20/25 Venturi LXCW99 without drilling it first. I'm pretty sure you build light, Ron. So this might work well and make for a nice run
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I built a few Twisters, all powered by FP40s. Midwest Magician, Walter Umland wing kit. Lengthened moments, slightly enlarged flap area, elevator/stab, increased 30%. Powered that with a Tower 40. Light weight, 34ounces total with engine and tank. Flite Streaks, Galaxy.The Magician flew at the NATs when rain and wind grounded many. All these engines use free flowing tongue mufflers. The Tower 40 in the Magician used a .272 Lee Venturi, one or two extra 10 thousand head gaskets. Powerful stunt run. Available 25s do not pull these planes with similar authority.
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Thanks for the suggestions everyone. I have plenty of info to work off of. To be brutally honest this will be the first non-Fox engine I have put on a plane.
I have a couple sweet Fox .40's that were re-worked by Lew Woolard that would be perfect. This FP was given to me with the kit so I am going to give it a shot.
Dane, I hope I can build this one light, using mostly kit wood on this!
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All my Twisters used kit wood. They flew great. Have fun.
Sent from my iPhone using Tapatalk
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You guys got me so interested in a twister, so I'll throw one together also!
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Have fun Dane,
Mine is highly modified. So much so it doesn't resemble a Twister whatsoever. I am told they fly well built as kitted, I just wanted to do something different.
Maybe you could turn yours into a Ringmaster...;)
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Maybe you could turn yours into a Ringmaster...;)
Lol! That would be neat! This one i want to be all box stock. I'm leaning on even using the cloth hinges. The twister was my first plane that i learned to fly figure 8's on. It was built by someone we didn't know, and was not a good build. It turned terrible because of a bad bellcrank set up. So, knowing what i know now, i think i can build a really nice one. And after this one maybe a Fancherized!
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Lol! That would be neat! This one i want to be all box stock. I'm leaning on even using the cloth hinges. The twister was my first plane that i learned to fly figure 8's on. It was built by someone we didn't know, and was not a good build. It turned terrible because of a bad bellcrank set up. So, knowing what i know now, i think i can build a really nice one. And after this one maybe a Fancherized!
R.O.T.F.L.M.B.O.!! Bro Dane!!Here's mine!! It too was a "Twister" that got twisted and has now been "Highly Modified"!! Well .... sorta'!! LL~ LL~
Jim
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Bro Jim,
That's pretty cute. I'll pm you my address..... ;D