Extreme Speed Prop Planes Discuss the need for speed with fast prop planes (Screamin Demon, Diamond Dust, Shrikes or any REAL sound breakin'''' plane)

Magnum, Irvine 46, what prop? I have no idea...

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Old 10-14-2007, 11:07 AM
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JoeyCoates
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Default Magnum, Irvine 46, what prop? I have no idea...

Hey guys, I have been flying for 20+ years but in all of that time have never had a seriously fast airplane. Sure I have been a bit interested, and I have had a few slick airframes that would maybe do 100-110, but nothing made for 125+. I really was not looing for one at this time either, but then I ran across the Magnums on Ebay ad for $75 and at that price why not.

I do have a few questions for you though as I am new to this.

#1. I have an Irvine 46 (red case jetstream carb) that I was thinking about using. I really do not know how these engines are timed ie sport, somewhere in between, or speed. Actually I know that it is not made for speed, but will it respond to a pipe or would I just be better off trying to find something else? I do not really want to dump a lot of money in it before I know how I like the speed models, but I do not want to put insufficient equipment in it either.

#2. I I can use this engine, where should I begine as far as a pipe is concerned? I am not very familiar with tuned pipes, but I am willing to learn. I do have a 55ax that I put a Tower Muffler on

http://www3.towerhobbies.com/cgi-bin...?&I=LXJB16&P=0

which picked up 900 rpm's, but I think that a tuned pipe would have a better result?

#3. Where should I start in regaurds to prop selection? I have no idea where to begin concerning pitch and diameter.

#4. What kind of servos do I need as far a s torque is concerned? I flya lot of 3D and helicopters where a pretty good bit of torque is required. I know that the increased speed needs power to move the surfaces, but then again they do not move all that much so you can set the linkages up with a pretty good mechanical advantage.

Sorry about all of the questions, I have done some searches but unless you put the exactly corect term in the search engine you end up with a lot of crap.

Thanks for the help!
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Old 10-14-2007, 01:42 PM
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Default RE: Magnum, Irvine 46, what prop? I have no idea...

46 ABC R/C MkIII

Features:

Disp (cu in) .46

Bore (in) .874

Stroke (in) .768

Power (bhp) 1.4

Practical RMP Range 2800-17000

Weight (no muffler) oz 13.8

Weight (w/muffler) oz 18.0

Mounting Bolt Size: 6-32

Propeller Sizes: 10x8, 10x9, 11x5, 11x6, 11x7, 12x5, 12x6
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Old 10-14-2007, 09:26 PM
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Default RE: Magnum, Irvine 46, what prop? I have no idea...

Joey:

Yes, thats a sport motor, but a good one that does perk up well with a decent pipe. Get a "Jett Stream" tuned muffler for her, but will only add another 2-400 rpm, still respectable rpm for a pure sport engine. Suggest you bite the bullet and get a scooter engine. The best sport engine is Jett of course, the 60LX king of the hill. Thing gives out 18K plus change, usually 19+, and yes is well worth the bucks as they just keep on running and getting stonger, honest. Have one into its 5th year, a 35, most of its running time spent club pylon racing. Took the gang 4 years to beat it, and only then about 50% of the time. It is a long term cost effective great sport engine. If you want good but cheeper, get a Webra 55, add a Jett Stream pipe and 10 X 10 apc. Will outrun the Jett 60's if the 60 pilot is not sharp on the needle. Think my 60 would burn up trying to lug a 10 X 10, frankly don't know how the smaller Webra does it, but it sure does, and does it well. There is no substitute for a good engine. Either given will please you for a long time (if you can handle it) You must always break in these engines correctly to get the designed performance. ENJOY
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Old 10-14-2007, 09:55 PM
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Default RE: Magnum, Irvine 46, what prop? I have no idea...

Joey:

Yes, thats a sport motor, but a good one that does perk up well with a decent pipe. Get a "Jett Stream" tuned muffler for her, but will only add another 2-400 rpm, still respectable rpm for a pure sport engine. Suggest you bite the bullet and get a scooter engine. The best sport engine is Jett of course, the 60LX king of the hill. Thing gives out 18K plus change, usually 19+, and yes is well worth the bucks as they just keep on running and getting stonger, honest. Have one into its 5th year, a 35, most of its running time spent club pylon racing. Took the gang 4 years to beat it, and only then about 50% of the time. It is a long term cost effective great sport engine. If you want good but cheeper, get a Webra 55, add a Jett Stream pipe and 10 X 10 apc. Will outrun the Jett 60's if the 60 pilot is not sharp on the needle. Think my 60 would burn up trying to lug a 10 X 10, frankly don't know how the smaller Webra does it, but it sure does, and does it well. There is no substitute for a good engine. Either given will please you for a long time (if you can handle it) You must always break in these engines correctly to get the designed performance. ENJOY
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Old 10-14-2007, 10:23 PM
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Default RE: Magnum, Irvine 46, what prop? I have no idea...

I think it is important to know what type of plane. I think you should use a Jettsteam or ultrathrust muffler and start with a 9-7, 9-8, 9-9 prop. Maybe look at some of the pylon props, 8.75-9 etc.
You really need to have an objective with a particular airframe. I good go fast design is a great planes Viper and your engine would work well with this as well. Should be good for 120 mph+ easy.
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Old 10-15-2007, 12:00 PM
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Default RE: Magnum, Irvine 46, what prop? I have no idea...

Well the airframe is the Weston Magnum that are being sold on Ebay, for $75 shipped I just had to try it.

Ok, I went and bought an engine and pipe to go on it. I picked up a Picco 45 with header/pipe for $40 at the LHS. It was up there on consignment and I figure the pipe alone is probably worth $40 so what the heck, it was not much of an investment. I am going to post some picks of it on the glow forum where someone can hopefully give me some pointers, but the engine is pretty clean, it has great compression, and the bearings are good. I have already disassembled it to check for rust and clean it, but someone must have pickled it when they put it up as the crank/bearings have no rust on them. Very clean inside. And no scoring on the piston/liner at all.

Oh well, for $40 it is worth a shot and they were performers back in the day..... Not too much info on them though.
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