3D engine selection help.
06-14-2002 | 06:27 PM
#1
3D engine selection help.
Need help selecting an engine for 3D flying.
I know little about all the engines out there so I need help choosing one. I have a plane that I was planning on using a GMS .47 or an O.S. .46 with a 12.25x3.75 prop on. "The GMS is supposed to produce more power." But I was hoping for an all up weight on my plane of 4.5 lbs. And right now sitting uncovered it weighs 4.5 lbs. So, I have roughly calculated/guestimated the weight of my covering will be 5-8 oz.
Now what I am wondering is how would the .46/.47 size engines I have listed pull this plane around with that prop for 3D flying? I plan on learning to hover and I want to be able to pull vertical from the hover without worry. Think either of these engines would be acceptable for the weight of 5 lbs.? I should also say that I live at roughly 5,000 feet elevation.
Now my next question is if those engines listed won't be enough to pull me straigt up from a hover with that much plane, what will? I've heard of engines being more powerful than the .47's and also weighing less. I don't really want a 4c unless it has more umph and weighs roughly the same as a .46 and also is in the same price range of the 2c.
Also I don't know if the plane specs will help but it has a wing area of 7.625 sq. ft. and I am looking at now having an AUW of 5lbs. Elevation is 5,000.
Thanks for any help,
Josh
I know little about all the engines out there so I need help choosing one. I have a plane that I was planning on using a GMS .47 or an O.S. .46 with a 12.25x3.75 prop on. "The GMS is supposed to produce more power." But I was hoping for an all up weight on my plane of 4.5 lbs. And right now sitting uncovered it weighs 4.5 lbs. So, I have roughly calculated/guestimated the weight of my covering will be 5-8 oz.
Now what I am wondering is how would the .46/.47 size engines I have listed pull this plane around with that prop for 3D flying? I plan on learning to hover and I want to be able to pull vertical from the hover without worry. Think either of these engines would be acceptable for the weight of 5 lbs.? I should also say that I live at roughly 5,000 feet elevation.
Now my next question is if those engines listed won't be enough to pull me straigt up from a hover with that much plane, what will? I've heard of engines being more powerful than the .47's and also weighing less. I don't really want a 4c unless it has more umph and weighs roughly the same as a .46 and also is in the same price range of the 2c.
Also I don't know if the plane specs will help but it has a wing area of 7.625 sq. ft. and I am looking at now having an AUW of 5lbs. Elevation is 5,000.
Thanks for any help,
Josh
06-14-2002 | 11:39 PM
#4
3D engine selection help.
Very cool. Lighter with more umph. 
That always makes mouths happy.
Now I have another question. What size prop would be ideal for 3Ding with the Irvine .53?
With my GMS .47 I have heard that it will tach at 13500 with a 12.25x3.75 prop. Which gives roughly 12 lbs. of static thrust according to Thrusthp.
So I would have to imagine the Irvine will put out oogles more juice. But I was crunching numbers for the Irvine and with the 11x7 prop it only gave 7 lbs of thrust. That makes me guess there's a different prop to use that gives more pulling power?
Or is there something I'm missing here? Such as the .47 won't be able to wind up with the nose sticking high and attached to a 5lb. plane? But the .53 has the power to do just that?
I need understanding.
Thanks,
Josh
That always makes mouths happy. Now I have another question. What size prop would be ideal for 3Ding with the Irvine .53?
With my GMS .47 I have heard that it will tach at 13500 with a 12.25x3.75 prop. Which gives roughly 12 lbs. of static thrust according to Thrusthp.
So I would have to imagine the Irvine will put out oogles more juice. But I was crunching numbers for the Irvine and with the 11x7 prop it only gave 7 lbs of thrust. That makes me guess there's a different prop to use that gives more pulling power?
Or is there something I'm missing here? Such as the .47 won't be able to wind up with the nose sticking high and attached to a 5lb. plane? But the .53 has the power to do just that?
I need understanding.
Thanks,
Josh
06-15-2002 | 02:23 AM
#5
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From: Pampa, TX
12.25 X 3.75 APC RPM
13.5K was about what I was getting with stock muffler, baffle removed. With Ultrathrust muffler (yeah, I know, $59) I get 14.7~14.9K. I don't know anything about the GMS 47, but 13.5K with this prop ain't bad....
Rest assured that the Irvine 53 with 12.25 X 3.75 will 3D a 5 lb plane with either muffler..with the UT my 5LB SE hovers at quite a bit less than half throttle..it's not even getting any gain from the UT muffler at this throttle setting.
As for understanding..I would compare both engines with the same prop..I'm not sure what the GMS 47 would turn with an 11 X 7, or what brand you tried.
A guy was flying a Pizzaz w/OS 46FX and 12.25 X 3.75 APC, then flew my SE, and was blown away by the power difference, same prop. He started looking for a Irvine 53 the next day.
I'm not trying to talk you out of the GMS 47, but I can say that the Irvine 53 is a very nice engine with the 12.25 X 3.75 APC.
Rest assured that the Irvine 53 with 12.25 X 3.75 will 3D a 5 lb plane with either muffler..with the UT my 5LB SE hovers at quite a bit less than half throttle..it's not even getting any gain from the UT muffler at this throttle setting.
As for understanding..I would compare both engines with the same prop..I'm not sure what the GMS 47 would turn with an 11 X 7, or what brand you tried.
A guy was flying a Pizzaz w/OS 46FX and 12.25 X 3.75 APC, then flew my SE, and was blown away by the power difference, same prop. He started looking for a Irvine 53 the next day.
I'm not trying to talk you out of the GMS 47, but I can say that the Irvine 53 is a very nice engine with the 12.25 X 3.75 APC.
06-15-2002 | 06:33 AM
#7
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From: Tucson
3D engine selection help.
My GMS 47 turns 12500 with an MA 11x7 (150 flights, your milage may vary). The muffler they use provides very little back pressure, so tank position is a bit more sensitive than for most others. GMS's are OK, and cheap, but one is enough for me.
I've flown a 5 pound plane that had a GMS 47 and 11x7 which was later upgraded to the Irvine 53. Big difference in power, unlimited vertical with the 53, better behaved too. Popular engine at my club, Never heard anyone complain about an Irvine. It will handle 12x8's
The OS 50 is nice too. Its a ringed engine which i have this idea makes it less sensitive to temperature. (?) i only have about 12 flights on mine. Sorry, don't have RPMs for you, but i can say it provides unlimited vertical for a fully loaded ultra stick with a MA 12x8. Also a well behaved engine, good throtle responce, no flame outs. the OS is 159$ i think it is about 50$ more than the Irvine, not sure if it is 50$ better than the irvine, but my experience with this engine has been so good 159$ seems cheap. Pretty sure i will get another one soon.
I've flown a 5 pound plane that had a GMS 47 and 11x7 which was later upgraded to the Irvine 53. Big difference in power, unlimited vertical with the 53, better behaved too. Popular engine at my club, Never heard anyone complain about an Irvine. It will handle 12x8's
The OS 50 is nice too. Its a ringed engine which i have this idea makes it less sensitive to temperature. (?) i only have about 12 flights on mine. Sorry, don't have RPMs for you, but i can say it provides unlimited vertical for a fully loaded ultra stick with a MA 12x8. Also a well behaved engine, good throtle responce, no flame outs. the OS is 159$ i think it is about 50$ more than the Irvine, not sure if it is 50$ better than the irvine, but my experience with this engine has been so good 159$ seems cheap. Pretty sure i will get another one soon.
