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Best prop for 61fx on Chipmunk. need help
Hello,
I am wanting to know whats the best prop for the OS 61 FX for my Super Chipmunk. I have tried the MS 12x6 and it seems good but the plane climbs alot and has little vertical. I would like to get more speed and vertical. Any suggestions? [youtube][/youtube][link]http://www.youtube.com/watch?v=fw_lj8E99UY[/link] |
RE: Best prop for 61fx on Chipmunk. need help
Get a bigger engine.
Seriously a different prop will merely permit you to swap speed for thrust ( vertical ) or vice-versa. A different prop cannot make the engine produce more horsepower than it does now. Since you want BOTH best to step up to a bigger engine. |
RE: Best prop for 61fx on Chipmunk. need help
An effective prop for that combination that I think you will really appriciate is an APC 11x7.
John |
RE: Best prop for 61fx on Chipmunk. need help
I'll second both Opjose and JohnBuckner.
It sounds like your plane is underpowered for what you are looking for, so you probably need a bigger engine (OS .75 AX? It's a bolt-in replacement for the .61 FX). It appears the plane is flying in a more protypical scale like manner and will require some inertia to perform aerobatics (like a bit of a dive for extra speed for better vertical penetration in a stall turn). The optimum props for a .61 is 11 X 7 (better speed) or 12 X 6 (better climb) depending on your application. Who is the manufacturer of your plane, and what is the weight? Hogflyer |
RE: Best prop for 61fx on Chipmunk. need help
Hogflyer hit the nail on the head.
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RE: Best prop for 61fx on Chipmunk. need help
I agree. I was looking at going with a 4 stroke 90. I heard it has more torque and will turn a bigger prop.
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RE: Best prop for 61fx on Chipmunk. need help
Its a Goldburg. I am not sure of the weight. I was looking at a APC prop and see if that makes a difference. I currently have a 12x6.
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RE: Best prop for 61fx on Chipmunk. need help
Thanks Will that help it with the vertical climb?
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RE: Best prop for 61fx on Chipmunk. need help
While a .91 4C will have more torque, you won't get much more, if any speed. A .91 4C is generally regarded the equivalent to a .61 2C. You may want to consider something like a Saito 1.00 or 1.25. Both excellent engines and will pull your plane a bit better in the vertical maneuvers.
My suggestion is to fly it some more with the .61 FX and learn how to fly on the wing and use inertia. It's valuable experience many pilots don't get today. Hogflyer |
RE: Best prop for 61fx on Chipmunk. need help
Thanks I just started flying and had a solo trainer when I got into the hobby. So this one is a lot faster than what I am used to and I perfer not to crash it since it's hard to find these kits. Thank you for the advise and check out my videos on youtube.
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RE: Best prop for 61fx on Chipmunk. need help
I agree with Hogflyer. There is nothing wrong with having a scale like plane in your stable.
Not every plane has to be capable of balistic or wingless flight. You can keep one of each prop in your toolbox so if you want more speed one day, swap that prop in, or more thrust on another use the corresponding prop. Since you've already cut the cowl, upgrading may be more effort than it is worth. Instead when you choose your next plane, take the manufacturer's recommended size and increase that as a target size, then try to talk to others that have mounted larger engines just to be sure. |
RE: Best prop for 61fx on Chipmunk. need help
Wow talk about pointless displacement creep! The OP's airplane is the sixty size Goldberg SC, its not the 1.20 sized Great Planes SC.
Jsides First off you are just off your trainer and going to grossly oversized engines is only going to be trouble. Anything over a ninety fourstroke is a mistake for you. What you need to do is educate yourself to the importance selecting the right prop for each and every airplane/engine combination. That means having lots of sizes and trying them. No matter matter how much you spend on engines and how many cubes you stuff into that airplane if you use the wrong prop then it ain,t a gonna be a good flyer neither. First with that engine and airplane you are overproped. I don,t care how many charts or people tell you that 12x6 is the prop to use, it is not. Thirty years ago yes with the old crossported sixties it was a good prop. What you have is a good modern *****ie though and if you keep it muzzled down with that prop it will never work. That engine is a great engine but you need to let it breath. That means RPM. Don,t do anything untill you have purchased an 11x7 and flown it agine, whats it gonna cost four bucks. John |
RE: Best prop for 61fx on Chipmunk. need help
And an OS91 will pull a stump out of the ground but it will not give you more speed. With a 14X8 prop (I like Graupner) it will give you almost unlimited vertical.
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RE: Best prop for 61fx on Chipmunk. need help
ORIGINAL: JohnBuckner Wow talk about pointless displacement creep! The OP's airplane is the sixty size Goldberg SC, its not the 1.20 sized Great Planes SC. Jsides First off you are just off your trainer and going to grossly oversized engines is only going to be trouble. Anything over a ninety fourstroke is a mistake for you. What you need to do is educate yourself to the importance selecting the right prop for each and every airplane/engine combination. That means having lots of sizes and trying them. No matter matter how much you spend on engines and how many cubes you stuff into that airplane if you use the wrong prop then it ain,t a gonna be a good flyer neither. First with that engine and airplane you are overproped. I don,t care how many charts or people tell you that 12x6 is the prop to use, it is not. Thirty years ago yes with the old crossported sixties it was a good prop. What you have is a good modern *****ie though and if you keep it muzzled down with that prop it will never work. That engine is a great engine but you need to let it breath. That means RPM. Don,t do anything untill you have purchased an 11x7 and flown it agine, whats it gonna cost four bucks. John Oh well, I will just go brew up another cup and drink it black. Gene[:-] |
RE: Best prop for 61fx on Chipmunk. need help
The APC 13X6 Sport (looks similar to the "E" series props ) will pull a 9 lb. TF Corsair so it should work well w/ your Chipmunk IMO.
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RE: Best prop for 61fx on Chipmunk. need help
An OS 61FX will have about 9 lbs of static thrust with a 13x6, and a little more with a 13x4. I would throw a 13x6 on there and try it out, it is a good match for that engine.
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RE: Best prop for 61fx on Chipmunk. need help
I have thought about APC. IT seems to be stiffer prop and after talkin to a few I will have to try out the 13x6. From the 12x6 ms and a APC 12x6 I didn't notice much difference by looking at them.
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RE: Best prop for 61fx on Chipmunk. need help
Im not going to buy that engine. I have read through other forums that it's not really going to help with speed but vertical it will.
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RE: Best prop for 61fx on Chipmunk. need help
I agree with you. I am not going to upgrade the engine. It already whistles when it flies by but I will give that prop a try and see what happens. Any suggestions if APC might be a better one to go with over MS?
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RE: Best prop for 61fx on Chipmunk. need help
Just for fun fly the plane with a MAS then change over to an APC of the same size and see what happens. The APC props work a lot better but you will have to give it a try to see how much better. I only use the MAS on trainers or when I used to fly off of a weed field with a lot of gopher holes. The MAS takes a hit without breaking but if you hit an APC it's time to change props. You can also give the Xoar wood props a try just for the fun of it.
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RE: Best prop for 61fx on Chipmunk. need help
It's fast with the MAS prop. I will have to run it with the APC. Will it affect the tuning much?
I wish I had a GPS like I have seen people put on their planes to see the speed, ALT, etc.. See the video. http://www.youtube.com/watch?v=bEpdczfajoA |
RE: Best prop for 61fx on Chipmunk. need help
I fly with the SPA and have been experimenting with the OS61FX in a 7 1/4 lb Deception on 15% Cool Power fuel turning between 10,500 (Xoar) and 11,000 (APC). The thrust numbers are 9.4 (APC) and 9.6 (Xoar) pounds of static thrust. The vertical performance with the APC is basically unlimited. I would start with the APC since the Xoar is wooden.
Good luck Rich |
RE: Best prop for 61fx on Chipmunk. need help
I forgot, they're both 13x7
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RE: Best prop for 61fx on Chipmunk. need help
If you are looking for cheap power with lots of torque, check out an SK90. $99 bucks at Kangkeusa.com. It will throw a 15" prop and you'll go vertical all day. It's not a speed demon though. I have one on my Big Stik 60 and even here in the thin air of Colorado I can climb vertical till my heart is content. Also, this engine is easier to start than my OS46fx.
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RE: Best prop for 61fx on Chipmunk. need help
ORIGINAL: DenverJayhawk If you are looking for cheap power with lots of torque, check out an SK90. $99 bucks at Kangkeusa.com. It will throw a 15'' prop and you'll go vertical all day. It's not a speed demon though. I have one on my Big Stik 60 and even here in the thin air of Colorado I can climb vertical till my heart is content. Also, this engine is easier to start than my OS46fx. Anyone looking for an outstanding engine then take a look at the SK line. I like them bunches better then the OS line of engines but I don't fly hot rods. |
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