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General control line discussion => Open Forum => Topic started by: Ken Culbertson on November 16, 2024, 08:35:00 AM
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Does anyone know of a source for 9-9.5" three blade props available in both rotation directions? I can't seem to find any that are not for Multi Rotor. MAS produces a 9-7 pair but I am concerned that a 7 pitch might be a bit much. Has anybody tried to re-pitch a MAS prop? Some of the multi rotor props come in pairs. I suspect that the blade shapes are all wrong for stunt but I could be wrong.
What I want to do is shorten the landing gear on my new twin. It is in line and I think I have created a severe vertical CG issue. It also looks funny sitting as high as it is (which is probably the real reason LL~)
Ken
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Graupner made some like you want but good luck finding them.
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Multi rotor props are not strong enough for stunt ships. Don't go there.
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Multi rotor props are not strong enough for stunt ships. Don't go there.
Not to worry, I won't be going there. Hopefully the MAS can be re-pitched or I can trim for that pitch. Last resort, stick with the 2 blade BadAss 10-5. They come in pairs.
Ken
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https://www.xoarintl.com/multicopter-propellers/photography-drone-props/PJP-N-PH3-dji-phantom-3-beechwood-propellers/#spec
These look like they might work .....
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Does anyone know of a source for 9-9.5" three blade props available in both rotation directions? I can't seem to find any that are not for Multi Rotor. MAS produces a 9-7 pair but I am concerned that a 7 pitch might be a bit much. Has anybody tried to re-pitch a MAS prop?
Ken
Just buy the MAS 10" or 11" prop in the pitch you need and cut it down and balance as needed. I use a nail puller cutting pliers for the rough cut then sand and shape. I have shortened the MAS 11x6 all the down to 9-3/4" to use with a Brodak 40 or LA 46 and performed well and had great line tension. My experiment started with the MAS 10X5 3 blade, and it had poor line tension. I compared the 10x5 to the 11X6 and the 11x6 blades were a little wider. The 11x6 was a little too much load for the engines so I started cutting them down till I hit the sweet spot. It turned out to be a great prop in winds below 10 MPH. In winds greater than 10 MPH I experience wind up in the loops.
Al
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Just buy the MAS 10" or 11" prop in the pitch you need and cut it down and balance as needed. I use a nail puller cutting pliers for the rough cut then sand and shape. I have shortened the MAS 11x6 all the down to 9-3/4" to use with a Brodak 40 or LA 46 and performed well and had great line tension. My experiment started with the MAS 10X5 3 blade, and it had poor line tension. I compared the 11x5 to the 11X6 and the 11x6 blades were a little wider. The 11x6 was a little too much load for the engines so I started cutting them down till I hit the sweet spot. It turned out to be a great prop in winds below 10 MPH. In winds greater than 10 MPH I experience wind up in the loops.
Al
That sounds like the best solution. The 10 x 5 comes in both directions. Worth a try. I am using the 2320-810 BadAss and that prop was a recommended prop for a 3s battery. They did not test it over 3 which is strange. I know that static thrust is a useless measurement to us but it is curious that the 3 and 4s voltages produced higher thrust values than the 5 and 6s. It seems like the more I study this subject the less I know!
Ken
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I repitch MA props quite a bit. I heat the blades near the hub and give them a twist and hold till it cools for a bit, then check on a pitch gauge. They hold the setting even in summer sun shine. Remember, MA props are about an inch lessinpitch that marked because they use some other way to determine pitch. When using a Prather pitch gauge, I find them 1 inch less pitch. If measuring left hand props, you will need a different gauge. Jim Lee carries the gauge that Bob McDonald makes. I just got one and still getting used to measuring and reading lefty props.
Type at you later,
Dan McEntee
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You can make the Prather gauge into a lefty if you drill and tap the holes on the other side and do some copier machine magic for the scale. It's a pain switching back and forth though.
MM :)