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Blowing up FT plan size & motors to match

#1
Good afternoon everyone! I'm still trying to educate myself on anything and everything RC planes. Hopefully I'm not asking something that has been asked to death.....

My goal is to take my busted up Timber X and use the electronics to build a FT Corsair. The electronics of the Timber X and the Power Pack C aren't similar though. Trying to figure out how to properly size (blowing up plans) of the Corsair so that the Timber X electronics are "scaled" to the plane size, if that makes sense. The Timber X parts are larger, so my line of thinking is that if Power Pack C = the Corsair at 100% of FT plan size, then Timber X electronics = the Corsair at X% of FT plan size (whatever that percentage equals out to be). I just have no idea how to make those calculations. I know that going too big brings it's own challenges such as wing spars, construction techniques, strength of the foam board, and such. Before I go that deep, I'd like to figure out how to do the scaling part of the equation.

Timber X
Motor = EFlite BL10 900Kv (130g weight, roughly 33mm case diameter, roughly 14.5mm case length, measured where windings are only)
ESC = 50A
Battery = 3S or 4S
Propeller = 13x4
Servos = 9g metal gear
Wingspan = 47"
Flying Weight = 57-60 oz (1613-1698g)

Power Pack C
Motor = 2218 1180Kv (76g weight)
ESC = 35A
Battery = 3S and 4S
Propeller = 10x4.5
Servos = 9g

FT Corsair
Wingspan = 46"
Flying Weight = ? (I'm assuming less than the Timber X)

How successful do you all think the Corsair will be with the Timber X electronics? Any need to blow the plans up at all or use the plans as they are and simply play with the mounting of components to make sure CG is on point? Is there anything that you think I'm not taking into account?

Just trying to educate myself on how to figure this stuff out so I can experiment more confidently.

Thank you for any and all constructive feedback!!
 

The Hangar

Well-known member
#2
The setup from the timber x on a 9x6 prop on 3s or 4s will actually fly the corsair at 100% really well! The issuie with upscaling the master series planes is that it doesn't account for the thickness of the foam staying the same. CG will stay just the same. The Timber X motor is heavier so your battery might be in a different spot than what Josh and John show in the build video. Also, every build is slightly different, and people use different amounts of glue, so there isn't a "right" place to put the battery that will work for every build. Just make sure the plane balances in the same spot that they have it balancing.
Have fun!
 
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#5
That's fantastic! I really didn't want to mess with blowing up the plans. I was thinking the motor was just too heavy and upscaling would be necessary.

I played with a flat foam board 3D plane and used all the electronics out of a Mini Apprentice S. All the electronics were way bigger than what the 3D plane called for, but I tried it anyway. I got the CG right on and it flies, but I have to keep it 1/2 throttle or more to keep it in the sky. The electronics are just too heavy. It does fly though......

I was worried about the same issue with the Corsair. I love how docile the Corsair is when Josh is flying it in the FT video. Looks like it can fly fairly slow, but then throttle up and go straight up with ease.

Are you all not worried that the Timber X motor is too heavy? I know it's got the power, but I'd really, really like to have a docile plane like the video for putzing around but then I like the idea of being able to really "punch it". I'm asking all this because I don't know. Really trying to learn what affects what and so forth. Thank you!!
 

The Hangar

Well-known member
#6
60 grams isn't that much to be adding to a plane this size. I have also heard that the MS (Master Series) planes like a bit of weight, and they fly better with a slightly higher wing loading. It should still slow down and have a lot of punch on your setup, especially if you use a 4s lipo.
 

BATTLEAXE

Well-known member
#12
Good afternoon everyone! I'm still trying to educate myself on anything and everything RC planes. Hopefully I'm not asking something that has been asked to death.....

My goal is to take my busted up Timber X and use the electronics to build a FT Corsair. The electronics of the Timber X and the Power Pack C aren't similar though. Trying to figure out how to properly size (blowing up plans) of the Corsair so that the Timber X electronics are "scaled" to the plane size, if that makes sense. The Timber X parts are larger, so my line of thinking is that if Power Pack C = the Corsair at 100% of FT plan size, then Timber X electronics = the Corsair at X% of FT plan size (whatever that percentage equals out to be). I just have no idea how to make those calculations. I know that going too big brings it's own challenges such as wing spars, construction techniques, strength of the foam board, and such. Before I go that deep, I'd like to figure out how to do the scaling part of the equation.

Timber X
Motor = EFlite BL10 900Kv (130g weight, roughly 33mm case diameter, roughly 14.5mm case length, measured where windings are only)
ESC = 50A
Battery = 3S or 4S
Propeller = 13x4
Servos = 9g metal gear
Wingspan = 47"
Flying Weight = 57-60 oz (1613-1698g)

Power Pack C
Motor = 2218 1180Kv (76g weight)
ESC = 35A
Battery = 3S and 4S
Propeller = 10x4.5
Servos = 9g

FT Corsair
Wingspan = 46"
Flying Weight = ? (I'm assuming less than the Timber X)

How successful do you all think the Corsair will be with the Timber X electronics? Any need to blow the plans up at all or use the plans as they are and simply play with the mounting of components to make sure CG is on point? Is there anything that you think I'm not taking into account?

Just trying to educate myself on how to figure this stuff out so I can experiment more confidently.

Thank you for any and all constructive feedback!!
I wouldn't scale up at all, do it original size. When it comes to the Corsair I would even put a larger motor in it, I have a 3536 1200 that would love that plane. If anything the C pack is enough to fly the plane but not much after that. It is nice to have the power when you need it then to not have it when things go south. Just because the power system is bigger doesn't mean you have to use all of it all the time. I can imagine the Corsair airframe could use a little bit more nose weight anyway. And I would totally use that 13 inch prop on 3s for sure, 4s I would prop down, but at 900kv backed by a 50 amp ESC, should spin it fine with room to spare. Plus the Corsair looks so much cooler with a larger prop
 
#14
*UPDATE*
I finished up my Corsair build last night. Ended up not increasing the size at all. I used the BL10 960kv motor and ESC from my Timeber X. 4S 2200mAH batteries. I got 5 successful flights on it today. What a blast!! First flight was with a 10x6 prop, second with a 10x7 prop, and the rest with the Timber X 13x4 prop. It was kind of twitchy with the smaller props. Flew super smooth and stable with the 13x4. Has all the vertical power I could want. I'm going to play with a 12x6 and an 11x7 just to see what would happen. I'd like a bit more speed than the 13x4 can do. Anyway, super excited to have built this plane and I love the power of this setup. Thank you to everyone for the input. Looking forward to having a blast with this thing!
 

The Hangar

Well-known member
#15
*UPDATE*
I finished up my Corsair build last night. Ended up not increasing the size at all. I used the BL10 960kv motor and ESC from my Timeber X. 4S 2200mAH batteries. I got 5 successful flights on it today. What a blast!! First flight was with a 10x6 prop, second with a 10x7 prop, and the rest with the Timber X 13x4 prop. It was kind of twitchy with the smaller props. Flew super smooth and stable with the 13x4. Has all the vertical power I could want. I'm going to play with a 12x6 and an 11x7 just to see what would happen. I'd like a bit more speed than the 13x4 can do. Anyway, super excited to have built this plane and I love the power of this setup. Thank you to everyone for the input. Looking forward to having a blast with this thing!
Awesome!! Glad it worked out well for you! A 12x6 might just be the sweet spot for speed and power - let us know what you find out!