FMS 1400mm P-51 The Need for Speed

[AZFlyer]

I have the FMS 1400mm P-51B Snoot's Sniper, and it's a great looking plane. But, it's way too slow and is very difficult to handle on the ground. Anyone have any experience to share on how to get more speed out of this thing? I'm reluctant to drop the money on an upgraded motor without hearing whether anyone had any success with that (i.e, whether it made a significant difference).

Thoughts anyone? Thanks

[Kloverzero]

Same thing goes with the 1450 P-51D. It is rather slow. Ground handling is best if you do not deploy the flaps, otherwise it tends to nose over. I had the plane years ago and I put a Tacon Bigfoot 25 in it on 6S and the thing was a monster. The one that I currently have is stock, but I, like you am leery to purchase the upgrade motor as it is only a 40kv difference. I will probably just keep it like it is until I break it a little, and then go to a much larger motor.

[xviper]

For my 1450 P-51 FMS, I had 2 choices, both of which worked out very well.
1. Install the drive system from the Olympus 3D plane. It runs on 6s. You'll need a much bigger ESC, even bigger than what's in the Olympus due to the extra weight and drag of the P-51. The 2-blade prop from the Olympus is bigger diameter so you need to perfect your ground roll or it will nose over. The key is to use full UP elevator on high rates and blip the throttle to get it moving, especially if on grass. Once it's rolling, you can back off the elevator a bit but not too much. It WILL leap into the air suddenly so be ready to level out. Landing is the same. I use full flaps when landing but as soon as the plane loses enough airspeed, start forcing the tail onto the ground and keep it there. As it slows down, keep it moving with full UP as you taxi to where you want it to stop.
This set up is FAST, perhaps too fast for the airframe. It actually made me nervous about the structural integrity of the plane and I took that system out.

2. Install the drive system from the new FMS P-40. It has much higher kv on the motor and along with the bigger ESC, it will easily handle the stock 4-blade prop. This is what I'm flying my P-51 on now and I can stay on 4s. It is much faster than stock but not so fast as to be scary.

[AZFlyer]

Thanks xviper2. Option 2 sounds like the way to go. The reason I bought this plane, is because it looks pretty scale. So, I want to stay with the 4-blade prop. A Mustang with a 2 blade prop is hard to take seriously. I know it's faster, but really....yeesh.

I'm looking for the right motor/ESC combination to make this plane fly as good as it looks.

I put an eFlite Power 46 motor in it, and it was too long. The spinner stuck out about 1/2 inch. Also had to bore out the spinner plate. Not the best solution.

Agree with Kloverzero about the 40 kv difference. That doesn't seem worth the $50 investment.

Thanks guys!

[xviper]

The stock motor in the 1400mm is 580kv. The stock motor in my 1450 is 540kv. The P-40 motor is 650kv so a difference of 70kv for the 1400 and 110kv for the 1450. You may not feel nearly as much gain as I did.

[starcop]

The only thing I hear that others are doing is. Installing the 42-58 550Kv ( https://www.motionrc.com/products/fm...rushless-motor ) Slightly larger length can, with a 550Kv RPM. I was told this wakes up the P-51 using a 5S 4000mah pack. It's not a Customer Service recommendation, it's just something that other pilots are trying. I would also, change the propeller to a deeper pitch. I think like any airplane you change the voltage and, the propeller. That should give it more speed that is very noticeable. Again, this is at your own risk, anytime you change a product. The Manufacture won't Warranty a model that has been modified. I hope everyone's having a great winter this far. Keep an eye out for the new aircraft showing up on the website. Matt C/S Rep MRC.

[AZFlyer]

Thanks everyone. I read some good reviews on the Motion site about dropping in the FMS P-40 motor. Seems like that's working well.

Thanks!

[Grossman56]

Personally, I went with the 580 kv FMS motor with an 85A Mantis ESC. Also did the prop/zip tie mod on Big Beautiful Doll. Definite performance increase. When I put the 650 in my Freewing P-51, I took the stock Freewing motor(580kv) and ESC and just dumped them into Shangrila along with the prop/zip tie mod and again, a noticeable difference. For the money though, I think, in retrospect, I would go with the FMS 650kv in both. Remember you need to order the motor mount as well if you go that route.

Grossman56

[TomC]

Hello Grossman, If I purchased a Big Beautiful Doll could I go with a FMS 650KV and a 85A Mantis ESC with NO prop mod and get a noticeable speed increase? and would be any need for a 10AMP BEC ?

[wrongroad]

G'day gang,
I have done the motor mods in progression and these are my findings.
From the 540 installed in the V7 to the 580 mod is an increase of around 12%. I was a little underwhelmed by the performance gain as I had been quite happy with the 540. However, it was an improvement over the original motor.
After a while, the 650 became available so I took a gamble and installed one in BBD. I was still underwhelmed but realized that the model was going much quicker when I did a low pass and the big round loop at three quarter throttle impressed me.
The performance gain from the 580 to the 650 is, again, around 12%.
I still did not have the unlimited vertical performance that some claim to have. Yes, the Mustang goes uphill better then before but.......
The perceived lack of performance is an illusion that even tricked full sized Spitfire pilots as they transferred from bi planes to the swift mono wing machines. The top speed was much quicker but it took longer, in relative terms, to get to top speed. So, the pilots felt like they were actually going slower.
This was why I did not realize the increase in performance. Now, if I had of gone from a 540 to the 650, I would have had a 24% gain in one step. Then I think I would have noticed the difference! To seal that point, I let a pilot who had flown my BBD with the 540 motor, fly her with the 650. His response was simple. Wow, she goes now!!
All three of my Mustangs have the 650 installed now and I enjoy some performance gain and nice open loops and cuban eights. Low passes even get up a whistle at full throttle and five feet of the grass.
I have found that I have lost about thirty seconds of safe flying time but I can cope with that. It still means that I set up to land at the five minute bingo fuel warning. I just do not have as much in reserve for go a rounds.
The FMS 650 motors are cheap [about $45 Aus] and I have enough to do my Mustangs [done] and my two T-28's.
Now my figures are from basic math and readings from battery checks and eyeball observations and using a stopwatch over a set distance. [the length of our runway] So, they may not be 100% accurate but good enough to give a guide to set up if nothing else.
I have not changed ESC but that is my choice and I would recommend anyone who wished to change, to do so.
Nothing comes down overly warm, in fact, the one thing I can test is temp and there is only a couple of degrees in it and only when I fly at full throttle for most of a flight.
I believe it is well worth the outlay and I would not be at all surprised to see the V9 carry the 650 and the rear mounted servos as in the P-40 and new Trojan.
Regards and respect
Daryl

[Grossman56]

Hey Tom, I think Wrongroad says it best. I haven't used a BEC but that means nothing, if you want to use one, it's up to you, maybe some of the guys can offer a more experienced opinion on that.

Grossman56

[TomC]

Thanks...Great Info.;) I may start out cheap and try the Stock ESC on the FMS 650 motor...I do have a Watt meter to check everything before the first flight.

[wrongroad]

G'day Tom,
I will add to my comments and tell you that I only fly at full throttle for take off and the up part of a loop. If you are going to fly at full throttle for all your flight, put in the 'bigger' ESC.
I flew the Duchess Arlene today, for two flights, until the wind chased us home and I had to use a bit more throttle on the up wind passes but still did not see any rise in temps anywhere.
The wind was getting up over thirty kilometres per hour and the second flight was with a straight cross wind. The first was with the wind straight down down the strip. Perfect.
Regards and respect
Daryl

[TomC]

G'day Tom,
I will add to my comments and tell you that I only fly at full throttle for take off and the up part of a loop. If you are going to fly at full throttle for all your flight, put in the 'bigger' ESC.
I flew the Duchess Arlene today, for two flights, until the wind chased us home and I had to use a bit more throttle on the up wind passes but still did not see any rise in temps anywhere.
The wind was getting up over thirty kilometres per hour and the second flight was with a straight cross wind. The first was with the wind straight down down the strip. Perfect.
Regards and respect
Daryl

So, with a 650 motor mod to the 1450mm BBD I may can get away with using the stock ESC on the stock prop at ONLY a few full throttle passes?

[OV10]

So, with a 650 motor mod to the 1450mm BBD I may can get away with using the stock ESC on the stock prop at ONLY a few full throttle passes?

Hello TomC,
A 70A rated ESC with that motor was for turning a 3 blade and not a 4 blade set up. Yeah you maybe can get lucky in not taxing the system with a few full throttle speed passes but that is very subjective because for how long on those few and so on and so forth. If you want to jump into the higher realm of performance you probably should be more prudent now and not cheap out by using the stock ESC. So many non tech pilots out there do stuff like this without understanding the ramifications of the changes that they are inducing onto the power system. Anytime one adds a blade or increased diameter or changes pitch, the effects to what the motor demands for power becomes an exponential equation.
You really want to know if you've got enough margin, it begins with measurements using a tool such as a power/watt meter. Anyone and everyone that is messing with power mods to these electrical systems really should have a meter like this as a basic tool in their maintenance crib, you'll thank me later.

https://www.motionrc.com/collections/power-meters/products/gt-power-130a-watt-meter-and-power-analyzer

Best regards,

[TomC]

Thank Sir for your help..I do have a WATTS brand power meter I use often..I was just curious if the stock ESC would work..I am very much power hungry with my Warbirds and usually I purchase a bigger amperage ESC when converting them to 4s..looks like my best bet is to upgrade a P51 with 650kv motor and a Mantis 85 amp ESC...

Thanks,:)

[OV10]

That would of been my suggestion ;)
Or better yet the power plant from the 1500 Razor :cool:

[wrongroad]

G'day Tom,
Flying with the 70 amp ESC is my call and I have had no dramas. But I did also state that any one who wanted to change should do so. Perhaps I should have said do so as what OV10 correctly pointed out, as I can not be sure of how you fly, to upgrade the ESC as well.
I still cruise at 3/4 throttle but that is me.
Regards and respect
Daryl

[Dewey H Lee]

Hey OV l was just wondering. Is an 85amp sufficient for what it seems he is wanting to do. I don't know the formulas and have the knowledge that you do and was wondering more for myself since the esc is all I'm lacking to change to the 650. Your knowledge in the numbers is what I always look to in these matters. I'd appreciate your recommendation.

[OV10]

Dewey.........if your talking about one of the ZTW's absolutely.
Just a side note on calculations, the actual math formulas get pretty complex whereas you are not alone in not knowing and thus the reason for using the calculators such as Motocalc as well as getting actual measurements.
Good rule of thumb is that the ESC should have a 15% higher rating than what the max load that the power system demands. This is so the device will not be run at max levels which will ultimately stress it's capability and shorten the life expectancy. Without knowing the actual numbers of his system but knowing that others have come before with power numbers that push the 70A envelope and using the 15% buffer figure says a safe realm is 80.
Best regards,