Giving my FT22 more "umph"

[gloobnib]

I maidened my FT22 today that I built from a FT speedbuild kit, but I supplied my own electronics. The good news is that it flew fairly well out of the gate with only minimal trimming (4 clicks down elevator) required to achieve smooth level flight. It flew around at basically level flight cruising around the park for 5.5 minutes on a Turnigy Nano-Tech 1000 mah battery before hitting LVC.

The bad news is that it would barely climb and I had to fly it at WOT the entire time. It would do some very mild aerobatics (IE a single barrel role) but it lost so much altitude that I could never do more than 1 at a time. It would not loop (pitched straight up to about a 80 degree angle and climbed until it stalled). At the end of the flight the motor was very hot (certainly too hot to hold).

I think the CG is just about perfect but I could be wrong (this is my first successful scratch build). If I balance on the indicated CG marks, I get about a 5 degree nose-down attitude. I am guessing I have an issue with my choice of power pack. Right now it has:

• ESC - Turnigy Plush 30A w/ BEC
• Motor - HexTronic 24g 1300KV (HXM2730-1300)
• Prop - 8x4.5
• Battery - Turnigy Nano-Tech 1000mah 3S

The motor honestly looks a little tiny IMO, so my first thought was to replace it with something that has more beef. Or I could potentially swap out the prop? Both? Something else entirely? I have the following on hand for a quick swap out:

• Turnigy D2836/8 1100 KV outrunner
• 8x6 props
• 10x4.5 prop (probably too big for the slot)

Any suggestions are greatly appreciated! I'm hoping to get back out tonight around dusk for another go-round...

 

[rockyboy]

I don't think the 1100kV you have on hand will be too much difference - it will have more torque but lower RPM speed, which with the smaller prop that fits in the slow will be lower overall thrust.

I'd check two simple things as first trouble shooting steps;

a) is the propeller installed with the writing / numbers facing the direction the plane is travelling?

b) is the esc calibrated properly? turn on your transmitter, put the throttle all the way to 100%, then with the PROP OFF plug in the airplane battery. after the beeps pause, move the throttle all the way down. when those beeps stop, you should have throttle control again.

If that's all good and then I'd consider moving to a higher kV motor (1600kV or 1900kV) or a 9x4.7 SF prop (which might stress your current motor a bit - try not to fly with wide open throttle the whole flight) - you've got plenty of legs in the ESC to handle it though.

You also might find a few other FT22 builds here in the forums with recommended power setups too.

 

[gloobnib]

Thanks for the quick and thoughtful reply!

I'd check two simple things as first trouble shooting steps;
a) is the propeller installed with the writing / numbers facing the direction the plane is travelling?
b) is the esc calibrated properly?

If that's all good and then I'd consider moving to a higher kV motor (1600kV or 1900kV) or a 9x4.7 SF prop (which might stress your current motor a bit - try not to fly with wide open throttle the whole flight) - you've got plenty of legs in the ESC to handle it though.

You also might find a few other FT22 builds here in the forums with recommended power setups too.

Yes the prop is installed with the numbers forward. I had previously calibrated the ESC, but went ahead and did it again. I don't have a thrust meter in my basement (yet!) but it doesn't sound any different and doesn't feel different after re-calibrating.

The prop I'm currently using (8x4.5) is a SF prop. I read on another forum this afternoon saying that you basically shouldn't use SF props if the RPM exceeds 50K/diameter in inches. That would imply I shouldn't exceed 6250 RPM. At 12v on a 1300KV motor, I would theoretically be spinning at 15,600 RPM. Could prop flutter be robbing me of all my power?

I'm gonna go find me a prop wizard and see what my amp draw will be using the 8x6 prop and both motors. I'm pretty sure that it is going to be way too much for that little 1300...

Any other suggestions? I can always just TIAFO and report back tonight! (Try it and find out)

 

[IFlyRCstuff]

i might change the props to a non-SF but I doubt that would make a difference as large as what you are describing. also what is the C rating on your battery? something too low would not be good. Any other symptoms such as a hot ESC or a hot battery?
otherwise I agree a beefier motor with a larger prop would do it

 

[gloobnib]

i might change the props to a non-SF but I doubt that would make a difference as large as what you are describing. also what is the C rating on your battery? something too low would not be good. Any other symptoms such as a hot ESC or a hot battery?
otherwise I agree a beefier motor with a larger prop would do it

Thanks again for the quick reply. I didn't test the ESC temperature. The battery was no warmer post-flight than what I typically get after flying my Bixler on the 2200mAH version. I know it is not scientific, but I'd say they are just barely above body temperature post-flight. The nanotech batteries are rated at 45-90C.

I popped over to a webcalc (http://rcplanes.000webhostapp.com/calc_motor.htm) and it appears that I am definitely pulling too many amps through the little Hextronic motor. Per HK website it is rated for 7.5A and the web calc says I'm getting 18.2oz of thrust and pulling 10.1A!

I found a 9x6 APC prop in my giant pile of parts from 10+ years back. I popped that into the webcalc and put in values for my 1100KV motor and it came back with 19.4 oz of thrust and at 11.6A. The 1100kv motor is rated for 18A, so at least I'd be flying within spec.

I'm not sure if 1.2oz of thrust will make much difference TBH. 7% greater thrust doesn't sound like much, but ...

Of course this has the advantage of letting me fly again tonight, so I have that going for me. I'm gonna head back to the basement and do the swap. I'll report back!

 

[jpot1]

I found the torque on the bigger motor but lower kv to be too much for the FT22. I went with a 2200kv motor and a 6x4 prop and have plenty of power for rolls and loops.

 

[gloobnib]

Wow what a difference! I now have unlimited vertical. I almost feel like I have TOO much power; when I go vertical the plane specs out to where I lose orientation after about 3 seconds!

Right now I have the 9x6 prop and the 1100KV motor on and it feels like 200% more thrust. For comparison, about 40% throttle on the new setup feels equal to WOT on the old setup. Flight times are actually a little longer at about 7 minutes. 3 batteries went way too quick!

Thanks everyone for the input and sounding board. I guess the primary lesson learned is to read the specs more closely. An 8x4.5 is not "9x4.7 minimum" and a 20g 1300KV is not a "24g 1300kv minimum". D'oh!

ETA: The HK website calls the original motor "hexTronik 24gram Brushless Outrunner 1300kv" which exactly matches the minimum spec for the plane. But in the specs for the motor it says it weights 20grams. So maybe if I just had a prop that was 1 inch bigger? I can't imagine 1 inch would make THAT big of a difference!

 

[commandosqueak]

Check out this link. Its a handy calculator for working out things like thrusts etc. there is options for planes, drone and helis. Handy to have in your bookmarks!
Glad you got it sorted!

 

[kdobson83]

Your setup with motor and prop and battery is almost exactly what I had on my ft F22. And mine was so underpowered it barely flew. I moved on to other things but recently got a new motor for it. Same 8045 prop, same battery, but I used the emax 2822 or Flitetest's B pack, and it fly's awesome. No unlimited vertical but it'll cruise at half throttle and will do just about any manoeuver I try and picks up speed and climbs nicely. I love that hextronic 24gram motor but it's ment for smaller ships like the delta or flyer. I guess if u didn't paint, used a tiny 450mah battery, and saved weight where u could like smaller servos and what not the hextronic would work but it's just too small in my opinion. Spend $10 and get the B-pack motor from FliteTest. You'll have it in 2-3 days if ur here in the US and you won't be disappointed. No need to change anything else.

And after doing a little research when I went through what you are, I found some numbers that will help a tad. The hextronic 24gram motor on 3s with a 8045 will do about 400 grams of thrust, give or take. The emax 2822 motor on 3s with a 8045 prop pushes about 700-750 grams of thrust. So almost double. When your plane is around, what, 500-600 grams fully loaded, you can see why the hextronic has problems.

Anyway, good luck and have fun with that ft F22.

 

[SoylentGreen4579]

this is a tricky plane to hotrod.
the issue is wing loading. When you add weight to this plane, a set of bad stall habits form.
now, unless your happy launching, doing a circuit or two and landing is your thing, you will meet the wing loading demons trying to get enough battery in it to love it properly.
this one is at its best, essentially stock.

 

[gloobnib]

Thanks for the additional feedback.

Check out this link. Its a handy calculator for working out things like thrusts etc. there is options for planes, drone and helis. Handy to have in your bookmarks!

Bookmarked. I found that site, but it looked a bit sketchy to me so I moved on. No offense intended, but I was on a work computer and work in the InfoSec industry; didn't want to be 'that guy' in the company newsletter who was responsible for clicking an infected link on a website from China. Lol. I've since played with it on my home computer and agree its pretty nifty.

Your setup with motor and prop and battery is almost exactly what I had on my ft F22. And mine was so underpowered it barely flew. I moved on to other things but recently got a new motor for it. Same 8045 prop, same battery, but I used the emax 2822 or Flitetest's B pack, and it fly's awesome.

The hextronic 24gram motor on 3s with a 8045 will do about 400 grams of thrust, give or take. The emax 2822 motor on 3s with a 8045 prop pushes about 700-750 grams of thrust. So almost double. When your plane is around, what, 500-600 grams fully loaded, you can see why the hextronic has problems.

Good solid info. And it confirms what I had deduced, which is great. In all honesty I originally bought the hextronic to use in a twin engine setup in a FT Bronco (eventually) and now I've confirmed one thing - that the pair likely isn't strong enough for the Bronco since it calls for a Twin B pack. And it also confirms that I didn't get a bad motor and/or ruin the motor.

this is a tricky plane to hotrod. The issue is wing loading. When you add weight to this plane, a set of bad stall habits form. Now, unless your happy launching, doing a circuit or two and landing is your thing, you will meet the wing loading demons trying to get enough battery in it to love it properly. This one is at its best, essentially stock.

I'm right there with you. On the current setup I can hotrod it for about 3 1/2 - 4 minutes. But yes, I *really* want enough battery in this thing to get 7-10 minute flights at 75% throttle.

I 'upgraded' the battery to a 2200 3s shoved way way in the back of the fuse and it was unacceptably nose heavy. But against my better judgement ("just one more battery!") I flew it anyway. As long as I stayed on the throttle it flew fine, but once it stalls, it was nearly impossible to control. Luckily I found that out when it was up at about 50 feet so I was able to recover. I had to bring it in pretty hot to get it down safely. On the plus side, it handled the landing on grass at about 3x my normal landing speed with no problem. Needless to say, I won't be doing THAT again.

This plane is turning out to be a LOT of fun,I just really want more battery. It is now my favorite. I flew it today over lunch on the 3 1000mahs I have and it was 'over' in only 20 minutes. On my last battery something screwed up in my Taranis telemetry module and I didn't get the LV alarm on my radio. So I wound up flying it for 6 minutes on that battery until it hit the LVC on the ESC (without me noticing the 'soft LVC' symptoms). I was about 100 feet up and about 75 yards DOWNwind when it happened and the plane just spiraled/flopped/'leaf'ed to the ground. I was sure it was done for, but it doesn't have a scratch on it. Frankly, amazing IMO!

Anyway, thanks again for all the support/encouragement!

 

[j4ck4]

I maidened my FT22 today that I built from a FT speedbuild kit, but I supplied my own electronics. The good news is that it flew fairly well out of the gate with only minimal trimming (4 clicks down elevator) required to achieve smooth level flight. It flew around at basically level flight cruising around the park for 5.5 minutes on a Turnigy Nano-Tech 1000 mah battery before hitting LVC.

The bad news is that it would barely climb and I had to fly it at WOT the entire time. It would do some very mild aerobatics (IE a single barrel role) but it lost so much altitude that I could never do more than 1 at a time. It would not loop (pitched straight up to about a 80 degree angle and climbed until it stalled). At the end of the flight the motor was very hot (certainly too hot to hold).

I think the CG is just about perfect but I could be wrong (this is my first successful scratch build). If I balance on the indicated CG marks, I get about a 5 degree nose-down attitude. I am guessing I have an issue with my choice of power pack. Right now it has:

• ESC - Turnigy Plush 30A w/ BEC
• Motor - HexTronic 24g 1300KV (HXM2730-1300)
• Prop - 8x4.5
• Battery - Turnigy Nano-Tech 1000mah 3S

The motor honestly looks a little tiny IMO, so my first thought was to replace it with something that has more beef. Or I could potentially swap out the prop? Both? Something else entirely? I have the following on hand for a quick swap out:

• Turnigy D2836/8 1100 KV outrunner
• 8x6 props
• 10x4.5 prop (probably too big for the slot)

Any suggestions are greatly appreciated! I'm hoping to get back out tonight around dusk for another go-round...

Get yourself a Grayson Hobbies Super Mega Jet V3 setup and strap on it, I have a motor only due for delivery Saturday $47.00 with two prop choices. I went with the motor only because I have a couple 45amp ESC's on hand.