I've been working on my LT-40 since spring. And now I'm finally covering. I hope to finish covering by the weekend and fly it Saturday.

Long story short, I now have:

AXI 2826/20
5S2P battery setup
JETI 40Amp ESC
11x6 E-prop

The gotcha.. the AUW of the plane is around 8lbs. Tower's website says this motor is for planes up to 6.6 lbs.

I'm a little concerned that the plane is too heavy for this motor.

Will it fly????

And how well??? Will it limp off the ground? or will be able to pull simple aerobatics?

TIA

Hi I have a 7.5 pound 81" Cub ARF with an AXi 2826-12 running on four cells at 3200 ma. My prop is a 13 X 8 APC. I am using a 40 amp Jeti. This combo has given me over 50 outstanding flights at 3,000 feet and 100 degree plus temperatures. Plane will easily take off in 15 to 20 feet, loop roll, spin, fly inverted and land with 2 to 5 bounces. One of the most fun flying planes I have had in long time. Norm

I have an LT-40 with this set-up:

14 cell, 3600 NiMH battery pack
Castle Creations Phoenix 60 Amp controller
E-Flite Power 32 motor
12x6 E-prop
All-up weight is 8lb 4oz.

It flies great but being as heavy as it is, it lands a little fast for a trainer, so I have to cut power completely before entering the base leg. It will loop, roll, and fly inverted. Don't have enough experience to say what else it will do, but I'm just learning. And the landing gear bent on just about every landing. I modified mine by running an 1/8 hard wire from around one screw of the landing gear strap to the opposite landing gear leg, just above the axle. The 1/8 wire is secured to the landing gear by wrapping fine copper wire around the wire and landing gear and soldering over top of it. It has held up really well but I do run the risk of damaging the plane on a really hard landing, the gear doesn't have much give any more.

Your set-up should work OK, assuming you have an AXI 2826/12. I couldn't find any data on a 2826/20. Your 5S pack will push both your controller and motor at full throttle, but you shouldn't need full throttle very much. You also don't say what your pack capacity is, it probably needs to be greater than 3000 mAh to work well.

Good luck and happy landings.

Sorry, I typoed..

The motor is a 2826/12.

My batteries are Thunder Power 4200mAh.

hi there from Toledo:

This setup works well in my LT40:

an Axi 412018 with radial mount kit,
a Dubro spinner nut M8 x 1,
standoffs as needed for mounting,
a CC phoenix 80 ESC,
an extension lead with toroid choke (red lead cut out),
a 5s lipo 4000mah or so,
an APC 15 x 8 eprop,
a 5 cell nimh pack for the rcvr and servos,
a safety jumper between the batteries and the ESC,
two servos in the wing with a "y" extension or separate channels for flaperons.

That set up flies mine quite well.

ciao -rjf

The AXI 2826/12 is a great motor - 4S2P A123 packs handle Telemaster Electro nicely. Have also modified other 40 size models using same set up or 3S4200 LiPos with excellent results. Sig Rascal, Bantam II, and Elimianator.

My Kadet flew today!!!!


I honestly didn't think it would fly. The motor, according to Tower, is rated for planes up to 6.6 pounds. My bird tips the scales at 8.

But I did have a problem. And I need help to solve it.

First the specifications.

AXI 2826/12 motor
JETI 40Amp ESC (no BEC)
5S2P Thunder Power 4200mAh Batteries. (1 3S20, 1 2S2P wired in series)
11x6 Master Airscrew Electric Prop
Finished weight about 8 lb.

The symptoms.

On take-off when revved up to full throttle, there was a screaching sound.

The plane almost jumped off the ground. There was a bit of a wind, but others at the airfield said it took off good.

After about 2 minutes, the motor cut out. Stopped. The flight was a few full throttle loops, etc.

We thought something was very wrong. We landed. (I didn't fly it, a very good, very experienced pilot flew it.)

After some talking and deliberating. I swapped batteries to another set. I was thinking maybe my batteries weren't fully charged. But I had charged them before leaving the house. Or at least I had them on the charger. I'm still figuring out all the technology.

The same guy flew it again, and again, at about 2 minutes, engine cut out.

Next we decided on a test. First we wired up the 3S battery by itself. We put the plane in a ground test stand. We ran the motor alternating from about 50-60% throttle. With occasional 15 second bursts to full throttle. Ten minutes went by, no troubles.

Next we decided to try flying it on 4S setup. I removed a 3S battery pack and installed a 2S, and hooked the two 2S packs together into a 4S pack. We did not change anything else. We decided to fly it, we wanted to see how it would fly/behave. The take-off run was noticeably longer, but it did eventually lift off. We flew the bird for 10 minutes, non-stop, at about 50-60% throttle. And landed with battery power to spare.


So... Now I need to figure out what happened. I'm thinking there wasn't enough pitch in the 11" prop, the motor at full power spun too fast, the ESC shut the motor off.

So... What do I do. I want to get the take-off run back to the shorter length. I want to eliminate the engine cut-out. I want to return to the 5S2P setup if possible.

Suggestions?

I have a watt meter. So I can do some testing...


Help?


TIA


Lyndon

Hi, I think that you have the wrong prop. I use 3200 ma 14.1 with my 2826-12 and fly a 81 in 7+ pound Cub with great success. My prop from day one has been a 13 X 8 Norm

I'm reluctant to go to a larger diameter prop. I don't have a lot of ground clearance.

A larger prop would mean I'd have to redo the landing gear.

Put larger tires on it, go to a 3 bladed prop, or turn it into a tail dragger. a 12 X 6 on that motor ain't going to hack it. Norm

I'll be stopping at the LHS tonight after work. New gear, new wheels. My goal, raise the fuse at least one full inch.

I've got a watt meter. I'm going to break that out, see what's happening with that. The bird lept off the ground in about 20-30 feet with the 11x6. If the motor can handle a 12x6, I might be aproaching VTOL!

It is my hope to finish the landing gear mods this evening.

I have a electrical question. What are the effects of a prop being too small?

As my previous posts have indicating, I'm *****g out the voltage for which the motor is rated. But if there isn't enough prop? What happens?

I hope to report back here later tonight or tomorrow my Watt meter's findings. I have aquired different sized props. I now have 11x6, 11x7, 12x6, 12x7, and 12x8 (I think) props. I even have some 13 inch props, but I can't remember their pitches.

Which ones should I test, and what numbers should I be recording? I presume I should take all measurements at full throttle?


TIA

Lyndon

Hi, with my experience I suggest you start with the 12 X 8. This prop with your higher voltage should be within the work load and heat profile of the motor. Norm

OK.. I finished my landing gear modifications. With the mods, the 12" props have just under 3" of ground clearance.

Anyway, here's the info

Propsize Wp Wh Vm Ah V W A
11x6 832.5 8.0 17.45 0.871 20.03 715 40 (Master Airscrew prop)
12x6 815.9 2.3 17.25 0.313 17.3 714 41.0 (APC prop)
12x8 821.9 4.7 16.85 0.486 16.92 745 44.81 (APC prop)
12x10 1035.0 0.5 16.23 0.785 16.5 845 52.5 (APC prop)


I tested the props in the order listed. I would run the throttle up to full throttle to read a number, then idle it down for a few seconds, then repeat until I had all the numbers recorded.

Working with the 12x10, I noticed that after about 15 seconds of full throttle, the motor shutdown.

I did all the tests on one set of batteries. I can recharge the batts and try a specific prop again.


So... Having this information.. What prop? and Why?

TIA

Lyndon

Another thought, a 12 X 10 prop has a lot of pitch and it may be like trying to drive your stick shift car from the curb in high gear, it may take a long time to get enoujgh speed to take off. That is why full scale high performance aircraft have variable/constant speed props. You take off with in your case with a prop like a 13 X 6 (low gear) and then when you get up and in the air you put the prop in high pitch your 12 X 10 (high gear) and away you go. My full scale SNJs (Texans) would barely taxi with the prop in high pitch. I used to use wood props on my 1?4 scale models with gas engines with a variable pitch 18 X 6-10. When the engine was pulling such as on take off it would act like a low pitch and then when in the air and the blades unloaded it would act like a 10 pitch. I believe that Zinger made them. Norm

After some more reading/posting. Somebody pointed out that I was *****g out the 40 Amp ESC. That would explain why I had engine cut-outs.

Friday I stopped at the LHS and bought an E-flite 60 motor, 80 Amp CC ESC, and a couple 15x10 props. MotoCalc said this combo would work. I went to work and ripped out my original motor mounting and got the new motor mounted. (When I first built the airplane, I didn't know stand-offs existed.)

I didn't get a chance to go flying Saturday. Bad weather.

But I wasn't really happy with this new motor setup either. I felt it's "too much." I'm sure the plane will fly with it. But I don't really like it.

I fired up MotoCalc again, and looked at Ray's setup. That looks like it has more potential.

Today, I ordered a rimfire 42-60-480. It is very close to a 4120/18 like Ray's but is $50.00 less. I thought I'd give it a try. I ordered it "express shipping" and should see it before the end of the week. Hopefully I'll be able to fly this configuration next weekend.

I wanted to add a final update on this project.

I received the rimfire motor and props, and installed them Thursday night. Saturday it was windy, but eventually, the wind died down, and someone at the airfield was willing to take it up, and I could get some stick time.

The new motor/prop flew the plane very well. We flew for several minutes (we didn't time it) and I got significant stick time in. It took off great, it looped from level flight, climbed, turned, everything I wanted it to do. When I got it home that night, the batteries had consumed less than half their charge.

I'm very happy with this combo so far. Now, if I can only get more stick time before the snow flies.

Final configuration:

Rimfire 42-60-480 motor
Castle Creations 80 Amp ESC
ThunderPower 5S2P 4200mAh battery (3S2P in series with 2S2P)

As for the Eflite motor.. I have a Senior Telemaster on the building board that needs a motor...

And the old motor??? Hmmm.. I think I'll get a second one, and bash a second STM into a twin....

hey VMS:

I'm glad you are having success with the LT40 and the rimfire motor. Try the two servo wing with flaperons if the LT40 is too fast on landing or if it wallows into the air, about 10 to 15 degrees down flaperon is worth trying. Retract the flaperons for normal flying.

ciao -rjf

ps: I changed my LT40 to a tail dragger with a LG from www.TNTlandinggear.com
This works great and reduces drag considerably. -r

Since some of us here are on 5S set ups with AXI 2826/12 motor, I just wanna ask about using the same motor and batts for a 12x10E prop on a WM Super Sports 40 ... should be good right? AUW is about 5.5 lbs.

If you look at one of my previous posts, there's a chart of tests from various props. The last test had 12x10E prop. Notice it drew 55 Amps at full throttle.

The problem was not the AUW of the plane, it was that at full throttle, the motor/prop drew more amperage than it was rated for.

I think the 11x6 prop was just barely within the ability of the motor to spin it. I actually flew my plane with the 11x6 prop, and a 4S (four batteries in series). I'm still new at this so take my thoughts we a grain of salt... I think an 11x6 on a 4S, or a slightly smaller prop, like a 11x5 or a 10x6 would pull a 5.5 lb plane very well, and not max out the motor. Fire up the motor calculator program of your choice and see what it says...



Good luck

VMS - thanks for the reply. I put on the Plettenberg Orbit 25/18 last night and with an APC 12x10, I could not tach her but I got abour 580W. Hmmmm ... the plane did not feel like it was pulling that hard. Will see what the tach says today.