"Is it me or the plane?"

[Wildblue2u]

I admit that I am a newbie, but I have alittle experience with RC planes, and I am a full scale pilot. I recently built a FT Mini Trainer and I thought I set-up the CG properly, with slight nose down. So I made an attempt to maiden yesterday with a couple of glide tests, which didn't go very far, and seemed to dive towards ground. So my first thought was that since I have the battery installed and within CG that my toss didn't have enough airspeed to over come the weight and it stalled, hence the apparent dive towards ground. So I powered up, face into the wind and tossed again. This time it pitched up, broke left and dived into the ground. I need to fix the power pod some and there a a few crinkles to forward fuselage, but over not the worse for where. Now mind you I am doing this on my own, I work a lot and have little time to drive to the local RC field and hook up with more experienced RC pilot, but I felt I could handle this. Looks like I may be wrong with this assumption. Now I realize that without visually seeing what I am doing and thoughts of what I may be doing incorrect would be pure speculation, but I would appreciate any feedback. When launching a FT Mini Trainer is there some trick to avoid a pitch up and apparent stall right and launch? Is the some trick to CG that I am missing? Should I be a bit more aggressive with the toss at launch to get more airspeed? Any suggestions?

Also, if anyone happens to be on Oahu, Hawaii I'd appreciate a shout out. Looking for FT fans on the island and sources of foam board here. I have check with R L Adams and there are plans to have their products on Amazon. And any attempts to ship Adams products to Hawaii from themrequire a pallet load as a minimum.


Regards,

Don

 

[makattack]

Hi Don,

Welcome to the forums and the hobby! It's hard to say without seeing the model, but two things come to mind that bites both new and seasoned hobbyists... actually three:

1) Did you calibrate the ESC with the throttle range on your TX/RX set?
2) Did you double check the prop is mounted in the correct direction? A reversed prop will still generate thrust, but not enough. Any printed numbers on the prop should face the direction of forward flight (the convex side faces forward)
3) Seeing as you are a full scale pilot, this becomes less of an issue, but you checked the control surfaces are moving in the correct/desired directions to match your TX input as part of your pre-flight?

 

[dgrigor02]

Are you using the 4 channel wing with ailerons or just the 3 channel Polyhedral wing ? Your wing is lined up and parallel the elevator? Nothing looks crooked ? Control surfaces are all as even and inline as possible ? Double checked and triple checked all none of your control surfaces are reversed ?

 

[Wildblue2u]

Control surface are moving in correct direction, prop with numbers to front and spinning CCW, and I dont know how to calibrate an ESC. I have a similar problem when I tried to maiden my Parkzone Radian. It's like the Earth is pulling the model to the ground.

 

[Wildblue2u]

I am using the non-aileron, polyhedral wing. I'll check the wing to horizontal stabilizer/elevator alighnment, as lwell as the control surfaces. So, Hawaii is often windy, and I waited until the winds decreased, say about 10 kts, and I launched into the wind. If I am attempting a simple glide test with battery in and CG set, should I give it a more aggressive toss to give it more airspeed?

Don

 

[makattack]

To calibrate an ESC, *most* will use this procedure (not all esc's are programmable, and some may not require throttle calibration):

1) Remove propeller.
2) Power on TX with throttle at maximum
3) Connect power to ESC
4) After a series of beeps from the motor, indicating the RX has connected to your TX and the ESC is now in throttle calibration mode, lower throttle quickly to the lowest setting.
5) Disconnect battery

 

[Wildblue2u]

Thanks

 

[Capt_Beavis]

where did you put the servos? The TT is notoriously nose heavy and the servos need to be moved back towards the tail and mounted externally or weight much be added to balance it properly. Getting CG right is a little tricky. I have been able to move the battery around a lot on a plane and see no CG difference (it is probably just me). Flying really tells the tale. If the plane won't glide than CG is off. Adjust it for a good glide.

 

[wlouisharris2000]

I've built 2 tiny trainers; aileron and 3 channel. My alignment is off but both of them still fly pretty well and I can adjust with the flight controls. My TT with 3 channel tends to go nose up with full throttle. I use a 7(GWS 7035)inch prop so that may be one reason. Initially I used a 6 inch prop and it flew terribly. All the guys at the field were telling me my cog was off(which I am sure it is slightly)and telling me no way the plane would fly, but once I changed to the 7035 it flew really well. I didn't see that you had the power pod angled to the right; meaning the shorter end is on the right side. Make sure cut the angle on the power pod because that counters the thrust left-ward you get from the natural turn of the prop. I also use a 2300 kv motor with a 2S 800mah battery. So yah, get some photos and you will get some good tips. But yah, like I was saying; the prop makes a huge difference in the amount of thrust you get. Keep working at it. I have similar frustrations with the mini scout.

 

[guitchess]

waited until the winds decreased, say about 10 kts, and I launched into the wind.

Don

I'm a rookie too, so take this for what it's worth.

If this is what you're calling low wind, this is probably the problem. While my Tiny Trainer is one of my better wind handling models, 10 kts is still enough to make it stall out unless you're giving it a good amount of throttle. Not enough throttle/speed was my main mistake when I began.

Also, I've only been to Hawaii once, but it seemed like 10kts winds would be few and far between.

It also sounds like you may need down trim. I don't know how it is on full scale, but on my TT, very minute changes can have severe results, i.e. 1/16in elevator linkage adjustment can put trim completely outside of the transmitter trim latitude.

 

[Wildblue2u]

So I mounted the servos as the build video and plans call for. As for the motor, is it the stock motor from Power Pack A, an Emax, which I cannot recall at the moment the model or size.

 

[Wildblue2u]

Servos are where the build video and the plans called for. I set the thrust angle to the left, again as called for from the plans. I will either repair or rebuild the power pod since it was damaged in the last flight attempt. DTFB isn't available in Hawaii so I am looking at alternatives. I picked up some foam board from Office Max and based on an article I read on the FT website I picked up some Ross foam board at Walmart. The price was right ($0.88/20x30 sheet) and first glance it seems similar to DTFB. Other foam board were either heavier or much more expensive. Adams has told me through an email the DTFB will be available on Amazon soon.

Don

aka "Wildblue2u"

 

[Wildblue2u]

I'm a rookie too, so take this for what it's worth.

If this is what you're calling low wind, this is probably the problem. While my Tiny Trainer is one of my better wind handling models, 10 kts is still enough to make it stall out unless you're giving it a good amount of throttle. Not enough throttle/speed was my main mistake when I began.

Also, I've only been to Hawaii once, but it seemed like 10kts winds would be few and far between.

It also sounds like you may need down trim. I don't know how it is on full scale, but on my TT, very minute changes can have severe results, i.e. 1/16in elevator linkage adjustment can put trim completely outside of the transmitter trim latitude.

The Trade Winds will blow out of the northeast generally most of the time. Typically it is 10 to 15 kts. It makes for cooler weather and generally clear to partly couldy skies. Makes it difficult for light models, but given a slope with the correct geographically orientation (mostly on windward or east side of Oahu) great for slope soaring. As a matter of fact I am also a rated Commercial Glider pilot and when the winds are favorable a simple tow to 2000 ft will give you an all day flight. Othet times of the year we have winds from the south (Kona), which are more humid, overcast, and brings "Vog" or volcano haze from the Big Island. This year, due to the strong "El Nino" effect we have had Knoa winds than usual, with lots of rain, which make RC flying difficult, especially for foam board.

So, back to your point with some down trim may be the ticket? And, should I use more aggressive launch to get higher airspeed over wing and control surface to prevent stall?

DK

 

[earthsciteach]

I may have missed it, but did you say what size battery are you using, both mAmp hours and number of cells?

Assuming all is working correctly and the battery isn't oversized, you may need to shim in down thrust on the motor. Mine balloons like crazy even with a good bit of down thrust dialed in.

I'm quite surprised it stalled if you have it at full power. It should hang on the prop just fine. Aside from the possible thrust angle issue, an overweight battery, an uncalibrated esc, prop on backwards, or motor spinning backwards, I can't think of any reason it would just stall like that.

 

[guitchess]

I would say yes to the more aggressive launch, with very little, if any, upward angle. I really don't know how some of the people I've seen using soft or underhand launches do it. I've never had any success without a good firm toss, especially in wind.

It's hard to say about the down trim without a little flight. Unless your throws are to small, elevator shouldn't be enough to keep you out of the air.

Again, I'm a rookie too, so pros, don't let me give bad advice. I'm just basing it on my short flight history

 

[guitchess]

I'm quite surprised it stalled if you have it at full power. It should hang on the prop just fine.

I've had people tell me that too, but my TT has never even showed the slightest hint of "hang". My Bloody wonder yes, but not the TT. Maybe too much hot glue.

 

[earthsciteach]

I was looking at power pack A and realized my motor has a bit more oomph. Are you flying on a 2 or 3 cell battery?

 

[quimney]

Faster!

I don't have a tiny trainer but I have built and flown a lot of different planes. Some of them really need some air speed to get going, especially if you are new to the sticks.

What really made the difference for me was to start doing a discus launch. I don't spin all the way around but you can get some real speed on it with a good 180 degrees sweep. Funny thing is you don't have to worry too much about being perfectly flat when you release... they always seem to level out pretty quickly if you can get them to start to fly.

 

[Capt_Beavis]

This is a problem. The servos are too far forward with the motor on the plane.

Here is an article on it. I don't have a TT myself but I have two friends that have built them and I have flown both of them. We are teaching one of them to fly on his. They both have the servos mounted as shown.

http://flitetest.com/articles/tiny-trainer-a-little-airplane-to-love

So I mounted the servos as the build video and plans call for.

 

[mybad]

My TT was TAIL HEAVY!

After dealing with a nose heavy TT, I decided to try a 2S 300 mAh battery I had laying around. It was so light that at first my TT was tail heavy! I had to move the little battery forward almost touching the propeller!

IT FLYS GREAT WITH THE 2S 300 mAh battery! It also flys slower!

So, if your TT is nose heavy or just too heavy overall, try a lighter battery.