Maiden Flight, combo kit under powered????

[msprygada]

OK, finally got my Yak kit together and we got some decent weather for late fall in Michigan (Sunny (no snow), 50 F, winds about 5 MPH out of the south) and I was able to skip out of work early for my maiden flight with the new Yak.

Here are the specs

Yak 54 Combo
Hyperion HP Z2213-20 motor
Hyperion 20A ESC
10 x4.7 prop
CellShield (low voltage cutoff)
ThunderPower Pro-lite 1320mah battery.
CellPro 4S charger

2 Batteries fully charged, set the CG to about 3.5.

I powered to about 1/2 throttle and the plane moved about 2 feet and jumped into the air. Very nice. I keep a slow steady climb to about 50 feet, circled back and did a level fly by. I had it at 1/2 throttle and then moved to full throttle and the plane did not seem to move much faster nor did the motor sound like it was spinning much faster. When I do this with my Combat Wing with Nimh's, there is a big difference between 1/2 and full throttle and the plane moves much faster and the motor definitely sounds like it is spinning twice as fast. Where I did not notice this with the Yak. So I was flying around at 1/2 throttle getting a feel for the plane and after only 5 minutes, the plane sounded like it was already out of power and had a hard time climbing and vertical climbing was not feasible. The plane sounded like it was only at half throttle so I tried to give it more throttle and it was at full throttle. If I tried to move the throttle back any, the plane felt like it was going to stall and became very sluggish.

Now this is my first experience with LiPo's, but both of them died pretty fast (less then 10 minute flights, more like 7 minutes). Are they that susceptible to 50 degree weather? I took out my Combat Wing today too and the Nimh's lasted just about as long as they do in warm weather with 20 minute flights with being at 1/2 to full throttle with a BIG difference in the motor speed and the plane speed between 1/2 and full throttle, but not the Yak.

Is there something else I am missing here? The weight of the plane should be around the claimed build weight (don't have a scale to test yet) but I would have to say as it flew today, it was under powered. If someone were to want to do any 3D stuff (which I can not do yet), you would be out of power to do any vertical stuff in less then 5 minutes. My plane did not move forward with the authority that the planes do in all the videos that I have seen. It almost seems like something is really wrong here.

Any thoughts, comments, suggestions? I like the way the plane flew, but I am pretty disappointed with the power as is.

Thanks in advance.

[Jimv]

There could be several potential problems worth checking.

1. Is the rear of the motor shaft or collar rubbing on the motor mount? The motor needs to turn freely. I've seen this affect performance.

2. Temperature does effect performance, but nowhere to the degree you mention. Make sure the fully charged voltage is around 12.5 volts. What size packs are you using? Also what is the C rating?

3. Check the throttle end point on your radio. You may not be getting full throttle on the motor.

[msprygada]

There could be several potential problems worth checking.

1. Is the rear of the motor shaft or collar rubbing on the motor mount? The motor needs to turn freely. I've seen this affect performance.

2. Temperature does effect performance, but nowhere to the degree you mention. Make sure the fully charged voltage is around 12.5 volts. What size packs are you using? Also what is the C rating?

3. Check the throttle end point on your radio. You may not be getting full throttle on the motor.

The Thunder Power batteries have a 20C rating. They are fully charged with a CellPro 4S charger. They are at about 27% full when I put them on the charger after the short 5 minute flight. I weighed the plane today and it came in at 19.8 oz. I will check the motor mount but it is attached to the rear of the motor and it can only be put on one way. The throttle servo travel is at 100% (radio default) travel as suggested by Hyperion. I do have access to a timing strobe light which I could use to check if adjusting the throttle servo makes any difference in top end speed.

Today we timed it and it was about 3 minutes of usable power before I had to keep it at full throttle just to keep the plane in the air and had to bring it down before 5 minutes.

I borrowed a friends 2100 Thunder Power battery and this got me about 5 minutes of power before I had to bring it it. My flying buddies thought that the plane was under powered.

[Mikey]

What is the tempature of the motor when you get done flying? Several of the videos that I have shot were with that same motor. Try a brand new battery that you know is good. Take the low voltage cut off out to see if that fixes any thing. But other than that we have the same setup and as you said my planes had plenty of power as you saw in the video. Try those two things and let us know what happens. No mater what paul will make sure at the end of the day you leave happy.

[msprygada]

What is the tempature of the motor when you get done flying? Several of the videos that I have shot were with that same motor. Try a brand new battery that you know is good. Take the low voltage cut off out to see if that fixes any thing. But other than that we have the same setup and as you said my planes had plenty of power as you saw in the video. Try those two things and let us know what happens. No mater what paul will make sure at the end of the day you leave happy.

Well, I did make one flight with the CellShield out of the circuit, and it did not make any difference. If the weather cooperates tomorrow, I will try to check the temp of the motor right after the flight. I think we have a laser temperature sensor at work I can grab on the way to the field.

I have used both of my brand new Thunder Power 1320's that I bought as a combo kit plus used a buddies ThunderPower 2100 and the 2100 only gave me 5 minutes of power before I had to land the plane.

I like the way the plane flies, I am just not happy that the battery only lasts for 5 minutes and that is mostly doing level flight with a few loops thrown in. If one were doing any 3D stuff, you would be out of power in 2 minutes.

[Mikey]

Going to have to say that if you are using new batteries and the power is still not there send the motor in for a replacement. The 2100 should do 5-7 min with the throttle WOT the whole flight. The 1350 around 4-5 with it pinned from take off to landing. That is never moving the throttle from wide open BTW this will kill the 1350 packs.

[msprygada]

Well I did get out on Sunday. I did remove the CellShield but am not sure that it did anything different. I don't fly WOT all the time. I try to keep it at 1/2 for as much as possible because it makes the batteries last longer and if you need WOT to maintain level flight (other than just going fast), then there is something seriously wrong with the plane design.

I did not actually measure the flight times but they were about the same I quess. And now it is supposed to snow within the next couple of days around here, so flying is basically done until the spring. I guess I will have to get a watt meter and play with different props and maybe some larger batteries over the winter.

I guess that I am just disappointed that I have a Combat Wing that is much heavier with brushless 400 HiMax motor running 2000 Nimh that runs for 15 to 20 minutes no problem while varying the throttle from 1/2 to full the whole time and I have a lighter plane with batteries that are supposed to take a higher drain for longer periods and it can only stay aloft for 5 minutes. And few more with a larger battery.

Any additional ideas would be greatly appreciated.

Thanks in advance.

Matt

[paulg]

Their is no problem with the design of the plane in anyway..... please call me 732.910.2269. I will try to figure this out with you.

[msprygada]

I never said there was a problem with the plane. I think it is really great design. It builds well, it flies great, looks great, and I really like it. In fact I am waiting for the Biplane to be available so I can have an indoor plane. Everyone that seen it really liked the design, the looks, and how it flew.

Its just that with the current power system, it only flies for about 5 minutes of usable power where it flies with authority. After that, the plane at full throttle barely has enough power to keep it flying. Even when I borrowed a friends fully charged 2100 Thunder Power battery it only flew for about 7 minutes before it was out of power. And I do not do any 3D stuff (skills are not there yet). Of the 5 minutes of flight, I would say that I am at full throttle maybe 20% of that 5 minutes (doing some vertical climbing). Maybe there is a possible problem with the motor? ESC? Weather too cold (50 F)? Is this the typical flight times for LiPo's? This is my first experience with LiPo's so I am not sure what to expect. I guess from what I read that LiPo's were supposed to be lighter, have more power, and have longer flight times than Nimh. I have read where guys can have 30 minute flight times. But maybe I misread the LiPo information and this is just typical LiPo operation?? If it is, then it is what it is and I guess I just buy a whole bunch of batteries and fly like crazy for 5 minutes, come down and put in a new battery and fly like crazy for another 5 minutes. All in all, I still love the plane.

I will call you tomorrow if I do not get buried at work.

Thanks for your support. Great planes, great service.

Talk to you soon.

[paulg]

ok, please call so we can get you a fix, if need be I will exchange your motor for another. I want you to be happy.

[msprygada]

OK Paul. Went to fly my plane indoors Sunday night and a guy there was real helpful with my plane. He had a watt meter so we hooked it up and here are the results. 214 watts at 20 amps. This was with the 10x4.7. Then he had a 11x4.7 and that pulled like 275 watts and 26 amps. How does fit with what you have tested for this motor? Is it about the same?

The plane was flyable at the university court, but was only able to do (or should I say brave enough) to just fly around the perimeter of the room in level flight. I think I talked to you and you said the Biplane would fly much slower? If so, I think that I would like to get that one for indoor flying when they are available. When will those be available? Any projections yet?

Thanks,

[Mikey]

That is about right a little on the low side I think I got around 240 watts but that might have been with the 9X6. I can’t honestly remember. If you need more power go with the Axi 2217/16 that will do the trick. I have to say you are in the minority that thinks the plane does not have enough power with that motor. Nothing wrong with that.

[Mikey]

I think he is taking pre orders for the first run of the Byp if he has not sold all of them yet.

[msprygada]

That is about right a little on the low side I think I got around 240 watts but that might have been with the 9X6. I can’t honestly remember. If you need more power go with the Axi 2217/16 that will do the trick. I have to say you are in the minority that thinks the plane does not have enough power with that motor. Nothing wrong with that.

I guess I was saying it was underpowered because of the short run times. It would seem that if you were not pushing the plane and motor hard, that you would not drain the battery as quickly, providing that the battery is of sufficient size.

[tdarst]

I guess I was saying it was underpowered because of the short run times. It would seem that if you were not pushing the plane and motor hard, that you would not drain the battery as quickly, providing that the battery is of sufficient size.

I have the Hacker A20-20L with a Castle 25 amp ESC, and 3 cell 1320 TP's on an Edge 540. At half throttle (a little less early, a little more later), the plane will hover, and I can pull straight up out of a hover and climb straight up until I am scared of losing sight of it; in other words - there's LOTS of power. If I fly an entire pack at half throttle until the Castle kicks in the low voltage cutoff, that takes 12 to 14 minutes. I routinely fly 8 to 10 minutes using the throttle as I see fit, around half most of the time, full and closed for short periods during various manuevers.

There has to be something wrong either with your motor, ESC, or the wiring/connections inbetween. Did you ever get this resolved? If you didn't call Paul... you should. He's a great guy, very knowledgable... and above all - wants you to be happy... VERY HAPPY.

TD