Elevator Suggestions

[tdollmeyer]

Could not wait to get my Parkhawk in the air this morning. Pulled back the trim like the instructions said and launched. If this had been a plane it would have stalled. I had to hold down on the elevator during most of the flight even after putting the trim back at neutral. When I set up the linkage the way the instructions indicate I had way more than 25 degrees at center stick. When I repositioned the arm to straight up and down at center the tail looked to be closer to 25. I am going to measure it later to see what it really is. It seems that something is wrong with it being so far off when I first set it up. Am I supposed to increase my throw like on the tail servo? I also noticed after getting things set up that I had installed the servo so that the output is on the left side. Will this really matter?

Aside from the above, this thing is really cool to fly. I suspect I might be lacking on the climb rate but I want to see how it does after getting the elevator correct. I might have been flying with too much drag.

Terry

[eflyer1234]

Terry,

You do not have to worry about which side you have the servo output on. The bird could care less. :-)

The tray and servo arm should be set up so that the tail is at the 20-25 degrees when neutral. Some of the packaged elevator arms may be too long or short for the arm to be truely vertical. You also do not have to extend the throws. Once the bird is trimmed out, you will find that you can get all the elevator throw you need from the trims alone. I almost never use elevator except to tighten a turn. I control altitude with throttle.

Please also check your CG. I know this is not well documented, but the CG is at the forward wing hold down. If you have the screw in hold down, attach a string to it. If you have the O ring hold down, you will see a hole in it to attach a string. When balanced at this piont, the nose should hang down about 5 degrees. To help balance it, you may want to position the battery across in front of the rubber bands as shown in the instructions.

Should you have any other questions, just drop me a note.

-Jeffrey

[tdollmeyer]

After I made a template to check the angle I found that the tail was still a little too steep. I set it to right at 25 and flew it last night. I was still flying with the nose what I thought was to high and actually found that if I gave it a little bit of down the Hawk would level out better and fly faster. It would then climb better. Still did not get it more than 30 or 40' up. Was up high enough for me to try a glide. Contrary to the instructions, I thought it glided pretty well. When I took it out to fly this afternoon the temperature was a little over 90. The vertical performance was definately down. I think at this altitude that the Parkhawk as set up is right at the edge of it's flight envelope. I have some 720 NMh 11 cell packs for my IFO. Will this be to much for the mechanics and wings?
I also noted in a previous post about adjusting the ball links to change the climb rate. I thought I might try that. I do not plan on going beyond the angles that where posted so I figure I should be safe.

Terry

[eflyer1234]

Some things you may want to try is to lower the tail angle to 20 degrees. That will help you some. An increase of the nose weight for balancing may also help here. Then you can always play with the ball links...

The birds mechanics can handle another cell, however you will be on the edge of what the motor can take and have to also watch your speed control.

As far as the glide, I personally think it is not the best, but then again I compare it to my full house unlimited ship. :-)

-Jeffrey

[KeithK]

Terry,

Do you really mean 11 cells? Were you using the "stock" 8-cell pack for your tests? Did you break-in or time the motor? What altitude are you flying at now? Going to the Silverthorn meet? Whew, lots of questions. Hope to get mine flying soon. My theory is that since my PH is all black, black absorbs light, Colorado has plenty of sunshine, I shouldn't need to turn the motor on :cool:


hope to get mine flying soon (at 7000ft)
Keith

[tdollmeyer]

The reason I am thinking in terms of 11 cells is because that is what I fly on my IFO and already have a couple of battery packs made up. I would only try that if all else fails. Once I got my tail angle down to about 20 degrees with my trim the Parkhawk then flew faster and climbed better. Even got to try some gliding. That was at about 7:30 pm and 80 to 85 degrees. The next day when it was about mid 90s it did not climb quite as well. Still trimming and waiting on low winds. Don't know the altitude, just that it is higher than Denver.
Yes I will be at the silent fly on the 27th and 28th.
I have never timed a can motor. I also am not inclined to do any break in nor retiming when a model arrives already mounted unless the instructions tell me to do so.
My main concern with trying more cells is that without some sort of change in the gearing that I could pull too many amps for the motor. I am also using the GP 10 Electrifly speed controller and would have to change it in order to try more cells.

Terry

[niek]

Eleven (!!) cells, (> 12V !) will be far to much for the sp300.
8 cells (at 7 amps) is at its limit already.

And you will add much weigth with 3 more cells...

[eflyer1234]

eleven cells would be too much, my earlier post alluded to going to 9 cells, and that is pushing it too.

The max current for the motor is 13 amps and that is being generous. I would be carefull trying to push it much further.

[niek]

At 13 (??! do I read this right?!) amps the motor is no longer functioning as a motor, but as a smoking glowing heater... which something that looks like an axis turning in it.

Above the 8 amps, efficiency is detiorating [very] fast with the sp300.