500 protos CoG problem

[danhampson]

took the protos to the field this morning planning on doing some FF so i had a bit of a warm up with my 450 pro, all was well. i did some lovely banked turns and and FFF (for the 450). After 2 packs i was feeling confident and got the protos ready for flight. i started with some hovering side in, tail in and shaky nose, I returned to tail in and pitched the protos for FF.
so i flew away from myself and turned to the left and it just kept accelerating after a couple of banked turns it was starting to go too fast for me to keep up with, I lost and regained orientation a couple of times and very nearly ploughed the field. in the end i won the fight and she came home i one piece (thank god).sorry guys no video my camera man couldnt keep up (yes it is that fast)

But the problem i have is when i purchased my protos i got 1 battery, a 2950mah which is throwing the CoG out. Ive mounted the battery as far back as i can and without the canopy its level but when the canopy is on there is a couple of degrees forward pitch.
I was planning on getting a stretch kit for it which will balance it out but in not able to order it until the end of june (fun money spent on the protos).
I was wondering if its ok to use the trims on the tx to balance it in the air, the protos is FB. And is there a way to slow it down.

throttle curve 0-70-70-70-70 2250-2300rpm
pitch 0° 2° 2° 6° 12° These are wrong
Pitch -2° -2° 0° 6° 12° (right)

 

[Tony]

Pitch in normal mode should be somewhere around -3 -1.5 0 5 10

That will allow the heli to stay on the ground in the wind. If you get a decent gust of wind with 0 degrees of pitch, it could lift off or tip over since there is nothing forcing it to the ground.

One way to slow it down is to lower the HS. Something like 2000rpm should work.

Unlike airplanes, CoG is not as important on helis. don't get me wrong, it's important, just not "AS" important.

When you put it up into a hover, it should be trimmed out to stay in one place. Well, as well as a ccpm heli does anyway. If you trim it to pull back, then you will be fighting it in flight to keep it going forward. Only trim just enough to keep a level hover.

 

[danhampson]

thanks tony they were suppose to be -2° not 2° ive tryed to measure the angle of forward pitch and i get it at about 2° but it could be more because themeasurment was done with an app on my phone

 

[Tony]

One thing to make sure of is that you have 0º of pitch at mid stick. That way, when you are ready to go into idle up, there will not be any major climbing or dropping of the heli. Only small collective adjustments should be needed.

 

[danhampson]

my pitch in iu is linear and ive not change the throttle yet just because i dont use iu yet. island breeze said he runs 1800 in normal and 2150 in iu but his are stretched use 470mm blades.
do you think that those speeds would work running 425mm blades?

 

[Tony]

That I'm not sure of. I will let those with a 500 answer that one.

 

[danhampson]

thanks tony, it was scary im still shaking now, i flew my last pack on the 450 after my near crash experience and was throwing it around (sport ish) for fun, the 450 seems really slow compared

 

[danhampson]

ive been playing with my throttle curve and 0-45-45-45-45 gives me a HS of about 2050rpm (audio tacho), ive heard that the yge ESC doesnt like going below 40% so i thought that 45 would be a safe bet, im hoping to get her to the field to test the HS.

 

[Island Breeze]

ive been playing with my throttle curve and 0-45-45-45-45 gives me a HS of about 2050rpm (audio tacho), ive heard that the yge ESC doesnt like going below 40% so i thought that 45 would be a safe bet, im hoping to get her to the field to test the HS.

I never ran the ESC with default settings, so I wouldn't know what or how it feels like. I used the program card and is set with GOV mode, with that said my throttle curve are at normal: 0-63-63-63-63 and IU1 I am at 70 straight. 2200 HS seems way to high, if that 2050 is your normal than I can imagine what your IU sounds like. my 1800 is just to get me off the ground and for auto landing. the 2150 for me at least is a good sport and mild 3D setting. if 40 is your max low setting then try normal at 0-43-43-43-43 and IU at 45 straight. go into a hover and flip that switch you should hear a change in motor RPM. as for your TAC, I am not to sure how accurate it is. Gather all your info on what the default esc puts out, your gear ratio and calculate from there. they do have great headspeed calcs out there that can give you your baseline. Help me fells..i believe one would be Mr. Mels HS calc. forgive me at my age if you haven't use things for awhile you tend to forget..LOL good luck and check back with your results.

+1 for Tony. you should lower pitch until you get use to it. I run straight 11 on pitch and full 10 on cyclic. I also up my gain/agility on my ikon banks. this bird is crazy fast and agile.

 

[danhampson]

ive taken her back to the field to test the 45% throttle curve out, and the head speed was too slow. so i knocked it up to 55% and did some short forward flight and returned, it was alot more manageable than before. I will give 63% a go tomorrow.
Ive trimmed the forward pitch out (3 clicks), i think it was the pitching forward that messed me up more than anything.
Dont get me wrong this bird is amazing i just think that i have to get used to the speed, it was a complete surprise and it has brought my 450 flying on, to the point where im seriously thinking about trying a loop (do them on the sim all the time just havent had the bottle)
Your right about it being crazy fast and agile, its like the Lambo of helis.

 

[Tony]

Glad you got it trimmed out. As stated, it's not a problem with a flybar heli to add some trim. On a flybarless, you will just let the gyro do it's thing and the CoG is a little more important. Now, we just need video!!!!

 

[danhampson]

lol. ive got video from this morning, well video of trees and sky and a very very quick flash of heli. My camera man gave up, swearing and saying he cant keep up with the thing, then i was swearing saying i cant keep up with the thing, lmao.
We will get some video of it this week at some point, once i can tame the beast.

 

[Tony]

It's all good, I know how it can get sometimes. There have been videos that I have shot that I couldn't post because it would be nothing but bleeps hahahahaha.

 

[danhampson]

been to the field and tried 63% throttle and its awesome enough power to move about and not to get bogged down but not to much so that she takes off like a rocket ship. i tried 70% too but it was a bit to much for the moment, but i think with so practice i will get used to her. God i think im in love.

 

[Island Breeze]

been to the field and tried 63% throttle and its awesome enough power to move about and not to get bogged down but not to much so that she takes off like a rocket ship. i tried 70% too but it was a bit to much for the moment, but i think with so practice i will get used to her. God i think im in love.

Practice! Practice!...you got to love it huh! i still have some shake when i fly her and i just experienced the worst of it when i flew the GOBLIN. Whew! what a rush that badboy makes some crazy blade farts. LMAO

 

[danhampson]

I got some blade farts out of her, doing some pitch pumps to see if the head speed would get bogged down. i was getting lots of looks off people on the field it was so cool. Tomorrows forcast is good, very little wind and sunny so im hoping to get her out and get some more practice in.
Cant wait to see the vid of your goblin, is it even more insane than the protos?