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Jul 16, 2019, 04:26 AM
RobKit--Sweden
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I will re check but have to get 2 identical spirit level.
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Jul 16, 2019, 09:59 AM
☠ -4º
freddy_fo's Avatar
You probably already know this but err on the side of caution or nose heavy Pitts can be very unruly in tail heavy situations with the relatively short wing span and short tail moment.
Jul 16, 2019, 02:02 PM
RobKit--Sweden
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Quote:
Originally Posted by freddy_fo
You probably already know this but err on the side of caution or nose heavy Pitts can be very unruly in tail heavy situations with the relatively short wing span and short tail moment.
Its great to have your comments, it makes me think ahead a bit more..
I have no experience of this type of airplane, so not sure at all what to expect with the CG on 118mm and a "possible " -1/2 to -1 degree down stab,, however I suppose any tail heavy airplane have its own will,, more or less. The question is how much to move CG forward, if at all considering the minus angle on the stabilizer.?
Jul 16, 2019, 02:49 PM
☠ -4º
freddy_fo's Avatar
I'd go for 0. Even at 100mm cg it flies better than being too far back. The problem for you is your level looks big enough to throw off the reading if you placed it on the tail. What I'd do with the plane on the balancer is mark a stationary reference point of where the h-stab is at when it's level. Maybe set the tail next to a wall if possible, place the level on the tail and move it up or down by hand till the bubble is centered, mark that point on the wall next to the stab then remove the level and let go of the tail. If the tail returns to that mark at 118mm you are good. If not add or remove weight till you are close. I'd favor the tail being a little higher than the mark rather than a little under.
Jul 16, 2019, 03:08 PM
RobKit--Sweden
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Quote:
Originally Posted by freddy_fo
I'd go for 0. Even at 100mm cg it flies better than being too far back. The problem for you is your level looks big enough to throw off the reading if you placed it on the tail. What I'd do with the plane on the balancer is mark a stationary reference point of where the h-stab is at when it's level. Maybe set the tail next to a wall if possible, place the level on the tail and move it up or down by hand till the bubble is centered, mark that point on the wall next to the stab then remove the level and let go of the tail. If the tail returns to that mark at 118mm you are good. If not add or remove weight till you are close. I'd favor the tail being a little higher than the mark rather than a little under.
I see how you mean and it seem like a simple way of establishing a good cg according to the stabilizer, my plan was to get 2 sensitive very small/light spirit level and put one inside beside the rx and one at the stab then I suppose I can get a good enough comparison and from there know exactly how much the stab os "off".,,, if I remember correctly,, it is a 2-3mm movement of the tail to center the bubble, so I dont want to think its a big deal, but want it perfect anyway.
Jul 16, 2019, 03:58 PM
☠ -4º
freddy_fo's Avatar
The level I use came with my Great Planes CG balance machine. It's just a thin piece of lexan with a tiny bubble level/tube you stick to it. Hardly noticed on these larger planes so one doesn't have to compensate.
Jul 19, 2019, 08:43 AM
RobKit--Sweden
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Quote:
Originally Posted by freddy_fo
The level I use came with my Great Planes CG balance machine. It's just a thin piece of lexan with a tiny bubble level/tube you stick to it. Hardly noticed on these larger planes so one doesn't have to compensate.
Gentlemen, thank you for all your support, tips & tricks.

I got some 2 gram level and think I have been able to confirm the 118mm CG.
So now I am waiting for the winds to calm down.
Jul 19, 2019, 07:48 PM
Registered User
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I've been flying the snot out of mine lately . 5s 3000mah. it's been pretty good . then I threw in a 5000mah 5s 50c . and it felt slightly heavier . but didnt throw if CG at all. couple trim clicks between 3000 and 5000mah. I'm loving this plane now.5000mah is the perfect size. no way a 5000 6s would fit on the tray. this barely fits .I fly it steady around 60% throttle and it's pretty fast. good vertical . but when I hit 85-90% it screams. I use to only fly it once and a while. now it comes with me every time and I pound 8 packs thru it every time.
Jul 20, 2019, 02:19 AM
RobKit--Sweden
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Quote:
Originally Posted by doug14
I've been flying the snot out of mine lately . 5s 3000mah. it's been pretty good . then I threw in a 5000mah 5s 50c . and it felt slightly heavier . but didnt throw if CG at all. couple trim clicks between 3000 and 5000mah. I'm loving this plane now.5000mah is the perfect size. no way a 5000 6s would fit on the tray. this barely fits .I fly it steady around 60% throttle and it's pretty fast. good vertical . but when I hit 85-90% it screams. I use to only fly it once and a while. now it comes with me every time and I pound 8 packs thru it every time.
This fits.. but have to go a Sunnysky x3525, 520kv motor with 14x8 prop.
Jul 20, 2019, 08:18 PM
Registered User
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Quote:
Originally Posted by robkit
This fits.. but have to go a Sunnysky x3525, 520kv motor with 14x8 prop.
it must be longer and flatter. cause mine just fits.
I'm running a 4120/12 850kv cobra with a 13x6 prop.
Jul 20, 2019, 08:24 PM
Registered User
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these are some numbers I pulled from testing.
I hit 1846w ...whoops .

turnigy 4240 740kv
70 amp esc
4s 13x10 55a887w
13x4  38amp 590w
14x7 57amp 879w
13x8 54amp 847w
67amp 5s 1160w storage v
79amp 5s 1531w full
motor spec
4220 740kv 215g 870w
4258 650kv 288g 900w

850 cobra 1110w 4s 75amp 293g
4s 70amp esc
12x6 54amp 800w
13x8 78amp 1040w
13x4 50amp 700w
13x6.5 63amp  937w
5s 13x6.5 99a 1846w
5s 13x4 66a 1236
Jul 21, 2019, 08:47 AM
RobKit--Sweden
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What is the max weight you have reached & how was it flying ? ?
Jul 21, 2019, 04:39 PM
Registered User
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I never checked the weight. but it flys fantastic.
my 1st expierence with this plane was horrible.
something wasn't right. either my expectations..or just not aware of the difference between floaty foam electrics . either way I was all over the place. I tweaked a few things. got it decent on 4s with recommend setup . but it was still slow and weak. I climbed.. tip stalled and somehow lost control. crashed broke cowl and motor box. rebuilt. slapped in a bigger motor new prop and it somehow flew better.
then I bumped up to 5s. now I cranks along fast.
I fly steady flights around 60% ..with an occasional 85% hit . it puts a smile on my face every time. landing has always been a challenge. but I ditched the wheel pants and put a bigger softer wheel on it.
sometimes I land a little heavy and bend gear . but that's the only issue so far. maybe I will weigh it tonight and see what it's at.
Jul 22, 2019, 04:31 AM
RobKit--Sweden
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I would guess that we who are used to fly foamies with a completely different power to weight ratio, have to actually learn to fly the plane and not only use the throttle. But for sure it is very nice to have some extra power and pull out when needed. I have been compairing set ups in e-calc and what ever combinations I use with the reccomended motor (SK3 4240, 740kv) it is simply not enough to provide that extra in order to keep me relaxed it would actually need to be a 6S set up with a 500kv motor at about 1500W turning a 14x8 prop, I suppose it have to be a tradeoff between power and weight.. I have not yet flown mine hoping to get it in the air this week.
Jul 22, 2019, 11:47 AM
Registered User
This is a great arf. We need some good pitts arfs since many manufacturers discontinued this plane. I maidened my Pitts a few weeks ago. Got about three clean flights in with just a little trim to the ailerons and just a few clicks on elevator. Mine runs on 5 cells with Rimfire .55 setup and 15 X 8 propeller. I am thinking of switching to 15 X 10 for a little more power if the motor can stay reasonably cool. I was running an electrifly 80 amp speed control that tower used to sell, and during my fourth flight the throttle became inconsistent. The plane ended up tip stalling into a hay field. Just a few cracks in the cowel but no other damage whatsoever. I am impressed with the quality of the build. This is definitely my favorite plane and I may need to snatch a red one to have a spare! After gutting the plane for new electronics, it flew near perfect this past weekend, and I got a lot of comments from fellow fliers at my club. I learned a lot from everyone's testimonials on this plane.


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