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Pat
I capped this from a much earlier post a bunch of pages back, the 'recommended' range falls from the rear upper wing bolt to about the point on the decal, depending on how accurately the decal is positioned I suppose, but you're safe in that half-inch or so range ahead of the rear bolt WestTexasKing reported flying one with the CG as far back as actually behind the trailing edge of the upper wing and pointed out there's a very wide range that the little Pitts can handle, depending on how squirrely you want her to be Dusty |
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I don't think it was very practical LOL |
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Best Regards, TwistedGrin |
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TwistedGrin referred to it as the "Monahans Maneuver", is that your official designation or is that still undecided? I'd love to see video of that stunt in action, that's gotta be impressive from the ground just from the description of it! Dusty |
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Yeah, I guess the Monahans Maneuver is good enough
It works just fine all stock, with CG in normal ranges, no special modifications necessary (except for maybe full throws with stock components). If I had mine going right now I'd shoot a video, but it's all over the table right now getting some extra attention (I say that, haven't touched it in weeks...too busy cropdusting!) It already has a radial cowl on it, but I'm trying to recreate the Samson look: Needs longer gear and a single seat cockpit, so I'm redesigning the landing gear completely with slightly larger wheels and pants, so I'll get quite a bit more clearance for a bigger prop. The belly is going to be shaved flush, instead of having it droop down below the wing, like this: Paint is in the works too, but it'll be a cream/red 30's era look: Going to use one of hobby lobby's scale two blade adjustable pitch props to finish out the classic radial look: |
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Thanks so much for the info
You guys a great!!!!!!! |
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WestTexasKing - I'm with GreedyG on that, can't wait to see it! We'll be expecting pics of course!
After seeing 69SuperBee's "Art Scholl Pennzoil" livery back on page 136 (post #2026), and FatherGoat's new scheme on page 144 (post #2154), among others, seems like this little Pitts just loves to be dressed up for a night on the town and she still looks like a million bucks in every outfit! I guess I'll stop worrying about mine shedding her decals bit by bit with each flight and start thinking what NEW colors she'll look great in when she inevitably comes back a blank canvas Pat - You're more than welcome! There is a veritable ton of great info and tips throughout this entire thread, but it does get a little tedious scanning back thru page after page trying to remember where you saw any particular nugget of wisdom, I've been tempted more than once to just start over way back at the beginning and take notes on every little relevant or interesting hint and suggestion to keep track of them all for future reference This lovely little Pitts seems to never actually reach a 'finished' stage, there's always some other cool little upgrade/mod/fix to try out on her next! Dusty |
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I want to refraize my question
Did you guys have to add a bunch of weight in the cowl to get the cg correct 1/2 inch forward of the rear bolt Seems I would have to add a substantial bit of weight to make it work Thanks in advance |
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Pat
With just the stock parts that came outta the box, with the battery in the forward compartment behind the firewall, and the ESC tucked in there beside it, my CG fell very close to the rear bolt. I don't know precisely where actually, I hooked a finger under the trailing edge and lifted her by the bit of threads of the rear bolt that comes thru the mount, and she hung there in a maybe 10-12 degree nose-down attitude. I figured that was close enough for gov't work, somewhere ahead of the bolt would make her hang level, so I was good to go If you need to move your CG farther ahead, I'd suggest the easiest way would be a larger battery, quite a few others use 1800mAh-2200mAh depending how heavy they want her up front, most report it helps her penetrate any prevailing wind quite nicely over the lighter 1300mAh battery she comes with edit/add/p.s: If you decide to move up to larger capacity batteries you'll start to run into problems with getting them to fit, somewhere in this thread they detail a mod that entails cutting a forward section of the floor of the rear plastic compartment to allow sliding the battery up and in diagonally toward the firewall, so the 'easy' CG adjustment doesn't come without caveats Barring that, then some small bits of lead up front on the firewall behind the cowl might help you get started then adjust from there... normally inside the front of the cowl would be better, the farther forward you get it the less overall weight you need, but this cowl is notoriously fragile so I wouldn't recommend any extry weight in there to risk the eggshell cowling in the event of a harder-than-expected meeting with the ground good luck with it! Dusty |
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Last edited by S4WDU5T; Jun 01, 2012 at 07:35 PM.
Reason: clarification
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Thanks Dusty
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I lost rudder servo in flight during a cross wind landing....I have had to replace both the elevator servo and the rudder servo....I think I stripped the gears of those original servo's by setting the control rods in the most inside holes of the control horms...and the control surfaces were still tight after seemingly hours of excersizing and finally scoring the hinge area's with a razor knife. I have added three motorcycle wheel balance wieghts to the plane, two on the forward battery hatch door and one on the firewall underneath the motor where the cowling covers up the nose of the plane. I do NOT advise putting any weight at all on our cowlings....it just won't hold it and when you land it will destroy the cowling. Glue or tape any weights directly to the planes fuselage. Right now after some minor repairs and getting my COG at least dead on the rear upper wing bolt, my HK sttiP weighs 28.36oz. The two quarters, two nickels and the battery hatch door weighed 24grams and enabled steady flight during throttle and reasonable glide pattern at throttle off. I am flying a GSW 10X8 prop and flew just fine in about 10mpr winds at around 50% throttle after adding the weights. The three motorcycle rim balancing weights and the battery hatch door weigh 23grams giving my bird the grand total 28.36oz. Landings will carrly a little more speed, but I think the bird will deal with the wind much better being a little heavier. My Red Nitro Planes Pitts was perfectly balanced with zero added weight, dead on the rear top wing bolt, and I am using all the parts from it in my HobbyKing Blue sttiP set up the exact same way. So I have no answer to the difference in COG of the HK sttiP. I also found my motor mounts were loose on the bench tonight when I was going through it, one of the three nut and bolt assembly where the motor bolts to the plastic engine mount had half a thread before the tiny nut was to spin off. This HK sttiP lower wing does not meet flush up to the fuselage, so I am wondering if this is causing some of my upward thrust exaserbating the tail heavy flights before adding nose weight. I would rather have a heavier plane at upper wing rear bolt than a lighter plane as the higher weight allows for a greater wind envelope and more opportunities to fly. When the plane has a level glide path with very little altitude loss at neutral stick and zero throttle...it should mean we have a pretty balanced bird. My HK sttiP was suprisingly stable after I added the 60cents to the battery hatch door and held pretty well into the wind. Once in the air the HK sttiP did loops and rolls just fine and coasted into the wind at 25% maintenance throttle, down wind I had to throttle up a bit and bleed off some speed as I squared off the turns for upwind landing approaches and low speed passes. I still can not get used to the silence of these planes, flying at the club field on Friday the fellas were chuckling with me that it was so quiet and its speed is decieving. Stiff winds shot me sky up coming in for a landing under a zero throttle glide before I added the 60cents....I am discovering a light power throttle is best for this sttiP landings. Hope to get a second maiden on the minor repairs one day this week, tomorrow the winds are 17mph and above...too much for me to enjoy. TwistedGrin |
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Speaking of total weight....I wonder what weight some of you other Pitts/sttiP flyers have in the air. Is my 28.36oz on the heavy side or just in the middle average weight?
TwistedGrin |
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TG,
My 2 re-build one's maybe not a good ref. here are weighting respectively: NP one = 21.60 oz. no cowling heavier LG bigger wheels xtra glue. HK one = 20.46 oz. as NIP rebuild 99 % stock. ..and these figures are without lipo's...and I am sure I am on an "average weight" and no problem to get in the air with 11 x 8 SF prop. Hope this help. |
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Mine doesn't weigh anything in the air
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