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Old Mar 31, 2007, 07:11 PM
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Pittsfield, Massachussetts, United States
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Help!
superfreak bat advice

I'm getting ready to maiden my new bat (with the superfreak mods). It will be flown on the front side. It is currently balanced at six and a quarter inches. I have a bat with the predator mods and it flies great. My questions are: 1. Is this a good c.g. for the first flight. 2. How much elevator throw should I dial in. 3. Would you recommend any differential. 4. Does it fly much different than the predator bat, and if so, how. Any other advice would be appreciated.
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Old Mar 31, 2007, 07:34 PM
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Minimum elevator throws as thes birds are very pitch sensitive , also the c.g measurment is at 4 3/8" from memory , it looks like a great addittion to the fleet , differential on ailerons would be useless , i just have full and half setting on my optic , the superfreak is awesome in all lft , enjoy it heaps..

cheers
doug
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Old Mar 31, 2007, 08:19 PM
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My dvd instructions for the super freak has the cg set at 6 1/2 inches so I would think 6 1/4 would work. I just maidened my predator bat at eagle butte today and learned what I should have already known. I went with the furthest back cg that Kyle uses, but he suggested I go a 1/4 in farther forward. Should have listened to him. I forgot to put the dual rates on my elevator and the first throw I slammed it to the ground. Second throw after adjustments it slammed to the ground again. Third throw it flew but with way too much elevator throw so it was all over the place and went into the ground again. I went to the car moved the cg forward 1/4 inch and this time remembered to turn the dual rates on and it finally flew. The end results was that before I went home it was flying on 50 percent throw on elevator (about 5/16 total)and the cg where Kyle had suggested I start with. Good luck with the Super Freak. ROB
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Old Mar 31, 2007, 09:27 PM
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Hey flybaby, Is that 4 3/8 c.g. a typo? I'm flying my predator bat at 5.
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Old Apr 01, 2007, 12:11 AM
The Predator
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And the 6 1/2" for the Freak.
Awsome looking ship you got there! The CG is at a great place to start just bring along something, like a nail, to slide into the tail flutes if you think you want to go back with the CG after the first test flight!

I like setting up both rates to cover everything, alierons: Low rate 25% high rates 40%, Elevator: Low rates 18% high rates 30% No differencial to start with. I must add the rate %'s can be VERY misleading if we are using different servo arm lengths, lever lengths so. . . Just make sure your low rates are pretty low, 1/8" up and 1/8" down on the elevons for elevator. Then use a nice spead for the higher rates, like almost double, and you can just flip a switch if you need to change FAST. If you have already built a nice flying Predator Bat you should be all set. Just handle it similarly, and like ANY plank, never get a cg behind the aerodynamic center or your in for one WILD ride. The Freak is a bit more wing and less plank and that'll be the difference in flight chracteristics.
I'll post a pic of my new Predator Bat, maidened it today, and after ONLY ONE flop into the cliff face (monster nasty shear to launch through too, alittle out of trim) I had it out rippen and DSing HARD! May have gotten a tad of video too!
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Old Apr 01, 2007, 01:47 AM
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Man, I guess the Pred Bats were out today. I finally got a chance to DS my Burly Bat in 15-24mph winds. My CG is 5-1/8. It tucks in a dive and ballons inverted but I'm thinking of moving it back even more due to it carring a lot of uptrim. I've got my ele rates at 25% and no exp which is unusual for me. I'm not so good at finding the groove but I think i got the bat cranking to about 70-80mph!!. Hopefully some vid tomorrow if conditions are good. I'm officially addicted to DS. Thanks again to Karl.
stu
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Old Apr 01, 2007, 10:55 AM
The Predator
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The CG does vary with Bats and Freaks! It is mainly contingent on how much reflex remains in the fixed elevons, positive or negative. With the stock reflex, a lot of reflex, the CG is around where Ming states it to be in his instructions for the stock build, WAY Forward! Less reflex takes the CG further back until you have NO REFLEX, then you MIGHT be able to hit 5 1/8" CG.
My lastest Predator Bat, the one I maidened yesterday, was at 5" and my mobile elevons were about 1mm higher then the fixed elevons for flat and level flight once trimmed. It flew flawlessly inverted and had VERY axial rolls, tough for a big plank with no fuse. I was Very happy with all flight characteristics but, I wish I had build it a few ozs heavier then the 30 OZS for pure speed. I think I'll add balast bays, 3/4" plumbing caps 1/4 span out at the CG so that I can slide in two 3/4" cylinders of lead to add 6 OZS and some span loading!
100 MPH, Bail on moving the CG back! The added reflex is the only thing keeping your bat from feaking out! I'd actually go for nose weight and, MOST important, make sure your elevons have no negative "down" reflex (the "up" reflex in the mobile elevons is likely compensating for that) even give a tiny touch of "up" reflex in the fixed elevons by shrinking the covering more right on the top surface of the joint where the fixed elevons attach to the body while under light constant presure holding your new desired position. This should bring all the elevons, fixed and mobile right in line (verify EVERYTHING is in line using the mobile elevons as a "plane" the fixed elevons should line up with on both sides, INBOARD AND OUT). This adds efficiency and killls off any tuck tendencies. Do Small steps on this. I'd do the fixed elevons bend first, just a 1/16" up, something you can not do in the field, then play with the cg at your slope to dial it in perfect. Going behind a 5 1/8" cg will likely render your ship Tuck crazy! Tough to land soft let alone fly at all!!!!
After looking at the pics, theoretically, I would have PERFECT efficiency, minimal induced drag for stability during upright flight, if I was to raise my fixed elevons 1/2 the distance to the current trimmed position of my mobile elevons. The the new trimmed posion for flat and level flight would leave everything PERFECTLY alined since I would have to compensate with the new trim by lowering the mobile elevons a TINY TAD since I raised the fixed ones, then they should be meeting perfect each move half waytowards the other!
Personally, and for any pilot that flys inverted ALOT and does acro/ DS acro, I have it PERFECT as picture! The reason for this??? you may wonder, because when I'm trimmed for flat and level flight inverted my mobile elevons are EXACTLY the same distance BELOW the fixed elevons as they were above for upright flight. Simply put, I have symetrical but opposite flat and level trim positions, 1 mm of up reflex for upright flight and 1 mm of down for inverted flight. The fixed elevons obviouly do not move and remain in a perfectly neutral position ALL THE TIME! The only MORE efficient setup would be to go to full span elevons so EVERYTHING would be mobile AND alined, being all one big elevon per side. Been there done that and with such HUGE elevons, I had flutter issues at high speeds even using a control horn just short of centered on the elevons! So I guess I've maxed it all out. Suggestions welcome. If you truely understand what I'm explaining here you will have a VERY solid grasp of how to PERFECTLY trim a plank, just a bit of learning about the aero dynamic center and it's relation to CG and YOU TOO will be and EXPERT , well kinda! This is a great learning tool FOR SURE!
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Old Apr 01, 2007, 01:39 PM
Objects in mirror are losing
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Thanks Pred. Last night I did what you recommended and attempted to tweak a little reflex into the fixed TE. I also removed a little tail weight. The nose on my Bat my be a little pointier than some, that could explain the extra 1/8". My only disappointment now is the Monocote isn't holding up like I had hoped but I doubt anything will at this weight. Great pics btw. Is the vertical on your Bat 4mm?
stu
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Old Apr 01, 2007, 07:43 PM
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Quote:
Originally Posted by berkshire sloper
Hey flybaby, Is that 4 3/8 c.g. a typo? I'm flying my predator bat at 5.
yeah , ill have to check... ill get photos..

cheers
doug
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Old Dec 31, 2008, 08:47 PM
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My SuperFreak Bat is flying at 6 3/8 CG
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