Harry Wilson Posted July 7, 2012 Share Posted July 7, 2012 Hi, I bought an F9F foam model reviewed here: **LINK** but try as I might could not get the thing to fly! I have tried several positions for the battery pack which put the C of G forward or back from the stated position with the recommended control throws. I end up either too nose heavy with no control authority or too tail heavy with no control at all. Theory says somewhere in between lies the answer but each attempt results in repair work so... Could anyone who has been successful with this model tell me exactly what set up they used? I am beginning to think the design point as specified is simply wrong; could this be the case? Cheers, Harry Wilson Quote Link to comment Share on other sites More sharing options...
Edge Posted July 10, 2012 Share Posted July 10, 2012 Hi Harry I bought one at the Weston Park show, and it is a great little package. I have scoured the internet forums for advice (and there is a lot of it about!!) I copied some of the more useful snippets and have put this at the end of this message for you. Maidened it last week with a 2200mah 25c lipo shoved right up the front and it seemed to pull away ok, but the 30amp ESC cut out and I had to "land". Not much damage and - now with a 40amp ESC - it is ready to go again (just waiting on the weather....). If I find the ideal cg position I'll let you know. Cheers David I just checked the CG, with the stock pack in the above location the CG is 1-5/8" behind the inlets. It flew much more balanced with the 2100 packs though, that moved the CG to 1-3/8" behind the inlets. I got in another flight this evening, flew it back-to-back with the Sabre for comparison. Despite looking quite a bit different, they're very similar in flight characteristics. Now that I've had a chance to compare them closely, they do seem to be about the same speed. Aerobatics are almost identical between the two. The Panther has some odd stall characteristics now and then, probably because it's still a little tail heavy. Out of curiosity I pulled the ESC off the velcro and shoved it back so that it was in the cavity between the inlets. Sure enough, it did not shut down this time even though I flew on the 2100 packs and at WOT much of the flight (to test the ESC). It appears that if enough cooling air gets on the ESC then it can handle the load OK. I'm flying with the ailerons on the recommended high rate (with some expo) and the elevator on the recommended low rate. The elevator is pretty sensitive even with the CG set ahead of the recommended spot, but when I was flying on the recommended CG the elevator was REALLY sensitive and would induce stalls quickly if too much input was given. Five flights with various lipos today, starting out with three flights with 25C 1800mah packs, and one flight each on a 2000, and a 2200mah pack. I noticed that it flew a bit tail heavy using the 1600mah stock pack, so I thought the 1800's might bring the COG forward, but I realized that the instruction manual shows the COG with the optional landing gear installed, hence the tail heavy attitude using the 1600. It still flew a bit tail heavy with the 1800's, so I tried the larger 2000 & 2200mah packs next and finally got it to balance at the recommended COG with the 2200mah. The larger packs won't go all the way up into the nose due to their size, but there is plenty of room on the battery tray for them so I gave it a go; I think I found the sweet spot! Though the Panther will fly well in a tail-heavy condition, it really flies like a dream using the heavier 2200 packs. Slow speed handling improved, and rolls were actually rolls, not twisting wallowing spins like when using the stock 1600 pack. Well, according to Jason at Hobby Lobby the 30A esc should be fine, but most folks on the RCG thread changed theirs out right away, (I only got one flight out of the stock esc before it failed; thankfully not while in flight). I think the Tbird 36 will be just fine, I did some bench tests and at WOT got a momentary burst to 32A, then it settled down to 28-29A, so the 36 should be fine. Though a few folks are still using the stock esc, I wouldn't want to risk an in-flight failure. HL is sending me a replacement stock esc, no questions asked, (that tells me they are aware of the problems with the stock unit), but I won't use it in the Panther. Pay attention to the supplied control rods, I ended up enitirely replacing them and the clevis' in mine. Also, the instructions show the COG at 1 3/4" back from the leading edge, but if you're not using the optional landing gear with the servo up front, it will take a 2200mah pack to get it to balance properly. My first couple of flights I used the stock 1600 & an 1800mah pack because they fit up into the nose, but the plane was obviously tail-heavy, (flew good that way, but definitely tail-heavy). There is plenty of room for a 2200mah on the tray, so use one of that size if you have one. had a chance to take the vh version out of the box. canopy was a bit warped, contacted vh, they are sending me another canopy. i noticed in the manual, they have put tape over the cg #'s, and changed the 1 3/4" 45mm to 1 3/8" 36mm. everything else is exactally the same. this is a father's day gift, so can not do anything until Sunday. sounds like a nice midnight project.... Quote Link to comment Share on other sites More sharing options...
Harry Wilson Posted July 13, 2012 Author Share Posted July 13, 2012 Hello David, Thanks for this. I really appreciate the input and your efforts. So based on all of this I'm going to try to set mine up at the 1 3/8 (36mm) position and will keep you posted. I'll also check which ESC was fitted though on the bench at least I am having no problems. Clearly I need a longer flight to be sure things are ok in the air. I will also dial in some expo on the ailerons but do you have any comments on differential this does not seem to get a mention - at the moment I think I'm using 10%. Cheers and thanks again, Harry Edited By Harry Wilson on 13/07/2012 07:17:33 Quote Link to comment Share on other sites More sharing options...
Edge Posted July 13, 2012 Share Posted July 13, 2012 Hi Harry Others did the work, I just gleaned from the Forums! I do not generally bother with differential, but when I get to fly it I may investigate. A good dose of exponential is a good idea though, as during the brief flight I had, it was sensitive on aileron. Anyway, the stock 30 amp ESC will probably be ok with the 1800 mah lipo provided but will not like a 2200 mah lipo. I robbed my EFlite Sea Fury of a 40amp Hobbywing ESC and I have hot-glued it to the top of the ducting as shown in the first photo below. The plastic plate with the cheater holes cut in comes off easily with a little care to facilitate this, although beware of the paint coming off as it is painted on the inside; easily touched up though. Other mods. are : cut a cooling hole in the noseleg blanking plate to get some air over the lipo carbon rod let into spanwise panel line on underside of wing, as there is a weak point where the servo cut-out is. The model survived a couple of cartwheels with this addition, so it seems to work! Have also received two ultra-slim 2200 mah 25c lipos from Hobbyking that fit into the battery area and can be moved around to find that elusive cg, plus a smart pilot and wing skids to protect the aileron linkages when landing on grass - again, photo below. Have also brushed on a couple of coats of Skin-Crylic from Falcon Aviation to help protect the exterior - it also removes that odd tacky feel of the original paint and protects the decals. I really want to fly it now, as the longer I cannot, the more fiddling I shall do! Cheers David Edited By Edge on 13/07/2012 13:43:03 Edited By Edge on 13/07/2012 13:43:59 Quote Link to comment Share on other sites More sharing options...
Edge Posted July 27, 2012 Share Posted July 27, 2012 Harry The Panther flew yesterday evening, and very good it was too! Pulled away well from a hand launch (by my friend Jon) and grooved around very well. Slowed up nicely for landing and was good fun all round. CG was at 344/345 mm from the front of the intake, balanced inverted - this photo is of the top of the starboard wing : The Lipo I used was a 3S Zippy 2200mah 20C that weighs 165g. This seems to work well and was barely warm after the flight. Perhaps my cooling mod worked, and it was helped by not having it at WOT all the time. The replacement 40 amp ESC is a definite good idea for a larger lipo. This photo shows the lipo position : Another friend is about to get his in the air, so we shall report further - good luck with yours. Cheers David Quote Link to comment Share on other sites More sharing options...
Dizz Posted July 27, 2012 Share Posted July 27, 2012 Nice one, always a big confidence boost when the first flight goes well. Pete Quote Link to comment Share on other sites More sharing options...
Edge Posted July 27, 2012 Share Posted July 27, 2012 Oh yes........ Quote Link to comment Share on other sites More sharing options...
Harry Wilson Posted August 4, 2012 Author Share Posted August 4, 2012 Hi, This is really good to know. Looks like a nice flying site too. Soon as I can get mine back in the air I'll report how I get on but I feel more confident now based on your findings. Harry Quote Link to comment Share on other sites More sharing options...
Edge Posted August 4, 2012 Share Posted August 4, 2012 Good luck Harry. I like the Panther so much I have bought the Mig 15 !! Quote Link to comment Share on other sites More sharing options...
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