Chris Walby Posted October 9, 2022 Share Posted October 9, 2022 One of our mature club members is focusing on electric and is having a clear out so I thought these two were interesting. No idea who the designer or any info on what the c of g/throws are, but can sort that later. I would assume the Panther was a kit as a couple of parts are molded plastic with a OS LA46 upfront. The Mirage is running a 10 x 8 on a OS FX max 46. Panther is 47 1/2 wingspan and the Mirage is 34 3/4 wingspan. The plan will be to remove both engines and see if I can un-goo the OS in the Panther and replace the Mirage with electric. Add steerable nose wheels and servos where they are missing, jolly good check over and replace fuel lines. Can't say I like the Panther elevator linkage to elevator as it seems to have a fair bit of play + they are quite narrow. The Mirage will be interesting as it has a tail skid to prevent prop strike, so easing it off the deck might prove a little exciting. Questions for anyone knowing the answers Panther, kit manufacturer and if any drawings are available? Assuming both engines run ok which one would be best for this model? FX or LA Marage, kit manufacturer and if any drawings are available? Quote Link to comment Share on other sites More sharing options...
Guest Posted October 9, 2022 Share Posted October 9, 2022 Chris The Panther looks like one of Cambria/Cambrian models from their, --- Fighter's of the 50s series. I built this Purple Panther way back in 2005 with irvine 40 up front,it was deffo a bit hairy to fly,my fault due to incorrect C/G. Jim Quote Link to comment Share on other sites More sharing options...
Chris Walby Posted October 9, 2022 Author Share Posted October 9, 2022 47 minutes ago, Jim Carss said: Chris The Panther looks like one of Cambria/Cambrian models from their, --- Fighter's of the 50s series. I built this Purple Panther way back in 2005 with irvine 40 up front,it was deffo a bit hairy to fly,my fault due to incorrect C/G. Jim Cheers Jim, any idea where the C of g should be + did yours have a steerable nose wheel? Quote Link to comment Share on other sites More sharing options...
Martin Harris - Moderator Posted October 9, 2022 Share Posted October 9, 2022 (edited) Definitely the Cambrian. I flew that model a few years ago and I also have one tucked away in the loft. Mine was very heavily built - a gift from a different member which would flick with the merest provocation if flown at anything other than full throttle. Landing it was an interesting excercise… This one was a lot better but needs treating with respect. You may still be able to get info (and maybe the tip tanks as they’re listed on the website) from Cambrian if they don’t turn up: https://www.cambrianplanes.co.uk/ourshop/cat_266684-Fighters-of-the-Fifties-Series-Range.html Don’t get too confused to references to it as an F4F on parts of the website! I can’t help with the Mirage but I don’t have any strong memories of the test flight and it’s still in one piece so it must have flown OK. Does the previous owner not remember any details? P.S. You’re right about getting the Mirage off the ground - maybe a smaller diameter 3 blader might help. Look for any marks from - or remnants of - masking tape under the wings as the previous owner often marked the C of G that way. Edited October 9, 2022 by Martin Harris - Moderator Quote Link to comment Share on other sites More sharing options...
Chris Walby Posted October 10, 2022 Author Share Posted October 10, 2022 Hi, I'll message Cambrian and see if they will divulge the C of G/throws + any spares. Really don't like the elevator linkage arrangement so that will have to change and a bit of head scratching to make the nose wheel steerable. Other than test the engine...and a wheel, it should not be too much work. LA46 or FX 46 best for this? is there much power difference? As for the Mirage its proving tricky to find one that size in places like Outerzone, but there is enough information to extrapolate where the C of G should be (33%). This will more work, but should be worth the effort. If I pick a high KV motor a two blade same size and as mentioned, it has a skid to prevent prop strike....might limit rotation. Quote Link to comment Share on other sites More sharing options...
maurice northcott Posted October 10, 2022 Share Posted October 10, 2022 Chris, Mirage could possibly be the Billkits one, linky...... https://www.billkits.com/mirage-iiii/ Quote Link to comment Share on other sites More sharing options...
Chris Walby Posted October 10, 2022 Author Share Posted October 10, 2022 Nice one there Maurice, looks like the one. I'll contact Bill and see what info he has....might just order something else while I am at it. 🙂 1 Quote Link to comment Share on other sites More sharing options...
Guest Posted October 10, 2022 Share Posted October 10, 2022 Chris No nose wheel steering and can't remember C/G position,as Martin says it would flick if you blinked. Mine didn't last long due to the dreaded tip stall on downwind turn. I would go for a forward C/G to be on the safe side maybe 20/25 % of the wing chord.. Jim Quote Link to comment Share on other sites More sharing options...
Chris Walby Posted October 14, 2022 Author Share Posted October 14, 2022 Good news, Bill replied in less than 24 hours and Cambrian a little after that with all the information requested, bug thanks to them. Engine testing this weekend to see which engine runs the best...or just runs. Failing that I have a spare LA46 somewhere. Panther still needs work on the elevator linkage and the nose wheel steering sorting. Progress on the Mirage had a pleasant twist today as the engine weighs 472g and the electric 185g so being a pusher had 443g lead in the nose. The motor in stock is only 4S but its good for 70A so I'll test rig it with props and see what I can squeeze out of various 10 inch props! I have some 4S5000 lipos and if they are located up the pointy end I may not need any lead at all so double win. Quote Link to comment Share on other sites More sharing options...
john stones 1 - Moderator Posted October 14, 2022 Share Posted October 14, 2022 46 fx is by far the better engine. Quote Link to comment Share on other sites More sharing options...
Chris Walby Posted October 16, 2022 Author Share Posted October 16, 2022 Engine testing made the decision easier, the FX started and run up a treat with the minimal amount of tuning. The LA was completely different, tried everything and then noticed the odd counter sunk screw in the plastic backplate and a bit of play in the front bearing. It has a bit of compression but will only tick over a couple of seconds and then stop irrespective of throttle position. In the dark nights of winter I might pick it to bits and see what's going on. The other odd thing was air in the carb feed line as it would pull fuel through and then air would appear. I changed the needle to carb line, but suspect there might be a hole in the needle body. Better news on the Mirage front. The prop testing with the 4S4000 lipo, 80A ESC, motor and 11 x 7 produced 966W at 68A (close enough for a 70A rated motor!). The news got even better once the motor was fitted and the C of G checked. Quite surprised the battery needed to go that far back and a bonus it didn't need the pound of lead stuffed in the nose!. Just need to work up a battery tray, fit the ESC and extra long motor leads and set the RX up. And a bit of cooling for the ESC Last good news was that Bill of Billkits suggested AUW should be between 5 and 6 1/2 lbs and this now comes spot on the 5 lbs mark. Quote Link to comment Share on other sites More sharing options...
Paul De Tourtoulon Posted October 17, 2022 Share Posted October 17, 2022 My Mirage 2000 has a piped .61 in it, the servos, rx ,battery pack and around 150 grams of lead are at the rear end of the tail pipe. 1 Quote Link to comment Share on other sites More sharing options...
Engine Doctor Posted October 17, 2022 Share Posted October 17, 2022 13 hours ago, Chris Walby said: Engine testing made the decision easier, the FX started and run up a treat with the minimal amount of tuning. The LA was completely different, tried everything and then noticed the odd counter sunk screw in the plastic backplate and a bit of play in the front bearing. It has a bit of compression but will only tick over a couple of seconds and then stop irrespective of throttle position. In the dark nights of winter I might pick it to bits and see what's going on. The other odd thing was air in the carb feed line as it would pull fuel through and then air would appear. If the LA has low comp check if the chrome is coming off the cylinder lining. This is a death knell for an LA . Also if main bearing bush has play its knackered as both problems are an uneconomical repair . The main bearing play will not usually stop an ebgine from running but will cause it to have to have to be run rich to nake a seal . This also causes unburnt fuel to spitIf out from the front between the prop driver making it very thirsty and messy to run. If it's been run on castor and overheated then that will ruin an LA or any modern engine in short order. You might be lucky and find it's just a cracked and leaking backplate. Air leak in crankcase will prevent an engine from idling . The plastic backplate are not very forgiving especially if messed with by a heavy handed fiddler. Countersunk screws ring alarm bells ! Messed with an Irvine 53 at the field yesterday bought in a model by a club mate. It had obviously been run on castor as externally it looked like a chip pan! Bearings shot and piston felt sticky , probably burnt black with castor varnish so due a strip down and investigation. Quote Link to comment Share on other sites More sharing options...
Chris Walby Posted October 17, 2022 Author Share Posted October 17, 2022 Thanks Paul and ED for the info. Paul what's the AUW of yours? ED, I think it needs a total strip to see what's going on. Winter nights job, plus the general opinion is that the FX is a better engine and due to the weight/airframe I think it needs all the help it can get from the power plant. Quote Link to comment Share on other sites More sharing options...
Paul De Tourtoulon Posted October 17, 2022 Share Posted October 17, 2022 I will weigh it tomorrow,,, 1 Quote Link to comment Share on other sites More sharing options...
Paul De Tourtoulon Posted October 18, 2022 Share Posted October 18, 2022 Just spent 1/2h and 8 kilometres around the new one way system at Montpellier to do 1 kilometre, and all that for "0" bikes on the on the other side of the road !! Here you go Chris, Length 1m37 Span 1m05 Weight 4k400. Quote Link to comment Share on other sites More sharing options...
Chris Walby Posted October 18, 2022 Author Share Posted October 18, 2022 3 hours ago, Paul De Tourtoulon said: Just spent 1/2h and 8 kilometres around the new one way system at Montpellier to do 1 kilometre, and all that for "0" bikes on the on the other side of the road !! Here you go Chris, Length 1m37 Span 1m05 Weight 4k400. Sorry to hear about your forced diversion and thanks for the info. Wow at 39 1/2 wingspan and 9.7 lbs in old money is that the words fastest flying manhole cover! Top man that's all I can say. Took the Mirage up to the field today, checked it over, did range and failsafe checks plus a bit of taxi testing at walking speed. Clearly an issue with prop clearance as it bumped across the runway and prop striking. The collective decision would be to increase the main UC wheel diameter and possibly go for a 10 x 8 if the 11 x 7 keeps hitting the ground. Roll on Thursday for final check. Quote Link to comment Share on other sites More sharing options...
Paul De Tourtoulon Posted October 18, 2022 Share Posted October 18, 2022 It fly's faster than my Rafale with it's Wren's Jubilée,,,🥳 Quote Link to comment Share on other sites More sharing options...
Chris Walby Posted October 21, 2022 Author Share Posted October 21, 2022 Update time, bigger main wheels fitted, minor mod to the snake support agreed and the Mirage has passed the club inspection. Just needs favorable conditions and the bike clips for the maiden. Not so good news with the Panther. The OS FX 46 has the carb on the other side which clashes with the tank/servo installation, but sorted. The throttle servo did some odd things with the servo tester, like not travel the entire span it should, didn't like 6V but worked on 4.8, then worked on 6V. Not happy with that so the servo was replaced' I still don't like the elevator linkage arrangement so put this, the rudder and aileron servos on the servo tester (cycle mode) gave it 15 minutes. The elevator linkage soldered joint failed hence only one elevator was working. Now modified and working. Tried the C of G and found it 25mm too far forward so, so RX battery and RX are now mounted in the tail which seems to have resolved that issue without the addition of lead. I'll give it a weigh in and engine test tomorrow with luck, might even get a noise test. 1 Quote Link to comment Share on other sites More sharing options...
Paul De Tourtoulon Posted October 22, 2022 Share Posted October 22, 2022 What solder, it looks more like a lump of chewing gum .😮 Quote Link to comment Share on other sites More sharing options...
Chris Walby Posted October 23, 2022 Author Share Posted October 23, 2022 The Mirage was to say the least very lively. I looked very rearward C of G, ran out of down trim and had to hold 50% down stick just to maintain level flight! Didn't like slowing up so landed with a bit of a bump but no damage. Investigation to follow, remove reflex and reset trim. The Panther passed its noise test, rudder (split type needs a bit of work) and a major rethink on the C of G. Set in the workshop dry with slightly forward, but at the field with a full tank of fuel it was 25mm (1 inch) further forward...Going to fit a smaller tank further, C of G on the mark dry and then with fuel the C of G should only be 15mm max forward. Note to get current full tank C of G I have 150g on the tailplane, but what I didn't line was with an empty tank the C of G would have been behind the line. Investigations regarding the Mirage have found: The C of G was correctly set at 255mm back from wing plate An online delta calculator comes up with 293mm expert, 271mm allrounder and maiden/novice 250mm Another online calculator came up with between 250mm and 270mm Not sure because its at the light end of the weight range (5 to 6 1/2 lbs), smidge under 5 lbs or perhaps the thrust angle is out. IIRC its pitched up more without power and slowed! The other thing is the Elevons are set down (where I ran out of trim), so my thinking is currently the nose section produces lift or drag above the centreline or the wing is not sat on the fuselage correctly. As it rotated well on take off, I think I am going to try 240mm and see how it goes unless anyone has a better idea of what's going on! I might give Bill a call and see what his opinion is. Quote Link to comment Share on other sites More sharing options...
Chris Walby Posted November 20, 2022 Author Share Posted November 20, 2022 Update time! The brisk wind was a bit choppy today at height, but was straight down the longest runway so it was bike clips time. A helpful email from Bill of Billkits was in line with my thoughts around moving the C of G forward by 25mm and dial out down trim (I put a bit of reflex in and ran out of down trim on the maiden!). I had to remake the battery tray as the lipo needed to move about 100mm further forward to achieve the new C of G Although the grass is a bit long and the holes numerous the initial acceleration was brisk and rotation within 20 yards. Climb out was at a low angle and airspeed picked up a treat. Its pulling 68A on 4S so there is plenty of power for a 5lbs model. Did a few circuits with the conclusion that the aileron rate is too high and the elevator a bit too low although it didn't need much trimming. What it does seem to do is lift its nose when I roll which them results in a loss of airspeed. The resultant reduction in airspeed causes it to feel like its stalling and it then drop its nose/reduction of control authority. Once it picks airspeed up the control authority returns! Use of rudder seems to reduce this tendency so I will try that a bit more next time. 3 minutes of flight left me with 40%, but could be extended with throttle management or perhaps not! Landing was ok although as airspeed reduces so does the control authority, but this is way before it will nose up and land slowly so its just another little thing to remember! Looking good so far and I'll post a photo once downloaded from the phone 1 Quote Link to comment Share on other sites More sharing options...
Chris Walby Posted November 20, 2022 Author Share Posted November 20, 2022 A mix of all sorts today, Grumpy Tiger Cub twin, FT Versa with tractor & pusher motors (good in windy conditions) and the pusher Mirage. Quote Link to comment Share on other sites More sharing options...
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