Chris Chaplin Posted February 16, 2009 Share Posted February 16, 2009 Hi All builders I`ve Just picked up a A26 Invader, plans & kit by wing mfg short kit. Has any one build one of these, I`m looking to convert it from 2x I.C.0.25 up to .45 rated IC. to the Electric brushless ones. Any suggestion on motors & battery (lipo) set up. Spec... made from balsa & liteply wing span 68" Length 54" Wing area 748 sq inch weight around 7.5 Ibs up to 10 lbs ( will build lighter were possable). twin engined ic rating 0.25cc up to 0.45cc flight speed 70-80mph flaps landing est 20 mph? Scale is 1-1/4" = 1" 4-6 ch model Look forward to hearing from you all. Cheers Chris C. Quote Link to comment Share on other sites More sharing options...
Tim Mackey Posted February 16, 2009 Share Posted February 16, 2009 25 - 40 size IC means you will need around 500 - 1000 watts for each motor. For fairly fast pitch speed, you will need highish Kv motors - so expect a thirsty setup. Something like this maybe..... On the middle range of 750watts per motor, that implies at least 4s Lipo and probably better 5s, or the current draw will simply be too high to be reasonable. Heres another possibility and cracking VFM @ 57 quid considering it includes the ESc Have you considered using M1s? If you stick with lipos, then 750 watts from a 5s lipo will pull about 40A + so aim for 50 -60 Amp ESCs ( you will need one for each motor ) and batteries of at least 3000mAhr capacity for reasonable flight times. Quote Link to comment Share on other sites More sharing options...
Chris Chaplin Posted February 17, 2009 Author Share Posted February 17, 2009 Thanks Timbo, I was looking at around 850watts per engine. your suggections are great, makes it alot cheaper for setup than expected. I`ld be going for the lightest flight setup around 7.5 lbs. Batterys do not have to be lipo`s, other nicad suggetions welcome. just playing around with power set ups now, in planning stage, so save time and money Will post a few photo of basic kit later, so you can see the scale of this project. Cheers Chris. Quote Link to comment Share on other sites More sharing options...
Tim Mackey Posted February 17, 2009 Share Posted February 17, 2009 I wasnt suggesting Nicds - the other alternatives are M1 cells from A123 technology. Do you get the mag? - I have had a pretty thorough 2 part article running on all sorts of batteries in the last two issues - may be worth you getting them. You COULD use Nicd - although these days more likely to be NiMHs, - Puffin models do a really nice 4A cell, but the amount needed for the voltage required will come out quite heavy. Quote Link to comment Share on other sites More sharing options...
Chris Chaplin Posted February 17, 2009 Author Share Posted February 17, 2009 Yes I`ve have the mag. thanks. Just looking at options. will proberly go with lipo`s option setup. Here is a few pics... see what a great model it could be. And box lid info .... Looks cool. anyone got any good paint themes? If i lighten the build. being an ic kit, which areas could i lighten in build with ply & balsa. or does the eletric model same size need same frame stability. need to safe as safty first & it`s a large model. Cheers Chris C. Quote Link to comment Share on other sites More sharing options...
Fats Flyer Posted February 18, 2009 Share Posted February 18, 2009 Chris, I.C models are obviously designed and built to be alot more sturdier than electric models. For starters ,the engine bulkhead parts could possibly be changed for thinner and lighter wood,but not knowing the kit ,i dont know whats in the box.If there is a lot of ply formers ,these could be replaced by liteply and lightening holes on parts will reduce weight. i think lipo's will be the way to go as nihm's and nicads will be alot heavier and flight time will be reduced. But, all in all ,that seems to be a nice looking kit,that should keep you busy for a while. Please let use all know how you get on as you build and if there are any questions as you go through the build , Hey.....were all here to help. vince Quote Link to comment Share on other sites More sharing options...
Chris Chaplin Posted February 18, 2009 Author Share Posted February 18, 2009 Cheers Vince, The kit only has, 2 set of full size plans, various plastic moulds, 2x engine covers etc. 2x ply firewalls & 2x pre cut white foam cores for wings. there is no wood or balsa includes in short kit see photo. there is a bill of materials for the list of balsa, ply needed etc. So a clean sheet as to what grades of lite ply & balsa need. Should be fun, It is a long trem project I think, would love to get this one flying. Though i`m not able to fly this one yet, got to pass my A first then a year exp. flying. so ive got this year to build and hopefully ready to fly for next season. currently fliging my GWST6 & Innovator trainer. Cheers Chris. Quote Link to comment Share on other sites More sharing options...
Fats Flyer Posted February 19, 2009 Share Posted February 19, 2009 Sorry Chris, Didn't have my glasses on at the time.We'll that's even better then, you can resize the wood on the plane before you start. Nice to see your taking your time with learning to fly first ,how's the flying going, when do you hope to pass your A cert?. vince Quote Link to comment Share on other sites More sharing options...
Chris Chaplin Posted February 20, 2009 Author Share Posted February 20, 2009 Hope hope to pass my "A" in the next four to six months. Just waiting for the club trainer to maiden my planes & the weather so i can start trainning. I`ve been on the flight sim for nearly a year now (Aerofly deluxe) as well as flying my ex ic 30 Raptor & electric eskey belt cp heli`s. Sold my 2nd hand ic raptor last year after 2 unlucky chashes. The cash brought me 2 new electric planes & watt meter (T6 & Innovator). Found the cost of repairing the raptor too much, with 6 six kids etc. I love building planes, foamies or balsa scatch build from plans & very cheap to fix. I have almost ready double delta (balsa) free plan rc model world augt ed 2008. I picked up the A26 short kit for a "tenner" club bring and buy, looks a great model to build. you can`t beat a big target goal, fly it next year?. if not me then to see it fly what i built would be fantastic. Cheers Chris. Will keep this project updated as I built. Quote Link to comment Share on other sites More sharing options...
Chris Chaplin Posted February 26, 2009 Author Share Posted February 26, 2009 Thanks guys for your coments. So if I have this A26 Airframe and run 2x 750w motors & 2x Esc, (one motor per side). Is it best to run two batteries, one for each engine / motor. or would it be best to run both motors off one battery. Cheers Chris Quote Link to comment Share on other sites More sharing options...
Ben Mullins Posted February 26, 2009 Share Posted February 26, 2009 Your choice really, I would go for two 3s lipos and a reciever pack. I would have thought for any decent flight time you would need a rather large Lipo if you were going to go the singular route. Quote Link to comment Share on other sites More sharing options...
Tim Mackey Posted February 26, 2009 Share Posted February 26, 2009 I would use the two batteries in parallel as one large pack. This way they will empty at the same rate, and you will have one less thing to worry about as far as one motor dying before the other. Quote Link to comment Share on other sites More sharing options...
Chris Chaplin Posted February 27, 2009 Author Share Posted February 27, 2009 Cheers again, two batteries in parallel looks like the way to go, that would solve the engine failure worry. With the two esc`s in this set up, you have to disable the bec system on one of the esc, that is right? or with a model of this size, is it best to disable both and run thr rx on it`s own battery system. Quote Link to comment Share on other sites More sharing options...
Tim Mackey Posted February 27, 2009 Share Posted February 27, 2009 Motor my friend, motor Hmm, the old do I use a seperate battery debate I have my own personal opinions and reasoning on this one, and if I can find the correct thread after all this time and changes, I will link you to it. However, IF you decide to use the ESC BEC, then yes, many ESC BECS will fight with each other if paired up, so use just the one. Quote Link to comment Share on other sites More sharing options...
Tim Mackey Posted February 27, 2009 Share Posted February 27, 2009 Sorry cant find the thread now... but heres my text that I used in that and other threads. I stress again - my personal opinion and experience only! " BECS are actually safer than a separate battery" Let me explain why I think this could be so..... BECs ( whether separate or part of the ESC ) rely on getting their power from the main flight battery - a relatively meaty great big powerful beast. The ESC also features a low voltage cutoff circuit ( LVC ) designed to give visual but safe indication that the battery is running low. However even if the battery approaches this low level, it will still have more than enough juice left to continue powering the BEC / UBEC which in turn powers the receiver and brown out should therefore not happen ( assuming the BEC circuitry is "up to the job" ). A seperate Nixx battery pack on the other hand has the following potential problems. 1) It needs to be capable of supplying the correct voltage and current necessary - and many are not, especially smaller cell AA type. 2) It needs charging ( and by different means to that of the flight pack ) and this could be / has been forgotten. 3) Nickel based cells have a bad reputation for black wire disease - which most decent evidence seems to point to the chemistry of the electrolyte used. No such BWD has been found in Lithium cell based packs. 4) Perhaps most critically of all - if, for whatever reason, the separate pack runs low, or stops altogether due to a bad connection etc there will be no prior warning via the motor stopping / slowing / pulsing or whatever the ESC would normally do. The first signs of trouble will be the receiver stopping working altogether - including the flight controls! This will not be a "failsafe" situation - this only occurs with RF signal loss / interference This of course is dependant on the BEC / UBEC being reliable and capable enough for the job...which frankly these days the majority of them are. A separate circuit UBEC should run cooler ( provided it is within capability and has airflow around it ) than one built onto an already warm, hard working ESC PCB So in order of preference I will go for - in true miss world fashion EG: in reverse 6th place- the seperate 4 cell NiXX battery 5th place- the seperate 5 cell NiXX battery 4th place - the ESC BEC combo unit 3rd place - the UBEC powered by Nixx battery 2nd place - the UBEC powered by seperate LiPo Ist place - the UBEC powered by main flight pack Quick...call me a cab !! Quote Link to comment Share on other sites More sharing options...
Chris Chaplin Posted February 27, 2009 Author Share Posted February 27, 2009 cool, Thanks for the input, that helps me loads, thanks Timbo Quote Link to comment Share on other sites More sharing options...
Chris Chaplin Posted March 7, 2009 Author Share Posted March 7, 2009 Thanks for the input, guys just get the wood lite ply ordered and balsa then the cutting begins Will keep you posted as I build. Cheers Chris. Quote Link to comment Share on other sites More sharing options...
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