chris larkins Posted April 19, 2015 Share Posted April 19, 2015 I have long thought about getting the Hobbyking Cri-Cri (1778mm version), it was recently in the Easter sale from the European warehouse so I duly ordered one (total cost £146 inc p&p). I have decided to document the process of putting one together along with all the ups and downs along the way. There has been a build log over on RcGroups so I will be taking on board a few of the suggestions from others. Here is the link to the model. **LINK** Edited By chris larkins on 19/04/2015 19:30:12 Edited By chris larkins on 19/04/2015 19:30:50 Quote Link to comment Share on other sites More sharing options...
chris larkins Posted April 19, 2015 Author Share Posted April 19, 2015 This is the full size plane that the model is based on, the span is just 4.9m which makes the model just a shade bigger than 1/3 scale. Quote Link to comment Share on other sites More sharing options...
Bill_B Posted April 19, 2015 Share Posted April 19, 2015 I love the Cri Cri due to its quirkiness, it's sort of ugly beautiful, but I think a decent 1/3 scale pilot will cost more than the plane! Looking forward to your progress. Quote Link to comment Share on other sites More sharing options...
chris larkins Posted April 19, 2015 Author Share Posted April 19, 2015 Thanks Bill, any comments along the way are welcome. The model arrived in the post yesterday so I have spent the afternoon deciding which equipment I will be fitting. The pics below are of the box, everything was securely packaged and so far it seems that the model is in good condition with no damage. Quote Link to comment Share on other sites More sharing options...
Dave Hopkin Posted April 19, 2015 Share Posted April 19, 2015 Yeah i have looked at this one on HK several times, always been on the verge of buying it but never had, I shall be watching this one with interest Quote Link to comment Share on other sites More sharing options...
Brian Pearson Posted April 19, 2015 Share Posted April 19, 2015 Hi. Just finished mine. Always wanted a full size. ...nearly bought one years ago. To me it's a thing of beauty.Should maiden it this week. I'll put some pics up if I can work out how to. Quote Link to comment Share on other sites More sharing options...
chris larkins Posted April 19, 2015 Author Share Posted April 19, 2015 So after what seems like hours of research and internet searching I have finally decided what gear to equip the Cri-Cri with, orders have been placed so it will be the waiting game now. Servos - to start off with there is an error in the instructions, it states 4 servos are required but it is actually 5 if you fit a (suggested) nose steering servo. The holes for the servos are pre-cut in both the wings and in the fin for the elevator servo. These holes are 23mmx12mm or 33mmx12mm including the mounting lugs, this pretty much limits you to fitting servos in the 12 gram range. I would have liked to have fitted at least 17g servos but this would require a little surgery. The holes for the rudder and steering servo are the same size but these could be easily enlarged as they just fit through the hole and screw directly to the plate rather than having a pre-cut step for the mounting lugs, I am going to fit a separate steering servo so I have decided to stick with the 12g servos. I have ordered some Corona DS-939MG servos as I have used these in the past with good results and they fit perfectly (plus I had one left over from another project), the specs are Weight: 12.5g, Torque: 2.5kg.cm, Speed: 0.14 sec/60, price: £4.96. **LINK** Motors - I have used Emax BL series motors on other projects and have found them to be great value, I will be running on 4s with 11x5.5 props so based on this I have selected the Emax BL2820/07. This should give me more than enough power and enable me to throttle back once airborne to give me decent flight times. These were ordered from model accessories and were £16.56 each. **LINK** ESC - I have gone with 70a (Opto) Red Brick ESC's as I wanted something simple without too many programming options, this should give me plenty of headroom as the amp draw should be way below 70a. I will be using a separate UBEC so have gone with ESC's that don't have a built in BEC. £12.68 each **LINK** UBEC - I have ordered a Dr Mad thrust UBEC, despite being labelled as a UBEC it is actually an SBEC. This have a 3A supply to the receiver and has an inbuilt Aux controlled on/off switch which has a 2A 5/6v output, I will use this to turn a landing light on/off using a spare receiver channel. £5.92 **LINK** Battery - I have ordered a Zippy 4s 5000mAh 30C Li-po, £24.51 **LINK** Quote Link to comment Share on other sites More sharing options...
Bill_B Posted April 20, 2015 Share Posted April 20, 2015 Chris, I think you're hardware choice is good for the model in question. I've had bomb proof service from Red Brick ESCs and use Zippy batteries in nearly all my leccy stuff. They seem far more resilient than the seemingly over hyped Nano Techs, in my experience anyway. I'm also using some of the Corona servos, albeit dedicated slim wing servos in gliders, but so far they're providing good service. There seems to be a bit of mixed opinion on these if you trawl the web, but like anything mass produced there'll always be the odd one that's duff. Not sure about the motors as I've not used this particular make. Quote Link to comment Share on other sites More sharing options...
Dave Hopkin Posted April 20, 2015 Share Posted April 20, 2015 Is it me or my maths Wieght from box lid 3000g roughly 6lb Two x 991W motors = roughly 2000W Which makes for 330W per lb Seems a bit OTT its early so I may be typing utter rubbish of course Edited By Dave Hopkin on 20/04/2015 07:48:01 Quote Link to comment Share on other sites More sharing options...
Bill_B Posted April 20, 2015 Share Posted April 20, 2015 It seems like you could run these motors on 3s and still have sufficient power. Have a look-see on HERE at the specifications. Quote Link to comment Share on other sites More sharing options...
chris larkins Posted April 20, 2015 Author Share Posted April 20, 2015 Hi Dave, your maths are correct but the spec's on these Emax motors are a bit optimistic. In my experience and with a 5.5 pitch prop I have only achieved around two thirds of the watts that are quoted on the box. As soon as the motors and battery are delivered I will hook them up to my watt meter to see 'watts wot', I am expecting to see about 600 watts per side, which would work out at approx 200W per lb. Quote Link to comment Share on other sites More sharing options...
ron evans Posted April 20, 2015 Share Posted April 20, 2015 Hi Chris, I run one of these motors in a 3.5lb 65" aerobat. On 3s an 11x5.5 draws 22A and it will not quite hold a hover. On a 12x6 it draws 29A and it will climb vertically. Examples will vary of course, and you will probably need a bit more speed, so perhaps an 11x7 would be more appropriate. Ron Quote Link to comment Share on other sites More sharing options...
ron evans Posted April 20, 2015 Share Posted April 20, 2015 Hi Chris, just re read your post and see you are going to use a 4s, so my ramble would not be much use. Sorry Ron. Quote Link to comment Share on other sites More sharing options...
Brian Pearson Posted April 20, 2015 Share Posted April 20, 2015 Mine gives 1480 watts on 9 by 6 4cell. I only went 9" as it was closest to scale.Edited By Brian Pearson on 20/04/2015 16:14:55Edited By Brian Pearson on 20/04/2015 16:36:51Edited By Brian Pearson on 20/04/2015 16:37:21 Quote Link to comment Share on other sites More sharing options...
jolliffee Posted April 20, 2015 Share Posted April 20, 2015 HI Chris. I have purchased one of these but not started to build it yet but I have purchased two Turnigy Aerodrive SK3 - 3536-1200kv motors. I will be keen to see how you proceed with your build so please keep up the god work! David Quote Link to comment Share on other sites More sharing options...
jolliffee Posted April 20, 2015 Share Posted April 20, 2015 Posted by Brian Pearson on 19/04/2015 20:01:27: Hi. Just finished mine. Always wanted a full size. ...nearly bought one years ago. To me it's a thing of beauty. Should maiden it this week. I'll put some pics up if I can work out how to. I was wondering what motors and ESC's you used? David Quote Link to comment Share on other sites More sharing options...
Brian Pearson Posted April 20, 2015 Share Posted April 20, 2015 Hi David. I'll have to dig out the numbers but the motors were turning gold type slightly deeper than the aerodrome ones.think I used 40 or 50 amp basic esc's and a separate lipo for the radio.looking at report it llooks like 3 cell is plenty but I've got a 4 cell battery. Quote Link to comment Share on other sites More sharing options...
Brian Pearson Posted April 20, 2015 Share Posted April 20, 2015 I had to grind the shaft off and fit bolt on prop adaptors. This gave perfect fit for the spinner. So smaller motors would probably be better. Quote Link to comment Share on other sites More sharing options...
chris larkins Posted April 20, 2015 Author Share Posted April 20, 2015 Whilst waiting for the bits to arrive I got on with hinging the ailerons, these are supplied with furry cyano type hinges (3 per aileron). It's probably overkill but force of habit made me pin these hinges with cocktail sticks, I will cover these with an off-cut of profilm later. I have also removed the film covering the hole for the servo in both of the wings and for the elevator servo in the fin, this shows the cut-out which limits you to a servo of 33mm in length (including the lugs) unless you want to perform some minor surgery. Quote Link to comment Share on other sites More sharing options...
Chris Jones 7 Posted April 20, 2015 Share Posted April 20, 2015 Following this with interest. I think one of these is going to be my winter project with a scale cockpit, animated pilot and FPV system in his head. Interested to see what you make of it. Edited By Chris Jones 7 on 20/04/2015 23:14:38 Quote Link to comment Share on other sites More sharing options...
Peter Miller Posted April 21, 2015 Share Posted April 21, 2015 Nearly 20 years ago I went to the PFA rally at Cranfield. The originnal Cri Cri was being demonstrated there. IT was flown through every aerobatic you can think of but my abiding memory was of the Cri Cri flying down the runway at about 10 to 15 feet height...INVERTED The sound of that aircraft with its two little two strokes on tuned pipes was enough to curl your toes Quote Link to comment Share on other sites More sharing options...
chris larkins Posted April 21, 2015 Author Share Posted April 21, 2015 I agree Peter, the fullsize makes quite an impression when you see it in action. I too first saw the cri-cri at Cranfield many years ago. My daughter witnessed one at an airshow last summer and she thought it was hilarious. Most of the bits have arrived although I am still waiting for the speed controllers, I ordered four 11x5.5 props from Hobbyking with two of then clockwise rotation so I can set the model up with contra-rotating props. The batteries look fine although the leads are huge (8 AWG), I haven't stripped the heatshrink off yet but I very much doubt the wire will fit into an XT60 plug which I normally use. Quote Link to comment Share on other sites More sharing options...
Peter Miller Posted April 22, 2015 Share Posted April 22, 2015 If I remember corrrectly the full size only uses 24" propellers. I also remember that a Frenchman built a 1:1 R/C version. His pilot was an inflatable one!!! I will go no further Quote Link to comment Share on other sites More sharing options...
Bill_B Posted April 22, 2015 Share Posted April 22, 2015 Posted by Peter Miller on 22/04/2015 08:19:08: I also remember that a Frenchman built a 1:1 R/C version. His pilot was an inflatable one!!! I will go no further Ooh, now I'm interested! I haven't got a Cri Cri, but where do we get these inflatable pilots from? Quote Link to comment Share on other sites More sharing options...
Peter Miller Posted April 22, 2015 Share Posted April 22, 2015 Ask the moderators to explain!! Quote Link to comment Share on other sites More sharing options...
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