Alex' Jitterbug from depron.

[Shane Sunday]

Well after hmmmming and haaaaing over which plan to build from all the issues I have so far I have decided on Alex Wittakers Jitterbug. Sure it's no F4U Corsair or F-18 Hornet EDF style. But it does tick a lot of boxes for me. First off as someone who has a build bug built in all year long I have found the ease to this project enticing. The fact that I have a load of depron kicking around certainly helps. Also the fact that it's not built to be a speed demon but as well still be quite aerobatic makes the Jitterbug very appealing. I have built a couple balsa models but prefer the simplicity of depron. The other thing that sold me on the Jitterbug was the fact that I have about 3 motors that could possibly go into it giving it differing performances. Besides I just needed something to build on those rainy days when I can't fly.

 

So... I started out by cutting all of my ribs by sandwiching 5 together at a time and using my scroll saw to cut them out. I would have likes to do more but the scroll saw won't accept it. The great thing about the sandwich technique and depron is that all Id to do was push some pins through my template and the depron and they came out perfectly. Well almost.

 

I then laid my spruce bearers on the plans, tapping the bottom one down and started to hot glue them in place along the plan. The spacers were cut out and glued to the spruce bearer and a depron T/E was added gluing this to the rib ends. I felt that the T/E was a bit flimsy so added a 4mm carbon rod about 2cm in front of the T/E by sharpening a suitably sized brass tube and gently spinning while cutting the holes. A couple of the ribs were out of alignment so I corected this by simply cutting the hole a little higher or lower as need then just glued the carbon rod into position.

 

The L/E was made up of 3 laminated 6mm pieces of depron cut to size, glued into place then sanded to shape.no real difficulties there. As there was no visible diagram for the dihedral on the plan I just borrowed one from another plan I had kickin around.

 

I decided I was going to sheet the wing using 2mm white depron. This is real light stuff but surprisingly strong. The question was How am I going to glue and cover in time as the hot glue will be too cold by the time I got to the other end of the wing? The answer came from another bloke on another forum... Double sided tape! 3M double sided tape used for tacking underlay. Fantastically strong stuff yet ultra thing. I just tapped the leading edge and all the ribs then lay the sheet on the workbench and rolled the wing on top of it. Doing it this way made sure the surface was flat and the tape just will not let go.

 

 

I'll just finnish off this wing and then start on the fuse. So stay tuned.

 

 

Edited By Shane Sunday on 06/05/2011 10:24:55

Edited By Shane Sunday on 06/05/2011 10:26:12

[Tim Mackey]

Watching with interest here Shane

[Tim Hooper]

Is this an electric version? Whatever will Uncle Alex say? Goodness me.......

I've not checked it myself, but I do hear that there may be a discrepancy between the wing chord and the wing seat on the fuselage. I could be wrong though.

Keep posting the pics anyway!

 

tim

[Shane Sunday]

Yes this will be an electric build. Go green! ahem. Sorry guys. I'm unsure about the wing seat and cord thingy but I'm sure I should. I'll look into that though. Thanks for the heads up.

 

Tonight was quite eventful. I managed to finish the second half of the wing and join them together. I hate joining wings. This is the 4th set I've done and it's always a bungle. I think I have it this time without having to tear it apart. I bet some of you were wondering exactly how was I going to join a depron wing of this size and hope to have structural integrity. In the end it came down to this. My dihedral wing joiner. 7 inches either side and epoxied in place. It has worked a treat. That and and awful lot of clamps will get the job done. Now I don't profess to be the smoothest builder out there so there is obviously a little filler work to be done here and there but over all I am happy. Once I had the wing joined I had to figure out how I was going to mount my servos as well as keep the weight down so glued in a 12mm (2 6mm laminated) Into position so that later I can cut into them and seat my servos.

 

Please don't look at the work space it's the wing we are looking at here. I have 2 questions about the wing. 1) Does anyone have the weight for their balsa built wing? 2) Is it suppose to be swept back like that? I've seen wings like this before but couldn't tell in the mag weather or not I have it wrong. I sure hope not. Well tomorrow I have a BBQ to attend which will mean no building. Booooooo. I so wanted to sheet the top and cap the ends.

Till Sunday I guess.

 

Cheers

 

[Shane Sunday]

Oh ok I just got out my Issue with the Jitterbug. My wing is wrong!!!!! Damn. There should not be any sweep in the wing. ******************. Why Oh why. Well I'll get to work on the fuse next. I'll sort something with the wing.

 

[Shane Sunday]

I checked into the wing seat and there is a simple fix to the problem. I had planned on skinning the wing cord with balsa anyhow to strengthen the seat and cord area. So it looks like I will have to cut a notch out to fit the seat on the fuse.

 

I apologize for earlier where I said there didn't seem to be a dihedral on the drawing. I need to open my eyes more. What there wasn't on the drawing is the template for the dihedral angle. easily made by drawing out the dihedral brace.

 

I'm going to go ahead with the wing as it is. I have looked at it again and again and the angle on both halves seems to be the same. Guess I made the same mistake twice. It should still fly but I will need to reenforce the joint.

 

Looking to the future!

[Alex Whittaker]

Shane,

Utterly fascinating.

Alex

[Shane Sunday]

Well I've had a couple days to build and boy did I ever. This is a pretty simple build but there are things that will make you scratch yer head. Especially when you're building out of depron. I got the fuse all put together much the same as you would with any build so I'm not going to bore you with the details. I did need to find a way of strengthening the depron where the elastic bands are concerned as well as keep her light weight. So I used plastic card. i was a bit apprehensive but it works real well.

Ok all my images are getting put on top so I'll just have to go with it and not bother trying to do a running commentary with photos in series. Anyhow... One ove the best purchases I have ever made was my SLEC balsa stripper. All of my stringers were made useing this and they are all 6mm dead on. Don't start a build without one.

So then it was time to start on those tail feathers which were also made of Depron woohoo! There are 2 thicknesses here though 6mm and 2mm laminated on top of one another via double sided sticky tape. Also with a couple 4mm carbon rods sandwiched in between for good measure. I cut and made channels so the rods would fit snug. I then cut the elevators and did the 2 ply thing but this time I added a 6mm hollow carbon rod to act as the pivot point which is then taped to the horizontal stab. It might look rickety but I assure you it's rock solid. I used the same technique on the vert stab but with the rudder I just chamfered the edges of the stab and rudder and tapped them together. The move freely and oh so smooth. I then finished off the bottom of the wing and mounted my servos as well a skinned the bottom with 2mm white depron and checked the seat on the fuse. I hade to notch the TE of the wing to get it to sit right as well as had to add 1/32 light ply to the TE as a support, I don't want those elastic bands wrecking my wing. But I got it all to go together nicely and so far I just love it.

 

I've done the hatch cover but haven't sorted how I'm going to mount it yet. Once that is done It's time to work on the UC.

 

Hey Alex I'm glad you find it interesting. Thanks.

 

Oh one other thing the weight so far is 1lbs 8oz. While at the moment I wouldn't want to smack it into a tree after I get the thing covered I won't be so worried. Not too bad for floor insulation i'd say.

[Shane Sunday]

 

 

 

 

 

Hey guys I have finished the build portion next is the maiden then cover and paint. I want to maiden it first so I can correct anything that might need it. My bug might not be the prettiest over built but that's why I'm calling it the bug on my TX. I just hope it will jitter a little as well.

 

One of the things I had to get sorted was the hatch. How was I going to set it in place? This was one of the few deviations I made while building it. I knew I wanted to use magnets and also a lip on the fuse as an anchor point and I came up with the image above. I first built the hatch and covered it with 2mm white depron then built the side walls of the cockpit to accommodate my hatch. So the hatch slides under the acetate canopy into the recessed lip and then I inset some button magnets into some braces, taped them down, laid the hatch magnets ontop of the tape and pressed the hatch down firmly to get my location dead on. Too many times I tried measuring and got it wrong in the past. I then used a 6mm bit and useing my fingers only drilled out the holes for the magnets in the hatch. Laid some tape sticky side up onto the fuse magnets and placed the hatch magnets ontop of them. (Confused yet?) Me too but the pics say it all really. I then put the hatch in place and pressed down firmly so that the tape would stick to the hatch. I used my knife to assist in this. and viola one secure hatch.

 

Next was onto the UC. I started building wire ones as per the plans which were working out great albeit a little slow on the build side. When I looked up and saw my trainer. Poor old thing... Never gets used any more. So I tore the bloody UC off it and and slapped it onto the nice shiny new, going to get lots of use BUG. I thought it would be a bit heavey for a depron model but turns out it is helping with the CoG. Woohoo!

 

Tomorrow night I'm putting on all the control rods and checking how she handles on the ground. Oh ya I also need to put on a tail wheel or a drag bar.

 

AUW with 2300 lipo a whopping 2lbs 14oz. My motor is offering up 320 watts of power and 29 amps with a 10x7 prop. I might try a 11x5 and see if I can get that motor closer to it's factory rate of 35 amps. Now if I can only get a day off and a lot less wind. This country is coming down with it.

 

Cheers

 

 

[Shane Sunday]

well the weather has been crap here lately what with all the rain and wind we have been getting so no chance to maiden this bad boy. I'm looking forward to it too. So while I have been waiting I decided to glass cloth and polyc the thing then paint. Here is a pic of her all painted up.

 

[Shane Sunday]

Hey there guys.I had a reprieve in the weather after work yesterday and I was able to maiden the bug.

Alex I'm sorry man I would like to say that it was good but the plan just is off. No not really. I got to my local field and set it up, did all my checks and gave her some throttle and away she went. It took just a little right rudder to keep her on track and about 3 meters with a touch of up elevator and she was away on 3/4 throttle. To be honest it would have left the earth with half throttle. Not too bad for a 3 lbs model. A circuit or two plus a touch of left aileron and down elevator to trim her out and she was flying beautifully. For the first flight I always have the jitters (no pun) so I didn't do much more than get her flying level then landed. I'll say this she really wants to float. The first landing was a bit off and I ended up bending my wire UC. The depron was unscathed.

I had about 5 flights with it and recorded the 3rd didn't do too much cuz it was hard to see with the sun going down and sunglasses on with camera mounted but rest assured she loops and rolls very well. The stall on this depron model is not an issue. Over all I am extremely happy this is going to be a lot of fun. Thanks for a quick to build yet fun plan Alex.

here is the video.

 

http://www.youtube.com/watch?v=Yd-IHP9aihg

Edited By Shane Sunday on 20/05/2011 11:04:04

[Alex Whittaker]

Shane, you're a star! Your video arrived on my birthday, and it made my day. Well done. I think that Foamie JItterbug is a real achievement. Very neat finish too. I must say I am rather chuffed that you have built a version from foam, and 'leccy powered too. That really is "proof of concept" - different construction AND different power delivery. RCME readers are an inventive lot. The video is now one of my all time YouTube favourites, Also, I didn't realise that you were Canadian, until I heard the voice, and saw the Maple Leaf. By the way, I have just finished another free plan. It's a triple function / dual fuel project - a .25 sized aerobat expressly designed for 'leccy and glow, but its also convertible to a control line stunter, with coupled flaps and elevator.

Once again, well done.

Alex

[Shane Sunday]

Happy birthday then Alex and congrats on designing a great flier. I look forward to the next but up next is a stuka from depron.

 

Just a few specs on the motor

EMP 3542/06

11x7 prop

40 amp OPTO esc,

switching BEC

2300-3700 lipo's

 

Drawing 27 amps 316 continuous watts. on 3700 mah lipo

 

I was worried it wasn't enough but it moves quite nicely. So if you want to build out of depron this is a good motor to start with. It could use a lil more power but really doesn't need it.

[Tim Mackey]

We just need to educate him how to use the copy and paste function correctly now

Happy birthday Alex

[Tom Wright 2]

Here you go.....

 

[Foamie Dave]

Great job Shane

I keep telling Whitty that b*lsa and n*tro will never catch on but he won't listen...perhaps this will bring him to the dark side !.

Crackin flyer mate!

 

Oh ..and happy b/day Al !

[Shane Sunday]

Balsa? Nitro? What are these things you speak of?

 

Thanks Dave I am well happy with the BUG. Last night when landing I got blasted in the eyes by a low sunset and lost her. It was about 7 or 8 feet from the ground, she rolled and went down hard. Motor mount held F2 came away, f3 held f4 came away and a couple stringers broke. Wing tip slightly dented.

 

Took it home less than an hour later good as new! I love DEPRON!

 

Still doesn't want to come down. I've re enforced the UC so they don't bend so much can't wait to get her up again.

 

[Shane Sunday]

Hey guys thought you might want to see a little more interesting flight with the Jitterbug. I live in Belfast and being Canadian people love to chat to me aboot it. I dunno why eh? I must smell like maple syrup or sumthing. Anywho, I've had a couple people comment on the paint. Sure it was just wacked on there but it is very visible. Yesterday the winds were high early afternoon and I had a hard time landing plus a couple near incidents with the ground due to the wind. I have since learned what the air speeds are for landing this bad boy. I need to bring her in on a quarter throttle then flair out at the last min to get smooth landing. None of these are in the videos I've posted but as the day went on I did manage to get her down nice and smooth.

 

I've found that with depron anyhow she can float to just about 5 foot off the deck before any up elevator is need and then flair. Then she just rolls in. Because she is so light wind really effects her. Anything over 13 mph is going to be a hairy ride for a depron model even one this size.

 

I cannot recommend this model more. If you want a sports hack, something spirited, cheap n easy to build that looks good in flight then do yourself the favor and build this one. If weight is an issue then do like I did and build from depron. It only took me a couple weeks but could have easily taken a weekend of solid building. It was that easy. And honestly it's so much fun.