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| Electric Flight Discuss Electric Flight in Canada |
Topic Review (Newest First)
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| 12-20-2012 08:29 PM | ||
| OLD PRAIRIE RED NECK |
Re: Electric conversion of my #1 FPV ship, Kadet Sr. Looking good Max! |
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| 12-20-2012 08:11 AM | ||
| Max |
Re: Electric conversion of my #1 FPV ship, Kadet Sr. Well, its show time! The covering was re-shrunk and new covering added to the front of the fuselage. I haven't gotten around to painting the cowl yet, but I was itching to maiden it!  Here she is just before the maiden: For the hatch, the easiest idea I could come up with was a velcro strap on the hatch and on the side of the fuselage. Easy as pie Right now, a tape hinge is on the other side holding the hatch on Nothing left to do but fly! Power is a 5000ma 5S battery and a 70A ESC. On maidens I also use my Eagletree Datalogger to measure voltage, current and cumulative Mah. This is always helpful on the first flight as it allows me to assess the power consumption and helps me determine if I am over/under propped, as well as what my expected run time could be. Popping it into the battery bay via the hatch was super simple and effortless. Even the datalogger went into the huge battery bay with no effort at all. I also plugged in a battery alarm set to 3.5V/Cell to let me know when I should land. Range check and she was ready to go The take off was AMAZING. I hit the throttle and the beast LEAPT into the air with a run of about 6' It was WAY over powered so I pulled the throttle down to about 1/2 stick Even at half stick, it climbed very quickly, and in seconds I was already high enough. I pulled it down to "cruise power", a throttle setting that I could tool around with. Looking at my TX, I was at about 40% throttle. For the purpose of the datalogger, I try to hold throttle settings to get a good reading on power consumption. After a few minutes I went to "climb Power" and again, looking at my TX, I was only at 50% throttle. Then back down to cruise power and tool around the sky I noticed that even at 40% throttle, wind penetration was excellent and I was making good ground-speed in spite of the moderately strong headwinds. After what seemed like forever, I finally heard the battery alarm beeping (3.5V/cell while under load) I took that as my cue to land. Time elapsed was 21 minutes! Battery check after landing was 3.74V/Cell and the battery was barely warm to the touch! Excellent!! Here is the flight data recorder showing power draw and other data: Based on this log, I can see that at cruise power, I only draw 10A The spike at the 4' mark is where I went back to climb power; 25A At the end of the flight I used 3600ma from a 5A battery and still landed with a pack in very healty condition, 3.74V/cell. This is going to be a great winter FPV plane!!!
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| 12-18-2012 11:21 AM | ||
| Max |
Re: Electric conversion of my #1 FPV ship, Kadet Sr. I did some carving last night. I find the best way to do it is to grab a chunk of foam and cut the front-back length to match the distance between the firewall and the spinner. Then I use a knife to hollow out the inside just enough to get the foam to sit onto the plane. At this point the block is larger than the fuse. Then going by eye, I carve the outside of the foam until it gives me a nice cowl shape, then sand. Then I remove the cowl from the fuse, and remove more foam from the inside until you get enough clearance all around. Its simple and its quick! Here she is all done up: It still needs some paint but I will do that later. Maybe after the maiden. All that's needed now is some covering, install the hatch and we are good to go
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| 12-18-2012 11:14 AM | ||
| Max |
Re: Electric conversion of my #1 FPV ship, Kadet Sr. Quote:
On my PBY electric, it has a front top hatch that isnt exactly waterproof. For that plane I pre-taped both sides of the hatch (its a foamy) with clear tape. That tape is permanent and acts to protect the foam from the next layer of tape; The next layer of tape is temporary and sits on top of the permanent layer. How it works is this: I pop a new battery and close the hatch. Then I use Cheap-o scotch tape (1/2" roll that comes in the plastic dispenser) and I seal up the hatch. The tape straddles the opening in the hatch and rests on the permanent tape on either side of the hatch. On the ends of the scotch tape I fold the over on itself to act as a pull tab, and when the flight is over, I peel of the scotch tape. All is nice and dry inside
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| 12-17-2012 09:04 PM | ||
| OLD PRAIRIE RED NECK |
Re: Electric conversion of my #1 FPV ship, Kadet Sr. I am still taking the wing off to change batteries. I considered the bottom hatch solution but rejected it due to the fact that I do a lot of float flying & that would be an entry point for water spray! |
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| 12-17-2012 02:38 PM | ||
| Max |
Re: Electric conversion of my #1 FPV ship, Kadet Sr. Quote:
Yeah, I naturally leaned towards "lots of room in the fuse when the wings are off.. just drop the batteries in there" But... I'm Lazy!..LOL Also I didn't want a situation where I had to get the batts out in a hurry and have to remove the wings to do so. Doorskin is the miracle wood for scratchbuilders. I used to buy Mahogany doorkskin years ago but that is no longer available. Oak doorskin is all I could find today, its just a wee bit thicker and a wee bit heavier. But in the big picture, most people wont notice the difference. I have been using oak for the last year and I dont really noitce a difference in the end. The last oak doorskin I bought was a year ago. I got a 4x8 sheet for about 15 bucks. Thats good for 2 or 3 airplanes at least 
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| 12-17-2012 01:07 PM | ||
| davidmc36 |
Re: Electric conversion of my #1 FPV ship, Kadet Sr. Nice deal. I never thought about door skins before. Will have to ask the facilities guys if they have any busted ones that I can have a few pieces of. I really wish I had spent the time to make an access hatch in the bottom of the Kavalier. Taking the wings off is a pain in the butt. |
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| 12-17-2012 11:54 AM | ||
| Max |
Re: Electric conversion of my #1 FPV ship, Kadet Sr. Now on to installing the motor to the fuse. The first job was to decide how I would access the battery bay. I decided that I wanted to be able to be access the battery with the plane fully assembled. I could have resorted to removing the wings to swap batteries, but I didn't think that was going to be feasible. I did not want the chore of constantly removing and attaching the wings between each flight. I also didn't want to weaken the structure too much by adding a battery access hatches that would take away from the overall strength of the fuselage. So the best idea I could come up with is an access hatch on the bottom of the fuselage. I cut away the bottom section of the fuse all the way back to the first brace, which was about 4" back from the firewall. This also gave me excellent access to the motor mount and ESC For the hatch, I took a piece of 1/8" ply oak doorskin and cut it to shape. I use doorksin for a lot of my projects. Doorskin is strong, light and inexpensive. As a matter of fact, the fuselage from this plane was cut from doorskin when I first built it back in '88 Now the motor was attached. It went on really fast, without a hitch. Now it needs some covering. I might even make a cowl for it
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| 12-14-2012 12:41 PM | ||
| davidmc36 |
Re: Electric conversion of my #1 FPV ship, Kadet Sr. I like that hat-section mount for the motor. I made one like that on the brake at work for the Sig Kavalier E-Conversion. |
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| 12-14-2012 12:38 PM | ||
| davidmc36 |
Re: Electric conversion of my #1 FPV ship, Kadet Sr. Quote:
Then I wanted to try again a few years ago when I started seeing lots of electric at the field and guys having balls of fun with LiPo and brushless. Got the E-flite 15 Bonanza and never looked back. That baby is a real sweetheart. So much that you can do with electric now. One guy at the field has a huge bipe with a motor as big as your head!! 3D all day!! Still though, looking back I wonder how the Cub may have been with a bigger prop. I only ever tried the one it came with and I think it was only the size that the glo engine would have used. If it could have handled the amps maybe it would have flown decent. Not likely would have lasted long with brushes though. Thank heavens for three phase AC and the advancement of speed controllers that produce it. |
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