Posts: 373
Joined: 11/16/2003 From: Doncaster, UNITED KINGDOM Status: offline
You know you should have a dust mask on while sanding epoxy - or any resin for that matter. For some people it can be very serious indeed
Looking very nice Scott. I have to say there is a temptation for me to have a go at an electric Lancaster. I was at a scale event at RAF Coningsby recently and there were 2 1/7 scale electric Lancaster’s there. Fantastic lookers in the air.
Posts: 342
Joined: 1/25/2002 From: San Diego, CA, USA Status: offline
Those lancs look really nice. What is the wing span on those and are they plans I can buy or did the owners come up with their own? Maybe after a lanc break I'll come back and make a bigger one.
Tonight was hatches and more filling around the wing joint. The pictures are of the hatches since more pictures of micro-balloons doesn't sound to exiting to me. I tried the magnetic route this time. The magnets are rare earth from Radio Shack. Pretty small and seem to hold on tight. The real test will be in the air...
I need to fiberglass the three hatches (two by the tail wheel for access) and the little fairing by the tailgunner. After that I think I'll be ready for some primer. That'll be a nice milestone to cross.
Posts: 13
Joined: 10/25/2003 From: leicester, UNITED KINGDOM Status: offline
Hi,your build looks great.I have the new 2006 plans for this plane and noticed something.When you get to building the cowls,you make a plate for the back.Believe it or not that is almost exactly how the 2006 plans show it. How is your build going,have been enjoying watching it.
Posts: 342
Joined: 1/25/2002 From: San Diego, CA, USA Status: offline
Still chuggin along Mike. I try to do a little every night after my son goes to bed. Even if it is just a bit of sanding. If I don't commit to just a bit each night it's pretty easy to let it slide for a month and get nothing done.
I have glued on the vertical stabs. The second one just needs to set up overnight. I wasn't thrilled about the butt-joint to the horizontal stab so I pinned it with two toothpicks. The toothpicks also made it easier to keep everything in position while the epoxy set.
Also, this week I decided to re-think my power setup. The old plan was a 5S1P pack running the motors serial parallel. For this setup to work I needed 2.3:1 gear boxes. The ones I got turned out to be 2.6:1 which I didn't realize until I did the motor run-up a couple of weeks ago. With that gear I was only getting about 4600 RPM on my Master Airscrew 9x7 props. This seemed like the pitch speed was going to be marginal at best.
After talking to my local electric guy I decided to try one of the motors on three cells. This test showed the motor pulling about 12 amps at full tilt and turning the prop 5600 RPM. Much better. So now I was left with the 5 cell pack when I really needed a 3S2P. Unfortunately, they did not have a spare cell that I could solder on and, it turns out the cell uses a circuit board type connector anyway so that would not have worked so well. I ended up buying a four cell pack from them and converting it and my five cell pack to three cells. I had to dremel the circuit board but they seem to have survived the surgery.
I now have 3 single cells I can wire up into a pack which will get me half the way to a second flight pack.
So the new power system is as follows:
two 3 cell 4000mah lipo connected in parallel. Medusa Research 50AMP speed controller with BEC. Four speed 400 2.6:1 gear box/9x7 Master Airscrew cut down to about 8 3/4x7 (scale size) all parallel.
This should draw about 48 amps at full go and be well over 400 watts.
Posts: 342
Joined: 1/25/2002 From: San Diego, CA, USA Status: offline
I couldn't help myself. Tonight I bolted everything on just to see how it was looking. I also took the opportunity to weigh the airframe and all of the flight equipment. The total comes to 6lbs 4oz. If I can keep the finish (just primer/paint) to a couple of ounces I should finish this up right around 6 1/2 pounds. I calculated the wing area at 4.33 sqft which leaves me with a wingloading of 24oz/sqft. That seems pretty tame to me. So I'm hoping for a good flier.
Posts: 5
Joined: 5/21/2006 From: plymouth, UNITED KINGDOM Status: offline
Hi Scott' Must say Your Lanc is looking Fantastic, coming along really well. Those lipo's are really helping to keep the weight down. The 10 cell 3500mah nihm's i used to fly my Lanc weigh a full 1 1/2lbs on their own! The three bladed props look excellent, have you measured the amp draw with them fitted I'd be interested. Take care and keep at it bud, Walts
Posts: 342
Joined: 1/25/2002 From: San Diego, CA, USA Status: offline
I measured one motor on a three cell pack. With a 3 blade 9x7 master airscrew prop it drew 12 amps at full throttle. I cut the props down to closer to 8in so they would be the scale diameter but I have not retested since that was accomplished. I expect total amp draw to be less than 48. My pack is good for up to 56 (7C).
Posts: 5
Joined: 5/21/2006 From: plymouth, UNITED KINGDOM Status: offline
Only 12amps, that sounds good. I was expecting it to be much higher with those props. I'd like to do the same thing on my one once i refit it with the brushless motors. The motors are more than good for it but my NIMH battery might suffer a bit. I intend to start the conversion this week hopefully.
Posts: 342
Joined: 1/25/2002 From: San Diego, CA, USA Status: offline
Thanks, I'm itching to get it done too. Our club has a scale fly-in in three weeks, but at my pace I don't think that is going to happen.
I'm down to diddling with all the minor things to clean up prior to primer. Mostly, more sanding. Tonight I was just cleaning up the holes in the bottom of the horizontal stab so they weren't so nasty looking.
On the side I have been trying out the dupli-color primer on my polycrylic test piece. So far that seems to be going fine.
Posts: 342
Joined: 1/25/2002 From: San Diego, CA, USA Status: offline
Another nice looking lanc. Keeps me motivated to get this one off the bench.
I had to make one more hatch for access to my air filler and the arming switch. Instead of putting a hole in one end that I could get a bent wire in to pull it open, I set it up so you can push on the leading edge of the hatch and pop the magnet off. This one is located just under the leading edge of the left wing (the lanc is upside down for the pictures).
Once that was out of the way I got to some priming. I sprayed on a heavy coat and now I'm about half way done sanding it down. I found some spots where my epoxy/micro-balloon seams are lacking so I may go back and revisit them before the next coat. I guess it just depends on how picky I'm feeling when I get there.
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RE: Electric Lanc Build - 
