2015 Project #1- Electric "Weston UK Velocity 50" THE BUILD

[Derek]

Thanks a lot, guys! I got the black squares taped to the belly of the plane last night. It looks really sharp. I didn't get any bench testing done of the motor/esc/props this weekend because my daughter has a wicked cold and I've been tending to her a lot. I'll see about getting some bench testing done on my next day off.

[Derek]

Here is an update on my Velocity 50 build. It is complete and everything is functional. The two Futaba servos are very strong and smooth. The YEP 150amp esc is calibrated, programmed, and seems to be working properly. However, I will probably have to wait to do the maiden flight because my only 45C 6S packs are doubled up for my Trex 600. I do have two 6S 3000 20C packs that I run on my Trex 500 and a 6S 3000mah 35C pack that I run on my 600. I'm just afraid that the motor on my Velocity 50 build will kill these batteries. I'm going to order a pair of 45C packs, hopefully, this coming week. I'm hoping to find a higher C rating but Buddy RC has some great prices on their 6S Glacier packs.

[pvolcko]

Nice. Eagerly awaiting this one getting completed and tested.

[Derek]

Thanks Paul! Im eager to give this plane a rip, too. I just don't wanna toast one of my good batteries, so Im waiting to order suitable batteries that will handle the load. I think its gonna be a pair of Glacier packs.

[Derek]

Ok...I've done some bench testing.

With the throttle curve linear and an 8x4 and 8x6 APC prop, the YEP 150 sec trips out. Tried some 7" props and the sec trips out. Ok...I changed the throttle curve so that its linear to top out at 75% and tested some props. Here's the results

8x6 APC - 1993 Watts
8x4 APC - 1993 Watts
7x6 APC - 2047 Watts
7x5 APC - 2043 Watts

My watt tester maxes out at 99.9 amps. Each prop test went over the 99.9 amp but did not trip out the sec. The esc was a bit warm but I imagine that was because the motor was being worked one test after another with no air flow. On top of that, I imagine the amps will be lower, in the air, because the motor isn't working as hard as it does at stationary on the bench.

As the plane sits, it is ready for flight testing but I am going to wait until I can add a bec. In thinking if the esc does fry in flight, the bec should allow me to "hopefully" still have control to glide the plane down safely. If the esc does fry without rx power, this will become an out of control 5lb missile. I'd like to think that I'm smarter than that.

I have a Castle 10amp BEC ordered. Should be here early next week. I'll get that soldered in place and we'll plan for a maiden flight next week.

[Tony]

That's a good idea D, better safe than sorry mate...

[pvolcko]

Interesting. I would have expected the 7in props to clock in a lower wattage.

[Derek]

Interesting. I would have expected the 7in props to clock in a lower wattage.

Me too. Do you remember my original thoughts of 10" props? Push! So much for that lol

[pvolcko]

Like you said, if it's in motion the drag on the prop should be far less. You may well be able to run 10" so long as you're slow and smooth with the throttle. Maybe program in a rate limit in your TX, if it supports it.

[Derek]

What do you mean "rate limit"?

[pvolcko]

Some transmitters have a setting on channel setup where you can adjust how fast they will allow the channel to change value. Usually it is used on switch activated channels to slowly ramp between a 0 and 100 value, such as for slow deploy/retract on landing gear or flaps. You could potentially set it up to prevent fast upward changes on the throttle channel but possibly still allow you to chop to a lower value without any effects. This way you would not be able to spike the current draw with a fast upward change on the throttle stick.

I'll see if my DX9 and DX7S have it and if they allow using it on throttle channel. If so I'll see about making a quick video.

[pvolcko]

So, DX9 has it and DX7S does not. I suspect DX8 does. It's possible the new DX7 does, too. Maybe new DX6, as well. They may have also opted to hold this feature from the DX7 and lower models.

20150810_221443_resize.jpg (134.39 KiB) Viewed 6602 times

Go to servo setup menu

20150810_221458_resize.jpg (131.36 KiB) Viewed 6602 times

Highlight the "Travel" option and scroll it until it says "Speed".

From there check out this vid of two different positive direction settings:
http://youtu.be/MvMVQTXn20c

The video is still uploading so you may need to wait a few minutes for it to complete and to processes before it is available.

[Derek]

That's interesting! I may have to mess with that and see what I get. I think I've seen that function on my DX8.

[Derek]

Originally, this plane was to be a project plane for 2015. Well, here we are, in 2016, and the plane was 100% done but then it's been suggested to me to taper the trailing edge to help reduce drag and to help with stability at high speeds. So, that's what I'm going to do.

In the meantime, here is an overview video of my scratch build "Weston UK Velocity 50"

https://www.youtube.com/watch?v=rdWbrnPvrUw

[Graham Lawrie]

My new DX7 has the speed function:)

[Vipertech13]

Just watched the video. I can't wait to see this monster take to the sky!