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

[danhampson]

Keep us posted derek.

[pvolcko]

Sorry Derek, you're way outside my realm of knowledge here. But some things jump out at me:

2100kv at 6S is almost 50000RPM. There is no way you're getting a 10x6 prop to turn that fast. So either the motor will never come close to reaching that speed and will not draw insane current as a result of being stopped from reaching that RPM at full throttle (possible, I'm not sure how inrunner's behave electrically vs outrunners), or the prop is going to explode and quite possibly take the motor and electronics with it when it does.

What motor are they recommending/testing with? Are you sure it matches up specs wise to these two you are thinking of using?

Do you have a wattmeter? I think it is a necessity for this kind of experimental setup. You'll need your test rack (ideally setup for measuring thrust too) and I'd maybe get a handful of different props ranging from 4.5" up to 10" with the same pitch if possible (as close to the same as can be managed). I'd get pylon racing props, and even with those you're likely going to be blowing past the safety margins. Then try them out and making sure not to over stress the power system. You may be able to get away with the 10x6 prop but have to carefully use throttle so as to avoid spiking things into crazy current land. Basically slow ramps of throttle to let the RPMs catch up to throttle position and stabilize, then once you're at speed around 33-50% throttle you will be able to go full without much problem. I just think you're going to run into current spiking problems if you go full throttle from low or no throttle.

[Derek]

The rep that I spoke to, at Weston UK, said that they have been testing an electric version of the nitro "Velocity 50" and they were using a Tenshock EDF EZ2230 10T 2020KV Brushless-Motor, CC 100amp esc, and 10x6 prop. Although it is in German, here is the link to that inrunner:

http://www.osmot.de/tenshock-edf-ez2230 ... motor.html

Something I just noticed is that the two motors that I was looking at are 2200 watts and 2400 watts. The Tenshock shows 1750 watts. Perhaps I need to shop around for an inrunner that is closer to the 1750 watt range. I surely want this project to be a "screamer" but I also want it to be safe as well.

Yes, I have a watt meter and I use it on all my builds. It is rated up to 100amps. I like your idea of getting a range of props and then testing them to see what results are given.

[pvolcko]

Are they running this direct drive to the prop or using a gearbox? I can't believe they're running a 10"x6 prop direct drive off these motors. Is it a 10cm prop?

[Derek]

I do know that they are running it direct drive but I never thought to ask if it was a 10 inch prop or 10cm prop. 10cm is just under 4 inches. I can't believe the prop would be that small. Hmmmmm............

[pvolcko]

Pylon racers often use small props run at high speed.

[Tony]

Just been catching up on this project, way out of my league, but it all sounds very complex... Lol, best of luck with it Derek, looking forward to it's progress

[Derek]

Pylon racers often use small props run at high speed.

You are absolutely right, Paul! I wonder why the Weston UK guy told me that they were testing with a 10x6 prop.

So...in the interest of progression, lol, I'll just plan on buying a 7x6 and 8x6 prop for some testing. I have a bunch of 9x6 and 10x6 props. I have a watt meter. I'll be getting some foam and balsa soon for the airframe and I'll be ordering the electronics within the first two weeks of next month.

[Derek]

Just been catching up on this project, way out of my league, but it all sounds very complex... Lol, best of luck with it Derek, looking forward to it's progress

Thanks Tony! I'm really very excited about this plane. I think it's going to be massive fun. Instead of building just one airframe, I've decided that I'm going to build two...just in case, lol. That way, if something does go wrong on the maiden flight, I'll have the second airframe already built.

To be honest, it's probably a bit out of my league, too, just because of the speed that I anticipate from this plane but I believe in a "hands on" approach to learning, lol. Sometimes you just gotta roll up your sleeves and get then hands dirty. Chop, cut, glue, sand, paint and then fly. I love going back to Youtube and watching videos of the Weston UK Velocity 50 in action. Just awesome!!!

[danhampson]

Derek with that prop on one of those motors it should nearly max out the revs at full throttle.

[Derek]

Derek with that prop on one of those motors it should nearly max out the revs at full throttle.

Yep...it probably will. I'm gonna search around for a motor that is closer to the 1750 watt range and then I'll do some testing once it all gets here.

[Derek]

Ok, I'm gonna pop this thread up to the top again for a bit....

I've been doing some searching and doing a lot more asking (that's called research, lol)....

according to the places that I've talked to, as for the motor on this plane, I need to be looking for something in the "36mm Inrunner" area with 1600-1900kv and then run a 7x7 APC prop. I've been shopping around and there are actually quite a few choices to choose from. So, just as before....I'm quite excited about this project. I'll be starting to build the airframe this weekend (I hope, lol) and we'll get the electronics ordered as soon as possible.

[Derek]

Ha ha ha ha....I just happened to think that Paul mentioned that a 10x6 prop is probably not going to work for the power setup that I'm looking at for this project. Well Paul...perhaps you are more of a "plane-guy" than you thought, lol. I was just going off the info that I had gotten "originally" but after speaking with some other people, they are quite convinced that my prop choices are not going to be near the 10x6 range and they will more likely be near the 7x7 range and possibly 8x6 and 8x8. They strongly suggested that I do some bench testing with the 7x7 at first so that I can get some "starter" numbers (amps, watts). Maiden the project with the 7x7, possibly with the watt meter attached, and check those numbers. Then I will have some "actual" numbers to get a more educated guess on correct props to be using.

However, one guy that I spoke to (and a second guy agreed with the first guy), this project (with an AUW of around 4lbs, combined with this power system), said that this plane may reach speeds of over 150mph. That being said, he strongly suggested that I do the maiden flight with my throttle curve maxing out at 75%....then make adjustments as I get comfortable with it.

150mph!!!! Whoa!!! it's a good thing that I have recently found a MUCH larger flying field to fly at this year, lol. Not a public place. There are some trees and the parking lot but those will all be behind the designated "flight line" and I never fly behind myself.

[Tony]

It will be out of sight in a couple of seconds at that speed... Wow

[Derek]

Yeah....the fast passes will be awesome fun! Vertical climbs will be insane! I'm so looking forward to this!!!

[Derek]

OOOOOOOOOOOOOOOO, we're getting excited now!!!

I just ordered the motor and esc from Hobby King for this build. I ordered a few other things as well but I was able to get everything that I wanted from the closest HK US warehouse. "IF" they get shipped tomorrow, I should have them before next weekend...which doesn't really matter because I'll have to work next weekend but at least I'll have the parts. I need to hunt down a reasonably priced Spektrum rx and I want a satellite rx intsalled near one of the wingtips because there are going to be some wires inside the cockpit area and I'd like to have a satellite rx away from the internal wires and such. Probably something like an AR6210 with satellite would quite suitable. I was surprise that the US HK warehouse that I ordered from doesnt carry APC props so I'll have to order those from my LHS.

So....expect to see some build pics in the near future.

[Tony]

Your a busy man Derek....

[Derek]

I'm always up to something, lol! I'll post some pics when everything gets here and the build begins.

[Derek]

I just got an email notification that my order from HK has been marked as shipped. Very cool!!!

[Derek]

...because I'm impatient and all, lol, I checked on the tracking number for my package. Estimated day of arrival is this Friday. Whoo Hoo!!!!