Espritmodel.com Telemetry Radio
Reply
Thread Tools
Old Feb 14, 2013, 04:26 PM
Fort Worth Thunderbirds
Joined Jan 2013
91 Posts
no...that's correct for a 12 bladed fan.
Sunbyrd is offline Find More Posts by Sunbyrd
Reply With Quote
Sign up now
to remove ads between posts
Old Feb 14, 2013, 08:28 PM
Registered User
Singapore
Joined Nov 2007
434 Posts
OMG something is wrong, my fan recorded 86 Amps and that was not on a freshly charged pack. I would not suspect the e-Flite connectors as I am sure that they are up to the job, 1 kW drop across a connector and it would be like a electric fire..!

Were you able to take a record of Volts from the data logger.?
dennisp_sg is offline Find More Posts by dennisp_sg
Reply With Quote
Old Feb 14, 2013, 09:53 PM
Fort Worth Thunderbirds
Joined Jan 2013
91 Posts
The eRC ESC doesn't have a data logger function but that's a moot point now.

I finally figured out what the problem was and I feel like a total idiot now! DOH!!

The memory space that I'm using on my Futaba transmitter was used before for a nitro model. The throttle travel end points were set to less than 100 percent and I failed to sync the ESC to the current end points.

I set the end points back to 100% for off and full and guess what..it immediately blasted to 1800 watts and started dragging the test bench across the garage floor so I had to shut it down before going full throttle. YEA!!!

Tomorrow, I'll test the other ESC's and motor.
Sunbyrd is offline Find More Posts by Sunbyrd
Last edited by Sunbyrd; Feb 14, 2013 at 10:02 PM.
Reply With Quote
Old Feb 14, 2013, 10:05 PM
Registered User
Singapore
Joined Nov 2007
434 Posts
Well done sir, perhaps I am lucky as I always start with a new model memory in the Tx, so everything is 100% travel each way, but if you are using a existing one oop's I suspect you will never fall for that again...!
dennisp_sg is offline Find More Posts by dennisp_sg
Reply With Quote
Old Feb 17, 2013, 10:11 AM
Fort Worth Thunderbirds
Joined Jan 2013
91 Posts
Now that the throttle issue is resolved, I did some more motor testing this morning. The RC Lander 90mm 12 Blade 1620kV managed to overheat the Hobby King 120amp ESC in just under three minutes. The ESC was mounted in the airstream of the fan. So, I'm positive it was getting enough air flow. I was only running around 1000-1200 watts and around 80 something amps when it started shutting down.

So next, I went back to the RC Lander 90mm 5 Blade 1900kV and ran that with the eRC 115 amp ESC. At max it put out 1815 watts and never pulled over 87 amps (advertised watts is 1750). I ran it for over five minutes, jockeying the throttle up and down to simulate flying conditions but mostly kept the watts around 1200. The ESC never overheated.

Both the ESC and battery were warm but not hot. In both cases, the battery was a fully charged 45C 5000mA Zippy Flight Max.

The RC Lander 5 Blade 1900kV will be mounted in the fuselage today, which was the original plan anyway. The Landing gear is all set up and I'll be ready to mount the rear half of the fuselage withing a few days.

Progress!!

I guess I'll save the 12 Blade fan for my fiberglass MiG-15...if I ever get a sufficient ESC for it.
Sunbyrd is offline Find More Posts by Sunbyrd
Reply With Quote
Old Feb 17, 2013, 10:32 AM
Registered User
Singapore
Joined Nov 2007
434 Posts
Glad to hear that you are now making good progress, I hope that the rest of the build goes smoothly for you.
dennisp_sg is offline Find More Posts by dennisp_sg
Reply With Quote
Old Feb 20, 2013, 10:06 AM
Fort Worth Thunderbirds
Joined Jan 2013
91 Posts
I mounted the fan, today. But the original location with the modified (cut off) tail cone/shroud still put the spinner perilously close the safety screen. In order to move the fan a 1/4" rearward, I had to abandon the tail cone. So, I'll be going with the eFlux finned heat sink.

Since there's nothing to lock down the heat sink and the motor is coated with a film of slippery thermal compound, what keeps the heat sink from being blown off the motor?
Sunbyrd is offline Find More Posts by Sunbyrd
Reply With Quote
Old Feb 20, 2013, 08:55 PM
Registered User
Singapore
Joined Nov 2007
434 Posts
The heat sink should be a tight fit on the motor can, sounds like yours is the wrong size.?
dennisp_sg is offline Find More Posts by dennisp_sg
Reply With Quote
Old Feb 20, 2013, 09:29 PM
Fort Worth Thunderbirds
Joined Jan 2013
91 Posts
No...it's the right size. I had to hold it open just a bit to slip it on. I'm just concerned that it has no mechanical locking-on(?) and that the friction that's expected to keep it in place has got to be diminished by the thermal compound.

Have you flown yours with the heat sink held on by nothing but tension of the aluminum?
Sunbyrd is offline Find More Posts by Sunbyrd
Reply With Quote
Old Feb 20, 2013, 09:34 PM
Registered User
Singapore
Joined Nov 2007
434 Posts
Yes no issues always stays in place.
dennisp_sg is offline Find More Posts by dennisp_sg
Reply With Quote
Old Feb 20, 2013, 11:08 PM
Fort Worth Thunderbirds
Joined Jan 2013
91 Posts
Okay, thanks. That's good to know. The motor is mounted and the rear half of the fuselage is completely done. Servos and control surfaces installed. Push rods made and wires run. Just needs some of the wrinkles ironed out and decals applied and it's ready to mate to the front half of the fuselage.

Not a whole lot left to do. Spring is typically the stormy season in Texas but I'm hoping to maiden it before the end of the month or shortly thereafter.
Sunbyrd is offline Find More Posts by Sunbyrd
Reply With Quote
Old Feb 21, 2013, 12:00 AM
Registered User
Singapore
Joined Nov 2007
434 Posts
Well done sir, we are still in the rainy season here in Singapore, flying field is still a pond AIYO.
dennisp_sg is offline Find More Posts by dennisp_sg
Reply With Quote
Old Feb 23, 2013, 10:56 AM
Fort Worth Thunderbirds
Joined Jan 2013
91 Posts
Well, I thought I was almost done. When I tried to balance the plane's CG at 50mm, I found that the main gear were indeed in forward of the CG and it would only sit on it's tail. This is an issue that has been widely discussed in this forum, but I had to see for myself. I sure hope that Nitro Planes is paying attention to this.

I had some 40-60 sized glass-filled nylon landing gear from which I could make new main gear legs. I believe these are so old that they're the Roy Klett landing gear. And, they're different from the newer Goldberg 40-60 glass filled nylon gear. On the newer Goldberg version, the legs taper evenly towards the wheel axle. On the older Klett version, the trailing edge is perpendicular to the base and the leading edge tapers back toward the wheel axle.

By cutting down the Klett landing gear, I can effectively move the main wheels back 20mm, raise the fuselage 10mm and widen the track one inch on each side. That's all the good.

The bad is that the when the gear is cut in half, the remaining base of each leg is only wide enough to use two of the existing screw holes. Which means either go with only two screws on each leg or figure out a way to use a third screw. The way the plywood gear mount plate is located inside the fuselage, there's no easy way to install a blind nut. I'll have to figure something out for that.

I sure hope moving the main wheels rearward by 20mm will allow it to sit on it's nose wheel properly.
Sunbyrd is offline Find More Posts by Sunbyrd
Reply With Quote
Old Feb 28, 2013, 10:44 AM
Fort Worth Thunderbirds
Joined Jan 2013
91 Posts
Had a major setback, yesterday. The FT was finished and ready for its maiden flight. But I decided to test and see how much actual thrust I was going to get. I staked the plane to a digital fishing scale and ran the motor up. After about 30 seconds, there was a loud pop, the motor shut down and smoke started pouring out from under the canopy. Luckily, I had the foresight to have a fire extinguisher near by. I was able to get the canopy off pretty quickly and douse the flames...yes, flames...burning around the ESC.

This was my 115amp eRC ESC, that supposedly has temperature protection set at 110 degrees Fahrenheit. It's supposed to shut off when it reached that temperature...obviously, it didn't.

Now, I would have thought that with the cooling vent hole cut in the bottom of the nose and the fan located behind the opening in the fuselage, that the fan would have sucked sufficient air through the fuselage to remove the excess heat. WRONG!!

Also, I know for sure that the motor doesn't pull more than 90amps. I think 87 amps was the highest that was registered in my previous tests on the bench using my watt meter.

Luckily, the receiver and all the other electronics survived. The receiver battery got toasted on one corner and is probably no good anymore. The Zippy Flight Max battery makes crackling noises when you run your fingers over it, so it's probably no good either.

However, since there appears to be no major structural damage and believe it or not, not external cosmetic damage, I'm going to give it one more try. This time I'm going to mount a 190/200 amp ESC underneath the fuselage. How much more cooling is possible than that?
Sunbyrd is offline Find More Posts by Sunbyrd
Reply With Quote
Old Feb 28, 2013, 06:32 PM
Registered User
Singapore
Joined Nov 2007
434 Posts
Sorry to hear the bad news, I have say that my experience with cheaper ESC's has been much the same which is why I moved to Castle Creations. The good news is the warranty and repair on their items is good, OK you pay a price for that, but in your case the shipping within the US is nothing compared to shipping from Singapore. I hope the next test with the new ESC that you have ordered is a success.
dennisp_sg is offline Find More Posts by dennisp_sg
Reply With Quote
Reply


Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
Cool pictures of fan flying off EDF-50 unit. hsuusa Parkflyers 1 Jul 08, 2002 03:43 AM
Fan-fold foam EDF Vincent Electric Ducted Fan Jet Talk 8 Jun 19, 2002 06:20 PM
My new jet trainer for EDF 300 kwan Electric Ducted Fan Jet Talk 3 Jun 26, 2001 06:54 AM
Where's the Fan Trainer by Steve Neil? rcdude Electric Ducted Fan Jet Talk 11 Jun 06, 2001 02:42 AM