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Archive for July, 2010
Posted by jbc | Jul 27, 2010 @ 10:34 PM | 20,119 Views
Here's a little SR71 made from Durable EPP foam. This thing is light, only 360g with 2S battery and is the perfect little park flyer Up close you can see it's not very detailed being EPP but when it's in the air it really does look the part, it is that unmistakable BLACKBIRD shape!
Let me also point out that the fact that it's EPP has saved me many times If you have ever flown an all black plane it is extremely difficult to orientate it once it has gotten more than a hundred meters or so away from you. After flying this I'm glad I never bought an expensive kit as I can tell you right now it would have kissed the dirt many times It's not that it's a hard plane to fly, just very easy to lose track of which way she is due to the colour in the air. If you've ever flown a black plane you'll understand what I mean.
The power system is perfect with the Emax 2805 outrunner giving around 100watts at about 12Amps with a 6x4 prop for this light bird.

A great little warm up plane to start the day off!
Posted by jbc | Jul 27, 2010 @ 01:50 PM | 21,998 Views
This is a cool plane! At first I was like oh yeah not bad, but then I changed the power system from a 700kv motor and 11.4,7 SF prop to a 750kv motor and 11x7 SF prop and this is now SAWEEEEET!!!! I bought the kit from Aerialhobby and thought I was getting the orange and white one but when I opened the box I got the yellow and black one. No matter as it still looked great and besides I didn't have a yellow plane

The build was relatively simple, the EPO foam is good and the power system I chose for it and installed, is the same as the Art-tech/Hobbyking Pitts is PERFECT and went in relatively easily. I had to use this stick motor mount which was fine and there's plenty of room behind the cowl to work with. The plane flies VERY nice, glides quite well(better than the Pitts) and is easy to practice your knife edges. The wheel pants and landing gear are a bit weak and I had to epoxy them on for strength. This will also nose over EVERY time on grass and everytime on anything other than a total perfect greased landing on bitumen runway. Alot of people remove em(wheel pants) but I think it wouldn't bee a GEEBEE without em I added a bunch of stickers and pilots head to it to try and make it look cooler too

With the power system I'm running I get a 1:1 thrust ratio and over 200watts or power for under 20Amps. I use a 25amp hobbyking SS esc and 11x7 SF prop. Excellent setup for this plane

GEE BEE RC plane (by Lan Yu) Flight & Box review (10 min 0 sec)

Posted by jbc | Jul 27, 2010 @ 01:26 PM | 18,817 Views

Here is the balsa model Fokker DR1 by Great Planes, I've always loved the look of the DR1 and finally decided to buy and build her. I bought the kit and decided to put my own power system in her. A word of warning though, if you decide to put any motor other than the recommended, you will run into problems with mounting it like I did.
I originally wanted to put a power system like that of my Art-tech/Hobbyking Pitts as it's perfect for this size plane, low amp and plenty of thrust. Hobbyking sell the motor but there's confusion as they list both a 700kv and 750kv motor as the one they use in their Pitts. I took a punt and ordered the 700kv and guess what???....I was wrong no biggy it proved to be an ok motor anyway and I just went up a size for my prop. I had to muck around alot to get it to mount at the correct distance and wouldn't recommend going this route unless you have alot of patience

The balsa build takes longer than your average foamie, the red covering film looks quite good and is surprisingly resistant against wear and tear

WARNING this plane is NOT for beginners! She does not taxi well, you must fly her with nice easy wide turns, and she has to be flown all the way to touchdown. No way can you just kill the throttle and glide her in. Even though she is a bit of a handful she totally makes up for it with how she looks in the air....GORGEOUS!

With a 1300 3S and 11x4.7 Slow Fly prop she makes around 200Watts for 17.5amps and around 1:1 thrust.

Motor 700kv
Hobbyking 25Amp ESC
11x4.7 SF prop
Posted by jbc | Jul 27, 2010 @ 12:35 PM | 17,603 Views
This is definitely one of the most fun planes anyone could fly! It is fast, the parkzone Z-foam is VERY crash resistant can also fly very slow, glides and simply turn up the rates and she's super maneuverable.

I got this in a swap with my brother and at first wasn't overly keen, then I took her out on a first flight and it was alllllll smiles from then on. I painted the top and bottom to make a big contrast as this thing can roll as quick as anything and it really helps with orientation. I originally had a 2200 inrunner with a 6.5x4 prop but burnt out the motor (was rated only to 32A).

This model is great to use as a warm up when going from prop plane to EDF. I have since put a new motor for even more speed and she has unlimited vertical. I can run it on 4S if I want but she balances nicely on 3S and I get plenty of power and speed as is, VERY HAPPY!

Following setup for 530Watts at around 42Amps is:

Turnigy 2836 2350kv motor
Towerpro 40Amp ESC
Turnigy 2200 30C 3S and Rhino 2250 25C 3S
6x5 prop
Posted by jbc | Jul 27, 2010 @ 10:36 AM | 17,871 Views
I bought this Big SAPAC JAS 39 Gripen foamie EDF off my brother. He flew it as a 70mm for a while and wasn't overly thrilled by its performance. He said it flew nice, just slow so he ripped the power system out and into another plane and shelved the airframe.
I bought it off him and decided to turn it into a pusher project Now the whole objective of this project was to make it still fly like an EDF(i.e fast) but try and keep the cost, weight etc down and be able to use relatively cheapish batteries.
I experimented with working canards but couldn't get the play out of them while the plane was airbourne, they always wanted to push the nose down so in the end I just ended up making them fixed.
The motor had to be mounted above the exhaust take for prop ground clearance but if you were to bungie launch then you could mount it inside. I also decided I was going to keep the ordinance because of the cool factor so therefore had to run landing gear. After a few flights with the stock gear (crap ) I ended up putting mechanical retracts on, looks better in the air and a little less drag

This thing flies great now, as quick as an EDF but at half the amps! I use a 2650 4S 20C battery, get around 5min flights and AUW is 2.2kg.: with a little under 1:1 thrust ratio, I fly her mainly at around 70% throttle.

I use the following system:

Turnigy 3639 1100kv motor
Hobbyking SS 50Amp ESC
Turnigy 5A UBEC
Master Airscrew 10x6 prop

I can't test exact power figures at the moment but from memory it was over 500Watts for around 40Amps. I will up the prop soon to a MAS 10x8 and post exact power figures.
Posted by jbc | Jul 27, 2010 @ 08:57 AM | 17,352 Views

Keep them Lipos warm

Interesting test just performed here at JBCWorx which can be related to any of your planes. I just put my SU-27 onto the wattmeter with new Rhino 2x1750 3S 25C batts in parallel(should be able to supply 87A) for 2x64mm GWS fans. The batts are sitting in my bedroom where ambient temp is probably around 15-18C and batts are sitting on the shelf. I ran her up and she spat out 61A 650W which dropped to around 42A ish and 440W over a short 5-8sec timeframe and wouldn't go any higher...what the!!!! I thought it shouldv'e been higher than that. So swapped a 2200 3S 30C(should be able to supply 66A)and basically got the same reading hmmmm

After a quick discussion with the R&D department head (my brother Ozzi Supercub ), we decided to warm up the Lipo's by putting them in front of the heater for a bit, a little unorthodox but it works . I then re-did the test and got 66A for 745W which held at around 62-63A and 680-690W once the pack settled, now that's what I expect

I guess even though we don't really get that cold weather here in OZ compared to some other countries, it's obviously enough to affect Lipo performance.

A battery is basically rated by how fast it can charge and discharge its power. When a Lipo is cold, its internal resistance goes up.....alot! so it therefore can't discharge as quickly and supply it's maximum rating for very long. Better quality batteries will perform better but will still be susceptible to cold conditions, just not as much as cheaper ones.

Just be careful on colder days that you'll probably get shorter flight times, being aware of this might just save you and expensive crash