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Helis and fixed wing

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Thursday, September 1, 2016

Slipstream Extra 540 1000 mm 450 size

(Gary Hoffman pointed out to me this is a Extra, not an Edge).

A few weeks ago I bought a Slipstream Extra 540 450 size (you won't find a link, I think they don't make it anymore), an Eflite 450 motor and a Castle 35A ESC from my friend Gary Hoffman. It was lived in by a chipmunk, both other than that was new and unbuilt. I bought it as I was looking for a light weight plane to toss around (when I got my Hobbyking Edge). I can't program the ESC (tried using both my Castle program card, and my Hobbywing program card.

I finally ordered the servos (see my last post), and set about putting this thing together. It came with the Chinglish instructions on CD which weren't very helpful. Its a nice plane, but its very light and I think not long for this world for being so fragile.

The only annoying thing about this plane is the motor box. Its designed such that the firewall is immediately at the end of the cowl. Its not the easiest design to work with as it requires the shaft pass through the firewall so it needs to be longer, usually requiring replacing the shaft with a longer one if its not designed to fit this way. The Eflite motor isn't, so its shaft is too short. I tried changing it to a longer one, but it would not run, and on replacing the shaft I found it wound not run. I did when I first set it up to test the Castle ESC and the motor, so I have somehow bricked it. I have changed a lot of shafts from my early flying days, and with the original shaft the motor manually turns clean, but it just sits and jitters like its out of sync... I looked, the inside of the outrunner has no metal parts stuck in there, the connections are good, and it doesn't matter what ESC I use. I also tried the motor on other ESCs.

I purchased an Emax GT2218/09 1100kv motor from HeadsUpRC, my go to electric motor guys. This is a powerful 450 sized motor, generating 300W on a 3S battery with about a 10x6 prop. This plane come in under 2 lbs AUW, so this will be very nicely powered. Its designed for both through the firewall and standard shafting, so it should do nicely. If there are any issues I will build a new engine mount.

I used the stock tailwheel, the gear of which is flimsy, so its going to need to fly off very good grass or the Geo-tex. I did replace the tiny stock wheels with slightly larger ones, so won't be using the wheel pants.

The geometry on the ailerons is off. If you put it straight-ish like I did here, the control horn, which presses in on two plastic pins and is not screwed in, it lies at the edge of the hard point on the aileron. You can see the wrinkling of the cote where the right pin on the horn is just in the wood.

I installed the other one stock, and its angled funny, but the pins for the horn are both in solid wood.

I have everything on board except the motor mount and the motor, which should be here in a day or two. Pretty plane!

I took the 3-axis stabilizer from the Cornell, which I rarely fly, and put it in the Edge. I programmed it and its all set. One precess is to turn the gain up on each of the three axes one at a time to magnify its behavior so you can see that it responds opposite to the "unstable" movement. For example, if you roll the plane right the ailerons should move to roll it back left. There are small switches on the gyro that you move to change the direction, easily, then turn the gains down to barely move. If they are too high you'll get a lot of oscillation as airflow alone causes subtle changes in pitch, yaw and roll, most notable during a dive.

I like these 3-axis systems from Hobbyking which incorporate a Spektrum compatible receiver. For some reason they are NIS at their warehouses, so I need to wait to buy replacements.

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