RPM (thrust) Test --- PART 4

We take this Tin Goose Rebuild to the testbench. Equiped with the 1700kv brushless motor a 8x4.5 folding prop and the 2cell 7.4v 800mAh lipo battery. This setup produces 7200rpm. This will result in 290 grams of thrust. Total weight is only 350 grams. This is a great result, but you have to keep in mind that the maximum flying speed with 8x4.5@7200 will be slower than 4.3x3@12000 rpm.

RPM (thrust) Test --- PART 3

There is one test left to run on the original setup. Replacing the battery with a 3 Cell lipo. I currently have no small 3cell lipo that fits in to the original battery holder. Small 3Cell 11.v 800mah batteries exist and they have the same weigth as my nimh battery and would fit in to the original battery holder.

In the movie you see I use a large 3cell lipo. The result of 19000rpm is enormous. This will produce 170 gram of thrust per motor. When I would use a small 800mah 3cell lipo the result may be different. But you can be shure that you will get at least 16000rpm resulting in 120 gram of thrust per motor. With a 3cell lipo you will get a ratio around 1:1. With this amount of power you can fly it as an acro plane.

The only problem with a 3cell lipo is that these motors are not made for this voltage (wattage). So flying full throttle for a long time can overheat and damge the motors. So only try this at your own risk :)

RPM (thrust) Test --- PART 2

The next test is obvious. Replace the Nimh battery with a Lipo battery. We all know that Lipo batterys are more powerfull and weigth less. I replaced the "7.2v nimh 700mah battery" with a "2Cell 7.4v lipo 800mah battery". This type of replacement will fit nicely in to the original battery holder. This will also result in a total aircraft weigt of 420 gram (30grams less).

As you can see in the movie I got 12000rpm with this 2cell lipo battery charged up to 7.58v. Thats a good result so far. This will produce 60grams of thrust per motor. Giving me 180grams of tot thrust. And that should be enough to fly this plane as a trainer in no or low wind conditions.

But we would like to have even more power. Just to fly it like a sportsplane or just to add more weigth like an onboard camera or an autopilot board. Testing continues.