DJI F550 Build

Good questions and I have also wondered myself so before answering I took some photos for you to see for yourself.

Actually the Graupners are slightly shorter. Below are a few photos with a Left Graupner and a Left DJI propeller for comparison.

I checked the balance with Golden Child's propeller balancer and the Graupners out-of-the-box are dead on. The DJIs are just slightly off, and it is not enough in my opinion to merit any tape or sanding.

I have nothing even remotely close to being able to measure their weight. By hand it feels that if one is heavier it would be the Graupners, but that it totally subjective.

The Graupners are also thicker where it counts: where the blade meets the hub. Besides being thicker that area has a different shape, more elliptical where the broken DJI propellers are all flatter.

"I have nothing even remotely close to being able to measure their weight.  By hand it feels that if one is heavier it would be the Graupners, but that it totally subjective"

Not as 'subjective' has you might think!

True the hand is incapable of measuring actual weight but as to the difference in weight the hand CAN be very accurate! You can test this yourself with a card Trick I know. I can tell the difference or predict which card is which out of two cards, say the Black King and teh Red Ace just by their difference in the weight of the INK they are printed with ... Don't believe me try it you might be surprised as I was the first time I discovered the trick ... The card with Black INK will be obviously heavier ... Given even the tiniest differences the hand can tell ...

The Graupner looks like it would produce less lift at the same RPM, but it also looks like it might make up for the smaller size with more pitch near the hub?

The Graupner propellers certainly have a unique geometry.  They do have more pitch close at the hub and then they get flatter towards the tip of the blade.

This video is pretty lame, it was incredibly windy. It was so windy even the Rogue Valley Flyer's trainer plane was being blown all over the place. I have the camera hard mounted to the DJI F550 and you can barely see any jello effect. I think the Graupner propellers make a positive difference for the video.

That looks really good, long flight time!

I was surprised at how little jello I had considering the way I mounted the camera.  Firstly the camera isn't very tight in that particular mount any more after a few crashes besides the mount being fixed directly to the frame.

There was still some battery left but it was the end of the training day and people were ready to leave. 

I shot this video today at the Riverside Park.

I have a question for those of you who have original DJI arms:  Do you think the threaded inserts are molded into the arm, or pressed in after molding?

GPS - They are "insert molded" meaning that they are inserted into the mold before injection.

...Tiger

What if you had one that was missing the threaded insert, do you think drilling the hole in the arm to accommodate the insert and gluing would hold it in place well enough?

Don't they have screws top and bottom? could you drill all the way through and have a bolt and nut?

Oh, I see, it is different than I thought......

Looks like a tough fix.....

The missing insert is one of the bottom two.  The bottom plate has the electrical connections.

John - I wouldn't screw with it.  You can't glue it for sure.  We're talking about a $4 arm.  I'd just replace it.  I think the 550 uses the same arm as the 450.  I have an extra kit you could borrow an arm from until one you order arrives.  What color do you need?

...Tiger

Thank you for the offer John.  It's a arm I got from UAV Products that was a manufacturing defect.  It has been replaced so it's not holding me up in any way.  I was just wondering if it could be repaired.  I kind of thought they looked like they were molded into the plastic.  This one has a small hole but no insert.  I have some inserts from a broken arm and they are larger than the hole in the arm missing the insert so I thought I might be able to drill it a little larger and glue a insert in there.

John - That's really interesting.  I've looked at mine and I'm sure I've even seen flash around the end of the insert.  But... If there is a hole in the arm, then maybe it is pressed in.  If it was insert molded like I first said, then the plastic would have filled the hole if the insert was missing.  If you can, take a picture of the insert so I can see what the outside of it looks like.  If it's pressed in, it would be done in something like an arbor press, because it would take a lot of pressure.  It would be a force fit for sure.  You would not want to drill the hole out for sure.  If you want to give me the arm and the insert Sunday, I'll take a look at it and maybe press it in for you.  I have good equipment for doing that.

...Tiger

Thank you John.  My camera wouldn't be able to photograph these inserts but I can say they have longitudinal grooves in them.  I will show them to you next time we meet.

Could there be a "stud" inside of the mold that the insert slides onto for alignment during the molding? Is the hole in the plastic the same size as the hole of one of the inserts?

I just looked at it again (i.e. with my glasses) and the hole looks closer to the inside diameter of the insert than the outside diameter so you may be right.