Compass 550U Build

[cyclo]

Forgot to mention that I have my pitch set to +-13 degrees. I will be setting it back down to +-12 degrees and upping the HS to 2350 just like FlyBri.

Was going to test the 550U with the updated settings and the new lipos today but the outside temps dropped again and it is too windy.

[Rdavis007]

Beginning a rebuild, and want to disassemble the OWB as you have. A question I have is did you repack the OWB with silicone grease or is this necessary before reassembly?
Thanks

Originally Posted by cyclo

I will leave it as is with the tiny bit of slop (less than an mm from the looks of it). The delrin main gear is indeed beefy just like the ones on the 7HVU and Chronos... Never had a problem with those too. Haven't had the need to replace them even after a crash.

I decided to go ahead and use ATF on the OWB. To do this I disassembled the main gear / belt pulley and removed the hub. I then soaked the hub in isopropyl alcohol and also used a nylon tipped swab to scrub the insides of the OWB clear of factory grease:



I am currently soaking the OWB and the sleeve in ATF as pictured below. Will let the part sit in ATF while I now get started with the build proper... Step 1 appears to be the head assembly from perusing the manual.



EDIT: To ensure ATF gets inside the housing of the needle bearings in the OWB I also repeated the following process a couple of times: Insert the ATF soaked sleeve inside the ATF soaked OWB and rotate it a few times. Remove the sleeve, soak both sleeve and OWB in ATF and repeat.

[cyclo]

Originally Posted by Rdavis007

Beginning a rebuild, and want to disassemble the OWB as you have. A question I have is did you repack the OWB with silicone grease or is this necessary before reassembly?
Thanks

I removed the factory grease by dipping the OWB assembly in isopropyl alcohol and also using a nylon tipped swab dipped in isopropyl. I then dip the OWB assembly and sleeve in ATF, let it sit for a couple of minutes before assembly.

This procedure (removing factory grease and lubing with ATF) is optional but I have done it when building/re-building all my Compass helis (Atom -> Chronos). The X3 OWB is too delicate to perform this operation successfully. ATF for OWB has also been recommended in this recent thread on the main forums.

[PassinThru]

Originally Posted by cbest

Sorry to hear you guys putting them in. My 6hvu is the largerst heli I've ever owned or flown, & I've only done so a few times. Just recently got her in the air. It flies great, it really does. Awesome. I've crashed my smaller helis literally a thousand times, but I just can't stopping thinking about how I would feel putting something this big (& beautiful) in. I guess if it were my beater I wouldn't mind so much, but it's not. Had it all charged up the other day ready to fly. Started thinking about crashing her, next thing I know I was putting my batteries on storage charge & putting her back on the shelf.....

NOOOoooooohhhhh!!

[cyclo]

I had a couple of 3S 3300mah 35C lipos lying around not being used as I haven't flown my FPV quad in a long time. I decided to build a deans to EC5 adapter / parallel harness so I can use two of them at a time to power the 550U for low head speed flying.

With the two 3S lipos the 550U was a bit tail heavy but flew very well nonetheless. I estimate the head speed with the 3S lipos to be around 1400-1500 rpm. It piros extremely well despite the cg being biased to the rear. The tail also held very well... I was doing slow motion punch outs, rainbows, aileron tic tocs, and funnels and the tail was locked in.

EDIT: I was getting 6 - 7 minute low head speed flights on 2 x 3300 mah lipos.

Pic showing the 3S parallel harness / deans to EC5 adapter... I positioned the lipos as far forward as possible but the cg was still biased towards the rear... No problems in flight though:


Size comparison between Pulse 6S 5000 mah 65C and 2 x 3S 3300 35C lipos:

[dominator]

Nice! I love flying low head speed. The sound the blades make is awesome

[cyclo]

Yes the lower the head speed the nicer it sounds. I am also thinking the lower combined weight of the 3S lipos (compared to 6S) might make the 550U auto better.

[cyclo]

I finally found the time to upgrade the Savox cyclic servos to MKS on the 550U. The Savox were getting hot flying during the summer plus I also can't fully tune out porpoising on full collective loops. I got these on sale at Amain when they had their Black Friday sale last year.

[Hobee]

Cyclo, what a great thread! Thanks a lot for taking the time for all the detailed posts.

And then those great pictures! I can't wait to start working on my new used 6HV-U, taking it all apart and reassembling it! And going through this thread made my anticipation even bigger! I'll certainly review each step here a couple of times during the (re-)build.

[cyclo]

Originally Posted by Hobee

Cyclo, what a great thread! Thanks a lot for taking the time for all the detailed posts.

And then those great pictures! I can't wait to start working on my new used 6HV-U, taking it all apart and reassembling it! And going through this thread made my anticipation even bigger! I'll certainly review each step here a couple of times during the (re-)build.

Thanks Hobee... I'm glad you like the thread. Congrats on your 6HVU I am sure you will like it. My 550U is still going strong and has become the primary workhorse heli of my fleet after the demise of my Atom 500. It flies real well, is tough and reliable.

Below is a pic I took last Sunday... 550U with the Chronos and X3. I always take the 550U with me.