Belt 6HV FBL conversion

[sutty]

Just kidding. Enjoy.

Cheers

Sutty

[jperkosk]

OK, the saga continues... There was not much trouble repairing the boom supports:



Comparison with a boom of Blade SR after the blade strike, that one was bent beyond repair some time ago:



Better than new?:



The problem was that I needed to raise the head by 5mm, so I needed to extend Delrin arms. That, while doable, turned to be more involved than I thought, had to take them completely apart to make sure the plastic eyelet had 10 turns in on each link and put a bit of locktite on the thread going into the Delrin arm's body.

So the test flight happened yesterday:

[ame]http://www.youtube.com/watch?v=SCHxzam2Y7w[/ame]

Andy, I set-up a bailout SL and actually tested it @ 1:55, kind of works . Having a setup problem with a governor, so it needs a bit of work, I had head's RPM all over the place which causes vibration and disables all of the sudden SL on SK720.

For comparison, a similar bailout test on the 2nd TR600N, CP2 setup identically as the other one and yours, both gains @40%. The test is at 0:40, later I tried to repeat it but the wind had picked up and I was too chicken to really lean it >20° so the ER wasn't kicking in properly when flipping CP2 on:

[ame]http://www.youtube.com/watch?v=Buf-Ze8Cj7w[/ame]

[ragge1]

Originally Posted by jperkosk

The problem was that I needed to raise the head by 5mm, so I needed to extend Delrin arms. That, while doable, turned to be more involved than I thought, had to take them completely apart to make sure the plastic eyelet had 10 turns in on each link and put a bit of locktite on the thread going into the Delrin arm's body.

thats good it worked , but don't get it I didn't have raise my head ahhh I think its the endless blue sky over there

[jperkosk]

1900m altitude equals 80% of atmospheric pressure, this might be playing into resonant frequency equation, and once you there, you saw the video !!!

Ragge, have you seen anywhere in stock simple things like boom supports, landing gear and Delrin arms? This time even 711rc seems to be out of stock...

[sutty]

That was good Jerry. I enjoyed the demonstration, and it was pretty windy too. You might have sunny weather fairly often, but you seem to have to put up with some fairly heafty winds for a lot of the time. Mine doesn't do that, it does nothing, but I wrote about that in my MB/CPII thread. I know I'm doing something wrong, but what, I don't know. On one trial I tilted it a lot more than you did, close to 45 degrees on one test, flicked the switch, and no change. All will become clear when I look at it on Sunday. Tomorrow would be good, but I can't test it in the air then because tonight I have been drinking. Might review the settings on the ground though.

Cheers


Sutty

[ragge1]

Originally Posted by jperkosk

1900m altitude equals 80% of atmospheric pressure, this might be playing into resonant frequency equation, and once you there, you saw the video !!!

Ragge, have you seen anywhere in stock simple things like boom supports, landing gear and Delrin arms? This time even 711rc seems to be out of stock...

Nankin got most of parts and he's starting to sell out of US too
some few links
http://www.nankinhobby.com/helicopters/cat_2.html

http://www.experiencerc.com/store/co...sort=1a&page=1

http://rchelicanada.com/compass-heli...rts/cat_5.html

[jperkosk]

Managed to sneak out for another couple of packs last evening, actually it was 90% overcast (an aberration that will probably be remedied today ) but almost no wind, hasn't been this calm in ages !!!

In the calm weather I found out I still had some tail issues, had to drop the gain quite a bit, after that it was all very decent:

[ame]http://www.youtube.com/watch?v=mC94H7OKMHI[/ame]

Tested a bailout with SL set to 100% and it sort of works, but not very reliably. Sometimes it levels half decently, other times with a very strong list to one side or another. Analyzed vibrations (SK720 has an excellent vibration analyzer), and there are strong vibrations coming from the tail. Checked it and yes, tail shaft bearing is on the way out ; another item on my Compass shopping list, probably will order the whole tail if I can find it.

6HV's biggest problem so far is a typical Esky spotty parts availability

Also properly tested HW-70A-HV governor, video above is done with 2000RPM set in HW; it's passable but not excellent. Will test today SK720 governor and compare them.

[sutty]

Repair looks good Jerry. Enjoyed the video and the commentary, complete with ooos and aaaas, lol. Sounded like you were having a good time. Also no trace of the spool down vibration issue, although I noticed you landed on the grass, which in the thread you linked, I read that it is less apparent on grass, so maybe that contributed? Have you tried a spool down on the tarmac as well since the modification? Also noticed no folding of the blades on spool up so I guess you have them tighter now as well.

Wish I didn't feel so rough today, as it is absolutely perfect out there. It would be a great day to do another trial of the CPII. Still I had a great time last night, so I guess it was worth it. Sunday might well be the same weather, so hopefully will have a double check of the settings this evening, and give it another go tomorrow.

Cheers

Sutty

[jperkosk]

Have you noticed that we can still drink the same way as 20 years ago, we just take 4 times longer to recover?

Yeah, in this video I landed on grass but I have already spooled down a dozen of times on tarmac, no problem since I raised the head 5mm. Not just a reduced vibs or anything like that, the spool-down resonance is completely gone, banished. Amazing.

And yes, I tightened the blades considerably. Not to the point of having to apply a knee to fold them , but I do have to apply some force with my hands now, about half way between what I had before and what Grant has, I guess

[Tomstoy2]

Jerry, as you well know, got to get the vibes down.

Once you do the sl feature will be amazing! The trick is to get the vibs to stay low when you are hammering about in the sky, rapid pitch changes, hard stops and such.

Takes time, and you are doing the right thing, baby steps to get there.

Once you are satisfied, flip her inverted and turn on the sl. It works like a charm.

Very interrested to read how you get on with the sk and the 6hv. So many posts from people dealing with this, possibly more than any other heli posting I've seen!

Looked real good, though!

[jperkosk]

OK, I think I'm ready to finish the story.

Today I have finished the governor tests.

Spooling up with HW-70A-HV governor set to high, 76% flat throttle curve in the Tx, SK720 gov disabled:



Spooling up with SK720 governor set to 2000RPM on the first setting, 40% flat throttle curve in the Tx, HW-70A-HV gov disabled:



SK720 governor rocks !!!

The last flight in a while, because I'm really having a problem with the tail bearing and I'm afraid it'll blow out on me... I'm having continuing problems with the tail wag, and the bearing sounds worse and worse, you can hear it in the video, so she's grounded until I get the tail fixed:

[ame]http://www.youtube.com/watch?v=UGypCNH4EWI[/ame]

[jperkosk]

Sorry, uploaded wrong video to YT. Here is the last flight from yesterday before grounding her, you can clearly see the tail getting worse and there is this bad bearing sound audible when I hover her close to the camera...

[ame]http://www.youtube.com/watch?v=TEC74l3OUMo[/ame]

[sutty]

Don't know about when it is close Jerry, I could hear it nearly all the time, lol. You have done right to ground her. Hope you can easily find the appropriate spares.

Amazing that the spool down vibes have gone completely with the head position mod. Such a small change and such a big difference.

Cheers

Sutty

[jperkosk]

A photo from last Saturday: a family car vs sports car



BTW, how do you like my new Tx tray?

[sutty]

I was just about to ask you about that, and then you asked us. I don't know, but I am ever so interested to hear what you think about it.

Cheers

Sutty

[DominicD]

A Tx tray and a dx8 !! You are so banned for life

[jperkosk]

Have a mixed feeling about this tray; assembled it a week ago and been testing it since.
Helps to keep Tx steady, no question about that, much smaller chance of a finger slipping. I'm a pincher, and it feels really comfortable.

The drawback is it takes an extra time at the field: I need to mount DX8 in it and don the harness, not that much of a PITA, but still takes 1-2 min.

It's probably worth it to keep using it, but the difference is not as dramatic as I was expecting; in fact it's rather small.

[jperkosk]

After long time I have finally changed the tail bearings last Friday, loaded the newes Skookum firmware (v3.15) and flew around 3 packs on Saturday. Really had my hopes high up that it would be the end of the saga and I could finally declare her completely airworthy, but it was not to be . Enclosing a video from the third flight below.

1. The vibes are about the same as my logs from January show, maybe a bit lower now. The dry metallic bearing sound went out for the most part, but not really sure if it isn't coming back every now and then
2. The tail is still giving me a problem, can't calm it down no matter the gain . Beggining to think I may have to redo the whole SK720 setup, and if it doesn't help, change the mounting again.
3. Bailout feature works marvelously! Somewhat slower than CP2 (which isn't dialed very aggressively on my other machines) but still impressive. The bailout test @ 0:56.
4. Another problem appeared on pack #2: the motor stopped for 1-2 seconds twice midair . I wrote it off to the tired packs (this is the oldest and overheating set), but then it happened again on set #3 which is almost new, @1:40, so I landed her. Looked at the telemetry and SK720 RPM data and saw some noise from RPM sensor (Spektrum), this could very well be the reason since I'm running SK720 governor. Will get a ferrite ring to filter the noise, may also have to re-route the sensor wiring.

[ame]http://www.youtube.com/watch?v=RwjQxd5EdmU[/ame]

[jperkosk]

Installed 2 ferrite rings on the Spektrum RPM sensor, one on the input and another on output wires. Telemetry still reports RPM noise with no load, but under the load things seem to have improved. It's not conclusive yet, only tested with one battery pack. Ordered 2 Eagle Tree sensors from HK just in case. Can't stabilize the tail, there is a wag there no matter what I do . Dry bearing sound keeps reappearing, suspect timing belt guides now, but no spares in my 6HV box . This is becoming a second Denis' "600N rebuild" thread .

[ame]http://www.youtube.com/watch?v=sOrP05aPBkM[/ame]

[Jeff_Barrett]

Try this... turn off your SOFT START on the ESC and test. Let me know if that fixes the tail wag issue.