Chronos Blade Grip Arm Part Number

[Rob43]

I'd never have imagined this failure scenario. It already seems to be so robust. It must be pretty close to good enough as it was originally to not fail, or I'd think we'd have seen it more frequently with anyone flying hard with any of the 300+ oz-in servos in use today. One thing I thought of which could increase the loads would be bent pivot bolts which attach the arm to the Compass pitch change links. I've not found mine to be bent at any time I've had them out. As I had also replaced my steel bolts with stainless steel, I think I will replace them back to originals to be safe. I am sure they are stronger than the stainless bolts I've substituted.

[rc18]

New stuff arrived today, going to install tonight. The old arm's walls were around 2mm thick while the new one's is 3mm thick. When viewed side by side the new arms look super beefy.

[RedJoE]

In any event, looking at what I'm seeing, I would highly recommend everyone to carefully inspect their arms. At first glance, I saw nothing wrong with the arms, it wasn't until I started looking under a magnifying glass and started to see the cracks forming. Very difficult to see. From the outside you can make them out by very faint thin lines, almost looks like just a scratch and if you look at the side view you will see the cracks forming through.

[acidla]

The new arms look super beefy indeed! Lets hope no more cracking.

[renaudrenaud]

It's just petty they don't do this reinforced arm for the v1 Blade Grip..

[rc18]

Assembly of new blade grips, arms, spindle, and thrust bearings was easy and without any issues. Ready to test fly.

[renaudrenaud]

super
Wait for you feeling in fly.

[rc18]

Test flew the new blade grips and arms. In my opinion the heli flew the same and the flights were without any issues. So if you are worried about the arms the upgrade will give you piece of mind. Now with the extra thrust bearing I will crank down on the dampeners a bit more.

[RedJoE]

Got a hold of another used Chronos head, v1. Checked the arms, both arms have cracks starting through them. I'm starting to believe this problem effects almost all the arms out there. I recommend carefully inspecting them under magnifying glass.

Usually when this type of thing happens, the manufacture will issue a recall or even a replacement part if there really good. I think the best resolution would have been to offer updated replacement arms that fit the v1 head.

[Ah Clem]

RedJoE,

I have been flying a Chronos since they were first available and have quite a bit of time on it-sorry, no cracks in the arms.

This is usually a function of the end user over-tightening the arms or not aligning them properly on the single spline.

The new head includes more than just the beefier arms-the new grips have additional thrust bearings.

[Lighty]

I have to agree with yoda here.
15 Chronos models and no cracks. Most of these guys are very abusive with their flight. It needs the slightest nip, that's it.

[crf69]

i fly kinda hard.

no issues here with v1 and i have two chronos

[RedJoE]

Well, it's good to hear that others are not seeing the cracking like I am. Unfortunately since I got both my units used I was not able to verify the installations myself. I also agree that tightening too tight could be the problem here, however I'm not positive that is the case because the recent used head/heli I received was from a Compass team pilot and only had 25 flights on it. I truly did not expect to see any cracks in the arms, but when I tore it down to perform the chamfer modification to the arms, after carefully viewing under magnifying glass, I can see the cracks forming. The arm fasteners didn't appear to be very tight, but it's hard to tell since loctite is involved.

I would say that unless you carefully inspect the arms under a magnifying glass(preferably removed from the head while inspecting), it would be inaccurate to claim the arms are not cracking. You simply can't see the cracks unless you look very carefully with lots of light and a mag glass.

I would like to just purchase the v1 replacement arms and make sure the install is correct, however I'm being cautious. I see no need to go to the upgraded head, unless that's the only way to obtain an arm that doesn't crack.

[crf69]

i looked at my arms very closely today......i do have what looks to be cracks but upon further examiniation with more ligting i found these lines to be machining marks. i have two chronos and a complete spare head kit new in box and all three have these machining marks. which could be confused with cracks.

[RedJoE]

I managed to snap a few pics of these ones. 25 flights on these.

[cyclo]

I have checked mine before and mine had no problems... Over 100 flights since I Chronified my 7HVU and I don't take it easy... High speed full collective 360 loops, full collective punchouts, tic tocs. I like the adrenaline rush of full power and high speeds.

Below are pics I took this morning. I have the V2 head upgrade but have been lazy and/or busy with other stuff to install it.

[RedJoE]

So, are the pics I posted just casting marks?

[cyclo]

Originally Posted by RedJoE

So, are the pics I posted just casting marks?

Not saying they are but mine definitely have no cracks after more than 100 plus flights.

[Lighty]

Redjoe - Yours look like a crack.

[RedJoE]

Originally Posted by cyclo

Not saying they are but mine definitely have no cracks after more than 100 plus flights.

Did you do the chamfer modification before you installed them or at some point? Were you careful with the fastener torque during install?