Ricks Rush 750 build thread

[dodgeboy]

Originally Posted by OverTemp

What about the couple reports of cracked radius arms? Was this corrected? Should those be sized to prevent the cracking?

I was one with broken a radius arm link. I did resize the new one I put on. The first one I didn't.

[dunkonu23]

I remember, Mike. It's just my opinion based on my experience with the A-Arms.


Scott

[codfish124]

One of mine also broke..... I'm thinking it was because the plastic was a little cold. I would make sure to warm the arm up a tad before installing it.... No problem since

[dodgeboy]

Originally Posted by dunkonu23

I remember, Mike. It's just my opinion based on my experience with the A-Arms.


Scott

Scott, in no way was i saying your advice was wrong in anyway, so i hope i didnt come across as i was. i was just sharing my experience with the radius arms.

[dunkonu23]

I know, Mike! It's no issue, bro! It's all good!

Scott

[rdlohr]

So, I installed my rudder servo and control rod last night. I got some nasty noise when I exercised the tail. The ball links seemed really tight so I put a ball in my variable speed drill and gave both links some mileage while I continually changed the angle of the ball. This quieted things down considerably but its still sounds a lot more gravelly than what I am used to.

Can't say I love the metal control rod over a CF rod. It bangs around noisily in the guides and was prone to bending when I didn't have the guides strategically placed during checkout.

Rick

[dunkonu23]

Rick,

The noise is normal. We believe it to be resonance. All of us have it. It hurts nothing. As far as the guides go... I let them find their natural place. I line them up, spaced evenly, the exercise the rudder vigorously. The center guides usually settle in to a good spot pretty quickly. Once they settle, I tighten them down. Next, I repeat the same thing for the outer guides. It works out pretty good.

Scott

[rdlohr]

Originally Posted by dunkonu23

Rick,

The noise is normal. We believe it to be resonance. All of us have it. It hurts nothing. As far as the guides go... I let them find their natural place. I line them up, spaced evenly, the exercise the rudder vigorously. The center guides usually settle in to a good spot pretty quickly. Once they settle, I tighten them down. Next, I repeat the same thing for the outer guides. It works out pretty good.

Scott

OK thanks, I'll use that approach to line them up. A little CA on the threads when done I assume.

I'm not sure I understand the "resonance" idea. Could you elaborate on that a bit?

Rick

[dunkonu23]

CA on the threads if you wish. I didn't do it.

Resonance... well, that's what we're calling the noise. The frame/boom appears to be amplifying a set of frequencies that the tail servo makes. It only makes the noise when the tail servo is driven. Move it by hand and there's no noise. I didn't use servo rubbers on my tail servo, but I've had the noise with tail servos of similar specs. We don't know this for sure, though. I don't have the equipment to validate that anymore, so it's really an educated guess.

Scott

[rdlohr]

Originally Posted by dunkonu23

CA on the threads if you wish. I didn't do it.

Resonance... well, that's what we're calling the noise. The frame/boom appears to be amplifying a set of frequencies that the tail servo makes. It only makes the noise when the tail servo is driven. Move it by hand and there's no noise. I didn't use servo rubbers on my tail servo, but I've had the noise with tail servos of similar specs. We don't know this for sure, though. I don't have the equipment to validate that anymore, so it's really an educated guess.

Scott

Interesting, thanks. I do have the rubbers on my tail servo and it still does it. I'll have to use my hand on the boom to try to dampen it just to see what happens.
Rick

[rdlohr]

Originally Posted by rdlohr

Interesting, thanks. I do have the rubbers on my tail servo and it still does it. I'll have to use my hand on the boom to try to dampen it just to see what happens.
Rick

That's truly strange. The gravelly noise originates in the servo then it gets amplified and broadcast by the control rod and the tail. Nothing I could do with my hand dampened it.

Rick

[dunkonu23]

I was going to use the boom and the tail control rod as an iPhone amplifier so I could hear my tunes in the pits... Seriously, it's just the way it works. I can't explain why, either. Maybe it's just something in the resonant frequency of the helicopter.

Scott

[rdlohr]

Originally Posted by dunkonu23

I was going to use the boom and the tail control rod as an iPhone amplifier so I could hear my tunes in the pits... Seriously, it's just the way it works. I can't explain why, either. Maybe it's just something in the resonant frequency of the helicopter.

Scott

lol!
I think the metal control rod rings/resonates. I bet a CF rod may dampen it. The fact that its such a big heli/long rod increases the affect. Have you seen this on other large helis? Did they have a CF control rod or metal?

Rick

[rdlohr]

Did battery straps come with the kit?
Rick

[saeed09]

Originally Posted by rdlohr

Did you do size your links?

By the way, or ordered 3 of the horns you told me about, and 4 batteries at ReadyHeli. Still not sure what horn I will use on the Futab BLS251.

Rick

If i didnt mix up my memory, I remember am using Align crossed servo horns on all my futaba, 251 and 256. They work just fine.

Saeed.

[rdlohr]

Originally Posted by saeed09

If i didnt mix up my memory, I remember am using Align crossed servo horns on all my futaba, 251 and 256. They work just fine.

Saeed.

Thanks Saeed. I just used a horn that came with the 251. It seems fine.
Rick

[saeed09]

Originally Posted by rdlohr

Thanks Saeed. I just used a horn that came with the 251. It seems fine.
Rick

Rick, I remember i dont use orignal ones for a reason. I have to check. I think they are alittle short. Need to recheck.

Saeed.

[dunkonu23]

Originally Posted by rdlohr

lol!
I think the metal control rod rings/resonates. I bet a CF rod may dampen it. The fact that its such a big heli/long rod increases the affect. Have you seen this on other large helis? Did they have a CF control rod or metal?

Rick

No, I haven't seen this on my other 700 sized helicopter. It does have a carbon-covered metal rod, though. The Rush rod doesn't cause any problems, though. It's just noisy up close. In the air, you can't hear it.

Scott

[dunkonu23]

Originally Posted by rdlohr

Did battery straps come with the kit?
Rick

No. I use four Scorpion 12" straps--not in the slots, but between the battery trays. Some people use a fifth strap across both packs positioned between the other straps.

Scott

[rdlohr]

Originally Posted by saeed09

Rick, I remember i dont use orignal ones for a reason. I have to check. I think they are alittle short. Need to recheck.

Saeed.

OK, thanks. I am on the third hole and I get just a tad less than full range so I was planning on moving to the fourth hole during tuning. It is plastic so I'm not in love with using a hole so far out. I would consider another option that was sturdier.

Originally Posted by dunkonu23

No, I haven't seen this on my other 700 sized helicopter. It does have a carbon-covered metal rod, though. The Rush rod doesn't cause any problems, though. It's just noisy up close. In the air, you can't hear it.

Scott

OK, thanks.

Originally Posted by dunkonu23

No. I use four Scorpion 12" straps--not in the slots, but between the battery trays. Some people use a fifth strap across both packs positioned between the other straps.

Scott

Rats, I wanted nice Alees straps! Charley!!

Does RH have the straps you use?

Rick