550sx tail belt problems?

[el guapo]

Originally Posted by trippergreenfeet

How many of you guys having this tail belt/pulley issue (with stock part) are running maxed out deflection on the tail blades?
.

I used to run max deflection.... but my logo used to fail a lot... I snapped a belt and exploded two tail grips. very expensive. I almost gave up on on logos. but since limiting tail pitch, every thing has been solid.

[maarset]

Originally Posted by el guapo

I used to run max deflection.... but my logo used to fail a lot... I snapped a belt and exploded two tail grips. very expensive. I almost gave up on on logos. but since limiting tail pitch, every thing has been solid.

So you still run max deflection, but limit the tail travel? What is this max deflection?

My logo 500 has the CF tail box and the idler pulley is just in front of the tail pulley. Stock 500SE idle bearing doesn't work for me. If I go super fast backwards and then jerk the tail back and forward the belt would slip off.

Now I still have the 20mm boom but I have the raptor 30 belt and two larger idle bearings that almost enter the tail pulley. So far it works great. I can run the raptor belt tighter and it still turns very smooth.

Mike


Sent from my iPhone using Tapatalk

[trickybit]

I followed the advice to not allow full-travel on the tail, so it would not "stall."

Then I was having some tail-hold issues, and Jesse Kavros took a look and put back in full travel and the tail worked better.

On that heli (600 w/ SX tail) I have a fat bearing, so I can't speak to any issues w/ belt jumping.

[el guapo]

Originally Posted by trickybit

I followed the advice to not allow full-travel on the tail, so it would not "stall."

Then I was having some tail-hold issues, and Jesse Kavros took a look and put back in full travel and the tail worked better.

On that heli (600 w/ SX tail) I have a fat bearing, so I can't speak to any issues w/ belt jumping.

physics is the law.

https://www.helifreak.com/showpost.p...12&postcount=1

[trickybit]

Diagram and thread show that stall bad for efficiency. At some point thrust stops increasing, but what tells us where a Logo pitch slider limit will reach the point of fully-diminished marginal effect?

For example, in the cited post, the "vertical grey line in each window defines the rotor stall onset" but there's considerable more thrust to be realized past that point of diminishing return.

As for the marginal current draw, I assume the tail effect on current draw is peanuts compared to the big boys.

[hemp]

Originally Posted by el guapo

physics is the law.

The laws of physics, sure - but the application of them is imperfect, which is why engineers start with calculations that are then tested and corrected through real-world application. Otherwise we wouldn't need the scientific method, "the math works so it must be true."

[el guapo]

Originally Posted by trickybit

At some point thrust stops increasing, but what tells us where a Logo pitch slider limit will reach the point of fully-diminished marginal effect?
.

that point in his data was 30 degrees of tail pitch. 30 degree was where thrust stopped increasing. then after 40 degrees, thrust vs pitch slope is negative. soooo... over thirty offers no benefit and over 40 is useless. these are the boundaries.


given that we are talking about the max mechanical tail pitch of a logo600.... the conversation might be more effective if we agreed on what that number is.....45 degrees is easy to measure... just fold the tail blades and form a 90 degree angle between the blades. that is 45. the logo600 has more then 45. probably around 55degrees. which is completely outside the boundaries.

[el guapo]

Originally Posted by hemp

The laws of physics, sure - but the application of them is imperfect, which is why engineers start with calculations that are then tested and corrected through real-world application. Otherwise we wouldn't need the scientific method, "the math works so it must be true."

engineers start with intuition.

[DannyvG]

for 3D performance you need all the tail pitch you can set.
See the 2 last replies in the topic mentioned earlier
https://www.helifreak.com/showthread...34#post5181534

Limiting the tail pitch will really reduce the performance.

[el guapo]

Originally Posted by DannyvG

for 3D performance you need all the tail pitch you can set.
See the 2 last replies in the topic mentioned earlier
https://www.helifreak.com/showthread...34#post5181534

Limiting the tail pitch will really reduce the performance.

if you take statements out of context, then sure... but 45 degrees was presented as extreme in the last post. I set mine to 45 degrees. thus already extreme....full travel on the logo is well beyond that.

if it allowed 95 degrees, would you use that?

most helis are not even close to 45. most helis you can set full ptich... for example my TDR won't even allow 45 degrees, thus use all of it.

[DannyvG]

I was under the impression you suggested to limit the pitch to 30 degrees or perhaps 40 degrees.
I just sold my last logo so I cant check how much pitch it really is but we set the slider completely against the hub.

[el guapo]

this is my last visit to this thread.

this is full mechanical travel on one of my logo600s. i do not use full mechanical travel anymore.

[totonor]

Hello ,

The answer of mikado about the pitch of tail blades :

the tail blades should have a max. pitch of about 30°. So Your setup is perfect.
More is not useful because there is no more increase of thrust

So it's 15° per blade ?

Regards

[trickybit]

Originally Posted by totonor

Hello ,

The answer of mikado about the pitch of tail blades :

the tail blades should have a max. pitch of about 30°. So Your setup is perfect.
More is not useful because there is no more increase of thrust

So it's 15° per blade ?

Regards

generally, pitch is per blade, not considered as being in the folded configuration.

[totonor]

You're right , it's 30° per blade.

[DannyvG]

Just remember that with only 30degrees pitch you can get tail blowouts in funnels and such manouvres that demand a lot of tail pitch/thrust.
But when you are only sport flying it could make tuning a bit easier and it stresses the servos and mechanics less.

[totonor]

Hello danny ,

Mikado says :
More is not useful because there is no more increase of thrust

So , if there's no more increase of thrust , i should have no problem , isn't it ?

Regards

[DannyvG]

Then mikado seems to be wrong with that statement.
They perhaps dont know the difference between angle of attack and angle of incidince
Check the topic that was mentioned before https://www.helifreak.com/showthread...34#post5181534

[maarset]

https://www.helifreak.com/showpost.p...4&postcount=11

[nivaldin]

Originally Posted by francis234

I having the same problem. I readjust the tension . Problem solve

Hi Francis, your tension was too tight or too loose?