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e-MS Composit Hornet > Flight popping.....??
 
 
Razmo
Key Veteran
Location: Chicago

Guys,

Finally getting the H2 in the air. Currently the head is entirely stock (I'm not even running an autorotation wheel, yet. I know, I know ) except for DeeTee's green rubber dampeners if you know them. They are a stiffer replacement to that of the stock black rubber rings. Still not stiff enough but should work.

Anyhow, I'm getting head pop. It's wants to inconsistently fall out of a hover and pop back. It can be severel inches to a foot or so.

Machine weighs 344 grams.

Thoughts?

Raz
10-23-2006 Over year old.
 
 
DarkHorse1
Senior Heliman
Location: Gloucester UK

Glitches from Rx, BEC or bad twitchy servo...

More likely CCPM and cyclic interactions. Due to a lazy servo's or poor servo geometry (see my tips page). The result is most noticeable when jabbing the cyclic, causes a brief rise or fall in overall rotor pitch (collective). Test by looking closely at the heli's head (spooled down, power on), hold the flybar horizontal and quickly jab and wiggle the cyclic to full extremes. If the flybar rises or falls causing a pitch change then that's a problem.

I stiffened up the stock damping O-rings by wrapping some thing tape around the hub (T shape) to thicken up the centre, then add the O-rings.
10-23-2006 Over year old.
HOMEPAGE  
 
 
jh4db536
Senior Heliman
Location: Monterey Park, California

i had that problem too. discovered that it only did that drop when i touched the cyclic, and then went back to normal when i let go. i guess this heli notices every little bit of load.

i got rid of it via programmable mixes...cyclic to throttle.
10-23-2006 Over year old.
 
 
Razmo
Key Veteran
Location: Chicago

It certainly isn't a glich of any kind. I think it's geometric setup as darkhorse mentions BUT I don't think it's cyclic interaction but I could be wrong. I did try my best to get all the servo links equally 90 degrees to the servo body but I may need to focus on getting all the servo links not only 90 degrees to the servo body but as vertical as possible. Double sided tabe is a bitch

I'll have to test for flybar movement tonight but I don't think I'm getting any. I did notice that I can pull up on AND push down on the collective horn thus creating my servo links to rotate a little changing blade pitch as well.

p.s. I haven't programed any mixes yet but I don't think it's related to cyclic stick movement.

Raz
10-23-2006 Over year old.
 
 
bobj
Veteran
Location: United Kingdom

Hi

Most likely it's your blades, if their the stock Hornet 2 carbon blades then these aren't weighted and lead a little in flight.
The blades for the X3D are the same but weighted and much smoother, either change the blades over for the new ones or dremel a slot in the leading edge and drop a couple of grams of lead in there.
If you do a search you will find a lot of info on weighting Hornet blades.

Cheers
Bob J
10-23-2006 Over year old.
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Razmo
Key Veteran
Location: Chicago

Thanks Bob, I am using E489 (weighted)

Raz
10-23-2006 Over year old.
 
 
DarkHorse1
Senior Heliman
Location: Gloucester UK

Well spotted. If your going to get new blades then you might prefer the flight characteristics of 257mm CF KOK composites. They seem smoother again and if you get them in with white covering they add some visibility to your rotor disk that the skinny MS CF's lack at high RPM. There are some more reports on here if you do a search.
10-23-2006 Over year old.
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MJWS
Key Veteran
Location: Airdrie, AB - Canada

Take a look at how much slop there is in collective. With the heli on if you gently twist the blades simulating adding collective is there lots of play? It is very hard to get things nice and rigid with double sided tape. I ended up CA'ing mine even though I didn't want to. CA'd the headblock ala 'Larson' as well. Helped mine out a lot.

You may be able to decrease your collective range a litte and or change up the pitch curve to soften it up a bit. A nice high headspeed and a little less pitch was the ticket on mine for nice smooth response.

Good luck. Every little thing on these makes a difference.

Mike
10-23-2006 Over year old.
 
 
Razmo
Key Veteran
Location: Chicago

Actually, I do plan to buy a set of the KOK's. Fortuntely, I bought a couple sets of Walts weighted blades awhile back. I just want to ge the feel for the stock blades first.

Raz
10-24-2006 Over year old.
 
 
Razmo
Key Veteran
Location: Chicago

I've just done what you suggested MJWS. I'm guessing I have 1.5 to 2mm of slop in collective. This must be my problem, some related to poor geometry, but with just little pressure, the servo plate seems to flex very easily.

Raz
10-24-2006 Over year old.
 
 
Razmo
Key Veteran
Location: Chicago

DarkHorse,

Is there any reason you chose not to list the ThunderPower 1320, 11.1 volt pack on your site? This is all I use. Each pack weighs 82 grams.

Raz
10-24-2006 Over year old.
 
 
DarkHorse1
Senior Heliman
Location: Gloucester UK

Yes 85g 3xTP1320mAh Prolite (tan stripe) 11.1v packs are listed on my site in my setup in the video section. Good choice for the Hornet.

> 1.5 to 2mm of slop in collective.
That's normal, as you notice the servo tray can flex so I glued thin plastic right angled triangle shapes under the tray to the frame (not essential). Also there is some stock swash plate slop. Don't worry about it too much and isn't that noticeable once the load take up the slop either side of the zero pitch point. Shouldn't be causing pitch popping/bobbing. You should see the slop in a HB-CP2 head and links (can suffer sticky blades grips), still fly's

CCPM/cyclic interaction normally related to servo speed divergence, precision and link geometry. Or sticky linkages, blade grips and pivot support block jamming. When the heli is on the ground at rest, put your finger on the top of the seesaw. Does your finger, the pivot support block and flybar assembly rise or full when you jab the cyclic on full and centre again? It should be rock solid, if it moves up or down then a pitch change will occur causing a problem.
10-24-2006 Over year old.
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Razmo
Key Veteran
Location: Chicago

Quote 
When the heli is on the ground at rest, put your finger on the top of the seesaw. Does your finger, the pivot support block and flybar assembly rise or full when you jab the cyclic on full and centre again? It should be rock solid, if it moves up or down then a pitch change will occur causing a problem.


Can you rephrase this? I'm not sure I understand what you're telling me here.

p.s. I don't recall seeing the 1320, 11.1v packs listed under the battery section of your ms-helituning.com website. They all look to be 7.4v.

Raz
10-24-2006 Over year old.
 
 
MJWS
Key Veteran
Location: Airdrie, AB - Canada

A mm or 2 isn't bad on these little guys. Btw, nice page darkhorse.

I don't know how interaction could cause it to pop up and down. Normally you just get a little bonus (say pitch when you add roll) with your input, not huge collective movement. Darkhorse's test is right on to check for this. I have seen bad curves do this, and very small glitches. Even had a gyro that would hit a little too hard and suck enough power to cause it to bob.

What motor, batts, servos, controller, headspeed, etc?

Good luck. Nice to see another one of these in the air.

Mike
10-24-2006 Over year old.
 
 
DarkHorse1
Senior Heliman
Location: Gloucester UK

Ah I see, thanks.

The www.ms-helituning.com site is a link I put on my pages as they have some useful build info and good clear images. They have added some info recently and the setup page is new. I hadn't seen their 'Lipos' page before and have no idea why they don't quote 11.1v. All I can assume is that the Lab test docs are for 7.4v.
An 11.1v 3 cell pack is what you want and Thunder Power are still the lightest best quality you can buy today for this application. Sorry about the confusion.

Back to the bobbing. It seems the high head speed light micro does bob on ground effect turbulence more than you would expect. Mine gargles in it's own down wash making a distinct noise and looses a bit of altitude occasionally. If you not touching the sticks then it could just be this may be.

> Can you rephrase this?
Try the bit marked 'Setup up CCPM geometry and symmetry' and accompanying thread link on my tips page.
You might find that what jh4db536 said, by adding some Programable Tx mixes reduces the effect:
Mix1 ch1->ch3 +/-20% aid rotor power loss on cyclic Aileron
Mix2 ch2->ch3 +/-20% aid rotor power loss on cyclic Elevator

Fire back with some more info and observations and we'll try and figure it out.
10-24-2006 Over year old.
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Zaneman007
Key Veteran
Location: Texas - USA

I would check the linkages. If one of the ball links is stripped inside, when you give is a little pitch it will slip. This causes a popping sound (due to sudden radical change in pitch) and the heli will jet up. I had this happen on a blade CP with a brushless motor. There was nothing noticeable on visual inspection. You have to pull on the links and see if they slip. Other than that no clue.
10-24-2006 Over year old.
 
 
Razmo
Key Veteran
Location: Chicago

Okay, I have some new information.....

I did exactly as DarkHorse said (I think ). When I apply fore, aft and either roll cyclic I can SEE the collect horn, seesaw bump up or down and even wobble like. I can also SEE the main blades changing.

I decided to dig deep into my box-o-goodies that I've collected over the years and came across a set of custom servo mounts that look very interesting.

I'll report the outcome when I have some time to piece it together. It will certianly take the frustrating guess work out of precise 90 degree angles and allows for no flexing.

Raz
10-25-2006 Over year old.
 
 
Razmo
Key Veteran
Location: Chicago

Guys,

I just came across something interesting. I have a new X3D kit that I haven't pieced together yet. I opened it up to borrow the bell-hiller mixing head for my H2 since I plan to piece up the X3D with my DUZI head.

Anyhow, when I took a look at the main blades in the X3D kit, they are not E489. They are a totally different blade, much narrower and look to resemble the main blades that are included in my Ecureuil 350 kit. (another kit that I havn't pieced together yet)

I'm wondering if MS happened truly meant to provide the X3D with these blades or if it's a mistake.

Raz
10-26-2006 Over year old.
 
 
DarkHorse1
Senior Heliman
Location: Gloucester UK
E489 CFC Main Blades 25,5 cm Hornet II- with weight $ 36.56
These are the ~12g skinny cord weighted CF blades that are shipped with the HX-3D and Ecureuil 350 kit (I thought but not so). I suspect you are not using E489. Try the X-3D blades and see how they fly.

EDIT: Are you using these CP1 blades?:

E188 CFC Main Blades 22,5 cm CP $ 39.56

EDIT:
> main blades in the X3D kit, they are not
I see what you mean, sorry.
10-26-2006 Over year old.
HOMEPAGE  
 
 
Razmo
Key Veteran
Location: Chicago

This was a little off topic, sorry. I am using E489 on my H2. The one that has flight popping.

I just happend to be curious, why E489 weren't included in my X3D kit (not built yet).

The Ecureuil 350 is a 3 blade head and comes with different blades (glass, grey and narrow) than that of the X3D (so I thought) but to my surprise my X3D kit came with a set of two very similar looking blades to that of the 350 kit. They are not E489.

I'll have to compare them up if I get the chance tonight.

Raz
10-26-2006 Over year old.
 
 
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e-MS Composit Hornet > Flight popping.....??
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