Hummingbird head stiffener - FF flight now possible - RC Groups
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May 06, 2003, 02:30 AM
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art4242's Avatar

Hummingbird head stiffener - FF flight now possible


After trying to fly my Hummingbird outdoors in any kind of wind >1 mph I realized it was going to be tough – any sort of large gust would get it swinging into the “death” pendulum where it was nearly impossible to recover. Also trying any type of forward flight I’d get severe pitch up when stopping, enough so that it was really not possible to fly faster than several mph without difficulty.

Doing more research on fixed pitch heli’s and Piccolo’s in particular, this wind sensitivity and pitch up are related to the “coning” of the main blades which are quite flexible. There are several suggestions on how to reduce this which involves adding a head stiffener and using stiffer (carbon) blades. On the Ikarrus Piccolo BBS I read of several variations on head stiffeners, and decided to make one of my own for the Hummingbird.

This is what I ended up with, luckily I have access to a mill so I machined a T-shaped cross brace out of stiff plastic mounted on nylon spacers (cut off aileron control horns).

WOW! What a difference. Fast forward flight is now possible, it still pitches up but much less and it is recoverable. And today I was able to fly (albeit wildy, but no crashes) in gusty 10+mph winds. I never would have been able to do that before. The controls actually feel crisper as well. Definitely a must have mod.

-Art
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May 06, 2003, 06:30 PM
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kenru's Avatar
Thanks for the idea. I just put a stiffener on my h-bird and although I haven't tried ff flight yet, it does seem to be more stable while hovering in the rec-room.

I made this out of a couple of 2-56 Du-Bro Ball End Links. Not as light as yours but it seems to work.
Jun 04, 2003, 06:21 PM
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An-Lone's Avatar

Re: Hummingbird head stiffener - FF flight now possible


Quote:
Originally posted by art4242

This is what I ended up with, luckily I have access to a mill so I machined a T-shaped cross brace out of stiff plastic mounted on nylon spacers (cut off aileron control horns).

-Art
Hi Art,

Do you know if anybody who sells the "head stiffener" mod for the hummingbird? I would very much like to make my own, but I don't have the tools to do it. Thanks!

Andy
Jun 05, 2003, 09:02 AM
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Steve McBride's Avatar
Good looking stiffiner!

Now switch to fixed pitch hornet blades and you should really be thrilled with FF!

Steve
Jun 05, 2003, 03:49 PM
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art4242's Avatar
Andy,

I don't know of anyone yet that sells one...I'm also pretty sure that the Piccolo stiffener's don't fit because the spacing is different.

I'm sure you could cobble something together that would work fine, Kenru's setup looks pretty straightforward. Or just make a plywood piece with holes, and use some wheel collars (or cut off nylon aileron control horn bosses, like I did) as spacers. a #2-56 screw will pass through the stock M2.5 hole, just use a nut.

Steve,

Yes, some hornet (CF) blades would be nice. I'm holding off on those, waiting to see if a h'bird CP upgrade comes out (and I also have 3 extra sets of stock h'bird blades as crash replacements that I haven't tapped into yet )

-Art
Jun 07, 2003, 11:35 PM
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For my Pic I just bolted a second rotor head on top of the existing one, and sandwiched the blades in between. Seems to be working well.
Jun 10, 2003, 11:11 PM
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The head stiffener has bugged me to no end. It is easy to make, but, what bothers me is if you watch the videos from Century (here), you will see very clearly something that looks very much like a head stiffener. It's the only white part on the blades.
Jun 11, 2003, 05:11 AM
Chillaxin dude!
BulletMaster's Avatar
yeah,
I see what you mean. Missed it first time I watched it. Notice that the only time it appears to fly without it is when the training undercarriage is on, and the heli is nowhere near as stable!

It's all a conspiracy!!!
Jun 11, 2003, 05:13 AM
Chillaxin dude!
BulletMaster's Avatar
yeah,
I see what you mean. Missed it first time I watched it. Notice that the only time it appears to fly without it is when the training undercarriage is on, and the heli is nowhere near as stable!

It's all a conspiracy!!!
Jun 11, 2003, 01:07 PM
Registered User
I'll add to the conspiracy a little more... This is the ad for the HB in the June issue of RCM. Notice the head stiffener?
Last edited by eeek; Jun 11, 2003 at 01:16 PM.
Jun 11, 2003, 01:09 PM
Registered User
ooops. Double post
Last edited by eeek; Jun 11, 2003 at 01:12 PM.
Jun 11, 2003, 10:07 PM
Chillaxin dude!
BulletMaster's Avatar
ah...all part of the conspiracy. I lull you into a false sense of security and then **WHAM** in with the ol' double post!!

LOL

what a nong am I!


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