Ultra Low-Speed Rotor System heli flight at HHAEFI 2010

[lolziloveminecraft]

Thatsssssss a nice heli you got there! it's be a ssssssssshame if anything were to happen to it!... SSSSSSSSSSSSSSSS... BOOM!!!!!! u and ur heli are gone

[mrfourtysevenman]

chop til you drop

[ht448]

finally a realistic RC heli

[HardlyDidHerSome]

OK. I got it finally. You were right. I didn;t know about the Xcell. Thought it had two parallel shafts. I'm with you...seems like you have enuff skills to do your own platform (chassis) that you can experiemnt off of. That is what I have been considering. Using HD components from others.

[HardlyDidHerSome]

We're not connecting.Changing the bevel and umbrella gear ratios would be a terrible task (as you stated). What I am advocating is to make the saft they rotate on spin faster. If it spins faster, the gears turn faster and so does the tail. It would be easier to make ratio changes to the gears before and after the safter than it would to modify those more specialized gears. But I will take my goofy self elsewhere and leave this to the gurus. Good luck.

[StormyMaxPerry]

@Hardly

That shaft is the mainshaft, the one the main rotor is directly tied to. Spinning the "umbrella gear" faster can only be done by spinning the main rotor faster and that's not going to happen. If I could design as you said an inline gearbox, one that could fit in the forward end of the tail boom and give me a 40% rise in RPM, that would do the job but size and strength requirements would make durability the next problem. New chassis needed actually...

[HardlyDidHerSome]

OK...been thinkin. Assuming your configuration is pulley #1 to pulley #2 to pinion gear #3 to main gear #4. Tail gears are inbetween the pulleys and gears. Make pulley #2 smaller to turn shaft faster. Allows tail to turn faster. But to keep rotor speed same, decrease size of pinion to compensate for faster shaft rpm, thus making the rotor spin at the same rpm as before. Decrease ratio #1 and Increase ratio #2. In the middle is the tail gears and they will turn faster. Am I goofy on this one?

[StormyMaxPerry]

@HardlyDidHerSome

Yup, you're "goofy" :-) The problem is you aren't familiar with the X-Cell Ion-X mechanics, or don't seem to be. The tail drive is basically a bevel gear riding on the teeth of a crown gear which is directly connected to the mainshaft. Only by making a larger crown gear or a smaller bevel gear can the ratio to the tail be raised. If this style heli were designed as you said, changing the ratios would be a snap but... THX for trying :D

[HardlyDidHerSome]

I had to deal with precision gears and clutch for telescope system once and appreciate your determination. Separates the men from the boys. Ha. May be lame but what about an intermediate gear box inline that uses comon gears and changes ratio to up rpm's? I really favor the idea of two parallel shafts up front so one can do stock umbrella but change pulleys for tail. Talk about a platform for experimentation. Your camera guy never responded to my email couple weeks back. Must be in berry field,

[StormyMaxPerry]

@HardlyDidHerSome

How did you try to contact my camera guy? Through youtube or...? He doesn't have an account here. What was the question?

[HardlyDidHerSome]

I wouldn't raise rpm either. That would be te easy way out. So hopefully the gears are available for you to speed up the tail. In either case, keep on it and post it please when you get there.

[StormyMaxPerry]

@HardlyDidHerSome

I most certainly will. This tail gearbox is already updated with gears to give me the most RPM possible, so it's at a dead end. If there was a miter gear of greater than 70T available at the front of the tail drive system I'd go that route but nothing of-the-shelf exists. I've made gears before and just may have to make some again...

[tmoney20one]

What type of flight times do you get with this change in headspeed? on what batteries do you use?

[StormyMaxPerry]

@tmoney20one

The battery pack setup is 12S, 4960mah from TannicPacks. Very old batteries but work OK on this low a current draw. I could fly for 25min if I wanted to push these particular packs to their limit. I normally fly for 10min, twice, between recharges. Power is used very efficiently in this model.

[gaetanboiv]

I like a lot your work. A Big Huey with his tail rotor elevated and a longer moment arm should give you more tr authority, clear the ground and keep this marvelous sound of flapping blades, Have fun.

[HardlyDidHerSome]

Don't give up. I think the answer is in compromise. For me, this rpm pops well but somehow sounds on the weak side. Maybe it's the whistle. Regardless, if you shortened the blades (a bit) and up'ed the rpm (a bit) the tail would have a better chance. If the tail lengt is an issue, maybe a 2-piece lifted boom using flex or an interim gear box? I think there is an optimum size for rc heli (100size?) and you have the talent to go get it. Please stay after it.

[StormyMaxPerry]

@HardlyDidHerSome

Sometimes the blade popping noise is very obvious but good forward (airspeed) is required along with a particular loading while changing direction. I was trying to force the sound to be more obvious during this flight but it just didn't go as expected. I refuse to raise the rpm, that would be 'cheating' :-) The boom and torque tube is already two-piece. A custom tail gearbox w/correct overdrive ratio is what's really needed.

[lunarrn]

Did you use an established aerofoil design, or did you create your own?

[StormyMaxPerry]

@lunarrn

For the main blades? They're MAH brand industrial heli blades, available off-the-shelf and have symmetric airfoils. Nothing special but their length at 950mm.

[atllex]

Is there no way to adjust the gearing of the tail belt gear? or teeth on the TT?

[StormyMaxPerry]

@atllex

As mentioned in my video's description, there's no practical way to change the tail rotor gear ratio for a faster spinning rotor. I'm already using special gears that allowed me to improve the speed by 15% and that's as far as I can go.

[lockout45]

Awesome stuff as usual steve

cheers Patty

[StormyMaxPerry]

@lockout45

Thanks! It's been over three years since I started flying this model and because of my distaste for dealing with video editing software have been slow in getting material worthy posting for public viewing. Also this was the best of the recorded flights, shot only a few weeks ago.

[TooSlow2Care]

excellent concept. i've been running my 600electric at ~1400rpm for the sound it makes. i have not experienced any loss of tail control.

have you considered a 4 or 5 bladed tail? the more surface area you can get back there, the more control surface you have thus increasing your tail authority.

just a thought.

Brian

[StormyMaxPerry]

@TooSlow2Care

Thanks for the suggestions but in the case of this heli they're not of much use. Anything extra back at the tail rotor adds too much weight to be effectively balanced at the nose. I need a faster tail not a bigger, heavier tail rotor. With this mechanics set that just isn't going to happen. One option is to drive the tail using a dedicated brushless motor, as the Minicopter Joker 3D does. That would allow any rpm back at the tail. But I'd have to tear up these frames to do it.

[oysterlicker]

@StormyMaxPerry Don't need dedicated brushless motor. How about new gears to get better ratio ?

[StormyMaxPerry]

@oysterlicker

...already answered, thanks.

[TheLipRipp3r]

....cool scale sounding sound!  lol awesome!

[StormyMaxPerry]

@TheLipRipp3r

Hey, thanks!