|Oct 20, 2014, 09:43 PM|
Yes I would of spent the money on a real one for the front then you wouldn't get the binding and it would have the damper. You could still get the wire to work. You just have to know were to bend it at. I just hope the extra drag on your tail servo works out OK! But again a lot of trial and error! Dam if you do and dam if you don't lol!
|Oct 21, 2014, 04:59 AM|
Your probably right on finding the right bend to make a castering wheel work out, I just couldn't find it. I can tell you a simple sweep aft of the nose wheel with one bend didn't work. In theory it sounds like it would be perfect but put the weight of a 12 cell above it pressing down and the strut locks up like its in a vise.
With the straight nose strut even with weight applied it stays rotationally free.
I would need some fancy bends to the strut or have it mounted in a good set of bearings for the castering strut to work out I guess.
In ground testing I really don't see the very small amount of drag created by the flex shaft to be any issue at all in flight.
The flex cable is routed in a gentle arc to the nose wheel so it's really smooth and free.
I base my suspicions on the fact I have zero friction in the tail rotor control rod the way I have it set up.
If the guys running stock setups with their control rods bent through the control rod guide don't have any issues I shouldn't either.
I know how much friction is in the tail control rod of the stock setup and the friction of the flex cable forward to the nose wheel is much less than that so I am hoping there will be no change in flight performance at all.
Today will tell the story and I am nervous but just like the initial tests with the fixed nose wheel tricycle gear which I was very worried over, and as it turns out I was worried over nothing, I am hoping to repeat that finding with the steerable nose wheel.
So today it's either ...or .
|Oct 21, 2014, 09:02 AM|
Works perfectly so far.
Just one flight into the steerable nose wheel and I can say without hesitation it works perfectly and is a blast.
Just did 90 degree rolling turns while on the ground so far but it was like it was on rails. The SK720BE works perfectly in contact with the ground. Didn't use any cyclic in the turns, just a little collective to get it moving and a little rudder for direction.
I'll continue to practice latter, just wanted to know it would work which it does very well.
In flight the performance of the tail is the same, real quick and sharp.
More practice when I get the chance and a video as well.
I am a happy guy....and relieved.
|Oct 21, 2014, 09:32 AM|
|Oct 21, 2014, 10:05 AM|
Now she understands.
Yup, it's 100%now.
It's a plank and a 3D helicopter rolled into one, but unlike the planks, wind doesn't bother it on take off and landing, you just power through it...because you can.
I would hope the manufactures would sit up and notice.
Skids are great....
But with todays FBL units with the SK720BE in particular, the addition of wheels opens up a lot of options.
I did have a manufacturer of a FBL unit contact me and say years ago I would never have had this work, feed back would have torn it apart.
Since those days nobody except some scale guys and a few factory ships has really tried it out and now we can see the stability of the newer gyros and programing.
We have to remember also they put gyro units in airplanes to and they taxi and they don't go crazy. I know its a lot different with helicopter FBL gyro control but the principle is still there.
I can't say that the tricycle gear is unstable even though looking at them, you would think so.
I have never had a near roll over on grass or black top and even my botched auto rotation stayed upright even though I broke a leg. (on the ship)
In the case of the G770 the wheel are lighter than the skids including the steerable nose wheel assembly.
The tail servo has no problem driving both nose wheel and tail blade pitch at the same time.
The interaction between main rotor pitch and the addition of tail blade pitch is not noticed on the ground because the control movements are so small.
Its a keeper.
|Oct 21, 2014, 10:08 AM|
|Oct 21, 2014, 03:16 PM|
|Yesterday, 09:31 AM|
|Yesterday, 09:44 PM|
|Today, 03:05 AM|
I put a lot of thought into this and I hope it will continue to shine for me.
That being said, I have only been into RC helicopters a couple years so I know I have much to learn. I only know what I know and I am sure some of that is flawed so I appreciate anyone's knowledge or contributions to help me out.
The dedicated servo wasn't used for a couple reasons.
1. Added weight.
I am still lighter than the stock skid gear setup and being 3D, that is very important to me. (even though I suck at 3D, light weight in any flying machine is important)
2. With the separate servo steering the nose wheel and with the tail rotor gyro being in "heading" hold the tail would not understand what's going on.
It would try to counter act the nose wheel turn every time while on the ground I would think.
I would have to put the tail in "rate" mode for ground ops and that would be just to much of a hassle.
With this setup it works very smoothly. Turn left or right. the nose wheel turns and the tail blades change pitch in the desired direction so they work together, not against each other.
There is a load imposed on the tail servo during ground ops of course but I believe it is acceptable. Being a 12 pound helicopter there is a lot of weight pushing down on the nose wheel so I try not to sit motionless on the road and mindlessly throw the rudder stick back and forth grinding the nose wheel into the ground. That's bad for the nose wheel and creates needless load imposed on the tail servo.
Its similar to the power steering in your car, you wouldn't sit in one spot and crank your steering wheel back and forth for no reason. Its bad for your tires and bad for the hydraulics or the electrics driving the system.
Start the car or my Goblin rolling a little before cranking in the turn and the load imposed on the entire system is greatly reduced.
In the case of the Goblin, the change in tail blade angle encourages the turn so the load on the nose wheel is reduced even more.
Just being real lucky with a direct path from the tail servo to the nose wheel with the Gold-N-Rod control cable was another benefit in making the system light and simple. Being nearly a strait line prevents any drag in the system being created by the cable.
The natural drag of the nose wheel control cable is so low that I really don't think the tail servo feels it or is slowed down by it presents.
Really excited to take it out for more runs but the weather here has tuned ugly preventing my progress.
Can't get in a hurry in aviation....there will always be better flying days.
|Category||Thread||Thread Starter||Forum||Replies||Last Post|
|Article||SAB Heli Division - Goblin 700 Review||CSpaced||Large Electric Helis||51||Nov 19, 2013 10:23 PM|
|Sold||Brand New & unfinished GOBLIN GOBLIN 500 RED||x5heli||Aircraft - Electric - Helis (FS/W)||3||Apr 30, 2013 11:37 PM|
|Video||INSANE RC Heli- The Goblin 700!||RobscoRC||Electric Heli Talk||1||Apr 15, 2013 12:05 PM|
|For Sale||ProHeli Blade MCPX / MCPX BL Goblin Canopy Fuselage mGoblinX Goblin Style||Howeroll||Aircraft - Electric - Helis (FS/W)||8||Apr 07, 2013 06:11 PM|
|For Sale||ProHeli Blade MCPX / MCPX BL Goblin Canopy Fuselage mGoblinX Goblin Style||Howeroll||Aircraft - Electric - Helis (FS/W)||1||Apr 01, 2013 01:18 PM|