Tricycle gear on a Goblin 770.

[A VIKING]

I was directed here to you good people as no one on the sites I frequent could tell me for sure.
I have a Goblin 770 that I have been flying a long time and from the beginning I wanted to put it on tricycle gear and pitch the skid plates in the trash.
I have thought about it and have come up with a simple way utilizing the existing rear gear legs with skids cut away and spring steel front strut to make some sturdy stabile (same foot print at the rear wheels position as the OEM skids) tricycle landing gear that looks way better than the skids on the Goblin fuselage and tail boom.
Weight should be comparable also due the removal of those large skid plates and front skid legs.

The real question is this...I have a SK720BE in it.
What kind of issues could I have in a rolling takeoff, run on landing or just taxi on the ground?
Some say I will have a big roll over tendency because of the action of the FBL while rolling on the ground.
I know that lateral cyclic should not be used, only tail pitch on ground turns.
Would this be correct?
If it did have a roll over tendency I would restrict my takeoffs and landings to being stationary with the wheels a little tight on the axels to prevent free rolling.

What do you guy's think?
Am I asking for trouble and big expense for a rebuild after the roll over?
Educate me on this.
Nothing I would like better is to do a rolling takeoff with a 770 Goblin and fly directly into 3D flight.

Like I said over on the Skookum forum my wife says if it doesn't work I can put a string on it and pull it around the house behind me.

Thanks!!

[georgi UK]

=] any takers??!

[treotraveler]

Originally Posted by georgi UK

=] any takers??!

To what, buying a Goblin 770, a Skookum 720, scratch building 3 wheeled landing gear, then rolling it on rough pavement, gravel, dirt and a rough lawn with ruts and divots? Just to test what the OP wants to do?

NOPE!!

I think the OPs wife has the right idea, tie a string on it and pull it around the house. Common sense says, doing rolling take offs and landings would freak any fbl contoller out with the vibrations and gyro action. Outcome eguals tip over....

[SidewaysLS4]

It could mostly work. Mini Vbar in this thing:

AH-64 landings.wmv (2 min 28 sec)

[goodhunting]

... IF you put a forward angle on your main shaft... it could work...

most of real helicopters (military more evident) have a main shaft at a give or take 5 degrees forward tilt. This is so, that when they are in a forward flight, the passengers would sit level with the ground...

this way, when lifting a scale helicopter off the ground... you take the tail wheel off first and the forward ones will follow...

if you find the sweet spot just prior to taking off the ground... the helicopter will roll forward...

similar thing would happen at landing...
just be careful because the giro will compensate for everything and such heli would be keen to tip overs...


gh

[A VIKING]

OK, done here.
Thanks.

[A VIKING]

Just as a point of interest for some of you guys the tricycle gear works perfectly on my Goblin 770 with absolutely no bad tendencies on ground roll at all.
I started with a fixed nose wheel but after a lot of flight/taxi time and seeing its really easy to control I just created a steerable nose wheel. Now I can actually taxi with turns.
Still in the early practice phases of the steerable nose wheel but what little I have done so far tells me it will work really well also, just like the fixed nose wheel.
The nose wheel is driven by the tail servo but with careful placement of the Sullivan Gold-N-Rod I had very minimal drag in the system.
Anyway it works really well and I would encourage any of you to do the same on your scale ships.
The SK720BE does the controlling and has no issue at all with contact rolling on the ground. I have bounced it pretty hard on landing and bounce across rough spots on the road where I fly and it doesn't affect the SK at all. No feed back...no craziness.

Goblin 770 Tricycle Gear and Steerable Nose Wheel (1 min 7 sec)

[Heliwhisperer]

The old bleach bottle Bell 222 fuselage for the Kyosho Concept 30 had a self centering spring loaded retractable nose wheel that allowed the pilot to almost do a tight ground pirouette on an asphalt parking lot. It was pretty cool just 'driving' it around.
Ah the good old days!
HW.

[A VIKING]

I had great success with the controllable nose wheel but it couldn't pivot 90 degrees which limited maneuverability.
So now I have created a castering nose wheel for the ship.
Even though it's not a scale build, the incorporation of tricycle gear on a 3D ship and its success is noteworthy.
You guys building the scale ships have some really cool wheel gear ships to work with and I can see why they are so cool to fly.
I might have to try out the scale side.
Wheel gear is super fun.

Goblin 770 Castering Nose Wheel Taxi Test (6 min 12 sec)

[Keyrigger]

So the question begs to be asked, have you tried reversing the pitch to see if it will move backwards or is the down thrust too much for the wheels to handle? Looks very good for maneuvering otherwise.

Don

[A VIKING]

Funny you should ask, yes it will roll backwards with negative pitch but it rolls backwards much easier by pitching back with cyclic on the main wheels and applying positive pitch with the collective.

So yes, the answer is, it will parallel park.

[Keyrigger]

LOL. Nice.

Don

[Gladius]

Any plans on adding retracts? That's what I really want to see.

[A VIKING]

Originally Posted by Gladius

Any plans on adding retracts? That's what I really want to see.

Retracts are super cool but....
I have no plans to tackle that one with the Goblin.
I wanted something I could taxi while remaining light weight for 3D flight and also be strong enough to take some abuse. The fixed gear meets all those requirements.
I will leave the retracts for a scale build.

[Varc]

I take it this means your not putting this in a scale fuselage? If so, may I ask why tricycle landing gear on a pod+boom 3D helicopter? Why not just the normal skids?
If you are going scale, what fuselage are you gonna use?

[A VIKING]

Never say never.
I hated the look of the Goblin skids and thought wheels on the 770 would look much better.
I fly from blacktop so I wanted to ditch the skids. As it turned out the tricycle gear is actually lighter than the stock Goblin skids so it was a weight improvement also.

In doing a little research on ground ops with wheels I was given a lot of cold shoulders but was directed here to you guys by georgi UK who has given me a tremendous amount of guidance and help in my RC heli addiction.
You can see the kind of responses I normally got with this project in the third post of this thread.
But guess what, its not only doable, its super stabile rolling around on the ground.
So most everything I was told about an RC heli not being able to taxi was wrong.

I do like to build, but fabricating a complete scale fuselage for the 770 airframe would be a little more time consuming than I can do at this point.

Are there any scale fuselages out there that would fit, or could be made to fit this airframe?
I want to stick with wheels of course.

In looking through the scale sub-forums I see many exciting projects. I may just have to become a scale builder.
I spent about 25 years of my life working Bell 212/412/214ST full scale so one of those would be great.
The Bell 214ST would be my pick as it is my all time favorite. Can't say I have seen any built in RC.

Thanks!