cobratraxxas69

My Feedback: (31)

Hi guys,

I finally built a dolly that gives consisently awesome launches with my Clipped Wing Diamond Dust (will launch with 20-30 foot take-off roll everytime).

Parts:

1 Piece of 1/4" by 12" by 24" Poplar Plywood Micro-Lite (Birch is too heavy, Balsa is too weak) (from Hobby People)
4 Extra-light wheels (2-1/4 inch Diameter) (Part # HLFK1612) ( http://www.hobby-lobby.com/wheels.htm )-- these have to be drilled out a little to spin-freely on the axle (the axle is 4mm in diameter)
2 sets of 16" Inexpensive Wire Main Landing Gear (Part # RA1094) ( http://www.hobby-lobby.com/landinggear.htm )
8 Nylon Landing gear straps (5/32 inch) ( http://www.hobbypeople.net/gallery/567545.asp ) (Use 4 for each landing gear--they come with mounting screws)
8 Wheel collars (3/16 inch) (Hobby People) (I used 2 per wheel-- one spinning free on the inside and one locked on the outside--use Loc-Tite)-- do NOT use 5/32 inch wheel collars, they won't fit on the axles, I know this from experience!!

1 Dubro 4-40 Threaded Coupler (to go into the rear of the Dust-- between the ailerons) -- Super glue it in!
http://www.hobbypeople.net/gallery/866286.asp

1 U-shaped nail -- Hammer and Super glue it in! (Placed on longitudinal centerline, 1.25 inches from rear of plywood)--The threaded coupler from the rear of airplane goes in here
One 3/4 inch nail --Hammer and Super glue it in! (Placed on longitudinal centerline, 13 7/8 inches from rear of plywood)-- this position can vary, but near the part of the dust that lies flush with the plywood behind the fuel tank. This nail will go into the bottom of the plane.



Each landing gear had 2 wires. I placed the main wire (the one with the axle) on the inside for both the front and rear landing gear.

For the front landing gear, I placed the inner wire (closest to the center) 3 inches from the front of the plywood.

For the rear landing gear, I placed the inner wire (closest to the center) 3.5 inches from the rear of the plywood.

The 3 main things I discovered while trying out various launch dollys was:

1) Keep them light!! (Don't go heavy-duty, or the plane won't build up enough speed to take-off)
2) Make sure the wheels can spin freely and that the dolly goes somewhat straight.
3) Make sure the lite-plywood is wide enough to keep the plane from torquing off the dolly to the left. The torque of the engine will twist the plane off of a too-narrow dolly.

Smooth Spanky

Now this is a good idea!

Cobra, I'm clear on everything except for what the nails are used for and how the plane is temporary held to this thing. Any other info (pics???) would be appreciated.

Thanks!

SS

cobratraxxas69

My Feedback: (31)

Hi,

The plane is held to the dolly by 2 nails. #1) a U-nail (technically a 3/4 inch staple) is hammered into the plywood at the back of the dolly and #2) a regular nail (3/4 inch long) is hammered into roughly the center of the dolly (so that the pointy end comes up through the dolly which will penetrate into the covering of the bottom of the plane). Test fit the plane into the dolly first to decide where the regular nail should be placed, it should penetrate aft of the fuel tank.

A threaded coupler (basically a rod with threads on half of its length) is super-glued into the rear of the Dust and it slips into the U-nail at the back of the dolly to secure the rear of the plane. The center of the plane is then pushed onto the regular nail at the center of the dolly, so that a hole is made in the covering. I superglued thin K&S Engineering Plastic Sheet ( http://www.hobbypeople.net/guru/hps_475421846.asp ) onto the bottom of the plane (over the covering) to protect it and keep the hole from growing in the covering.



Here's some more pics to describe what I mean:

Mike Connor

My Feedback: (5)

I must say that is one rough looking Dust.

Why not use two small pieces of velcro that just pull apart rather then the nails.

cobratraxxas69

My Feedback: (31)

Hehehehe....I prefer "battle-hardened". The interesting thing is that it flies perfectly normal. But I'm sure that no one else has a rougher looking plane

I think the velcro is a very interesting idea, but I'm wondering if it could hold up (without letting go) to the significant thrust of the mighty engines we put on the front of our Dusts.

I'm also wondering if this dolly will work with my Weston Magnum[sm=rolleyes.gif]

vicman

My Feedback: (10)

Dang straight! There is some nasty pooo coming outa that Czec motor! I like the dolly tho and am thinkin pretty hard about doing one.

So it lifts off the pointy nail and escapes the U nail right?

cobratraxxas69

My Feedback: (31)

Yep, and it does it without drama!

bob27s

My Feedback: (19)

Very slick...... looks like a nice setup

SPEED JUNKIE

My Feedback: (14)

Mike,
Glad to see you haven't given up trying to huck the Dust![sm=lol.gif]
I like the old massive monster truck tire version better myself![X(]
It was always trying to make a continuos left hand turn on take off! That made for some very enteresting, no frightning, no painfull aborting proceedures!
Hope all is well and let's go fly together real soon![8D]
Wayne
Rev Bro #118

cobratraxxas69

My Feedback: (31)

Hey Wayne,

It's good to hear from you. It's funny but 2 of the last 3 times I've been to Rabbit, it has been WAY too windy to fly (the one good day, I had brought a rocket instead of planes). Defintely need to check weather.com before going out there anymore (2 hour drive each way )

I realized that the weight of the "monster truck" version of the dolly was killing me, the poor Dust just could not build up enough speed (plus it was too narrow, the plane was always torquing off of it to the left).

My old dolly weighed in at 4 lbs 5.6 ounces, this new one is 1 lb 11 ounces.

It's hard to imagine I even got the Dust to launch off the old dolly, considering that the poor plane had to pull an additional 4+ lbs, but it's amazing what full high-rate up elevator can do [:P]

Here's a picture of the old "monster truck" version of the dolly, maybe I could strap on a Dynajet to it or something

buildflycrash

Yea, but can you land on it?

Ed_Moorman

My Feedback: (1)

Hey Scott. I launch mine off the table. Let the rear legs down. Use a little PVC rack. It flies right off. Lands on the grass.

cobratraxxas69

My Feedback: (31)

Hi,

I used my dolly to launch my Weston Magnum with West .50 yesterday. It worked great!! But I did make a few observations:

1) It would launch off the dolly EASILY with a 9x7 APC prop. But my 2 runs with a 8x8 APC ended up with a full speed run (dolly and plane together) into the grass (no damage though ). It would not come off the dolly even with full up elevator. I'm sure that there is no way it would launch with a 8x9 or an 8x10 (as these are hairy to just hand launch).

2) The 3/4 inch nail near the center of the dolly was enough to keep the plane on the dolly. I didn't use the threaded coupler with the Magnum as the plane is too long. I just rested the fuselage of the plane on the U-nail in the back. Note: After 4 launches the U-nail had dug a little tunnel in the rear fuselage. But as you tell from my Diamond Dust, my planes all look a little rough Maybe you remove the U-nail before flying with the Magnum.