It will soon be time to test fly my ME109 built from a Cambrian kit. It's a 42" span model that does not have a u/c, but I am not looking forward to handlaunching it, particularly for it's maiden trimming out flight!

So I'm wanting to make a dolly for it but have never seen or used one before, any tips would be greatly appreciated.

Generally, I was not going to make locating holes or anything in the wings, I thought just let the LE push against some short uprights on the dolly. The model has a fixed rudder, but I am going to fix a sepate servo and an old rx to the dolly to steer the tail wheel, if this is necessary.

Cheers,

Chris

Check with some of the combat guys, many of them have catapults to launch their scale aircraft and that would probably work a lot better than a dolly.

How did you like the kit? I have a Cambrian Spitfire 24 lined up as the next project.

Chris-s,
After building my Lanier Shrike .40, I was in the same boat as you. I wasn't so sure I wanted to do the test flight from a hand-launch. I ended up doing it anyway, but still wanted a take-off dolly of some sort for when my trusted hand-launchers were not around. What I ended up with was my T.O.D (Take Off Dolly) design. It works very similar to what you describe, with "pushbars" that stand up in front of the leading edge of the wing. Like your plane, the Shrike has no working rudder(s) and at first I thought about some exotic way of adding steering to the dlooy. However, at least with my Shrike, it does not stay on the Dlooy long enough to really require much of any steering. I just have a helper point it into the wind, or slightly to the right of the wind (it tends to torque the dolly a little left as it accelerates) and in a blink of an eye, it is up and away, while the dolly rools to a stop. I will try to include a picture of the dolly below, but if you need more info, you can e-mail me for a better description and more pics.

Good luck and have fun.

Lee

Just from another angle...

Plane set in dolly, as it would prior to take-off. My T.O.D. isn't real sexy, but it was cheap (materials all lite ply from scrap box, plus some wire axels and old wheels), and works VERY well!

Lee

Thanks for that Lee, I made one up out of some piano wire, looks a bit like some sort of modern art piece made from coat hangers!

The ME had it's first flghts yesterday as part of the scale competition, the wind was gale force, so we went without the dolly and all went well!

She also got first place in the fun-fighter class so I'm doubly pleased.

Cheers,


Chris

http://www.hangarspace.co.uk

Wow, that must be a bi*ch to land on!

Minn...yeah, some of the wise a** flyers at my club keep offering to put it back out on the field for me just prior to my landing, LOL! I keep declining their offers though! Actually, most of them just stand back and gawk once I blast the Shrike off, as it does tend to raise ones blood pressure in flight! The tak off from T.O.D. is the least of it...

Lee

I made a dolly (not girl type) with uprights like you said then
I made a steerable tail wheel with another reciver and battery
for rudder only that way steer on take off. CU

Hi guys, I´m flying from a rather bumpy grass field and so far my dolly starts have been very critical since the dolly will not track well but veers away in any direction. Therefore I´m now building a dolly with steerable aft wheel but instead of adding another receiver and battery to it I will try to use a servo lead which I hope will "pop out" when the plane leaves the dolly. Have you ever seen or heard of anything like that..??..if so please direct me...thanks.!
BTW, John can you share with us pics from your steerable dolly setup..?
....Cheers/Harald

Well, now I´m about ready for testing my steerable dolly with "pull-out" servo lead........wish me luck......Cheers/Harald

I think you are missing something. You need the wing holderss in FRONT of the wing, not behind it. The thrust is gonna pull that thing right off the dolly.

Is that you Jaime? If so, how can you talk about Spitfires when the Dak is still grounded?


BTW Chris-s, combat catapults work very well -- check the Combat forum here on RCU

Dohh, double post

Whats up guys ? I was just wondering , or the thought just popped into my head, if one of these dollies can be used for a 2 meter sailplane? thanks.

Exocet - valid point - but if you look carefully on the right hand side photo you see a pianowire sticking out which engages a hole in the fuse bottom. That worked nicely on my previous dolly so I kept it....! Triangles at the back only to keep it on an an even keel. Have not tested yet due to bad weather....[&o]........

RC-Fiend....sure thing, why not on a sailplane........Cheers/Harald

Just to keep the idea and the thread alive, here's my original contribution. I hope it works.......

root

The control-line speed planes use dollies.. with a "mousetrap" lock to hold the plane on the dolly until sufficient airspeed is developed to lift the plane and dolly off the ground. At that point, the mousetrap releases the wire s which fits -over- the wing and the plane flies away.
The dollies are generally 3-wheeled, and will go straight once the plane has left.

I made it 4 wheeled to track better/straighter.

I cut another 6.4 ounces off the platform and considered a steerable rear wheel with an added servo, battery and Rx but the frame is way to flimsy with only 3 wheels for a smooth ride on my club's grass runway.

Howdy guys, I doubt that all is said above about dolly design so I will try to "revive" this thread. Plan for another dolly design and want more input....THANK YOU....Cheers/Harald

PS...you may wonder about my "pull the steering cable" design in post #11 above..?? If you get the dolly design info flowing I promise to tell the whole story later......DS

If possible, try to "widen" (or something similar) the bottom of your firewall. Drill two vertical holes in it. Make your landing gear from piano wire and in an "H" form with the bottom legs of the "H" much longer than the top legs (you'll need more than one piece of piano wire as well as some copper wire wrapping and soldering will be required). Bend the bottom legs of the "H" outwards - this is where the wheels will be attaching. The last 1/2 in. or so must be horizontally bent to act as wheel axles.

The top two vertical posts of the "H" slot into the drilled holes of the widened firewall. It is very important for this to be a loose fit. The whole idea is that the "H" with the wheels will drop away from the aircraft the moment it gets airborne. Be sure to use hardwood to drill the two holes into. You don't necessarily need to use the firewall - just mount the landing gear where it's suppose to go. The firewall just worked well for me on my 049 C/L aircraft.

Good luck
Louis

A lot of CL guys use dollys (or is it dollies?). Search their forums for some ideas, too. They are basically wire frames with a TE stop that is hinged. The other end of the stop is trailing under the airplane. As the airplane rises the drag wire releases tension on the rear stops and the dolly falls free. I've never built one but have seen them in action. Paint 'em real bright- they tend to hide in the grass!

I've some some field tests to find which dollies actually work and which eat planes.

See Advanced Dolly Design on RCG