take off dolly

[heinkel]

Hi all ,quick question .Is it possible to make a take off dolly for A 90 Size Blackhorse P-40 as i have given up on the useless retracts,cheers .

[Romeo Whisky]

Just seen your post and that no-one had come up with a response.

I would have thought it was possible to make a dolly for any size model. In WW2 the germans used them for full-sized aircraft. I don't have any models that big, but I would think that you could upscale my dolly design which works well. The main thing is to keep the dolly as light as possible, with big wheels for minimum rolling resistance and a fixed tailwheel (NOT castored). Be ready to input plenty of right rudder on the take-off run as torque effect may make it swing to the left (the full-size P40 was a bit of a pig in that respect I understand - hence the big rudder).

Hope this helps.

[Cuban8]

I'd suggest that you get the retracts sorted by retrofitting a pair of servoless types. I dumped the useless mechanical ones in my 63" span H9 P47 five years ago and retrofitted Hobbyking electric retracts, oleos and nice Dubro wheels. Been absolutely reliable ever since. Dump the silly plastic wheel well liners to give a bit more space also.

Take off dollies can be a pain, I've seen all sorts of designs over the years and while some work OK, most are troublesome, especially when operating on bumpy or just uneven ground. A model like a fair sized P40 (90 size, so 60" wingspan or so & 7 or 8 lbs maybe ? ) assuming a suitable dolly could be perfected, will also suffer when landing without wheels - small models will bounce and even a cartwheel usually doesn't do terminal damage. Chuck your P40 across the patch in a less than perfect, maybe a bit quick, wheels-up landing will ruin your day.

I can put some photos of how I fitted the servoless retracts in my P47 if it's of help.

Edited By Cuban8 on 25/11/2019 11:28:52

[Jon H]

Posted by heinkel on 21/11/2019 21:01:24:

Hi all ,quick question .Is it possible to make a take off dolly for A 90 Size Blackhorse P-40 as i have given up on the useless retracts,cheers .

Which part of the retracts is giving you trouble? Its likely a better set will help you out.

There is also the thorny issue of landing too hard. Warbirds wont accept the sort of treatment a sport model will. You might have to refine your landings and, probably, the setup of the model as well to make precise control of landing that bit easier.

[Chris Walby]

Tried a few dolly designs with little success on a fun fighter (electric). Ended up with a RX, servo and battery on the back wheel to hold it straight however the tendency for adverse roll on lift off generally meant it touched a wing tip and cartwheeled in (not very conducive when at 3/4 throttle!).

As C8 says, sort he U/C out or hand launch it and save collecting the dolly every time.

I do launch my 5.6kg Vulcan with a dolly via a 25kg pull bungee and its a very tense few moments to see if it gets off the dolly and drops its bungee (been there & picked up the pieces!).

PS - because its bungee launch the caster wheel is at he front!

[heinkel]

Thanks for the info ,i had a set of electric retracts that lasted one landing ,will try the dolly ,cheers

[Robert Parker]

Nice idea I will need one for my Dornier

Regards

Robert

[Former Member]

[This posting has been removed]

[leccyflyer]

Previous dolly thread

With a bit of forethought it's possible to fly off the dolly. letting it continue to run to the edge of the strip, to be retrieved when you've finished your flight.

[Ron Gray]

I too was concerned about the dolly remains in place and in everyone’s way so I did think about motorising mine and having a cheap ‘drone’ flight controller on board with a ‘return to home’ function. That way, after releasing the ‘plane the dolly would trundle back to the pits. I’ve not implemented it as I’ve gone back to hand launching the big glider that I built the dolly for.