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moonglow V1build

balance problems with trike undercart.

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Geoff Parkes12/02/2019 09:49:27
99 forum posts

Is anyone else building one of these planes , it was a free plan a couple of RCME issues ago its a 60,s style aerobatic plane with trike undercart, the plan leaves several areas up to the builder to sort out, I have built it for electric power no problems there, its got a 5055 motor, 70 amp speedo,15x8 prop. I have not watt tested it yet but on 6 s it seems to have loads of power, during the build I kept checking the C/G balance, keeping the tail light, the usual things that you check when building lecy. planes.The problems started when I tried to balance the plane on its wheels for the first time, I had previously balanced the plane with a slightly nose heavy C/G but tying to get the plane to balance on its wheels was impossible the tail kept dropping to the bench (its a trike undercart) the legs are raked forward, there is no details of leg length or rake angle on the plan , the legs can only be located in one position the bearers are shown on the plan and the wing ribs are shaped accordingly, I have packed 65mm under the main wheels this gives a positive feel to the balance of the plane on the bench, but I have now so much negative angle of attack that there is no gap under the prop. I am at the moment converting it to a taildragger, but before I cut the hinges on the rudder to fit a steerable tailwheel does any one have any thoughts or suggestions as trike undercarts were a feature of 60, s aerobatic planes and it seems a pitty if I remove this feature if there is an answer out there that i am overlooking

Masher12/02/2019 10:09:50
1099 forum posts
160 photos

Hi Geoff

If you search, there are a couple of threads started on Moonglow. In this one Eddie provides some advice which may help. I am building one but am not as advanced as you are so can't help.

Denis Watkins12/02/2019 12:29:22
3660 forum posts
172 photos

Geoff

On the Outerzone plan, the main legs are vertical, with the axles just behind the C of G

And the model at my field, sits and drives on the mains comfortably

Am not keen on this raked forward idea as this is problematic on any model

Geoff Parkes12/02/2019 17:18:09
99 forum posts

Thanks to everyone for the help, as I spent 2 hours getting the screws out of the firewall that hold the nose wheel on yesterday afternoon, I think i will go as my first idea of converting to a tail drager, might take out the forward angle of the main legs, lets hope it does not induce a nose over attitude on take off, will advise , i think 6s on my set up will be to much, but a Watt meter will confirm, will advise once I can stop the prop. hitting the ground !

Denis Watkins12/02/2019 17:26:57
3660 forum posts
172 photos

For a taildragger Geoff

Looking directly down on the wing in Plan View

You should see some of the main u/c tyre in front of the leading edge

The absolute best position for the u/c is that the wheel axle is on the leading edge

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