Dumas Aircraft "Mr Mulligan 303" 30 inch Conversion to 4 Ch EP.

[Dwain Dibley.]

Ordered yesterday came this morning, thanks K.LM.S  ?

This will be my attempt to convert this rubber powered model to 4 channel RC, at 30 " WS, it should be easy enough, and there are a few examples on Youtube to prove it.

Seems to be a decent kit like the smaller version I built, but I have spotted some duff timber in there, the scrap bin will save the day tho.

This should be a fun project. Ailerons will be the biggest challenge I think. I love the plane and intend to build the Big One at some point.

This will also be my first tissue over Lam film finish too.  ???  No pressure then !!

D.D.

 

 

 

 

 

 

 

Some comparisons with the smaller RP version

 

[Dwain Dibley.]

The model has a fair old dihedral, and the tip is supposed to be lifted. So to get the ailerons in the right place I have done away with the tip lift, making the wing flat on the bottom. To achieve this, I had to fit the main spar upside down and alter the end by rotating it 180*. The pics will explain better. It has worked well.

I have a question tho......How much should I reduce the dihedral by, or should I just leave as is.??

The plan says 1 1/4" under each tip and the wingspan is 30"

I will have to make a leading and trailing edge for the aileron, but that should be straight forward, with a couple of lengths of 3/16th from the scrap bin.

Also some servo boxes, I may just stick them in with tape to save weight.

D.D.

 

 

3 laminations at the leading edge tip

 

The main spars, the one at the back is how it should be fitted.

 

The cut.

 

180*

 

Plus the rib.

 

Some of the kits fit leaves a bit to be desired, unless that is on purpose.

 

Almost a wing.

 

 

Edited April 29, 2021 by Dwain Dibley.

[Dwain Dibley.]

Anyone got an idea re the dihedral, as I have to set it soon, so I can cut the ailerons out !!!

D.D.

[Bryan Lea]

With ailerons you can use scale dihedral.  Check out the 3 views and photos of the full size.

 

 

[Simon Chaddock]

Dwain

Just a small point but you may have the spar upside down?

On the full size the wing tips go up. 

There is no dihedral.

Mr Mulligan was a racing plane so is not blessed with much wing area. Keep it light!

Edited April 29, 2021 by Simon Chaddock

[Dwain Dibley.]

Thanks Brian.

Simon, It's a freeflight model, and I am converting it to 4 Channel RC, I have fitted the spar upside down on purpose to allow the fitting of ailerons.

Plans say 1 1/4" under each tip.

I am thinking half of that with ailerons, I think zero would be problematic.

D.D.

[Dwain Dibley.]

Managed to cut the ailerons out without removing the wing from the board.

I reckon if I did it again, I could get the raised tip and the ailerons, but it's a bit more work.

D.D.

 

 

 

[Ron Gray]

Text removed whilst I think of something more sensible to say!

Edited April 30, 2021 by Ron Gray

[Simon Chaddock]

Dwain

Fair enough for ease of building but of course the full size managed to have ailerons and the upturned wing tips. ?

 

Do you know what it was supposed to weigh as a free flight rubber powered plane and any idea of the likely weight as electric powered?

 

A rubber powered plane structure tends to be 'light' build to extract the best performance from limited power. You will be adding some relatively heavy components. Its not so much an issue of its structural strength in flight but its capability to survive a rough landing. 

 

 

[Ron Gray]

I was going to say that my Peggy Sue has a flat wing and that performs really well, but it is a wider chord and longer wingspan, in relationship to the fuse, than the Mulli.

 

Those were my words of wisdom, put in previously, thought about, removed, now put back in again.

[Dwain Dibley.]

3 hours ago, Simon Chaddock said:

Dwain

Fair enough for ease of building but of course the full size managed to have ailerons and the upturned wing tips. ?

 

 

 

 

I can see how to do it after a bit of studying Simon, I may well build another, as this was primarily an exercise to try tissue over Laminating film too.

It's all a bit of an experiment. I built the smaller version (44.5 cm), and kept it as rubber powered, just made a moveable rudder for trimming.

That glides very well, no powered flights yet.

I will look at the weights for you Si.

D.D.

Edited April 30, 2021 by Dwain Dibley.

[Dwain Dibley.]

I made the servo covers/plates, and set up a couple of servos to get the geometry right to set the control horns in the ailerons.

I also covered the ailerons in Lam film, and one has has tissue applied. 

I may use this motor, I won it many moons ago in a comp from Steve Webbs.  ?

D.D.

 

 

 

 

This motor pulls about 60 W at less than 20 A on 2s

[Dwain Dibley.]

Water shrunk, with a reasonable result. Gonna do the other one and then Easy Dope, thinned, 30%

Hopefully I will have the Tissue Looks, but with the Lam film durability. 

D.D.

 

From the top.

From the underside, You can see where I marked  for the Horn.

[Dwain Dibley.]

I have applied 2 coats of 30% easy dope to the ailerons and they are looking OK, I have also covered the bottom of the wing in laminating film.

Slightly harder to do on such a light airframe but OK. Took it steady and no warps. 

I soldered extensions on the wing servos, and tested them, they were OK too.

Made sure the runs were Ok.

The wing with just the under side covered weighed 22g.

D.D.

 

 

 

 

 

[Dwain Dibley.]

Wing +servos was 46g.

I have covered the top of the wing with Lam, and got a layer of tissue on the underside, my technique is rough but I think I will be able to get the hang of it.

I will attempt to get a closer outline next time.

Servos are glued in, it will be an easy cut job to get them out if I need to.

D.D.

 

 

[Dwain Dibley.]

I was looking at a couple of Videos on Tissue over Laminating film, and the main thread i picked up on was the tissue itself.

Basically the stuff you get in your average Kit is, well... not the best. So I have invested a whole £8 for 50 sheets of white high wet strength, and 10 sheets of orange ( my favourite colour) From HERE.   Good and Cheap.

The interweb is an amazing place.  ?

D.D.

[Dwain Dibley.]

After Gardening duties were over, I got back at it, and covered the top of the wing. I pinned it all down on some wood and left it to dry.

I started on the rudder and elevator, and constructed them so that when removed from the board they will separate from the fin and stabiliser.

I added extra lengths of 1/8th Sq to the rudder and elevator halves, they are the same size externally, the wood was added internally, to form a new leading edge.

While I was at it, I watched a storm roll in from Clee Hills.

D.D.

 

The Storm.

 

The Wing.

 

The rudder.

 

The elevator. I made the joining piece bigger, to take the wire joiner recess.

 

A comparison with the (201) Kit.

 

[Dwain Dibley.]

Separation has occurred here at Dibley Towers. YAY  ?

D.D.

 

[Dwain Dibley.]

Two fuselage sides. ?

Even tho it is redundant, I fitted the panels for the rubber motor mount, it seemed to be an important strengthening part. The bit of card was there to push the port side one (1/16th) out to the edge of the 3/32 stringers.

D.D.

 

[Dwain Dibley.]

Weather prevents flying today so more Mr mulligan.

D.D.

 

I chose to add the optional Gussets to stop the fuselage wracking.

 

 

[Dwain Dibley.]

Made my own variation of the removeable cowl, my one twists on like the smaller version, this way I can get to the battery without cutting a hatch. The structure is too delicate to do that.

Gonna cover the fuselage next, because I keep breaking the 1/16th sq stringers, that appear to be made from cheese, Yes......... Cheese Stringers.  ?  ?

Also got the motor mount sorted.

D.D.

 

The components 

 

The motor mount.

 

The swivelly thingy.

 

 

 

 

 

[Dwain Dibley.]

cowl is now cut and glued, I used the conventional block method to fix it to the firewall, which itself is removable. I didn't have to, but I needed something to take my mind off the slice of thumb I had to throw in the bin, after I cut it off making the servo rails.

I have managed to get everything on the C of G, apart from the motor, it almost balances with the wing on, but the tail feathers will be further back, plus the control rods need to go in, so fingers crossed EH ??

Look at the tiny Radio-Link RX, that is a 10 channel RX, can you believe it ?  £16.00, or  a tenner from Bang good if you want to wait. I got mine from Greens Models.

D.D.

The C of G is marked on the top rails.

The dreaded rails that caused my loss of flesh.

Teeny Weeny Rx.

Edited May 5, 2021 by Dwain Dibley.

[Dwain Dibley.]

My wet strength tissue arrived, I tested it under the tap. !!  The difference is chalk and cheese to the stuff supplied by Dumas.

I have enough to do the full size plane now. Should last me a few years.

Also bent the under carriage up, my least liked job, but it came out OK, this model has a rear brace leg.

D.D.

 

 

Undercarriage gluing. Had to add before covering, which is a bit of a pain, but easy enough to get around.

Servos not secured yet. i need to do that before the covering goes on, I am going to use balsa push rods, Z bend at the back, Swing keeper at the servo or maybe another Z bend ?

[Dwain Dibley.]

I covered the model after inserting the 4 pieces of balsa infills round the undercarriage.

I made the push rods from 1/4 sq balsa and wire, I went with a Z bend on each end. this was a bit fiddly but using heat shrink tube made the job easier, by holding it all in place while I got the lengths right.

It was then I remembered I had to make the rod exits. DOH!!

Did those.

The frustrating part is the stringers snapping all the time, due to the rubbish balsa. I will make my own next time.

Nothing is moving now the Laminating film is on.

D.D.

 

 

 

 

 

 

 

[Dwain Dibley.]

More covering  today,  got some of the new tissue on the tail feathers etc,

What a revelation it is to use the wet strength stuff, what can I say, you can pull it around, lift it, and generally mess about till it's right, with no rips or tears or crinkles.

Cosmic !!

D.D.

 

 

I have left the Laminating film uncovered where the side windows are, to save having to glaze them. Picture does not show it very well, I will attempt another one.

 

 

All tissued up.

Edited May 7, 2021 by Dwain Dibley.