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Design & Build Dornier Do 24

A bit of a challenge

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Robert Parker17/03/2019 16:50:55
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916 forum posts
1175 photos

Hi All,

More applications of Poly C to the wings today as well as experimenting with the receivers. I intend using two receivers on this model to make life a little easier at the patch, 1 located in the fuselage operating the rudders and elevators and the other in the wing for everything else.

My radio equipment is a Spektrum DX9 using a 4 channel receiver in the fuselage and a 6 channel receiver in the wing. I bought a new AR620 as it has no antenna and a AR400. I have never done this before even, so all set up TX on and in bind mode and both receivers in bind mode and both bound successfully however, on switching off both TX and RX's remove the bind plug and switched on Tx then RX's the 620 worked but the servos connected to the 400 barely moved, both RX's had separate power packs. Tried them both individually and they both worked fine.

So attempt 2. as above but changing the AR620 for a AR610 and re-bound both RX's bound and worked perfectly. I now have my receivers sorted.

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3rd, 4th and 5th coats being applied so far. In the background my new wing for my TN Lancaster is coming along well as the old one was beyond repair following a hard landing, new wing has liteply ribs and nacelle formers instead of balsa hopefully not added too much weight but gain strength..

Well back to give another coat of Poly C.

That's all for now

Regards

Robert

Robert Parker25/04/2019 14:05:42
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916 forum posts
1175 photos

Hi All,

Due to work commitments I have not done a great deal to the Dornier over the past few weeks.

I was a little disappointed with the Poly C as in a few areas the sheet covering warped / wrinkled in a few places but with a shape knife and some cyano most of them went back OK except for an area over the flap where the grain runs diagonally and I have a nice rippled effect which I have sanded and filled to be acceptable.

I have this week made the outer wing struts and changed the method of fixing to the sponsons as I was not happy with just using a wood screw so I opened up the underside of the sponsons and epoxied blind nuts on the hardwood I had previously fitted, much happier now.

Well mostly anyway, when I fitted the rear wing struts they did not align with the front ones as I had hoped. Still not the end of the world just looks a little odd from the front.

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The wing is now very solid and in parallel with the tail, now to patch up those holes and figure out how to make the diagonal brace between the front and rear cabane struts.

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Next I need to get the fuselage upto the dame level as the wing so more Poly C and cloth and decide how I'm going to get power from the battery in the fuselage to the wing, two ideas in my head at present.

That's all fro now

Regards

Robert

Simon Chaddock25/04/2019 17:23:51
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5483 forum posts
2878 photos

Those struts are aluminium?

I would simply use them!

Positive for the middle pair, return down the longer outer four. wink 2.

McG 696925/04/2019 17:44:22
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2710 forum posts
1015 photos

Hi Robert,

Nice you're back to the Dornier.

Regarding the 'swollen' sheet, I don't know if you did it, but best is to cover the balsa with a thin layer of sanding sealer before applying the glass coat & Poly-C.

It avoids the wood to absorb too much water during the process.

Keep it up, young man.

Cheers

Chris

Robert Parker25/04/2019 19:24:51
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916 forum posts
1175 photos

Simon, I wish I had thought of that earlier in the build, but there may be a way, just need to think a little on it.

Chris, I did coat the whole model in sand n seal, which is water based and no problems arose when I applied it it was only after I started applying the Poly C, at first they went back but just stayed there.

I try to avoid using traditional sanding sealer / dope as my workshop was a spare bedroom before building the benches. Wanting to prevent my wife from complaining any more than she needs to I do try to avoid strong odours of paint, dope etc which I do outside and leave the model in the sun house overnight to dry if I can get away with it.

Regards

Robert

Robert Parker28/04/2019 16:37:42
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916 forum posts
1175 photos

Hi All,

Well having given Simon's suggestion some thought I went ahead with electrifying the struts, although front positive and rear negative

dsc05819.jpg

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These self tapping screws to be locked in place with cyano. Before fixing in place the connections were given a good pull to check the crimping was nice and tight.

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These two connections will be bolted on when the wing is attached using spring washers. Probably not the neatest solution.

I have carried out a voltage check, 12.35v at battery and 12.35v at the struts.

Now I have sorted this out I can resume finish off sheeting the hull.

That's all for now

Regards

Robert

Robert Parker01/08/2019 19:25:45
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916 forum posts
1175 photos

Hi All,

It has been a while since I have done anything to the Dornier. Having intended spending some time carrying out house renovations this turned out a to be a bigger and more expensive project that expected, still I have built up a fair decent amount of brownie points from the wife who is VERY happy with the end result. so much so that I think I have started her thinking of what's next.........uuummmmmmmmm, time to disappear back into the workshop for a while.

Anyway back to the Dornier, this week I have glassed the fuselage along with many many coats of Poly C and am now looking forward to spending my time with the wet "n" dry, at the moment there is nothing to really show as the poly C dries clear and it all looks like balsa.

I have also been fighting the urge to start another model as I'm missing the building part.

That's all for now

Regards

Robert

McG 696902/08/2019 23:15:36
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2710 forum posts
1015 photos

Hello again, Robert;

Great to have you back in the shed.... and with a load of 'brownie points'.

If I'm allowed a suggestion, instead of 'overloading' your FG with coats of Poly C, why don't you try out the Freddie B formula? It's lighter, a lot easier to sand and gives a perfect finish even used on blue foam or Depron.

You can find it in my 'old' Ballerina build blog. Please have a look at page # 43 & scroll down a bit... really worth trying.

Cheers

Chris

Robert Parker03/08/2019 07:06:42
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916 forum posts
1175 photos

Hi Chris,

Thank's for that, I having read your Ballerina post, I recalled reading it at the time and over time it faded away in the old grey matter. Now printed off and filed for use.

Regards

Robert

Robert Parker11/08/2019 17:04:07
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916 forum posts
1175 photos

Chris, all I can say is wow "Freddie's formula", is great and as you say easy to sand though must add that a FFP3 or above dust mask is a MUST yes

Fuselage now ready for painting perhaps might get a coat on this evening if it stops raining long enough.

I'll try the wings next, which to be honest have not worked out as good as I had hoped for.

That's all for now, hopefully some photos next post.

Regards

Robert

McG 696911/08/2019 18:44:28
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2710 forum posts
1015 photos

Hi Robert,

Fine that you tried the 'Freddie Sauce'... and glad that you liked it. yes

Regarding the sanding, I try to sand outdoors by preference. If not, I tend to use it 'wet' with some plaster sanding pads which work a threat on large curved surfaces.

When applied on fiber glassed balsa, I also pigment the 'sauce' with a contrasting acrylic colour - usually light grey - to help as a guide for sanding.

Looking forward to seeing some result pics, young man.

Cheers

Chris

Robert Parker11/08/2019 20:03:08
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916 forum posts
1175 photos

Hi All,

Well the rain clouds have moved on since my last post and I have given the fuselage a coat of primer / filler and also given the wings some of "freddie's sauce".

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I must say that I am well pleased in how much stiffness the glass fibre have added to the fuselage. I did not use poly C on the fuse as I did on the wings as the balsa still has got some give in it, so I opted to apply the glass with 50% watered down pva. I know I have added more weight but she will be landing on grass.

I'm giving the final colour scheme some thought and considering the dutch or spanish schemes but nothing cast in stone at present.

That's all for now

Regards

Robert

Robert Parker08/09/2019 18:09:28
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916 forum posts
1175 photos

Hi All,

Having had a break for two weeks summer hols down in Sunny St. Ives in Cornwall, it's time to get back and do a bit more to the Dornier.

Today I have painted the final coat of paint.

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I now have to make the cockpit hatch and the three cowls and the three turrets the latter will be a bit tricky.

Now that the top coat is on the wings don't look too bad.

As this model is coming to completion I am thinking what next to build I want to build a plan / kit next and have three that are in my mind at present.

First there is the Dancing Wings DR1 at 60" span with a four stroke up front. From three motors to three wings

Second, a Veron Avro 504 IC poweredavro 504 a.jpg

And finally, a Cessna 02A a plan built model with a span of 51" single 40 upfront I did think about twin electric but being hand launched thought it a too risky with the fingers on release. This one has been in and out of my to build lists for years after watching Bat 21.

b21.jpg

All very different aircraft, still have some time before I make my final decision.

Back to the Dornier, next will be the cowls, turrets and cockpit hatch and weigh her to see if I have hit my target of 9lbs or gone over and order up the decals.

That's all for now

Regards

Robert

McG 696908/09/2019 18:22:46
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2710 forum posts
1015 photos

Your Dornier is just coming on great, Robert. yes

Getting a bit 'envious' here. Maybe I should try some drawing & scratch building if I ever manage to finish my Vicomte first, of course...

Cheers

Chris

Robert Parker08/09/2019 18:26:38
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916 forum posts
1175 photos

Chris, how is it coming along, you were not far off finishing it I recall?

Regards

Robert

McG 696908/09/2019 18:53:43
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2710 forum posts
1015 photos

I swear I've not been lazy, Robert. angel

I'm afraid I went back to an other of my hobbies being acrylic canvas painting. As I got an invitation for an exhibition at the end of 2018, I did spend my spring (& summer) at handling brushes and paint tubes...

And, yes Vicky is basicly built. Wing and tailplanes are ready to cover, the fuse needs its servos & pushrods positioned, battery hatch and floor to be added, etc... as they say > "80% ready, just 60% to go"...

I'm about to start the restoration of a crashed vintage Graupner glider now, but the Vicky will be next in line fore the winter months...

Cheers

Chris

Shaun Walsh08/09/2019 20:50:58
205 forum posts
13 photos
Posted by McG 6969 on 08/09/2019 18:53:43:

I swear I've not been lazy, Robert. angel

I'm afraid I went back to an other of my hobbies being acrylic canvas painting. As I got an invitation for an exhibition at the end of 2018, I did spend my spring (& summer) at handling brushes and paint tubes...

And, yes Vicky is basicly built. Wing and tailplanes are ready to cover, the fuse needs its servos & pushrods positioned, battery hatch and floor to be added, etc... as they say > "80% ready, just 60% to go"...

I'm about to start the restoration of a crashed vintage Graupner glider now, but the Vicky will be next in line fore the winter months...

Cheers

Chris

What Graupner glider are you restoring?

Simon Chaddock08/09/2019 21:51:33
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5483 forum posts
2878 photos

My electric Cessna O2 (Vietnam special ops,52" span) worked extremely well and the rear prop was no problem on a hand launch,

Complete

My fore finger and thumb could only just span the fuselage at the strut joint so were reasonably clear of the rear prop during the launch action.

I actually made it so the front prop could be switched off in flight to reduce the risk of prop damage in the belly landing.

The all black stood out really well at altitude.

McG 696909/09/2019 07:27:23
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2710 forum posts
1015 photos

Hi Shaun,

I inherited the crashed Graupner with quite a lot of damage to the wing and tailplanes with the initial idea to use it as a test bench to practise my covering 'lack of skills'.

The previous owner told me it was a Graupner Bussard from the early nineties. Mine has a 1800mm wingspan but following the info I found the different Bussards were all 2000mm... so, at the moment, I have no real idea what model it could be.

As the fuselage - being blown moulded PP - is still OK, I recently decided to restore it and possibly make it fly instead of using it as a simple covering test.

Some more research will be needed and as soon as I can make some time, I'll start the project...

Cheers

Chris

Robert Parker29/09/2019 17:44:53
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916 forum posts
1175 photos

Hi All,

Just a quick update, I have made the cockpit / hatch and made a start on the turrets and at long last made the diagonal brace between the fus and wings.

Decals are homemade and applied all control linkages have been done

Photos to follow if it ever stops raining

All that is left to do is a final two solder connections (need a new soldering iron old one just packed up) and I think were done.

Regards

Robert

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