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SHORT BROS NIMBUS SCALE 1:3.5

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Jilles
Posts: 222
Joined: 22 Mar 2015, 10:27
Location: Australia
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Re: SHORT BROS NIMBUS SCALE 1:3.5

Post by Jilles »

Wings are all painted and gear installed. Today the model was assembled in full and the nose ballast measured.
I used a bucket of water connected to a temporary eye-bolt in the nose cone
Also used a luggage scale, these are accurate within 50 grams
the scale showed 2.16 kg, the bucket with water and eye bolt 2.19 kg, the difference being the eye-bolt the scale does not measure.
I had temporary bolts in the wing stubs were the C.O.G should be and the glider was carried on those bolts by strings.
Because the pick up points are so low and the actual structural C.O.G on top of that, a stable attitude could not be reached.
It either moved forward or rearward when the required load was reached. A way to overcome this is to measure the model up side down, but I did not do this today.
With an estimated additional weight of 150 grams of fuselage paint the total flying weight will be 12 kg. This was my target so I am happy. with that.
I will now pour the lead weight into a plaster mold what will be shown on a future post.
The plan is to have the fixed nose weight at 1.9 kg so I can make final adjustments as required later and allow for additional weight to epoxy and finish the nose cone to the fuselage.
.
Attachments
balanced with bucket of water
balanced with bucket of water
W70.jpg
luggage scale attached
luggage scale attached
W72.jpg
W73.jpg
W74.jpg

Jilles
Posts: 222
Joined: 22 Mar 2015, 10:27
Location: Australia
Contact:

Re: SHORT BROS NIMBUS SCALE 1:3.5

Post by Jilles »

A plaster mold was made with a 3D printed part with the contour of the inside of the 3D printed nose cone
This mold was made some month ago so it could dry out properly. I am told that when you pour liquid lead in a moist mold things can get interesting.
Cooked the lead and poured. the surface is a bit rough but that works for me. Gives a good hold of the epoxy used to fit the weight in the nose cone.
Wednesday day morning is one of my flying days. I took the Nimbus to the field for a show and tell and got proper pictures because at home there is not much space. It was also a transport test to see if all works fine in the little truck.
Attachments
F02.jpg
F03.jpg
F04.jpg
F01.jpg
F05.jpg
F06.jpg
F07.jpg
F08.jpg

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Peter Balcombe
Posts: 1221
Joined: 18 Mar 2015, 10:13
Location: Clevedon, North Somerset, U.K.

Re: SHORT BROS NIMBUS SCALE 1:3.5

Post by Peter Balcombe »

Very nice Jilles.
We all look forward to hearing about the maiden flight which cannot be too far away now :)

Jilles
Posts: 222
Joined: 22 Mar 2015, 10:27
Location: Australia
Contact:

Re: SHORT BROS NIMBUS SCALE 1:3.5

Post by Jilles »

Nose cone with ballast was fitted to the fuselage.Epoxy and four M4 bolts do hold it to the fuse. Also two layers of glass was added over the joint line. Plastered builder bog around it and sanded into shape. The fuselage is now covered with a layer of spray putty and primer. Waiting a day to let is cure than do the final sanding. I use automotive acrylic paint in spray cans. For the once a year I do some painting it is not economical to invest in a compressor and spray gun. Not to mention the cleaning of the equipment required so it will work the next time.
Attachments
20190903_100731.jpg
20190903_100738.jpg
20190903_151755.jpg
20190903_151812.jpg

Jilles
Posts: 222
Joined: 22 Mar 2015, 10:27
Location: Australia
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Re: SHORT BROS NIMBUS SCALE 1:3.5

Post by Jilles »

Spray painted the top of the fuselage white, had an extensive masking exercise and sprayed the bottom red.
The masking was done three days after spraying the white otherwise the masking tape may pull the fresh white paint off.
Got some 6 mm wide black pin stripe tape to trim the joint line between red and white. I had 4 mm in mind but it comes in 3 or 6 mm so used 6 mm.
For the size of the model in the end it worked out better then 4 mm.
The color scheme is close to the original as it flew in the early seventies. The name Short Nimbus was painted on in the 1950's and not on the later paint job but I liked it, so used for the later version. Saves questions at the field what the model actually is.
Got some stickers made by my local supplier and the result is on the attached pictures
The last things to do are now fitting the main and tail skid, wheel and rudder. Then installing the electronic gear and do a final balance
Maiden flight is scheduled for the 28th of September.
Attachments
masked for red paint
masked for red paint
F10.jpg
F11.jpg
F12.jpg
F13.jpg
F14.jpg
F15.jpg

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VinceC
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Re: SHORT BROS NIMBUS SCALE 1:3.5

Post by VinceC »

Beautiful Jilles. What a remarkable transformation

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Peter Balcombe
Posts: 1221
Joined: 18 Mar 2015, 10:13
Location: Clevedon, North Somerset, U.K.

Re: SHORT BROS NIMBUS SCALE 1:3.5

Post by Peter Balcombe »

Very nice work as usual Jilles.

Sean Fitzgibbon
Posts: 86
Joined: 11 Oct 2017, 18:53
Location: Mitcheldean

Re: SHORT BROS NIMBUS SCALE 1:3.5

Post by Sean Fitzgibbon »

Superb project, impressive in every aspect!

Jilles
Posts: 222
Joined: 22 Mar 2015, 10:27
Location: Australia
Contact:

Re: SHORT BROS NIMBUS SCALE 1:3.5

Post by Jilles »

The Nimbus was taken to the field today to get rigging experience on the field and do a range test.
I have a 16 channel Taranis TX. Two 8 channel receivers are fitted. Two 3S-2200 Lipos for power supply with individual power supplies for redundancy.
Both elevator halves have their own servo and channel divided over the two RX's, an other redundancy measure. Same for the ailerons.
In total 10 channels are used. Also on board a high precision Vario/altimeter from Taranus.
All my vario's are programmed that they beep when flying in lift. In normal sink no sound is emitted. Only when experiencing excessive sink a constant low pitch tone is heard.
Apart from adding approximate 150-200 grams in the nose and coming up with some cover strips over the wing-fuselage joints all is ready to fly
These cover strips are shown on pictures of the prototype so will be to scale. Much better than tape that rips of the paint after a while
The flying weight will be 11.9 kg so just under my goal of 12 kg max.
Attached some pictures of the occasion today. For a change I am in one of the pictures to give an idea of size. It won't happen to again.
This concludes this built thread with only more thread to come after the 28th with either the good or bad news.
Attachments
20190911_090050.jpg
20190911_090116.jpg
20190911_090125.jpg
20190911_090138.jpg
20190911_090209.jpg

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VinceC
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Re: SHORT BROS NIMBUS SCALE 1:3.5

Post by VinceC »

Wow! 8-) 8-) 8-)

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