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007's 'Little Nellie' MK II

Ground up build of my 1/4 scale Little Nellie

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Disciple of Autogyros23/10/2020 19:17:24
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40 forum posts
48 photos

Today, I've been working on the mast head.

mast 1.jpg

mast 2.jpg

The universal joint (from e-bay) has an 11mm outer with a 5mm hole at one end and a 4mm hole at the other. The 5mm end has a bolt attached which was then epoxied through the aluminium sleeve (made from the 12 mm ali bar) into the 10mm carbon mast tube. The mast tube is 330 mm long. I may shorten this later in the build though.

Richard Harris24/10/2020 16:18:07
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2054 photos

Mike,

Watching with interestsmile d

If you need any info just ask, I still have mine though she more of a hanger queen of late embarrassed

I still plan on drawing something for the mag up in the future, a bit more builder friendly though maybe next year.

If any of the mods see this could you move into the autogyro section please?

20201024_155659.jpg

Rich

Disciple of Autogyros24/10/2020 18:21:43
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40 forum posts
48 photos

Hi Rich,

Thanks and will do. As hanger queens go, it still looks stunning and as it happens, this view shows the underneath which is helpful for me. smiley

Just checking, the reference to " any of the mods see this"..... I've assumed that message for the thread moderators?

Cheers

Mike

Disciple of Autogyros26/10/2020 18:04:10
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40 forum posts
48 photos

I had to make a change to the tig welded section of the undercarriage as the angle was too high so rather than start all over, I epoxied half of a universal joint inside each side of the crutch so it acts like a hinge point with some Ali rod, which will be inserted within the undercarriage carbon tubing. I'll be able to reduce the angle of the undercarriage struts and fix in place when fitting the suspension arms.

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Edited By Disciple of Autogyros on 26/10/2020 18:11:16

Disciple of Autogyros28/10/2020 17:11:27
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40 forum posts
48 photos

The engine/suspension mounting plate is made from 1.6 mm GF. It's bolted to the carbon mast. To prevent the crushing effect on the CF tube when bolts are tightened, I inserted 8mm (approx) wooden dowel inside the CF tube at the point where bolts go through. The engine stand-off's are made from 6mm Ali tube and the engine mount is made from 1.6mm GF.

mm2.jpg

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mm1.jpg

Disciple of Autogyros29/10/2020 16:25:23
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40 forum posts
48 photos

The rotor head plate for the blades is 1.6mm GF. I made a guess at the measurements for this. It's 50mm wide and 174mm long. The pilot holes for the blade bolts are 60mm from the centre. The flanged bearings has 11mm flange, 8mm o/s dia and 4mm i/s dia. The bearing plates are 1.6mm GF.

Rich,

Question, do you think this is about right?

head 1.jpg

 

I also added a 3mm ply spacer for both baring plates. One can be seen below

head 2.jpg

head 3.jpg

Trial fitting all the bits, it seems to work ok. The bearing spindle is made from 4mm silver steel. I think I'm going to need a longer one though.

head 4.jpg

head 5.jpg

Edited By Disciple of Autogyros on 29/10/2020 16:27:52

Edited By Disciple of Autogyros on 29/10/2020 16:52:39

Richard Harris29/10/2020 23:31:12
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2223 forum posts
2054 photos

Mike,

I was lucky enough to have a number of conversations with Ken Wallis where I quizzed him on how he build WA-116. Believe it or not, like you, he inserted wood into the aluminium tubing around the areas where bolt holes were drilled through, obviously the grain was in the correct orientation.

Rich

Richard Harris29/10/2020 23:35:00
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2223 forum posts
2054 photos

Out of interest, here is REX being put through its paces 10 years ago crook were did that go!

Richard Harris30/10/2020 07:48:04
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2223 forum posts
2054 photos

Sorry Mike,

That video makes no sense as part of the first reply is missing!

The original plate and blades were fitted to the testbed REX, the video shows one of its flights.

Rich

Disciple of Autogyros30/10/2020 17:25:21
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40 forum posts
48 photos

Hi Rich,

Thanks for the video and reply. I saw a DVD about Ken Wallis, he had a remarkable life, was very lucky through the war years and a very clever man. It must have been a fantastic experience meeting and talking the man.

Re my question, I just wanted to know if I was on the right track with the rota head dimensions as compared to your Little Nellie. I've not made a "two blader" before so it's a bit guess workish.

Cheers Mike

Richard Harris01/11/2020 21:43:21
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2223 forum posts
2054 photos

Mike,

I measured the flapping plate on mine and it is 140 x 40mm x 1.5mm thick, I hope this helps.

Rich

20201031_125244.jpg

20201031_125307.jpg

Disciple of Autogyros02/11/2020 15:16:26
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40 forum posts
48 photos

Hi Rich,

Thanks for the photo and info. Is Flapping Plate the proper name, or did I catch you on a bad day? wink

Mike

Disciple of Autogyros04/11/2020 18:49:03
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40 forum posts
48 photos

Hi Rich,

Next question....Re the blades, what length (tip to bolt hole) and width?

Sorry to be a pain.

Cheers

Mike

Big T10/11/2020 17:51:27
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224 forum posts
202 photos

Rich will he need some motor offset?

Richard Harris11/11/2020 09:51:35
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2223 forum posts
2054 photos

Mike,

Sorry for the delay in replying, I will measure my blades later but they are sized for my models mass and CG/ thrust line. I remember testing several different sizes and having to trim them back, the biggest problem with Nellie at this size is you are limited to their length as they get very close to the ground when rolling on take off (if the dimensions of Nellie are kept to exact scale).

The longer the blade the larger the tolerance between CG and Thrust line you can get away with (within reason), so its a bit of balancing act. With a horizontal tail plane fitted this tolerance is not so tight as it acts as a damper, but for me it doesn't quite lock right.

Tim,

I think (but I will check) I didn't use motor offset, if that's right I don't remember why!

Rich

Disciple of Autogyros11/11/2020 18:36:14
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40 forum posts
48 photos

Hi Rich (and Tim)

No worries, I've not done any blade work as I've plenty to get on with. Like you I'd prefer not to have a tail plane but unlike you I don't have your skill and capability to fly tailless, so I may add a tail to help with stability.

I did a comparison with the 1:24 scale Airfix kit for some initial guidance. Converting the measurements to 1/4 size I get a blade length (tip to bolt hole) of 670 mm and width 44 mm, the width does seem a bit narrow though? That would give a rotor diameter of 1438 mm (or 56.5 inches). I have no idea how much this is going to weigh at this point so I think I'll leave the blades for now but your wisdom would be welcomed.

Disciple of Autogyros11/11/2020 18:55:39
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40 forum posts
48 photos

I trial fitted all the main frame components but it's made me have a re-think on the position of the servos. As they now are, there will be some interference between the motor mount front plate and the servo rods to the head Tee bar.

frame 6.jpg

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I've incorporated a kind of suspension to the rear wheels by inserting some silicon fuel pipe (as a dampener) inside the upper carbon tube with the lower carbon rod acting as a kind of ram. It might work!

sus 1.jpg

sus 2.jpg

Big T17/11/2020 17:49:31
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224 forum posts
202 photos

It might be an optical illusion but there doesn’t seem to be any rear tilt on the mast? All of my model gyros have at least 5 degrees, some more.

Richard Harris18/11/2020 13:03:37
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2223 forum posts
2054 photos

Tim,

Autogyros don't need a mast that's tilted back, the only reason I have done this on my designs is that it makes them easier to set the rearward tilt going 90 degrees to the mast which is around 5 degrees for 3 blades. It also helps achieving a good CG without the need for a ridiculously long nose, personally I think it looks better tilted back but would spoil Nellie.

Rich

Disciple of Autogyros26/11/2020 16:38:45
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40 forum posts
48 photos

The pod/ fuselage has been a bit of a challenge, as I don't have enough suitable foam to carve it from, so I used balsa planks over a some formers. The end result is not great but I can live with it, and it's light enough. I still need to rub it down a bit prior to painting.

pod 1.jpg

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I carved the nose cone from the last of my pink foam stock. I think I'll have just enough to carve the fuel tank and rotor head cover. The gaps in the balsa planking was filled using a mixture of Talc and non shrinking dope mixed into a paste. The resulting filler is easy to work with and when cured easy to rub down to a very smooth finish and smells great (bonus), I then glassed it, but as yet I've not completed the pre painting prep.

pod 8.jpg

pod 9.jpg

Glassing isn't one of my strengths, so it needs some rubbing. I may be able to live with it though. We'll see.

pod10.jpg

pod 11.jpg

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