Here is a list of all the postings Mark Elen has made in our forums. Click on a thread name to jump to the thread.
|Thread: Grumman American Cougar|
I got that 1/16 compensation sanded down today. There is a little more to do, but its getting close:
As I'm still awaiting the wood order, and the 1/32 ply for the side window pieces, I decided to start planking the rear, behind the windows. But before doing this, I wanted to get the fin front piece correctly slotting through F9. I cut a oblong hole in F9 before I fitted it, thinking I could sort out the angle sanding later. This took a while today, but it is now close enough that I'm happy to plank in the rear:
I then measured up the front and rear of the tapered section at the rear of the fuselage:
And then measured these, and worked out that each side would need 20 x 6.1mm planks, tapering to 3.35mm at the rear end.
I then made a start:
I'm just going to carry on with these now, up to nearly the top of the windows, then the planks need to go all the way to the front former, until the windows go in, i'm going to hold off doing these. There probably won't be any more updates for a while, as until the wood arrives, its just planking.
Thank you all for your kind comments.
Nigel, I do have a wire bender, but I'm not confident of getting the bend in exactly the correct place, hence the engineered axles. I will weigh a couple of collets and a chunk of wire and see how it compares.
Once the steering mechanism is complete, I will upload a video of it in operation.
I got a bit more done last night and today. I glued the two laminated formers in with epoxy, they had both contracted by about 1/8" so needed gently splaying out whilst they dried:
Then i got the small strips and bits and pieces done ready for when the ply arrives and I can get it cut and on
Its getting a decent size now:
Lastly, I got started putting a few laminations of soft 1/16 on the outside of the front former, this is to compensate for the rake and most of it will be sanded off, leaving just a fillet to glue the planking onto:
Today I have got the rear formers slimmed down and in. Here are the ones shown on the plan as solid that can be cut down on the scales before:
Here they are after:
That's 13 grams or just over half an ounce saved.
A bit more done the last couple of days,
I have got the top sheet on to the nose, I didn't have any 3/4" soft sheet, so I raided the scrap box for the softest sheet that I had. I ended up laminating the front end. Its a bit agricultural, but nobody is going to see it.
Don't look too closely at the above photo. I did most of this after I had had a pint or two.....
One of the upsides of laminating that top sheet, is that it has allowed me a good view of getting both sides somewhere near symmetrical when it came to sanding down the curves.
There is a bit more to come off this, but I will leave this now for just before covering, if it gets dinged during the build, it wont matter so much.
I also put up a couple of photos for some inspiration:
The above will be my chosen scheme.
I also made a start on the bracket for the nosegear steering pushrod. I have had to order a 2mm slot drill, so here is the embryo bracket without the slot:
Many thanks for your kind comments. I did think about doing something similar to that, but as it retracts forward and the servo is forward of it, it didn't work mechanically.
I got the servo bracket made up and in, then had a couple of hours with the mill and got the final bits made and they are temporarily in, I just need to make a small bracket with a slot to hold the pushrod in the correct orientation while it moves. Nearly there.
The next job on my list is to sort out the noseleg including a means of steering it.
Whilst in the middle of my last build, I was thinking about this and found this on YouTube: **LINK**
I made this up a while ago, though, I am going to re-make the blocks out of aluminium to save a bit of weight:
There is still a bit more to do on that, but the principle works and I'm going to carry on with the concept. I wanted to see how much slop it would have in it, surprisingly, there is very little.
The gear legs didn't come with any axles, and I don't fancy bending 4mm piano wire, and, getting the bend in the correct place, so this morning I have made an axle for the noseleg, out of a piece of 8mm silver steel that I had kicking about:
6 grams with a M3 grubscrew and a M3 nyloc. I'll take that.
|Thread: Gary's Brian Taylor P-47 build|
If you get really stuck with the prop hub, give me a shout. I could turn you something up if you have the dimensions.
|Thread: Grumman American Cougar|
Thanks for your kind comments. I hope you get on as well as I did. I found that only chamfering one side worked well, just don’t go too mad, they only need a little chamfer to get them to sit right.
I hit it tonight with a permagrit block, the ugly duckling is turning into a thing of beauty....slowly.
A bit more done today.
I wasn't going to post any more planking photos, but I spoke to a friend of mine today and he is following along, although he isn't currently a modeller. I promised to post up a couple of photos. Hi Brian!!!
The last piece is cut and sanded for one side, just need to get it in and the other side to do.
I'm very happy with how that turned out for a first attempt. Next job is to get the ends cut down and sanded to shape.
I'm waiting on a wood order for some 1/32 ply to make up the side window pieces, I'm hoping it will turn up tomorrow, but I'm not holding my breath. It has been nearly 3 weeks now.
Thanks for your comments. I’m going to take on board the slimming down ideas from both yourself and Danny earlier. I will make built up ailerons and flaps, and use a single servo on torque rods for the flaps.
As it’s going to be semi-scale, and I have picked out a lovely scheme for it, I would like to keep the internal linkages at the back to hide them.
I’m going to have a play with some glass cloth and poly C, with the view to how it subsequently covers with film. If it goes well, I may well follow your idea.
The fin is built up, and, it has been giving me headaches as to how to build it square. I don’t know how much it would save to build up the horizontal stab and elevators, but I may well have a go at both and see how they compare.
Once again, thanks for the pointers.
No photos today. Still planking.
Edited By Mark Elen on 20/05/2020 20:58:38
Edited By Mark Elen on 20/05/2020 21:00:49
Bit more done today. I got the fuselage out of the bending tool this morning, it didn't move at all. So I got started on this planking lark. I have been both looking forward to it and dreading it in equal measure. To be honest, I'm really enjoying it, although, I don't know if i'm doing it right:
I did the centre with straight 6mm planks, then whilst this was drying, I went flying:
An enjoyable couple of hours. On my own the whole time, it was good to do something 'normal' for a change. I haven't flown for about a year, so I had a couple of interesting 'arrivals' with the trainer before I got my eye back in. I then flew the repaired Ballerina, if anything, it is easier to fly than the Trainer.
Back home and more planks done:
|Thread: Gary's Brian Taylor P-47 build|
|Thread: Grumman American Cougar|
Thanks for your kind comments. Soaking and putting back in the formers might do it, but, I have got another set done and they are staying in the formers for another day or two.
Many thanks for your comments. This is 8 laminations of 1/32 x 1/4 ply. They have tightened up rather than springing back. Here are the two ends, the bottom one is still in the jig:
They have tightened up about 1/4", I can only assume this is down to me removing them whilst they weren't really set properly.
Whilst these are still sat in the jigs, I got on today with making a tool to pull the front end of the fuselage together:
That is going to get left for a couple of days to go off properly.
I'm nearly there with the rear formers now. But i'm not happy with the 2 laminated ones. In my excitement of a new technique, I rushed them a little and the 1/32 ply strips didn't quite go together properly. Also, I took them out of the jigs after a couple of hours. - they have both bowed inwards at the bottom and now need forcing out to sit in the correct location on the fuselage. The front one has a slight twist in it too.
Nothing for it but to make up a couple of new ones.
These new ones will sit in the jig for a couple of days before they get touched.
Either brave or stupid. My money is on the latter rather than the former😂😂😂
I was worried that it would be underpowered.
I had considered removing part of those Danny. The plan on outerzone calls for 1/8 x 1/4 uprights with 3/16 square cross braces. My plan from sarik, calls for 1/8 x 1/2 uprights but doesn't specify the cross members.
To be honest, if I was to hack some away, I don't think I would save much, as I remember thinking how light they felt when I was making them up.
Thanks for the info John. I have had a weigh of the engine bits this morning:
439 grams. It looks like I'm going to need that bit of extra weight at the back to balance these out.
I have pretty much decided to carry on 'per the plan' and see how it turns out. If I can get somewhere near 9 1/2 pounds I will be happy. Many thanks once again John for your kind offer.
I got a little done last night and this morning:
I have been thinking long and hard today, regarding the comments above, re the weight of wood, versus fibreglass nacelles.
Dennis Tapsfield’s article says that the original build weighed in at 9 and a half pounds, and it needed 4 oz of lead in the nose, along with a nicad for the retract servos. (I’m not going to have the luxury of a heavy nicad to use for balance)
Considering that the nacelles are pretty much all forward of the CG, is it going to be wise to loose roughly a pound from them, only to have to lug around half a pound of lead in the nose to compensate?
The other worries are that:
a) the nacelles will take a lot longer to produce, due to it being something I need to learn how to do.
b) I will need to fix them securely to the wing, considering the forces involved - this is my biggest worry.
c) It will be easier to cover wood with the same covering as the wing, than paint and match with the covering - no, this is my biggest worry, by far! 😂😂😂
Danny, Thank you for your kind comments. Praise indeed from the Master.👍
John, I will send you a PM. Many thanks for your kind offer that I will take up please.
Not a lot done today, as I had to work again. 2 days in a row. I need a rest now.
I did get F9 and F8 made up tonight. I'm hoping the wing plan is a bit more accurate than this fuselage one. The formers are all wrong. Some are too high, some too short, some too wide and some too narrow. Most are not drawn symmetrical and some of the cut-outs for the 1/4" spine are off to one side.
I have taken to measuring from the build so far for the widths, using the side elevation for the heights and using the best looking side of the former drawing to cobble together the formers. The sides angle back at 8 degrees, the top rake is 6 degrees, I have split the difference and am sanding them at 7 degrees so that I don't have to change the setting on my sander.
I'm going to strip some 1/8 and fill between the formers at the top to give the top formers a greater gluing area.
There is some planking coming up shortly. Something I haven't done before. I'm both looking forward to it, and dreading it in equal measure.
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