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EarlyBird
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Basil, I do dimly recall that Dremel call their chuck ‘multichuck’. Mine has a lithium battery and only seems to need recharging 2 or 3 times a year, so is very convenient. Whilst not as old as Peter’s, I’ve certainly had it long enough for the model number to be of limited use.

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Second aileron done.

 

IMG_20211213_092655.thumb.jpg.51090fd69d217509c0b472442eaef173.jpg

 

I can now fit them to the wings and finish the tips ?

 

That leaves servo hatches to do. There is some planking to do on the top but the fuselage is needed for that. All the strip wood has come from stock but the fuselage crutch is made from 3/16x3/8 ply which I don't have. Looks like I will have to make up a SLEC order but a sheet of 3/16 ply for two thin strips has me thinking that there must be an alternative.

 

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7 hours ago, EarlyBird said:

. . the fuselage crutch is made from 3/16x3/8 ply which I don't have. Looks like I will have to make up a SLEC order but a sheet of 3/16 ply for two thin strips has me thinking that there must be an alternative.

 

Laminate from thinner ply? E.g. 1/8 & 1/16 or three layers of 1/16.

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Why not just stick to a piece of 1/8" if it is not over critical.

Machines I have built using crutches are mainly for the build rather than strength for the fuselage when built.

If you have 3/16" slots then use a piece of 1/8"ply and make up the gaps where critical for assembly with a strip or strips of 1/16" balsa.

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Thanks for the help Peter. Moving on following the plan I have marked the position of the formers on the ply side plates and the location of the balsa crutch. Looks to me that the top of the crutch gives a reference line and the formers are at right angles to it. F3 seems a bit odd as it is 1/16 wider than F2 and F4 and the side plate is too big for it's intended location. Not a problem just added interest and head scratching with more checking to come. 

 

Curiously going back to the lite ply crutch puzzle this idea came from the instructions on the plan and in the article which says 'cut out the lite ply crutch' I was confused because the plan itself refers to 1/8 ply and 3/16x 3/8 crutch. My understanding is to assume balsa is to be used unless stated otherwise. It's all worked out for the best as I have 3/16 balsa and will have no need to trouble SLEC again.  ?

 

When someone did something stupid at work I just laughed, one day I was asked 'why do you laugh' my reply was 'because the only alternative is to cry which believe me I do feel like doing but seeing the boss cry is not good is it?' ???

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It is possible that my wording was not so clear.  Sort of a case "I know what I mean"

 

I don't have my original drawings and in those days we did not have PDFsso I can't say if it was the draughtsman who didn't put all the instructions in correctly.  I do know of draughtsmen who can and do make a dogs dinner on my plans.

 

Yes "balsa is to be used unless otherwise stated" is pretty standard on plans.

 

I think that it should have said "Cut out the light ply crutch plate"  

 

I cannot think of any plan ever that used very long narrow strips of ply for a crutch. For one reason the centre lamination would have the grain running across the narrow dimension with would be a horrible wak feature.

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Interesting developments. I have laid the formers on the ply plate and transferred the slot height onto the plate shown on the left side of the formers.

 

IMG_20211214_122539.thumb.jpg.a98eb72146ece6b32d37d379cb6d8445.jpg

 

F2 fits, F3 1/8 too small and F4 1/16 to small or the plate is too large.

 

Drawing a line along which to cut.

 

IMG_20211214_122602.thumb.jpg.c05e6af3918481ae0c12bb46ee7bfd08.jpg

 

Gives a straight line, the part to be removed is hatched. I am still thinking but this looks to be the best way to make everything fit. ?

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1 minute ago, Peter Miller said:

This is why real engineering drawings always are used working tothe dimensions, notthe drawing

Yes we always stated on any drawing DO NOT SCALE and also they were always fully dimensioned. The error at F3 is 1/8" and F4 < 1/16" so really there is only one appreciable difference between dimensions of formers and the side plate. I am going to cut down the side plate as shown. That's my decision of the day, do not expect any more. ?

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Certainly all the drawings at RR had the DO NOT SCALE message as well - amusing for me as the only ones I worked with were circuit diagrams ?

 

I've just started building a Chris Golds designed DH 71 Tiger Moth (the monoplane, of which just 2 were built and both destroyed - one in a crash and the other bombed at Hatfield in WW2).  There are a few drawing errors - both wings are drawn but the rib spacing is different on each, I discovered.  Not that it matters but, as I made 2 identical main spars, both my wings will be the same ?   It's a very comprehensive drawing with a load of written instructions, which helps a lot, but I'm regarding it as more of a guide than an oracle.

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17 hours ago, Peter Miller said:

I think.....no...I KNOW that if I had to fully dimension my plans I would never publish them

For me Peter I found the dimensioning part of design and drawing a real chore that I could have happily lived without. 

 

Having altered the side plates to match F3 and F4 it's time to investigate F3 being 1/8 wider than F2 and F4.

Here is F2 clamped to F3.

 

IMG_20211215_083820.thumb.jpg.825610168bc1506e3e4791dd579e1889.jpg

 

Not easy to see but F3 is 1/16 wider all around. I would have expected F2, F3 and F4 to be the same width making the side plates parallel. Checking the plan shows this to be the case. As F3 is liteply a file will provide an easy fix. Once adjusted I will continue checking and adjusting the formers to fit as necessary.  For me it's all part of the process which adds to the fun.?

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50 minutes ago, Ron Gray said:

The joy of CAD auto dimensions!

Not in the 70s? and when CAD took off in the 80s it was expensive. This all changed in the 90s with the introduction of the PC making CAD used more in the smaller Drawing Office.

I do remember the plotter being very expensive though, they used Rotring pens and whirred back and forth manically. Before the internet and pdf? 

 

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Yep, I know, I was there but I still kept my parallel motion board for many years even though I was also using CAD. 
 

It’s the same with many things that we used to do, pre calculators and pre decimalisation- ready reckoners were the order of the day for £SD calculations.

 

Well off topic but can’t resist the odd plunge into nostalgia!

Edited by Ron Gray
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3 hours ago, Ron Gray said:

Yep, I know, I was there but I still kept my parallel motion board for many years even though I was also using CAD. 
 

It’s the same with many things that we used to do, pre calculators and pre decimalisation- ready reckoners were the order of the day for £SD calculations.

 

Well off topic but can’t resist the odd plunge into nostalgia!

Continuing off topic, all pre-1950's planes and ships were designed and built using slide rules and log tables. The standard tolerance on the airframes of the Schneider trophy racers was 1/16th of an inches. The airframe dimensions were all in given in "tables of offsets and sixteenths" with respect to the fuselage stations, buttock lines and waterlines.

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All the formers are ready. Test fitted and doublers added some minor adjustments to accommodate the crutch taper on the F6-F9 will be done as they are individually fitted. 

 

IMG_20211216_072645.thumb.jpg.dbbe24cb989ac75d2af88f0fbe33dd42.jpg

 

Start assembling following the usual method with the formers at right angles to the side plates glued to one side then add the second side on top.

 

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