Here is a list of all the postings Mike Rolls has made in our forums. Click on a thread name to jump to the thread.
|Thread: Damm where have they all gone|
Buy on line?
|Thread: Battle of Britain Day 15th Sept|
Terrific - haven't seen them in years, unfortunately, but I will never forget them flying overhead completely out of the blue at Guildford years ago just as I was packing up from a morning's flying. Six Merlins - magic.
My own O/D Spitfire (1/10 scale for hand launch) is probably not going to be ready in time - I'm a slow builder - but I am determined to have some sort of Spitfire in the air on the day, even if it is a 12" chuck glider!
Very true. Bomber Command had the highest loss ratio over the war of just about anybody. 55,000 deaths of chaps of an average age of 22.
That sounds great, Phil - wish I could be there to see it.
Go for it, guys!
As I am sure we all know, Wednesday, 15th of September is Battle of Britain day. This year the Battle is 70 years ago, and few indeed of 'The Few' are still with us. On another forum I visit, somebody suggested that as a very minor tribute to those days we should get as many moddels of the a/c which won the battle - the Hurricane and Spitfire - into the air. Doesn't matter if it is a 1/3 size super scale model or a KK 3/11 rubber model - get it aloft (and as the Blenheim and Defiant were on Fighter Command strength at the time - if you have a model - go for it)
|Thread: Aircraft Weight|
Incidentally, the spreadsheet I set up also uses the formulae from Alisdair Sutherland's book to calculate the CG position.
Yes - I also use a 'moment calculator' to make sure that the cg comes somewhere near. I ignored it once - and had to add three ounces of lead to the nose of what was otherwise a 16 ounce model!
Oh, should have said - I only use the spreadsheet when I am designing something which does not resemble any of my previous models.
Leaving aside the arguments (with which I agree) against using the Christmas Bullet as a prototype for a trainer, there are two ways or reasonably estimating the weight of a model before starting to build it:
1. Experience of similar designs - and I mean similar, not vaguely like, or
2. Use a spreadsheet. For this method you need to have roughed out the structural design e.g., 2x 1/4 sq. spruce spare 48 inches long, 4 servos at 1 ounce each, etc. This is the system I use and I find that I am normally within 10% of the final weight.
|Thread: Vic Smeed Popsie X2|
'C' grain is the best material for ribs.
|Thread: Cleaning sole of covering iron after covering with solar film?|
I've always used cellulose thinners on a piece of paper towel. Never bothered with letting the iron cool until the day I found myself holding a blazing piece of kitchen towel, which I dropped pretty quickly. Fortunately I was cleaning the iron in the garage with a bare concrete floor, instead of in the shed ankle deep in balsa shavings..
|Thread: Vic Smeed Popsie X2|
I should have made the point that, like balsa, spruce does vary in weight - although not to the same extent. I have assumed close grained spruce (usually pretty dark in colour). Some open grained spruce can be a good bit lighter, but not as strong, as the close grained stuff.
Yes it is - although you need to be careful i selecting it. Decent spruce, compared to hard (14-16 lb/cu.ft) balsa is roughly 1.6 times more resistant to bending, size for size., which is the important figure to consider in spar strength. On the other hand, it is roughly three times heavier, so weight for weight, hard balsa is the more efficient. When they want to achieve greater strength in bending, most folk tend to use the same size spruce as the original balsa, or perhaps a little smaller, but don't go down to the same weight - that would reduce strength, not increase it. for example, a piece of hard balsa 3/16 square will weigh about the same as a piece of spruce 3/16x1/16. Assuming that the spruce is arranged with the greater dimension vertically, the balsa spar will be roughly 50% stronger in bending,
Another thing to bear in mind, is the actual spar structure. The most efficient spar in bending, weight for weight, is an I-beam .
Just checked - it was indeed Bill Dean
The comments on the Southerner could be taken to mean that Vic designed it - I'm sure that wasn't the intention, but for the record it was a Keil Kraft design. Can't remember offhand if it was Bill Dean who designed it, but I think so.
|Thread: Tatty treasures|
1949 ED Bee
1951 Allbon Javelin
1951 ED Racer
1954 Elfin 149
1956 Oliver Tiger III
|Thread: Dad's final creation flies|
|Thread: Pilot, Builder or Both?|
I'm another designer/builder/flyer. Started modelling in 1946 with chuck gliders, been modelling ever since, although for a few years in the 60s it was static models only - no spare time to fly - but couldn't wait to get back to flying. Tried just about everything except helicopters, from indoor microfilm to C/L team racers, F/F rubber to sports R/C, etc. About 80% of my models have been own design - somehow, I just don't get the same satisfaction from flying somebody elese's design and even less with an ARTF - although I have put a few of them together.
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