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: Outrunner upgrade to Alpha 180|
I forgot to say that my set-up uses a 10x6 Graupner folder. Sorry about that.
My Alpha has been rejuvenated by using a Jeti 30/3, 3300 3S lipo and Jeti 49A ESC. Rate of climb roughly tripled, power on duration roughly doubled.
|Thread: Is your Club|
Six years ago, when I joined one of the clubs to which I belong, I was the only electric flyer. Now virtually all the members either fly elecric or both.
The other two clubs -one I have only been a member of for a couple of years but it is by no maens unusual to find more electric being flown than i/c
|Thread: What/how will we be flying in 25 years time|
At my age - wings and a harp!
|Thread: Are we an ageing hobby?|
Electric sports aeros
Slope (very occassional)
Started with chuck gliders in 1946/7
Flown everything except helicopters, from indoor microfilm to C/L team racers over the years
|Thread: power problem|
Might be a poor connection between motor and ESC - I had a similar problem with a small foamy a while back - one of the motor cabkes had fractured inside its insulation resulting in intermittent contact which sometimes coped but sometimes didn't.
|Thread: Comparative engine statistics|
I'm sure that if they had the opportunity, the manufacturer or distributor would want to ensure that a good example was tested rather than a poor one. Whether they had that opportunity or not I, simply don't know.
There certainly were greater discrepancies back then between individual expamples of the same motor than one would expect now, For example, I had two Elfin 149s, one of which was much better than the other. I don't think that can be the reason for the upward trend in RWs figures, however. With the exception of the twoTorp 15s, one of which was certainly a clunker, and the other may have been, dependent on just what sort of a load a 9x3 Tornado represented, there was a definite increase over time from motors which simply didn;t reflect what people were getting in the filed. Perhaps the variations between individual examples was even greater than we realised at the time, and Ron was lucky woth his exmaples of low poowered engines and unlucly with his powered ones, but that does seem to stretch credibility a biot.
They were indeed interesting times. I have always wondered about the speed with which Ron's figures escalated over tests. Like you, I am totally convinced of his integrity - he had a reputation second to none at the time. I do wonder if it was a case of hime becoming more at ease with the machinery being used, but obviously I have no idea,
I looked up the K&B test again - not the full one, but the synopsis in the Aeromodeller Annual and I had fogotten that he actually tested two examples, one considerably better than th eother. I do wonder if indeed he was unlucky with the samples he had and that they might have been both done on the examples used successfully at the Worlds (the '53 event was the first appearance of the motors). The poorer example only managed 10,600 on a Tornado 9x3, whereas the motor he used for the test did 12,200 - big difference!
Maddeningly, I can not find that he used a 9x3 Tornado on any other 15 he tested, but he did use a 9x3 Tiger on several which was turned at 11,500 by an Eifflander Special (rated at 0.249 BHP), 12,200 by an Enya 15-D (0.252), 12,2oo by a Frog 249 (0.252) and 11,100 by a Barbine B40 Testa Nero ().189).
Of course, I have no way of knowing if the Tornado was a significantly lesser (or greater) load than the Tiger, but the variety of figured do puzzle me,
All the best
Nostalgia in spades! The dynnamometer you are remembering was referred to as the eddy-current dynamometer and was introduced in 1954 by the late Ron Warring. He had been unhappy with the earlier torque reaction beam which he reckoned was subject to gross levels of error from a variety of causes, including windage effect from propellers. In his original writings on the dynamometer he said that existing tests were over-estimating actual BHP levels by as much as 100% and to back up his contention his first test was on the K&B Torpedo 15 which had won the F/F worls in 53 - and did again in 54.
He reported the K&B as produing 0.142 bhp (can't remember the revs off hand); it caused some ripples as tests within the previous year or two had given figures of between 0.25 and 0,30 for other comparable contest 15s such as the ED Racer, Elfin 249 and Oliver Tiger Mk II.
Oddly enough, Ron's tests very quickly showed an upward curve - within a year or so of the K&B test he reported the AM 25 as reaching 0.181 bhp, and good motor though it was, the AM was no match for theTorp. Other 15s - Enya 15D, Webra Mach-1, Frog 249, etc., were also soon reported as having ouputs well in excess of the K&B. No explanation was ever forthcoming.
As you say, the system used by the MAP plans service was pretty useful - although needed using with a bit of care as it tended to lump together motrs od very differnt characteristics (and there is the occassional howler in the listings caused, presumably, by transcription errors over time)
A long time ago (in a galaxy far, far away) when the Aeromodeller did engine tests they included RPM figures for typical prop sizes, Although the way they did it wasn't perfect - like running tests for, say, 2.5s but using different props, the principle was very good and for more useful for the vast majority of folk than being told engine X gave such and such a BHP reading at so many RPM.
It would be extremely helpful if engine and electric motor reviews were to include such figures.
|Thread: RCM&E plans|
I don't know if this is the right place ot ask this question, but it seems reasonably logical.
Is there anywhere on the site where the various RCM&E plans are listed - and hopefully purchasable on-line? I can't fond anything on the site that links to such a list.
|Thread: Motor Specifications|
4mm studding will be adequate and yes, I would use locknuts even though electric motors have very little vibration.
|Thread: Treating balsa after construction?|
no it doesn't - unless you are over vigorous with the sandpaper. On sanding sealer - why? It is less efficient for this purpose than ordinary dope - but in any case you don't need to use dope or sanding sealer if 'tex is to be applied.
What do you intend to cover the wing with? Assuming a shrink film or fabric, as has been said you don't need to use anything, although Balsaloc or Balsarite will help adhesion, particularly if there is any ply to which the covering needs to be stuck. Can't understand anyone worrying about Balsaloc inducing warps on a normal structure unless you grossly over apply it.
On the other hand, if you are going to cover the wing in tissue, using dope or banana oil on the stucture will be a definite help in adhering the tissue, using more dope as the adhesive. Don't use sanding sealer for this - no point. It is simply non-shrinking dope with a filler. The filler adds weight and degrades the adhesion, although not really enough to matter.
If you intend to cover with silk or nylon it is essential to dope the structure.
One thing to bear in mind - any of these substances - Balsaloc, dope, etc., will raise the grain of the wood slightly and you need to sand the structure after applying them and before covering.
|Thread: Flick Roll. Dangerous ? A little advice please.|
To avoid a repetition, in the words of Hanno Prettner "To avoid crashing - fly higher"
|Thread: Best bang for buck model.|
None of you ever flown a chuck glider? For sheer low cost, nothing can compare. For fun - depends on you!
|Thread: Round the pole|
If you can still get the dual head set-up that can be fun. At Three Kings years ago the juniors loved that set up for combat - cheapest possible models of about 12" span or less, try and chew up the other a/c with the propor just knock it down. A spot of cyano and the loser would be airborn again in minutes. Carrier deck was fun as well.
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