RSS Facebook



RCMF Donations

Enjoy using RCMF? How about a wee donation to help us keep you in the style to which you've become accustomed?

Welcome, Guest. Please login or register.
September 25, 2018, 09:53:45 AM

Login with username, password and session length


Recent Posts

Pages: [1] 2 3 4 5 6 ... 10
Dear All
I received word by carrier pigeon from Captain Manwaring
the Black Sheep Squadron C.O. last night.

Apparently the C.O. has made an almighty cock up.  :-X
He booked a holiday when of course he should have been
leading the BSS into battle for the first time on Friday.  ;D

However all is not lost as his 5 star holiday resort is not far from
Tibenham. So at least he is going to grace us with his presence
and probably give the Squadron a pep talk before heading off for
a slap up lunch.  :''

As was the case with most C.O.'s and Generals during WW1
he will be leading from the rear, normally about 35 miles at the rear.  :uk:

Before anyone gives me a history lesson.
This is written in jest and is not meant to demean those
who fought so bravely. Lions led by Donkeys.

Regards Phil G.

Dear All
Once again this year Dave Welsh, two standard  bearers
and a trumpeter from the 'Spirit of Coltishall association' will conduct
the remembrance ceremony for us. Unfortunately I was unable to
secure the services of a piper.

It is with great sadness that I have to write these words yet again.
Long term supporter of my events both at Coltishall and Tibenham,
Bob Payne lost his battle with cancer last Saturday and as usual
he was one of the nicest people you are ever likely to meet.

That is the sixth person we have lost in a little over two years.

Fly on my friend where ever you are.

Regards Phil Goff

You beauty, I'm in.
All round nice chap Tim E. is going to lend me his DR1 tri-plane.

Dear All
It must be getting close now as I am starting to get a twitch (steady)  ;D

I am struggling to have the Camel ready for the Black Sheep Squadron's first outing.

Does anyone have a WW1 model (60 inch ish upto 1/4 scale ish) which
they would consider lending or selling to me please.

As I would really like to be part of the act so to speak.
I know I have had plenty of time to sort something out
so it is my own fault. I think I am like a lot of modellers
I some times have a lapse of enthusiasm.

I was thinking 1pm for the first official flight of the Black Sheep Squadron,
that should give everyone who is taking part a good chance to be ready.

Regards Phil G.
RC Flight Chatter / Re: Wot4 Foam-e Mk2 wing fixing
« Last post by Michael_Rolls on Yesterday at 08:37:45 »
Usually they are spot on..

Sent from my SM-A300FU using Tapatalk
That's normally been my experience as well - haven't felt like following through, but perhaps one day the enthusiasm will return.
I did have one entertaining kit about 20 years or so ago (can't remember for sure which it was so I won't risk maligning anyone in error). A tail dragger, the CG according to the instructions would have been quite a bit on front of the point at which the wheels touched the ground, IIRC 95mm had mistakenly been printed as 65mm
RC Model Flying Events / Re: Osbournby Invitation Fly-in September 30th 2018
« Last post by pylonČ on September 23, 2018, 20:18:28 PM »
There will be Mayhem slots. Bring your Delta's or Gremlins Folks.
TV, DVD & Home Media / Re: Then and Now
« Last post by pooh on September 23, 2018, 17:01:14 PM »
PDR, thanks for the detailed background, always good to have an expert explain. I'm just a cynical bas***d and use the curve and my limited understanding to explain why buying an extended guarantee is (probably) a waste of money.

In my own business, I see electrolytic capacitors rated for a mere 1000 hours, yet I have equipment I constructed, using such capacitors, in service 24/7 for 18 years without a failure. I fact the only notable failure was the explosion of a complete unit. My poor excuse is it got struck by lightning...
Radio Gear / Re: Flysky fs-i6 spares/
« Last post by flynn on September 23, 2018, 16:30:17 PM »

either mode - $7.29
priority direct mail - 12 business days $2.63
expedited shipping - 8 business days $14.14

except they are under re-stocking at the mo....perhaps worth keeping an eye on?
TV, DVD & Home Media / Re: Then and Now
« Last post by PDR on September 23, 2018, 16:27:06 PM »
Only if they want to go bankrupt!

The "bathtub curve" is the sum of three curves:

1. The probability of latent manufacturing and material defects causing failures over time (an inverse-exponential curve, MTBF decreases with time)
2. The probability of wear-out failure-modes occuring (an exponential curve, MTBF increases over time)
3. The probability of "random" or complex failures which, as predicted by the central limit theorem, approximates to a "constant failure rate" (constant MTBF).

The first of these can be mitigated using process controls and burn-in testing. The second one defines the "product ultimate life" which can be tested for and predicted using Weibull analysis. The third one should ideally represent the in-service period where MTBF is both known and constant. As a result the manufacturer can make a reasonable stab at predicting the likely risk-cost of any given warrant period. So they choose a cost they can tolerate and then calculate the warranty period that should deliver this. Now remembering that the whole concept of MTBF is based on the exponential distribution (so even though it is the MEAN time between failures at that actual time you would expect 63% of the population to have failed*) you clearly don't want to be anywhere NEAR the MTBF time when your warranty period ends. If you were then you could expect your warranty costs to be around 63% of your costs-to-sale, and no one carries that much profit margin.

The usual number used is called the "B10 life" or "B10 component life" - that point at which 10% of the items made would be expected to have failed. Depending on whether (and how much) burn-in or other type-1 (above) mitigation is done this would typically be at anywhere from 3% to 9% of the MTBF. So if the manufacturer offers a 2 year warranty it usually means they expect most of the product sold will last AT LEAST another eight years, and probably longer, unless there is a spoecific wear-out failure mode that would truncate it. There are alos minor variations in these sums depending on whether it's a "Free Replacement Warranty" where they will repair/replace failed items free of charge, or a "Pro-Rata Warranty" where the customer would be expected to contribute to the repair or replacement cost in proportion to the amount of the expected life that had already passed (as for typical 3rd-party mechanical breakdown "warranties" - see also "Betterment Clause").


If you read the above you should see why a manufacturer may be able to give a warranty at no extrat cost, but the "store checkout" warranty will ALWAYS be more expensive. The Manufacturer can mitigate the warranty costs through process control and testing, but the retailer has no control over the probability of failure and is just taking a punt...

[I'll come clean - a few weeks ago I gave a 1 hour seminar to the Divisional Management Committee of our electronic equipment division on subject of warranty risk - how it is calculated and what is needed to manage it as a business risk, so I still have the slides if anyone wants to see them!]


* if that isn't immediately clear look up the properties of exponential curves and integrate one from 0 - 50%)
RC Flight Chatter / Re: Wot4 Foam-e Mk2 wing fixing
« Last post by itsme on September 23, 2018, 16:16:19 PM »
What has surprised me is that I had an E-wottie a few years back which did a lot of work until the elevator servo failed in flight (after about 5 minutes and yes, everything worked OK on the ground) so  I bought another one last year. With Veronica's illness and death I didn't get round to flying it until this April - and it is WAY tail heavy - I was quite proud of myself for getting the thing down in one piece (until the breeze caught it and a semi-cartwheel tore the wing loose). Haven't got round to doing anything about it yet - motivation at the moment is very low - haven't actually gone flying since that day. However, can't understand how, when the first one flew perfectly out of the box, number two - with identical radio gear and battery size, weight and location - could be so way out of trim. Checking after the event, I would have thought the CG was reasonably located  - but it didn't seem it whilst in flight. Trouble is, I never made a note of the CG position on number one, so have no idea how they compare.
Usually they are spot on..

Sent from my SM-A300FU using Tapatalk

Pages: [1] 2 3 4 5 6 ... 10
BloQcs design by Bloc
SMF 2.0.2 | SMF © 2011, Simple Machines
SMFAds for Free Forums
TinyPortal © 2005-2012
Page created in 0.319 seconds with 19 queries.