Here is a list of all the postings MAD Dave has made in our forums. Click on a thread name to jump to the thread.
|Thread: Nimrod MR2 undercarriage|
Craig, presumably your Nimrod has flown by now, I would be grateful if you could give a report on how it all went. I have wanted to build and fly a model of it for many years and only recently discovered the plans,;of which I am now a proud owne! Like yourself, I had a professional association with the airframe. Any tips etc would be most appreciated.
|Thread: Fleet Control Systems|
I used Fleet equipment in my youth, 27MHz & 35MHz, before constructing my own set of the featured RCM&E 35MHz equipment - who remembers that? Never suffered any problems with any of it with one exception. The NiCad's provided with the 35MHz Fleet gear would not hold a proper charge; one duff cell maybe. A diversion off the M3 one day to Fleet sorted the problem. I called in, told Derek about it, there was no argument and he said "Fine". He then invited me to go upstairs in his shop, on my own, and help myself to a set of new ones; third cabinet on the left, second shelf etc. This I did and what an (unattended) Aladdin's Cave confronted me! We had not met before and he did not know me, I was amazed at the level of trust shown, a rare thing these days perhaps. The visit is something that sticks in my memory. That M3 diversion later became more of a routine but for all the good reasons. Different times perhaps.
|Thread: See if you can help me with this|
My take on David’s question 1 (For what it’s worth!).
Continuous power is measured in Watts; Volts x Amps in the basic sense. For batteries, we of course have a time factor, hours, because they are limited in the total amount of power they can supply.
For example, a 4000mAh 3s battery (~11.1V) stores a nominal 44400mWh power charge; 44.4Wh. Similarly, a 2000 mAh, 6S battery (~22.2V) at will also hold 44400mWh.
All electric motors have a maximum continuous power rating in Watts before the inevitable occurs; should they be asked to deliver more!
If a 630kV motor uses the 3S battery above, the maximum rpm would be expected to be around 7,000.
Using an in-line Watt meter, one chooses a propeller that will cause the motor, at max throttle, to draw the maximum power as specified in the suppliers guide – or maybe a little less to be on the safe side!
If a 6S LiPo was then substituted, the motor would then try to turn the same prop at around 14,000rpm and probably emit a little smoke before it got there – which it didn’t of course!
With the same Watt meter arrangement, one would chose a smaller prop that would present the motor with a reduced load/rpm yet retain the same max power consumption at max throttle, 14,000rpm in this example.
More S’s, smaller props! Q.E.D!
One point alluded to earlier is to bear in mind is that for the same power delivered through the cables, a higher voltage reduces the current that flows.
The advantages of reduced current is that there will be reduced volts losses at connectors (due to their contact resistance – V=IR etc. more volts for the motor, but not a lot necessarily) and the ESC will not need to be so “Ampy”! Also the desired maximum discharge current rating of the battery will be reduced, saving funds for the next project and perhaps extending the life of your battery too!
In the examples above, minimum Amp spec’s for a 550W motor would be approximately 25Amp for a 6S battery and 50Amp for a 3S battery; on the safe side, perhaps 30amp and 60Amp respectively.
So, in order to choose how many S’s provide optimum performance, do we now start a debate/thread about propeller efficiency with respect to rpm, diameter, pitch, etc, etc…….?!
|Thread: futaba T10J|
Mode 3 is a mirror image of Mode 2 re stick functionality.
Thanks CARPERFECT, will consider your offer. Re the change to Mode 3, presumably the throttle ratchet and sprung centering changeover requires a little surgery? How easy/simple is that would you know?
I have flown since returning post children using Futaba T6J. Have been thinking for awhile about catching up with developments and investing in a new Tx. The T10J looks attractive but I fly with Mode 3; left handed. The change to '3 on the T6J was simple enough. Does anyone know whether it is similarly simple on the T10J please?
|Thread: Glue advice please.|
Thanks guys, I'll mull over it.
|Thread: Scottish Aviation Twin Pioneer CC Mk 2|
I remember seeing one of those almost flying backward in a strong wind!
|Thread: Glue advice please.|
I have just removed a little grass from mother earth with my Flyingwings Raven. Fortunately, the only damage was a detached aileron. On this model, the ailerons are attached by a thin line of flexible glue. Does anyone know what glue this is please? The method of attachment may sound a little "basic" but it has served quite satisfactorily for many years; a great fun-plane.
|Thread: Additional battery?|
I'm with Allan Bennett. The DA solution may be okay under normal circumstances but should one pack develop a problem, the associated wiring/switches/Rx could suffer badly should one low internal impedance battery pass a high current to the faulty one; don't like it and would never use it. Probably okay most of the time though but I would regard it as a big-time problem waiting to happen. (MAD Dave CEng etc.)
|Thread: From where might I acquire a Pulse XT60?|
Oh dear, suffering from dyslexia now....
Slightly gobsmacked, the Amazon seller is listed as
Hi guys, thank you for all your support but I did not make it clear - I DID order one of the two that Amazon were showing as in stock and that is why, as John reports, they only have one remaining. So, perhaps it seems I am not so mad after all!! Cheers Phil! I am told to expect delivery by the 14th April.
Thank you Martin, they only have one left in stock now! I had checked on Amazon earlier but for some reason it did not come up. Agreed the postage is a bit steep but.......
I unfortunately wrote off my electric Hangar 9 Pulse XT60 today; my fault. During its short life, I really enjoyed flying it.
It went vertically into soft soggy clay with the spinner tip stopping some 30cm depth. The motor, ESC, battery, Rx and servos appear to have survived intact, thanks to the nature of the soil perhaps but the airframe, well, I need a replacement, preferably an ‘XT60.
I was not previously aware, but on searching the net this evening, it seems the model has been discontinued and is therefore unavailable from the normal sources.
If anyone knows of any “old stock”, I would be very pleased to hear from them. Equally, a “pre-owned” model would be appreciated. I can collect; my post code area is BH20.
An alternative of course would be to go to a different design. Does anyone have any recommendations for a model of similar size, performance and behavioural characteristics please? The motor I have is an E-flite Power 60 which I operate on 6S; the combination pulls quite well!
Thanks in advance for any assistance given.
|Thread: Odd servo fault|
I have experienced something slightly similar in the past, what make Tx & Rx are you using Chris?
|Thread: Scam or what ?|
If I have the time, I take the line that there is definitely nothing wrong with my PC, therefore theirs must be experiencing technical problems. Some just hang up but the more entertaining calls are those where we debate the issue trying to "out-tech" each other - before they hang up. Can be good fun but I know I should be out working in the hangar........
|Thread: Canberra by Andy Blackburn PSS|
I believe most "bubble canopy" Canberras had two seats at the front. The pilot's Martin Baker armchair plus, to his right, a foldable "Rumbold" (Google it) non-ejection seat for use by brave men. Two occupants would therefore not necessarily be incorrect. Twin MB's on the T4 accepted of course!
|Thread: Screw thread identification - Pulse 60.|
Thanks everyone, I now have my way-ahead sorted! Good these forum things..........
I am putting together my shiny new Pulse 60 and, as advised, am replacing the undercarriage assembly with something a little more "stout". This renders the supplied two fuselage securing screws too short.
In order to acquire replacements of an appropriate length, I first of course need to identify the thread but have been unable to do so.
I do not believe it to be anything metric but the favoured guess to date is 5/32 BSW. Does anyone know for sure what it is before I am forced to purchase a box of 100?!
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