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Member postings for Brian Parker

Here is a list of all the postings Brian Parker has made in our forums. Click on a thread name to jump to the thread.

Thread: Loverrly legs
07/07/2011 19:06:41
It's my accent

Edited By Brian Parker on 07/07/2011 19:08:19

07/07/2011 19:02:57
It’s only serrated to allow for loose manufacturing tolerances.
You need to make a new bush, (does it need to be as long as 17mm? Probably not).
Take up Alan’s offer or start making swaff.

Edited By Brian Parker on 07/07/2011 19:05:21

07/07/2011 14:36:52

Expansion rate of Aluminium and brass is very similar ( Al. slightly higher). As expansion is linear the brass will loosen.

07/07/2011 14:18:44
I’ve recently successfully fabricated crankshafts for model steam and IC engines trying both Loctite 262 and Truloc 231 (using a light press fit and then pinning).

If you need to reduce the length by 30mm and the brass bush is 30mm then it’s probably easier to make up and fit new brass bushes. Drill and tap after fitting.
If you cut the spring then it will be less ‘springy’ but the working load will not be altered. A spring is a length of bar in torsion (although it behaves slightly differently when a helix), a shorter bar twists less than a longer bar for the same load (ie. more turns, more spring).
You need a springs with the same spring rating (force/mm deflection) as the original but at the new free length to maintain the correct working length.
Or you could pop the springs in the oven with the Sunday roast for 15minutes to alter temper. Be careful whose temper you alter.
Thread: Don't just stand there, get one up!
23/06/2011 16:14:29
I’ve followed your build from the start and become more impressed with every instalment.
Thanks for sharing your progress with us, keep it coming.
Thread: A Lithoplate belly skid
21/06/2011 16:08:23

The Evo Weasel’s plastic skid is probably ornamental rather than practical, especially when flown from a rock strewn hillside.

Being fed up with replacing/repairing it I thought a belly skid fashioned from Lithoplate seemed worth testing out.


The prototype.

After forming it was give a final anneal and then planished to give it a ‘springing’ hardness.


After several landings and the odd arrival.

I’d run out of my usual modelling tape and having some white Spinnaker repair tape I used it to attach the skid. It’s non-stretch (hence the untidy attachment), tear resistant ripstop nylon. (This would be ideal for hinge tape, why haven’t I used it before?).

I just let the longer antenna of the AR500 receiver hang clear in the breeze and have encountered no problems to the limits of my eyesight.

The CoG remained unaltered.
Thread: Spark plugs
20/06/2011 06:55:14
Just Engines stock them.
Thread: A contra rotating brushless motor?
08/06/2011 11:16:03
Somebody got there first.
07/06/2011 10:05:59
Just checked a couple of sealed bearings with a meter, more an insulator than a conductor.
You could always graft insulated slip rings to the bearing casings and then add a third axial slip ring (insulated) to the ‘stator’ shaft.
06/06/2011 10:31:14
Interesting thought Simon, after all the brushless stator isn’t aware that it isn’t rotating and it shouldn’t bother the ESC either.
It won’t be a brushless motor after modification though.
Thread: RCGF 26cc petrol - help needed
24/05/2011 14:58:21
If the fuel lines/connections/tank etc. are all OK, then the pump isn’t sucking.
These carbs are not difficult to disassemble as long as a clean, methodical approach is taken.
I suspect (as I stated earlier) that the valves aren’t sealing or the diaphragm is faulty.
Or perhaps its a faulty pulse pipe connection.
Or even crankcase air leakage (although as the engine was running, the least likely option).
Also check the float needle it could be sticking.
The pump diaphragm operates via the pulse pipe and the varying crankcase pressure/depression as the engine runs/turn over, this draws fuel into the carb. This pipe is a control pipe it is not a fuel pipe.
20/05/2011 17:37:40
The small tube you describe is the pulse pipe for the diaphragm pump.
If you are sure that no air is leaking into the system, then the next step is to strip and examine the fuel pump, checking the fuel pump diaphragm/ flap valves for operation. You may have a faulty diaphragm or dirt preventing the valves from closing.
Also check the float needle/ lever/ float diaphragm for correct operation/integrity.
Check condition of gaskets/diaphragms and seals and vents air and reassemble, set to initial settings and test run.
Good luck.
19/05/2011 19:33:20
On the initial settings the engine should be able to operate at full throttle.
If not..Is the choke open?
Is it too lean? (Open the high end screw a fraction).
Have you tried a larger prop to give a greater load?( Less RPM but perhaps full throttle).
On the timing I omitted to add that at TDC the sensor should be 28degrees advanced from the magnet.
Is the plug gapped correctly?
Is the fuel/oil mix correct (30/40:1?)
Does it ‘four stroke’ before it dies at high throttle opening, if so and you can alter the ‘die’ RPM by adjusting the high and/or low screws, the fault is with the Carb.
If it cuts completely at a certain RPM and can be picked up again by quickly reducing the throttle slightly then you have an ignition fault.
Hard to fully diagnose at a distance.
Thread: Lith plate anybody........
19/05/2011 15:10:52
I just use a standard plumbers gas torch with a Butane/Propane canister on a low heat.
Thread: RCGF 26cc petrol - help needed
19/05/2011 15:02:53
As I recall,
On the Walbro carburettors the Low running screw is usually the one nearest to the engine, the High running screw is at the intake end.
Seems (unusually) both screws are out of adjustment.
Your low running screw should initially be close to 1 ½ turns out and the high speed screw 1 ¾ out.
It pays first to check the static timing. The magnet should be at TDC when the piston is at TDC.
With the engine warm, adjust the high speed screw for maximum revs.
Then reduce revs and hold the throttle steady close to 2000rpm and then adjust low speed screw for maximum revs at that throttle setting.
Let the engine idle.
Then adjust, as necessary the slow screw to give smooth transition from idle to max revs.
Repeat if required.
Final settings should ideally within ½ turn of initial setting.
Hope this helps.
Thread: Lith plate anybody........
19/05/2011 14:07:17
19/05/2011 12:10:21
Mine arrived yesterday and gave it brief test with a steel ball and length of tube, hand pressure only.


Discolouration is due to not removing the ‘blue’ coating before annealing. (This can be removed before annealing using Meths).

It needed to be annealed four times to achieve the form.

I never bother with a soap coating before annealing, I just warm it up.


Edited By Brian Parker on 19/05/2011 12:12:11

16/05/2011 17:02:45
Well spotted!
Just bought myself a pack
Thread: High voltage low current.
30/12/2010 19:40:01
Nasa Steve
When did I say Ohms law changes with temperature?
 I was referring to the calculated result.
30/12/2010 18:20:47
The Ohms law calculation is only true for a constant temperature. Change the temperature and you need to re-calculate due to the change in resistance. The formula is simply an algebraic form of the law and assumes a constant temperature.
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